ABSTRACT
OBJECTIVE: The aim of this study was to determine whether side-lying hip abduction exercise while applying manual pelvic fixation is more effective than hip abduction without manual pelvic fixation for promoting deep trunk muscle activity. DESIGN: This is a cross-sectional study comparing deep trunk muscle activation between hip abduction exercise without and with manual pelvic fixation in ten participants. Muscle activation was measured using fine-wire and surface electromyography. RESULTS: Hip abduction with manual pelvic fixation was found to result in significantly more recruitment of all studied deep trunk muscles except the ipsilateral obliquus externus compared with hip abduction without manual pelvic fixation (P < 0.05). The greatest increased activation was seen in the ipsilateral deep and superficial multifidus. The increase in deep multifidus percentage of maximal voluntary contraction was greater than that of the rectus abdominis, the obliquus externus, the transversuus abdominis/obliquus internus, the lumbar erector spinae, the superficial multifidus, and the gluteus medius (P < 0.05). The superficial multifidus percentage of maximal voluntary contraction was significantly increased over that of the rectus abdominis and the obliquus externus (P < 0.05). Moderate correlation between deep and superficial multifidus activation was found (Pearson correlation coefficient, 0.537). CONCLUSIONS: Hip abduction training in the side-lying position while applying manual pelvic fixation seems to be more effective for recruiting deep trunk muscles for dynamic lumbar spinal stabilization.
