Using the ActivPAL Monitor to Quantify Time Spent Sitting, Standing and Stepping at School: A One-day Snapshot

Abstract

Background: Our understanding of the amount of time children spend sitting, standing and stepping during a typical school day is limited. The ActivPAL monitor, which can differentiate between sitting and standing, was used in this study to objectively assess free-living activities in children. Aims: The main purpose was to objectively quantify the time children spend sitting, standing and stepping in a typical school day. A secondary purpose was to compare the ActivPAL monitor step counts with those obtained from Actical accelerometers. Study Design: Pilot observational study. Place and Duration of Study: Elementary school in Auckland, New Zealand, July 2010. Methodology: A total of 78 elementary school children (age 8.4±1.4 years; mean ± SD) participated in the study for one school day in July 2010. Within-day differences in the proportions of time spent sitting, standing and stepping were assessed using ANOVA. The effect of sex and age on mean scores was also evaluated, using independent-samples t-tests and one-way between-groups ANOVA respectively. Bland and Altman analyses were used to estimate the agreement in step counts between devices. Results: From an average of 303±6 minutes, children spent 170±35 min (56%) sitting, 77±24 min (25%) standing, and 56±19 min (18%) stepping. Most of children’s sitting time occurred in class (149±10 min; 49%). Boys and girls accumulated similar proportions of sitting, standing and stepping. On average, 33% more steps recorded by the Actical accelerometer compared to the ActivPAL. Conclusion: Our results suggest that children spend over half of their time at school sitting. Furthermore, the ActivPAL monitor steps are not equivalent to the Actical accelerometer steps.