Performance de l extrême

Transcription

1 Performance de l extrême Prof. Grégoire Millet 1 Extrêmes? 2 1

2 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 m D+ / D- 150 h Only one stage The winner: 75h 56min and only 3h sleep 4 2

3 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+ 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+ Section 7 Ollomont Courmayeur 48 km 2880 D+ 25 passes > 2000 m ALT Max : 3300 m ALT Min : 320 m 5 Experimental design Start: n=417 Finishers: n=301 (63%) Mean time: ± 16.0 hours (75.0/149.9) 6 3

4 General fatigue Muscular fatigue Inflammatory responses Traumatology Sleep deprivation Hallucinations 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 8 4

5 EXPERIMENTATIONS 9 Visual Analogic Scale : General fatigue Pain of foot and ankle Pain of Knee/thigh and pelvis Gastro intestinal disorders Measurements Pain Pressure Threshold Quadriceps Triceps surae Tibialis anterior Circumference Thigh Calf Biomechanics of running 10 5

6 Measurements Bio impedancemetry Cognitive tests Blood test Neuromuscular tests: Knee extensors Plantar flexors 11 Subjects Characteristics of the subjects: Group Age [years] Weight [kg] Height [cm] Sleep at mid [h] Sleep at post [h] Runners 45.4 ± ± ± ± ± 5.2 Control 29.3 ± 8.1 # 70.9 ± ± ± ± 5.4 #: p < for differences between Runners and Controls 12 6

7 13 Vitesse de course 160% % Vitesse équivalent plat moyenne 150% 140% 130% 120% 110% 100% 90% 80% 70% ## *** ### UTMB ## - 14 % - 32 % ### ### *** D1 D5 D10 60% RS1 RS2 14 RS3 RS4 RS5 RS6 RS7 TdG Mid 7

8 Gestion de l allure Stratégie de course compétitive D1 haute intensité d effort peu de réserves Stratégie de course de finisseur D5 allure plus prudente épargne d énergie Allure réglée en prévision de la ligne d arrivée stratégie de téléo-anticipation 15 Fatigue 9 8 VAS General Fatigue ** 7 6 * Runners Control Pre Mid Post 16 8

9 Pain VAS Pain foot ankle ** ** Foot /Ankle 6 Coureurs 4 Controle Pre Mid Post 17 Pain * VAS Pain Knee Thigh Hip ** Runners Control Knee /Thigh Pre Mid Post 18 9

10 Pain Pressure Threshold 160 PPT TA Runners Control Tibialis Anterior 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 Running time (h) 150? 20 10

11 2. 1. Electrically Maximum voluntary evoked torque contraction (MVC) - Doublets - Single twitch 21 MVC - KE Knee extensor maximal torque [N] *** *P<0.05; **P<0.01; ***P<0.001 for differences between measures in TOR or CO CO TOR ** * Decrease observed in control group confirm that Pre Mid Post sleep deprivation induces a diminution of voluntary strength (Bulbulian et al, 1996) 22 11

12 MVC - PF *P<0.05; ***P<0.001 for differences between measures in TOR or CO 23 Potentiated doublet and twitch - KE **P<0.01 between measures in TOR; # P<0.05 between groups 24 12

13 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 26 13

14 KE Strength loss Comparison of different exercises MVC Knee extensor (%) % 24 h -35% 39 h -29% 122 h -16% 43 h 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) 27-10% -2% 24H -35% -40% -3% -14% -39% -30% (Millet GY et al. 2011) 14

15 Peak Twitch triceps sural (Nm) Peak Twitch quadriceps (N) % -22% PRE POST J+2 J+5 J+9 J % -24% PRE POST J+2 J+5 J+9 J+16 (Millet GY et al. 2011) Comparison of different exercises Strength diminution in quadriceps (%) MVC Knee extensor (%) % 24 h Millet & Lepers Sports Med 2004 PRE 24h UTMB TDG TDG Mid At the end, the strength loss tended to be smaller than in previews exercises of shorter duration Running time (h) which tend to a -16% diminution -29% 43 instead h of -35% reaching122 h a plateau of 39 h fatigue during long-distance runs (Millet et al. 2011) 150 h 30 15

16 Oedema Inflammation Muscle damage Pre Post Creatine Kinase (UI L -1 ) TOR 112 ± ± 3045*** CO 122 ± ± 33### Lactate Dehydrogenase (UI L -1 ) TOR 340 ± ± 511*** CO 345 ± ± 35### C-Reactive Protein (mg L -1 ) TOR 0.31 ± ± 7.50*** CO 1.05 ± ± 0.60## Creatinine (µmol L -1 ) TOR 0.94 ± ± 0.15 CO 0.98 ± ± 0.17 Myoglobin (µg L -1 ) TOR *** CO Total Protein (g L -1 ) TOR *** CO

17 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 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 17

18 Circumference Thigh Fluid Volumes ** *** Increase in Body water and in extra-cellular Water 18

19 Relationship Fluid shift Strength loss R = P = Oedema reaction influences the strength loss Relationship Fluid shift Strength loss R = P = 0.01 Oedema reaction decreases the Excitation-Contraction coupling 19

20 Running mechanical alterations Mechanical Alterations * * 6.9 ± 12.6% 6.7 ± 10.1% Increase in step frequency from pre- to mid- then unchanged 20

21 Mechanical Alterations ** * ± 19.0% ±23.9% ± 16.3% ±22.5% *** *** By decreasing the aerial time from pre- to mid-.. Then unchanged Mechanical Alterations ± 20.2% ± 18.2% * * By minimizing the vertical oscillations. 21

22 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 22

23 Impossible d afficher l image. 11/5/2012 In conclusion, it seems that the performance on this type of event taking place over several days ( 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. 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 46 Millet and Millet BMC Medicine

24 Kenny Guex Francis Degache Jonas Saugy Lukas Oehen Pietro Trabucchi Federico Schena 47 g short.mp4 24