title: Activation of the gluteus medius according to load during horizontal hip abduction in a one-leg stance.
abstract: [Purpose] This study researched the influences of different loads on muscle activity of the posterior fibers of the gluteus medius in a one-leg standing position. [Subjects] Twenty-four healthy adult men participated in this study. [Methods] All participants performed the one-leg standing position under four conditions: the standard no-load condition, in which the non-weight-bearing leg was lifted and kept parallel to the back and then pelvic or lumbar rotation was performed without thorax rotation, and the 0 kg, 1 kg, and 3 kg load conditions, in which horizontal shoulder abduction was performed with a load of 0 kg, 1 kg, or 3 kg added to the hand. The electromyographic activity of the posterior fibers of the gluteus medius was measured using a wireless surface electromyography under all conditions. The electromyographic activity of each muscle under the four conditions during the one-leg stance was analyzed using one-way analysis of variance. [Results] The electromyographic activity of the posterior fiber of the gluteus medius was significantly increased under the 3 kg load condition compared with the no-load, 0 kg load, and 1 kg load conditions. [Conclusion] These findings indicated that muscle activation is affected by increases in load in the one-leg standing position. The load on the upper extremity influences the muscle activity of the contralateral lower extremity.
authors.affiliation: Department of Physical Therapy, Graduate School of Clinical Pharmacy and Health, Kyungsung University, Republic of Korea.
authors.forename: Jae-Woong
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Physical Therapy, Graduate School of Clinical Pharmacy and Health, Kyungsung University, Republic of Korea.
authors.forename: Yeong-Ju
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Physical Therapy, College of Science, Kyungsung University, Republic of Korea.
authors.forename: Hyun-Mo
authors.initials: HM
authors.lastname: Koo
keywords: Horizontal hip abduction; Load; Posterior fibers of the gluteus medius