Abstract
BACKGROUND: The aim of this study was to systematically evaluate and synthesize the available evidence on the effects of resistance/strength training on physical function, stiffness, pain, and quality of life of patients with knee osteoarthritis (KOA). MATERIALS AND METHODS: A systematic search of electronic databases, including PubMed, Scopus, WOS, and the Cochrane Library, was performed to identify trials published up to December 2024 evaluating the effects of resistance/strength training on KOA. Eligible studies included interventions targeting pain, stiffness, physical function, or quality of life, compared to control or alternative exercise groups. Pooled effect sizes were calculated using fixed and random effects models based on the degree of heterogeneity observed among the studies, with the random effects model applied due to significant variability in outcomes. RESULTS: A total of 21 randomized controlled trials, including 2,345 participants, were analyzed. Resistance training significantly improved physical function (MD=-3.02, P0.01) and reduced stiffness (MD=-0.46; P=0.03). Pain outcomes showed mixed results, with significant reductions observed on the WOMAC pain scale (MD=-0.83, P=0.04), but not consistent effects across other measures such as the VAS. CONCLUSION: Resistance training improves physical function and stiffness in KOA, with mixed effects on pain and no significant impact on quality of life. High heterogeneity highlights the need for standardized protocols. Resistance training is a valuable component of knee OA management.