Effects of resistance training on the physical symptoms and functional capacity of patients with fibromyalgia: a systematic review and meta-analysis of randomized clinical trials.

Background: Resistance training (RT) has become an important topic for the treatment of fibromyalgia (FM); however, there are still controversies regarding its ability to significantly improve physical symptoms and a lack of adequate recommendations for evidence-based practice.

Aim: The aim of this study is to analyze the effects of RT on the physical symptoms of patients with FM through a systematic review with meta-analysis.

Methods: We conducted a systematic review of randomized controlled trials in June 2022, according to PRISMA recommendations. The searches were carried out on the databases PubMed, Embase, Science Direct, Web of Science, PEDro, CINAHL, SciELO, and Google Scholar for gray literature, and the protocol was recorded in PROSPERO. Studies that evaluated patients with FM undergoing an RT program lasting more than 2 weeks and that analyzed physical health were selected. To carry out the meta-analysis, the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions were followed.

Results: In total, 13 studies were included for qualitative analysis and nine for meta-analysis. Regarding meta-analysis, a favorable improvement was found for pain ([MD =  - 10.22 (95% CI: - 18.86 to - 1.58; I: 64%; P for heterogeneity: 0.003)]; very low quality of evidence {QoE}), fatigue ([SMD =  - 0.39 (95% CI: - 0.61 to - 0.17; I: 0%; P = 0.91)]; moderate QoE), and muscle strength ([SMD = 0.94 (95% CI: 0.02 to 1.85; I: 93%; for heterogeneity: < 0.0001)]; very low QoE) and improvement in functional capacity ([MD = 18.75 (95% CI: 4.27 to 33.22; I: 39%; P = 0.19)]; low QoE), in the general comparison.

Conclusion: RT was effective in reducing pain and fatigue and increasing strength and functional capacity; however, due to the quality of the evidence, more studies are needed.