Correlation between Gluteus Maximus Strength and Pelvic Rotation Angle during Prone Hip Extension

Background: Active prone hip extension is an exercise commonly used in physical therapy for patients with hip or trunk dysfunction. Insufficient trunk muscle activation or gluteus maximus (GM) activity leads to lumbopelvic rotation during active prone hip extension. However, there is still a lack of research on whether GM strength or GM strength asymmetry causes pelvic rotation. Purpose: The current study aimed to investigate the relation of GM weakness to pelvic rotation during active prone hip extension in healthy individuals, specifically by examining the correlation between GM strength and pelvic rotation angle, as well as between GM strength asymmetry and difference in the pelvic rotation angles on the left and right sides. Study design: Cross-sectional study Methods: This analysis included 35 healthy male participants. Bilateral GM strength was measured using the Smart KEMA tension sensor. The pelvic rotation angle on the right and left legs was measured with a smart phone-based measurement tool during prone hip extension. The significance of the correlations between GM strength and pelvic rotation angle and between GM strength asymmetry and difference in pelvic rotation angles during prone hip extension was assessed using Pearson correlation coefficients. Results: There was a very large significant negative correlation between GM strength and pelvic rotation angle (r=–0.807) and a very large significant positive correlation between GM strength asymmetry and difference in pelvic rotation angles (r=0.825) during prone hip extension. Conclusions: GM strength and GM strength asymmetry influence pelvic rotation during hip extension movement.