A growing body of work suggests that regular exercise can support symptom management and improve physical function for people living with multiple sclerosis (MS). Although exercise is known to be beneficial for managing many symptoms related to MS, its effects on the central nervous system, and whether these effects change with different types of exercise, are not well understood. Here, the investigators have designed a clinical trial that compares the effects of distinct exercise protocols on aspects of physical function, physical fitness, and central nervous system function. This research will be the first to compare the effects of different types of exercise on central nervous system changes in people with MS.