Introduction: Sedentary behavior in children is associated with poor health whilst moderate/vigorous activity is associated with better health. The school setting may be an opportunity to reduce sedentariness and enhance physical activity, yet concerns have been raised that children may be more sedentary at school. This paper examined activity patterns, including both sedentary time and time in health enhancing physical activity, in children across their typical week.

Methods: Sixty-six 10–12 year old children were recruited from 48 schools in the Perth metropolitan area as part of a randomized controlled study (Australia and New Zealand Clinical Trials Registry ACTRN 12609000279224) investigating the effects of electronic games on physical activity. The data for this paper come from their baseline assessment, which all occurred during school term time. Children wore an Actical accelerometer on their hip for one week. Time spent in sedentary, light, moderate and vigorous physical activity was assessed. School day and weekend day activity patterns were examined along with activity patterns both in (school time) and out of school (non-school-time) on school days.

Results: Valid (at least 4 days) accelerometer data were available on 53 children (28 girls). The average time of accelerometer recording per day was 822 ± 71 minutes (13.7 hours). Accumulated time in sedentary behavior was similar on school days and weekend days (mean [SD]: 64.4%[5.3] vs 64.9%[9.0], p = 0.686). Children were more likely to reach physical activity guidelines on school days than at the weekend (47.7% v 22.2%, p < 0.001) and spend more time in brief–less than 5 minutes–bursts of activity of any intensity (35.3%[5.1] vs 32.6%[6.9], p = 0.002). However, children spent a higher proportion of time in sedentary behavior (66.8%[7.3] vs 62.4%[5.2], p < 0.001), and significantly more time in extended sedentariness–sedentary for more than thirty minutes or more (75.6mins[45.8] vs 45.0 mins[26.8], p < 0.002)–within school time compared to non-school time.

Discussion: Children spent a considerable proportion of their school or non-school day in sedentary behavior, and routinely spent over two hours of each day in extended sedentary behavior. School should be a place where children learn healthful habits, and whilst it appears to be associated with better moderate/vigorous physical activity exposure it was associated with poorer extended sedentary exposure. Increasing moderate/vigorous physical activity and reducing time spent in sedentary behavior both in and out of school remains an important challenge.