Effects of resistance training on muscle mass, strength, and physical function in older women with sarcopenia: a systematic review and meta-analysis.

Background and objective: Resistance training is widely recommended for sarcopenia, yet evidence in older women remains limited. This study systematically evaluated its effects on muscle mass, strength, and physical function in this population. Methods: PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched up to February 2025; the protocol was registered in PROSPERO (CRD420251066233). Meta-analyses were performed using the "meta" package in R under a random-effects model with restricted maximum likelihood estimation. Study quality was assessed using RoB 2, and evidence certainty via GRADE. Results: Twelve randomized controlled trials involving 518 older women with sarcopenia were included. Resistance training significantly improved handgrip strength (SMD = 0.43, 95% CI: 0.11-0.74), gait speed (SMD = 0.37, 95% CI: 0.09 to 0.64), knee extension strength (SMD = 0.85, 95% CI: 0.37 to 1.33), Timed Up and Go (SMD = -0.68, 95% CI: -0.95 to -0.41), and 30-Second Chair Stand (SMD = 0.52, 95% CI: 0.19 to 0.86), but had no significant effect on skeletal muscle mass index. Subgroup analyses showed that women with sarcopenic obesity achieved greater gains in knee extension strength, while those with sarcopenia alone improved more in gait speed. Mixed resistance training demonstrated a significant advantage in enhancing gait speed. Conclusion: Resistance training effectively enhances muscle strength and physical function in older women with sarcopenia, though improvements in muscle mass remain uncertain. Further large-scale, long-term studies are needed to confirm these findings and optimize intervention protocols.