Effects of bariatric surgery on muscle strength and quality: A systematic review and meta-analysis

Obesity is a major health burden worldwide. Although bariatric surgery (BS) is recognized as an effective strategy for weight loss and comorbidities improvement, its impact on muscle strength and quality is still unclear. We aimed to examine postoperative changes in muscle strength and quality and their relationship with body mass index (BMI) changes among adults undergoing BS. To this end, we systematically searched the WoS, PubMed, EBSCO, and Scopus databases. The meta-analyses, which included 24 articles (666 participants), showed that BS reduces absolute lower-limb isometric strength (ES = -0.599; 95% CI = -0.972, -0.226; p = 0.002). Subjects who experienced a more significant reduction in BMI after BS also suffered a higher loss of absolute muscle strength. Similarly, absolute handgrip strength showed a significant decrease (ES = -0.376; 95% CI = -0.630, -0.121; p = 0.004). We found insufficient studies investigating medium- and long-term changes in muscle strength and/or quality after BS. This study provides moderate-quality evidence that BS-induced weight loss can reduce the strength of appendicular muscles in the short term, which should be addressed in management these subjects. More high-quality studies are needed to evaluate the impact of BS on muscle strength and the different domains of muscle quality in the medium and long term (registered on PROSPERO CRD42022332581).