Influence of Unilateral Muscle Fatigue in Knee and Ankle Joint on Balance and Gait in Healthy Adults

Abstract

Purpose: This study was to investigate the effects of unilateral muscle fatigue in knee and ankle joints on balance and gait in healthy adults. Methods: Exercise inducing muscle fatigue in the knee joint consisted of concentric and eccentric contraction of dominant knee exten sors in healthy adults by using the Leg Extension Rehap exercise machine (HUR, Finland). Exercise inducing muscle fatigue in the ankle joint was composed of voluntary contractions and forced contractions of the dominant plantar flexors in healthy adults. Exercises to in duce muscle fatigue in the knee and ankle joints were performed until the subject complained of fatigue or pain, the occurrence of mus cle fatigue was confirmed by electromyography. We measured static and dynamic balance using the Good Balance system and gait per formance by RS-scan. Results: Static and dynamic balance ability and spatial-temporal gait decreased significantly after muscle fatigue in knee and ankle joint. Conclusion: These results show that unilateral muscle fatigue of the lower extremities affected postural control and gait. Therefore, therapists and sport trainers should minimize the risks of fall and injuries related to unilateral muscle fatigue.