Comparison of Gluteus Maximus and Biceps Femoris Muscle Activity and Activity Ratio during Prone Hip Extension with and without External Fixation in Healthy Subjects

Background: The gluteus maximus (GM) is important for functional movements, including hip extension and stabilization. However, few studies have been conducted on the effect of external fixation on GM muscle activity during prone hip extension exercise (PHE). Purpose: The study aims to investigate the effect of PHE with and without external fixation on GM muscle activity and GM/biceps femoris (BF) activity ratio during PHE. Study design: Cross-sectional design Methods: A total of 15 healthy male participated. Subjects were asked to perform PHE in two external fixation conditions (NONE: no fixation, FP: fixation on pelvic). During PHE, both Multifidus (MF), GM, and BF muscle activities were investigated by an Electromyographic device (EMG). Data were analyzed using SPSS software and compared using a paired t-test. The level of statistical significance was at α=0.05. Results: There were significant differences in GM muscle activity and GM/BF activity ratio with and without external fixation. GM muscle activity and GM/BF activity ratio were significantly increased in the FP condition compared to the NONE condition (p<0.01). Conclusions: It is recommended to perform the PHE with pelvic fixation to improve GM muscle activity and GM/BF muscle activity.