Comparison of Hip Stabilization Muscle Use during Neutral Sit to Stand and Sit to Stand Involving Isometric Hip Abduction in Elderly Females

[Purpose] The purpose of this study was to compare the activation of the gluteus medius (Gmed), rectus femoris (RF), and biceps femoris (BF) muscles during neutral (N) sit to stand (STS) and STS involving hip abduction (ABD) in elderly females. [Subjects] We recruited 16 healthy elderly females with no pain in the knee joint or any other orthopedic problems of the lower limbs. [Methods] The activities of the dominant lower extremity muscles were measured using a wireless electromyography (EMG) system. Subjects then undertook a total of six STS trials: three for neutral STS and three for STS involving hip abduction. [Results] In the pre-TO phase, activation of the RF muscle was significantly increased during hip ABD. In the post-TO phase during hip ABD, Gmed muscle activation was significantly increased, and RF muscle activation was significantly decreased. [Conclusion] This study suggests that STS involving hip ABD is more effective in decreasing Gmed activation and reducing RF effort in elderly females.