Analisi computerizzata del movimento. Cinematica, cinetica ed

Analisi computerizzata del
movimento. Cinematica,
cinetica ed elettromiografia di
superficie
Eng. Massimiliano Mangone
Massimiliano Mangone
Human movement control is achieved by the
Central Nervous System by a complex, multilevel processing of peripheral signals.
In particular, the control of gait requires a
continuous assessment of proprioceptive
information aimed at adapting the locomotor
strategy to ensure dynamic balance, propulsion
and body weight support.
Therefore, Gait Analysis represents a useful
tool for investigating both myoneural and
biomechanical factors involved in walking.
Massimiliano Mangone
The main requirements of any techniques for human movement
measurement in the clinical practice are:
•Reliability:
‘the ability of a system to perform and maintain its
functions in routine circumstances’
•Standardization:
‘the act of checking or adjusting (by comparison with a
standard) the accuracy of a measuring instrument’
•Feasibility:
‘the quality of being doable’
Massimiliano Mangone
The sequence of events that must take place for
walking to occur may be summarized as follows:
1. Registration and activation of the gait
command in the central nervous system
2. Transmission of the gait signals to the
peripheral nervous system
3. Contraction of muscles that develop tension
4. Generation of forces at, and moments
across, synovial jonts
5. Regulation of the joint forces and moments
by the rigid skeletal segments based on
their anthropometry
6. Displacement of the segments in a manner
that is recognized as functional gait
7. Generation of ground reaction forces
Massimiliano Mangone
The Gait Analysis approach: motion of the mechanical system is defined in precise detail and
the objective is to determine the forces causing that motion.The key to understanding the way
in which human beings walk is integration. This means that we should always strive to
integrate the different components to help us gain a deeper insight into the observed gait.
Massimiliano Mangone
Massimiliano Mangone
Human Gait has a cyclic nature - The periodic leg movement is the essence of such a cycle.
Descriptions may be confined to a single cycle, with the assumption that successive cycles are all
about the same. Although this assumption is not strictly true, it is a reasonable approximation.
Massimiliano Mangone
Gait Cycle: begins when one of the feet makes contact with the ground.
There are two main phases in the gait cycle: During the stance phase, the foot is on the ground,
whereas in the swing phase that same foot is no longer in contact with the ground and the leg is
swinging through in preparation for the next foot strike.
Massimiliano Mangone
•Applicazione dei Markers: protocollo Davis
•Rilevazione Parametri Antropometrici
Massimiliano Mangone
Massimiliano Mangone
Kinematic Analysis
Data acquisition is performed by an infrared optoelectronic
system. The anlysis is based on the detection of the threedimensional coordinates and trajectories of passive markers
positioned on anatomical landmarks. Davis’ protocol
(1991) requires application of 22 markers.
Massimiliano Mangone
3d Analysis
Massimiliano Mangone
Parametri Spazio Temporali
Massimiliano Mangone
Parametri Cinematici
Cinematica: quella sezione della meccanica che descrive il movimento dei corpi
indipendentemente dalle cause che li producono, cioè indipendentemente dalle forze e che si
fonda essenzialmente sui concetti di spazio e di tempo
La definizione di cinematica può essere espressa come geometria del movimento analizzata sui
tre piani dello spazio.
Massimiliano Mangone
Parametri Cinematici
Descrizione del movimento dei
segmenti corporei e delle articolazioni
sul piano:
Sagittale
Frontale
Trasverso
Angoli rilevati nella prova di standing
Massimiliano Mangone
Dinamica o Cinetica: è il ramo della meccanica che si occupa dello studio del moto dei corpi
e delle sue cause o, in termini più concreti, delle circostanze che lo determinano e lo
modificano ed è regolata da tre principi o leggi:
•Legge I - Legge di inerzia di Galilei: Ciascun corpo persevera nel suo stato di quiete o di
moto rettilineo uniforme, salvo che sia costretto a mutare quello stato da forze impresse
•Legge II - Legge di Newton : Il cambiamento di moto è proporzionale alla forza risultante
motrice impressa, ed avviene lungo la linea retta secondo la quale la forza è stata impressa.
•Legge III - Ad ogni azione corrisponde una reazione uguale e contraria
Massimiliano Mangone
The Kinematics are the effects , but we are
also interested in studying the dinamic ,the
cause of the motion .
The joint forces and moments cause the rigid
skeletal links (segments such as
the thigh, calf, foot, etc.) to move and to exert
forces on the external environment.
In fact, angular kinematics and ground
reaction forces are all integrated to yield the
resultant joint forces and moments.
Massimiliano Mangone
Force Platform
The force platforms are devices fitted with sensors that
detect the forces acting when the subject strikes the
ground. The forces are analyzed along the three laboratory
axes to distinguish among the vertical, front-back and
median-side components.
The measured force, together with kinematic
analysis, allows studying moments and powers
for specific articulations
Massimiliano Mangone
Parametri Cinetici
Forze di Reazione al Suolo
Forza uguale e opposta che il suolo
esercita sul corpo durante la fase di
STANCE
Viene misurata la componente
Antero-posteriore (x)
Medio-laterale (y)
Verticale (di compressione - z)
Massimiliano Mangone
Parametri Cinetici
Forze di Reazione al Suolo
Vengono riferite al COP (centro di pressione) che
rappresenta il punto di applicazione del vettore
tridimesionale rappresentante la GRF
Massimiliano Mangone
Parametri Cinetici
Momento Interno
Prodotto della forza per la distanza dal
centro di rotazione articolare
Potenza
Prodotto del momento interno per la
velocità articolare
Massimiliano Mangone
Electromyography
The electromyographic analysis is the electrical representation of muscular
contraction. The muscular fibers, excited by the impulse from the nervous system,
contract. If two bipolar electrodes are applied on the surface of the skin, a variation
of the distribution of voltage potential can be detected during muscular contraction.
By recording this variation, a signal is obtained that represents the muscular activity
as a function of the movement being performed
Massimiliano Mangone
Electromyography
Data is thus obtained on the status of muscular activation specific to movement;
muscular activity is recorded by detailing sequence, time of activation, duration and,
within specific limits, the intensity, noninvasively. Particularly suited to gait
analysis, it also provides useful data about the processes of the central nervous
system that control the movement of the upper limb.
Massimiliano Mangone
Electromyography
Timing di attivazione durante le fasi del passo
Massimiliano Mangone
Electromyography
Indice di Fatica Muscolare: si ottiene applicando la trasformata di
Fourier. Si analizzano le armoniche principali che compongono il
segnale emg.
Massimiliano Mangone
Video Analysis
Complementary to kinematic analysis,
the video shoot of the subject provides
qualitative data that supports the clinical
investigation. Though it does not
provide numerical data, the video is a
permanent record of movement, useful
for repeated observation of the patient
by the physician, to document the
evolution of the motor performances and
possibly to provide the family and the
patient himself/herself with evidence of
progress and of the effectiveness of the
treatment, by an easily understandable
means.
Massimiliano Mangone
Upper Limb
8 markers retroreflettenti
Oggetto
C7
A2
• C7
A1
• Acromion destro
• Acromion sinistro
• Sacro
Gomito
• Epicondilo
•Stiloide ulnare
• Base del III metacarpo
• Oggetto
Polso
Mano
Sacro
Massimiliano Mangone
Massimiliano Mangone
Massimiliano Mangone
Studio della Coordinazione Toraco Pelvica
CRP: Continuous Relative Phase calcolato tra
cingolo scapolare e pelvico
Massimiliano Mangone
L’analisi del movimento nel
percorso clinico del paziente da
riabilitare
Massimiliano Mangone
In un test diagnostico le misure ottenute devono consentire
di distinguere fra pattern di movimento normali e patologici
e, inoltre, devono differenziare quadri patologici diversi.
Necessari sistemi di misurazione precisi
Necessario conoscere le caratteristiche di normalità di una data
misurazione
Massimiliano Mangone
"The approaches to clinical gait analysis and
evaluation are not supported by general theories“
(Cappozzo, 1982)
•
Il limite principale della nostra conoscenza riguardo il cammino è che questa è, allo stato
attuale, principalmente descrittiva. Siamo in grado di sapere cosa accade piuttosto che
perché accade.
Grazie