Feasibility of a High-intensity Interval Training Program in Persons With Multiple Sclerosis Who Have Walking Disability

There is considerable evidence to support the efficacy of moderate intensity continuous (MIC) exercise benefitting clinically-relevant outcomes in persons with multiple sclerosis (MS). However, persons with MS who have walking impairments (pwMS-wd) are severely deconditioned and may achieve superior benefits by engaging in high-intensity interval training (HIIT), especially while utilizing adaptive equipment, such as with recumbent arm/leg stepping (RSTEP). Of the published studies on HIIT in MS, HIIT yielded significant improvements in cardiorespiratory fitness in all but one study. In those studies that directly compared HIIT to MIC exercise, the data indicated a potential superiority of HIIT as compared to MIC in improving physiological conditioning in a time efficient manner. However, this evidence is specific to those with MS with mild to moderate disability engaging in cycle/arm ergometry and an investigation of HIIT in pwMS-wd is needed as the feasibility and potential benefits of engaging in HIIT in pwMS-wd is relatively unknown.

The primary aim of the proposed study is to assess the feasibility of a 12-week, RSTEP HIIT program in pwMS-wd. The secondary aim is to examine changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depressive symptoms as clinically-relevant efficacy outcomes following the 12-week, RSTEP HIIT intervention. It is hypothesized that the intervention will be feasible and lead to positive changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depressive symptoms. This work is informed by recently published data, which indicate that a single bout of RSTEP HIIT taxes the cardiorespiratory system significantly more than MIC exercise, yet without untoward effects on walking, gait, cognition, mood, or enjoyment. These data suggest that RSTEP HIIT may be an acceptable, safe, and tolerable stimulus for chronic exercise training.