Relation of anterior pelvic tilt during running to clinical and kinematic measures of hip extension

Background-Limited hip extension flexibility due to tight hip flexor muscul ature or anterior hip capsular and Ligamentous structures is a possible cau se of increased anterior tilt of the pelvis during running. However, to dat e, research exploring this relation, as well as the kinematic relation betw een anterior tilt of the pelvis and peak hip extension range of motion duri ng running, is not available. Objective-To assess the relation of anterior pelvic tilt during running to peak hip extension range of motion measured during running and hip extensio n flexibility measured clinically. Methods-Hip extension flexibility was assessed using the Thomas test, and t he three dimensional kinematic motion of the pelvis and hips were recorded using a VICON motion analysis system with 14 elite athletes running on a tr eadmill at 20 km/h. Results-Anterior pelvic tilt displayed a significant (p<0.01) correlation w ith peak hip extension range of motion during running. Anterior pelvic tilt tended to be increased in runners who displayed reduced absolute peak hip extension range of motion during terminal stance. No significant correlatio n was shown for hip extension flexibility with either anterior pelvic tilt or peak hip extension range of motion during running. Conclusions-The outcomes of this study indicate that anterior pelvic tilt a nd hip extension are coordinated movements during running. Static hip exten sion flexibility measured using the modified Thomas test does not appear to be reflective of these dynamic movements.