Isokinetic assessment of patellofemoral pain syndrome: A prospective study in female recruits

Abstract

Objective: To investigate prospectively the influence of muscular parameters on the development of the patellofemoral pain syndrome (PFPS) in women during a basic military training. Methods: Before the military training, 62 healthy female recruits, aged 18-34 years, without a history of PFPS, underwent an isokinetic test ( concentric contractions of knee flexors and extensors at 60 degrees/s and 240 degrees/s, eccentric contractions at 30 degrees/s). They also completed a questionnaire and performed a single-leg horizontal hop test. After basic military training, they underwent a clinical evaluation to assess PFPS. Independent t-tests and chi-square tests were used to evaluate whether any significant difference existed prior to the development of PFPS between females with and without PFPS. Results: The incidence of PFPS was 42%. Significantly lower peak torque of the extensors at 60 degrees/s and 240 degrees/s were observed in females with PFPS compared to the control group. The relative peak extensor torque per body weight and BMI, the ratio peak torque flexors/extensors and the sports participation were also significantly lower in the PFPS group. Conclusions: Decreased quadriceps strength and insufficient sports participations seem to be risk factors for the development of PFPS. Consequently, strengthening of quadriceps seems an important parameter in the treatment and prevention of PFPS.