Effects of Log-Rolling Position on Hip-Abductor Muscle Activation During Side-Lying Hip-Abduction Exercise in Participants With Gluteus Medius Weakness.

CONTEXT: Weakness of the gluteus medius and gluteus maximus is associated with a variety of musculoskeletal disorders. However, activation of synergistic muscles that are not targeted should be considered when prescribing side-lying hip-abduction (SHA) exercises. Log-rolling positions may affect hip-abductor activity during SHA. OBJECTIVE: To determine the effects of log-rolling positions on gluteus medius, gluteus maximus, and tensor fasciae latae activity during SHA in participants with gluteus medius weakness. DESIGN: Controlled laboratory study. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Twenty-one participants with gluteus medius weakness. INTERVENTION(S): Three types of SHA were performed: frontal-plane SHA in neutral position (SHA-neutral), frontal-plane SHA in anterior log-rolling position (SHA-anterior rolling), and frontal-plane SHA in posterior log-rolling position (SHA-posterior rolling). MAIN OUTCOME MEASURE(S): Surface electromyography was used to measure hip-abductor activity. One-way repeated-measures analysis of variance was calculated to assess the statistical significance of the muscle activity. RESULTS: The SHA-anterior rolling showed greater gluteus medius and gluteus maximus activation than the SHA-neutral (P = .003 and P < .001, respectively) and SHA-posterior rolling (P < .001 and P < .001, respectively). The SHA-neutral demonstrated greater gluteus medius and gluteus maximus activation than the SHA-posterior rolling (P < .001 and P = .001, respectively). The SHA-anterior rolling produced less tensor fasciae latae activation than the SHA-neutral (P < .001) and SHA-posterior rolling (P < .001). The SHA-neutral showed less tensor fasciae latae activation than the SHA-posterior rolling (P < .001). CONCLUSIONS: The SHA-anterior rolling may be an effective exercise for increasing activation of the gluteus medius and gluteus maximus while decreasing activation of the tensor fasciae latae in participants with gluteus medius weakness.