The Effect of Isometric Hip External Rotation on Lower Extremity Muscles Activities During Pelvic Drop With Different Positions of the Hip Rotation in Subjects With and Without Genu Valgum: Controlled Laboratory Study

Background: Gluteus medius muscle (Gmed) dysfunction has been confirmed as a functional defect in subjects with Genu Valgum Deformity (GVD). In relation to these subjects, increase Gmed activity without synergist muscles dominance is considered as part of a specialized exercise program. Methods: : A total of thirty female recreational athletes with (n=15) and without (n=15) GVD participated in this study. Surface electromyography measured Gmed, tensor fascia latae (TFL), and quadratus lumborum (QL) muscles activity when subjects performed pelvic drop (PD) in three different positions of hip rotations with and without applied isometric hip external rotation force. Results: : There were differences in muscle activity between GVD and healthy subjects. The Gmed/TFL and Gmed/QL muscles activity ratio altered when placing the hip in different rotation positions and applying isometric load. Conclusions: : The lower extremity muscles activity is affected by GVD, and changing the positions of the hip rotation in the PD task can be associated with altered muscle activity in both GVD and healthy Groups. However, applying isometric hip external rotation during PD can be suggested as an effective intervention to increase Gmed activity.