The purposes of this study are to: 1) compare baseline muscle and cardiovascular health in older individuals (\>60 years old) diagnosed with MS to age-matched people without MS, 2) determine muscle and whole body changes to an exercise training program, 3) determine if the muscle in a more affected leg in individuals diagnosed with MS is different from the muscle of a less affected leg, and 4) if or how individuals diagnosed with MS adapt differently than age-matched people without MS to exercise training. Participation in this study will average 1.5 hours per visit, 3 visits per week, for approximately 4 months.