Physical activity and health related physical fitness in children with juvenile idiopathic arthritis

Objective: To obtain insight into the interaction between daily physical activity and components of health related physical fitness in children with juvenile idiopathic arthritis. Methods: Forty five patients (10 male/35 female; mean (SD) age 8.9 (2.2) years) participated in the study. Body mass, height, skinfold thickness, number of swollen joints, and joint range of motion were determined. The maximal oxygen consumption (VO2peak) was assessed during a graded maximal bicycle exercise test. Daily physical activity levels were measured with a Caltrac activity monitor and a parental physical activity rating (PAL) on a five point Likert scale. Results: Partial correlation coefficients (to control for age) between physical activity and indices of health related physical fitness showed significant relationships between Caltrac motion counts and absolute VO2peak (r=0.31) and relative VO2peak (r=0.34), but not with the indices of body composition. There was also a significant correlation between PAL and relative VO2peak (r=0.33). Conclusions: Physical activity was significantly related to cardiorespiratory fitness but not to body composition in children with juvenile idiopathic arthritis. A longitudinal follow up should show whether an active lifestyle protects for loss of aerobic fitness in this patient group.