Avaliação da performance no treino em jogos desportivos coletivos
Transcription
Avaliação da performance no treino em jogos desportivos coletivos
Eduardo André de Azevedo Abade Avaliação da performance no treino em jogos desportivos coletivos Tese de Doutoramento em Ciências do Desporto Orientador: Professor Doutor António Jaime da Eira Sampaio Universidade de Trás-os-Montes e Alto Douro Vila Real, 2014 Eduardo André de Azevedo Abade Avaliação da performance no treino em jogos desportivos coletivos Este trabalho foi expressamente elaborado com vista à obtenção do grau de Doutor em Ciências do Desporto de acordo com o Decreto-lei 115/2013 de 7 de Agosto. O trabalho apresentado nesta dissertação foi suportado pela Fundação para a Ciência e Tecnologia (Portugal) bolsa SFRH / BD / 74544 / 2010 Universidade de Trás-os-Montes e Alto Douro Vila Real, 2014 ii “Se acha que a educação é cara, experimente a ignorância” Derek Bok iii DEDICATÓRIA Aos meus pais, Eduardo José Abade e Maria Antonieta Abade e irmão Tiago Abade. Não há nada melhor que me pudessem ter dado que uma boa educação! iv AGRADECIMENTOS / ACKNOWLEDGEMENTS “A vida deve ser uma constante educação”! Mais uma etapa cumprida com o apoio indispensável de professores, família e amigos. Para eles o meu sentido agradecimento. Ao professor Jaime Sampaio pela orientação imaculada. Pela disponibilidade diária (literalmente), pelo apoio, paciência, espírito crítico e rigor que tão bem o caracterizam. Não há preço que pague os últimos 4 anos de educação profissional e pessoal que me prestou. Pelos “ok”, “boa”, “excelente”, “gosto”, “não gosto”, “corrige”…o meu muito obrigado. A viagem ainda agora começou, espero eu! Ao Bruno Gonçalves pela preciosa e insubstituível participação neste trabalho. Pelas horas e horas de conversa, debate, partilha de conhecimento e companheirismo. É difícil explicar o caminho desde o primeiro “olá, então o que é que fazes aqui no laboratório?” até hoje. De colega a amigo! Ao Bruno Figueira e ao Diogo Coutinho pela colaboração em todo o processo, desde o primeiro dia! O vosso apoio foi fundamental em todos os momentos, bons e menos bons. Obrigado pela troca de ideias, experiências e conhecimentos. Obrigado pelas insubstituíveis gargalhadas e brindes Amigos! À Alexandra e aos professores Nuno Leite, Catarina Abrantes e José Vilaça pelo contributo científico prestado na elaboração deste trabalho. Ao professor Carlo Castagna pela fantástica experiência que me proporcionou em Itália, pela atenção prestada e competência profissional. Agradeço igualmente a sua colaboração científica na realização deste trabalho. A todos os colegas (Sara, Nuno, Laura, Rui, Manuel) e professores (Luís Vaz, Vítor Maçãs, Isabel Gomes, Paulo Vicente) do CreativeLab pela ajuda direta ou indireta que prestaram na elaboração deste trabalho. Ao Tiago Oliveira um especial obrigado pelo seu contributo...a pessoa mais apaixonada por Andebol que alguma vez conheci. Obrigado pelas ideias andebolísticas que partilhaste comigo. Ainda nos vamos cruzar no retângulo de jogo, como adversários ou colegas de equipa! Aos professores Paulo Sá e Mário Santos pela total disponibilidade, paciência, colaboração e apoio prestados durante o processo de recolha de dados. Mas acima de tudo pela vossa amizade. A vós devo muito do que tenho conseguido alcançar. Temos com certeza um portfólio de momentos desportivos para mais tarde recordar, mas as verdadeiras memórias terão sempre os pés debaixo da mesa. Aos jogadores da ADA/Maia ISMAI pelo irrepreensível contributo dado na realização deste trabalho. Foram 8 anos de trabalho fantásticos, da base ao topo. É um orgulho olhar para trás e ver o percurso trilhado até ao presente. Ao professor Alberto Carvalho por me ter incutido a verdadeira paixão pelo treino desportivo. Não me esquecerei nunca do passo acelerado e abraço que me deu no v momento imediatamente após a defesa da tese de licenciatura. O “obrigado” nunca será suficiente para agradecer o que tem feito por mim e pelas competências que me tem transmitido. Obrigado por acreditar. Ao professor João Paulo Barbosa por me ter ensinado o significado das palavras “competência” e “empreendedorismo”. Em algum lado teria que estar escrito que seria meu/nosso orientador do estágio pedagógico. Foi um dos anos mais marcantes da minha formação académica. Obrigado por ter incentivado a leitura e procura do conhecimento. Obrigado pelos fantásticos anos que passámos juntos no Andebol. Aos treinadores José Carlos Ribas, Raquel Silva, Paulo Ribas e Susana Leal pela troca de experiências proporcionada ao longo de anos. A vossa dedicação ao Andebol é ímpar. Às jogadoras do Maiastars, da formação às seniores, por estarem sempre disponíveis para colaborar. Mas acima de tudo pelo que aprendi com vocês. Proporcionaram-me aprendizagens e momentos inigualáveis. Ao professor Nuno Montenegro pelos assertivos e sábios conselhos que me deu durante o estágio pedagógico. Ainda hoje respeito alguns dos seus mandamentos. Ao professor Rolando Freitas por ter acreditado no meu valor. A todos os professores com quem me cruzei. Tive uma tremenda sorte em vos ter como tutores. Aos meus alunos, porque a melhor maneira de aprender é ensinar. A toda a minha família, Tios, Primos e Avós por tudo o que significam. Á minha Tia Isabel pelo carinho sem limites que tem pelo seu sobrinho. Obrigado por tudo madrinha! À Filipa, a minha melhor amiga, confidente e companheira. Obrigado pelos constantes sacrifícios, por estares sempre presente, pelas discussões saudáveis e construtivas…e pelas fantásticas viagens. Obrigado pelo teu carinho insubstituível! Ao Carlos, Fernando, Filipe e Tiago (ordem alfabética) pela vossa amizade! Porque Amigos há poucos…vocês são “aqueles” e sabem-no porquê. A todos os meus colegas de licenciatura. Pelo que aprendi com vocês e pelos momentos inesquecíveis que proporcionaram. A todos aqueles que por lapso não estão aqui mencionados mas que contribuíram de uma ou outra forma para a conclusão deste trabalho. vi RESUMO O planeamento a curto prazo em jogos desportivos coletivos representa um desafio para os treinadores, uma vez que o microciclo semanal inclui sessões de treino com objetivos múltiplos. A necessidade de manter ou melhorar a capacidade física, o desenvolvimento das habilidades técnicas e o treino tático, convergem numa complexidade de conteúdos que requer conhecimentos profundos acerca das suas interações, no sentido de otimizar a periodização e o planeamento do treino. Neste sentido, conhecer os perfis de carga externa e interna dos jogadores torna-se imprescindível para um planeamento dirigido à melhoria da performance desportiva. Uma vez que o treino técnico-tático é incapaz de induzir adaptações neuromusculares significativas, a primeira parte deste estudo procurou descrever os efeitos agudos que a adição de sessões específicas de treino de força teve na resposta física, fisiológica e performance técnico-tática em sessões de treino de Andebol. O treino de força mostrouse influenciador da intensidade do esforço durante a prática dos jogos reduzidos. Os jogadores passaram mais tempo em zonas elevadas de frequência cardíaca quando existiu treino de força antecedente. Em sessões de treino com jogos reduzidos 6x6, o treino de força mostrou-se útil no aumento da intensidade do esforço, não deteriorando a capacidade de salto. Mesmo antecedendo jogos reduzidos 3x3, o treino de força promoveu aumentos do tempo passado em zonas elevadas de frequência cardíaca, assumindo-se como uma ferramenta apropriada para o desenvolvimento da performance aeróbia em contexto de jogo. No entanto, os treinadores deverão considerar a possibilidade da ocorrência de mais falhas técnicas e diminuição da eficácia no remate quando o treino de força antecede sessões de jogos reduzidos com um menor número de participantes. A segunda parte desta tese focou-se na avaliação da carga externa durante unidades de treino de futebol, através da descrição de perfis de performance e métodos de classificação dos jogadores. Aparentemente, a elevada variabilidade de estímulos é uma característica transversal às sessões de treino de equipas jovens de elite (sub-15/17/19). O foco no desenvolvimento de princípios táticos básicos e habilidades técnicas em idades mais jovens (sub-15) parece diminuir o estímulo fisiológico. Por outro lado, à medida que a idade biológica avança, os treinadores parecem privilegiar mais situações de jogo, o que resulta num aumento significativo da intensidade do treino. Esta vii tendência foi mais evidente nas unidades de treino de escalões sub-17, constituídas por jogos reduzidos com poucos constrangimentos que induziram valores mais elevados de distâncias totais e distâncias percorridas em sprint. Em idades mais avançadas (sub-19), as interrupções e feedbacks recorrentes da crescente preocupação com os modelos táticos das equipas parece comprometer o padrão fisiológico competitivo. Esta descrição dos perfis físicos e fisiológicos foi ainda utilizada para classificar os jogadores em grupos distintos de performance, em detrimento de critérios comuns como a idade e posto específico. O estabelecimento de grupos homogéneos reduziu a variabilidade na resposta ao estímulo, o que permite aos treinadores um controlo mais eficiente das respostas às cargas de treino. Palavras-chave: Planeamento a curto prazo; carga interna; carga externa; treino de força; jogos reduzidos; perfis de performance; andebol; futebol. viii ABSTRACT Short-term planning in team sports is challenging for coaches, since the weekly training cycles include sessions with multiple goals. The need to maintain or improve the physical capacity, the development of technical skills and tactical training, represent a complexity of contents that require a significant knowledge of its interactions in order to optimize the training processes. In this sense, studying the players’ internal and external loads profiles is a key issue to establish training programs aimed for the improvement of sports performance. Technical and tactical training do not induce significant neuromuscular adaptations. For that reason, the first part of this study described the acute effects of specific strength training sessions in the physical, physiological, technical and tactical response during handball small sided games. It was showed that strength training influenced the intensity of the effort during small sided games. The players spent more time in higher heart rate zones when there was precedent strength training. In training sessions that included 6x6 small sided games, strength training was able to increase training intensity without impairing the vertical jump capacity. Even when strength training preceded 3x3 small sided games, players experienced more time in higher heart rate zones. Thus, strength training may be used as an appropriate tool to develop the aerobic performance in game context. However, coaches should consider the occurrence of a higher number of technical errors and the deterioration of the shots efficiency when strength training precedes small sided games with a lower number of players. The second part of this thesis focused on the evaluation of the external load during football training units, using the description of performance profiles and methods of classifying the players. Apparently, the high variability of stimuli is a key characteristic of elite young football training sessions (sub-15/17/19). The focus on the development of basic tactical principles and technical skills in younger ages (sub-15) seems to decrease the physiological stimulus. On the other hand, as the biological age increases coaches seem to privilege more game situations, which results in higher training intensities. This trend was clearer in sub-17 training units that included small sided games with fewer constraints, inducing higher values of total distances and distances covered in sprint. In older ages (sub-19), the focus on team tactical principles appears to require additional coaching intervention, promoting more interruptions and compromising the replication of the competitive physiological pattern. This description ix of the physical and physiological profiles was also used to classify the players in different groups of performance, contrasting the traditional criteria of classification based on age and specific playing position. The establishment of homogenous groups reduced the variability of the response to stimuli, allowing coaches to have a more accurate and efficient control on the players’ responses to training loads. Key words: Short-term planning; internal load; external load; strength training; small sided games; performance profiles; handball; football. x LISTA DE PUBLICAÇÕES E COMUNICAÇÕES Durante a elaboração desta tese, alguns trabalhos foram publicados, aceites ou submetidos para publicação em revistas indexadas (ISI) com sistema de arbitragem. Algumas partes integrantes ou derivadas da tese foram apresentadas em congressos, publicadas em livros de resumos e em edições especiais de jornais científicos. Foi também realizada uma visita de investigação. Artigos em revistas indexadas no ISI com sistema de arbitragem, como primeiro autor Abade E, Gonçalves B, Leite N and Sampaio J (2013). Time-motion and physiological profile of football training sessions performed by under 15, under 17 and under 19 elite Portuguese players. International Journal of Sports Physiology and Performance. (Acceptance Date: June 27, 2013, Impact factor = 2.3) Abade E, Abrantes C, Ibañez J and Sampaio J (Under Review). Acute effects of strength training in the physiological and perceptual response in handball small-sided games. Abade E, Gonçalves B, Vilaca J and Sampaio J (Under Review). Acute effects of different strength training programs on the vertical jump and technical actions in handball small-sided games during preseason. Abade E, Gonçalves B, Silva A, Leite N, Castagna C and Sampaio J (Submitted). Helping coaches to classify young footballers according to their training performances. Artigos em revistas indexada no ISI com sistema de arbitragem, como co-autor Oliveira T, Abade E, Gonçalves B and Sampaio J (Submitted). Physical and physiological profiles of elite handball players during training sessions and friendly matches according to playing positions. xi Resumos publicados em livros de atas de encontros técnico-científicos Abade E, Oliveira T, Gonçalves B & Sampaio J (2013). Strength and conditioning for team sports: an update. Atas do 3º Simpósio Internacional de Força e Condição Física. ISBN: 978-989-704-142-6 Comunicações orais em congressos técnico-científicos Abade E (2013). Strength and conditioning for team sports: an update. 3º Simpósio Internacional de Força e Condição Física. Universidade de Trás-os-Montes e Alto Douro, Vila Real. Abade E (2013). Metodologias de treino – novas perspetivas. 4º Congresso Internacional Handball Project, “Pensar o Andebol em 2030”. Maia, Portugal. Abade E (2013). Importância e organização do treino de força para performances desportivas de excelência. Seminário de investigação nos jogos desportivos coletivos. Universidade de Trás-os-Montes e Alto Douro, Vila Real. Abade E (2012). Efeitos agudos do treino de força em jogos reduzidos. Seminário Brainstorming – fundamentos e aplicações à investigação nos jogos desportivos coletivos. Universidade de Trás-os-Montes e Alto Douro, Vila Real. Abade E (2012). Efeitos do treino de força e jogos reduzidos na carga de treino em jogadores de Andebol. VI Seminário técnico-científico da Federação Portuguesa de Andebol. Maia, Portugal. Abade E (2012). Treino de potência para jogadores de Andebol. VI Seminário técnicocientífico da Federação Portuguesa de Andebol. Maia, Portugal. Abade E (2012). A importância do treino de força na prevenção de lesões. VI Seminário técnico-científico da Federação Portuguesa de Andebol. Maia, Portugal. Visitas de investigação FIGC, Settore Tecnico Coverciano – Laboratorio di metodologia dell’allenamento e biomeccanica applicata al calcio. Federação Italiana de Futebol (FIGC). Coverciano, Florença, Itália (2013). xii OUTRAS PUBLICAÇÕES Outros trabalhos foram desenvolvidos paralelamente à elaboração desta tese, como primeiro ou co-autor. Artigos em revistas indexada no ISI com sistema de arbitragem, como co-autor Carvalho A, Caserotti P, Carvalho C, Abade E and Sampaio J (2013). Reliability of concentric, eccentric and isometric knee extension and flexion with the REV9000 isokinetic dynamometer. Journal of Human Kinetics. Vaz L, Abade E, Fernandes H and Reis V (2013). Cross-training in rugby: a review of research and practical suggestions. International Journal of Performance Analysis in Sport. Azevedo R, Mourão P, Abade E and Carvalho A (Under Review). Is it important to know the load mass in lifting tasks to prevent falls? Carvalho A, Caserotti P, Carvalho C, Abade E and Sampaio J (Under Review). Effects of a short time concentric versus eccentric training in electromyography activity and peak torque of quadriceps. Carvalho A, Mourao P and Abade E (Under Review). Effects of strength training combined with specific plyometrics on body composition, vertical jump height and lower limb strength development in elite male handball players: a case study. Carvalho A, Carvalho C, Caserotti P, Abade E and Sampaio J (submitted). Effects of a short-time concentric versus eccentric training and detraining in the peak torque of quadriceps and hamstrings. Carvalho A, Abade E, Carvalho C and Sampaio J (Submitted). Reliability of Electromyography and peak torque during maximum voluntary concentric, isometric and eccentric contractions of quadriceps muscles in healthy subjects. Resumos publicados em livros de atas de encontros técnico-científicos Carvalho A, Mourão P, Resende R, Abade E. and Carvalho C (2013). Comparison of anthropometric profiles between different senior male Volleyball competition levels: xiii national team, first and second Portuguese divisions. 18th annual Congress of the European College of Sport Science. Barcelona, Spain. ISBN: 978-84-695-7786-8. Carvalho C, Mourão P, Sá P, Abade E and Carvalho A (2013). Comparison of anthropometric profiles between different senior male Basketball competition levels: first, second and third Portuguese divisions. 18th annual Congress of the European College of Sport Science. Barcelona, Spain. ISBN: 978-84-695-7786-8 Mourão P, Abade E, Martins D, Gonçalves F, Carvalho A and Viana J (2012). Effectivness of a neuromuscular and proprioceptive combination training program in preventing injuries in youth soccer players. In International Seminar on Physical Activity and Related Injuries. University of Trás-os-Montes e Alto Douro, Vila Real. Acta Med Port, 25, 9. ISSN:0870-399X, e-ISSN:1646-0758 Carvalho A, Abade E, Carvalho C and Mourão P (2012). Is isokinetic conventional ratio “Hcc:Qcc” a good indicator of injury?. In International Seminar on Physical Activity and Related Injuries. University of Trás-os-Montes e Alto Douro, Vila Real. Acta Med Port, 25, 8. ISSN:0870-399X, e-ISSN:1646-0758 Comunicações poster em congressos técnico-científicos Carvalho A, Mourão P, Resende R, Abade E and Carvalho C (2013). Comparison of anthropometric profiles between different senior male Volleyball competition levels: national team, first and second portuguese divisions. 18th annual Congress of the European College of Sport Science. Barcelona, Spain. Figueira B, Gonçalves B, Coutinho D, Abade E, Freitas R, Leite N, and Sampaio J (2013). O perfil físico e fisiológico da competição pode classificar jovens futebolistas! 8º Seminário de Desenvolvimento Motor da Criança. Universidade de Trás-os-Montes e Alto Douro, Vila Real. Sá P, Carvalho A and Abade E (2013). O jogador especialista na defesa de Andebol. 2º Congresso internacional de treino desportivo. Instituto superior da Maia. Maia, Portugal. Carvalho C, Mourão P, Sá P, Abade E and Carvalho A (2013). Comparison of Anthropometric Profiles between different senior male Basketball competition levels: xiv first, second and third Portuguese divisions. 18th annual Congress of the European College of Sport Science. Barcelona, Spain. Sá P, Carvalho A and Abade E (2013). Análise e preponderância do contra-ataque no jogo de Andebol. 2º Congresso internacional de treino desportivo. Instituto superior da Maia. Maia, Portugal. Coutinho D, Gonçalves B, Figueira B, Abade E, Oliveira T, Maçãs V, and Sampaio J (2013). Variação do perfil físico e fisiológico de jovens futebolistas ao longo de uma competição concentrada. 8º Seminário de Desenvolvimento Motor da Criança. Universidade de Trás-os-Montes e Alto Douro, Vila Real. Abade E, Silva B, Santos F and Sá P (2012). Strength training methodologies applied to elite handball teams. 9º Congresso técnico-científico de Andebol. Universidade Lusófona, Lisboa, Portugal. Carvalho A, Mourão P, Abade E and Carvalho C (2012). Power and explosive strength comparison between men volleyball national team players. 8th International Conference on Strength Training. Norwegian School of Sport Sciences. Oslo, Norway. Mourão P, Abade E, Martins D, Gonçalves F, Carvalho A and Viana J (2012). Effectivness of a neuromuscular and proprioceptive combination training program in preventing injuries in youth soccer players. Physical activity and related injuries international seminar. University of Trás-os-Montes e Alto Douro, Vila Real, Portugal. Carvalho A, Abade E, Carvalho C and Mourão P (2012). Is isokinetic conventional ratio “Hcc:Qcc” a good indicator of injury?. Physical activity and related injuries international seminar. University of Trás-os-Montes e Alto Douro, Vila Real, Portugal. Carvalho A, Abade E, Mourão P and Carvalho C (2012). Efeitos de um programa de treino de força combinado com pliometria específica na composição corporal, impulsão vertical e força dos membros inferiores em jogadores seniores de andebol. Congresso internacional de treino desportivo. Instituto Superior da Maia, Portugal. Carvalho A, Mourão P and Abade E (2012). Comparação da força explosiva e reativa entre atletas pertencentes à seleção nacional masculina de voleibol. Congresso internacional de treino desportivo. Instituto Superior da Maia, Portugal. Silva B, Abade E, Santos F and Sá P (2012). Scouting no Andebol. Congresso internacional de treino desportivo. Instituto Superior da Maia, Portugal. xv Santos F, Abade E, Silva B and Sá P (2012). O modelo de jogo numa equipa de Andebol. Instituto Superior da Maia, Portugal. Comunicações orais em congressos técnico-científicos Oliveira T, Abade E, Gonçalves B and Sampaio J (2013). Physical and physiological profiles of youth elite handball players during training sessions and friendly matches according to playing positions. 10º congresso técnico-científico da Federação Portuguesa de Andebol, Universidade Lusófona, Lisboa. xvi ÍNDICE DEDICATÓRIA IV AGRADECIMENTOS / ACKNOWLEDGEMENTS RESUMO V VII ABSTRACT IX LISTA DE PUBLICAÇÕES E COMUNICAÇÕES XI LISTA DE TABELAS XX LISTA DE FIGURAS XXI CAPÍTULO 1 23 1.1. 24 INTRODUÇÃO 1.1.1. A COMPLEXIDADE NOS JOGOS DESPORTIVOS COLETIVOS 24 1.1.2. MODIFICAR O CONTEXTO PARA OTIMIZAR A APRENDIZAGEM 25 1.1.3. COMO CONTEMPLAR A COMPLEXIDADE NO TREINO DOS JOGOS DESPORTIVOS COLETIVOS? 28 1.1.4. 30 DIMENSÕES DOS JOGOS REDUZIDOS 1.1.4.1. Dimensão muscular 32 1.1.4.2. Dimensão energética 36 1.1.4.3. Dimensão técnico-tática 38 1.1.5. PLANEAMENTO A CURTO PRAZO NOS JOGOS DESPORTIVOS COLETIVOS 43 1.1.5.1. Efeitos agudos do treino de força nos perfis de performance de andebolistas 43 1.1.5.2. Variabilidade nos perfis de resposta de jovens futebolistas às cargas de treino 49 1.2. OBJETIVOS E HIPÓTESES 52 1.3. REFERÊNCIAS 53 CAPÍTULO 2 2.1 71 ACUTE EFFECTS OF STRENGTH TRAINING IN THE PHYSIOLOGICAL AND PERCEPTUAL RESPONSE IN HANDBALL SMALL-SIDED GAMES 72 2.1.1 ABSTRACT 72 2.1.2 INTRODUCTION 73 xvii 2.1.3 METHODS 75 2.1.3.1 Subjects 75 2.1.3.2 Design 75 2.1.3.3 Methodology 76 2.1.3.4 Statistical Analysis 77 2.1.4 RESULTS 77 2.1.5 DISCUSSION 79 2.1.6 CONCLUSION 82 2.1.7 REFERENCES 83 CAPÍTULO 3 3.1. 88 ACUTE EFFECTS OF STRENGTH TRAINING PROGRAMS ON THE VERTICAL JUMP AND TECHNICAL ACTIONS IN HANDBALL DURING PRESEASON 89 3.1.1. ABSTRACT 89 3.1.2. INTRODUCTION 90 3.1.3. METHOD 92 3.1.3.1. Participants 92 3.1.3.2. Procedures 92 3.1.3.3. Measures 94 3.1.3.4. Analysis 94 3.1.4. RESULTS 95 3.1.5. DISCUSSION 99 3.1.6. REFERENCES 104 CAPÍTULO 4 4.1. 107 TIME-MOTION AND PHYSIOLOGICAL PROFILE OF FOOTBALL TRAINING SESSIONS PERFORMED BY UNDER 15, UNDER 17 AND UNDER 19 ELITE PORTUGUESE PLAYERS 108 4.1.1. ABSTRACT 108 4.1.2. INTRODUCTION 109 4.1.3. METHODS 110 4.1.3.1. Subjects 110 4.1.3.2. Design 111 4.1.3.3. Methodology 111 xviii 4.1.3.4. Statistical Analysis 112 4.1.4. RESULTS 113 4.1.5. DISCUSSION 115 4.1.6. PRACTICAL APPLICATIONS 118 4.1.7. CONCLUSION 118 4.1.8. REFERENCES 120 CAPÍTULO 5 5.1. 123 HELPING COACHES TO CLASSIFY YOUNG FOOTBALLERS ACCORDING TO THEIR TRAINING PERFORMANCES 124 5.1.1. ABSTRACT 124 5.1.2. INTRODUCTION 125 5.1.3. METHOD 127 5.1.3.1. Participants 127 5.1.3.2. Procedures 128 5.1.3.3. ANALYSIS 129 5.1.4. RESULTS 130 5.1.5. DISCUSSION 133 5.1.6. REFERENCES 136 CAPÍTULO 6 140 6.1. 141 CONCLUSÕES E APLICAÇÕES PRÁTICAS xix LISTA DE TABELAS Table 2.1. Comparing the time spent in HR zones and RPE values according to the number of players and type of ST. .................................................................. 78 Table 3.1. Chronological schedule that preceded the protocol application .......... 93 Table 3.2. Analysis of Variance to Assess Differences in Vertical Jump Performance by Number of Players in Small-sided Games, Type of Strength Training, and Time of Testing. ............................................................................. 97 Table 3.3. Analysis of Variance to Assess Statistical Differences in % of Technical Actions by Number of Players in Small-sided Games, Type of Strength Training and Half (only statistical significant differences are presented). ........... 99 Table 4.1. Description of players’ sub-samples. ................................................ 110 Table 4.2. Analysis of distance covered, sprint characterization and body impacts across age groups. ............................................................................................... 113 Table 4.3. Mean intersection Coefficient of variation (%) according to the age groups. ................................................................................................................. 115 Table 5.1. Characterization of the cluster groups. .............................................. 130 xx LISTA DE FIGURAS Figura 1.1. Modelo de interação de constrangimentos (Newell, 1986)......................... 26 Figura 1.2. Aspetos do treino cognitivo a considerar para a construção de tarefas de treino (Fajardo, 1999). .................................................................................................... 28 Figura 1.3. Exemplo de um exercício que contempla a colaboração e oposição característica dos desportos de equipa. Em função da atuação do defensor, o atacante deve escolher entre o lançamento ou progressão com bola (Fajardo, 1999). ................. 29 Figura 1.4. Mudanças na resposta da capacidade força em 3 tipos de treino. Os registos dos grupos do treino de força e treino de força + resistência foram semanais. O grupo do treino de resistência foi avaliado no início e final do protocolo (Hickson, 1980). ......... 33 Figura 1.5. Valores médios (%FC máxima) da intensidade do exercício em diferentes situações de treino de futebol (Hill-Haas et al., 2011). .................................................. 36 Figura 1.6. Abordagem a sistemas complexos utilizada para análise da performance desportiva (Hughes & Franks, 2004). ............................................................................. 39 Figura 1.7. Duas dimensões da análise do jogo (Volossovitch, 2008). ......................... 40 Figura 1.8. Média ± SD de contactos com a bola em jogo 4x4 e 8x8 de futebol (Jones & Drust, 2007). ................................................................................................................... 42 Figura 1.9. Os principais fatores responsáveis por determinar o resultado desportivo (Verkhoshansky, 2006). .................................................................................................. 43 Figura 1.10. Modelo de treino “dois fatores”. O efeito imediato de uma sessão de TF é caracterizado pelo somatório de dois processos: ganhos na aptidão física e fadiga (Zatsiorsky & Kraemer, 2006)........................................................................................ 45 Figura 1.11. Intensidade do exercício (% FCmax) em vários formatos de jogos reduzidos de futebol (Hill-Haas, Dawson, Coutts, & Rowsell, 2009). .......................... 48 Figure 2.1. ST x HR ZONE interaction to the time spent in each one of the four HR zones (a); PLAYERS x ST x HR ZONE interaction to the time spent in each one of the four HR zones (b 3x3, b 6x6); PLAYERS x ST interaction to RPE values (c). ............ 79 xxi Figure 3.1. Results from interaction Players x Strength Training x Time for squat jump values. LOWER (lower limbs strength training); POS SSG (after small sided games); POS ST (after strength training); PRE ST (before strength training); TOTAL (upper and lower limbs strength training); UPPER (upper limbs strength training). ....................... 96 Figure 3.2. Results from interaction Players x Strength Training x Time for counter movement jump values. LOWER (lower limbs strength training); POS SSG (after small sided games); POS ST (after strength training); PRE ST (before strength training); TOTAL (upper and lower limbs strength training); UPPER (upper limbs strength training). ......................................................................................................................... 96 Figure 3.3. Results from interaction Players x Strength Training x Time for abalakov jump values. Legend: LOWER (lower limbs strength training); POS SSG (after small sided games); POS ST (after strength training); PRE ST (before strength training); TOTAL (upper and lower limbs strength training); UPPER (upper limbs strength training). ......................................................................................................................... 97 Figure 3.4. Percentage (%) of the height variation from the baseline (PRE ST) to the interaction Players x Strength Training x Time.............................................................. 98 Figure 4.1. Results from distance covered for each speed zone (a), time spent in each heart rate zone (b), number of impacts for each intensity zone (c) and distance in different intensity zones for each 100m covered at very low intensity (d). ................. 115 Figure 5.1. Distribution (%) of players in each cluster considering the players’ development stage and playing position ....................................................................... 131 Figure 5.2. Results from distance covered for each speed zone (i), number of impacts for each intensity zone (ii) time spent in each heart rate zone (iii) and predictor importance to all considered variable (iv). Significant differences are identified as: (a) Cluster 1 vs. Cluster 2; (b) Cluster 1 vs. Cluster 3; (c) Cluster 2 vs. Cluster 3 ............ 132 Figura 6.1. Representação esquemática das principais aplicações práticas (resultados do presente trabalho).………………………………………………………………….....144 xxii Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ CAPÍTULO 1 23 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 1.1. INTRODUÇÃO 1.1.1. A complexidade nos jogos desportivos coletivos A essência dos jogos desportivos coletivos (JDC) consiste na imprevisibilidade dos seus acontecimentos (Glazier, 2010), resultado do grande número de possibilidades de escolha no decurso de cada jogo, que são únicas e exigem uma adaptação constante dos jogadores e das equipas. O número de jogadores, as relações que se estabelecem entre eles, a diversidade de opções que cada um pode tomar e a sua incerteza comportamental contribuem para que a natureza dos JDC seja complexa (Balague, Torrents, Hristovski, Davids, & Araujo, 2013). A complexidade pode ser entendida como uma medida de número de possibilidades (Bar-Yam, 2003), que no âmbito técnico, tático, físico, psicológico e social dos JDC se interligam mutuamente (Volossovitch, Dumangane, & Rosati, 2010). Assim, a complexidade faz apelo à estratégia, ou seja, à arte de utilizar informações que surgem durante a ação, integrá-las e formular esquemas capazes de reunir o máximo de certezas para defrontar o incerto (Morin, 1992). Apesar do equilíbrio, desequilíbrio, organização, interação e a incerteza serem características da complexidade, esta não significa obrigatoriamente desordem (Volossovitch et al., 2010). Um dos princípios da complexidade, o da auto-organização, descreve que todos os seres vivos são sistemas dotados de grande complexidade, fruto da riqueza de interações entre as suas partes constituintes (Bauer, 1999). Este princípio sublinha que tais sistemas são capazes de resistir às perturbações externas e tirar partido delas para aprenderem e se reorganizarem (Duarte, Araújo, Correia, & Davids, 2012). No âmbito dos JDC, os jogadores deverão ser capazes de gerir a desordem resultante dos constrangimentos decorrentes do jogo, de se adaptar e auto-organizar de forma dinâmica (McGarry, Anderson, Wallace, Hughes, & Franks, 2002), tomando decisões adequadas às circunstâncias vigentes e que respeitem o ambiente que as envolve (Bauer, 1999). Assim, a performance nos JDC deve ser o resultado de um processo de treino a longo prazo que prepare os jogadores para a complexidade que a competição exige (Sampaio & Maçãs, 2012). Mais, o treino deve estar direcionado para as ações funcionais, ajustadas ao contexto e orientadas para um objetivo, devendo ser mais caracterizadas pela eficácia do que pela sua estética (Araujo, Travassos, & Vilar, 2010). 24 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Toda a complexidade do processo de jogo pode ser confundida com o comportamento caótico, que é caracterizado pela sensibilidade às condições iniciais e às pequenas perturbações. Na sua essência, caos refere-se ao fenómeno a partir do qual os sistemas compostos por partes que se relacionam, cada uma das quais com as suas próprias regras de comportamento, podem gerar interações e efeitos não lineares e de certa forma imprevisíveis (Holbrook, 2003). Assim, o comportamento de um sistema é altamente influenciado por variações mínimas que podem ocorrer no seu estado inicial, tornandose o seu desfecho impossível de prever (Gleick, 1987). A título de exemplo prático: um guarda-redes de Andebol ou Futebol pode optar por fazer a reposição de bola para o jogador A ou B. A decisão de passar a bola para o jogador A pode hipoteticamente determinar o sucesso na concretização do processo ofensivo, que por sua vez pode significar a vitória no jogo, a conquista do campeonato e o apuramento para uma competição internacional. Por outro lado, o passe para o jogador B poderia resultar na perda de posse de bola e consequente insucesso. O jogo traduz-se numa sequência de eventos organizada de forma catastrófica e que oscila entre períodos de relativa estabilidade e previsibilidade e acontecimentos casuísticos geradores de desequilíbrios e do imprevisto (Volossovitch et al., 2010). Como consequência, o jogo deve ser interpretado de forma dinâmica e auto-organizada para que se percebam os comportamentos emergentes dos jogadores inseridos num ambiente ecológico (Gonçalves, Figueira, Maçãs, & Sampaio, 2013). Desta forma, a análise das interações entre os jogadores e a identificação dos padrões de jogo emergentes poderão preservar a normal sequência do jogo (Vilar, Araújo, Davids, & Button, 2012). 1.1.2. Modificar o contexto para otimizar a aprendizagem O processo de aquisição de skills motores e desportivos tem sido alvo de várias abordagens teóricas. As teorias mais analíticas estão direcionadas para a psicologia cognitiva e defendem que a prática repetida ao longo do tempo leva à memorização de padrões motores estanques (Davids, Araújo, & Shuttleworth, 2005). Por exemplo, a teoria do processamento de informação defende que a regulação das ações reside na existência de programas motores genéricos armazenados no sistema nervoso que especificam o modelo ideal de execução (Temprado & Laurent, 1999). Ao atribuir 25 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ grande importância aos processos internos do sujeito, a teoria do processamento de informação desloca o problema da tomada de decisão para uma estrutura interna pré existente e negligencia o ambiente que envolve a tomada de decisão do jogador (Araujo, Davids, & Serpa, 2005). Assim, o controlo da ação deve ser percetivo e não assente numa elevada complexidade de processos computacionais ou da memória (Shaw, 2003). É neste âmbito que surge a perspetiva eco-dinâmica da aprendizagem, que refuta os modelos tradicionais e defende que as ações não são impostas por uma estrutura pré-existente, mas residem no sistema sujeito-ambiente (Gibson, 1979). De entre os vários fatores capazes de influenciar o comportamento do sujeito nesse ambiente, destacam-se a estrutura e a física do envolvimento, a biomecânica do corpo de cada indivíduo, a informação percetual relativa às variáveis informacionais e as exigências específicas de cada tarefa (Warren, 2006) (ver figura 1.1). Assim, os desportistas peritos distinguem-se pela capacidade de encontrar as informações que, de acordo com as várias possibilidades, lhes permitem atingir o seu objetivo (Araujo et al., 2005). Figura 1.1. Modelo de interação de constrangimentos (Newell, 1986). No entanto, a perspetiva eco-dinâmica não deve ser considerada de forma isolada (Araujo et al., 2010), uma vez que determinados padrões coordenados podem emergir entre as partes do sistema de movimento dinâmico através de um processo de auto organização (Davids, Button, Araujo, Renshaw, & Hristovski, 2006). O processo de treino não deve ser caracterizado por estímulos e respostas constrangidas por regras prédefinidas cognitivamente pelo jogador, mas sim pela organização funcional de atividades práticas (Araujo, Davids, & Hristovski, 2006). Cabe assim ao treinador perceber quais os constrangimentos mais adequados a cada situação e de que forma é 26 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ que eles influenciam essa organização funcional (Passos, Araujo, Davids, & Shuttleworth, 2008). Durante as sessões de treino, os treinadores podem e devem recorrer a múltiplos parâmetros de ensino que proporcionem a prática de diferentes movimentos e permitam aos jogadores criarem uma base de experiências que os possa ajudar a construir variados esquemas de comportamentos (Schmidt & Lee, 1999). No treino de remate de Andebol, por exemplo, os esquemas utilizados devem incluir o maior número possível de combinações que exijam mudanças em vários comportamentos com vista à otimização do gesto técnico (Wagner & Muller, 2008). Respeitando este princípio, o jogador assimila informação que o ajudará a alterar e ajustar os seus comportamentos em função de diferentes condições e contextos. No caso particular do remate no Andebol, os pressupostos para o desenvolvimento deste gesto técnico sugerem que o treino deve variar parâmetros como velocidade de execução, ponto de largada da bola, ângulo do braço no remate e facilitação ou handicap da impulsão vertical (Roth, 1989). Assim como no futebol, onde manipular e constranger gestos técnicos como receção, drible e remate já mostrou ser benéfico na não-linearidade da aprendizagem e na criação de padrões de movimentos funcionais durante a prática (Schöllhorn, Hegen, & Davids, 2012). A manipulação destes parâmetros torna os sistemas instáveis e fá-los auto organizarem-se (Wagner & Muller, 2008), oferecendo ao sujeito a capacidade de reagir continuamente a novas situações de forma rápida e adequada (Schollhorn, Mayer-Kress, Newell, & Michelbrink, 2009). Neste âmbito, o treino diferencial garante a variabilidade da qualidade e quantidade dos estímulos de exercício para exercício (Schöllhorn et al., 2012), estimulando o jogador a adaptar-se e a criar uma variedade de padrões de comportamento (Frank, Michelbrink, Beckmann, & Schollhorn, 2008). A abordagem diferencial tira partido das flutuações num sistema complexo aumentando-as através de uma “não repetição” e constante mudança nas tarefas, o que acrescenta perturbações estocásticas (Schöllhorn et al., 2012). Assim, as flutuações nos subsistemas do sujeito são exploradas mesmo durante a aprendizagem, aportando-lhe a capacidade de ele próprio encontrar padrões de performance dependentes do contexto em que está inserido (Frank et al., 2008). Baseados nestes pressupostos, os jogos reduzidos (JR) assumem-se como uma ferramenta útil no processo de treino, permitindo ao treinador manipular uma série de variáveis que influenciam os estímulos dos exercícios, tais como a área de jogo, número 27 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ de jogadores, feedback do técnico, regime intervalado ou contínuo, regras e uso de guarda-redes (Hill-Haas, Dawson, Impellizzeri, & Coutts, 2011). As vastas possibilidades de constrangimentos aplicados aos JR facilitam o desenvolvimento de habilidades técnico-táticas e melhoria da capacidade física em contexto apropriado de jogo (Little, 2009). 1.1.3. Como contemplar a complexidade no treino dos jogos desportivos coletivos? As abordagens teóricas ao treino dos JDC têm sofrido alguns avanços que se opõem aos modelos mais clássicos, que privilegiavam a simplificação do jogo em elementos isolados, que desconsideravam a sua totalidade complexa e desrespeitavam as suas inter-relações (Reverdito & Scaglia, 2007). Os JDC são férteis em acontecimentos cuja complexidade não pode ser prevista antecipadamente, exigindo aos jogadores uma predisposição estratégica e tática permanentes (McGarry, 2009). Assim, a definição de objetivos e seleção de exercícios para o treino não deverá ir de encontro à automatização do gesto através de repetições indeterminadas, porque embora o jogador possa ir ajustando a execução desse mesmo gesto, não terá um suporte motor suficientemente amplo para dar a resposta ideal numa qualquer situação competitiva, que nunca se repete da mesma maneira (Schollhorn et al., 2009). Para que os jogadores desenvolvam os seus processos cognitivos e sejam capazes de se adaptar aos diversos cenários competitivos, é necessário atribuir estímulos variados no treino (ver figura 1.2) em que o jogador procure a resposta ideal de acordo com o contexto e as suas características (Fajardo, 1999). Figura 1.2. Aspetos do treino cognitivo a considerar para a construção de tarefas de treino (Fajardo, 1999). 28 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Uma vez que a competição obriga os jogadores a tomar decisões enquanto executam ações intensas, a procura do rendimento ótimo exige cargas de treino específicas de intensidade elevada, variadas e que se manifestem em curtos espaços de tempo (Tenenbaum, LevyKolker, Sade, Liebermann, & Lidor, 1996). Num âmbito mais específico do treino de força (TF), por exemplo, o treino deverá incluir tarefas que impliquem tomadas de decisão características da modalidade (Fajardo, 1999) (ver figura 1.3). Figura 1.3. Exemplo de um exercício que contempla a colaboração e oposição característica dos desportos de equipa. Em função da atuação do defensor, o atacante deve escolher entre o lançamento ou progressão com bola (Fajardo, 1999). Na verdade, o próprio estímulo fisiológico poderá ser manipulado para que a resposta motora não seja previamente idealizada e processada pelo executante. Assim, para além da complexidade na tomada de decisão técnico-tática, também a tarefa de força específica pode ser constrangida para replicar o estímulo fisiológico imprevisível que caracteriza todas as ações de cooperação-oposição em jogo. http://www.youtube.com/watch?v=M7aFrylaCvY&feature=youtu.be 29 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Numa dimensão técnico-táctica deve-se privilegiar o jogo como elemento fundamental e recorrer à sua problematização, o que poderá ser feito a partir da manipulação da sua estrutura organizacional, ou seja, de variáveis como as dimensões do terreno de jogo, o número de jogadores e as regras (Hill-Haas et al., 2011). 1.1.4. Dimensões dos jogos reduzidos Algumas características dos JDC como a variabilidade e a imprevisibilidade têm sido utilizadas com recurso a exercícios específicos que visam determinadas condicionantes que integram as variáveis do jogo. Os JR são habitualmente praticados em áreas reduzidas, envolvem um número reduzido de jogadores e utilizam regras modificadas (Hill-Haas et al., 2011). Uma vez que este tipo de jogos permite a manipulação de variáveis que podem influenciar a intensidade do exercício e replicar as exigências competitivas, o aumento da produção científica centrada no estudo dos JR pode contribuir para uma análise mais detalhada das principais dimensões do jogo: técnicotática, fisiológica e psicológica. Relativamente à dimensão técnico-tática, os JR facilitam a assimilação de conceitos técnicos, táticos individuais e táticos coletivos (Owen, 2003). Numa perspetiva de treino no alto rendimento, é importante decompor o jogo através do uso de diferentes formatos de JR com alteração do número de participantes (Rampinini, Impellizzeri, Castagna, Abt, Chamari, Sassi, et al., 2007). De um modo geral, as formas de jogo mais reduzidas permitem aos jogadores contactos mais frequentes com a bola em diferentes situações de jogo, o que requer a utilização de habilidades técnico-táticas ajustadas ao contexto (Capranica, Tessitore, Guidetti, & Figura, 2001). Numa dimensão fisiológica, a prática dos JR pode ser usada como uma ferramenta para a melhoria da condição física, uma vez que induz níveis de frequência cardíaca (FC) próximos dos 90 a 95% da FC máxima (Hoff, Wisloff, Engen, Kemi, & Helgerud, 2002). Estas intensidades elevadas favorecem o desenvolvimento da performance aeróbia (Helgerud, Engen, Wisloff, & Hoff, 2001), indo de encontro a valores já verificados em algumas formas de treino intervalado (Impellizzeri, Marcora, Castagna, Reilly, Sassi, Iaia, et al., 2006). Na verdade, os benefícios obtidos no treino são máximos quando a intensidade utilizada é similar aquela que se verifica em competição (Mallo & Navarro, 2008). Adicionalmente, a inclusão de JR nos programas de treino 30 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ promove respostas e intensidades neuromusculares específicas da modalidade, para além de aumentar a motivação para realizar as tarefas (Hill-Haas et al., 2011). Vários estudos sugerem que a resposta fisiológica é afetada pela alteração de algumas condicionantes do jogo (Fanchini, Azzalin, Castagna, Schena, McCall, & Impellizzeri, 2011a; Kelly & Drust, 2009; Sampaio, García, Maçãs, Ibáñez, Abrantes, & Caixinha, 2007). A duração, tempos de descanso, o número de jogadores, dimensões do terreno, alteração de regras e feedback por parte do técnico têm um impacto direto sobre os fatores fisiológicos e psicofisiológicos, refletidos pelos valores de FC e perceção subjetiva de esforço (PSE1) (Hill-Haas et al., 2011), respetivamente. A avaliação sistemática destes parâmetros, em conjunto com as ações técnicas e táticas (ATT), pode contribuir para a obtenção de resultados válidos e mais fiáveis, melhorando significativamente o processo de treino (Tessitore, Meeusen, Piacentini, Demarie, & Capranica, 2006). A investigação centrada na manipulação de variáveis e o seu efeito na resposta fisiológica, psicológica e técnico-tática em JR é abundante no futebol, mas praticamente omissa no Andebol. Apesar disso, a utilização de JR no Andebol parece contribuir para o desenvolvimento da capacidade aeróbia em contexto de jogo, preservando componentes específicos da modalidade como a agilidade, tempos de reação e coordenação óculo-manual (Buchheit, Laursen, Kuhnle, Ruch, Renaud, & Ahmaidi, 2009). Apesar dos JR permitirem uma reprodução fiel do padrão cardiovascular e técnicotático necessário à preparação desportiva dos jogadores (Reilly & White, 2004), replicar o padrão de solicitação muscular parece bem mais complexo. Para que as adaptações da força sejam significativas, tanto a nível morfológico como neuromuscular, são necessários programas de treino que respeitem metodologias específicas. Por exemplo, para o aumento da massa muscular são necessárias intensidades próximas de 70 a 80% de uma repetição máxima (Moore, Burgomaster, Schofield, Gibala, Sale, & Phillips, 2004), enquanto as adaptações neurais requerem intensidades entre 90 a 100% de uma repetição máxima (Takarada, Takazawa, Sato, Takebayashi, Tanaka, & Ishii, 2000). 1 A PSE é um método de avaliação psico-fisiológico da intensidade percebida do esforço, desenvolvido no início dos anos 60 por Gunnar Borg. Este autor desenvolveu a escala da percepção subjectiva de esforço, considerada fiável e de fácil compreensão, que tem sido aplicada na monitorização do exercício em populações adultas (ver Borg, 1990 e 1998; Faulkner & Eston, 2008). 31 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 1.1.4.1. Dimensão muscular Ao contrário do que acontece com a aptidão cardiovascular e ATT, a força muscular não é suficientemente solicitada através da prática dos JR. Esta ideia é suportada pela relação entre a PSE e as concentrações de lactato sanguíneo já investigada (Aroso, Rebelo, & Gomes Pereira, 2004). Neste estudo verificaram-se concentrações de lactato de 4.9±2.0 e 2.6±1.7 (mmol/L) e valores de PSE de 14.5±1.7 e 13.3±0.9 em jogo 3x3 e 4x4, respetivamente (Aroso et al., 2004). Assim, diferentes formatos de JR induziram valores elevados de PSE mas não de lactato sanguíneo, o que sugere uma perceção elevada da intensidade do esforço que não foi correspondida por uma solicitação muscular significativa. Como já foi referido, adaptações musculares significativas exigem cargas específicas, só possíveis com recurso a unidades especiais de TF (Zatsiorsky & Kraemer, 2006). Neste sentido, torna-se importante perceber os efeitos da interação entre as unidades de TF e as unidades de treino de pavilhão, procurando obter modelos de periodização que permitam a sua concorrência e produzam melhorias na performance. O TF é essencial para se atingir elevadas performances durante a competição. Na verdade, os objetivos finais do TF passam por aumentar a força e/ou assegurar a sua conservação nos diferentes períodos do ciclo anual de treino, atingir um desenvolvimento harmonioso de todos os grupos musculares (Zatsiorsky & Kraemer, 2006) e alcançar elevados índices de força e potência nos movimentos que caracterizam cada uma das modalidades (Verkhoshansky, 2006). Em suma, o potencial de força deve ser manifestado com base no princípio da conjugação de ações, ou seja, melhoria da capacidade física funcional e habilidades técnico-táticas (Verkhoshansky, 2006). O Andebol é um jogo caracterizado por movimentos complexos com e sem bola, executados em regimes variáveis de velocidade e força como acelerações repetidas, sprints, saltos, mudanças de direção e contacto físico entre jogadores (Ronglan, Raastad, & Borgesen, 2006). A necessidade que o jogador de Andebol tem de realizar ações de curta duração a alta intensidade reforça o TF como uma ferramenta indispensável à melhoria da sua performance, ajudando-o na execução de tarefas de competição que implicam níveis elevados de força aliados a velocidades de execução rápidas (Ziv & Lidor, 2009). Partindo destes pressupostos e considerando que adaptações significativas de força exigem sessões de treino específicas, parece evidente 32 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ que a concorrência entre as unidades de TF e as unidades de treino de pavilhão deve ser cuidadosamente manipulada na periodização e planeamento do treino. Já foi demonstrado que a adição de sessões específicas de TF máxima ao treino técnicotático de Andebol resulta em ganhos maximais de força e aumento da velocidade de remate, embora possa comprometer ganhos de força explosiva nos membros inferiores e resistência de corrida (Gorostiaga, Izquierdo, Iturralde, Ruesta, & Ibanez, 1999). Aparentemente, o treino conjunto de força máxima e resistência pode inibir a médio prazo capacidade de produzir força (Hickson, 1980), provavelmente pela dificuldade de adaptação da estrutura muscular ao treino combinado (Zatsiorsky & Kraemer, 2006). Figura 1.4. Mudanças na resposta da capacidade força em 3 tipos de treino. Os registos dos grupos do treino de força e treino de força + resistência foram semanais. O grupo do treino de resistência foi avaliado no início e final do protocolo (Hickson, 1980). No entanto, já foram relatados ganhos em ambas as capacidades quando a força foi treinada separadamente da resistência (Collins & Snow, 1993; Leveritt & Abernethy, 1999). Neste sentido, sugere-se que o treino concorrente de força e resistência pode resultar em ganhos para ambas as capacidades, desde que os mecanismos de recuperação sejam respeitados (Wong, Chaouachi, Chamari, Dellal, & Wisloff, 2010). Apesar destes resultados, o conhecimento acerca da ordem com que se treina a força e resistência é ainda escasso. Para além disso, a literatura é pobre no que diz respeito aos efeitos imediatos que TF tem na performance técnico-tática dos jogadores. 33 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ A magnitude e a fonte de fadiga no TF podem variar de acordo com o tipo de contração muscular (Babault, Desbrosses, Fabre, Michaut, & Pousson, 2006), intensidade (Linnamo, Newton, Hakkinen, Komi, Davie, McGuigan, et al., 2000), velocidade de execução (Linnamo, Hakkinen, & Komi, 1998) e tempo de descanso (Pattersson, Pearson, & Fisher, 1985). Neste sentido, importa perceber quais as adaptações agudas e crónicas induzidas pelo TF, para que a seleção da localização das sessões nos microciclos e mesociclos de treino seja criteriosa e salvaguarde uma metodologia eficiente. Em relação às adaptações crónicas, o treino de hipertrofia, caracterizado por intensidades próximas das 10 repetições máximas (Kraemer, Marchitelli, Gordon, Harman, Dziados, Mello, et al., 1990), promove alterações morfológicas como o aumento da secção transversal do músculo (Moore et al., 2004) e facilita o aumento da força muscular (Verkhoshansky, 2006). Contudo, a capacidade de gerar força depende igualmente das adaptações do sistema nervoso. Assim, o treino de adaptações neurais requer intensidades próximas dos 90% de uma repetição máxima, para que haja um maior recrutamento de fibras musculares (Takarada et al., 2000) e melhor sincronização entre as unidades motoras responsáveis pelo mecanismo de contração muscular (Fajardo, 1999). Neste sentido, a combinação entre o aumento da massa muscular e o trabalho de natureza neural é fundamental para que o desenvolvimento da capacidade força seja significativo. Quando comparadas no tempo, as adaptações induzidas pelos programas de hipertrofia são mais lentas e tardias do que as verificadas no treino neural (Sale, 1988). Por esse motivo, as adaptações hipertróficas requerem um maior número de unidades de treino. Apesar destas investigações sublinharem importantes adaptações crónicas ao TF, os efeitos agudos que estes programas de treino induzem na performance dos jogadores de Andebol são pouco explorados na literatura. Esta escassez de informação dificulta a tarefa dos treinadores na organização semanal do processo de treino que inclua sessões de TF combinadas com sessões de treino técnicotático. No entanto, existem estudos focados nos efeitos neuromusculares agudos do TF máxima que podem ajudar a perceber algumas variações nos perfis de desempenho dos jogadores imediatamente após uma sessão de TF (Babault et al., 2006; Bigland-Ritchie, 1981; McCaulley, McBride, Cormie, Hudson, Nuzzo, Quindry, et al., 2009; Moore et al., 2004; Sale, 1992). 34 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Os períodos curtos de recuperação no treino de hipertrofia parecem aumentar o recrutamento de unidades motoras, apesar do decréscimo da capacidade de gerar força (Sale, 1992), consequência da fadiga de origem periférica (Moore et al., 2004). Contrariamente ao treino hipertrófico, a fonte de fadiga observada nos protocolos neurais parece estar associada a uma falha na ativação do sistema nervoso central (McCaulley et al., 2009), resultando na diminuição da atividade muscular e deterioração da produção de força (Bigland-Ritchie, 1981). Para além disso, o treino neural induz concentrações de lactato significativamente inferiores aos protocolos de hipertrofia, muito em parte devido aos intervalos de recuperação prolongados entre séries (McCaulley et al., 2009). Imediatamente após a realização do TF, os protocolos neurais parecem estimular grande parte das fibras tipo II (Sale, 1992), enquanto os protocolos de hipertrofia resultam num decréscimo do peak force e capacidade de gerar força, aumentando no entanto a atividade elétrica dos músculos (McCaulley et al., 2009). Este fenómeno é conhecido por ineficiência neuromuscular (Deschenes, Judelson, Kraemer, Meskaitis, Volek, Nindl, et al., 2000) e pode ser um forte sinal de fadiga periférica (Babault et al., 2006). Para além destes indicadores, também já foi observado que os processos de recuperação da capacidade de gerar força (24h e 48h) foram mais rápidos após um protocolo de hipertrofia do que o verificado no neural (McCaulley et al., 2009). Em suma, tanto os treinos neural como o hipertrófico resultam em fadiga neuromuscular, provavelmente com origem em diferentes fontes, central e periférica respetivamente. Quando comparados com outas metodologias de TF, os protocolos de hipertrofia e adaptações neurais promovem efeitos imediatos na diminuição do percentual do peak force isométrico e uma quebra na capacidade de gerar força, enquanto, por exemplo, os treinos de resistência e potência não são capazes de induzir alterações significativas (McCaulley et al., 2009). Apesar destas informações poderem e deverem ser consideradas na prescrição de um plano de treino, já foi sublinhada a escassez de investigação científica focada nos efeitos agudos do TF nas ações desportivas do jogador de Andebol. O lapso que a literatura apresenta neste domínio faz com que os técnicos de Andebol não possuam informação suficiente e válida que lhes permita identificar os momentos mais adequados para a inclusão do TF no microciclo e/ou unidades de treino. 35 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 1.1.4.2. Dimensão energética São várias as investigações que se têm focado nas respostas fisiológicas agudas a JR e formas intervaladas de treino (Balsom, Gaitanos, Soderlund, & Ekblom, 1999; Dellal, Chamari, Pintus, Girard, Cotte, & Keller, 2008; Sassi, Reilly, & Impellizzeri, 2004). Considerando durações de exercício idênticas, as conclusões desses estudos apontam para a existência de intensidades semelhantes em ambos os formatos. Para além disso, já se verificaram adaptações semelhantes ao nível da capacidade aeróbia e realização de exercícios intermitentes com mudanças de direção após um programa de treino de 6 semanas que contemplou JR e regimes de treino intervalado (Reilly & White, 2004). No entanto, a variabilidade dos estímulos parece ser superior nos JR em comparação com os exercícios intervalados (ver figura 1.5), provavelmente pela natureza específica das ações inerentes ao jogo (Hill-Haas et al., 2011). Figura 1.5. Valores médios (%FC máxima) da intensidade do exercício em diferentes situações de treino de futebol (Hill-Haas et al., 2011). Aparentemente, tanto os JR como os regimes de treino intervalado são ferramentas úteis para o desenvolvimento da performance aeróbia ao longo da época desportiva. Na verdade, já foi observado que ambos os métodos induziram valores idênticos da %FCmax e PSE após 12 semanas de treino (Impellizzeri et al., 2006). 36 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ A intensidade do esforço em JR tem sido avaliada sobretudo com recurso à análise da FC, lactato sanguíneo e PSE (Hill-Haas et al., 2011). Contudo, a FC parece ser a ferramenta mais privilegiada, sendo considerada um método válido e fiável na avaliação da intensidade do esforço em vários desportos (Achten & Jeukendrup, 2003). Por exemplo, já foi mostrado que a resposta fisiológica é influenciada pela alteração de fatores como a duração do jogo (Duarte, Batalha, Folgado, & Sampaio, 2009), área do campo (Kelly & Drust, 2009), regras do jogo (Hill-Haas, Coutts, Dawson, & Rowsell, 2010) e número de jogadores (Owen, Twist, & Ford, 2004; Sampaio et al., 2007). Mais, a relação entre a média dos valores da FC e do consumo de oxigénio (VO2) detetada em testes laboratoriais é semelhante à relação da FC com o VO2 verificada durante a avaliação do esforço em JR (Esposito, Impellizzeri, Margonato, Vanni, Pizzini, & Veicsteinas, 2004). Apesar da validade desta variável, o tempo exigido para análise e interpretação dos dados pode representar um constrangimento para os treinadores. Também o lactato sanguíneo tem sido utilizado com frequência na avaliação da intensidade esforço, no entanto é considerado um indicador pobre das concentrações de lactato muscular em atividades de carácter intermitente (Krustrup, Mohr, Steensberg, Bencke, Kjaer, & Bangsbo, 2006). Deste modo, a PSE apresenta-se como um método simples, não invasivo e sem custos para a monitorização da intensidade do exercício (Borg, 1982). O uso da PSE surge assim como uma alternativa válida para quantificar a intensidade do esforço durante uma sessão de treino (Impellizzeri, Rampinini, Coutts, Sassi, & Marcora, 2004a). A PSE pode ser definida como a intensidade subjetiva de esforço, desconforto e/ou fadiga sentida durante a realização de um exercício físico (Robertson, 2001). A interpretação fisiológica dos aspetos cardiorrespiratórios, metabólicos e musculares tem um papel importante na regulação da intensidade do exercício. No entanto, a atividade desportiva não possui apenas uma componente física. A PSE tem uma natureza multifatorial que não é mediada apenas por fatores fisiológicos mas também por fatores psicológicos (Borg, 1982). Neste sentido, a PSE é considerada um indicador psicofisiológico para a obtenção do grau do esforço físico, integrando informações como sinais deduzidos do trabalho muscular, cardiopulmonar e do sistema nervoso central (Robertson, 2000). Para além disso, tem-se mostrado um método simples e válido na quantificação da intensidade de sessões de treino, quer em esforços de carácter 37 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ contínuo (Foster, Florhaug, Franklin, Gottschall, Hrovatin, Parker, et al., 2001) como em esforços intermitentes (Impellizzeri et al., 2004a). A avaliação da PSE foi já sugerida como um método mais apropriado na avaliação da intensidade do esforço do que a análise individualizada das variáveis fisiológicas (Borg, 1982). No entanto, é necessário integrar as informações obtidas a partir dos três diferentes tipos de variáveis de esforço - performance/rendimento, avaliações fisiológicas e respostas de perceção para que os resultados obtidos sejam mais fiáveis. Aparentemente existe uma relação forte entre as estimativas do esforço percebido e as concentrações de lactato, o que sugere que o aumento da PSE pode estar relacionado com o aumento da FC e lactato sanguíneo (Borg, Hassmen, & Lagerstrom, 1987). Na verdade, já foi demonstrado que a combinação dos dados obtidos pela avaliação da FC e concentração de lactato no sangue com a PSE apresentou resultados mais fiáveis do que a análise isolada da FC ou concentração de lactato (Chen, Fan, & Moe, 2002). Em suma, a PSE está correlacionada com muitas formas de avaliação da intensidade do exercício, como o consumo de oxigénio, ventilação, frequência respiratória, concentração de lactato no sangue e FC (Faulkner & Eston, 2008). Em conjunto, todos estes fatores parecem suportar a PSE como um método fiável na avaliação da intensidade em esforços intermitentes, os de manifestação mais frequente nos JDC. No entanto, não existe nenhuma evidência que permita afirmar que um método de avaliação é mais fiável do que outro, pelo que a monitorização da intensidade nos JR deve ser feita através da combinação de métodos (Coutts, Rampinini, Marcora, Castagna, & Impellizzeri, 2009). Compreender os efeitos que os vários fatores externos têm na intensidade do esforço e performance técnico-tática pode permitir uma melhor integração dos JR no processo de treino (Fanchini, Azzalin, Castagna, Schena, Mccall, & Impellizzeri, 2011b). Neste contexto, a análise do comportamento dos jogadores e das equipas torna-se preponderante na avaliação, organização e prescrição do treino. 1.1.4.3. Dimensão técnico-tática O carácter complexo e multidimensional dos JDC apresenta constrangimentos na análise do rendimento desportivo, sobretudo porque o seu produto final é influenciado por fatores físicos, psíquicos e técnico-táticos (Glazier, 2010). Segundo a teoria das 38 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ performances interativas, a performance de uma equipa é afetada pela qualidade e tipo de oposição, para além de diferentes jogadores serem influenciados pelo mesmo tipo de oposição de forma distinta (O'Donoghue, 2009). Deste modo, a relação das equipas com os jogadores adversários torna-se um fator chave na interpretação dos comportamentos durante o jogo (McGarry, 2009). Todas estas interações fazem com que a performance desportiva não possa ser avaliada com recurso a dados isolados, sendo necessária uma abordagem combinada (ver figura 1.6) que considere a complexidade dos sistemas (Hughes & Franks, 2004). Figura 1.6. Abordagem a sistemas complexos utilizada para análise da performance desportiva (Hughes & Franks, 2004). Apesar das estatísticas do jogo captarem detalhadamente o que se passa em jogo (Sampaio, Ibanez, Feu, Lorenzo, Gomez, & Ortega, 2008), a investigação científica atual acrescenta a necessidade de criar modelos multidimensionais para o estudo de sistemas complexos. A análise da performance deve considerar fatores como o processo e o resultado (ver figura 1.7), ou seja, a descrição das condutas dos jogadores e sua 39 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ eficácia no tempo, bem como o resultado final da interação entre as equipas (Grehaigne & Godbout, 1995). Por exemplo, o enquadramento temporal das ações registadas pode contemplar o equilíbrio do resultado e as condutas do adversário, para que a perspetiva global do jogo se rega pelo princípio de que os elementos não têm significado, senão na sua relação com o conjunto (Volossovitch, 2008). Deste modo, a análise do jogo deve respeitar uma abordagem dinâmica que interprete a sua realidade complexa (Bar-Yam, 2003). Figura 1.7. Duas dimensões da análise do jogo (Volossovitch, 2008). No Andebol, a performance tem sido avaliada com recurso a indicadores como remates concretizados e falhados da zona dos 9m, da zona dos 6m (pivot e extremos) e em contra-ataque, assistências, livres de 7 metros conquistados, falhas técnicas no ataque e diferença entre golos marcados e sofridos (Gruić, Vuleta, & Milanović, 2006; Ohnjec, Vuleta, Milanovic, & Gruic, 2008). Outros indicadores como a eficácia dos guardaredes, ações defensivas e eficácia do remate em ataque organizado (Magalhães, 1999) também já foram utilizados com o objetivo de definir indicadores que associassem a performance à classificação final de provas oficiais da modalidade. Em conjunto com as habilidades técnico-táticas, a performance do remate também tem sido referida como um parâmetro chave para o sucesso no Andebol (Hoff & Almasbalck, 1995). Nesse sentido, a precisão do gesto técnico e a velocidade da bola são consideradas variáveis decisivas para o sucesso do remate (Fleck, Smith, Craib, Denahan, Snow, & Mitchell, 1992). O resultado da combinação entre a precisão e velocidade do gesto define a eficácia do remate, que é determinada sobretudo por fatores coordenativos, mecânicos e pela força dos membros superiores e inferiores (Fleck et al., 1992; Gorostiaga, Granados, Ibanez, & Izquierdo, 2005). 40 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Torna-se evidente que a diversidade de ações que caracteriza o Andebol requer preparação específica da força (Boraczynski & Urniaz, 2008), uma vez que o treino desta capacidade tem um impacto significativo na execução de ações fundamentais no jogo como o sprint e impulsão vertical máxima (Ronglan et al., 2006). O TF com intensidades elevadas responde à necessidade de produzir níveis elevados de força em curtos espaços de tempo (Zatsiorsky & Kraemer, 2006) e à máxima velocidade de execução (Harris, Stone, O’Bryant, Proulx, & Johnson, 2000), indo de encontro aos requisitos do jogo de andebol (Rannou, Prioux, Zouhal, Gratas-Delamarche, & Delamarche, 2001). No entanto, uma vez que a execução técnica é uma peça chave para a otimização dos resultados desportivos, o TF deve englobar exercícios que reflitam o conjunto de ações motoras, gestos técnicos e grupos musculares mais solicitados na modalidade (Marques & Gonzalez-Badillo, 2006). Para além disso, o TF deve respeitar velocidades, acelerações e amplitudes gestuais idênticas às dos gestos competitivos específicos (Verkhoshansky, 2006). Em síntese, a performance desportiva é influenciada pelas capacidades técnicas, táticas e físicas, cabendo aos técnicos a sua inclusão e organização no processo de treino (Jones & Drust, 2007). Neste âmbito, os JR são reconhecidos como uma estratégia eficiente para aumentar o tempo de prática efetiva dos jogadores, solicitando em simultâneo as habilidades técnicas, táticas e capacidades físicas (Rampinini, Impellizzeri, et al., 2007). Ao contrário do que acontece nos exercícios de corrida, a presença de bola nos JR parece facilitar o desenvolvimento das habilidades técnico-táticas em contexto de jogo, uma vez que permite a replicação de movimentos específicos, intensidades e requisitos técnicos da competição (Gamble, 2004; Little, 2009). As situações de JR aumentam a frequência e exigência das ATT (Jones & Drust, 2007), verificando-se um aumento do número de ações nos formatos de jogo com menor número de jogadores (Hill-Haas et al., 2011). No caso particular do Andebol, os formatos de jogo reduzido parecem aumentar a frequência individual de passes, receções, remates, desmarcações e interceções em idades jovens (Ribeiro & Volossovitch, 2004). 41 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Figura 1.8. Média ± SD de contactos com a bola em jogo 4x4 e 8x8 de futebol (Jones & Drust, 2007). * Diferenças estatisticamente significativas. No entanto, a frequência das ATT não pode considerada de forma isolada na avaliação da performance de uma equipa, uma vez que o principal objetivo dos JDC deve estar direcionado para as ações funcionais, ou seja, para a eficácia das ações (Araujo et al., 2006). No futebol, a comparação de formatos de JR 4x4 e 6x6 mostrou que apesar de ter sido previsível observar um maior número de ATT no jogo 4x4, a alteração do número de jogadores não influenciou significativamente a eficácia das ações (Abrantes, Nunes, Macas, Leite, & Sampaio, 2012). Estes resultados sugerem a realização de investigações futuras que esclareçam a relação entre a manipulação de constrangimentos da tarefa e a eficácia das ações. Para isso, é importante não descurar que os modelos de eficácia são diferentes em cada equipa e em cada jogo, influenciados em parte pelo tipo de oposição, interação entre jogadores e sistemas utilizados nos processos defensivo e ofensivo (Vuleta, Milanović, Gruić, & Ohnjec, 2005). Só assim é que o jogo poderá ser analisado através de uma abordagem dinâmica que considere o processo e contexto em que os jogadores estão envolvidos. A importância demonstrada que o TF e a os JR têm no processo de treino de Andebol acentua a necessidade de investigar os efeitos que a inclusão de ambos tem na performance dos jogadores. Em particular, o TF com cargas elevadas está associado ao declínio da força muscular e a manifestações de fadiga agudas (McCaulley et al., 2009), provocando, por exemplo, a diminuição da eficácia do passe em jogadores de basquetebol na realização de exercícios analíticos (Lyons, Al-Nakeeb, & Nevill, 2006). No entanto, a análise isolada de um exercício ou gesto técnico é insuficiente, uma vez 42 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ que desconsidera a complexidade e o carácter multidimensional do jogo. Deste modo, continuam a ser escassos os dados acerca dos efeitos agudos do TF máxima na performance técnico-tática em contexto de jogo, em particular no Andebol. 1.1.5. Planeamento a curto prazo nos jogos desportivos coletivos 1.1.5.1. Efeitos agudos do treino de força nos perfis de performance de andebolistas O Andebol é uma modalidade dinâmica que requer jogadores velozes, ágeis, resistentes, coordenados e fortes (Hatzimanouil & Oxizoglou, 2004). No caso particular da força muscular, ela é responsável por assegurar o desenvolvimento das propriedades funcionais específicas da modalidade e por promover uma estrutura dinâmica perfeita das ações motoras (Fleck & Kraemer, 2004). Para além disso, a força muscular é um pressuposto fundamental para o desenvolvimento da potência, um dos principais requisitos do rendimento desportivo (Allerheiligen, 1994). Assim, o aumento do potencial motor impõe exercícios de competição, incluindo os de força, combinados com velocidades de execução elevadas (Verkhoshansky, 2006). O aumento na produção de potência é conseguido sobretudo pelo desenvolvimento da capacidade motora, que por sua vez depende do aumento da capacidade dos sistemas do corpo produzirem energia e da perfeição dos skills dos jogadores para aplicarem todo o seu potencial motor em competição (ver figura 1.9). Figura 1.9. Os principais fatores responsáveis por determinar o resultado desportivo (Verkhoshansky, 2006). 43 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Vários estudos demonstram que programas periodizados de TF são determinantes no desenvolvimento de ações motoras como a impulsão vertical (Christou, Smilios, Sotiropoulos, Volaklis, Pilianidis, & Tokmakidis, 2006; Gorostiaga, Izquierdo, Ruesta, Iribarren, Gonzalez-Badillo, & Ibanez, 2004; Luebbers, Potteiger, Hulver, Thyfault, Carper, & Lockwood, 2003), agilidade e velocidade de deslocamento (Christou et al., 2006; McBride, Triplett-McBride, Davie, & Newton, 2002; Miller, Herniman, Ricard, Cheatham, & Michael, 2006). No Andebol, já foi verificado que o TF é preponderante para o aumento da velocidade de remate (Gorostiaga et al., 1999), o que em conjunto com a melhoria das ações acima referidas pressupõe que o desenvolvimento desta capacidade acrescenta a possibilidade de recurso a mais estratégias e táticas por parte dos jogadores. Deste modo, sem negar a importância de outras capacidades físicas, o planeamento do TF assume uma elevada preponderância no progresso desportivo, devendo seguir uma direção lógica para maximizar a performance desportiva (Verkhoshansky, 2006). A importância que cada microciclo de força assume na periodização e planificação do treino varia, principalmente em função de fatores como a frequência do TF, objetivos do TF, intensidade do TF e variabilidade dos exercícios (Badillo, 2000). Com vista à obtenção do máximo rendimento, a distribuição e a carga dos exercícios devem ser parâmetros considerados aquando da prescrição de um programa de TF (Zatsiorsky & Kraemer, 2006). No entanto, outros constrangimentos se emergem, como a localização da unidade de TF no microciclo e o tempo de recuperação entre sessões. Ao contrário do que acontece em modalidades como o halterofilismo e culturismo, no Andebol não se pode considerar a força como única componente do treino, uma vez que a necessidade de desenvolver capacidades como a resistência, velocidade e habilidades técnicas, faz com que o TF se assuma como parte do processo de treino. Assim, é preciso ter em atenção as dificuldades que o organismo pode ter em se adaptar quando as solicitações são múltiplas e em simultâneo, correndo-se o risco de obter modificações insignificantes nas diferentes capacidades motoras (Zatsiorsky & Kraemer, 2006). Neste sentido, os efeitos da fadiga devem ser interpretados e manipulados de forma cautelosa durante o planeamento de curta duração(Hansen, Kvorning, Kjaer, & Sjøgaard, 2001). 44 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ De acordo com o modelo “ dois fatores” (Zatsiorsky & Kraemer, 2006), o efeito agudo do TF resulta da combinação de dois aspetos: ganhos na aptidão física (mudanças lentas na componente motora da performance desportiva) e fadiga (diminuição transitória e reversível da capacidade de trabalho). Após uma unidade de TF, o potencial de performance desportiva de um atleta melhora devido aos ganhos de aptidão física mas deteriora-se devido à fadiga. Assim, o resultado final é o somatório das mudanças positivas e negativas ocorridas neste processo (ver figura 1.10). Figura 1.10. Modelo de treino “dois fatores”. O efeito imediato de uma sessão de TF é caracterizado pelo somatório de dois processos: ganhos na aptidão física e fadiga (Zatsiorsky & Kraemer, 2006). Desta forma, os ganhos de aptidão física resultantes de uma sessão de treino de força são moderados em magnitude mas prolongam-se no tempo, enquanto o efeito da fadiga é superior em magnitude mas relativamente curto em duração. Este é mais um fator a ter em conta no estabelecimento de etapas de TF, exigindo aos técnicos conhecimentos profundos acerca da periodização e planeamento desportivo (Gamble, 2010). A periodização tradicional, caracterizada pela divisão do programa desportivo anual em pequenos períodos e unidades de treino, tem sido limitada por uma série de fatores. De entre eles destacam-se o conflito das respostas fisiológicas produzido pelo treino dirigido a várias capacidades motoras em simultâneo, a fadiga excessiva provocada por longos períodos com múltiplos objetivos de treino, o fraco estímulo induzido por cargas leves/médias e a incapacidade de proporcionar picos de forma ao longo da época (Issurin, 2008). Como consequência, um planeamento baseado no método tradicional 45 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ pode resultar em perdas acentuadas na massa magra (Allerheiligen, 1994), força máxima (Astorino, Tam, Rietschel, Johnson, & Freedman, 2004), potência máxima anaeróbia (Lorenz, Reiman, & Walker, 2010) e até velocidade máxima (Fleck & Kraemer, 2004). Desde logo, a aplicação de um método unidirecional não dá resposta às múltiplas manifestações físicas e técnicas que a performance desportiva na maior parte das modalidades requer (Zatsiorsky & Kraemer, 2006). Num período preparatório, por exemplo, a necessidade de desenvolver a capacidade aeróbia e força muscular oferece limitações à partida, já que são requeridas adaptações específicas a nível fisiológico e morfológico que podem não ser compatíveis se trabalhadas em simultâneo (Issurin, 2008). Já no período competitivo, a periodização tradicional caracteriza-se pelo estabelecimento de dois ou três macrociclos (Platonov, 1997). Mais uma vez, este tipo de organização não satisfaz as exigências dos calendários congestionados que caracterizam o grosso dos desportos coletivos de alto rendimento (Lago-Penas, Rey, Lago-Ballesteros, Casais, & Dominguez, 2011). Durante o período competitivo, os objetivos estão mais relacionados com os aspetos técnico-táticos do que com o TF (Baker, 2007). Por esse motivo, o principal desafio dos técnicos passa por manter os elevados níveis de potência muscular adquiridos durante período preparatório (Porta, Viñaspre, & Morera, 1996). No entanto, a tarefa de constituir programas de treino que mantenham ou elevem os níveis de força durante a etapa competitiva é complexa (Wathen, Baechle, & Earle, 2000). Com o objetivo de ultrapassar estas limitações, o modelo de periodização por blocos propõe quatro princípios fundamentais de organização: concentração elevada de cargas de trabalho, um número mínimo de capacidades alvo num só bloco, desenvolvimento consecutivo de várias habilidades e estabelecimento de mesociclos especializados (Issurin, 2008). Ao contrário do modelo tradicional no qual várias habilidades são desenvolvidas em simultâneo, a organização por blocos pressupõe um desenvolvimento consecutivo de habilidades especificamente selecionadas, compilando um plano anual que deve ser entendido como uma sequência de estádios autónomos, onde os objetivos são obtidos através de programas de treino parcialmente renovados(Issurin, 2008). Tal como já foi referido, a tentativa de obter o máximo proveito do TF obriga a uma periodização cuidada que exige a consideração de aspetos como a relação entre volume e intensidade, ordem e sequência dos exercícios (Fleck & Kraemer, 2004). Por exemplo, se um atleta realizar um exercício para membros inferiores (e.g. agachamento) e um 46 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ exercício para membros superiores (e.g. supino), o número total de repetições será superior se a sequência for vertical e inferior quando for horizontal (Zatsiorsky & Kraemer, 2006), uma vez que solicitar de forma alternada os segmentos permite uma recuperação mais eficaz (Bompa, 1993). Apesar destas orientações, a literatura focada na periodização do TF nem sempre tem em consideração as especificidades dos vários grupos musculares, como as diferenças em número e tamanho das fibras, conteúdo de glicogénio e ATP, braços de alavanca e força de contração. Para além de aspetos neurais como a coordenação intramuscular e intermuscular, os fatores que mais influenciam a capacidade de um músculo gerar força são o número de fibras musculares e respetiva área de secção transversal (Zatsiorsky & Kraemer, 2006). Neste sentido, as diferenças de força podem ser justificadas pelo facto de músculos com maior área de secção transversal terem um maior número de pontes cruzadas (Orellana & Prada, 2000). De facto, já foi observado que para a mesma intensidade de carga, jogadores profissionais de futebol foram capazes de executar o exercício squat com cargas superiores às verificadas no exercício supino (Wisloff, Helgerud, & Hoff, 1998). Numa outra investigação, verificou-se que após a aplicação de um programa de TF de 12 semanas, os membros superiores obtiveram ganhos de 15% relativamente aos obtidos nos membros inferiores (Sousa, Mendes, Abrantes, & Sampaio, 2011). Apesar de este estudo ter sido realizado com sujeitos idosos, os resultados sugerem que a menor funcionalidade quotidiana dos membros superiores permite adaptações mais significativas quando sujeitos a um programa de TF (Enoka, 1988). As conclusões observadas nestes estudos sugerem que quando sujeitos a intensidades idênticas, os músculos dos membros inferiores são capazes de suportar cargas mais elevadas do que os membros superiores. No entanto, a literatura ainda não fundamenta de forma esclarecedora as diferenças que possam existir na adaptação aguda ao esforço entre diferentes tipos de TF, dirigidos a membros superiores, inferiores ou a ambos. Para além disso, não se conhece o modo como estas adaptações se podem refletir na performance dos jogadores, traduzida pela eficácia das várias ações motoras, técnicas e táticas. Mais, partindo do pressuposto já fundamentado que os JR devem fazer parte do processo de treino, também se desconhecem os efeitos da relação e coabitação entre diferentes tipos de TF e diferentes formatos de JR. 47 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ A intensidade do esforço em JR pode ser analisada através dos movimentos dos jogadores e/ou respostas fisiológicas/percetuais (Hill-Haas et al., 2011), cabendo ao treinador selecionar e manipular os constrangimentos que podem influenciar essa intensidade. De todas as variáveis já investigadas, interessa perceber de que forma é que a redução do número de jogadores se pode refletir nas ATT, solicitação muscular e energética. Tal como já foi referido, a utilização de JR permite a replicação de intensidades de esforço e requisitos técnico-táticos próximos dos perfis de competição (Little, 2009). A literatura também já mostrou que a redução do número de jogadores aumenta os valores da FC (ver figura 1.11), lactato sanguíneo e resposta percetual (Owen et al., 2004). Figura 1.11. Intensidade do exercício (% FCmax) em vários formatos de jogos reduzidos de futebol (Hill-Haas, Dawson, Coutts, & Rowsell, 2009). Apesar de vários estudos se terem centrado na análise das ATT em JR (Capranica et al., 2001; Duarte et al., 2009; Fanchini et al., 2011b; Jones & Drust, 2007; Kelly & Drust, 2009; Owen et al., 2004), os resultados não têm sido coerentes. Esta incerteza dificulta o esclarecimento dos técnicos no que diz respeito à relação entre a intensidade do exercício e o seu reflexo na performance técnico-tática. No entanto, sabe-se que a prática dos JR induz intensidades de esforço elevadas, requerendo aos jogadores tomadas de decisão rápidas e sobre o efeito da fadiga (Gabbett & Mulvey, 2008). 48 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Dado que fadiga atua nos sistemas nervosos central e periférico, a quebra no controlo das ações por parte dos jogadores pode estar relacionada com uma má condição física, em particular com a diminuição da força muscular (Lyons et al., 2006). Partindo do princípio de que a maioria das atividades motoras que envolvem manifestações de força e velocidade exigem um elevado estado de excitação para um ótimo desempenho (Oxendine, 1984), a influência da fadiga sobre estas capacidades pode comprometer a obtenção do rendimento pretendido (Knicker, Renshaw, Oldham, & Cairns, 2011). Assim, é indispensável que os treinadores incluam programas específicos de TF no processo de treino. Na verdade, o TF de alta intensidade contribui para melhoria da performance desportiva, melhora a eficiência mecânica, diminui os gastos energéticos (Heggelund, Fimland, Helgerud, & Hoff, 2013), aumenta o limiar anaeróbio (Marcinik, Potts, Schlabach, Will, Dawson, & Hurley, 1991), reduz a FC de repouso (Antoniazzi, Portela, & Dias, 1994) e reduz o risco de lesão (Fleck & Falkel, 1986). A otimização dos processos de treino no Andebol deve considerar a complexidade e a imprevisibilidade dos seus acontecimentos. A utilização de JR permite a replicação do perfil fisiológico e padrões técnicos e táticos, preservando a variabilidade das ações em contexto de jogo. No entanto, estas tarefas ficam aquém das solicitações musculares requeridas em certos momentos da época desportiva, obrigando os treinadores a recorrer a sessões específicas de TF. Em suma, a inclusão do TF e JR nos programas de treino parece ser decisiva para a melhoria da performance dos jogadores, no entanto não se conhecem os efeitos que a sua coabitação poderá ter no planeamento a curto prazo. A resposta a esta questão irá esclarecer de forma mais sustentada a influência de sessões específicas de TF na resposta fisiológica, técnica e tática dos jogadores em JR. Desta forma, será aportado conhecimento aos treinadores que lhes permitirá otimizar o processo de treino. 1.1.5.2. Variabilidade nos perfis de resposta de jovens futebolistas às cargas de treino O futebol de elite exige a utilização de processos de treino capazes de dar resposta à complexidade do jogo e que reproduzam fielmente os seus padrões fisiológicos, técnicos e táticos. Para que os treinadores possam prescrever cargas de treino que 49 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ repliquem as exigências competitivas, é necessário identificar os indicadores de performance que melhor definam o perfil de atividade dos jogadores em competição. O futebol pode ser descrito como uma modalidade de caráter intermitente com uma elevada variabilidade de estímulos e intensidades (Rebelo, Brito, Seabra, Oliveira, & Krustrup, 2012) resultantes da luta pela posse de bola, sprints com mudanças de direção e tomadas de decisão técnico-táticas (Gonçalves et al., 2013). Os valores de FC máxima de um jogador durante um jogo de futebol raramente estão abaixo dos 65% (Bangsbo, Mohr, & Krustrup, 2006), com valores médios e máximos de 85% e 98%, respetivamente (Krustrup, Mohr, Ellingsgaard, & Bangsbo, 2005). Na verdade, os jogadores são obrigados a executar ações de alta intensidade que incluem mudanças de direção com períodos curtos de recuperação (Dellal, Keller, Carling, Chaouachi, Wong, & Chamari, 2010). Neste sentido, a capacidade de recuperar e produzir ações subsequentes de alta intensidade é considerada um requisito importante para se atingir performances de alto nível (Girard, Mendez-Villanueva, & Bishop, 2011). São vários os parâmetros que devem ser considerados na avaliação dos perfis físicos e fisiológicos, tais como a FC (Buchheit, Simpson, Al Haddad, Bourdon, & MendezVillanueva, 2012), perceção subjetiva do esforço (Impellizzeri, Rampinini, Coutts, Sassi, & Marcora, 2004b), capacidade de executar sprints repetidos e mudanças de direção (P., Chan, & Smith, 2012). Para além destas variáveis, os perfis de tempomovimento têm sido analisados com recurso a sistemas de posicionamento global (GPS) (Casamichana & Castellano, 2010), considerados válidos para a avaliação da performance em jogos desportivos coletivos (Coutts & Duffield, 2010). O uso extensivo desta tecnologia deve-se em parte, ao facto dos aparelhos serem leves, pequenos, portáteis e permitirem analisar vários jogadores em simultâneo (Aughey & Falloon, 2010). Partindo dos registos de posicionamento, estes instrumentos são capazes de fornecer dados em tempo real relativos a velocidades de deslocamento, distâncias percorridas e acelerações, normalmente descritos em função do posto específico (Bradley, Di Mascio, Peart, Olsen, & Sheldon, 2010), nível de jogo (Mohr, Krustrup, & Bangsbo, 2003) e idades (Buchheit, Mendez-Villanueva, Simpson, & Bourdon, 2010a). Por exemplo, a distância total percorrida por jogadores jovens durante um jogo pode variar entre 4435 e 8098m, sendo que 12% inclui ações de alta intensidade (Rebelo et al., 2012), valores que tendem a aumentar com a idade (Buchheit et al., 2010a). Os defesas percorrem menores distâncias em alta intensidade do que os outros jogadores, 50 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ enquanto os médios e laterais percorrem distancias semelhantes a alta intensidade (Mohr et al., 2003). Curiosamente, a distância total percorrida durante um jogo está fortemente correlacionada com a capacidade de realizar sprints repetidos (Rampinini, Bishop, Marcora, Bravo, Sassi, & Impellizzeri, 2007). Neste sentido, a capacidade de sprints repetidos é considerada uma qualidade chave na discriminação de jogadores hábeis tecnicamente (Gabbett, 2010). Mais, as sequências de sprints repetidos e o número de sprints são afetados pela idade, posto específico e tempo de jogo, sendo que tendem a diminuir à medida que o jogo avança (Buchheit, Mendez-Villanueva, Simpson, & Bourdon, 2010b). As sessões de treino de futebol centram-se em situações jogadas com grande variabilidade ao nível dos estímulos técnicos, táticos e fisiológicos (Hill-Haas et al., 2011). Por essa razão, a manipulação de constrangimentos é uma tarefa complexa, uma vez que as características individuais de cada jogador podem permitir a manifestação de diferentes comportamentos em resposta a estímulos semelhantes (Chow, Davids, Hristovski, Araujo, & Passos, 2011). Muitas competições de equipas jovens organizam-se por escalões etários, no entanto é importante considerar que a maioria das habilidades motoras experiencia desenvolvimentos significativos durante o período pubertário (Cady, 1984; Côté & Fraser-Thomas, 2007; Fernandez-Gonzalo, De Souza-Teixeira, Bresciani, GarciaLopez, Hernandez-Murua, Jimenez-Jimenez, et al., 2010). Como consequência, os perfis físicos e fisiológicos podem variar entre jogadores de idades e tempos de prática semelhante (Cobley, Baker, Wattie, & McKenna, 2009). Ainda assim, os dados da performance no treino poderão ser usados para classificar os jogadores e estabelecer grupos homogéneos para a identificação de talentos e prescrição dos exercícios. Se os jogadores forem agrupados em função de perfis físicos e fisiológicos semelhantes, a variabilidade da resposta a nível fisiológico será minimizada, permitindo aos treinadores ter um controlo mais fiável e eficiente sobre a resposta dos jogadores. As cargas de treino semanais variam de acordo com as fases do ciclo anual, o que pode induzir diferentes stresses fisiológicos nos jogadores (Impellizzeri et al., 2004a). O período pré-competitivo é geralmente associado a maiores intensidades, principalmente devido à elevada concentração de cargas de treino (Issurin, 2008) e tempo de treino técnico-tático específico que, regra geral, consistem em JR de alta intensidade e jogos simulados (Jeong, Reilly, Morton, Bae, & Drust, 2011). Por outro lado, o calendário do 51 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ período competitivo cria constrangimentos como a recuperação após o jogo e preparação para o jogo seguinte (Gastin, Fahrner, Cook, Huntsman, Meyer, & Robinson, 2010). Assim, a principal preocupação dos treinadores durante este período é manter a capacidade física que os jogadores adquiriram durante o pré-competitivo (Reilly, 2007). Nesta linha de raciocínio, um estudo com jogadores jovens de elite mostrou que, no geral, a carga fisiológica da semana de treino foi superior no período pré-competitivo em comparação com o competitivo, verificando-se valores mais elevados de FC, mais tempo passado em zonas elevadas de FC e valores elevados de PSE (Jeong et al., 2011). Aparentemente, as cargas de treino semanais variam de acordo com a idade, observando-se um aumento da intensidade em idades mais avançadas, provavelmente pelo enfoque no desenvolvimento das capacidades físicas e preparação para a competição (Wrigley, Drust, Stratton, Scott, & Gregson, 2012). Como resultado, os microciclos são ajustados e adequados a esses objetivos. Por exemplo, a literatura já mostrou que jogadores sub-18 foram sujeitos a volumes de treino superiores refletidos por sessões adicionais de campo e ginásio quando comparados com jogadores sub-16 e sub-14 (Wrigley et al., 2012). De facto, a progressão das cargas físicas de treino é crucial para o desenvolvimento da performance física e prevenção de lesões (Matos & Winsley, 2007). Esta tendência parece reproduzir os princípios de treino defendidos pelo modelo de preparação desportiva a longo prazo, que sugere cargas de treino estruturadas de acordo com o estado de maturação do jogador (Balyi & Hamilton, 2004). http://www.youtube.com/watch?v=NEwkkjvs-C8 1.2. OBJETIVOS E HIPÓTESES A primeira parte deste estudo teve como objetivo identificar os efeitos agudos que a adição de sessões específicas de treino de força teve na resposta física, fisiológica e performance técnico-tática em sessões de treino de Andebol. Neste sentido formularamse as seguintes hipóteses: o O jogo 3x3 induz valores de FC e PSE mais elevados do que o jogo 6x6; o Os valores da FC e PSE são superiores quando existe TF máxima antecedente; 52 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ o A IV diminui após a realização do TF máxima; o A performance técnico-tática é afetada pelo TF antecedente. A segunda parte do presente trabalho focou-se na avaliação da carga externa durante unidades de treino de futebol, através da descrição de perfis de performance e métodos de classificação dos jogadores. Assim, colocaram-se as seguintes hipóteses: o O impacto fisiológico das sessões de treino tende a aumentar progressivamente com a idade. o As distâncias percorridas em treino pelos jogadores sub-19 são superiores às dos escalões sub-15 e sub-17; o Jogadores com idades idênticas apresentam perfis de performance diferentes; o Agrupar jogadores com perfis físicos e fisiológicos semelhantes reduz a variabilidade na resposta ao estímulo. 1.3. REFERÊNCIAS Abrantes, C. I., Nunes, M. I., Macas, V. M., Leite, N. M., & Sampaio, J. E. (2012) Effects of the number of players and game type constraints on heart rate, rating of perceived exertion, and technical actions of small-sided soccer games. Journal of Strength and Conditioning Research, 26(4), 976-981. doi: 10.1519/JSC.0b013e31822dd398 Achten, J., & Jeukendrup, A. E. (2003) Heart rate monitoring: applications and limitations. Sports Medicine, 33(7), 517-538. Allerheiligen, WB. (1994). Speed development and plyometric training In: Essentials of Strength Training and Conditioning (pp. 314-344). Champaign, IL: Human Kinetics. Antoniazzi, R., Portela, L., & Dias, J. (1994) Alteração do VO2 máximo de indivíduos com idades entre 50 e 70 anos, decorrente de um programa de treinamento com pesos. Revista Brasileira de Atividade Física Saúde, 4, 27-35. Araujo, D., Davids, K., & Hristovski, R. (2006) The ecological dynamics of decision making in sport. Psychology of Sport and Exercise, 7(6), 653-676. doi: 10.1016/j.psychsport.2006.07.002 53 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Araujo, D., Davids, K., & Serpa, S. (2005) An ecological approach to expertise effects in decision-making in a simulated sailing regatta. Psychology of Sport and Exercise, 6(6), 671-692. doi: 10.1016/j.psychsport.2004.12.003 Araujo, D., Travassos, B., & Vilar, L. (2010) Tactical skills are not verbal skills: a comment on Kannekens and colleagues. Percept Mot Skills, 110(3 Pt 2), 10861088. doi: 10.2466/pms.110.3c.1086-1088 Aroso, J., Rebelo, A., & Gomes Pereira, J. (2004) Physiological impact of selected game-related exercises. Journal of Sport Sciences, 22(6), 522. Astorino, T. A., Tam, P. A., Rietschel, J. C., Johnson, S. M., & Freedman, T. P. (2004) Changes in physical fitness parameters during a competitive field hockey season. J Strength Cond Res, 18(4), 850-854. doi: 10.1519/13723.1 Aughey, R. J., & Falloon, C. (2010) Real-time versus post-game GPS data in team sports. Journal of Science and Medicine in Sport, 13(3), 348-349. doi: DOI 10.1016/j.jsams.2009.01.006 Babault, N., Desbrosses, K., Fabre, M. S., Michaut, A., & Pousson, M. (2006) Neuromuscular fatigue development during maximal concentric and isometric knee extensions. Journal of Applied Physiology, 100(3), 780-785. doi: DOI 10.1152/japplphysiol.00737.2005 Badillo, J. (2000) Bases teóricas y experimentales para la aplicación del entrenamiento de fuerza al entrenamiento deportivo. Infocoes, 5(2), 3-14. Baker, D. (2007) Cycle-length variants in periodized strength/power training. Strength and Conditioning Journal, 29(4), 10-17. doi: Doi 10.1519/00126548200708000-00001 Balague, N., Torrents, C., Hristovski, R., Davids, K., & Araujo, D. (2013) Overview of complex systems in sport. Journal of Systems Science & Complexity, 26(1), 413. doi: DOI 10.1007/s11424-013-2285-0 Balsom, P. D., Gaitanos, G. C., Soderlund, K., & Ekblom, B. (1999) High-intensity exercise and muscle glycogen availability in humans. Acta Physiologica Scandinavica, 165(4), 337-345. 54 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Balyi, I., & Hamilton, A. (2004) Long-Term Athlete Development: Trainability in Childhood and adolescence. Victoria: National Coaching Institute British Columbia and Advanced Training and Performance. Bangsbo, J., Mohr, M., & Krustrup, P. (2006) Physical and metabolic demands of training and match-play in the elite football player. Journal of Sports Sciences, 24(7), 665-674. doi: 10.1080/02640410500482529 Bar-Yam, Y. (2003) Complex Systems insights to building effective teams. International Journal of Computer Science in Sport, 2(1), 8-15. Bauer, R. (1999) Gestão da Mudança: Caos e Complexidade nas Organizações. São Paulo: Editora Atlas. Bigland-Ritchie, B. (1981) EMG/force relations and fatigue of human voluntary contractions. Exerc Sport Sci Rev, 9, 75-117. Bompa, T. O. (1993) Periodization of Strength: The New Wave in Strength Training. Toronto, ON: Veritas Publishing. Boraczynski, T., & Urniaz, J. (2008) Changes in aerobic and anaerobic power indices in elite handball players following a 4-week general fitness mesocycle. Journal of Human Kinetics, 19, 131-139. Borg, G. A. V. (1982) Psychophysical Bases of Perceived Exertion. Medicine and Science in Sports and Exercise, 14(5), 377-381. doi: Doi 10.1249/00005768198205000-00012 Borg, G., Hassmen, P., & Lagerstrom, M. (1987) Perceived exertion related to heart rate and blood lactate during arm and leg exercise. Eur J Appl Physiol Occup Physiol, 56(6), 679-685. Bradley, P. S., Di Mascio, M., Peart, D., Olsen, P., & Sheldon, B. (2010) High-Intensity Activity Profiles of Elite Soccer Players at Different Performance Levels. Journal of Strength and Conditioning Research, 24(9), 2343-2351. doi: 10.1519/JSC.0b013e3181aeb1b3 Buchheit, M., Laursen, P. B., Kuhnle, J., Ruch, D., Renaud, C., & Ahmaidi, S. (2009) Game-based Training in Young Elite Handball Players. International Journal of Sports Medicine, 30(4), 251-258. doi: DOI 10.1055/s-0028-1105943 55 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Buchheit, M., Mendez-Villanueva, A., Simpson, B. M., & Bourdon, P. C. (2010a) Match Running Performance and Fitness in Youth Soccer. International Journal of Sports Medicine, 31(11), 818-825. doi: 10.1055/s-0030-1262838 Buchheit, M., Mendez-Villanueva, A., Simpson, B. M., & Bourdon, P. C. (2010b) Repeated-Sprint Sequences During Youth Soccer Matches. International Journal of Sports Medicine, 31(10), 709-716. doi: DOI 10.1055/s-00301261897 Buchheit, M., Simpson, M. B., Al Haddad, H., Bourdon, P. C., & Mendez-Villanueva, A. (2012) Monitoring changes in physical performance with heart rate measures in young soccer players. European Journal of Applied Physiology, 112(2), 711-723. doi: 10.1007/s00421-011-2014-0 Cady, L. D. (1984) Program for Increasing Health and Fitness of Firefighters. Journal of Occupational and Environmental Medicine, 26(4), 300-300. Capranica, L., Tessitore, A., Guidetti, L., & Figura, F. (2001) Heart rate and match analysis in pre-pubescent soccer players. J Sports Sci, 19(6), 379-384. doi: 10.1080/026404101300149339 Casamichana, D., & Castellano, J. (2010) Time-motion, heart rate, perceptual and motor behaviour demands in small-sides soccer games: Effects of pitch size. Journal of Sports Sciences, 28(14), 1615-1623. doi: 10.1080/02640414.2010.521168 Chen, M. J., Fan, X. T., & Moe, S. T. (2002) Criterion-related validity of the Borg ratings of perceived exertion scale in healthy individuals: a meta-analysis. Journal of Sports Sciences, 20(11), 873-899. doi: Doi 10.1080/026404102320761787 Chow, J. Y., Davids, K., Hristovski, R., Araujo, D., & Passos, P. (2011) Nonlinear pedagogy: Learning design for self-organizing neurobiological systems. New Ideas in Psychology, 29(2), 189-200. doi: 10.1016/J.Newideapsych.2010.10.001 Christou, M., Smilios, I., Sotiropoulos, K., Volaklis, K., Pilianidis, T., & Tokmakidis, S. P. (2006) Effects of resistance training on the physical capacities of adolescent soccer players. Journal of Strength and Conditioning Research, 20(4), 783-791. doi: R-17254 10.1519/R-17254.1 56 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Cobley, S., Baker, J., Wattie, N., & McKenna, J. (2009) Annual age-grouping and athlete development a meta-analytical review of relative age effects in sport. Sports Medicine, 39(3), 235-256. Collins, M. A., & Snow, T. K. (1993) Are adaptations to combined endurance and strength training affected by the sequence of training? J Sports Sci, 11(6), 485491. doi: 10.1080/02640419308730017 Côté, J., & Fraser-Thomas, J. (2007) Youth involvement in sport. In P.R.E. Crocker (Ed.), Introduction to sport psychology: A Canadian perspective. Toronto: Pearson Prentice Hall. Coutts, A. J., & Duffield, R. (2010) Validity and reliability of GPS devices for measuring movement demands of team sports. Journal of Science and Medicine in Sport, 13(1), 133-135. doi: 10.1016/j.jsams.2008.09.015 Coutts, A., Rampinini, E., Marcora, S., Castagna, C., & Impellizzeri, F. (2009) Heart rate and blood lactate correlates of perceived exertion during small-sided soccer games. Journal of Science and Medicine in Sport, 12, 79-84. Davids, K, Araújo, D, & Shuttleworth, R. . (2005). Applications of dynamical systems theory to football. In T. Reilly, J. Cabri y D. Araújo (Eds.), Science and football V (pp. 537-550). London: Routledge, Taylor & Francis. Davids, K., Button, C., Araujo, D., Renshaw, I., & Hristovski, R. (2006) Movement models from sports provide representative task constraints for studying adaptive behavior in human movement systems. Adaptive Behavior, 14(1), 7395. Dellal, A., Chamari, K., Pintus, A., Girard, O., Cotte, T., & Keller, D. (2008) Heart Rate Responses during Small-Sided Games and Short Intermittent Running Training in Elite Soccer Players: A Comparative Study. Journal of Strength and Conditioning Research, 22(5), 1449-1457. doi: 10.1519/Jsc.0b013e31817398c6 Dellal, A., Keller, D., Carling, C., Chaouachi, A., Wong, D. P., & Chamari, K. (2010) Physiologic effects of directional changes in intermittent exercise in soccer players. Journal of Strength and Conditioning Research, 24(12), 3219-3226. doi: Doi 10.1519/Jsc.0b013e3181b94a63 57 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Deschenes, M. R., Judelson, D. A., Kraemer, W. J., Meskaitis, V. J., Volek, J. S., Nindl, B. C., Harman, F. S., & Deaver, D. R. (2000) Effects of resistance training on neuromuscular junction morphology. Muscle & Nerve, 23(10), 1576-1581. doi: Doi 10.1002/1097-4598(200010)23:10<1576::Aid-Mus15>3.0.Co;2-J Duarte, R., Araújo, D., Correia, V., & Davids, K. (2012) Sports teams as superorganisms: Implications of sociobiological models of behaviour for research and practice in team sports performance analysis. Sports Medicine, 42(8), 633-642. Duarte, R., Batalha, N., Folgado, H., & Sampaio, J. (2009) Effects of exercise duration and number of players in heart rate responses and technical skills during futsal small-sided games. The Open Sports Sciences Journal, 2, 37-41. Enoka, R.M. (1988) Load and skill-related changes in segmental contributions to a weightlifting movement. Medicine and Science in Sports & Exercise, 20. Esposito, F., Impellizzeri, F. M., Margonato, V., Vanni, R., Pizzini, G., & Veicsteinas, A. (2004) Validity of heart rate as an indicator of aerobic demand during soccer activities in amateur soccer players. European Journal of Applied Physiology, 93(1-2), 167-172. doi: DOI 10.1007/s00421-004-1192-4 Fajardo, T. (1999) Nuevas Tendencias en Fuerza y Musculación: Editorial HispanoEuropea. Fanchini, M., Azzalin, A., Castagna, C., Schena, F., McCall, A., & Impellizzeri, F. M. (2011a) Effect of bout duration on exercise intensity and technical performance of small-sided games in soccer. J Strength Cond Res, 25(2), 453-458. doi: 10.1519/JSC.0b013e3181c1f8a2 Fanchini, M., Azzalin, A., Castagna, C., Schena, F., Mccall, A., & Impellizzeri, F. M. (2011b) Effect of Bout Duration on Exercise Intensity and Technical Performance of Small-Sided Games in Soccer. Journal of Strength and Conditioning Research, 25(2), 453-458. doi: Doi 10.1519/Jsc.0b013e3181c1f8a2 Faulkner, J., & Eston, R. G. (2008) Perceived exertion research in the 21(st) century: Developments, reflections and questions for the future. Journal of Exercise Science & Fitness, 6(1), 1-14. 58 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Fernandez-Gonzalo, R., De Souza-Teixeira, F., Bresciani, G., Garcia-Lopez, D., Hernandez-Murua, J. A., Jimenez-Jimenez, R., & De Paz, J. A. (2010) Comparison of technical and physiological characteristics of prepubescent soccer players of different ages. Journal of Strength and Conditioning Research, 24(7), 1790-1798. doi: 10.1519/Jsc.0b013e3181def871 Fleck, S. J., & Falkel, J. E. (1986) Value of Resistance Training for the Reduction of Sports Injuries. Sports Medicine, 3(1), 61-68. Fleck, S. J., & Kraemer, W. (2004) Designing resistance training programs (3rd ed.). Champaign, IL: Human Kinetics. Fleck, S. J., Smith, S. L., Craib, M. W., Denahan, T., Snow, R. E., & Mitchell, M. L. (1992) Upper extremity isokinetic torque and throwing velocity in team handball. Journal of Applied Sports Science Research, 6, 120-124. Foster, C., Florhaug, J. A., Franklin, J., Gottschall, L., Hrovatin, L. A., Parker, S., Doleshal, P., & Dodge, C. (2001) A new approach to monitoring exercise training. Journal of Strength and Conditioning Research, 15(1), 109-115. doi: 10.1519/00124278-200102000-00019 Frank, T. D., Michelbrink, M., Beckmann, H., & Schollhorn, W. I. (2008) A quantitative dynamical systems approach to differential learning: selforganization principle and order parameter equations. Biological Cybernetics, 98(1), 19-31. doi: DOI 10.1007/s00422-007-0193-x Gabbett, T. J. (2010) The Development of a Test of Repeated-Sprint Ability for Elite Women's Soccer Players. Journal of Strength and Conditioning Research, 24(5), 1191-1194. doi: Doi 10.1519/Jsc.0b013e3181d1568c Gabbett, T. J., & Mulvey, M. J. (2008) Time-Motion Analysis of Small-Sided Training Games and Competition in Elite Women Soccer Players. Journal of Strength and Conditioning Research, 22(2), 543-552. doi: Doi 10.1519/Jsc.0b013e3181635597 Gamble, P. (2004) Physical preparation for elite-level rugby union football. Strength and Conditioning Journal, 26(4), 10-23. Gamble, P. (2010) Strength and Conditioning for Team Sports: Sport-Specific Physical Preparation for High Performance. New York: Routledge. 59 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Gastin, P., Fahrner, B., Cook, J., Huntsman, E., Meyer, D., & Robinson, D. (2010) The effect of weekly training load on game day performance is influenced by repeat speed in elite Australian Rules football players. Journal of Science and Medicine in Sport, 12, Supplement 2(0), e125-e126. doi: http://dx.doi.org/10.1016/j.jsams.2009.10.260 Gibson, J. (1979) The ecological approach to visual perception. Boston: Houghton Mifflin. Girard, O., Mendez-Villanueva, A., & Bishop, D. (2011) Repeated-Sprint Ability - Part I Factors Contributing to Fatigue. Sports Medicine, 41(8), 673-694. Glazier, P. S. (2010) Game, set and match? Substantive issues and future directions in performance analysis. Sports Medicine, 40(8), 625-634. doi: 10.2165/11534970-000000000-00000 Gleick, J. (1987) CHAOS: Making a New Science. New York: Penguin Books. Gonçalves, B. V., Figueira, B. E., Maçãs, V., & Sampaio, J. (2013) Effect of player position on movement behaviour, physical and physiological performances during an 11-a-side football game. Journal of Sports Sciences, 1-9. doi: 10.1080/02640414.2013.816761 Gorostiaga, E. M., Granados, C., Ibanez, J., & Izquierdo, M. (2005) Differences in physical fitness and throwing velocity among elite and amateur male handball players. International Journal of Sports Medicine, 26(3), 225-232. doi: DOI 10.1055/s-2004-820974 Gorostiaga, E. M., Izquierdo, M., Iturralde, P., Ruesta, M., & Ibanez, J. (1999) Effects of heavy resistance training on maximal and explosive force production, endurance and serum hormones in adolescent handball players. European Journal of Applied Physiology and Occupational Physiology, 80(5), 485-493. doi: DOI 10.1007/s004210050622 Gorostiaga, E. M., Izquierdo, M., Ruesta, M., Iribarren, J., Gonzalez-Badillo, J. J., & Ibanez, J. (2004) Strength training effects on physical performance and serum hormones in young soccer players. Eur J Appl Physiol, 91(5-6), 698-707. doi: 10.1007/s00421-003-1032-y 60 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Grehaigne, J. F., & Godbout, P. (1995) Tactical Knowledge in Team Sports from a Constructivist and Cognitivist Perspective. Quest, 47(4), 490-505. Gruić, I., Vuleta, D., & Milanović, D. (2006) Performance indicators of teams at the 2003 men’s world handball championship in portugal. Kinesiology, 38(2), 164175. Hansen, S., Kvorning, T., Kjaer, M., & Sjøgaard, G. (2001) The effect of short-term strength training on human skeletal muscle: the importance of physiologically elevated hormone levels. Scandinavian Journal of Medicine & Science in Sports, 6, 347-354. Harris, G., Stone, M. H., O’Bryant, H., Proulx, C., & Johnson, R. (2000) Short-term performance effects of high speed, high force, or combined weight training methods. journal of Strength and Conditioning Research, 14, 14-20. Hatzimanouil, D., & Oxizoglou, N. (2004) Evaluation of the morphological characteristics and motor skills in the national junior handball teams of Greece and Yugoslavia. Journal of Human movement Studies, 46, 125-140. Heggelund, J., Fimland, M. S., Helgerud, J., & Hoff, J. (2013) Maximal strength training improves work economy, rate of force development and maximal strength more than conventional strength training. European Journal of Applied Physiology, 113(6), 1565-1573. doi: DOI 10.1007/s00421-013-2586-y Helgerud, J., Engen, L. C., Wisloff, U., & Hoff, J. (2001) Aerobic endurance training improves soccer performance. Medicine and Science in Sports and Exercise, 33(11), 1925-1931. Hickson, R. C. (1980) Interference of Strength Development by Simultaneously Training for Strength and Endurance. European Journal of Applied Physiology and Occupational Physiology, 45(2-3), 255-263. doi: Doi 10.1007/Bf00421333 Hill-Haas, S., Dawson, B., Impellizzeri, F., & Coutts, A. (2011) Physiology of SmallSided Games Training in Football A Systematic Review. Sports Medicine, 41(3), 199-220. Hill-Haas, S. V., Coutts, A. J., Dawson, B. T., & Rowsell, G. J. (2010) Time-motion characteristics and physiological responses of small-sided games in elite youth players: the influence of player number and rule changes. Journal of Strength 61 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ and Conditioning Research, 24(8), 2149-2156. doi: Doi 10.1519/Jsc.0b013e3181af5265 Hill-Haas, S. V., Dawson, B. T., Coutts, A. J., & Rowsell, G. J. (2009) Physiological responses and time-motion characteristics of various small-sided soccer games in youth players. Journal of Sports Sciences, 27(1), 1-8. doi: 10.1080/02640410802206857 Hoff, J., & Almasbalck, B. (1995) The effects of maximum strength training on throwing velocity and muscle strength in female team-handball players. Journal of Strength and Conditioning Research, 9, 255-258. Hoff, J., Wisloff, U., Engen, L. C., Kemi, O. J., & Helgerud, J. (2002) Soccer specific aerobic endurance training. British Journal of Sports Medicine, 36(3), 218-221. Holbrook, M. (2003). Adventures in Complexity: An Essay on Dynamic Open Complex Adaptive Systems, Butterfly Effects, Self-Organizing Order, Coevolution, the Ecological Perspective, Fitness Landscapes, Market Spaces, Emergent Beauty at the Edge of Chaos, and All That Jazz. 6. Hughes, M., & Franks, I. (2004) Notational Analysis of Sport (2nd ed.). London: Routledge. Impellizzeri, F. M., Marcora, S. M., Castagna, C., Reilly, T., Sassi, A., Iaia, F. M., & Rampinini, E. (2006) Physiological and performance effects of generic versus specific aerobic training in soccer players. International Journal of Sports Medicine, 27(6), 483-492. doi: 10.1055/s-2005-865839 Impellizzeri, F. M., Rampinini, E., Coutts, A. J., Sassi, A., & Marcora, S. M. (2004a) Use of RPE-based training load in soccer. Med Sci Sports Exerc, 36(6), 10421047. doi: 00005768-200406000-00018 Impellizzeri, F. M., Rampinini, E., Coutts, A. J., Sassi, A., & Marcora, S. M. (2004b) Use of RPE-based training load in soccer. Medicine and Science in Sports and Exercise, 36(6), 1042-1047. doi: 10.1249/01.Mss.0000128199.23901.2f Issurin, V. (2008) Block periodization versus traditional training theory: a review. J Sports Med Phys Fitness, 48(1), 65-75. Jeong, T. S., Reilly, T., Morton, J., Bae, S. W., & Drust, B. (2011) Quantification of the physiological loading of one week of "pre-season" and one week of "in-season" 62 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ training in professional soccer players. Journal of Sports Sciences, 29(11), 1161-1166. doi: 10.1080/02640414.2011.583671 Jones, S., & Drust, B. (2007) Physiological and technical demands of 4 v 4 and 8 v 8 games in elite youth soccer players. Kinesiology, 39(2), 150-156. Kelly, D. A., & Drust, B. (2009) The effect of pitch dimensions on heart rate responses and technical demands of small-sided soccer games in elite players. Journal of Science and Medicine in Sport, 12(4), 475-479. doi: DOI 10.1016/j.jsams.2008.01.010 Knicker, A. J., Renshaw, I., Oldham, A. R., & Cairns, S. P. (2011) Interactive processes link the multiple symptoms of fatigue in sport competition. Sports Medicine, 41(4), 307-328. doi: 10.2165/11586070-000000000-000004 Kraemer, W. J., Marchitelli, L., Gordon, S. E., Harman, E., Dziados, J. E., Mello, R., Frykman, P., Mccurry, D., & Fleck, S. J. (1990) Hormonal and Growth-Factor Responses to Heavy Resistance Exercise Protocols. Journal of Applied Physiology, 69(4), 1442-1450. Krustrup, P., Mohr, M., Ellingsgaard, H., & Bangsbo, J. (2005) Physical demands during an elite female soccer game: Importance of training status. Medicine and Science in Sports and Exercise, 37(7), 1242-1248. doi: 10.1249/01.mss.0000170062.73981.94 Krustrup, P., Mohr, M., Steensberg, A., Bencke, J., Kjaer, M., & Bangsbo, J. (2006) Muscle and blood metabolites during a soccer game: implications for sprint performance. Med Sci Sports Exerc, 38(6), 1165-1174. doi: 10.1249/01.mss.0000222845.89262.cd 00005768-200606000-00020 Lago-Penas, C., Rey, E., Lago-Ballesteros, J., Casais, L., & Dominguez, E. (2011) The Influence of a Congested Calendar on Physical Performance in Elite Soccer. Journal of Strength and Conditioning Research, 25(8), 2111-2117. doi: Doi 10.1519/Jsc.0b013e3181eccdd2 Leveritt, M., & Abernethy, P. J. (1999) Acute effects of high-intensity endurance exercise on subsequent resistance activity. Journal of Strength and Conditioning Research, 13(1), 47-51. 63 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Linnamo, V., Hakkinen, K., & Komi, P. V. (1998) Neuromuscular fatigue and recovery in maximal compared to explosive strength loading. European Journal of Applied Physiology and Occupational Physiology, 77(1-2), 176-181. Linnamo, V., Newton, R. U., Hakkinen, K., Komi, P. V., Davie, A., McGuigan, M., & Triplett-McBride, T. (2000) Neuromuscular responses to explosive and heavy resistance loading. Journal of Electromyography and Kinesiology, 10(6), 417424. doi: Doi 10.1016/S1050-6411(00)00029-8 Little, T. (2009) Optimizing the Use of Soccer Drills for Physiological Development. Strength and Conditioning Journal, 31(3), 67-74. doi: Doi 10.1519/Ssc.0b013e3181a5910d Lorenz, D. S., Reiman, M. P., & Walker, J. C. (2010) Periodization: current review and suggested implementation for athletic rehabilitation. Sports Health, 2(6), 509518. doi: 10.1177/1941738110375910 Luebbers, P. E., Potteiger, J. A., Hulver, M. W., Thyfault, J. P., Carper, M. J., & Lockwood, R. H. (2003) Effects of plyometric training and recovery on vertical jump performance and anaerobic power. Journal of Strength and Conditioning Research, 17(4), 704-709. Lyons, M., Al-Nakeeb, Y., & Nevill, A. (2006) The impact of moderate and high intensity total body fatigue on passing accuracy in expert and novice basketball players. Journal of Sports Science and Medicine, 5(2), 215-227. Magalhães, F. (1999). Relação entre indicadores de eficácia e a classificação final de equipas de andebol. Um estudo no Campeonato Nacional da 1ª Divisão Masculina. (Unpublished PhD Thesis), FCDEF - UP. Mallo, J., & Navarro, E. (2008) Physical load imposed on soccer players during smallsided training games. J Sports Med Phys Fitness, 48(2), 166-171. Marcinik, E. J., Potts, J., Schlabach, G., Will, S., Dawson, P., & Hurley, B. F. (1991) Effects of Strength Training on Lactate Threshold and Endurance Performance. Medicine and Science in Sports and Exercise, 23(6), 739-743. Marques, M. A. C., & Gonzalez-Badillo, J. J. (2006) In-season resistance training and detraining in professional team handball players. Journal of Strength and Conditioning Research, 20(3), 563-571. 64 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Matos, N., & Winsley, R. J. (2007) Trainability of young athletes and overtraining. Journal of Sports Science and Medicine, 6(3), 353-367. McBride, J. M., Triplett-McBride, T., Davie, A., & Newton, R. U. (2002) The effect of heavy- vs. light-load jump squats on the development of strength, power, and speed. Journal of Strength and Conditioning Research, 16(1), 75-82. McCaulley, G. O., McBride, J. M., Cormie, P., Hudson, M. B., Nuzzo, J. L., Quindry, J. C., & Triplett, N. T. (2009) Acute hormonal and neuromuscular responses to hypertrophy, strength and power type resistance exercise. European Journal of Applied Physiology, 105(5), 695-704. doi: DOI 10.1007/s00421-008-0951-z McGarry, T. (2009) Applied and theoretical perspectives of performance analysis in sport: Scientific issues and challenges. International Journal of Performance Analysis in Sport, 9(13), 128-140. McGarry, T., Anderson, D. I., Wallace, S. A., Hughes, M. D., & Franks, I. M. (2002) Sport competition as a dynamical self-organizing system. Journal of Sports Sciences, 20(10), 771-781. Miller, M. G., Herniman, J. J., Ricard, M. D., Cheatham, C. C., & Michael, T. J. (2006) The effects of a 6-week plyometric training program on agility. Journal of Sports Science and Medicine, 5(3), 459-465. Mohr, M., Krustrup, P., & Bangsbo, J. (2003) Match performance of high-standard soccer players with special reference to development of fatigue. Journal of Sports Sciences, 21(7), 519-528. doi: 10.1080/0264041031000071182 Moore, D. R., Burgomaster, K. A., Schofield, L. M., Gibala, M. J., Sale, D. G., & Phillips, S. M. (2004) Neuromuscular adaptations in human muscle following low intensity resistance training with vascular occlusion. European Journal of Applied Physiology, 92(4-5), 399-406. doi: DOI 10.1007/s00421-004-1072-y Morin, E. (1992) From the Concept of System to the Paradigm of Complexity. Journal of Social and Evolutionary Systems, 15(4), 371-385. doi: Doi 10.1016/10617361(92)90024-8 O'Donoghue, P. (2009) Interacting Performances Theory. International Journal of Performance Analysis in Sport, 9(1), 26-46. 65 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Ohnjec, K., Vuleta, D., Milanovic, D., & Gruic, I. (2008) Performance indicators of teams at the 2003 world handball champioonship for women in croatia. Kinesiology, 40, 69-79. Orellana, J., & Prada, R. (2000) Bases fisiológicas del entrenamiento deportivo. Sevilla: Wanceulen. Owen, A. (2003) Physiological & technical analysis of small-sided conditioned training games with professional football. Wrexham: SAGE Publications. Owen, A., Twist, C., & Ford, F. (2004) Small-sided games: The physiological and technical effect of altering pitch size and player numbers. Insight, 7, 50-53. Oxendine, J. (1984) Psychology of motor learning. Englewood Cliffs, NJ: Prentice-Hall. P., Wong D., Chan, G. S., & Smith, A. W. (2012) Repeated-sprint and change-ofdirection abilities in physically active individuals and soccer players: training and testing implications. Journal of Strength and Conditioning Research, 26(9), 2324-2330. doi: 10.1519/JSC.0b013e31823daeab Passos, P., Araujo, D., Davids, K., & Shuttleworth, R. (2008) Manipulating Constraints to Train Decision Making in Rugby Union. International Journal of Sports Science & Coaching, 3(1), 125-140. doi: 10.1260/17479540878408943 Pattersson, R., Pearson, J., & Fisher, S. (1985) Work-rest periods: their effects on normal physiologic response to isometric and dynamic work. Archives of Physical Medicine and Rehabilitation, 66, 348-352. Platonov, V. (1997) General theory of athletes’ preparation in the Olympic sports (Vol. Kiev): Olympic Literature. Porta, J., Viñaspre, P., & Morera, F. (1996) El entrenamiento de la fuerza en los deportes de equipo. Apunts: Educación física y deportes, 43, 55-62. Rampinini, E., Bishop, D., Marcora, S. M., Bravo, D. F., Sassi, R., & Impellizzeri, F. M. (2007) Validity of simple field tests as indicators of match-related physical performance in top-level professional soccer players. International Journal of Sports Medicine, 28(3), 228-235. doi: DOI 10.1055/s-2006-924340 66 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Rampinini, E., Impellizzeri, F. M., Castagna, C., Abt, G., Chamari, K., Sassi, A., & Marcora, S. M. (2007) Factors influencing physiological responses to smallsided soccer games. J Sports Sci, 25(6), 659-666. doi: 773456776 10.1080/02640410600811858 Rannou, F., Prioux, J., Zouhal, H., Gratas-Delamarche, A., & Delamarche, P. (2001) Physiological profile of handball players. Journal of Sports Medicine and Physical Fitness, 41(3), 349-353. Rebelo, A., Brito, J., Seabra, A., Oliveira, J., & Krustrup, P. (2012) Physical match performance of youth football players in relation to physical capacity. European Journal of Sport Science, 1-9. doi: 10.1080/17461391.2012.664171 Reilly, T. (2007). The training process. In The science of training - soccer: A scientific approach to developing strength, speed and endurance (pp. 1-19). London: Routledge. Reilly, T., & White, C. (2004) Small-sided games as an alternative to interval-training for soccer players. Journal of Sports Sciences, 6(22), 559. Reverdito, R., & Scaglia, A. (2007) The administration of the organizational process of the game: a proposal for the teaching of the collective games. Motriz, 3(1), 5163. Ribeiro, M., & Volossovitch, A. (2004) Andebol 1 - O ensino do Andebol dos 7 aos 10 anos: Edições FMH e Federação de Andebol de Portugal. Robertson, R. J. (2000) Perception of physical exertion: Clinical and health-fitness applications. International Journal of Psychology, 35(3-4), 91-91. Robertson, R. J. (2001) Exercise testing and prescription using RPE as a criterion variable. International Journal of Sport Psychology, 32(2), 177-188. Ronglan, L. T., Raastad, T., & Borgesen, A. (2006) Neuromuscular fatigue and recovery in elite female handball players. Scandinavian Journal of Medicine & Science in Sports, 16(4), 267-273. doi: DOI 10.1111/j.1600- 0838.2005.00474.x Roth, K. (1989) Taktik im Sportspiel (Tactics in the sport game). Schorndorf Hofmann. 67 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Sale, D. G. (1988) Neural Adaptation to Resistance Training. Medicine and Science in Sports and Exercise, 20(5), 135-145. Sale, D. G. (1992). Neural adaptations to strength training. In Strength and power in sport, ed. P.V. Komi (pp. 249-265). Oxford: Blackwell Scientific. Sampaio, J., García, G., Maçãs, V., Ibáñez, S., Abrantes, C., & Caixinha, P. (2007) Heart rate and perceptual responses to 2 x 2 and 3 x 3 small-sided youth soccer games. Journal of Sports Science and Medicine, 6(10), 121-122. Sampaio, J., Ibanez, S.J., Feu, S., Lorenzo, A., Gomez, M.A., & Ortega, E. (2008) Basketball game-related statistics that discriminate between teams' season-long success. European Journal of Sport Science, 8(6), 369-372. doi: 10.1080/17461390802261470 Sampaio, J., & Maçãs, V. (2012) Measuring tactical behaviour in football. International Journal of Sports Medicine, 33(5), 395-401. doi: 10.1055/s-0031-1301320 Sassi, R., Reilly, T., & Impellizzeri, F. (2004) A comparison of small sided games and interval training in elite professional soccer players. Journal of Sports Sciences, 22, 562. Schmidt, R., & Lee, T. (1999) Motor control and learning. A behavioral emphasis: Champaign, IL: Human Kinetics. Schöllhorn, W., Hegen, P., & Davids, K. . (2012). The Nonlinear Nature of Learning A Differential Learning Approach. The Open Sports Sciences Journal, 5, 100112. Schollhorn, W. I., Mayer-Kress, G., Newell, K. M., & Michelbrink, M. (2009) Time scales of adaptive behavior and motor learning in the presence of stochastic perturbations. Human Movement Science, 28(3), 319-333. doi: 10.1016/j.humov.2008.10.005 Shaw, R. (2003) The agent-environment interface: Simon's indirect or Gibson's direct coupling? Ecological Psychology, 15(1), 37-106. doi: Doi 10.1207/S15326969eco1501_04 Sousa, N., Mendes, R., Abrantes, C., & Sampaio, J. (2011) Differences in maximum upper and lower limb strength in older adults after a 12 week intense resistance training program. J Hum Kinet, 30, 183-188. doi: 10.2478/v10078-011-0086-x 68 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Takarada, Y., Takazawa, H., Sato, Y., Takebayashi, S., Tanaka, Y., & Ishii, N. (2000) Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans. Journal of Applied Physiology, 88, 2097-2106. Temprado, J. J., & Laurent, M. (1999) Perceptuo-motor coordination in sport: Current trends and controversies. International Journal of Sport Psychology, 30(4), 417-436. Tenenbaum, G., LevyKolker, N., Sade, S., Liebermann, D. G., & Lidor, R. (1996) Anticipation and confidence of decisions related to skilled performance. International Journal of Sport Psychology, 27(3), 293-307. Tessitore, A., Meeusen, R., Piacentini, M. F., Demarie, S., & Capranica, L. (2006) Physiological and technical aspects of "6-a-side" soccer drills. Journal of Sports Medicine and Physical Fitness, 46(1), 36-43. Verkhoshansky, Y. (2006) Special Strength Training - A Pratical Manual for Coaches. Michigan, USA: Ultimate Athlete Concepts. Vilar, L., Araújo, D., Davids, K., & Button, C. (2012) The role of ecological dynamics in analysing performance in team sports. Sports Medicine, 42(1), 1-10. doi: 10.2165/11596520-000000000-00000 Volossovitch, A. . (2008). Análise dinâmica do jogo de andebol. Estudo dos fatores que influenciam a probabilidade de marcar golo. (Unpublished PhD thesis), FMHUTL. Volossovitch, Anna, Dumangane, M., & Rosati, N. (2010) The influence of the pace of match on the dynamic of handball game. International Journal of Sport Psychology, 41, 118-118. Vuleta, D., Milanović, D., Gruić, I., & Ohnjec, K. (2005). Influence of the goals scored on final outcomes of matches of the 2003 World Handball Championships for Men in Portugal. Paper presented at the 4th International Scientific Conference on Kinesiology “Science and Profession - Challenge for the Future”, Zagreb: Faculty of Kinesiology University of Zagreb. Wagner, H., & Muller, E. (2008) The effects of differential and variable training on the quality parameters of a handball throw. Sports Biomech, 7(1), 54-71. doi: 10.1080/14763140701689822 69 Capítulo 1 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Warren, W. H. (2006) The dynamics of perception and action. Psychological Review, 113(2), 358-389. doi: Doi 10.1037/0033-295x.113.2.358 Wathen, D., Baechle, T., & Earle, R. (2000) Essentials of Strength Training and Conditioning (2nd edn). Champaign, IL: Human Kinetics. Wisloff, U., Helgerud, J., & Hoff, J. (1998) Strength and endurance of elite soccer players. Medicine and Science in Sports and Exercise, 30(3), 462-467. Wong, P. L., Chaouachi, A., Chamari, K., Dellal, A., & Wisloff, U. (2010) Effect of Preseason Concurrent Muscular Strength and High-Intensity Interval Training in Professional Soccer Players. Journal of Strength and Conditioning Research, 24(3), 653-660. doi: Doi 10.1519/Jsc.0b013e3181aa36a2 Wrigley, R., Drust, B., Stratton, G., Scott, M., & Gregson, W. (2012) Quantification of the typical weekly in-season training load in elite junior soccer players. Journal of Sports Sciences. doi: 10.1080/02640414.2012.709265 Zatsiorsky, V., & Kraemer, W. (2006) Science and Practice of Strength Training (Second ed.): Human Kinetics. Ziv, G., & Lidor, R. (2009) Physical characteristics, physiological attributes, and oncourt performances of handball players: A review. European Journal of Sport Science, 9(6), 375-386. doi: Doi 10.1080/17461390903038470 70 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ CAPÍTULO 2 71 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 2.1 ACUTE EFFECTS OF STRENGTH TRAINING IN THE PHYSIOLOGICAL AND PERCEPTUAL RESPONSE IN HANDBALL SMALLSIDED GAMES Eduardo Abade1, Catarina Abrantes1, Sergio Ibáñez2 and Jaime Sampaio1 1 University of Trás-os-Montes e Alto Douro, Research Center in Sport Sciences, Health and Human Development (CIDESD). Vila Real, Portugal. 2 Faculty of Sports Science, University of Extremadura. 2.1.1 Abstract The purpose of this study was to identify the acute effects of different strength training (ST) programs in perceptual and physiological response to handball small-sided games (SSG). Twelve senior male players participated in the study (age 22.2 ± 3.4, height 1.82 ± 0.05 m, weight 80.6 ± 5.38 kg, BMI 24.4 ± 1.33; HR max 195 ± 10.3). The heart rate (HR) and the rating of perceived exertion (RPE) were measured during SSG (3x3 and 6x6: 4 blocks of 5 minutes each) in a handball half court, with and without precedent ST. The results showed that ST increased the time spent above 90% HR max (ST x HR Zone, p < 0.01) and the RPE during handball SSG (PLAYERS x ST, p < 0.05). Additionally, the ST induced higher HR and RPE values in SSG 3x3 (PLAYERS x ST x HR Zone, p < 0.01). Thus, including ST before a SSG training unit increases the external load and induces higher HR values. Coaches may use ST to increase the workload during 6x6 games and to develop the aerobic performance during 3x3. Key words: strength training; heart rate; perceived exertion; small-sided games; handball. 72 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 2.1.2 Introduction Team sports performance is the result of a complex and dynamic process, with a high amount of uncertainty, unpredictability and randomness (Volossovitch, Dumangane, & Rosati, 2010). Therefore, the players must be able to respond to competition requests, to manage the disorder resultant from the game constraints and to adapt themselves to emergent situations of cooperation and opposition (Grehaigne & Godbout, 1998). To this end, the training units should include constraints involving decision-making, tactics or techniques that respect the appropriate functional environment (Volossovitch et al., 2010). In this sense, the small-sided games (SSG) are considered as one of the most useful drills to be used in the training process, allowing the coaches to manipulate several variables that can modify the exercise stimulus, such as the number of players or court size (Hill-Haas, Dawson, Impellizzeri, & Coutts, 2011). From a physiological standpoint, SSG can induce HR values as high as 90 to 95% of HR max (Hoff, Wisloff, Engen, Kemi, & Helgerud, 2002). In general, most studies show that reducing the number of players increase the HR, %HR max, blood lactate concentrations and perceptual response (Hill-Haas et al., 2011). Other studies have analyzed the time spent in different intensity HR zones (Gore, 2000) and concluded that reducing the number of players led to intensity increases, reflected by the time spent above 90% of HRmax (Hill-Haas, Dawson, Coutts, & Rowsell, 2009) and higher RPE values (Rampinini, Impellizzeri, Castagna, Abt, Chamari, Sassi, et al., 2007). Despite the high intensities, similar to those observed in some interval training forms (Dellal, Chamari, Pintus, Girard, Cotte, & Keller, 2008), the variability of stimulus is higher in SSG, due to the specific nature of actions inherent to these game formats (Hill-Haas et al., 2011). In fact, the high intensities and variability of stimulus allow SSG to include action patterns close to competition requests, since physiological, technical and tactical demands of the game are always present. Although these results are useful to understand the physiological demands in SSG, most of the investigations were performed in soccer. The literature is very scarce in handball and additional cautions should be taken when using the available results. Even if SSG are able to faithfully reproduce most of the patterns required to players conditioning (Impellizzeri, Marcora, Castagna, Reilly, Sassi, Iaia, et al., 2006), the replication of the muscle demands seems much more difficult. Thus, to benefit from 73 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ significant muscular adaptations, it is necessary to use intense and specific external loads, only available with specific ST (Zatsiorsky & Kraemer, 2006). In fact, the ST is essential for achieving high performances during competition (Verkhoshansky, 2006) and there are several studies showing that ST units are decisive to develop motor actions such as vertical jump (Luebbers, Potteiger, Hulver, Thyfault, Carper, & Lockwood, 2003), agility and speed (Miller, Herniman, Ricard, C., Cheatham, & Michael, 2006). Concurrent training research describes the effects of combining ST and endurancebased training, suggesting that residual fatigue occurs following the endurance component, compromising the ability of muscles to develop tension during the strength training (Hennessy & Watson, 1994). Probably for these reasons, it is common that handball high-level teams organize their weekly practices combining ST in a weights room immediately followed by technical and tactical training in court using SSGs-based training sessions. However, the available research is unclear due to differences in design factors such as mode, intensity, frequency of training and training history of subjects. For example, there is no research describing ST programs with different muscular solicitations (i.e., focused on upper limbs, lower limbs or both), neither describing their acute effects on intermittent exercise, such as simulated game situations. In fact, combining these two components may lead to conflicting physiological adaptations, endocrine changes or acute fatigue (Leveritt, Abernethy, Barry, & Logan, 1999). In regard to the acute responses to different ST programs, it seems possible that different programs might have different effects. For example, a program based on lower limbs can have an acute effect of impairing the vertical jump and agility during the game, a program based on upper limbs can have strong acute impact on passing and goal shots and a program based on both limbs can have both effects and additional energy expenditure. All these possible single and interactive effects can be indirectly addressed by the players’ physiological and perceptual responses during SSGs. In fact, it was already found deterioration on the performance of some technical skills when the exercise intensity induced RPE values above 15 (Gabbett, 2008). Because sports performance depends on the ability to performing at high-levels in physical, technique, decision making and psychological dimensions (Knicker, Renshaw, Oldham, & Cairns, 2011), it is possible that induced fatigue might affect some of these skills, reducing the performance during team sport games. Despite the important information provided, 74 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ most research was not carried in game-like situations, neglecting the fact that team sports performance is grounded in the interactions between the individual and the dynamic constraints of the environment (Araujo, Travassos, & Vilar, 2010). In essence, there is no available research describing how different ST programs can influence handball SSGs’ performance. Revealing the acute effects of ST in SSGs physiological and technical performances, can help handball coaches to optimize the training process by selecting and combining ST and SSGs according to their best interest. Therefore, the aim of the present study is to identify the acute effects of different ST in physiological and perceptual responses to handball small-sided games. 2.1.3 Methods 2.1.3.1 Subjects The sample included 12 male handball players (age 22.2 ± 3.4, height 1.82 ± 0.05 m, weight 80.6 ± 5.38 kg, BMI 24.4 ± 1.33; HR max 195 ± 10.3). All subjects were part of the same team with seven training units per week (5 handball sessions lasting for 90 minutes and two ST lasting for 60 minutes) and competed in 30 matches per season. A briefing session took time where it was presented to the players a disclosure document with all the procedures, benefits and risks associated with participation in this study. All of them were notified that they could leave the study at any time. This protocol was approved by the ethics committee of the Research Center in Sports Sciences, Health and Human Development. 2.1.3.2 Design The protocol familiarization took place in distinct stages by using ST with external loads of approximately 50% to 60% of 1 RM (Hakkinen, Pakarinen, Kraemer, Newton, & Alen, 2000) that included all ST exercises, 33 and 66 in a handball half court (400 m²). Both HR and RPE were monitored in these sessions. The following week began with the first data collection session (UPPER + SSG 33). During UPPER, the six players participating in this first part of the study were grouped in pairs to perform the sequence of a circuit with four stations. The groups organization allowed a player to rest while the other was performing the exercise, optimizing 75 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ recovery times (Zatsiorsky & Kraemer, 2006). The rotary system provided to all individuals the same recovery time between the last strength exercise and the beginning of the SSG 33. After UPPER, a 20 minutes interval was allowed to set HR monitors on each subject. After this break, the players performed the 33 SSG (4 blocks of 5 minutes each) with alternated functions between the attack and defense. At the end of the 4th block, the HR monitors were gathered and all players filled the RPE values on a printed sheet of paper to facilitate their decision (Coutts, Rampinini, Marcora, Castagna, & Impellizzeri, 2009). After a period of 72 hours from the first data collection (UPPER + SSG 33), the protocol was repeated in SSG 33 with no ST. In the three following weeks, the procedure was identical, only with a different type of ST preceding the SSG. The weeks 5, 6 and 7 followed the same organization and procedures of weeks 2, 3 and 4, however, the SSG were played in 66. The ST with 12 subjects had exactly the same methodology and organization. All SSG took place in an indoor sports court with a total area of 400m² (half court handball), however, 74.5m² belong to the goalkeeper area, which makes a playable area of approximately 325.5m². The SSG were played according to the International Handball Federation (IHF) official rules and the ball used was from size three for senior males (60cm and 475g - IHF). Several balls were placed at the playing area perimeter so that it could be immediately restored when leaving the bounding lines (Kelly & Drust, 2009). 2.1.3.3 Methodology The dependent variables were the time spent in four zones of %HR max and RPE values. The ST and handball SSG were the independent variables. The ST type was divided in four intervention levels: no strength training (NONE), strength training for upper limbs (UPPER), strength training for lower limbs (LOWER) and strength training for upper and lower limbs (TOTAL). The type of SSG had two levels: SSG 33 and SSG 66. Individual HR monitors (Polar Team System, Polar, FI) were used to record HR continuously during SSG (33 and 66) and to measure HRmax by performing the Yo- 76 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Yo Intermittent Endurance Test - Level 2 (Bangsbo, 1996). After the implementation of the protocol, HR data was downloaded to the Polar Precision Performance SW Version 4.01.029 and later exported to a spreadsheet where it was grouped in four zones of %HR max (Gore, 2000): Zone 1 (<75%), Zone 2 (≥ 75% - 84.9%), Zone 3 (≥ 85% 89.9%) and Zone 4 (≥ 90% - 100%). To determine the maximum dynamic strength the test of one maximum repetition (1RM) was performed on different days (Brown & Weir, 2001) for each strength exercise. During the protocol application, all types of ST were carried according to the hypertrophic methodology (Zatsiorsky & Kraemer, 2006) with 3 sets of 10 to 12 RM, low speed execution (4-5 seconds per repetition) and recovery periods of approximately 60 seconds. The perceived exertion was measured by using the Borg Perceived Exertion Scale (6-20) (Borg, Hassmen, & Lagerstrom, 1987). 2.1.3.4 Statistical Analysis Data are expressed as means (±S.D). The RPE and technical variables were analyzed with a 24 repeated measures ANOVA: number of players (33 or 66) and strength training situation (NONE, UPPER, LOWER, TOTAL). To analyze HR data, the zone repeated factor (with 4 levels) was included in the model, resulting in a 244 repeated measures ANOVA. Eta squared values were used as effect sizes. All analyses were performed using Statistica software version 8 (Statsoft, Tulsa USA) and the significance level was maintained at 5%. 2.1.4 Results The table 2.1 presents the results of simple effects comparisons and interactions between the number of players (33 and 66), types of ST (NONE, UPPER, LOWER and TOTAL) and time spent in the four HR zones. Also, table 2.1 shows the results of simple effects comparisons and interactions between the number of players (33 and 66) and types of ST (NONE, UPPER, LOWER and TOTAL) to the RPE values. 77 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Table 2.1. Comparing the time spent in HR zones and RPE values according to the number of players and type of ST. F p Ƞ2 Power 0.0 0.972 - - ST 4.2 0.013* 0.27 0.81 HR ZONE 7.2 0.001* 0.40 0.97 PLAYERS ST 0.1 0.980 - - PLAYERS HR ZONE 14.9 0.000* 0.58 1.00 ST HR ZONE 2.9 0.004* 0.21 0.95 PLAYERS ST HR ZONE 6.5 0.000* 0.37 1.00 78.2 0.000* 0.88 1.00 ST 9.2 0.000* 0.46 0.99 PLAYERS ST 3.3 0.032* 0.23 0.70 Simple effect/Interaction HR PLAYERS RPE PLAYERS * Significant difference between conditions (p<0.05) The ST HR ZONE interaction identified higher values of time spent in zone 4 when there was ST. The players spent more time in HR zones 1 and 2 without ST (Fig.2.1a). Figure 2.1b represents the PLAYERS ST HR ZONE interaction. In 33 SSG, ST (UPPER, LOWER and TOTAL) did not decrease the time spent at the highest intensity HR zone (Z4, ≥90 – 100%). Regardless of precedent type of ST, players spent more time in HR zones 1 and 2 during SSG 66. The PLAYERS ST interaction analysis shows that the SSG 33 induced greater RPE values than SSG 66. At both SSG, RPE values were higher when there was precedent ST (Fig. 2.1c). 78 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Figure 2.1. ST x HR ZONE interaction to the time spent in each one of the four HR zones (a); PLAYERS x ST x HR ZONE interaction to the time spent in each one of the four HR zones (b 3x3, b 6x6); PLAYERS x ST interaction to RPE values (c). 2.1.5 Discussion The purpose of this study was to identify the acute effects of different ST programs in perceptual and physiological response to handball small-sided games. In general, the results showed that ST induced higher HR and RPE values in both SSG. The results also suggest that, during SSG 33, the ST did not decrease the time spent in HR zones of highest intensity (above 85%HR max). Additionally, the responses identified in 66 SSG presented increased variability. Our results showed that after the ST, SSG 33 elicited greater HR and RPE values than those verified in SSG 66. SSG with a reduced number of players seem to induce higher physiological stimulus, probably due to the larger ratio area per player and the superior 79 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ number of ball contacts. Thus, it is possible that the addition of ST resulted in an additional muscular stimulus, reflected by the higher values of HR and RPE during SSG 33. Available research, mainly in soccer, presents several factors that may contribute to increase intensity in SSG, such as the reduction of players number (Capranica, Tessitore, Guidetti, & Figura, 2001), the greater interaction of the players with the ball and the opponents (Hill-Haas et al., 2009), the increase of individual technical and tactical actions and the higher distance travelled with the ball (Katis & Kellis, 2009). Research focused on the analysis of specific soccer motor skills during SSG (33 and 66) found that the sprint, agility and horizontal jump performances decreased after both SSG, but mainly in 33 (Katis & Kellis, 2009). The difficulty to perform some of these motor tasks can be related to the fatigue induced by SSG with a reduced number of players (Katis & Kellis, 2009). These results confirm that playing handball 33 SSG elicits a superior physiological stimulus than playing 66. Therefore, SSG 33 can be used as an important drill to improve the aerobic performance in game context. In the current results, the addition of ST did not decrease the time spent above 85% HRmax and the RPE in both SSG. Despite the SSG format, it is possible that the muscular fatigue induced by ST affected the performance of some motor skills and that might resulted in higher physiological strain during SSG. Together, the stimulus of both ST and SSG can elicit neuromuscular mechanisms that might be a handicap to perform some handball speed, agility and vertical jump based drills. Several studies have found increases in muscle fatigue immediately after ST with high loads (McCaulley, McBride, Cormie, Hudson, Nuzzo, Quindry, et al., 2009). It was also verified that ST (70% of 1RM) induced muscular fatigue and decreased muscular torque five minutes after the training (Ferri, Narici, Grassi, & Pousson, 2006), however, there were not significant changes in muscle activation and voluntary electromyography activity. This fact may suggest that peripheral mechanisms play a key role on reducing the muscular strength. The decrease in the ability to generate power is also justified by the increasing concentrations of blood lactate during the ST with high intensities (Kraemer, Marchitelli, Gordon, Harman, Dziados, Mello, et al., 1990). In this context, it has already been observed an increase in blood lactate concentration of about 10 to 13 mmol/L during a hypertrophic ST (Mero, Leikas, Knuutinen, Hulmi, & Kovanen, 2009). 80 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Handball is mainly characterized by high intensity but short duration skills, as sprints and vertical jumps (Rannou, Prioux, Zouhal, Gratas-Delamarche, & Delamarche, 2001). However, these kind of specific actions are dependent on the ability to generate power in lower limbs muscles, particularly on the knee extensors, hip extensors and plantar flexors (Frick, Schmidtbleicher, & Stutz, 1995). Muscle fatigue, high lactate concentrations and the reduction of muscle torque, seem to lead to lower agility, speed and jumping ability. Therefore, the current results suggest that ST may contribute to increase exercise intensity, which supports the higher values of RPE and the time spent above 85% HR max, as seen when ST preceded SGG. Although under different conditions, concurrent training research has also found higher HR values in aerobic interval exercise, when performed after strength training (Alves, Saavedra, Simão, Novaes, Rhea, Green, et al., 2011). Our results identified increased variability during 66 SSG, suggesting higher and less predictable inter-player differences for the same exercise. The SSGs with a higher number of players resulted in a decrease of individual contacts with the ball and, therefore, the physiological pattern becomes more intermittent, e.g., the high intensity actions are interspersed with low intensity actions with less predictable durations. Contrarily to the intermittent running exercises, the players’ activity during SSG cannot be controlled by coaches, as there are factors which influence the physiological responses and promote these heterogeneous intensities (e.g., the inclusion of goalkeepers (Dellal et al., 2008), number of contacts with the ball (Capranica et al., 2001), running without the ball (Katis & Kellis, 2009), the specific positioning and the opponents behavior (Stolen, Chamari, Castagna, & Wisloff, 2005)). In fact, the higher variability in SSGs when compared to intermittent run exercises was already identified (Dellal et al., 2008). The issue of selecting the most compatible level of ST in combination with the used SSGs is complex. One of the first physiological adaptations to exercise is the catecholamine responses, which can influence skeletal muscle force and metabolic activity (Fry, Kraemer, Vanborselen, Lynch, Triplett, Koziris, et al., 1994). Also, the mechanisms of fatigue are related to several metabolic factors (e.g. adenosine triphosphate, inorganic phosphate, phosphocreatine, lactate), diminished glucose or glycogen availability, ionic factors (e.g. K+, Na + , Ca2+, Cl - ), acidosis (Fitts, 1994), hypoxia (Amann, Romer, Pegelow, Jacques, Hess, & Dempsey, 2006), reactive oxygen 81 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ species and/or ultrastructural damage (Byrne, Twist, & Eston, 2004). In single terms and probably interactively, the symptoms underlying these mechanisms are peripheral and central fatigue, afferent feedback, diminished time to exhaustion, increased RPE, impaired motor skill outcomes and decision-making (Knicker et al., 2011). Therefore, from the current results, it might be possible to suggest that 3x3 SSG seems to promote intensities above 85% HR max regardless of the preceding ST (UPPER, LOWER, TOTAL). The 6x6 SSG, however, does not seem to induce high intensities when there was no preceding ST. In this case, the TOTAL ST was the most effective in increasing intensity. In addition, our results show that players spent more time in lower HR zones (<75% and ≥75% - 84.9%) when there was no ST. It is possible that the lower muscular stimulus may be a handicap to reach similar intensities to those verified in competition. Handball games can elicit average %HRmax values of 85% (Loftin, Anderson, Lytton, Pittman, & Warren, 1996), thus the lack of ST can compromise, mainly in 66, the replication of significant physiological demands in SSG. All ST levels (UPPER, LOWER and TOTAL) were able to promote high HR and RPE values, therefore, ST in general can be used to reach high intensities in training. Adding together, HR and RPE values show that the SSG implies high physiological loads, especially when there is precedent ST. 2.1.6 Conclusion The main findings of this study demonstrate that the ST can influence the overall intensity during SSGs. For example, the inclusion of a ST before a SSG training unit increases the external load and induces higher HR values than those verified in SSG without precedent ST. Despite of the high intensity verified at both SSG, the 33 format provided higher HR values. Thus, coaches can use ST as a useful tool to induce higher intensities during training sessions, enabling the development of aerobic performance in a game situation. When using SSG 66, coaches should consider the TOTAL program as more effective to increase the physiological stimulus. However, the possibilities of other ST methods induce different effects to those found in this study, requires further research. The data collected from this investigation may provide useful information to 82 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ coaches, helping them to organize and plan microcycles that includes co-existence of SSG and ST. 2.1.7 References Alves, J., Saavedra, A., Simão, R., Novaes, J., Rhea, M., Green, D., & Reis, V. (2011) Does aerobic and strength exercise sequence in the same session affect the oxygen uptake during and post-exercise? Journal of Strength and Conditioning Research. doi: 10.1519/JSC.0b013e318238e852 Amann, M., Romer, L. M., Pegelow, D. F., Jacques, A. J., Hess, C. J., & Dempsey, J. A. (2006) Effects of arterial oxygen content on peripheral locomotor muscle fatigue. Journal of Applied Physiology, 101(1), 119-127. doi: DOI 10.1152/jappalphysiol.01596.2005 Araujo, D., Travassos, B., & Vilar, L. (2010) Tactical skills are not verbal skills: a comment on Kannekens and colleagues. Percept Mot Skills, 110(3 Pt 2), 10861088. Bangsbo, J. (1996) Physiological factors associated with efficiency in high intensity exercise. Sports Medicine, 22(5), 299-305. Borg, G., Hassmen, P., & Lagerstrom, M. (1987) Perceived exertion related to heart rate and blood lactate during arm and leg exercise. Eur J Appl Physiol Occup Physiol, 56(6), 679-685. Brown, L.E., & Weir, J.P. (2001) ASEP procedures assessment of recomendations I: accurate muscle strength and power. Journal of Exercise Physiologyonline, 4, 1-21. Byrne, C., Twist, C., & Eston, R. (2004) Neuromuscular function after exercise-induced muscle damage - Theoretical and applied implications. Sports Medicine, 34(1), 49-69. Capranica, L., Tessitore, A., Guidetti, L., & Figura, F. (2001) Heart rate and match analysis in pre-pubescent soccer players. J Sports Sci, 19(6), 379-384. doi: 10.1080/026404101300149339 83 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Coutts, A. J., Rampinini, E., Marcora, S. M., Castagna, C., & Impellizzeri, F. M. (2009) Heart rate and blood lactate correlates of perceived exertion during small-sided soccer games. Journal of Science and Medicine in Sport, 12(1), 79-84. doi: S1440-2440(07)00193-4 10.1016/j.jsams.2007.08.005 Dellal, A., Chamari, K., Pintus, A., Girard, O., Cotte, T., & Keller, D. (2008) Heart rate responses during small-sided games and short intermittent running training in elite soccer players: a comparative study. Journal of Strength and Conditioning Research, 22(5), 1449-1457. doi: 10.1519/JSC.0b013e31817398c6 Ferri, A., Narici, M., Grassi, B., & Pousson, M. (2006) Neuromuscular recovery after a strength training session in elderly people. European Journal of Applied Physiology, 97(3), 272-279. doi: DOI 10.1007/s00421-006-0168-y Fitts, R. H. (1994) Cellular Mechanisms of Muscle Fatigue. Physiological Reviews, 74(1), 49-94. Frick, U., Schmidtbleicher, D., & Stutz, R. (1995). Muscle activation during acceleration-phase in sprint running with special reference to starting posture (abstract). Paper presented at the XV Congress of the International Society of Biomechanics., Jyvaskyla, Finland. Fry, A. C., Kraemer, W. J., Vanborselen, F., Lynch, J. M., Triplett, N. T., Koziris, L. P., & Fleck, S. J. (1994) Catecholamine Responses to Short-Term High-Intensity Resistance Exercise Overtraining. Journal of Applied Physiology, 77(2), 941946. Gabbett, T. J. (2008) Influence of fatigue on tackling technique in rugby league players. Journal of Strength and Conditioning Research, 22(2), 625-632. doi: 10.1519/JSC.0b013e3181635a6a 00124278-200803000-00041 Gore, C. (2000) Physiological tests for elite athletes. Champaign, IL: Human Kinetics. Grehaigne, J. F., & Godbout, P. (1998) Formative assessment in team sports in a tactical approach context. Journal of Physical Education, Recreation & Dance, 69, 4651. Hakkinen, K., Pakarinen, A., Kraemer, W. J., Newton, R. U., & Alen, M. (2000) Basal concentrations and acute responses of serum hormones and strength 84 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ development during heavy resistance training in middle-aged and elderly men and women. The Journal of Gerontology, 55(2), B95-105. Hennessy, L., & Watson, A. . (1994) The interference effects of training for strength and endurance simultaneously. Journal of Strength and Conditioning Resources 8, 12-19. Hill-Haas, S., Dawson, B., Impellizzeri, F., & Coutts, A. (2011) Physiology of SmallSided Games Training in Football A Systematic Review. Sports Medicine, 41(3), 199-220. Hill-Haas, S. V., Dawson, B. T., Coutts, A. J., & Rowsell, G. J. (2009) Physiological responses and time-motion characteristics of various small-sided soccer games in youth players. Journal of Sports Sciences, 27(1), 1-8. doi: Doi 10.1080/02640410802206857 Hoff, J., Wisloff, U., Engen, L. C., Kemi, O. J., & Helgerud, J. (2002) Soccer specific aerobic endurance training. British Journal of Sports Medicine, 36(3), 218-221. Impellizzeri, F. M., Marcora, S. M., Castagna, C., Reilly, T., Sassi, A., Iaia, F. M., & Rampinini, E. (2006) Physiological and performance effects of generic versus specific aerobic training in soccer players. International Journal of Sports Medicine, 27(6), 483-492. doi: DOI 10.1055/s-2005-865839 Katis, A., & Kellis, E. (2009) Effects of small-sided games on physical conditioning and performance in young soccer players. Journal of Sports Science and Medicine, 8(3), 374-380. Kelly, D. M., & Drust, B. (2009) The effect of pitch dimensions on heart rate responses and technical demands of small-sided soccer games in elite players. Journal of Science and Medicine in Sport, 12(4), 475-479. doi: S1440-2440(08)00033-9 10.1016/j.jsams.2008.01.010 Knicker, A. J., Renshaw, I., Oldham, A. R., & Cairns, S. P. (2011) Interactive processes link the multiple symptoms of fatigue in sport competition. Sports Medicine, 41(4), 307-328. Kraemer, W. J., Marchitelli, L., Gordon, S. E., Harman, E., Dziados, J. E., Mello, R., Frykman, P., Mccurry, D., & Fleck, S. J. (1990) Hormonal and Growth-Factor 85 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Responses to Heavy Resistance Exercise Protocols. Journal of Applied Physiology, 69(4), 1442-1450. Leveritt, M., Abernethy, P. J., Barry, B. K., & Logan, P. A. (1999) Concurrent strength and endurance training - A review. Sports Medicine, 28(6), 413-427. Loftin, M., Anderson, P., Lytton, L., Pittman, P., & Warren, B. (1996) Heart rate response during handball singles match-play and selected physical fitness components of experienced male handball players. Journal of Sports Medicine and Physical Fitness, 36(2), 95-99. Luebbers, P. E., Potteiger, J. A., Hulver, M. W., Thyfault, J. P., Carper, M. J., & Lockwood, R. H. (2003) Effects of plyometric training and recovery on vertical jump performance and anaerobic power. Journal of Strength and Conditioning Research, 17(4), 704-709. McCaulley, G. O., McBride, J. M., Cormie, P., Hudson, M. B., Nuzzo, J. L., Quindry, J. C., & Triplett, N. T. (2009) Acute hormonal and neuromuscular responses to hypertrophy, strength and power type resistance exercise. European Journal of Applied Physiology, 105(5), 695-704. doi: DOI 10.1007/s00421-008-0951-z Mero, A., Leikas, A., Knuutinen, J., Hulmi, J. J., & Kovanen, V. (2009) Effect of strength training session on plasma amino acid concentration following oral ingestion of leucine, BCAAs or glutamine in men. European Journal of Applied Physiology, 105(2), 215-223. doi: DOI 10.1007/s00421-008-0892-6 Miller, Michael G., Herniman, Jeremy J., Ricard, Mark D., C., Christopher, Cheatham, & Michael, Timothy J. (2006) The Effects of a 6-week Plyometric Training Program on Agility. Journal of Sports Science and Medicine, 5, 459-465. Rampinini, E., Impellizzeri, F. M., Castagna, C., Abt, G., Chamari, K., Sassi, A., & Marcora, S. M. (2007) Factors influencing physiological responses to smallsided soccer games. J Sports Sci, 25(6), 659-666. doi: 773456776 10.1080/02640410600811858 Rannou, F., Prioux, J., Zouhal, H., Gratas-Delamarche, A., & Delamarche, P. (2001) Physiological profile of handball players. Journal of Sports Medicine and Physical Fitness, 41(3), 349-353. 86 Capítulo 2 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Stolen, T., Chamari, K., Castagna, C., & Wisloff, U. (2005) Physiology of soccer - An update. Sports Medicine, 35(6), 501-536. Verkhoshansky, Y. (2006) Special Strength Training - A Pratical Manual for Coaches. Michigan, USA: Ultimate Athlete Concepts. Volossovitch, Anna, Dumangane, M., & Rosati, N. (2010) The influence of the pace of match on the dynamic of handball game. International Journal of Sport Psychology, 41, 118-118. Zatsiorsky, V., & Kraemer, W. (2006) Science and Practice of Strength Training (Second ed.): Human Kinetics. 87 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ CAPÍTULO 3 88 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 3.1. ACUTE EFFECTS OF STRENGTH TRAINING PROGRAMS ON THE VERTICAL JUMP AND TECHNICAL ACTIONS IN HANDBALL DURING PRESEASON Eduardo Abade1, Bruno Gonçalves1, José Vilaça1 and Jaime Sampaio1 1 University of Trás-os-Montes e Alto Douro, Research Center in Sport Sciences, Health and Human Development (CIDESD). Vila Real, Portugal. 3.1.1. Abstract The aim of this study was to identify the acute effects of hypertrophic strength training programs on the vertical jump and technical actions in small-sided handball games during preseason. 12 senior male players (M age = 22.2 yr., SD = 3.4) participated in 3x3 and 6x6 small-sided games preceded by no strength training or upper limbs/ lower limbs/ upper + lower limbs strength training. The results showed that strength training can affect the vertical jump performance and the effectiveness of some skills towards the end of the small-sided games duration. The higher physiological stimuli during 3x3 promote the deterioration of some skills’ proficiency, mainly during small-sided games with preceding strength training. The 6x6 elicits higher cooperation and interaction between players and potentiates the vertical jump performance after strength training. Key words: strength training; preseason; vertical jump; technical skills; small-sided games; handball. 89 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 3.1.2. Introduction Handball is characterized by repeated accelerations, sprints, jumps and repeated changes of direction that involve a great amount of body contact between players. Such demands may affect the physical performance of players during competition, elicit high fatigue and increase the risk of injury (Zebis, Bencke, Andersen, Alkjaer, Suetta, Mortensen, et al., 2011). Muscle strength and power in the pelvis, upper, and lower extremities are determinant factors in specific handball actions such as the jump throw (Wagner, Pfusterschmied, Tilp, Landlinger, von Duvillard, & Muller, 2012). Strength training is a key factor to obtain high level performance and it is essential to developing the vertical jump (Luebbers, Potteiger, Hulver, Thyfault, Carper, & Lockwood, 2003). However, adequate inclusion of strength training in the annual cycle of handball training is a complex issue, due to the diversity of contents to be trained in a concentrated competitive schedule (Verkhoshansky, 2006). Apparently, to promote maximum performance and to diminish the possibility of injury, most strength training loads should be in the first half of the preseason (Bompa, 1993). For team sports like handball, the goal of strength training should be the development of the muscle strength and strength endurance during the preseason (Issurin, 2010), immediately before the maximum strength adaptations (Bompa, 1993). Hypertrophic training is commonly used to promote structural changes in the muscle morphology and cross sectional area that support greater gains in muscle strength (Verkhoshansky, 2006). However, these structural changes are slower than neural adaptations (Sale, 1988), which may be a constraint when planning a handball preseason that usually lasts from four to six weeks. The preseason training demands for high volume and diversified exercises to develop physical and technical abilities in a short period of time (Issurin, 2010). Therefore, coaches should cautiously organize their weekly schedule to prevent for conflicting physiological responses. The performance in handball can be measured with scoring (e.g., goals) and performance indicators (e.g., successful or unsuccessful passes) (Hughes & Bartlett, 2002) during small-sided games. These situations can be manipulated to influence physiological, technical, and tactical stimuli (Hill-Haas, Dawson, Impellizzeri, & Coutts, 2011) and allow for functional movement behaviors to emerge (Pinder, Davids, & Renshaw, 2012). Small-sided games seem to increase the frequency of technical actions, specifically when performed with a small number of players (Hill-Haas, et al., 90 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 2011). Additionally, the variability of stimuli allows small-sided games to include action patterns similar to competition requests, since physiological, technical, and tactical demands of the game are strongly replicated. Therefore, small-sided games are vital to the development of skills in game-like situations and to optimize the training process during the preseason. However, small-sided games do not appear to provide significant muscle demand, i.e., specific external loads that induce considerable neuromuscular adaptation (Zatsiorsky & Kraemer, 2006). Consequently, the preseason should include both small-sided games and strength training to maximize the players’ technical and physical performance. Strength training is essential for improvement of critical handball motor actions such as the vertical jump (Marques & Gonzalez-Badillo, 2006). Vertical jump ability has been related to muscle contractile mechanisms, maximal force capacity, rate of force development, muscle coordination, and the stretch-shortening cycle (Rimmer & Sleivert, 2000). These neuromuscular patterns reproduced during the vertical jump performance can be found in handball-specific defensive (e.g., blocking) and offensive movements (e.g., jump shots). Therefore, the vertical jump is recognized as a useful index of the muscular ability to generate power and can be used to monitor performance as well as to provide important information about the functional ability of lower limbs under different conditions (Quagliarella, Sasanelli, Belgiovine, Moretti, & Moretti, 2010). Regardless of the recent investigation of the acute effects of strength training (Babault, Kouassi, & Desbrosses, 2010) and acute fatigue in response to handball match play (Thorlund, Michalsik, Madsen, & Aagaard, 2008), the available literature does not describe the effects of strength training programs with different muscular solicitations (i.e., focused on upper limbs, lower limbs or both) on players’ performance in game-like situations. Additionally, there is no research relating the acute effects of combining both strength training and small-sided games in technical and vertical jump performance during a handball preseason. Such information could provide coaches important information for planning short-term programs including both small-sided games and strength training. Therefore, the goal of the present study is to identify the acute effects of different strength training in the skill and vertical jump performance to handball small-sided games. Hypothesis 1. A significant decrease in the vertical jump performance is expected immediately after the strength training. 91 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Hypothesis 2. Greater deterioration of the vertical jump is expected after 3x3 smallsided games. Hypothesis 3. Maximum strength training is expected to impair technical performance during small-sided games. 3.1.3. Method 3.1.3.1.Participants Twelve male senior handball players who competed in the Portuguese second division volunteered to participate in this study. All participants were part of a team with an average of eight hours of training per week (M age = 22.2 yr., SD=3.4; M height =1.82 m, SD = 0.05; M weight 80.6 kg, SD = 5.38; M BMI = 24.4, SD = 1.33; M HR max = 195 bpm; SD = 10.3). The participants agreed with the protocol description and were aware of its benefits and risks. They were also notified that they could withdraw from the study at any moment without any penalty. The study protocol was conformed to the declaration of Helsinki and was approved by the ethics committee of the Research Center in Sport, Health and Human Development (Vila Real, Portugal). 3.1.3.2.Procedures The strength training type was divided in four levels: no strength training, upper limbs strength training (Upper), lower limbs strength training (Lower) and upper and lower limbs strength training (Total). The small sided games were performed in two formats: GK + 3x3 and GK + 6x6 in a handball half court. The maximum dynamic strength (1 maximum repetition, 1RM) was assessed for each exercise (Upper: Horizontal bench press, Deltoid press, Pullover, and Wrist flexion; Lower: Squat, Leg Curl, Lunge, and Plantar flexion) (Brown & Weir, 2001). The Total strength training included two exercises from both Upper and Lower (Horizontal bench press, Squat, Plantar flexion and Wrist flexion). The strength training protocol was performed according to the hypertrophic methods with 3 sets of 10 to 12 maximal repetitions at a low speed execution (5 sec. per repetition) and recovery periods of 60 sec. (Zatsiorsky & Kraemer, 2006). To measure vertical jump height, the participants performed the squat jump, counter movement 92 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ jump and abalakov jump (Bosco, Luhtanen, & Komi, 1983). The jumping height (m) was calculated with an Ergojump (Bosco System, Globus, Italy). All games were recorded with a standard camcorder and the reliability of notational analysis was inspected by calculating kappa (ĸ) coefficients. Four weeks before the protocol application, there was an anthropometric and dynamic maximum strength evaluation. In the following week, all participants were familiarized with the protocol procedures. The notational analysis of technical skills was held experimentally by the observers during the protocol familiarization. A chronological schedule of the protocol is presented in table 3.1. Table 3.1. Chronological schedule that preceded the protocol application. Week 1 Protocol presentation Presentation of protocol contents and standards. Week 2 Week 3 Week 4 Anthropometric characterization HR max evaluation Maximum dynamical strength evaluation Protocol familiarization Weight, Height and BMI assessment yo-yo Intermittent Endurance Test (Level 2) 1 RM evaluation SSG 33; SSG 66; UPPER; LOWER; TOTAL; VJ Week 5 Protocol 6 weeks Note. SSG = small sided games; Total = upper and lower limbs strength training; Upper = upper limbs strength training; Lower = lower limbs training; VJ= Vertical jump. The first data collection (3x3 + Upper) started with stretching and a low intensity run (7 km / hr.) on a treadmill for warm-up. Afterwards, the players performed two attempts for each vertical jump protocol with a 10-sec. break. The best jump value was recorded. After this first vertical jump evaluation (Pre strength training, PRE ST), a 5-min. rest interval was given before initiating Upper strength training. The strength training was done on a rotary system with four stations, to optimize the recovery time between exercises and to provide the same recovery time from the last strength training exercise to the beginning of the 3x3 small-sided game. A second vertical jump evaluation took place immediately after Upper strength training (post strength training, POS ST), followed by a 20-min. interval. After this break, a 3x3 small-sided game was performed with teams alternating attack and defense per block. Small-sided games were divided in four blocks of 5 min. (1st half, 1st and 2nd blocks; 2nd half, 3rd and 4th blocks) with 293 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ min. inter-game intervals (20 minutes of effective activity). The players were divided (following the instructions of the head coach) into two balanced teams according to their ability in passing, ball control, and game sense (Hill-Haas, et al., 2011). Immediately after the small-sided games, the vertical jump was evaluated for the third and last time (Post small-sided games, POS SSG). In that same week, after a 72-hour interval, the protocol was repeated without strength training. In the two following weeks, the protocol respected the exactly same procedure but in this case, the strength training units that preceded the 3x3 were Lower and Total strength training conditions, respectively. In Weeks 4, 5, and 6 the protocol was the same, however, strength training and 6x6 small-sided games were performed with 12 participants, so four players took part in each one of the strength training stations. The small-side games took place in an indoor court with a total area of 400 m² (325.5 m² of playable area). The games were played according to the International Handball Federation official rules and the ball used was size three for senior males (60 cm diameter, 475 g). To avoid intensity disruptions, all penalty infractions were considered as goals to the attacking team. In addition, to prevent subjectivity in rules interpretation, a single referee was selected and maintained during the whole protocol. The offensive actions were recorded within three shooting zones (Zone A: area between the midfield and 9-m line; Zone B: central zone area between the 9- and 6-m lines; Zone C: wing shooting zone). All actions were assigned to ball possessions and analyzed using the percentage per 100 ball possessions. 3.1.3.3.Measures The notational analysis of offensive technical actions included passes and catches (with and without success), set shots and jump shots (with and without success) and technical errors. The interceptions and goalkeeper actions were the considered defensive actions. Data reliability was high (ICCs above .90). 3.1.3.4.Analysis The data are presented as means and standard deviations. All data sets from technical indicators and vertical jump performance were assessed for outliers and assumptions of 94 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ normality. A repeated-measures ANOVA was performed to identify inferential differences in vertical jump performance (PRE ST, POS Stand POS SSG) according to the number of players, type of strength training, and time of testing effects. When appropriate, the Scheffe post-hoc test was used for multiple comparisons. Effect size was presented as eta squared form (mean, [95% confidence intervals]). The vertical jump performance was also presented as percentage of height variation, with the Pre strength training (PRE ST) performance being considered as the baseline. All analyses were performed using Statistica Version 8 (Statsoft, Tulsa USA) and alpha was set at .05. 3.1.4. Results The vertical jump values according to the number of players, type of strength training and time of testing are presented in Fig. 3.1. Significant differences were found in the triple interaction between the time of testing, number of players, and strength training (table 3.2). Also, differences were identified in the single effect of time of testing, in the interaction between time of testing and number of players. Overall, the vertical jump performance decreased after all types of strength training, with higher values after the 6x6 small-sided games. However, Figs. 3.1 , 3.2 and 3.3 show that after 3 small-sided games there was a decrease in vertical jump performance when the game was preceded by Upper or Lower strength training. 95 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Figure 3.1. Results from interaction Players x Strength Training x Time for squat jump values. LOWER (lower limbs strength training); POS SSG (after small sided games); POS ST (after strength training); PRE ST (before strength training); TOTAL (upper and lower limbs strength training); UPPER (upper limbs strength training). Figure 3.2. Results from interaction Players x Strength Training x Time for counter movement jump values. LOWER (lower limbs strength training); POS SSG (after small sided games); POS ST (after strength training); PRE ST (before strength training); TOTAL (upper and lower limbs strength training); UPPER (upper limbs strength training). 96 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Figure 3.3. Results from interaction Players x Strength Training x Time for abalakov jump values. Legend: LOWER (lower limbs strength training); POS SSG (after small sided games); POS ST (after strength training); PRE ST (before strength training); TOTAL (upper and lower limbs strength training); UPPER (upper limbs strength training). Table 3.2. Analysis of Variance to Assess Differences in Vertical Jump Performance by Number of Players in Small-sided Games, Type of Strength Training, and Time of Testing. Source MSE F df p 2 mean, [95% CIs] Time of testing (T) SJ 0.0125 48.8 22 <.001 0.82, [0.61, 0.88] CMJ 0.0090 34.1 22 <.001 0.76, [0.50, 0.84] AJ 0.0105 67.6 22 <.001 0.86, [0.70, 0.91] SJ 0.0016 7.5 22 <.01 0.41, [0.07, 0.59] CMJ 0.0022 8.3 22 <.01 0.43, [0.08, 0.61] AJ 0.0026 10.1 22 <.001 0.48, [0.13, 0.64] SJ 0.0016 9.1 44 <.001 0.45, [0.18, 0.57] CMJ 0.0001 3.3 44 <.05 0.23, [0.01, 0.37] AJ 0.0013 5.1 44 <.001 0.32, [0.06, 0.46] T x Players (P) T x P x Strength training 97 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ According to Fig. 3.4, the percent change in vertical jump performance from baseline, recorded after the 6x6 small-sided games (POS SSG), were lower than those after strength training (POS ST). Compared to baseline, the vertical jump performance increased after 6x6 small-sided games when there was precedent Upper and Lower strength training. However, after the 3x3 games there was a decrease from the vertical jump baseline after Upper strength training (squat jump and countermovement jump) and Lower strength training (countermovement jump and abalakov jump). Figure 3.4. Percentage (%) of the height variation from the baseline (PRE ST) to the interaction Players x Strength Training x Time. The 6x6 games promoted a higher percentage of passes than the 3x3 games (17.21±5.14 of successful and 0.59±0.22 of unsuccessful versus 9.33±2.10 of successful and 0.24±0.18 of unsuccessful, respectively). Also, the 6x6 games elicited a higher percentage of successful catches than the 3x3 (17.10±5.25 and 9.15±1.93, respectively). 98 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ The percentage of unsuccessful set shots was higher in 3x3 compared to those verified in 6x6 (0.64±0.31 and 0.33±0.19, respectively). Furthermore, significant differences were identified in the percentage of technical errors between 3x3 and 6x6 games when there was Total strength training (0.12±0.08 and 0.01±0.01, respectively). The percentage of interceptions was higher in the 6x6 (0.41±0.21) compared to those occurred in the 3x3 (0.10±0.09). The percentage of goalkeeper actions increased in the second half of both SSG (first half, 0.95±0.33; second half, 1.34±0.51) and it was higher when there was precedent Upper (1.45±0.67) and Lower strength training (1.21±0.43). Finally, the number of players influenced the number of shots per shooting zone, with a higher number of shots in the wingers’ position (zone C) being recorded in 3x3 small-sided games (28.08±12.28 and 12.84±3.77). Table 3.3. Analysis of Variance to Assess Statistical Differences in % of Technical Actions by Number of Players in Small-sided Games, Type of Strength Training and Half (only statistical significant differences are presented). Source MSE F df p 2 mean, [95% CIs] Number of players Passes (successful) 16.775 28.5 16 <.001 0.64, [0.27, 0.78] Passes (unsuccessful) 0.0421 24.7 16 <.001 0.61, [0.23, 0.76] Catches (successful) 17.230 27.3 16 <.001 0.63, [0.26, 0.77] Set shots (unsuccessful) 0.0605 16.3 16 <.001 0.51, [0.12, 0,69] Interceptions 0.0347 22.4 16 <.001 0.58, [0.20, 0.74] 0.0831 11.9 16 <.01 0.69, [0.28, 0.79] 0.0006 3.65 16 <.05 0.41, [0.00, 0.59] 0.0285 4.1 16 <.05 0.43, [0.00, 0.61] Half Goalkeeper actions Number of players x Strength training Technical errors Strength training Half Goalkeeper actions 3.1.5. Discussion The results showed that vertical jump decreased after all types of strength training, probably justified by the neuromuscular process, elastic and contractile capacity of the 99 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ muscle structure (Komi, Nicol, & Marconnet, 1992) and to the present study hypertrophic strength training methodology. In fact, this strength training methodology can increase blood lactate concentrations up to 10 to 13 mmol (Mero, Leikas, Knuutinen, Hulmi, & Kovanen, 2009), impair the muscular contraction and the acute capacity of the stretch shortening cycle to generate muscular torque (Rodacki, Fowler, & Bennett, 2002). These symptoms play a crucial role on the reducing of the lower limbs strength power, which may support the deterioration of the vertical jump performance after strength training units. The results showed that vertical jump absolute values increased after 6x6 games when compared to the POS ST values. Previous studies have demonstrated that high-threshold fast motor units are recruited during maximal intensity actions such as vertical jump (Kubo, Morimoto, Komuro, Tsunoda, Kanehisa, & Fukunaga, 2007). In fact, vertical jump height is considered an important indicator of the lower limbs muscle power and it has been used to assess the lower extremity function and to measure the power development because of its high reproducibility (Slinde, Suber, Suber, Edwen, & Svantesson, 2008). Also, strength training research has shown that performing maximal (or near maximal) muscular contractions can produce short-term increases in maximal force due to phosphorylation of myosin light chains resulting from the initial muscle activity and excitability of alfa-motoneurons resulting in a greater contractile performance after previous muscular activity (Sweeney, Bowman, & Stull, 1993). Thus, it seems that maximal voluntary contractions can improve the acute muscle peak torque and the explosive muscle performance. In contrast, vertical jump capacity was impaired after 3x3 with precedent Upper strength training (squat and counter movement jumps) and Lower strength training (countermovement and abalakov jumps). One of the possible reasons is that small-sided games with a higher number of players have lower physiological impact because the addition of players lowers %HRmax, blood lactate concentrations and perceived exertion (Hill-Haas, et al., 2011). The strength training using high loads promotes acute muscular fatigue, however, it was already found that after a 60-min. hypertrophy strength training, lactate concentrations and the ability to generate force returned to levels close to those recorded before the strength training (McCaulley, McBride, Cormie, Hudson, Nuzzo, Quindry, et al., 2009). The time gap between the strength training and game situations, the apparently recovery of the ability to generate power and the stimulus elicited by 6x6, may have resulted in the 100 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ potentiating of the vertical jump performance. Indeed, the agility, sprint and jump capacity decline after playing a soccer 3x3 game (Hill-Haas, et al., 2011). Considering that sprint capacity depends on the stretch-shortening cycle muscle function of upper and lower musculature and its relation with vertical jump height (Maulder & Cronin, 2005), the general impairment of the vertical jump performance after 3x3 with preceding strength training may be explained by the decrease of both limbs muscle power. Interestingly, despite of the importance acknowledged to lower limbs when performing jumping actions, upper extremity strength is also important in jump throws, due to difficulties to use trunk rotation or lower extremity force (Fleck, Smith, Craib, Denahan, Snow, & Mitchell, 1992). Apparently, the high intensity promoted by 3x3 resulted in vertical jump decreases and did not allow recovering from fatigue induced by Upper and Lower strength training. The 6x6 small-sided games promoted more successful and unsuccessful passes, successful catches and interceptions, suggesting higher interaction between the players for the same playable area. The higher number of passing possibilities in 6x6 has facilitated the occurrence of successful catches and passes. On the other hand, it appears that the reduction of the ratio area per player and the consequent proximity between players has provided a higher number of unsuccessful passes and interceptions. Opposing to the small-sided games with a reduced number of players that seem to decrease the available choices for the player with ball, the 6x6 games appear to facilitate the cooperation between players. Previous research has found that the addition of players increased the number of skills per team, while reducing the number of players has been related to the increase of individual contacts with the ball (Hill-Haas, et al., 2011). The small-sided games with smaller number of players reduced the solutions to the player with the ball and consequently, the possibilities of cooperation. As a consequence, the tendency of the player to solve the constraints using individual solutions increases. Adding together, it is possible that the higher physiological stimulus and the increase of individual actions promoted by 3x3 games may not allow sustaining the technical skill proficiency. In fact, the present study showed that the number of unsuccessful set shots was higher in 3x3, which supports the idea that high intensity game situations may be counterproductive in terms of playing performance. The number of shots in the wingers’ zone (zone C) was higher during 3x3, suggesting that players tend to search for unoccupied areas in the lateral corridors when the number 101 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ of players is lower. In fact, it was already showed that small-sided games with a smaller number of players require different tactical requirement (Hill-Haas, et al., 2011). The greater distances travelled when the ratio area per player is higher, turn out the game pattern to be more unpredictable. In accordance to previous research (Hill-Haas, et al., 2011), it may be suggested that the relationship between the individual workout profiles and the skills performance should be the target of future investigations to help clarifying these results. The 3x3 with precedent Total strength training induced a higher number of technical errors. The high intensity exercises like strength training and small-sided games with a smaller number of players can increase the peripheral and central fatigue, impair the motor skills outcomes and decision-making (Knicker, Renshaw, Oldham, & Cairns, 2011). Adding together, these fatigue related symptoms seem to affect the skill performance as it is shown by the increase of technical errors verified in current study when the 3x3 small-sided games was preceded by Total strength training. Additionally, the acute muscular fatigue elicited by the Lower and Upper strength training may have affected the lower and upper limbs capacity to generate power during both SSG, which supports the higher occurrences of unsuccessful jump shots. Apparently, high-duration small-sided games decrease the number of consecutive contacts with the ball, suggesting that as game progresses, players tend to solve the constraints using less individual solutions. In the final 15 minutes of a soccer game, the peak sprinting speed can be hampered (Bangsbo & Mohr, 2005) and replacement players can perform 25% more high-intensity running and 63% more sprinting (Mohr, Krustrup, & Bangsbo, 2003). These fatigue manifestations can deteriorate the technique execution and the throwing velocity (Knicker, et al., 2011), which explains the increased number of goalkeeper actions in the final moments of the small-sided games with preceding strength training (mostly after Upper and Lower). Short-term planning in team sports requires that coaches understand the acute effects of combining strength and technical-tactical training. This study provided new evidences on how strength training may be combined with court training (small-sided games). The vertical jump capacity is impaired after maximum strength training. Comparatively to the moment immediately following strength training, the vertical jump height increases after 6x6, but is impaired after 3x3 with precedent Upper and Lower strength training. The high intensity promoted by 3x3 does not allow recovering from fatigue induced by 102 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Upper and Lower strength training, probably due to the decrease of both limbs muscle power. The higher physiological stimuli during 3x3 promote the deterioration of some technical skills proficiency, mainly during high duration small-sided games with preceding strength training. The 6x6 elicits a higher cooperation and interaction between players and potentiates the vertical jump performance after strength training. Coaches usually consider the preseason as a specific period to develop technical-tactical skills but also to increase the players’ muscle mass. These findings highlight the importance of selecting adequate court training exercises after a hypertrophic strength training session. 103 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 3.1.6. References Babault, N., Kouassi, B. Y. L., & Desbrosses, K. (2010) Acute effects of 15 min. static or contract-relax stretching modalities on plantar flexors neuromuscular properties. Journal of Science and Medicine in Sport, 13(2), 247-252. DOI: 10.1016/j.jsams.2008.12.633 Bangsbo, J., & Mohr, M. (2005) Variation in running speed and recovery time after a sprint during top-class soccer matches. Medicine and Science in Sports and Exercise, 37, S87. Bompa, T. O. (1993) Periodization of strength: the new wave in strength training. Toronto, ON: Veritas Publishing. Bosco, C., Luhtanen, P., & Komi, P. V. (1983) A Simple Method for Measurement of Mechanical Power in Jumping. European Journal of Applied Physiology and Occupational Physiology, 50(2), 273-282. Brown, L.E. and Weir J.P. (2001) ASEP Procedures recommendation I: Accurate assessment of muscular strength and power, Journal of Exercise Physiology 4, 1-21. Fleck, S. J., Smith, S. L., Craib, M. W., Denahan, T., Snow, R. E., & Mitchell, M. L. (1992) Upper extremity isokinetic torque and throwing velocity in team handball. Journal of Applied Sports Science Research, 6, 120-124. Hill-Haas, S., Dawson, B., Impellizzeri, F., & Coutts, A. (2011) Physiology of smallsided games training in football: a systematic review. Sports Medicine, 41(3), 199-220. Hughes, M. D., & Bartlett, R. M. (2002) The use of performance indicators in performance analysis. Journal of Sports Sciences, 20(10), 739-754. Issurin, V. (2010) New horizons for the methodology and physiology of training periodization block periodization: new horizon or a false dawn? Reply. Sports Medicine, 40(9), 805-807. Knicker, A. J., Renshaw, I., Oldham, A. R., & Cairns, S. P. (2011) Interactive processes link the multiple symptoms of fatigue in sport competition. Sports Medicine, 41(4), 307-328. DOI: 10.2165/11586070-000000000-000004 104 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Komi, P. V., Nicol, C., & Marconnet, P. (1992) Neuromuscular Fatigue during Repeated Stretch-Shortening Cycle Exercises. Muscle Fatigue Mechanisms in Exercise and Training, 34, 172-181. Kubo, K., Morimoto, M., Komuro, T., Tsunoda, N., Kanehisa, H., & Fukunaga, T. (2007) Influences of tendon stiffness, joint stiffness, and electromyographic activity on jump performances using single joint. European Journal of Applied Physiology, 99(3), 235-243. DOI: 10.1007/s00421-006-0338-y Luebbers, P. E., Potteiger, J. A., Hulver, M. W., Thyfault, J. P., Carper, M. J., & Lockwood, R. H. (2003) Effects of plyometric training and recovery on vertical jump performance and anaerobic power. Journal of Strength and Conditioning Research, 17(4), 704-709. Marques, M. A. C., & Gonzalez-Badillo, J. J. (2006) In-season resistance training and detraining in professional team handball players. Journal of Strength and Conditioning Research, 20(3), 563-571. Maulder, P., & Cronin, J. (2005) Horizontal and vertical jump assessment: reliability, symmetry, discriminative and predictive ability. Physical Therapy in Sport, 6(2), 74-82. DOI: 10.1016/j.ptsp.2005.01.001 McCaulley, G. O., McBride, J. M., Cormie, P., Hudson, M. B., Nuzzo, J. L., Quindry, J. C., & Triplett, N. T. (2009) Acute hormonal and neuromuscular responses to hypertrophy, strength and power type resistance exercise. European Journal of Applied Physiology, 105(5), 695-704. DOI: 10.1007/s00421-008-0951-z Mero, A., Leikas, A., Knuutinen, J., Hulmi, J. J., & Kovanen, V. (2009) Effect of strength training session on plasma amino acid concentration following oral ingestion of leucine, BCAAs or glutamine in men. European Journal of Applied Physiology, 105(2), 215-223. DOI: 10.1007/s00421-008-0892-6 Mohr, M., Krustrup, P., & Bangsbo, J. (2003) Match performance of high-standard soccer players with special reference to development of fatigue. Journal of Sports Sciences, 21(7), 519-528. DOI: 10.1080/0264041031000071182 Pinder, R. A., Davids, K., & Renshaw, I. (2012) Metastability and emergent performance of dynamic interceptive actions. Journal of Science and Medicine in Sport. DOI: 10.1016/j.jsams.2012.01.002 105 Capítulo 3 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Quagliarella, L., Sasanelli, N., Belgiovine, G., Moretti, L., & Moretti, B. (2010) Evaluation of standing vertical jump by ankle acceleration measurement. Journal of Strength and Conditioning Research, 24(5), 1229-1236. Rimmer, E., & Sleivert, G. (2000) Effects of a plyometrics intervention program on sprint performance. Journal of Strength and Conditioning Research, 14(3), 295-301. Rodacki, A. L. F., Fowler, N. E., & Bennett, S. J. (2002) Vertical jump coordination: fatigue effects. Medicine and Science in Sports and Exercise, 34(1), 105-116. Sale, D. G. (1988) Neural adaptation to resistance training. Medicine and Science in Sports and Exercise, 20(5), 135-145. Slinde, F., Suber, C., Suber, L., Edwen, C. E., & Svantesson, U. (2008) Test-retest reliability of three different countermovement jumping tests. Journal of Strength and Conditioning Research, 22(2), 640-644. DOI: 10.1519/Jsc.0b013e3181660475 Sweeney, H. L., Bowman, B. F., & Stull, J. T. (1993) Myosin light-chain phosphorylation in vertebrate striated muscle – regulation and function. American Journal of Physiology, 264(5), C1085-C1095. Thorlund, J. B., Michalsik, L. B., Madsen, K., & Aagaard, P. (2008) Acute fatigueinduced changes in muscle mechanical properties and neuromuscular activity in elite handball players following a handball match. Scandinavian Journal of Medicine & Science in Sports, 18(4), 462-472. DOI: 10.1111/j.1600-0838.2007.00710.x Verkhoshansky, Y. (2006) Special strength training - a pratical manual for coaches. Detroit, MI: Ultimate Athlete Concepts. Wagner, H., Pfusterschmied, J., Tilp, M., Landlinger, J., von Duvillard, S. P., & Müller, E. (2012) Upper-body kinematics in team-handball throw, tennis serve, and volleyball spike. Scandinavian Journal of Medicine & Science in Sports, n/a-n/a. Zatsiorsky, V., & Kraemer, W. (2006) Science and practice of strength training (2nd ed.): Human Kinetics. Zebis, M. K., Bencke, J., Andersen, L. L., Alkjaer, T., Suetta, C., Mortensen, P., Kjaer, M., & Aagaard, P. (2011) Acute fatigue impairs neuromuscular activity of anterior cruciate ligament-agonist muscles in female team handball players. Scandinavian Journal of Medicine & Science in Sports, 21(6), 833-840. DOI: 10.1111/j.16000838.2010.01052.x 106 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ CAPÍTULO 4 107 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 4.1. TIME-MOTION AND PHYSIOLOGICAL PROFILE OF FOOTBALL TRAINING SESSIONS PERFORMED BY UNDER 15, UNDER 17 AND UNDER 19 ELITE PORTUGUESE PLAYERS Eduardo Abade1, Bruno Gonçalves1, Nuno Leite1 and Jaime Sampaio1 1 University of Trás-os-Montes e Alto Douro, Research Center in Sport Sciences, Health and Human Development (CIDESD). Vila Real, Portugal. 4.1.1. Abstract The aim of this study was to provide time-motion and physiological profiles of football training sessions (TS) performed by under 15, under 17 and under 19 elite level Portuguese players. 151 elite players of under 15 (age 14.0±0.2 n=56), under 17 (age 15.8±0.4 n=66) and under 19 (age 17.8±0.6 n=29) participated in the study during a 9week period. Time-motion and body impact data were collected using GPS technology (15Hz) with heart rate monitored continuously (1Hz) across 38 randomly selected TS that resulted in a total of 612 samples. The total distances covered (m) were higher in U17 (4648.3±831.9), followed by U19 (4212.5±935.4) and U15 (3964.5±725.4) players (F=45.84, p<.001). Total body impacts and relative impacts were lower in U15 (total: 490.8±309.5, F=7.3, p<.01), but no differences were identified between U17 (total: 584.0±363.5) and U19 (total: 613.1±329.4). U19 players had less high/very high intensity activity (F=11.8, p<.001) and moderate intensity activity (F=15.07, p<.001). The heart rate values showed significant effects of zones (F=575.7, p<.001) and interaction with age groups (F=9.7, p<.001) with pairwise differences between all zones. All players spent most of time below 75% HRmax. Results showed high variability between training sessions, refraining from identifying meaningful trends when measuring performance, although, different demands were identified according to the age groups. The U15 TS were less physiologically demanding, probably caused by increased focus on small-sided games to develop basic tactical principles and technical skills. The focus on game like-situations imposed a higher external and internal workload on U17 and U19 players. Key words: age groups; workloads; youth football 108 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 4.1.2. Introduction The identification of key performance indicators in football is important to improve the training process among youths. Football is an intermittent team sport that includes both high and low intensities with mean and peak heart rates between 69% and 91% of maximal values, respectively1. Also, short-term training field periods can elicit average HR values (b.min-1) of 135±5, 151±4 and 151±5 in U18, U16 and U14 age groups2. The variability and unpredictability of the game is reflected in accelerations, decelerations, changes of direction and in the execution of several technical skills, all of them having a strong effect in energy expenditure3. For these reasons, the training drills should include different physiological stimuli to provide optimal adaptations4. If the training process is exclusively directed to the development of technical and tactical skills, the intensity and the variability of the physiological stimulus could be compromised. Thus, in order to promote an effective transfer to the competitive environment, it is suggested that the sport-specific training must provide the inclusion of technical and tactical abilities in similar conditions to those which occurs during the match play5. In essence, the stimulus intensity is a key variable that influences the training response and should be carefully considered when short and mid-term plans are designed. Describing the intensity of training can provide valuable information for adjusting the training stimulus to the players’ specific needs6. The study of important variables such as the number of sprints performed, high-intensity running and total distance covered7, can contribute for a better understanding of the performance during a game or training session. The total distance covered by youth players during a match is approximately 6311 meters (ranging from 4435 to 8098m) with 12% comprising high intensity activities1. The analysis of these movement patterns can be useful to study the activity profiles of players8, however, football is a contact sport that requires the performance of other specific actions such as tackles and jumps9. From this point of view, literature is scarce describing the body impacts experienced by football players, either in training or game situation. An accurate determination of the G forces experienced by football players might help to better understand the competition physical demands10. Moreover, adding physiological variables such as the heart rate to these work-rate profiles can be helpful in understanding the oscillations in players’ performance during training drills. Heart rate monitoring has been regularly used to assess the intensity during training and 109 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ game situations and it has been recognized as a valid indicator to quantify physical demands9. The available research in football time-motion and physiological responses is mostly focused in competition demands and disregards the training sessions (TS). In fact, there seems to be a clear need to have reference values regarding the physical demands according to different age groups in TS. The availability of such data can help coaches to support daily planning by selecting task constraints that may optimize the players’ performance development. Therefore, the aim of this study was to describe the timemotion and physiological profile of TS performed by under 15, under 17 and under 19 elite level Portuguese players. 4.1.3. Methods 4.1.3.1.Subjects The sample included 151 elite young Portuguese football players of under 15 (three U15 teams, n=56), under 17 (four U17 teams, n=66) and under 19 (two U19 teams, n=29) age groups (see table 4.1). The players belong to five different elite youth teams that were competing in the national championship (2011/2012 season). The participants, their parents and coaches agreed with the protocol description and were notified that they could withdraw from the study at any moment. This protocol was conformed to the declaration of Helsinki and was approved by the ethics committee of the Research Center in Sports Sciences, Health and Human Development (Vila Real, Portugal). The sample size was calculated with G*Power (Version 3.1.5.1 Institut für Experimentelle Psychologie, Düsseldorf, Germany) for an effect size of 0.4, an α of 0.05, and a power of 0.8 (1-β). The total sample size computed by this method was 66, i.e., a minimum of 22 subjects in each group. Table 4.1. Description of players’ sub-samples. U15 (n=56) U17 (n=66) U19 (n=29) F p Age (years) 14.0±0.2 15.8±0.4 17.8±0.6 4137.9 <.001 Height (m) 1.71±0.07 1.76±0.06 1.77±0.07 46.5 <.001 Weight (kg) 60.1±6.3 65.8±5.5 70.0±5.6 170.1 <.001 BMI (a.u) 20.4±1.2 21.2±1.4 22.4±1.0 154.5 <.001 Experience (years) 5.4±1.2 6.8±1.7 9.0±1.7 312.5 <.001 Significant differences are identified as: (a) U15 vs. U17; (b) U15 vs. U19; (c) U17 vs. U19. 110 Post-hoc a,b,c a,b a,b,c a,b,c a,b,c Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 4.1.3.2.Design The study was conducted during the competitive season over a 9-week period (December to February) and 38 randomly chosen TS (U15 n=12, U17 n=16 and U19 n=10) representing a total of 612 cases. All the practice sessions were performed at the same time period of the day (from 16.30h to 21.00h) on natural turf pitches, under similar environmental conditions (temperature 14–19°C, relative humidity 52–66%). Both U15 and U17 teams trained in the same 60x40 meters on an outdoor pitch (4 TS per week with an average duration of 90 minutes), while U19 teams trained in an outdoor pitch with official dimensions (5 TS per week with an average duration of 90 minutes). For each age group, all TS were continuously performed in the same pitch. Besides the regular physical education classes, none of the players was involved in some other sport activity. The average number of players per training unit was 23±4. 4.1.3.3.Methodology All practice sessions started with low intensity running and ball possession drills for warm up and ended with a standardized cool down consisting of stretching exercises. Players were allowed to consume water during a specific training session recovery period (approximately 3 minutes). The goals of the TS differed among the age groups. The clubs and coaches authorized to perform only a comprehensive general description of practice sessions’ used drills. TS were mainly based on constrained small-sided games according to each age group technical, tactical and physical aims. The U15 TS mainly included the development of technical skills and elementary tactical principles. Although the specific goals of U17 practices remained similar to U15, there was an increased focus in game-like situations. The U19 TS included constrained small-sided games focused on team tactical principles and physical conditioning stimulus. Players were allowed to consume water during a specific TS recovery period (approximately 3 minutes). The time motion variables were collected with 20 GPS units working at a sampling frequency of 15Hz (SPI-Pro X II, GPSports, Canberra, Australia). Although the validity and reliability of 10 Hz devices were already inspected by independent verifications 11, no validation study has been done for 15Hz units. The variables recorded were the relative distance covered per minute (m.min-1), the total distance covered (m) and the 111 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ distances at different speed zones12: zone 1 (0-6.9 Km.h-1), zone 2 (7.0-9.9 Km.h-1), zone 3 (10.0-12.9 Km.h-1), zone 4 (13-15.9 Km.h-1), zone 5 (16-17.9 Km.h-1) and zone 6 (≥18.0 Km.h-1). Sprints (zone 6) were also measured by number, average time interval and average distance covered. Additionally, three ratios were calculated in order to relate distance covered at high/very high (above 16 Km.h-1), moderate (10.0-15.9 Km.h1 ) and low-intensity (7.0-9.9 Km.h-1) with distance covered at very low intensities (0-6.9 km.h-1) normalized for each 100 meters for comparison purposes. These work:rest related ratios are frequently used in the literature to describe the activity profiles13,14. The heart rate (HR) data were recorded continuously with individual monitors (Polar Team System, Polar, FI) and grouped into four zones of %HRmax15: zone 1 (<75%), zone 2 (75% - 84.9%), zone 3 (85% - 89.9%) and zone 4 (≥ 90%). To measure the players’ HRmax, the Yo-Yo intermittent recovery level 2 test was performed16,17. Also, the GPS devices are coupled with a 100 Hz tri-axial accelerometer which allowed the estimation of body impacts18. This variable was grouped into six zones of G force10: Zone 1 (< 5.0–6.0g), Zone 2 (6.1-6.5g), Zone 3 (6.5-7.0g), Zone 4 (7.1-8.0g), Zone 5 (8.1-10.0g) and Zone 6 (> 10.1g). Also, the relative impacts per minute and the total impacts performed (independently of the zones) were recorded. The GPS and the HR devices were attached to the players and activated 15 minutes before the beginning of each training session, according to the manufacturer guidelines. The analysed TS had different durations, therefore, all the data was normalized to 60 minutes of training time. 4.1.3.4.Statistical Analysis The data are presented as means ± standard deviations. The mean intersection coefficient of variation (%) was obtained across all considered variables according to the age groups. A one-way ANOVA was performed to identify the differences in total and relative distance covered, body impacts and workout ratios across the age groups. The sprint activity variables were tested using non-parametric Mann-Whitney U tests. Three repeated measures factorial ANOVA models were performed to identify differences in time motion (6 zones x 3 age groups), heart rate (4 zones x 3 age groups) and body impact zones (6 zones x 3 age groups) according to the age groups. Pairwise differences and post-hoc comparisons were tested with Bonferroni post-hoc test. Finally, a non-parametric independent sample Kruskal-Wallis test was performed to 112 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ identify the differences in coefficient of variation (%) according to the age groups19. All data sets were tested for each statistical technique corresponding assumptions. These calculations were done SPSS Software (version 18.0, Chicago, Illinois, USA). The statistical significance was maintained at 5%. 4.1.4. Results The table 4.2 presents the results from distance covered, sprint characterization and impacts across age groups. The total and relative distances covered presented significant differences between age groups (F=40.2, p<.001). The number of sprints (activity performed above 18 Km.h-1) were different between U15 and U17 (10.9±6.3 and 16.4±8.2, z=-7.2 p<.001, respectively) and between U17 and U19 (16.4±8.2 and 11.8±7.9, z=-5.1 p<.001, respectively). The average time interval presented differences between U19 and both U15 (z=-2.2, p<.05) and U17 (z=-2.6, p<.01). Also, the average distance covered for each sprint was significant higher (z=-2.6, p<.01) in U17 than in U19 (13.0±5.3 and 11.8±6.7, respectively). In addition, the total impacts and relative impacts presented statistical differences (F=7.3, p<.01) between U15 and the other two age groups. No differences were found between U17 and U19. Table 4.2. Analysis of distance covered, sprint characterization and body impacts across age groups. Variables U15 U17 U19 Distance covered (m) Total 3964.5±725.4 4648.3±831.9 4212.5±935.4 -1 Relative (m.min ) 66.1±12.1 77.5±13.9 70.2±15.6 Sprint Number 10.9±6.3 16.4±8.2 11.8±7.9 Time interval per sprint (s) 2.1±0.8 2.3±0.9 2.1±1.2 Average distance covered per sprint (m) 12.1±4.9 13.0±5.3 11.8±6.7 Body Impacts (number) Total 490.8±309.5 584.0±363.5 613.1±329.4 Relative (impacts.min-1) 8.2±5.2 9.7±6.1 10.2±5.5 Significant differences are identified as: (a) U15 vs. U17; (b) U15 vs. U19; (c) U17 vs. U19. Post-hoc a,b,c a,b,c a,c b,c c a,b a,b The figure 4.1a presents the variation of distance covered at the considered speed zones for each group. There was a significant effect of speed zones (F=6495.5, p<.001, 113 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 2=.92, Power=1.00), with pairwise differences between all zones. Also, the interaction between speed zones and players’ age groups was significant (F=22.1, p<.001, 2=.07, Power=1.00). The heart rate values (see figure 4.1b) showed significant effects of zones (F=575.7, p<.001, 2=.49, Power=1.00) and interaction with age groups (F=9.7, p<.001, 2=.03, Power=1.00) with pairwise differences between all zones. The players spent most of time below 75% HRmax. The Figure 4.1c presents the number of impacts in the six considered G force zones. There was a significant effect of zone (F=1936.6, p<.001, 2=.76, Power=1.00) with pairwise differences in all zones. Additionally, differences were found (F=4.8, p<.01, 2=.02, Power=1.00) between U15 and U17 and between U15 and U19. The players performed a higher number of impacts in zone 1 (<5.0–6.0g). Finally, the figure 4.1d presents the distance covered at high/very high, moderate and low speed zones for each 100 meters covered in the very low-activity zone. The results showed significant differences in the high/very high intensity activity (F=11.8, p<.001) and moderate intensity activity (F=15.07, p<.001), between U19 and both U17 and U15. No differences were found in low/very low activity. 114 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Figure 4.1. Results from distance covered for each speed zone (a), time spent in each heart rate zone (b), number of impacts for each intensity zone (c) and distance in different intensity zones for each 100m covered at very low intensity (d). The table 4.3 presents the mean intersection coefficient of variation (%) between age groups. Significant differences were found (p<.05) in distances covered for zones 1, 5 and 6 between U17 and U19. HR presented significant differences (p<.05) for zones 2 and 3 between U15 and U19. Also, the variability in the number of sprints performed was different (p<.05) between U17 and U19. Table 4.3. Mean intersection Coefficient of variation (%) according to the age groups. Variables U15 U17 U19 Post-hoc Distance covered Zone 1 16.28 12.63 16.06 b Zone 2 29.75 37.05 25.36 Zone 3 33.73 38.90 34.12 Zone 4 37.75 36.83 43.10 Zone 5 44.10 32.80 52.12 b Zone 6 64.60 47.33 67.52 b Total 17.33 16.83 19.58 Heart Rate Zone 1 33.10 36.18 35.36 Zone 2 36.68 35.63 40.36 a Zone 3 46.18 47.05 73.76 a Zone 4 78.05 77.70 105.66 Sprint Number 57.20 42.98 69.16 b Time interval 32.13 30.58 39.42 Distance covered 34.18 32.13 40.76 Impacts zone Zone 1 53.28 55.33 48.60 Zone 2 65.28 62.53 57.00 Zone 3 73.93 68.75 59.40 Zone 4 80.00 75.13 69.24 Zone 5 91.03 94.45 86.04 Zone 6 127.48 126.65 127.44 Total 61.45 59.25 56.80 Significant differences are identified as: a) between U15 and U19; b) between U17 and U19. 4.1.5. Discussion This study aimed to describe time-motion and physiological profiles of TS performed by under 15, under 17 and under 19 players competing in the Portuguese national championship. Previous research has been exclusively focused on monitoring specific 115 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ moments of practice sessions or drills in highly controlled situations using constrainedtasks20. However, in order to improve ecological validity it seems important to monitor and describe the total physiological workload imposed by the regular training process without any external manipulation. Results showed high variability between training sessions, refraining from identifying meaningful trends when measuring performance but, alternatively, it might also be consider that this variability is functional and constitutes a key-characteristic of elite training sessions21. The distances covered for all age groups confirm the diversity of stimulus promoted during a football practice session, probably by including technical, tactical and physical drills with diverse aims, variable intensity and volume loads9. The coefficient of variation (%) according to age groups showed higher values in distances covered, HR and number of sprints for U19 players. Probably, the focus on team tactical principles required additional coaching intervention, promoting more task interruptions across the training sessions and eliciting variability. Consequently, the lower effect sizes across variables may also be linked to this high variability. Nevertheless, the focus on constrained small-sided games to develop basic tactical principles and technical skills during U15 TS probably promoted a more regular activity pattern and resulted in the lowest variability among the age groups. The results of the present study suggest coaches to establish short and mid-term planning guidelines corresponding to elite demands in youth football players. Unfortunately, only a comprehensive description of practice sessions’ tasks could be carried. Thus, the impossibility of manipulating the training contents implies caution on the practical application of the results. Yet, the general idea from the results points that football game-based training in these age groups has different consequences. Although speculative, it is likely that the U15 training is less physiologically demanding, probably because of the time spent in learning technical skills and basic tactical principles in short-dimension pitches. The U17 age group gathers players with increased biological maturation, capable of responding to higher power and speed demands during the frequent game-like situations. Finally, the U19 constrained small-sided games focused on team tactical principles may be linked to the decrease of the physiological demands. Still, considering different age groups may have impaired an accurate control of the players’ maturational status. 116 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ The external load was already described according to playing positions by using distances covered during match-play22 and running velocities in treadmill protocols23. Although it is known that the physiological demands may vary according to playing position24, available literature does not clarify the variations that might exist both among different age groups and during training situations. The short term planning of the three age groups was established by coaches, based on technical and tactical needs in each one of the age groups. The U15 TS were mainly focused on constrained smallsided games directed to the development of the basic tactical principals and technical skills, which can help justifying the lower distance covered. These training guidelines are in accordance with the long-term athlete development plans for this age group, reinforcing the importance of deliberate practice based on targeted and task centred training programs25. Comparatively to U15, the use of frequent game-like situations during U17 and U19 TS can support the higher covered distances. In particular, the U17 players covered the highest total and relative distances and had the highest number of sprints. The use of game-like situations played with fewer constraints helped to increase physiological stimulus. On the other hand, the small-sided games training used in U19 practice sessions might have more stopping times to adjust the teams’ tactical model. In fact, the U19 high/very high:very low and moderate:very low work ratios presented the lowest values. This lack of high intensity activity may compromise the replication of the physiological pattern required in elite competition, as described by early available research7,9,26. In all age groups, the players covered higher distances in the first four speed zones (between 0-6.9 km.h-1) and players spent the highest amount of time below 75% HRmax. A previous study focused on the distances covered at different running speeds during a young football match found that players covered the highest distances between 0-6.0 km.h-1 and the lowest above 21.1 km.h-1 22 . However, the time spent above 180 b.min-1 intervals was higher than below 180 b.min-1 22 . Although the external load imposed on young players during training is similar to those verified during a match play, the average HR values during matches is substantially higher than those found in practice sessions. In the U17 and U19 sessions, the frequent use of game like situations elicited a higher number of sprints. The use of constrained small-sided games aiming to the basic tactical principles and technical development during U15 TS resulted in lowest 117 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ distances covered below 9.9 km.h-1. Thus, coaches should be aware that the replication of the competition physiological pattern may be compromised if TS do not include more game-like situations to promote higher intensities and variability13,27,28. Although football is an invasion team sport with frequent contact, the activity profile does not seem to promote a high occurrence of impacts. In the current study, the average number of total impacts identified during the football-TS was of 471±291.5, 563±350.7 and 572±325 for U15, U17 and U19 players, respectively. Of interest is, however, the significant difference identified between the U15 practices and the other groups. In fact, when game situations are frequently used, the higher occurrence of specific football actions such as changes of directions29,30 may increase the number of impacts and consequently the strength and power demands. 4.1.6. Practical Applications High variability between training sessions can be a key-characteristic of elite teams’ training sessions. The constrained small-sided games used to develop the basic tactical principles and technical skills during TS promoted a decrease of the physiological demands. In order to promote an increase in external and internal workload, coaches should frequently use game like situations. Youth football coaches can use these reference data to establish accurate short and mid-term planning guidelines corresponding to elite demands in youth football players for practice sessions. 4.1.7. Conclusion The high variability between training sessions might refrain from identifying meaningful trends, however, it might also be consider that this variability is functional and constitutes a key-characteristic of elite training sessions. The external load imposed on players differed in accordance with the age group. The U15 TS promoted less physiological demands because of the focus on the small-sided games aiming to the development of basic tactical principles and technical skills. Conversely, the frequency of game like-situations was higher during U17 and U19 sessions that imposed a higher 118 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ and more variable external load to the players. In addition, the use of game situations during football TS seems to increase the number of impacts, resulting in activity patterns that is more similar to the competition requirements. From a practical point of view, coaches seem to be aware of the importance of the technical abilities development at earlier age stages. Also, more game situations are promoted as biological maturation increases. As the age groups progress, football coaches may plan the TS more similar to the formal game physical, technical, and tactical demands. Acknowledgements This study was supported by PTDC/DES/098693/2008 project: “Evaluating training and competition in team sports. Aggregating tactical analysis, external and internal workload” financed by the Portuguese Foundation for Science and Technology (FCT). 119 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 4.1.8. References 1. Rebelo A, Brito J, Seabra A, Oliveira J, Krustrup P. Physical match performance of youth football players in relation to physical capacity. Eur J Sport Sci. 2012:1-9. 2. Wrigley R, Drust B, Stratton G, Scott M, Gregson W. Quantification of the typical weekly in-season training load in elite junior soccer players. J Sport Sci. Aug 1 2012. 3. Bangsbo J. The physiological profile of soccer players. Sports Exerc Injury. Nov 1998;4(4):144-150. 4. Impellizzeri FM, Marcora SM, Castagna C, et al. Physiological and performance effects of generic versus specific aerobic training in soccer players. Int. J. Sports Med. Jun 2006;27(6):483-492. 5. Williams AM, Hodges NJ. Practice, instruction and skill acquisition in soccer: challenging tradition. J Sport Sci. Jun 2005;23(6):637-650. 6. Coutts A, Rampinini E, Marcora S, Castagna C, Impellizzeri F. Heart rate and blood lactate correlates of perceived exertion during small-sided soccer games. Journal of Science and Medicine in Sport. 2009;12:79-84. 7. Mohr M, Krustrup P, Bangsbo J. Match performance of high-standard soccer players with special reference to development of fatigue. J Sport Sci. 2003;21(7):519-528. 8. Hill-Haas SV, Coutts AJ, Dawson BT, Rowsell GJ. Time-motion characteristics and physiological responses of small-sided games in elite youth players: the influence of player number and rule changes. J Strength Cond Res. Aug 2010;24(8):2149-2156. 9. Bangsbo J, Mohr M, Krustrup P. Physical and metabolic demands of training and match-play in the elite football player. J Sport Sci. Jul 2006;24(7):665-674. 10. McLellan CP, Lovell DI, Gass GC. Biochemical and endocrine responses to impact and collision during elite rugby league match play. J Strength Cond Res. Jun 2011;25(6):1553-1562. 120 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 11. Castellano J, Casamichana D, Calleja-Gonzalez J, San Roman J, Ostojic SM. Reliability and accuracy of 10 Hz GPS devices for short-distance exercise. J Sport Sci Med. Mar 2011;10(1):233-234. 12. Aguiar M, Botelho G, Goncalves B, Sampaio J. Physiological responses and activity profiles of football small-sided games. J Strength Cond Res. Jul 18 2012. 13. Casamichana D, Castellano J, Castagna C. Comparing the physical demands of friendly matches and small-sided games in semiprofessional soccer players. J Strength Cond Res. 2012. 14. Cunniffe B, Proctor W, Baker JS, Davies B. An evaluation of the physiological demands of elite rugby union using global positioning system tracking software. J Strength Cond Res. Jul 2009;23(4):1195-1203. 15. Gore C. Physiological Tests for Elite Athletes. Champaign, IL.: Human Kinetics; 2000. 16. Krustrup P, Mohr M, Nybo L, Jensen JM, Nielsen JJ, Bangsbo J. The Yo-Yo IR2 test: Physiological response, reliability, and application to elite soccer. Med Sci Sport Exer. Sep 2006;38(9):1666-1673. 17. Bangsbo J, Iaia FM, Krustrup P. The yo-yo intermittent recovery test - a useful tool for evaluation of physical performance in intermittent sports. Sports Med. 2008;38(1):37-51. 18. Montgomery PG, Pyne DB, Minahan CL. The physical and physiological demands of basketball training and competition. Int J Sports Physiol Perform. Mar 2010;5(1):75-86. 19. Hopkins WG. Measures of reliability in sports medicine and science. Sports Med. Jul 2000;30(1):1-15. 20. Hill-Haas S, Dawson B, Impellizzeri F, Coutts A. Physiology of small-sided games training in football a systematic review. Sports Med. 2011;41(3):199-220. 21. Davids K, Glazier P, Araujo D, Bartlett R. Movement systems as dynamical systems: The functional role of variability and its implications for sports medicine. Sports Med. 2003;33(4):245-260. 121 Capítulo 4 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 22. Aslan A, Acikada C, Guvenc A, Goren H, Hazir T, Ozkara A. Metabolic demands of match performance in young soccer players. J Sport Sci Med. Mar 2012;11(1):170-179. 23. Guner R, Kunduracioglu B, Ulkar B. Running velocities and heart rates at fixed blood lactate concentrations in young soccer players. Adv Ther. May-Jun 2006;23(3):395-403. 24. Dellal A, Wong D, Moalla W, Chamari K. Physical and technical activity of soccer players in the French first league - with special reference to their playing position. Int Sportmed J. 2010;11(2):278-290. 25. Memmert D, Baker J, Bertsch C. Play and practice in the development of sportspecific creativity in team ball sports. High Abil Stud. 2010;21(1):3-18. 26. Rienzi E, Drust B, Reilly T, Carter JE, Martin A. Investigation of anthropometric and work-rate profiles of elite South American international soccer players. The Journal of Sports Medicine and Physical Fitness. Jun 2000;40(2):162-169. 27. Carling C, Dupont G. Are declines in physical performance associated with a reduction in skill-related performance during professional soccer match-play? J Sport Sci. Feb 2011;29(1):63-71. 28. Castagna C, Impellizzeri FM, Chaouachi A, Bordon C, Manzi V. Effect of training intensity distribution on aerobic fitness variables in elite soccer players: a case study. J Strength Cond Res. Jan 2011;25(1):66-71. 29. Gabbett TJ, Sheppard JM, Pritchard-Peschek KR, Leveritt MD, Aldred MJ. Influence of closed skill and open skill warm-ups on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sport athletes. J Strength Cond Res. Sep 2008;22(5):1413-1415. 30. Varley MC, Aughey RJ. Acceleration profiles in elite Australian soccer. Int. J. Sports Med. Aug 15 2012. 122 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ CAPÍTULO 5 123 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 5.1. HELPING COACHES TO CLASSIFY YOUNG FOOTBALLERS ACCORDING TO THEIR TRAINING PERFORMANCES Eduardo Abade1, Bruno Gonçalves1, Alexandra Silva1, Nuno Leite1, Carlo Castagna2 and Jaime Sampaio1 1 University of Trás-os-Montes e Alto Douro, Research Center in Sport Sciences, Health and Human Development (CIDESD). Vila Real, Portugal. 2 Football Training and Biomechanics Laboratory, Italian Football Federation (FIGC), Technical Department, Coverciano (Florence), Italy. 5.1.1. Abstract This study aimed to classify young footballers according to their physical and physiological profiles in training sessions (TS) and to contrast this classification procedure against the age and playing position criteria. 151 male elite football players of under 15, under 17 and under 19 years old stages participated in this study over a 9week period. Time-motion and body impact data were collected using GPS technology with heart rate monitored continuously across 38 randomly selected TS. The results demonstrated that players with identical ages and playing experience may have very different performance profiles. This method may provide helpful criteria to group players and diminishes the variability of the physiological outcomes, allowing coaches to have an accurate control on players’ responses. Key words: football, cluster analysis, performance profiles. 124 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 5.1.2. Introduction The competition in many youth team sports is organized according to several age groups, mostly because of the need to enhance educational and fair-play values. Although generally accepted, this organization form may fail to consider differences in chronological age, since players within the same age group can have very distinct physical and physiological profiles (Cobley, Baker, Wattie, & McKenna, 2009). The identification and description of these profiles may provide valuable information to refine the training workloads, task designs and environmental constraints. During adolescence, the playing positions and selection level (i.e., Regional, National) have an important interactive effect in players’ characteristics (Till, Cobley, O'Hara, Chapman, & Cooke, 2012). In fact, most motor skills experience significant developments during the pubertal period, reinforcing the importance of specific training (Fernandez-Gonzalo et al., 2010). Therefore, the coaches should regularly track the progression of players’ responses to training and competition, considering the interaction between ages and playing positions. From a physiological perspective, understanding the development of athletic potential alongside biological growth is crucial to select appropriate training aims at different stages of players’ development. The long-term athlete development models generally encourage the use of a wide range of activities in the earlier ages with a progressive narrowing of sport focus in more advanced ages (Côté & Fraser-Thomas, 2007). However, aiming for the most sensitive development periods seems to be a very delicate issue, partly because the long-term effects of youth intensive training and competitive schedules are poorly explored by literature. To develop a successful sports career, young players have to perform adequately in several dimensions (Elferink-Gemser, Visscher, Lemmink, & Mulder, 2004). Generally, the training sessions have a strong focus on game like situations, eliciting both dynamic and adaptive responses, providing high variability of physiologic, technical and tactical stimulus (Pinder, Davids, & Renshaw, 2012). However, the manipulation of constraints can be quite limited because, even if the task constraints contain relevant information for learning a specific activity, the unique characteristics of each learner also represent personal constraints (Chow et al., 2006). In fact, it is possible to identify that individual learning dynamics will be different since the interacting configurations of constraints 125 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ will differ between learners (Chow, Davids, Hristovski, Araujo, & Passos, 2011). Consequently, when physiological profiles vary among players, caution should be applied in data interpretation, mainly because of the differences in emergent behaviors. Therefore, it is dysfunctional to establish universal optimal learning pathways to which all learners should adhere. The presence of instabilities in the perceptual-motor landscape related to differences in growth, development, maturation and learning might provide qualitative changes in their performance (Hristovski, Davids, Araujo, & Passos, 2011). Within the available literature, the activity profiles of young football players are usually described in relation to playing positions (Aslan et al., 2012; Buchheit, MendezVillanueva, Simpson, & Bourdon, 2010) and age groups (Fernandez-Gonzalo et al., 2010; Till et al., 2012). For example, it was showed that running performance tends to increase with age (Buchheit et al., 2010) and youth players cover from 4435 to 8098m during a match (Rebelo, Brito, Seabra, Oliveira, & Krustrup, 2012). The players seem to cover the highest distances in low speed zones (0-6.0 km.h-1) and the lowest above 21.1km.h-1 (Aslan et al., 2012). The distances covered vary according to playing positions, with defenders and midfielders achieving the lowest and highest distances, respectively (Buchheit et al., 2010). The defenders seem to have lower endurance performances than midfielders and forwards (Markovic & Mikulic, 2011). The differences in movement and activity patterns require for different conditioning and recovery programs according to age and positional groups (Quarrie, Hopkins, Anthony, & Gill, 2012) because football demands for hard accelerations and decelerations, changes of direction and collisions. Therefore, the players’ body impact activity and HR profiles will help to better understand and assess the physical demands as well as to adjust rest and recover times after training and matches (Quarrie et al., 2012). Highlevel players are frequently required to perform high intensity sprints and changes of direction which underlines agility as a key ability (Sheppard & Young, 2006). Consequently, the development of changing direction related mechanisms, such as the sprinting capacity (Jones, Bampouras, & Marrin, 2009), power and strength qualities is a major issue to coaches and considered an important predictor of performance (P., Chan, & Smith, 2012). All these variables seem important to describe the players’ physiological profile and to provide key information to adjust the training load. However, these were really never 126 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ contrasted against the players’ actual internal load in training. The data gathered in training sessions can also be used to classify the players into different groups of performance, alternatively to different groups of ages and playing positions. In fact, physiological variables are suggested to be powerful predictors to identify talent in youth sports (Unnithan, White, Georgiou, Iga, & Drust, 2012). In this sense, the classification techniques (e.g., cluster analysis) based on physiological profiles may provide useful information for establishing groups of interest for talent identification and training prescription. Therefore, the aim of this study was to classify young footballers according to their physical and physiological profiles in training sessions and to contrast this classification procedure against the age and playing position criteria. In addition, we aimed to identify the most powerful variables in players’ classification. The improvements in these classification procedures will allow the sports clubs and coaches to improve the accuracy of training plans and the improvement in players’ interactions along the training tasks. Hypothesis 1. It is expected to find different performance profiles among players with identical ages and playing experience. Hypothesis 2. We hypothesized that heart rate values and body impacts would represent the most powerful predictors to discriminate performance profiles in training. 5.1.3. Method 5.1.3.1.Participants One hundred and fifty-one male football players of under 15 (U15 n=56), under 17 (U17 n=66) and under 19 (U19 n=29) years old stages participated in this study. The participants were part of five different elite youth teams, training and competing regularly in the Portuguese national competition (2011/2012 season). After a detailed protocol explanation about the aims, benefits and risks involved in this investigation, all participants, parents and coaches signed a written informed consent. Additionally, players were informed that they were free to withdraw from the study at any time without any penalty. The study protocol was conformed to the declaration of Helsinki 127 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ and was approved by the ethics committee of the Research Center in Sport, Health and Human Development (Vila Real, Portugal). 5.1.3.2.Procedures The study was conducted during the competitive season over a 9-week period (December to February) with 38 randomly chosen training situations (U15 n=12, U17 n=16 and U19 n=10) representing a total of 612 cases. All the practice sessions were performed at the same time period of the day (from 16.30h to 21.00h) in outdoor natural turf pitches, under similar environmental conditions (temperature 14–19°C, relative humidity 52–66%). Both U15 and U17 teams trained four times per week for a total of 360 minutes in a 60x40 meters pitch, while U19 teams trained five times per week for a total of 450 minutes in a pitch with official dimensions. Besides the regular physical education classes, none of the players was involved in other sports. The average number of players per training unit was 23±4. All practice sessions started with a specific warm up that included low intensity running and ball possession drills. Stretching exercises were performed at the end of each training session. Players were allowed to drink water during specific recovery periods were allowed (approximately 3 minutes). The clubs and coaches authorized to perform only a comprehensive general description of practice sessions’ used drills. All sessions began with a ~15 minute warm-up and ended with ~10 minutes of cool down exercises. The U15 training sessions mainly included the development of technical skills and elementary tactical principles. Although the specific goals of U17 practices remained similar to U15, there was an increased focus in game-like situations. The U19 training sessions included constrained small-sided games focused on team tactical principles and physical conditioning stimulus. The players’ external workload was represented by the median values from all monitored training units. The distance covered was measured in predefined speed zones (Aguiar, Botelho, Goncalves, & Sampaio, 2012): zone 1 (0.0-6.9 km.h-1), zone 2 (7.09.9 km.h-1), zone 3 (10.0-12.9 km.h-1), zone 4 (13.0-15.9 km.h-1), zone 5 (16.0-17.9 km.h-1) and zone 6 (≥18.0 km.h-1). Sprints (zone 6) were also measured by both average time interval and distance covered. The data were collected at 15Hz through the entire duration of each training sessions using portable global positioning system units (SPI128 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ PRO X II, GPSports, Canberra, ACT, Australia). These units were fitted to the upper back of each participant using an appropriate elastic harness. The validity and reliability of these instruments were already inspected by independent verifications for the both 5 and 10Hz units (Castellano, Casamichana, Calleja-Gonzalez, San Roman, & Ostojic, 2011; Johnston et al., 2012). Players’ internal workload included the HR and the body impacts variables. The HR absolute values were recorded continuously throughout all training sessions using the Polar Team System (Polar Electro, Oy, Kempele, Finland) and, subsequently, converted into percentages of HRmax and classified into time spent in four zones of intensity (Gore, 2000): Zone 1 (<75% HRmax), Zone 2 (75-84.9 % HRmax), Zone 3 (85-89.9 % HRmax) and Zone 4 (≥ 90 % HRmax). To measure the players’ HRmax, the Yo-Yo intermittent recovery level 2 test was performed (Krustrup et al., 2006). The SPI-PRO X II units are coupled with a 100Hz accelerometer capable of measuring the body impacts thought the rate of acceleration and deceleration ability in horizontal axis (x), transverse axis (y) and vertical axis (z). This variable measures the changes of direction, collisions with opposition and the ground. The values were grouped into six zones of G force (McLellan, Lovell, & Gass, 2011): zone 1 (very light impact, <5.0–6.0g), zone 2 (light to moderate impact, 6.1-6.5g), zone 3 (moderate to heavy impact, 6.5-7.0g), zone 4 (heavy impact, 7.1-8.0g), zone 5 (very heavy impact, 8.1-10.0g) and zone 6 (severe impact, >10.1g). 5.1.3.3.Analysis A two-step cluster with log-likelihood as the distance measure and Schwartz’s Bayesian criterion was performed to classify athletes according to their performance profiles (i.e. all variables described in procedures section). The considered analysis was used to point out physical and physiological similarities among players. This method differs from traditional clustering techniques by handling of categorical variables (assuming variables to be independent), automatic selection of number of clusters (automatically determines the optimal number of clusters) and scalability (by constructing a cluster membership) (Tabachnick & Fidell, 2007). The variables were ranked according to their predictor importance, indicating the relative importance of each predictor in estimating the model (the sum of the values for all predictors on the display is 1). Subsequently, 129 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ the clustering variables description was presented as means ± standard deviations. The sprint activity variables were tested using one-way ANOVA. Finally, a repeated measures factorial ANOVA was performed to identify differences in time motion, HR and body impact zones according to the clustering groups. Pairwise differences were assessed with Bonferroni post-hoc test. All data sets were tested for each statistical technique corresponding assumptions. These calculations were carried in SPSS Software (v20.0, IBM Corporation, USA) and statistical significance was maintained at .05. 5.1.4. Results The cluster analysis classified the players into three distinct groups in accordance with their physical and physiological performances during the training sessions. The obtained clusters comprised, respectively, 15.2%, 37.1% and 47.7% of the total sample size. No differences were found in players’ age, height, weight, BMI and experience between the clusters (see table 5.1). Table 5.1. Characterization of the cluster groups. Age Height Weight BMI Experience Cluster 1 (n=23) Cluster 2 (n=56) Cluster 3 (n=72) 15.7±1.5 1.72±0.06 63.2±5.6 21.3±1.4 6.5±1.9 15.4±1.0 1.76±0.07 65.1±6.2 21.0±1.3 6.8±1.7 15.5±1.7 1.74±0.07 64.5±7.7 21.2±1.6 6.7±2.3 The figure 5.1 shows the distribution (%) of players in each Cluster considering the players’ actual development stage and playing position. The Cluster 1 presents the lowest percentage of sample size, with a high presence of U19 midfielders, comparatively with the other age groups and playing positions. The Cluster 2 includes the highest percentage of U17 players and the lowest percentage of U19 players. The Cluster 3 is the group with higher size. The percentage of U15 forwards and defenders is high, as well as U19 midfielders and defenders. 130 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Figure 5.1. Distribution (%) of players in each cluster considering the players’ development stage and playing position Sprints characteristics (activity performed above 18 km.h-1) presented differences between clusters 2 and 3 for both time interval (F=11.7, p<.001) and distance covered per sprint (F=11.6, p<.001). The cluster 3 presented the lowest average time interval (1.67±0.24 seconds) and distance covered per sprint (9.45±1.43 meters). The figure 5.2 presents the results from both external and internal workload across clusters and also the predictor importance (PI) from all considered variables. Figure 5.2i presents the variation of distance covered at the considered speed zones for each cluster. There was a significant effect of both speed zones (F=2573.3, p<.001, η2=.95) and clusters (F=3.3, p<.001, η2=.43). Also, differences were found in body impacts zones (F=1020.8, p<.001, η2=.87) and clusters (F=44.1, p<.001, η2=.37), with pairwise differences across all groups, except between clusters 2 and 3 for zone 6 (see figure 5.2ii). The HR zone values showed significant effect of zones (F=487.1, p<.001, η2=.77) and clusters (F=30.9, p<.001, η2=.30) with players spending most of the time 131 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ below 75% of HRmax (see figure 5.2iii). Finally, figure 5.2iv presents the obtained predictor importance from the variables. The strongest PI was found in body impacts for zones 5 (PI=1.00), 3 (PI=0.88), 4 (PI=0.85) and 2 (PI=0.85). Distance covered at zone 1 was identified as the lowest PI (PI=0.03). Figure 5.2. Results from distance covered for each speed zone (i), number of impacts for each intensity zone (ii) time spent in each heart rate zone (iii) and predictor importance to all considered variable (iv). Significant differences are identified as: (a) Cluster 1 vs. Cluster 2; (b) Cluster 1 vs. Cluster 3; (c) Cluster 2 vs. Cluster 3 132 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 5.1.5. Discussion This study aimed to identify the most powerful performance predictors in clustering young footballers during training sessions, providing more accurate information about the players’ response to training stimulus. The obtained clusters were very similar in aging, anthropometric characteristics and experience years. This similarity suggests that these variables may not be the most important to discriminate the performance profiles in training. In general, the current results demonstrated that players with identical ages and playing experience might have very different physiological profiles and, consequently, respond in different ways to similar training stimulus. Some predictors such as anthropometric and physiological characteristics have recently been suggested to identify talent in youth sports and may represent useful information to predict future career progression (Unnithan et al., 2012). Thus, the clustering methods can provide performance profiles to enable early identification of talented youths. Also, grouping players with similar physiological characteristics may diminish the emergence of heterogeneous responses during training, which can help coaches in the distribution of training groups and allow an efficient control on the players’ response. Moreover, clustering may be performed by using valuable information from fitness tests, which allow coaches to manipulate these profiles in any moment of the competitive season. The current results identified that body impacts in higher intensity zones (zones 2 to 5) were the predictors that best discriminated the obtained clusters. Although the training tasks were similar across all age groups, the players’ responses in body impacts varied substantially across the clusters. This importance may suggest that selected task constraints in training enhance a specific learning, exhibited in players’ unique rates of acceleration and deceleration. Sprints with changes of direction seem to induce a higher neuromuscular stimulus than intermittent in-line sprints (Dellal et al., 2010), mostly because of its high relationship with the eccentric strength (Jones et al., 2009). The results show that players in cluster 1 performed a higher number of impacts across all zones. This analysis may help coaches to identify the most capable players to successfully perform high intensity and rapid body movements. It seems that these data is important to understand and measure the performance indicators of the high intensity intermittent exercises, frequently experienced during training and/or game situations (Vaz, Leite, Vicente, Gonçalves, & Sampaio, 2012). These results present a new insight 133 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ to the process of monitoring training effects, by including body impacts as key variable to understand the players’ individuals’ responses to different task designs. The Cluster 3 represented the players with lower distances covered and body impacts across all zones per training. Consequently, these players spent more time below 75% HRmax. This is the most frequent profile (47.7% of sample size), including a high percentage of U15 and U19 players, probably because of the players’ fitness, maturity and status level. It was suggested that higher expertise, positioning and deciding skills (Kannekens, Elferink-Gemser, & Visscher, 2011) might result in lower physical and physiological intensity for U19 players. In fact, high-level U19 coaches usually focus their attention on the team strategic plans and collective tactical responses, by improving players’ positioning. The U15 training sessions have a different perspective, mainly focused on acquiring basic collective tactical principles such as the interpersonal player relations in sub-phases (Duarte et al., 2012). Consequently, the frequent presence of U15 players in cluster 3 may be the result of lower conditioning variables, such as strength, power and speed (Malina, Eisenmann, Cumming, Ribeiro, & Aroso, 2004). The Cluster 2 has a frequent number of U17 players that is beyond the critical period of physical maturation in an intermediate stage of tactical expertise. Also, the progressive understanding of the game collective tactical principles potentiated by the training process may be responsible for the intermediate physiological profile of these players. The Cluster 1 represented the players within higher values across all variables, but with the lower number of players. It might be suggested that these players should be followed with increased attention because they exhibit the higher physical and physiological potential. When training tasks are focused on the players’ physical development, grouping players with similar physiological profiles and fitness level may avoid significant divergent responses and adaptations to the stimulus. Thus, coaches would have a more accurate and effective control on the players’ response exercises, mainly during specific blocksperiodized training (Issurin, 2010). However, optimal performance in competitions requires not only the physiological development, but also the technical and tactical abilities. In this sense, caution should be applied when game-like situations are promoted due to the players’ different perceptual-cognitive expertise. Yet, further investigations are required to explore the short and long-term effects of this clustering method. 134 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Similarity in aging, anthropometric characteristics and experience years in the studied groups, suggest that these variables are not the most important to discriminate the performance profiles in training. The players’ unique activity profiles suggested a specific learning effect, as identified by body impacts resulting from players’ accelerations and decelerations in sprints with changes of direction. The body impacts seem to be powerful predictors to represent players’ performance profiles in training sessions. As physiological variables are suggested to be important predictors to identify talent in youth sports, using them to establish cluster classifications may provide reference profiles to early talent identification. Also, this classification technique may help coaches to optimize player distribution in training groups during the practice sessions. Consequently, this approach minimizes the variability of the physiological outcomes, allowing coaches and fitness trainers to accurately manipulate the training exercises and have a more effective control on the players’ responses. Thus, coaches should not hinder mixing up players with different ages and playing positions in order to optimize their adaptations to training stimulus. 135 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 5.1.6. References Aguiar, M., Botelho, G., Goncalves, B., & Sampaio, J. (2012). Physiological responses and activity profiles of football small-sided games. Journal of Strength and Conditioning Research. doi: 10.1519/JSC.0b013e318267a35c Aslan, A., Acikada, C., Guvenc, A., Goren, H., Hazir, T., & Ozkara, A. (2012). Metabolic demands of match performance in young football players. Journal of Sports Science and Medicine, 11(1), 170-179. Buchheit, M., Mendez-Villanueva, A., Simpson, B. M., & Bourdon, P. C. (2010). Match Running Performance and Fitness in Youth Football. International Journal of Sports Medicine, 31(11), 818-825. doi: 10.1055/s-0030-1262838 Castellano, J., Casamichana, D., Calleja-Gonzalez, J., San Roman, J., & Ostojic, S. M. (2011). Reliability and accuracy of 10 Hz GPS devices for short-distance exercise. Journal of Sports Science and Medicine, 10(1), 233-234. Chow, J. Y., Davids, K., Button, C., Shuttleworth, R., Renshaw, I., & Araujo, D. (2006). Nonlinear pedagogy: a constraints-led framework for understanding emergence of game play and movement skills. Nonlinear Dynamics Psychol Life Sci, 10 (1), 71-103. Chow, J. Y., Davids, K., Hristovski, R., Araujo, D., & Passos, P. (2011). Nonlinear pedagogy: Learning design for self-organizing neurobiological systems. New Ideas in Psychology, 29(2), 189-200. doi: 10.1016/J.Newideapsych.2010.10.001 Cobley, S., Baker, J., Wattie, N., & McKenna, J. (2009). Annual age-grouping and athlete development a meta-analytical review of relative age effects in sport. Sports Medicine, 39(3), 235-256. Côté, J., & Fraser-Thomas, J. (2007). Youth Involvement in Sport. Toronto: Pearson Prentice Hall. Dellal, A., Keller, D., Carling, C., Chaouachi, A., Wong, D. P., & Chamari, K. (2010). Physiologic effects of directional changes in intermittent exercise in football players. Journal of Strength and Conditioning Research, 24(12), 3219-3226. doi: Doi 10.1519/Jsc.0b013e3181b94a63 Duarte, R., Araujo, D., Davids, K., Travassos, B., Gazimba, V., & Sampaio, J. (2012). Interpersonal coordination tendencies shape 1-vs-1 sub-phase performance 136 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ outcomes in youth football. Journal of Sports Sciences, 30(9), 871-877. doi: 10.1080/02640414.2012.675081 Elferink-Gemser, M. T., Visscher, C., Lemmink, K. A. P. M., & Mulder, T. W. (2004). Relation between multidimensional performance characteristics and level of performance in talented youth field hockey players. Journal of Sports Sciences, 22(11-12), 1053-1063. doi: Doi 10.1080/02640410410001729991 Fernandez-Gonzalo, R., De Souza-Teixeira, F., Bresciani, G., Garcia-Lopez, D., Hernandez-Murua, J. A., Jimenez-Jimenez, R., & De Paz, J. A. (2010). Comparison of technical and physiological characteristics of prepubescent football players of different ages. Journal of Strength and Conditioning Research, 24(7), 1790-1798. doi: 10.1519/Jsc.0b013e3181def871 Gore, C. (2000). Physiological Tests for Elite Athletes. Champaign, IL.: Human Kinetics. Hristovski, R., Davids, K., Araujo, D., & Passos, P. (2011). Constraints-induced emergence of functional novelty in complex neurobiological systems: A basis for creativity in sport. Nonlinear Dynamics, Psychology, and Life Sciences, 15(2), 175-206. Issurin, V. B. (2010). New horizons for the methodology and physiology of training periodization. Sports Medicine, 40(3), 189-206. Johnston, R., Watsford, M., Pine, M. J., Spurrs, R. , Murphy, A., & Pruyn, E. (2012). The validity and reliability of 5-hz global positioning system units to measure team sport movement demands. Journal of Strength and Conditioning Research. doi: 10.1519/JSC.0b013e318225f161 Jones, P., Bampouras, T. M., & Marrin, K. (2009). An investigation into the physical determinants of change of direction speed. J Sports Med Phys Fitness, 49(1), 97104. Kannekens, R., Elferink-Gemser, M. T., & Visscher, C. (2011). Positioning and deciding: key factors for talent development in football. Scandinavian Journal of Medicine & Science in Sports, 21(6), 846-852. doi: 10.1111/J.16000838.2010.01104.X 137 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Krustrup, P., Mohr, M., Nybo, L., Jensen, J. M., Nielsen, J. J., & Bangsbo, J. (2006). The Yo-Yo IR2 test: Physiological response, reliability, and application to elite football. Medicine and Science in Sports and Exercise, 38(9), 1666-1673. doi: 10.1249/01.Mss.0000227538.20799.08 Malina, R. M., Eisenmann, J. C., Cumming, S. P., Ribeiro, B., & Aroso, J. (2004). Maturity-associated variation in the growth and functional capacities of youth football (football) players 13-15 years. European Journal of Applied Physiology, 91(5-6), 555-562. doi: DOI 10.1007/s00421-003-0995-z Markovic, G., & Mikulic, P. (2011). Discriminative ability of the yo-yo intermittent recovery test (level 1) in prospective young football players. Journal of Strength and Conditioning Research, 25(10), 2931-2934. doi: 10.1519/Jsc.0b013e318207ed8c McLellan, C. P., Lovell, D. I., & Gass, G. C. (2011). Biochemical and endocrine responses to impact and collision during elite rugby league match play. Journal of Strength and Conditioning Research, 25(6), 1553-1562. doi: 10.1519/Jsc.0b013e3181db9bdd P., Wong D., Chan, G. S., & Smith, A. W. (2012). Repeated-sprint and change-ofdirection abilities in physically active individuals and football players: training and testing implications. Journal of Strength and Conditioning Research, 26(9), 2324-2330. doi: 10.1519/JSC.0b013e31823daeab Pinder, R. A., Davids, K., & Renshaw, I. (2012). Metastability and emergent performance of dynamic interceptive actions. J Sci Med Sport, 15(5), 437-443. doi: 10.1016/j.jsams.2012.01.002 Quarrie, K. L., Hopkins, W. G., Anthony, M. J., & Gill, N. D. (2012). Positional demands of international rugby union: Evaluation of player actions and movements. J Sci Med Sport. doi: 10.1016/j.jsams.2012.08.005 Rebelo, A., Brito, J., Seabra, A., Oliveira, J., & Krustrup, P. (2012). Physical match performance of youth football players in relation to physical capacity. European Journal of Sport Science, 1-9. doi: 10.1080/17461391.2012.664171 138 Capítulo 5 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Sheppard, J. M., & Young, W. B. (2006). Agility literature review: Classifications, training and testing. Journal of Sports Sciences, 24(9), 919-932. doi: Doi 10.1080/02640410500457109 Tabachnick, B. G., & Fidell, L. S. (2007). Using Multivariate Statistics (5 ed.). Boston: 18 Allyn and Bacon. Till, K., Cobley, S., O'Hara, J., Chapman, C., & Cooke, C. (2012). A longitudinal evaluation of anthropometric and fitness characteristics in junior rugby league players considering playing position and selection level. Journal of science and medicine in sport. doi: 10.1016/j.jsams.2012.09.002 Unnithan, V., White, J., Georgiou, A., Iga, J., & Drust, B. (2012). Talent identification in youth football. Journal of Sports Sciences. doi: 10.1080/02640414.2012.731515 Vaz, L., Leite, N., Vicente, J., Gonçalves, B., & Sampaio, J. (2012). Differences between experienced and novice rugby union players during small-sided games. Perceptual and Motor Skills, 115(2), 594-604. 139 Capítulo 6 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ CAPÍTULO 6 140 Capítulo 6 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 6.1. CONCLUSÕES E APLICAÇÕES PRÁTICAS O planeamento dos ciclos semanais de treino assume-se como um desafio para os treinadores, em parte pela complexidade que emerge da necessidade de combinar o treino das capacidades físicas com o aperfeiçoamento das habilidades técnico-táticas. Por um lado, o desenvolvimento da força muscular requer sessões de treino com intensidades específicas que induzam adaptações neuromusculares significativas. Por outro, a procura por estímulos fisiológicos e técnico-táticos de elevada intensidade e variabilidade faz com que os treinadores optem frequentemente por jogos reduzidos durante todo o ciclo anual. Neste sentido, o aprofundar de conhecimento nestes dois tópicos configuram um problema de grande interesse para o avanço do treino desportivo. Procurando dar resposta a este problema, a primeira parte deste trabalho foi constituída por dois estudos centrados nos efeitos agudos de unidades de treino de força na resposta fisiológica, percetual, ações técnico-táticas e impulsão vertical em sessões de treino de Andebol. Verificou-se que as unidades de treino de força precedentes a sessões de treino constituídas por jogos reduzidos induziram valores mais elevados de frequência cardíaca e perceção subjetiva do esforço. Mesmo com um número reduzido de jogadores (3x3), o treino de força promoveu aumentos do tempo passado em zonas elevadas de frequência cardíaca. Assim, a colocação de uma sessão de treino de força máxima antes de uma unidade de treino que inclua jogos reduzidos parece ser uma estratégia eficiente para o desenvolvimento da performance aeróbia em contexto de jogo. Apesar disso, os resultados mostram que a capacidade de salto diminuiu imediatamente após o treino de força máxima, com uma deterioração ainda mais significativa após os jogos reduzidos 3x3 com treino de força antecedente, provavelmente pela fadiga aguda e diminuição da potência muscular. Como consequência, o maior estímulo fisiológico verificado durante os jogos 3x3 pode afetar a eficiência de algumas ações técnico-táticas, sobretudo quando existe treino de força antecedente. Os jogos 3x3 parecem ser os mais indicados para o aumento da frequência de ações individuais e estabelecimento de um padrão de jogo mais imprevisível, embora as tomadas de decisão do jogador com bola pareçam estar limitadas. Por outro lado, os jogos 6x6 diminuíram o número de contactos individuais com a bola e aumentaram a variabilidade do estímulo, convergindo num padrão de resposta fisiológica mais 141 Capítulo 6 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ intermitente. Para além disso, o 6x6 aumentou o número de passes, receções e interceções, sugerindo uma maior interação e cooperação entre jogadores. Os valores de impulsão vertical após os jogos 6x6 foram, no geral, superiores aos verificados no momento após o treino de força. Assim, utilizar sessões de treino de força máxima antes de jogos 6x6 poderá aumentar a intensidade do estímulo sem prejuízo da eficiência técnico-tática. Para além dos efeitos da combinação de sessões de treino com múltiplos objetivos, a caracterização dos perfis de treino nos jogos desportivos coletivos é bastante omissa na literatura disponível. Em particular, a descrição dos perfis de performance em idades jovens é indispensável para um planeamento adequado e que respeite as necessidades que os jogadores apresentam nos seus diferentes estados de maturação. Mais, conhecer os critérios utilizados pelos treinadores na organização das sessões de treino pode ajudar a definir estratégias de planeamento que facilitem a deteção de talentos e a otimização da resposta fisiológica aos estímulos. Neste sentido, a segunda parte do presente trabalho focou-se na descrição de perfis físicos e fisiológicos de sessões de treino de futebol e na otimização da carga de treino através do estabelecimento de critérios para a classificação dos jogadores. Observou-se que a elevada variabilidade na resposta aos estímulos foi uma característica chave transversal a todos os escalões (sub-15, sub-17 e sub-19). Para além disso, os perfis de carga externa variaram em função da idade. As unidades de treino sub-15 focaram-se em jogos reduzidos dirigidos ao desenvolvimento de princípios técnico-táticos base, o que resultou na diminuição do estímulo fisiológico. Os jogadores sub-17 percorreram as maiores distâncias totais e em sprint, consequência de sessões de treino principalmente constituídas por jogos reduzidos pouco constrangidos. Os jogadores sub-19 registaram um perfil de atividade intermitente de baixa intensidade, em parte porque os exercícios de treino eram frequentemente interrompidos para que os treinadores pudessem ajustar o modelo tático da equipa. Na verdade, a crescente preocupação com os aspetos táticos do jogo pode comprometer o padrão fisiológico exigido durante as competições de elite. Caso pretendam aumentar a intensidade do estímulo, os treinadores deverão privilegiar mais situações de jogo pouco constrangidas. De um ponto de vista prático, os treinadores parecem estar cientes da importância do desenvolvimento das habilidades técnicas em idades mais jovens. À medida que a idade biológica avança, as situações de jogo parecem ser incluídas com mais frequência nas 142 Capítulo 6 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ unidades de treino, emergindo perfis técnicos, táticos e físicos mais próximos do padrão competitivo. A organização da maior parte das competições jovens baseia-se em critérios relacionados com a idade dos jogadores. Respeitando a linha destes modelos, muitos clubes e treinadores optam pela distribuição dos jogadores no treino em função do seu escalão etário. Foi sugerido um modelo de classificação alternativo a este método tradicional, apresentando alguns preditores de performance para o estabelecimento de grupos de treino homogéneos. No geral, os resultados demonstraram que jogadores com idades e anos de experiência idênticos podem apresentar perfis fisiológicos divergentes. Assim, a organização de grupos baseada em perfis físicos e fisiológicos semelhantes pode reduzir a variabilidade da resposta fisiológica e permitir a obtenção de informação mais precisa sobre a resposta dos jogadores aos estímulos de treino. Por esse motivo, os treinadores não deverão recear o agrupamento de jogadores com diferentes idades, anos de experiência e postos específicos durante as sessões de treino. Uma vez que as variáveis fisiológicas são sugeridas como preditores importantes na identificação de talentos, esta distribuição por grupos de performance também pode providenciar perfis de referência para a identificação de talentos em idades jovens. Os resultados desta tese apresentam dados com implicação direta no planeamento a curto prazo nos jogos desportivos coletivos. Os treinadores e preparadores físicos encontram nestes estudos informação que permite manipular, com critério, a organização de um ciclo semanal com sessões de treino dirigidas a múltiplos objetivos. A combinação entre o treino de força e o treino de campo sempre levantou algumas questões, que agora parecem um pouco mais claras. Quando o objetivo passa pelo desenvolvimento da performance aeróbia, o treino de força máxima pode ser combinado com sessões de campo, mesmo que estas sejam de intensidade elevada. Por outro lado, se o foco estiver dirigido para o aperfeiçoamento das habilidades técnico-táticas, as sessões de campo deverão privilegiar formas jogadas que proporcionem padrões de performance de maior variabilidade, como o 6x6. Neste caso, como a intensidade do estímulo é menor, o treino de força pode ser colocado antes da sessão de campo com o propósito de promover o aumento da intensidade sem prejuízo da performance técnicotática. Adicionalmente, esta tese faculta informação prática para que os treinadores possam selecionar as tarefas que melhor otimizam a resposta ao estímulo dos jogadores durante 143 Capítulo 6 ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ as sessões de campo. Quando os treinadores optam por tarefas dirigidas ao desenvolvimento de princípios técnico-táticos básicos, a carga externa de treino é mais reduzida. Por outro lado, se as situações de jogo forem privilegiadas com mais frequência, os perfis de performance irão aproximar-se do padrão competitivo, tanto mais quanto menores forem os constrangimentos. Complementarmente, o critério da idade tem que ser destituído como o mais importante na organização de uma sessão de treino. Caso contrário, jogadores com perfis de performance mais elevados poderão ter o desenvolvimento do seu potencial motor comprometido por um estímulo que não corresponde às suas necessidades. Assim, tanto a seleção das tarefas de treino como o seu modelo de organização parecem interferir nos perfis de carga dos jogadores. Em suma, esta tese disponibiliza informação prática para que o planeamento do microciclo semanal e das respetivas unidades de treino seja mais eficiente e adequado ao desenvolvimento da performance dos jogadores. Figura 6.1. Representação esquemática das principais aplicações práticas (resultados do presente trabalho). 144