The effects of behavioral interventions on muscle cross-sectional area in patients with myotonic dystrophy type-1 (MD1). The study includes 27 MD1 patients who underwent either cognitive behavioral therapy or graded exercise plus behavioral therapy. The authors conclude that behavioral intervention targeting physical activity increases lower extremity muscle cross-sectional area. However, several shortcomings are noted. It is unclear which patients from previous studies were included in the present study, as the number of patients differs. The application of the DM1-Activ scale for documenting graded exercise is also criticized for its lack of standardization and unclear cut-offs. Additionally, comparisons were only made between standard care and the intervention group, not between the graded exercise and behavioral therapy group. The study does not address potential differences in hormone levels, particularly FGF-21, which could influence muscle performance and morphology in MD1 patients.