The purposes of the research are to determine the association of gait performance with lower extremity muscle fatigability and strength measures, and create a preliminary model that can better explain the variance in gait performance based on these muscle performance values. Objective criterion-based measures of physical fatigue (i.e., fatigability) and muscle weakness have been associated with impaired task performance in people with multiple sclerosis (MS). MS-related deficits in muscle capacity result in higher fall risks and a loss of function. However, it is unclear if lower extremity fatigability tests add clinical value to objective strength testing in the rehabilitation and clinical management of MS. Better understanding how patterns of lower extremity (LE) fatigability and strength affect mobility in people with MS could improve outcome measure development and inform rehabilitation strategies.