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.
Damien Moore, Tania Pizzari, Jodie McClelland and Adam I. Semciw
Damien Moore, Adam I. Semciw, Jodie McClelland, Henry Wajswelner and Tania Pizzari
Context: The gluteus minimus (GMin) muscle consists of 2 uniquely oriented segments that have potential for independent function and have different responses to pathology and aging. For healthy young adults, it is unknown that which rehabilitation exercises specifically target the individual segments. Objective: To quantify segmental GMin activity for 6 common lower-limb rehabilitation exercises in healthy young adults and determine if significant differences exist in segmental activity levels between the exercises. Method: Six common lower-limb rehabilitation exercises were performed by 10 healthy young adults with fine-wire electromyography (EMG) electrodes inserted into the anterior and posterior segments of the GMin muscle. Main Outcome Measures: Electromyography signals were recorded, and median normalized exercise activity levels were reported and compared for each GMin segment across the 6 exercises. Results: High activity levels were generated in the anterior segment by the resisted hip abduction–extension exercise (51% maximum voluntary isometric contraction [MVIC]), whereas for the posterior segment, high activity levels were produced by the single-leg bridge (49% MVIC), the side-lie hip abduction (43% MVIC), the resisted hip abduction–extension exercise (43% MVIC), and the single-leg squat (40% MVIC). There were significant differences (P < .05) in the median electromyography activity levels for the anterior GMin segment but not for the posterior GMin segment across some of the exercises with large effect sizes. Conclusion: Targeted rehabilitation exercises graded by exercise intensity can be prescribed specifically for the anterior and posterior GMin segments to aid in restoration of hip function following injury or aging.