The Biomechanics Characteristics Of Female Runners With Patellofemoral Pain Syndrome In Different Trunk Posture

Objective: The purpose of this study was to investigate the biomechanics characteristics of the runners with and without patellofemoral pain syndrome and the influence of trunk posture on these characteristics.Method: Thirty female recreational runners(15 PFPS group,15 control group)ran overground at a speed of 3.4m/s in self-selected trunk posture while PFPS ran in another two trunk posture conditions: flexed and extended.All participant was tested muscle strength and collected data of kinematics and ground reaction force.Results: Subjects with PFPS had increased peak hip flexion(P=0.002)and lower trunk flexion(P=0.033)angle.PFPS runners had increased peak hip flexion(P=0.000)and trunk flexion(P=0.000)angle,PFJCA(P=0.012)and lower peak hip internal rotation(P=0.003)angle,and PFJ stress(P=0.001)in trunk flexed posture.While the trunk flexion angle(P=0.004),PFJF(P=0.045)and PFJ stress(P=0.027)had increased in trunk extended condition.No significant difference was found from the rest data.Conclusion: There is no significate hip muscle strength deficit in female PFPS runners.Female PFPS runners have less hip flexion and trunk flexion angle during running.Runners with patellofemoral pain may use trunk lean forward strategy to lower PFJ stress.