title: Tracking of physical activity in young children.
abstract: The purpose of this study was to determine whether physical activity behavior tracks during early childhood. Forty-seven children (22 males, 25 females) aged 3-4 yr at the beginning of the study were followed over a 3-yr period. Heart rates were measured at least 2 and up to 4 d.yr-1 with a Quantum XL Telemetry heart rate monitor. Physical activity was quantified as the percentage of observed minutes between 3:00 and 6:00 p.m. during which heart rate was 50% or more above individual resting heart rate (PAHR-50 Index). Tracking of physical activity was analyzed using Pearson and Spearman correlations. Yearly PAHR-50 index tertiles were created and examined for percent agreement and Cohen's kappa. Repeated measures ANOVA was used to calculate the intraclass correlation coefficient across the 3 yr of the study. Spearman rank order correlations ranged from 0.57 to 0.66 (P < 0.0001). Percent agreement ranged from 49% to 62%. The intraclass R for the 3 yr was 0.81. It was concluded that physical activity behavior tends to track during early childhood.
authors.affiliation: Department of Exercise Science, University of South Carolina, Columbia 29208, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Pate
authors.forename: T
authors.initials: T
authors.lastname: Baranowski
authors.forename: M
authors.initials: M
authors.lastname: Dowda
authors.forename: S G
authors.initials: SG
authors.lastname: Trost
mesh_terms: D002675:Child, Preschool; D005260:Female; D015438:Health Behavior; D006339:Heart Rate; D006801:Humans; D008297:Male; D005082:Physical Exertion