Comparative Effects of Clam Shell Exercises and Short Arc Quadriceps Strengthening Exercises on Pain, Functional Disability and Quality of Life in Patellofemoral Pain Syndrome
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Background: Patellofemoral pain syndrome is a common musculoskeletal condition characterized by anterior or retropatellar knee pain, functional limitation, and reduced quality of life. Exercise therapy is central to conservative management, but direct comparative evidence between commonly prescribed hip-focused and knee-focused exercises remains limited. Objective: To compare the effects of clam shell exercises and short arc quadriceps strengthening exercises on pain, functional disability, and quality of life in patients with patellofemoral pain syndrome. Methods: An assessor-blinded randomized controlled trial was conducted among 34 adults with patellofemoral pain syndrome. Participants were allocated equally into a clam shell exercise group and a short arc quadriceps exercise group, with 17 participants in each group. Both groups received supervised exercise intervention for six weeks. Pain was assessed using the Numeric Pain Rating Scale, functional disability using the Kujala Anterior Knee Pain Scale, and quality of life using the SF-36 Health Survey. Between-group post-intervention comparisons were performed using the Mann–Whitney U test for NPRS and independent-samples t-tests for Kujala and SF-36 scores. Results: Post-intervention outcomes favored the clam shell group. Median NPRS was lower in the clam shell group than in the SAQ group (2.00 vs. 3.00; U = 51.00, p = 0.001). Kujala scores were higher in the clam shell group (89.00 ± 2.29 vs. 84.76 ± 1.64; p < 0.001), and SF-36 scores also favored the clam shell group (83.88 ± 2.69 vs. 77.59 ± 2.09; p < 0.001). Conclusion: Clam shell exercises demonstrated more favorable short-term post-intervention outcomes than short arc quadriceps strengthening exercises for pain, function, and quality of life in patients with patellofemoral pain syndrome. Further trials with baseline-adjusted analyses and longer follow-up are recommended.
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