Gluteal Muscle Activity During Weight-bearing and Non-Weight-bearing Exercise.

Authors:  MacAskill M, Wallace D, Durant T

Researchers have suggested that decreased strength of the gluteus medius (GMed) and the gluteus maximus (GMax) muscles contributes to the etiology of various orthopaedic pathologies of the knee. Currently, there is conflicting evidence regarding EMG activity of gluteal musculature during weight-bearing (WB) and non-weight bearing (NWB) exercise. Therefore, the purpose of this study was to examine the recruitment of posterior-lateral hip musculature during WB and NWB exercise. Surface EMG electrodes recorded the muscle activity of the GMax and GMed as subjects performed three sets of 10 repetitions of the following exercises: (1) Forward Step-up, (2) Side Step-up, (3) 10 repetition maximum (RM) side lying hip abduction and (4) 10 RM prone hip extension.  Performing a 10 RM side lying exercise recruited the GMed significantly greater than remaining exercises (Sidelying, 99.9±17% vs. Side Step-up, 61±20%; Forward Step-up, 62.7±18.2%; Prone, 38±22.2%)(p<0.05). The GMax demonstrated the greatest activity during prone hip extension (Prone, 100.7±14.5% vs. Forward Step-up, 28.7±18.7%; Side Step-up, 31±19.9%; Sideling, 38±23.3%)(p<0.05). The GMed demonstrated greater activity than the GMax during each exercise with the exception of the prone hip extension (p<0.05). These results suggest that performing a 10 RM NWB exercise results in greater muscle activity than a functional WB exercise without load in young, healthy individuals. In addition, forward and side step-ups fail to effectively recruit the GMax. The GMed was recruited to a higher extent during the stepping tasks which might be further augmented if the activity is performed with an additional external load.

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