Pelvifemoral rhythm during unilateral hip flexion in standing.

Objective: To quantify pelvifemoral rhythm during unilateral hip flexion in standing subjects, under different degrees of resistance.

Design: Descriptive and correlational.

Background: Pelvic rotation contributes to the change in hip flexion angle while individuals are supine. Degree of contribution in standing has not been described.

Methods: Pelvic and femoral motions, relative to vertical, were documented while 14 subjects performed three trials of standing unilateral hip flexion, both with and without a 4.53 kg ankle weight. Pelvic and thigh segments were marked with reflective spheres, and motion was captured by video analysis.

Results: Pelvic rotation contributed 18.1% of the change in hip flexion angle. Pelvic rotation occurred throughout the movement. Neither presence of external resistance nor direction of movement significantly changed this contribution.

Conclusions: A strong relationship exists between pelvic rotation and hip flexion in standing subjects.

Relevance: Hip flexion, while standing, is a common element of many functional activities. Knowledge of the pelvic contribution increases our understanding of hip and lumbar spine motion during standing activities.