Sex differences in lower extremity coordinative variability during running

Abstract

BackgroundDifferences in coordinative variability have been previously reported between healthy and injured runners. Many running-related injuries have a sex bias, particularly patellofemoral pain (PFP), as female runners are approximately twice as likely to develop PFP compared to males. However, very little is currently known regarding sex differences in coordinative variability during running. Research QuestionAre there sex differences in continuous relative phase (CRP) variability for pelvis-thigh and thigh-shank couplings during the stance phase of running? MethodsPelvis, thigh, and shank segment kinematics were collected on 15 female and 15 male subjects during overground running at a self-selected easy pace (2.39–3.56 m/s) using a 10-camera 3D motion capture system. Continuous relative phase (CRP) variability was calculated between the pelvis-thigh and thigh-shank, and averaged during four distinct stance sub-phases. A mixed effects linear model compared CRP variability between sexes at each stance sub-phase. ResultsCompared to males, females displayed significantly lower pelvis-thigh CRP variability in the transverse plane during the loading response phase, and significantly lower thigh-shank CRP variability in the sagittal plane during the loading response and pre-swing phases. SignificanceLower coordinative variability in females during the loading response for two couplings may provide additional insight into the sex bias for developing certain running-related injuries. However, any injury implications from these results are speculative and should be interpreted with caution.