Gluteus Maximus and Hamstring Activation During Selected Weight-Bearing Resistance Exercises.

McCurdy, K, Walker, J, and Yuen, D. Gluteus maximus and hamstring activation during selected weight-bearing resistance exercises. J Strength Cond Res 32(3): 594-601, 2018-The purpose of this study was to compare the gluteus maximus (GM) and hamstring group (HG) electromyographic (EMG) activation levels among selected weight-bearing resistance exercises. Eighteen young adult females with previous resistance training experience completed the study. Strength was assessed on the bilateral squat (BS) (3 repetition maximum [RM]), modified single-leg squat (MSLS) (3RM), and stiff-leg deadlift (SLDL) (8RM) to determine an 8RM load for all lifts. Surface EMG was collected after 48 hours of rest using wireless Trigno IM Sensors using EMMA software (Delsys), which also collected and synchronized 3D hip and knee motion. A maximum voluntary isometric contraction was determined for the GM and HG to normalize the EMG data. During EMG data collection, 3 repetitions were completed using an 8RM load on all 3 exercises. Gluteus maximus EMG was significantly greater than HG EMG on the BS (40.3 vs. 24.4%, p < 0.001), MSLS (65.6 vs. 40.1 %, p < 0.012), and SLDL (40.5 vs. 29.9 %, p < 0.047). The MSLS produced significantly greater HG EMG (p = 0.001) compared with the SLDL, whereas the SLDL was significantly greater (p = 0.004) than the BS. The MSLS GM EMG was also significantly greater (p < 0.001) than the SLDL and BS, whereas no difference was found between the SLDL and BS. Comparing the activation of the 2 muscle groups in all exercises, the GM seems to be the primary muscle recruited whereas the MSLS seems to produce greater GM and HG activation. The data indicate that it would be most beneficial to include the MSLS during GM and HG training.