Research describing pelvifemoral rhythm: a systematic review.

[Purpose] This systematics review was undertaken to synthesize what is known regarding pelvifemoral rhythm, that is, the coordinated flexion of the thigh and posterior tilting of the pelvis during hip flexion (HF). [Methods] Three databases were searched. [Results] Nine relevant articles were identified via independent database searches and a hand search by the authors. The articles were consistent in showing that pelvifemoral rhythm underlies the HF motion under conditions as varied as passive unilateral flexion while supine and active bilateral flexion while hanging from a bar. Posterior pelvic tilting, which begins early during HF, contributes between 13.1% to 37.5% of total HF. Pelvic tilting and HF excursions are highly correlated (r=0.89 to 1.00). [Conclusions] Pelvifemoral rhythm is present to varying degrees during hip flexion under diverse conditions.