Physical activity improves strength, balance and endurance in adults aged 40–65 years: a systematic review

QUESTION: Can physical activity in adults aged 40-65 years enhance strength and balance and prevent falls? DESIGN: Systematic review with meta-analysis of randomised clinical trials. PARTICIPANTS: Healthy adults aged 40-65 years. INTERVENTION: Programs that involved the performance of any physical activity in community settings and workplaces. OUTCOME MEASURES: Strength, balance, endurance, and falls rate. RESULTS: Twenty-three eligible trials were identified and 17 of these were pooled in the meta-analyses. The meta-analysis of strength outcomes found a moderate effect of physical activity on strength (SMD=0.54, 95% CI 0.38 to 0.70). Larger effects were observed from programs that specifically targeted strength (SMD=0.68, 95% CI 0.49 to 0.87), when compared to those that did not (SMD=0.32, 95% CI 0.09 to 0.55). This difference was statistically significant (effect of strength in meta-regression p=0.045). Physical activity also had a moderate effect on both balance (SMD=0.52, 95% CI 0.24 to 0.79) and endurance (SMD=0.73, 95% CI 0.50 to 0.96). No trials reported effects of physical activity on falls soon after receiving the intervention. A statistically non-significant effect on falls 15 years after receiving a physical activity intervention was found in one trial (RR=0.82, 95% CI 0.53 to 1.26). CONCLUSIONS: This review found that muscle strength, balance, and endurance can be improved by physical activity in people aged 40-65 years. There were bigger effects on muscle strength from programs that used resistance exercises, indicating the need to include a resistance training component if strength enhancement is the goal.