The goal of this observational study is to compare the impact of eccentric resistance training to traditional resistance training on fatigue in persons with multiple sclerosis (MS). The primary question this study is asking is the following: is eccentric resistance training more fatiguing than traditional resistance training in persons with MS?. Participants will be asked to come for two sessions for two weeks. In the first week, subjects will undergo a bout of either traditional or eccentric resistance training. The next day they will return to assess their level of fatigue. The following week the subject will return and undergo whatever type of training they did not experience the first week, and it's effects on fatigue will again be assessed. The difference between the subjects level of fatigue for either condition will be compared.

Persons with multiple sclerosis (MS) have mobility deficits. Exercise is commonly used to treat these mobility deficits, but must be done so judiciously in order to limit the effects of fatigue, one of the most common disease findings. In persons with MS ,fatigue can limit the amount of exercise performed. Eccentric training, where a muscle is lengthened under resistance has been shown to produce greater gains in strength with less energy expenditure when compared to traditional strength training where a muscle is both lengthened and shortened under resistance. However, eccentric strength training has been shown to result in delayed onset muscle soreness, which may also limit how much exercise a person with MS can perform. The purpose of the study is to compare the impact of eccentric versus traditional strength training programs on fatigue and persons with multiple sclerosis. The hypothesis is that there will be no difference in fatigue measurements between the two conditions. If the hypothesis is correct, it will suggest that eccentric training should be the subject of further study to assess it's feasibility and effectiveness, in treating mobility deficits in person with multiple sclerosis.

A randomized crossover design will be used. Ambulatory participants with a diagnosis of MS will be randomized into either a eccentric or traditional training condition. Each training condition will consist of a single session of training. The following day, the patient will return and their levels of fatigue assessed. The next week, the subjects will return and crossover, undergoing whatever type of training they did not experience in the previous week, and the impact of the training will again be assessed.

Inclusion Criteria:

• Definitive diagnosis of Multiple Sclerosis.
• Ability to walk for 6 minutes continuously with or without assistive device
• Ability read, understand and sign and informed consent

Exclusion Criteria:

• Evidence of recent exacerbation in the last 2 months prior to starting the study
• Orthopedic, cardiopulmonary, or non -MS neurologic condition that could interfere with carrying out the study protocol

Ambulatory persons with MS