Comparison of the effects of external instruction exercises in combination with hip-knee strengthening on gait kinematics in patients with patellofemoral pain syndrome: a randomized clinical trial.

Aims and Background: Patellofemoral pain syndrome is one of the most common musculoskeletal disorders, and is related to biomechanical factors of the lower extremities. The purpose of this study was to compare the effect of hip and knee strengthening with internal instruction exercises on pain and dynamic knee valgus in patients with Patellofemoral pain syndrom. Materials and Methods: 50 men and women with Patellofemoral pain syndrom (18 to 45 years) participated in this study. Subjects were assigned to experimental (n = 25) and control (n = 25) groups. Evaluation of gait kinematics was conducted using two-dimensional video camera. Subjects in the control group received hip and knee strengthening exercises and in the experimental group performed hip and knee strengthening with external instruction exercise for six weeks. Independent and dependent T-tests were used for statistical analysis. Findings: The results of the statistical tests showed that addition of external focus instruction on hip and knee strengthening exercises affected the lower extremity kinematics of Patellofemoral pain syndrom subjects and significantly improved the lower extremity kinematics (p≤0. 05). Conclusion: Hip and knee strengthening with external instructions exercises seem to be more effective in improving gait kinematics than exercises that focus solely on strengthening the hip and knee muscles.