A Cochrane review included 121 RCTs with a total of 6700 subjects over 60 years of age. The participants in 59 trials were healthy older adults; in the remaining 62 trials, the participants had a health problem, functional limitation and/or were residing in a hospital or residential care. In most trials, progressive resistance training (PRT) was performed 2 to 3 times per week and at a high intensity. The primary outcomes were of physical function and secondary outcomes of measures of impairment and functional limitation. PRT resulted in a small but significant improvement in physical ability (33 trials, 2172 participants; SMD 0.14, 95% CI 0.05 to 0.22). Functional limitation measures also showed improvements: e.g. there was a modest improvement in gait speed (24 trials, 1179 participants, MD 0.08 m/s, 95% CI 0.04 to 0.12); and a moderate to large effect for getting out of a chair (11 trials, 384 participants, SMD -0.94, 95% CI -1.49 to -0.38). PRT had a large positive effect on muscle strength (73 trials, 3059 participants, SMD 0.84, 95% CI 0.67 to 1.00). Participants with osteoarthritis reported a reduction in pain following PRT (6 trials, 503 participants, SMD -0.30, 95% CI -0.48 to -0.13). There was no evidence from 10 other trials (587 participants) that PRT had an effect on pain.
Comment: The quality of evidence is downgraded by study quality (inadequate allocation concealment), inconsistency (heterogeneity in participants, interventions and outcomes) and imprecise results (limited study size in most of the studies).