Research in Nursing & Health, 2006, 29, 597–606 Symptoms, Self-Efficacy, and Physical Activity Among Individuals With Multiple Sclerosis Robert W. Motl,* Erin M. Snook, { Edward McAuley, z Rachael C. Gliottoni { Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, 350 Freer Hall, 906 South Goodwin Ave., Urbana, IL 61801 Accepted 1 July 2006 Abstract: Using social-cognitive theory, we examined the associations among symptoms, self-efficacy, and physical activity in 196 individuals with multiple sclerosis (MS). Participants completed symptoms, self-efficacy, and physical activity measures and wore an accelerometer for 7 days. There was a moderate inverse correlation between symptoms and physical activity (j ¼.42). Subsequent analyses indicated that symptoms had direct negative relationships with self-efficacy (g ¼.32) and physical activity (g ¼.24), and self-efficacy had a direct positive relationship with physical activity (b ¼ .57). This study provides initial support for symptoms as a correlate of physical activity in individuals with MS. Monitoring symptoms during a physical activity program and altering the exercise prescription during symptom exacerbation might be a method for increasing exercise adherence. ß 2006 Wiley Periodicals, Inc. Res Nurs Health 29:597–606, 2006 Keywords: multiple sclerosis; symptoms; exercise; social-cognitive theory; covariance modeling Multiple sclerosis (MS) is the most prevalent neurological disease among young and middle- aged adults in the United States (National Multiple Sclerosis Society [NMSS], 2003). This chronic, progressive, and unpredictable disease involves a presumed inflammatory demyelination of axons in the central nervous system (CNS). The demyelin- ation interferes with the smooth and rapid conduction of electrical potentials along neuronal pathways in the CNS and is associated with MS symptoms (Lublin, 2005). These symptoms are diverse and include motor, sensory, visual, bladder, sexual, and psychological disturbances (NMSS). MS is associated with a dramatic reduction in physical activity behavior. This was demonstrated in a recent meta-analysis of published studies examining physical activity behavior in individ- uals with MS (Motl, McAuley, & Snook, 2005). Effect sizes were computed by comparing physi- cal activity levels of persons with MS versus comparison groups including persons with and without other diseases. There was an overall effect of g ¼.60 (95% CI ¼.44, .77) indicating Correspondence to Robert W. Motl *Assistant Professor. { Research Assistant. z Professor. Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/nur.20161 ß 2006 Wiley Periodicals, Inc.