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Effect of exercise-induced fatigue is considered to deteriorate the dynamic postural stability which is important for injury prevention. This effect was more pronounced when exercise performed in hot than thermoneutral environment. However, there is lack of evidence regarding the relationship between the effects of fatigue on dynamic postural stability in hot environment.
Purpose The purpose of this study was to investigate the effect of exercise-induced fatigue on the dynamic postural stability in hot environment compared with thermoneutral environment and differentiate the relative contributions of central and peripheral factors to the exercise-induced fatigue.
Methods The design of this study was randomized crossover trial. Twenty-three healthy males were divided into two groups to perform exercise-induced fatigue both in hot environment (31-33 ͦ C 60% relative humidity) and thermoneutral environment (23-25 ͦ C, 50% relative humidity). Dynamic postural stability index (DPSI) scores were identified by dynamic postural stability scores. In addition, the contributions of muscle fatigue were examined by comparing the change in integrated electromyography (iEMG) and Compound muscle action potential (CMAP) in lateral gastrocnemius muscle before and after exercise-induced fatigue.
Results The result showed that DPSI scores in hot environment (0.99 ± 0.15) was significantly (P < 0.05) higher than in thermoneutral environment (0.48 ± 0.10). Exercise-induced fatigue in hot environment had worse postural stability than in thermoneutral environment. This study found that iEMG of lateral gastrocnemius muscle significantly lower after exercise but there were no significant difference in CMAP in both groups.
Conclusion Exercise-induced fatigue in hot environment elicit greater negative effect on the dynamic postural stability than in thermoneutral environment. In addition, the contribution factors to muscle fatigue possibly related with central-fatigue component.
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