FIT-ATOMIC Exercise Feasibility Trial

This multi-center, randomized controlled feasibility trial will assess a 20-week home-based exercise intervention in youth with Multiple Sclerosis (MS). The goal is to determine the feasibility of conducting a larger, definitive trial on exercise training as a non-pharmacological approach to improve disease outcomes in this population. Participants will be randomized to either an Exercise Training group or a Mobility and Flexibility Training group. The investigators will evaluate differences between the two groups in physical activity levels, mediators of physical activity, and psychosocial outcomes. Assessments, including clinical exams, brain MRI, eye tracking, cognitive testing, blood draws, and questionnaires, will occur at baseline and after 20 weeks. Accelerometry will be done at baseline, 10 weeks, and 20 weeks to track physical activity. The primary objectives are to assess the feasibility of recruiting, retaining, and randomizing youth with MS and to evaluate adherence to the exercise intervention and coaching sessions. Exploratory objectives include examining changes in depressive symptoms, cognitive function, blood biomarkers (BDNF and irisin), brain volume, and fitness levels in response to the intervention. Approximately 40 participants will be enrolled from four sites in Canada and the United States. Primary outcomes include feasibility, acceptability, and fidelity measures. Exploratory outcomes include blood biomarkers, brain MRI, cognitive testing, and other neuropsychological measures.