Context: Many different rehabilitation exercises have been recommended in the literature to target the gluteus medius (GMed) muscle based mainly on single-electrode, surface electromyography (EMG) measures. With the GMed consisting of 3 structurally and functionally independent segments, there is uncertainty on whether these exercises will target the individual segments effectively.
Objective: To measure individual GMed segmental activity during 6 common, lower-limb rehabilitation exercises in healthy young adults, and determine if there are significant differences between the exercises for each segment.
Method: With fine-wire EMG electrodes inserted into the anterior, middle, and posterior segments of the GMed muscle, 10 healthy young adults performed 6 common, lower-limb rehabilitation exercises.
Main outcome measures: Recorded EMG activity was normalized, then reported and compared with median activity for each of the GMed segments across the 6 exercises.
Results: For the anterior GMed segment, high activity was recorded for the single-leg squat (48% maximum voluntary isometric contraction [MVIC]), the single-leg bridge (44% MVIC), and the resisted hip abduction-extension exercise (41% MVIC). No exercises recorded high activity for the middle GMed segment, but for the posterior GMed segment very high activity was recorded by the resisted hip abduction-extension exercise (69% MVIC), and high activity was generated by the single-leg squat (48% MVIC) and side-lie hip abduction (43% MVIC). For each of the GMed segments, there were significant differences (P < .05) in the median EMG activity levels between some of the exercises and the side-lie clam with large effect sizes favoring these exercises over the side-lie clam.
Conclusions: Open-chain hip abduction and single-limb support exercises appear to be effective options for recruiting the individual GMed segments with selection dependent on individual requirements. However, the side-lie clam does not appear to be effective at recruiting the GMed segments, particularly the anterior and middle segments.
Keywords: EMG; exercise therapy; gluteal muscles; hip.