Effects of Muscle Strength Training on Muscle Mass Gain and Hypertrophy in Older Adults With Osteoarthritis: A Systematic Review and Meta-Analysis

Objective To investigate the effect of muscle strength exercise training (MSET) on lean mass (LM) gain and muscle hypertrophy in older patients with lower extremity osteoarthritis (OA). Methods A comprehensive search of online databases was performed on April 20, 2019. Randomized controlled trials (RCTs) that reported the effects of MSET on LM, muscle thickness, and cross-sectional area (CSA) in older patients with OA were identified. A risk of bias assessment and meta-analysis were performed for the included RCTs. Results We included 19 RCTs with a median Physiotherapy Evidence Database score of 6 of 10 (range 3-7). In total, data from 1,195 patients (65% women, 85% with knee OA) with a mean age of 62.1 years (range 40-86 years) were analyzed. MSET resulted in significantly higher LM gain (standardized mean difference [SMD] 0.49 [95% confidence interval (95% CI) 0.28, 0.71], P < 0.00001) than did the nonexercise controls. Meta-analysis results revealed significantly positive effects of MSET on muscle thickness (SMD 0.82 [95% CI 0.20, 1.43], P = 0.009) and CSA (SMD 0.80 [95% CI 0.25, 1.35], P = 0.004) compared with nonexercise controls. No significant effects in favor of MSET were observed for any muscle outcome compared with exercise controls. Five RCTs reported nonsevere adverse events in response to MSET, whereas no RCTs reported severe events. Conclusion MSET is effective in increasing LM and muscle size in older adults with OA. Clinicians should incorporate MSET into their management of patients at risk of low muscle mass to maximize health status, particularly for older individuals with OA.