Gluteus medius activity during 3 variations of isometric single-leg stance

Context: Gluteus medius (GM) contraction during single-leg stance prevents the contralateral pelvis from "dropping," providing stability for lower extremity motion. Objective: To determine which combination of hip rotation and abduction exercise results in the greatest activity of the GM and whether the GM responds to increased loads in these exercises. Design and Settings: Repeated measures, laboratory. Subjects: 20 healthy volunteers. Interventions: Resistance (2.26 and 4.53 kg) was provided to 3 variations of a single-leg-stance exercise: hip abduction only, abduction-internal rotation (ABD-IR), and abduction-external rotation. Measurements: Muscle activity was recorded from the anterior and middle portions of the GM using surface electromyography. Results: ABD-IR produced the most activity in the anterior and middle sections of the GM muscle. The 4.53-kg load produced significantly more activity than the 2.26-kg load (P <.05). Conclusions: The GM is most active when performing abduction and internal rotation of the hip. This information could be used to develop GM-strengthening exercises.