Gender Differences and the Impact of Fatigue on the Star Excursion Balance Test

Abstract

INTRODUCTION: The gluteus medius is an important muscle, which plays a major role in stabilizing the hip during unilateral stance activities, such as dynamic balance. Although many factors decrease neuromuscular control, one critical factor is fatigue. Men and women exhibit many physiological differences along with different kinematic movement patterns during sport specific activity, which combined with fatigue could result in certain predispositions for injury. PURPOSE: The objective of this study was to determine if there are gender differences in dynamic balance following fatigue of the hip musculature. METHODS: Recreational male (n = 20; age = 21.50 ± 2.31 years) and female (n = 20; age = 21.15 ± 2.58 years) athletes were examined. Dynamic balance was measured using the Star Excursion Balance Test (SEBT) in all 8 reach directions. All subjects reported to three separate testing sessions. During the first session, baseline SEBT and strength testing was collected. For the last two sessions, subjects were divided into groups; experimental and control. Experimental subjects (males = 10; females = 10) completed separate hip abduction and external rotation fatiguing exercises, followed by the SEBT. Fatigue was assessed with a handheld dynamometer at a 43% decrease in peak force compared to baseline measurements. Control subjects (males, n=10; females, n=10) rested during the second and third sessions, before performing the SEBT. A repeated measures ANOVA was used to analyze group by time by gender. RESULTS: No significant group by time by gender difference (p = 0.217) was seen for any reach distance. A significant main effect was found between gender (p=0.001). Males reached further than females regardless of group in the posterior lateral direction (p < 0.000), posterior direction (p < 0.000), posterior medial direction (p < 0.000), and the medial direction (p = 0.027). CONCLUSIONS: Isolated hip muscle fatigue does not impact reach differently in fatigued or non-fatigued males and females. However, men demonstrated further reach differences than women, regardless of fatigue. Men may have greater activation of hip musculature during dynamic balance, allowing them to reach further.