Study protocol: effects of exercise booster sessions on preservation of exercise-induced adaptations in persons with multiple sclerosis, a multicentre randomised controlled trial-the MS BOOSTER trial.

Introduction: Multiple sclerosis (MS) causes a broad range of symptoms, with physical function being one of the most disabling consequences according to patients themselves. Exercise effectively improves lower extremity physical function. Nonetheless, it is unknown which exercise modality is most effective and it remains challenging to keep persons with MS adhering to exercise over a longer period. Therefore, the present study aims to investigate how exercise booster sessions (EBS) influence the sustainability of exercise-induced effects on physical function, and furthermore, to investigate which exercise modality (aerobic training or resistance training) is most effective in terms of improving physical function.

Materials And Methods: This study is a multi-arm, parallel-group, open-label multicentre randomised controlled trial investigating the effects of EBS. Participants (n=150) are initially randomised to 12 weeks of either resistance training+usual care, aerobic training+usual care or usual care. After 12 weeks of intervention, participants in the exercise groups will again be randomised to either EBS+usual care or usual care during a 40-week follow-up period. The primary outcome is physical function (composite score based on 6-min walk test and five-time sit to stand), and the secondary outcomes are fatigue, cognition, physical activity, symptoms of depression and quality of life.

Ethics And Dissemination: The study is approved by the Central Denmark Region Committees on Health Research Ethics (1-10-72-237-21) and is registered at the Danish Data Protection Agency (2016-051-000001) and at Clinicaltrials.gov (NCT04913012). All study findings will be published in scientific peer-reviewed journals and presented at scientific conferences.

Trial Registration Number: NCT04913012.