Objective: To assess the effectiveness of isolated resistance training on arthritis symptoms, physical performance, and psychological function in people with knee osteoarthritis.
Methods: A comprehensive systematic database search for randomized controlled trials was performed. Two reviewers independently assessed studies for potential inclusion. Study quality indicators, arthritis symptoms, muscle strength, functional performance, and psychological outcomes were extracted. The relative effect sizes (ES) were calculated with 95% confidence intervals.
Results: Eighteen studies enrolling 2,832 subjects were reviewed; the mean cohort age range was 55-74 years. In general, the quality of the reviewed literature was moderately robust; on average, 8 out of 12 quality criteria were accounted for in the reviewed literature. Self-reported measures of pain, physical function, and performance, along with muscle strength (mean 17.4%), maximal gait speed and chair stand time, and balance improved significantly following resistance training in 56-100% of studies where they were measured. Limitations included lack of data available for ES calculations and lack of adverse event and compliance reporting, particularly with regard to the actual training intensity versus the prescribed training intensity.
Conclusion: Resistance training improved muscle strength and self-reported measures of pain and physical function in over 50-75% of this cohort; 50-100% of the studies reported a significant improvement in all but 1 performance-based physical function measure (walk time). The effects of resistance training on health-related quality of life and depression are yet to be confirmed. More research needs to be conducted to establish dose-response relationships and the effect of resistance training on long-term disability, disease pathology, and progression.