Are exercise booster sessions effective at preserving exercise-induced effects in people with multiple sclerosis? A randomised controlled trial: results from the MSBOOST trial

OBJECTIVES: In people with multiple sclerosis (PWMS), exercise improves aerobic capacity and muscle strength which are key components of physical function and overall health status. However, the effects diminish after exercise cessation. Therefore, the present study aimed to investigate whether exercise booster sessions (EBS) could preserve the exercise-induced improvements.

DESIGN: Multicentre RCT.

METHODS: Ninety-four PWMS performed 12 weeks of aerobic-training (AT) or resistance-training (RT) and were subsequently randomised to receive EBS (two sessions every fifth week) (ATboost n = 24, RTboost n = 24) or usual-care (ATuc n = 20, or RTuc n = 26) for 40 weeks. The primary outcome was physical function measured as a composite score of the six-minute walk test (6MWT) and five-time sit-to-stand test (5STS). Secondary outcomes were aerobic capacity and muscle strength.

RESULTS: No between-group difference was observed in the composite score of 6MWT and 5STS (arbitrary unit) between ATboost and RTboost 0.00 [-0.20; 0.20]. No between-group difference was observed for aerobic capacity (mL O2/kg/min) between ATboost and ATuc 1.1 [-1.9; 4.1], although a within-group change was observed for ATboost -1.9 [-4.0; 0.1], but not for ATuc -3.0 [-5.2; -0.8]. No between-group difference was seen for muscle strength (Nm/kg) between RTboost and RTuc -0.04 [-0.36; 0.28]. Also, no within-group change was observed for neither RTboost -0.07 [-0.30; 0.14] nor RTuc -0.04 [-0.27; 0.20].

CONCLUSIONS: EBS had no apparent effect on preservation of physical function, aerobic capacity, or muscle strength in PWMS. Muscle strength was preserved regardless of group, whereas only ATboost preserved exercise-induced improvements in aerobic capacity.