Date of Paper/Work


Type of Paper/Work

Research Project

Degree Name

Doctor of Physical Therapy (DPT)


Physical Therapy

First Advisor

John S. Schmitt



Patellofemoral pain syndrome (PFPS) is a common form of knee pain occurring insidiously, and exacerbated by overuse activities. PFPS is common among athletes and adolescent females. Research suggests that hip weakness contributes to the development of PFPS. Similarly, biomechanical reasoning suggests a link between core endurance and PFPS. Few studies have explored these relationships in adolescent females. The purpose of this study was to investigate relationship between hip strength and core endurance in adolescent female athletes with PFPS in comparison to gender and sport matched controls.


Female runners age 13-17, 6 with PFPS and 17 without knee pain.


: A case control design was utilized. The Kujala Anterior Knee Pain Scale and multiple Visual Analog Pain Scales were administered prior to testing. Hip external rotation and abduction strength were measured using handheld dynamometers secured with straps. Strength measurements were normalized to body weight. The highest recorded measurement of two trials was utilized for data analysis. Core endurance was assessed with timed lateral planks.


Number Cruncher Statistical Software 8 was used. Descriptive statistics, t-tests, and Mann-Whitney U tests were utilized to analyze the data. Pearson correlation coefficients were used to assess the degree of relationship among strength, endurance, pain, and Kujala scores for the case group. Effect sizes were calculated for further analysis.


PFPS subjects generated 12% greater median hip abduction and 7% less median hip external rotation strength than controls. In contrast, PFPS subjects demonstrated 22% less median core endurance than the controls. Due to a small sample size, results were not statistically significant.


This pilot study indicates further research, with more subjects, is needed to investigate the relationship between hip strength, core endurance, and PFPS in adolescent females.


Our research suggests that hip and core muscular endurance, in addition to muscular strength should be evaluated in adolescent female runners presenting with PFPS.