Effect of different pelvic-drop exercises on hip muscles activity in patients with gluteus medius weakness

BACKGROUND: Pelvic-drop exercise (PD) is unilateral weight-bearing exercise that is frequently performed in rehabilitation sessions because its easy application can trigger moderate-to-high gluteus medius (Gmed) activity. Hip rotation has been applied to effectively facilitate Gmed activity during exercise. OBJECTIVE: To determine the effects of PD with three different hip rotations on Gmed, tensor fasciae latae (TFL), gluteus maximus (Gmax) activity, and Gmed:TFL activity ratio in patients with Gmed weakness. METHODS: Eighteen subjects with Gmed weakness participated. Subjects performed three different forms of PD with neutral hip, hip internal rotation, and hip external rotation position. Surface electromyography was performed to quantify the activity of Gmed, TFL, and Gmax. RESULTS: PD with hip internal rotation showed significantly greater Gmed activity than with neutral hip and hip external rotation (P= 0.005 and P= 0.007, respectively). TFL also showed significantly greater activity during PD with hip interna rotation than neutral hip (P= 0.002). There were no significant differences in Gmax activity (P= 0.095) and Gmed:TFL activity ratio (P= 0.254) among different forms of PD. CONCLUSIONS: PD with hip internal rotation is recommended to stimulate greater Gmed activity while preserving Gmed:TFL muscle activity ratio.