Background: An accurate description of physical activity (PA) at school is required for appropriate health interventions. We examined PA patterns in children, and identified the time periods that influenced them.
Methods: Forty students in five Japanese primary schools were asked to wear triaxial accelerometers for ≥7 days. We obtained coefficients of variance (CV) at 15 min intervals, and conducted factor analysis of the school periods. A questionnaire was used to investigate where students spent time before school, and during recess.
Results: The amount of PA, and its CV were higher around 8 a.m. (before-school period), 10 a.m. (morning recess), 1 p.m. (lunch recess), and 4 p.m. (commuting home from school). Moderate-vigorous PA (MVPA; ≥3.0 metabolic equivalent units [MET]) was highest during lunch recess and the after-school period (12.9 ± 7.4 min and 12.6 ± 6.2 min, respectively). The percentage of MVPA time was high (>15%) in the before-school period and morning and lunch recesses, but low (10%) in the after-school period. On factor analysis there were differences in PA patterns between the school period and the after-school period. The students who spent their time in the playground logged more MVPA time and less sedentary time (≤1.5 MET) than those who did not spend their time in the playground.
Conclusion: Activities before school, and in the morning and lunch recesses influenced daily PA, and were different from after-school PA. Close attention to these periods may help in defining PA parameters during free time at school for PA interventions in children.
Keywords: factor analysis; physical activity; primary school; recess; time segment.
© 2018 Japan Pediatric Society.