Intensity of Resistance Exercise and Its Effects on Pain, Functionality, and Quality of Life in Adults with Fibromyalgia: A Systematic Review

Background: Fibromyalgia is a chronic rheumatological disease that affects the musculoskeletal system, primarily characterized by widespread chronic pain and other symptoms that significantly impact the quality of life of those who suffer from it, being more prevalent in the female population. In this context, among the non-pharmacological treatments available for this condition, resistance exercise has shown to be a promising intervention. The aim of this systematic review was to determine the optimal intensity of resistance exercise in patients with fibromyalgia and evaluate its effects and benefits. Methods: An exhaustive literature search was carried out in the PubMed, Scopus, SciELO, Web of Science, ScienceDirect, and PEDro databases. After the selection process, from the 405 studies initially identified, 17 met the established inclusion criteria. Subsequently, the methodological quality of the studies was evaluated using the Cochrane RoB 2 tool. Results: From the 405 studies initially identified, 17 met the established inclusion criteria. The results indicate that among the interventions studied, progressive intensity is the most recommended, where it is suggested to start with 40% of 1RM. This is followed, in order of recommendation, by low- and medium-intensity exercises, while high-intensity exercises are, in principle, the least used. Furthermore, the analysis of the effects of progressive intensity exercise showed promising results, including a significant decrease in pain, an increase in physical functionality, and, consequently, an improvement in quality of life. Conclusions: These findings suggest that progressive resistance exercise is an effective intervention for treating patients with fibromyalgia.