Effects of resistance training on exercise ability in chronic obstructive pulmonary disease subjects: A systematic review and meta-analysis

Introduction The resistance exercise effect on the exercise ability in chronic obstructive pulmonary disease (COPD) subjects has drawn considerable attention. However, the relationship between resistance exercise and the exercise ability of COPD subjects is conflicting. This meta-analysis was performed to evaluate this relationship. Methods A systematic-literature search up to July 2020 was performed in OVID, Embase, Cochrane Library, PubMed, Google scholar for randomised control trials reported relationships between resistance exercise and the exercise ability of COPD subjects, and 13 studies were detected with 1286 subjects at the baseline. Mean differences (MD) with 95% confidence intervals (CIs) were calculated comparing the resistance exercise and the exercise ability of COPD subjects using the continuous method with a random or fixed-effect model. Results A significantly higher 6-minutes walk test was observed in subjects performing resistance training (MD, 60.41; 95% CI, 39.97-80.85, P < .001) compared with non-resistance training subjects. However, no significant difference was observed between COPD subjects performing resistance exercise compared with non-resistance training COPD subjects in constant work rate cycle endurance test (MD, 1.59; 95% CI, 0.03-3.15, P = .05), unsupported upper extremity exercise test (MD, 48.77; 95% CI, -1.20 to 98.75, P < .06) and quality of life questionnaires (MD, -0.62; 95% CI, -2.49 to 1.245, P < .51). Conclusions The resistance exercise significantly increases the 6-minutes walk test in COPD subjects. However, resistance exercise did not significantly affect the constant work rate cycle endurance test, unsupported upper extremity exercise test and quality of life questionnaires. This relationship forces us to recommend the resistance exercise to improve the 6-minutes walk test as a simple and easy evaluation of functional exercise ability in COPD subjects.