The effect of fatigue in hip abductor muscles on balance in healthy young adults: a preliminary case series

BACKGROUND: The association of hip abductor muscle strength and postural control firmly established, however; the correlation of medial-lateral (M-L) sway, anterior-posterior (A-P) sway and center of pressure (COP) is still controversial. In this context, the aim of this study was to analyze whether the fatigue of hip abductor muscle has an effect postural control or not. METHODS: Seven healthy young adults (mean age 27.9) are voluntarily included this study. Participants followed a fatiguing protocol that involved hip-abduction exercise against the resistance performed by Cybex. The baseline and post fatigue measurements of single-leg static balance with CoP measurement by RSscan. RESULTS: After hip abductor muscle fatigue protocol, the mean M-L sway (P=0.046), A-P sway (P=0.028) and CoP values (P=0.043) increased significantly when compared to pre-fatigue measurements. CONCLUSIONS: This study showed that fatigue in hip abductor might increase the CoP on single leg balance in young adult healthy participants. the results of the current study also identified significant postural sway increase in sagittal plane when compared to frontal plane. Further robust studies, which have large sample sizes, need to evaluate the association the hip abductor muscle fatigue on postural stability.