Performance de l`extrême

11/5/2012
Performance de l’extrême
Prof. Grégoire Millet
1
Extrêmes ?
2
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11/5/2012
• Nowadays, mountain and trail running become more
and more popular
• Information about metabolic and neuromuscular
consequences had been collected on trails of a
duration of less than 50 h (ex. UTMB)
– No sleep deprivation
– No measurement during the competition
– No control group
3
Characteristics of the race
•
•
•
•
•
340 km
24’000 m D+ / D150 h
Only one stage
The winner: 75h 56min and only 3h sleep…
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11/5/2012
Non‐Stop Ultratrail
• Section 1
Courmayeur – Valgrisenche 49 km 3996 D+
• Section 2
Valgrisenche – Cogne 56 km 4141 D+
• Section 3
Cogne – Donnas 44 km 3348 D+ 25 passes > 2000 m
• Section 4
Donnas – Gressoney St Jean 53 km 4107 D+
• Section 5
Gressoney St Jean – Valtournenche 39 km 2601 D+
• Section 6
Valtournenche – Ollomont 44 km 2702 D+
ALT Max : 3300 m
ALT Min : 320 m
• Section 7
Ollomont – Courmayeur 48 km 2880 D+
5
Experimental design
• Start: n=417
• Finishers: n=301 (63%)
• Mean time: 131.1 ± 16.0 hours
(75.0/149.9)
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General fatigue
Muscular fatigue
Sleep deprivation
Inflammatory responses
Hallucinations
Traumatology
Postural control
Oedema
Muscle damage
Dehydration
Body composition
Mechanical alterations
Cardiac Fatigue
7
Method and study design
• Two different groups: runners (n=25) and control
(n=8)
• Three measurement points:
1. Before (pre-): n=25
2. During (mid-): n=15
3. After (post-): n=15
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11/5/2012
EXPERIMENTATIONS
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Measurements
Visual Analogic Scale :
‐ General fatigue
‐ Pain of foot and ankle
‐ Pain of Knee/thigh and pelvis
‐ Gastro intestinal disorders
Pain Pressure Threshold
‐ Quadriceps
‐ Triceps surae
‐ Tibialis anterior
Circumference
‐Thigh
‐Calf
Biomechanics of running
10
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11/5/2012
Measurements
Bio‐impedancemetry
Cognitive tests
Blood test
Neuromuscular tests:
‐ Knee extensors
‐ Plantar flexors
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Subjects
• Characteristics of the subjects:
Group
Weight
[kg]
Age [years]
Height
[cm]
Sleep at
mid [h]
Sleep at
post [h]
Runners
45.4 ± 10.3
69.8 ± 5.9
173.6 ± 5.5
1.2 ± 1.6
8.6 ± 5.2
Control
29.3 ± 8.1 #
70.9 ± 9.3
174.1 ± 5.6
1.2 ± 1.8
12.3 ± 5.4
#: p < 0.001 for differences between Runners and Controls
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11/5/2012
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Vitesse de course
% Vitesse équivalent plat moyenne
160%
150%
140%
130%
120%
D1
##
110%
###
D5
***
100%
D10
90%
###
80%
###
##
***
UTMB
70%
- 14 %
- 32 %
60%
RS1
RS2 14
RS3
RS4
TdG Mid
RS5
RS6
RS7
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11/5/2012
Gestion de l’allure
• Stratégie de course compétitive
haute intensité d’effort
peu de réserves

D1
• Stratégie de course de finisseur
allure plus prudente
épargne d’énergie

D5
• Allure réglée en prévision de
la ligne d’arrivée
 stratégie de téléo-anticipation
15
Fatigue
VAS‐General‐Fatigue
9
**
8
7
*
6
5
Runners
4
Control
3
2
1
0
Pre
Mid
Post
16
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11/5/2012
Pain
VAS‐Pain‐foot‐ankle
12
**
10
Foot /Ankle
**
8
6
Coureurs
Controle
4
2
0
Pre
Mid
Post
‐2
17
Pain
VAS‐Pain‐Knee‐Thigh‐Hip
8
**
7
*
6
5
4
Runners
3
Control
Knee /Thigh
2
1
0
Pre
Mid
Post
‐1
18
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11/5/2012
Pain Pressure Threshold
PPT‐TA
160
140
120
100
80
Runners
Control
60
40
Tibialis Anterior
20
0
Pre
Mid
Post
No change also in PPT for Gastrocnemius and Vastus lateralis.
No DOMS ? Desensibilization of nociceptive afferents ?
19
Neuromuscular function
• Assessment of the neuromuscular function alterations of the knee
extensors and plantar flexors induced by the “Tor des Géants”
• Plateau of fatigue suggested by Millet et al. (2004, 2011)
?
Strength diminution in
quadriceps (%)
Millet & Lepers Sports Med 2004
0
6
12
18
24
Running time (h)
30
36
150
20
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11/5/2012
2. Electrically
1.
Maximum voluntary
evoked torque
contraction (MVC)
- Doublets
- Single twitch
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MVC - KE
Knee extensor maximal torque [N]
450
***
400
350
CO
TOR
300
250
**
200
*
Decrease observed in control group confirm that
Pre
Mid
sleep
deprivation
inducesPost a diminution of
voluntary
strength
(Bulbulian
et oral,
*P<0.05; **P<0.01;
***P<0.001 for
differences between
measures in TOR
CO 1996)
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11/5/2012
MVC - PF
*P<0.05; ***P<0.001 for differences between measures in TOR or CO
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Potentiated doublet and twitch - KE
**P<0.01 between measures in TOR; # P<0.05 between groups
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11/5/2012
Potentiated doublet and twitch - PF
*P<0.05 for differences between measures in TOR or CO
25
Potentiated doublet and twitch
• The results show the presence of peripheral fatigue for the
runners  confirmed in precedent studies (Millet et al. 2011)
• Peripheral fatigue apparent only during the second part of the
race
• Explained by a combination of sleep deprivation and fatigue
induced by the prolonged exercise in TOR
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11/5/2012
KE Strength loss
Comparison of different exercises
100
100
MVC Knee extensor (%)
90
-16%
80
70
-40%
60
24 h
50
-35%
39 h
43 h
-29%
122 h
40
30
20
10
0
PRE
24h
UTMB
TDG
TDG Mid
• For the same km and D+/D- the decrease in MVC is
LOWER can be explained by the “pacing” (Tucker,
2009)
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-2%
24H
-10%
-35%
-40%
-3%
-14%
-30%
-39%
(Millet GY et al. 2011)
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11/5/2012
Peak Twitch quadriceps (N)
170
Peak Twitch triceps sural (Nm)
180
26
-4%
160
150
-22%
140
130
120
PRE
POST
J+2
J+5
J+9
J+16
+18%
24
22
20
18
-24%
16
14
PRE
POST
J+2
J+5
J+9
J+16
(Millet GY et al. 2011)
Comparison of different exercises
100
100

which -16%
tend
to
a
diminution
of
-29%
43instead
h
-35%
122 h
reaching
a
plateau
of
39 h
fatigue during long-distance
runs (Millet et al. 2011)
MVC Knee extensor (%)
90
80
70
-40%
60
24 h
50
40
30
Strength diminution in
quadriceps (%)
20
Millet & Lepers
Sports Med 2004
10
0
PRE
24h
UTMB
TDG
TDG Mid
• At the end, the strength loss tended to be smaller than in
previews exercises of shorter duration
0
6
12
18
24
30
36
150 h
Running time (h)
30
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11/5/2012
Oedema
Inflammation – Muscle damage
Pre
Post
TOR
CO
Creatine Kinase (UI · L-1)
112 ± 33
122 ± 41
3719 ± 3045***
148 ± 33###
TOR
CO
Lactate Dehydrogenase (UI · L-1)
340 ± 51
345 ± 65
1145 ± 511***
312 ± 35###
TOR
CO
C-Reactive Protein (mg · L-1)
0.31 ± 0.32
1.05 ± 1.04
13.11 ± 7.50***
0.65 ± 0.60##
TOR
CO
Creatinine (µmol · L-1)
0.94 ± 0.12
0.98 ± 0.18
0.95 ± 0.15
1.01 ± 0.17
TOR
CO
Myoglobin (µg · L-1)
25.6
26.1
449.3***
32.3
TOR
CO
Total Protein (g · L-1)
72.7
72.4
64.9***
73.1
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11/5/2012
Muscle damage - Inflammation
Muscle damage markers are 2.3 fold lower than on UTMB
CK increased by 3100% in TOR. However, the post-race level of CK in TOR
was much lower than on UTMB (3700 vs. 13600 UI.L-1).
This relative muscle “preservation” is also illustrated by the increase in
myoglobin concentration (+ 1734%) much lower than on UTMB (+ 4375%).
Lower pace during the second part - Walking
Inflammation markers are 2 fold higher than on UTMB
C-RP increased by 4300% in TOR. This rise was twice higher than in UTMB
(2240%), which indicates a greater inflammation in TdG, certainly due to the
longer event duration.
Circumference Calf
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Circumference Thigh
Fluid Volumes
**
***
• Increase in Body water and in extra-cellular Water
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11/5/2012
Relationship Fluid shift – Strength loss
R = - 0.74
P = 0.006
• Oedema reaction influences the strength loss
Relationship Fluid shift – Strength loss
R = - 0.69
P = 0.01
• Oedema reaction decreases the Excitation-Contraction coupling
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11/5/2012
Running mechanical alterations
Mechanical Alterations
*
*
6.9
± 12.6%

6.7
± 10.1%

• Increase in step frequency from pre- to mid- … then unchanged
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11/5/2012
Mechanical Alterations
**
*
-18.6
± 19.0%

-15.0
± 16.3%


-20.2
± 22.5%
-21.2
± 23.9%
***
***
• By decreasing the aerial time from pre- to mid- .. Then unchanged
Mechanical Alterations


-10.9
± 20.2%
-11.7
± 18.2%
*
*
• By minimizing the vertical oscillations.
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11/5/2012
Mechanical Alterations
-8.4
± 7.5%
-7.3
± 8.1%
***
***
• Strategy aiming to minimize the loads.
Mechanical Alterations
-
Higher step frequency by reducing their aerial time.
Lower vertical GRF
Reduced vertical oscillation COM
Higher vertical stiffness
‘‘smoother’’ and ‘‘safer’’ running style.
Strategy aiming to minimize the loads.
Lower impact, especially during the braking phase.
Observed already at mid-race.
Anticipatory protective strategy for minimizing the muscles-joints
damages
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11/5/2012
• In conclusion, it seems that the performance on this
type of event taking place over several days (80150 h) is strongly influenced by the race pace and
the management of sleep.
• Beyond the influence of the exercise duration, on
ultra distance trails, the strength loss is probably
related to other factors as inflammation or pain in
muscles and joints.
Impossible d’afficher l’image.
45
• Ultra-endurance studies allow us to better understand the time
course of degeneration/regeneration of some lower leg tissues
such as knee joint cartilage, to differentiate running-induced from
age-induced pathologies (for example, retropatelar arthritis) and
finally to assess the interindividual susceptibility to injuries.
• Moreover, it provides new information about the complex
interplay between cerebral adaptations/alterations and hormonal
influences resulting from endurance exercise and provide data on
the dose-response relationship between exercise and brain
structure/function.
• Overall, its represents a unique attempt to investigate the limits
of the adaptive response of human bodies and the optimal
coping strategies
Millet and Millet BMC Medicine 2012.
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11/5/2012
Kenny Guex
Francis Degache
Jonas Saugy
Lukas Oehen
Pietro Trabucchi
Federico Schena
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g2011-2-short.mp4
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