text: 1 Introduction 
  
  Multiple sclerosis (MS) is a progressive inﬂammatory disease of 
  the central nervous system (CNS) that is typically diagnosed at 30– 
  40 years of age (1). A great concern is the signiﬁcantly lower levels 
  of physical activity (PA) in people with MS (pwMS) across 
  disability levels than in their healthy counterparts (2, 3). 