Forced Exercise Training for Persons with Multiple Sclerosis

Background: Exercise has been shown to alleviate symptoms in persons with multiple sclerosis (PwMS); however, it is a challenge for PwMS to exercise with sufficient intensity to illicit the neurophysiological effects necessary to alter CNS function and modify long-term prognosis. Forced aerobic exercise (FE) is a method to augment the voluntary efforts of individuals so that they can exercise at intensities beyond what can be achieved on their own. FE training has shown promising results in persons with Parkinson’s Disease and stroke but has not been studied in PwMS.

Objectives: This pilot study aimed to investigate the feasibility and initial efficacy of applying FE training to PwMS to improve motor function and quality of life (QOL).

Methods: Individuals (n=14) were randomized to FE (n=7) or voluntary aerobic exercise (VE, n=7). All participants completed 24 exercise sessions over 12 weeks. The FE intervention consisted of forced-rate aerobic exercise on a stationary semi-recumbent bicycle custom-engineered to augment cycling to a programed target cadence. Participants in the voluntary aerobic exercise (VE) group cycled at their self-selected cadence without assistance. Exercise training variables including session duration, aerobic intensity, and rhythm were recorded. Participants completed biomechanical gait analysis, the 6-minute walk test, and the PROMIS-29 assessment.

Results: Five participants (FE=3, VE=2) have completed the intervention and all testing, seven remain in the intervention phase, and two have withdrawn from the study. No adverse events related to the intervention have occurred. The average session duration for the FE and VE groups was similar, at 43.7 and 43.1 min, respectively. Average aerobic intensity for the FE and VE groups was 67.1 and 71.1% of age-predicted maximum heart rate, respectively. Exercise cadence was significantly higher for the FE group at 76.3 revolutions per minute (RPM) compared to 58.2 RPM for the VE group (P<.01). Modest improvements in walking capacity were observed from 371.5 to 377.1 m. Walking speed was unchanged from 0.53 to 0.54 m/s.

Conclusions: Participants tolerated both modes of moderate- to high-intensity aerobic cycling without adverse events. The FE and VE groups achieved comparable metrics as it relates to exercise duration and aerobic intensity; however, the FE group achieved higher cadence. Participants demonstrated modest improvements or no change in gait velocity and walking capacity.