Increasing Physical Activity for Adults With Multiple Sclerosis (MS)

Inclusion Criteria: * Provider-confirmed diagnosis of MS using revised 2017 McDonald criteria * \> 18+ years of age * Patient determined disease steps (PDDS) score \< 3, indicating the potential for some gait disability although typically ambulates without an assistive device * Insufficiently active, defined as \< 150 minutes of physical activity per week, assessed using the PAVS in the EHR in clinics as part of the routine patient intake process * Use of an iPhone with software version iOS13+ or an Android phone 4.1+ * Agree to install and use the ExerciseRx app for the entire study period and keep their phone on them during the daytime (e.g., pocket, bags, hands) Exclusion Criteria: * Recent (past 4 weeks) or planned surgery during the study period which may impact engaging in step counts * MS relapse within the last 30 days * Plans to travel internationally during the study period, which could interfere with server uploads of mobile phone data * Those at a higher risk of falling or injury from falls or unable to safely exercise due to other medical conditions (e.g. heart conditions, diabetes or conditions made worse by walking or physical activity)