An exploratory study of two measures of free-living physical activity for people with multiple sclerosis

Abstract

Objective: To examine the ability of two measures of physical activity (tri-axial accelerometer and activity diary) to discriminate among groups of inactive, moderately active and active individuals with multiple sclerosis and to explore the relationship between these two measures. Design: Exploratory, descriptive study. Subjects: Thirty individuals with multiple sclerosis and nine controls. Protocol: Individuals with multiple sclerosis were recruited to inactive, moderately active and active groups as defined by Adjusted Activity Scores from the Human Activity Profile. Control participants were recruited to an active group. Free-living physical activity was recorded over four consecutive days. Main measures: A TriTrac RT3 accelerometer and a self-report physical activity diary were used to measure activity. Results: Thirty-six participants completed data collection. For the participants with multiple sclerosis, both the accelerometer (P = 0.004) and the diary (P = 0.006) detected significant differences between inactive and active groups. The accelerometer also detected a significant difference between moderately active and active groups (P = 0.04). In contrast, the diary detected a significant difference between inactive and moderately active groups (P = 0.05). Accelerometer and diary scores were significantly correlated (r = 0.59). Accelerometer scores were significantly correlated with neurological status (rs = -0.64). Conclusions: Both measures readily differentiated least active from most active groups. The accelerometer also differentiated moderately active from active groups, suggesting suitability for use in detecting change in more active client groups, while the diary differentiated inactive from moderately active groups, suggesting suitability for use in detecting change in less active groups.