Reliability of Scores From Physical Activity Monitors in Adults With Multiple Sclerosis

We examined the reliability of scores from physical activity monitors in a sample of 193 individuals with multiple sclerosis (MS) who wore a pedometer and an accelerometer for a 7-day period. There were no significant differences among days for the pedometer (p =.12) or the accelerometer (p =.15) indicating that week and weekend days can be analyzed in a single intra-class correlation (ICC) analytic model. The 7 days of monitoring yielded ICC estimates of.93 for both the pedometer and accelerometer, and a minimum of 3 days yielded a reliability of.80 for both the pedometer and accelerometer. Results indicated that physical activity monitor scores are reliable measures of physical activity for individuals with MS. Multiple sclerosis (MS) is the most prevalent neurological disease among young and middle-aged adults in the United States (National Multiple Sclerosis Society, 2003), and increasing attention is being directed toward understanding physical activity behavior in this population (Motl, McAuley, & Snook, 2005a). The study of physical activity among adults with MS requires evidence for th