Introduction and objective:
Rheumatoid arthritis (RA) is an inflammatory and systemic autoimmune disease that affects peripheral joints leading to joint degradation, pain, deformities, decreased activities of daily living, and sedentary lifestyle, resulting in secondary sarcopenia. Osteoarthritis (OA), in turn, is a multifactorial disease associated with joint degeneration and impairment of the musculoskeletal system as a whole, affecting joint movement and stability. In both pathologies, there is loss of muscle mass and functional impairment, and physical exercise is a therapeutic alternative to minimize these consequences. The aim of the review is to demonstrate the effects of different physical exercise modalities on muscle mass loss in murine models of OA and RA

Materials and method:
The databases used were PUBMED, EMBASE, Cochrane Database, LILACS, and Google Scholar. The review included studies which induced experimental models of OA or RA in rats or mice; used any exercise modality as an intervention; and analyzed some quantitative muscle histomorphometric measurs. The search strategy included all keywords on the topic identified in previous research and adapted for each database. Studies published in any language and in any year were included. An analysis of the studies was performed by two independent reviewers and data were extracted from the articles using tools developed by the reviewers.

Results:
After completing the definitive search in the databases, 193 studies were found, of which only 2 were included in this review, one addressing the effects of resistance exercise in rats with RA, and another using aerobic exercise to treat rats with OA.

Conclusion:
Treatment with different forms of physical exercise contributed to attenuation of muscle mass loss in animal models of OA and RA.