Electromyographic analysis of gluteus medius subdivisions during hip abductor strengthening exercises

BACKGROUND: The gluteus medius (GM) which functions mainly in weight-bearing to stabilize the pelvis in a unilateral stance against gravity has been described as having several anatomic subdivisions. OBJECTIVE: The aim of this study was to compare the activation of the three GM subdivisions (anterior, medial, and posterior) during four weight bearing exercises. METHODS: This study investigated GM activation in 15 healthy adult males during four weight-bearing exercises; hip fire hydrant, standing forward bent-horizontal hip abduction (SFB-HHA), wall press and pelvic drop. Muscle activations in the three GM subdivisions were measured using electromyography (EMG) and compared using a repeated one-way ANOVA. RESULTS: All GM subdivisions showed higher activation during high position exercises (pelvic drop, SFB-HHA, wall press exercise) than during the low position exercise (hip fire hydrant). The anterior subdivision showed higher activity during pelvic drop exercise than during SFB-HHA and wall press exercises. Higher posterior subdivision activity was observed during SFBHHA compared to wall press and pelvic drop exercises, posterior subdivision activity was higher during wall press compared to pelvic drop. CONCLUSIONS: The results suggest that pelvic drop is the appropriate exercise to activate the anterior subdivision of the GM, whereas SFB-HHA is the best exercise to activate the posterior subdivision.