Sex and Speed Influence Frontal Plane Kinematics During Running

Abstract

Frontal plane mechanics, such as hip adduction angle and base of gait (BOG), have been implicated as causes for running-related injuries such as iliotibial band syndrome and patellofemoral pain. While modification of frontal plane variables may be a way to alter injury risk, the effect of speed and sex on frontal plane mechanics has not been investigated. Describing these effects may facilitate more appropriate prescription of gait retraining to reduce injury risk. PURPOSE: To determine the influence of sex and speed on frontal plane kinematics during running. METHODS: Whole body kinematics and ground reaction forces were collected for 99 NCAA Division I collegiate athletes (52 males) during treadmill running at 2.68, 3.35, and 4.47 m/s. Athletes were healthy at time of testing and had no history of lower extremity surgery. BOG at midstance (cm), hip adduction at initial contact (ADDIC, deg), peak hip adduction (ADDPK, deg), and peak contralateral pelvic drop (PELPK, deg) for the right limb were compared between sex and speed using 2-way repeated measures ANOVAs. RESULTS: A significant sex by speed interaction (p < 0.01) for BOG was observed. BOG decreased significantly (p < 0.01) with speed for both sexes. Females exhibited larger BOG than males at 3.35 and 4.47m/s (females: 0.6 ± 1.5 cm and -0.1 ± 1.5 cm, males: 0.2 ± 2.4 cm and -0.9 ± 2.5 cm for 3.35 and 4.47 m/s, respectively). No significant interactions (p ≥ .40) were observed for ADDIC, ADDPK, or PELPK. There was a significant speed main effect for ADDIC, ADDPK, and PELPK. ADDIC and ADDPK increased significantly with speed (p < 0.01). PELPK at 2.68m/s was significantly less than 3.35 and 4.47m/s (p < 0.01, mean difference = 0.5 deg). Females demonstrated greater ADDIC and ADDPK than males (p < 0.01, mean difference = 2.0 deg for both ADDIC and ADDPK). CONCLUSIONS: Females demonstrate a wider BOG than men at faster running speeds. Females also demonstrate greater hip adduction than men at the same running speed. As a result, both sex and speed must be considered when assessing frontal plane kinematic variables, particularly with regard to identifying excessive motion which may be related to injury.