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.
Department of Exercise Science, University of South Carolina, Columbia, SC 29208; and Department of Behavioral Science, UT-M.D. Anderson Cancer Center Houston, TX 77030
Submitted for publication September 1994.
Accepted for publication April 1995.
The collection of this data was supported with a grant from the National Heart Lung and Blood Institute (HL38131). The authors appreciate the efforts of J. Puhl and K. Greaves for collecting the physical activity data and J. Baranowski for managing the data collection, and C. Spelman for her assistance with preparation of this manuscript.
Address for correspondence: Russell R. Pate, Ph.D., Department of Exercise Science, University of South Carolina, Columbia, SC 29208.