LAUSR

BACKGROUND Side-lying hip abduction exercise could be beneficial to improve the neuromuscular control of the hip abductor; however, there has been limited information available to determine the exercise load during the exercise. OBJECTIVE This study aimed to demonstrate the effects of using external loads on the hip abductor muscles during side-lying hip abduction exercises in females with gluteus medius (GM) weakness. METHODS This study enrolled 24 females with weakness in the GM. Electromyographic (EMG) data of the quadratus lumborum (QL) and GM muscles were recorded during the exercise under three load conditions: no-load, external load-1 (3% of body weight), and external load-2 (5% of body weight). RESULTS During the exercise, the EMG activities of the QL were significantly different under all three conditions (p< 0.05), with greater activity observed in the external load-2 condition (92.05 ± 65.93% maximal voluntary isometric contraction [MVIC]) as compared to the others, and in the external load-1 condition (82.47 ± 57.36% MVIC) as compared to the no-load condition (48.94 ± 45.09% MVIC). Furthermore, the GM/QL ratios showed significant differences between no-load (1.78 ± 1.47) and external load-1 conditions (0.93 ± 0.60), and between no-load and external load-2 (0.85 ± 0.45) conditions (p< 0.05). CONCLUSION These findings suggest that greater load could be a factor to increase the QL activity during the exercise in females with weakened GM.