Intra-individual variation in children's physical activity patterns: Implications for measurement

Authors

Kate Ridley, Flinders UniversityFollow
Tim Olds, University of South AustraliaFollow
Beth P. Hands, University of Notre Dame AustraliaFollow
Dawne Larkin, University of Western AustraliaFollow
Helen Parker, University of Notre Dame AustraliaFollow

Publication Details

Ridley, K., Olds, T., Hands, B. P., Larkin, D., & Parker, H. (2009). Intra-individual variation in children's physical activity patterns: Implications for measurement. Journal of Science and Medicine in Sport, 12 (5), 568-572.
https://doi.org/10.1016/j.jsams 2008.09.009

Abstract

Children's physical activity (PA) patterns change form day to day. This intra-individual variability affects precision when measuring key physical activity and sedentary behavior variables. This paper discusses strategies to reduce the random error associated with intra-individual variability and demonstrates the implications for assessing PA when varying number of days are sampled. Self-reported data collected on two hundred and ninety eight 13- to 14-year-olds were used to compare estimates of PA and sedentary behaviour derived from between 1 and 7 days of recall data. Large intra-individual coefficients of variation were calculated for physical activity level (14.5%), moderate-to-vigorous physical activity (83.4%), screen time (60.8%) and sleep (12.2%). While the magnitude of error associated with estimating means decreased as more days were sampled, the paper notes that depending on the nature of the research question being asked, fewer days may yield sufficiently precise estimates. Therefore, researchers should conduct power analyses based on estimated inter- and intra-individual variability and sample size to determine how many days to sample when assessing children's PA patterns.

Keywords

Peer-reviewed, motor activity, adolescent, child, Raine study, self-report