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Background: Physical activity and sedentary behaviour among children should be measured accurately in order to investigate their relationship with health. Accelerometry provides objective and accurate measurement of body movement, which can be converted to meaningful behavioural outcomes. The aim of this study was to evaluate the best evidence for the decisions on data collection and data processing with accelerometers among children resulting in a standardized protocol for use in the participating countries. Methods/Design: This cross-sectional accelerometer study was conducted as part of the European ENERGY-project that aimed to produce an obesity prevention intervention among schoolchildren. Five countries, namely Belgium, Greece, Hungary, Switzerland and the Netherlands participated in the accelerometer study. We used three different Actigraph models-Actitrainers (triaxial), GT3Xs and GT1Ms. Children wore the device for six consecutive days including two weekend days. We selected an epoch length of 15 seconds. Accelerometers were placed at children's waist at the right side of the body in an elastic belt. In total, 1082 children participated in the study (mean age = 11.7 ± 0.75 y, 51% girls). Non-wearing time was calculated as periods of more than 20 minutes of consecutive zero counts. The minimum daily wearing time was set to 10 hours for weekdays and 8 hours for weekend days. The inclusion criterion for further analysis was having at least three valid weekdays and one valid weekend day. We selected a cut-point (count per minute (cpm)) of <100 cpm for sedentary behaviour, <3000 cpm for light, <5200 cpm for moderate, and >5200 cpm for vigorous physical activity. We also created time filters for school-time during data cleaning in order to explore school-time physical activity and sedentary behaviour patterns in particular. Discussion: This paper describes the decisions for data collection and processing. Use of standardized protocols would ease future use of accelerometry and the comparability of results between studies. [ABSTRACT FROM AUTHOR]

Objectives: This study aims to describe the time devoted to sedentary and physical activities at school in five European countries and to examine differences according to country, sex, ethnicity, parental education and weight status., Design: cross-European cross-sectional survey., Methods: Primary schoolchildren (n=1025) aged 10-12 years in Belgium, Greece, Hungary, the Netherlands, and Switzerland wore accelerometers for at least six consecutive days. Only weekdays were used for this study to calculate the percentages of school-time spent in sedentary activities and moderate to vigorous intensity activity. Trained research assistants measured height and weight. Sex and date of birth were self-reported by the child and parental education and ethnicity were parent-reported., Results: European schoolchildren spent on average 65% of their time at school in sedentary activities and 5% on moderate to vigorous intensity activities, with small differences between countries. Girls spent a significant larger amount of school-time in sedentary activities (67%) than boys (63%; p<0.0001), and spent less time in moderate to vigorous intensity activities (4% versus 5%; p<0.001). Overweight children spent significantly less time in moderate to vigorous intensity activities (4%) than normal weight children (5%,p < 0.01) [corrected]. Parental education or ethnicity were not associated with time spent in sedentary or physical activities., Conclusions: European schoolchildren spend a small amount of their school-time in moderate to vigorous intensity activities and a large amount in sedentary activities, with small but significant differences across countries. Future interventions should target more physical activities and less sedentary time at school particularly in girls., (Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)