Introduction: Patellofemoral pain syndrome is one of the most prevalent problems in physically active people. The syndrome is a multifactorial disorder with different therapeutic approaches. Conservative treatment of the syndrome has been a crucial matter in different studies. Quadriceps muscle strengthening exercise is a recommended approach which is performed in forms of open and closed kinetic chain exercises. This study was designed to compare the efficacy of these exercises on this syndrome. Methods: Totally 30 women suffering from the syndrome aged 30-40 were randomly allocated into three groups: open, and closed kinetic chain exercises, and control group, as groups A, B, and C, respectively. Groups A and B participated in 28 sessions of exercises in a period of four weeks and group C did not do any exercise in this period. Before and after the period, pain and function of the participants were assessed using visual analog scale (VAS) and Kujala patellofemoral scale, respectively. Data were analyzed using independent t test, dependent t test, and univariate variance analysis, while significance of data was determined at P < 0.05. Results: The study indicated that open kinetic chain exercises (group A) for 4 weeks brought significant changes in relieving the pain along with improving the function (P = 0.001). Likewise, it was revealed a significant pain relief as well as function improvement in group B (P = 0.001). Comparing two groups illustrated that benefits of open kinetic chain exercises outweigh closed ones (P = 0.001). Conclusion: Overall, both exercises were efficient in relieving pain as well as improving function, however open kinetic chain exercises were more contributory.

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