BACKGROUND & OBJECTIVE
Patellefemoral (PF) pain is a debilitating injury for many recreational athletes. It is thought that excessive PF joint stress may be one the underlying causes of PF knee pain. 17% of knee-related orthopedic visits result in a diagnosis of PF pain syndrome (PFPS). The purpose of this study was to examine the effect of heel lifts on variables relating to PFPS: PF joint stress, PF stress impulse, quadriceps force, step length, cadence, and other kinematic and spatiotemporal variables.
Sixteen healthy active females (avg. age 20-23) completed five running trials (20 meters) in a controlled setting with and without 11mm heel lifts (controlled & randomized). All participants were experienced and healthy recreational runners (>10 miles per week for 5 years) with a rear foot striking pattern. Running speed was 7.7mph (12.4km/h) +-2.5%. All participants wore the same model new balance shoe. 3D data kinematic data (joint angles) were collected via a 15-camera and anatomical reflection suit system. Kinetic and kinematic data were collected and used in combination with a runway force plate in order to measure and estimate various muscle and joint forces.
When running with heel lifts, peak PF joint stress and PF stress impulse were reduced by 4.2% and 9.3%, respectively. Dorsiflexion at initial contact (IC) was reduced 28% with heel lifts. Initial center of pressure (COP) was shifted 9.1% anteriorly