Mayer et al. (2002) investigated the effect of hip rotation angle on gluteus maximus EMG amplitude during 45 - degree back extensions. (strengthandconditioningresearch.com)
Several researchers have explored how hip internal - external rotation angle alters gluteus medius EMG activity during performance of the side - lying hip abduction exercise, by altering foot position (Philippon et al. 2011; McBeth et al. 2012; Lee et al. 2013a; Lee et al. 2014). (strengthandconditioningresearch.com)