title: Do children take the same number of steps every day?
abstract: The purpose of this study was to examine the day-to-day variability in pedometer-assessed physical activity (steps/day). A total of 1,443 children aged 6-12 years from the United States (195 boys, 254 girls), Sweden (257 boys, 252 girls), and Australia (229 boys, 256 girls) wore a pedometer for 4 consecutive weekdays. Repeated measures analysis of variance was used to examine daily differences in steps/day and the coefficient of variation (CV) was calculated for each individual to describe the day-to-day variability. Overall, mean steps/day were higher among boys (14,698 +/- 3,373 steps/day) than girls (12,086 +/- 2,929 steps/day). Significant differences were found between the 4 monitoring days for the entire sample; however, the absolute mean differences were small (55-958 steps) with an overall effect size of 0.01. This trend was apparent regardless of age, gender, and country. Individual CVs ranged from approximately 2 to 88% and the overall mean CV approximated 22%. An age-related increase in the mean CV was observed between 6- and 12-year-old children. The age x gender x country interaction was not significant (P > 0.05). These findings have implications toward the proper design, analysis, and interpretation of studies regarding physical activity among children. Beyond this aspect, our results lend insight into potential age-related biological mechanisms that may also influence daily levels and patterns of physical activity.
authors.affiliation: Department of Exercise and Sports Science, University of Tulsa, Tulsa, Oklahoma 74104, USA. eric-wickel@utulsa.edu
authors.forename: Eric E
authors.initials: EE
authors.lastname: Wickel
authors.forename: Joey C
authors.initials: JC
authors.lastname: Eisenmann
authors.forename: Robert P
authors.initials: RP
authors.lastname: Pangrazi
authors.forename: Susan V
authors.initials: SV
authors.lastname: Graser
authors.forename: Anders
authors.initials: A
authors.lastname: Raustorp
authors.forename: L M
authors.initials: LM
authors.lastname: Tomson
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Cuddihy
mesh_terms: D000203:Activities of Daily Living; D001315:Australia; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory; D012016:Reference Values; D012737:Sex Factors; D013548:Sweden; D014481:United States; D016138:Walking