The Cross-Over Influence of Unilateral Lower Limb Muscular Fatigue on Postural Control

Abstract

The purpose of this study was to examine the cross-over influence of lower limb fatigue on postural control. Young, healthy TCU students (N=20; ages 20.6 ± 1.0 years old; 10 males, 10 females) participated in the study. The study involved six single-legged balance tasks performed on a force plate andconducted before and after a fatiguing exercise that included four sets of one-minute single-legged squats on the dominant leg with 30 seconds of rest in between each set. Postural control data, medial-lateral (ML) and anterior-posterior (AP) sway, were collected on the force plate during the balance tasks:right leg eyes open, left leg eyes open, right leg eyes closed, left leg eyes closed, right leg on foam surface, and left leg on foam surface. Data were analyzed with the linear variable of standard deviation (SDML, SDAP) and the nonlinear variable of detrended fluctuation analysis (dfaML,dfaAP). The results lacked significant differences (p>0.05) for crossover fatigue effects on both the non-exercised and exercised legs, which exhibited similar levels of postural sway between pre-and post-fatigue balance tests. Results indicated some participants increased while some decreased postural sway post-fatigue exercise. In conclusion, the single-legged squat task may have lacked an appropriate level of duration or intensity to cause a significant effect of central fatigue on the nervous system. The findings underscore the need to better understand how a specific fatiguing task during unilateral rehabilitation may alter postural control.