Effectiveness of static quadriceps stretching in individuals with patellofemoral joint pain

Objective: To determine if a 3-week static stretching program would increase quadriceps muscle flexibility in patellofemoral joint pain syndrome (PJPS) individuals. Design: Pretest/posttest control group design. Setting: Institutional based clinical rehabilitation setting. Participants: Participants (n = 83) were between the ages of 18 and 45 years of age with no history of surgery or trauma to the hip, knee, or lower leg region. Intervention: Participants were sorted into normal and PJPS groups via orthopaedic assessment of knee pain and function, and their quadriceps flexibility was evaluated. All subjects completed a 3-week static quadriceps stretching program. Flexibility, knee pain, and function were then reassessed. Main Outcome Measurements: Parametric and nonparametric tests were used to compare the groups' pre and poststretching knee pain, function, and quadriceps flexibility scores. Results: Prestretching anthropometric and physical activity data illustrated that the groups were homogenous, with severity of knee pain, joint dysfunction, and quadriceps flexibility being the prime differences. Following the stretching program, a significant improvement in flexibility was detected for both groups, and the PJPS group reported a significant decrease in knee pain and improved joint function. However, Pearson product-moment correlation coefficients indicated that changes in quadriceps flexibility were poorly correlated with changes in knee pain and function. Conclusion: This study confirms the effectiveness of a 3-week static stretching regimen for enhancing quadriceps flexibility and knee joint function, but fails to demonstrate a statistical relationship between quadriceps flexibility and the severity of knee pain and joint dysfunction in a PJPS population.