Variations in Gluteus Medius Activity During Clam Exercise: Differences Due to Hip Flexion Angle During Exercise and Maximum Passive Internal Rotation Range.

OBJECTIVE: To assess differences in the activity of each gluteus-medius segment in response to variations in the maximum passive hip internal-rotation range and across ranges of hip flexion angle during clam exercises. DESIGN: Cross-sectional study. METHODS: The participants were healthy women. The maximum passive range of hip internal rotation was measured in prone with the hip in a neutral position and the knee flexed to 90°. Based on these values, participants were classified into 2 groups (the excessive-range group and the normal-range group). Differences in the activity of 3 gluteus-medius segments (anterior, middle, and posterior) during the clam exercise, performed at hip flexion angles of 30°, 45°, and 60°, were compared between groups. Analysis of variance for a split-plot factorial design was used to assess statistical differences (P = .05). RESULTS: Activity in the posterior gluteus-medius segment was significantly higher when the hip flexion angle was 60° (P = .042; 95% confidence interval [CI]: 0.10, 6.4; effect size, 0.32) or 45° (P = .035; 95% CI: 0.1, 4.2; effect size, 0.20) than when it was 30° during clam exercises. CONCLUSION: Deeper hip flexion angles during the clam exercise were associated with increased posterior gluteus-medius activity, regardless of individual differences in hip internal rotation range. JOSPT Open 2026;4(2):196-203. Epub 8 January 2026. doi:10.2519/josptopen.2026.0178.