Effect of physical exercise on muscle strength in adults following bariatric surgery: A systematic review and meta-analysis of different muscle strength assessment tests

Individuals following bariatric surgery are considered at high risk for the development of sarcopenic obesity (excess fat mass, low muscle mass and low physical function), and exercise may play an important role in its prevention and treatment. We systematically reviewed 5 scientific databases (Embase, Medline, Scopus, SPORTDiscus, and Web of Science) and 2 grey literature databases (ProQuest and Google Scholar) for clinical trials that evaluated the effect of exercise on muscle strength in adults following bariatric surgery and conducted a separate meta-analysis for studies that used different muscle strength tests. Random-effect models, restricted maximum likelihood method and Hedges' g were used. The review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42020152142). Fifteen studies were included (638 patients), none had a low risk of bias, and all were included in at least 1 of the 5 meta-analyses (repetition maximum [lower and upper limbs], sit-to-stand, dynamometer, and handgrip tests). Exercise interventions improved both upper (effect size, 0.71; 95% CI, 0.41-1.01; I-2 = 0%) and lower (effect size, 1.37; 95% CI, 0.84-1.91; I-2 = 46.14) limb muscle strength, as measured by repetition maximum tests. Results were similar for the sit-to-stand (effect size, 0.60; 95% CI, 0.20-1.01; I-2 = 68.89%) and dynamometer (effect size, 0.46; 95% CI, 0.06-0.87; I-2 = 31.03%), but not for the handgrip test (effect size, 0.11; 95% CI, -0.42-0.63; I-2 = 73.27%). However, the certainty level of the meta-analyses was very low. Exercise with a resistance training component performed post bariatric surgery may improve muscle strength, which is related to sarcopenic obesity, functional capacity, and mortality risk, therefore should be included in the follow-up.