Influence of Musculo-Tendinous Stiffness of the Plantar Ankle Flexor Muscles upon Maximal Power Output on a Cycle Ergometre
Résumé
The importance of maximal voluntary torque (TMVC), maximal rate of torque development (MRTD) and musculo-tendinous stiffness of the triceps surae for maximal power output on a cycle ergometre (Pmax) was studied in 21 healthy subjects by studying the relationships between maximal cycling power related to body mass (Pmax BM-1) with TMVC, MRTD and different indices of musculo-tendinous stiffness of the ankle flexor. Pmax BM-1 was calculated from the data of an all-out force-velocity test on a Monark cycle ergometre. TMVC and MRTD were measured on a specific ankle ergometre. Musculo-tendinous stiffness was estimated by means of quick releases at 20, 40, 60 and 80% TMVC on the same ankle ergometre. Pmax BM-1 was significantly and positively correlated with MRTD related to body mass but the positive correlation between Pmax BM-1 and TMVC did not reach the significance level (0.05). Pmax BM-1 was significantly and positively correlated with the estimation of stiffness at 40% TMVC (S0.4), but not with stiffness at 20, 60 and 80% TMVC. The results of the present study suggest that maximal power output during cycling is significantly correlated with the level of musculo-tendinous stiffness which corresponds to torque range around peak torque at optimal pedal rate. However, the low coefficient of determination (r2 = 0.203) between Pmax BM-1 and S0.4 BM-1 suggested that Pmax BM-1 largely depended on other factors than the musculo-tendinous stiffness of the only plantar flexors.