Abstract:
It’s well-known that muscle fatigue is a key factor to deteriorate postural stability. In addition to, hyperthermia is enhancing the effect of muscle fatigue when exercise performed in hot environment compared with thermoneutral environment. Objective: To study the effect of exercise-induced fatigue on the dynamic postural stability in hot environment compared with thermoneutral environment and estimate the relative contributions of central and peripheral factors development of muscle fatigue. Method: twenty three-active male performed exercise-induced fatigue by 20-minute cycling exercise both in hot environment (31-33 ͦ C 60% relative humidity) and thermoneutral environment (23-25 ͦ C 50% relative humidity). Postural stability was measured by Dynamic postural stability index (DPSI) Integrated electromyography/compound muscle action potential (IEMG/CMAP) method was used to estimate the relative contributions of central and peripheral factors development of muscle fatigue. Results: DPSI after exercise-induced fatigue in hot environment (0.99 ± 0.15) was significantly (P < 0.05) higher than in thermoneutral environment (0.48 ± 0.10 ) For the IEMG/CMAP values, the (iEMG) signal after exercise-induced fatigue significantly decrease compared with before exercise, while the CMAP amplitude was unchanged. Conclusion: Effect of exercise-induced fatigue in hot environment had worse postural stability than in thermoneutral environment and the contribution factors relate to changes in central nervous system (CNS) which involve to central fatigue.
