PURPOSE: The purpose of the present study was to examine the effects of a cluster-randomised, controlled school-based intervention (the STOPP-study) on objectively measured sedentary time, time spent in light intensity activity and in moderate to vigorous physical activity (MVPA).
METHODS: A total of 1538 children in grades 1-4 from ten selected schools in Stockholm county area were included. Schools were randomised as intervention (n=5) or control (n=5). Physical activity was aimed to increase by 30 min -1day during school time and sedentary behavior was restricted during after school care time. Physical activity was measured by accelerometry. Percentage of time spent sedentary (below 1.5 METs), in light (between 1.5 and 3 METs), and in MVPA (above 3 METs) were primary outcome variables.
RESULTS: Adjusted for age, gender and calendar year, children in intervention schools spent less time sedentary, compared to children in control schools (32.3% vs. 33.4% of registered time, P=0.03) and more time in MVPA (28.5% vs. 27.6%, P=0.05). Children in the intervention group spent more time in MVPA (37.2% vs. 34.9%, P=0.002) and less time sedentary (22.0% vs. 24.3%, P<0.001) during after school care time. Normal weight and overweight children in intervention schools spent more time in MVPA and less time sedentary during after school care time compared to children in the control schools. Overweight children in the intervention group spent more time in light intensity activity during evening time. There was a trend for less sedentary activities in overweight intervention children during evening time. The results were attenuated after adjustment for the sampling variation between schools.
CONCLUSIONS: There were indications of differences between intervention and control groups in time spent sedentary and in MVPA among normal weight and overweight children. Although differences were not statistically significant after adjustment for the cluster effect, the present paper provides argument for school-based interventions in order to decrease sedentary behaviour and increase physical activity.
2011. Vol. 43, suppl 15, 24-24 p.
ACSM 58th Annual Meeting & 2nd World Congress on Exercise is Medicine. May 31-June 4, 2011, Denver, Colorado