Evaluation of sex-based differences in resistance exercise training-induced changes in muscle mass, strength, and physical performance in healthy older (≥60 y) adults: A systematic review and meta-analysis

The objective of this systematic review and meta-analysis was to determine if there are sex-based differences in adaptations to resistance exercise training in healthy older adults. Following the screening process, data from 36 studies comparing older males and females (602 males; 703 females; ≥60 years of age) for changes in skeletal muscle size, muscle strength, and/or physical performance following the same resistance exercise training intervention were extracted. Mean study quality was 16/29 (modified Downs and Black checklist), considered moderate quality. Changes in absolute upper-body (Effect Size [ES] = 0.81 [95% CI 0.54, 1.09], P < 0.001), and lower-body (ES = 0.40 [95% CI 0.24, 0.56], P < 0.001) strength were greater in older males than females. Alternatively, changes in relative upper-body (ES = -0.46 [95% CI -0.77, -0.14], P < 0.01), and lower-body (ES = -0.24 [95% CI -0.42, -0.06], P < 0.01) strength were greater in older females than males. Changes in absolute, but not relative, whole-body fat-free mass (ES = 0.18 [95% CI 0.04, 0.33], P < 0.05) were greater in older males than females. There were no sex-based differences for absolute or relative changes in limb muscle size, muscle fiber size, or physical performance.