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Journal of Obesity
Volume 2011 (2011), Article ID 398918, 8 pages
Research Article

Utility of Accelerometers to Measure Physical Activity in Children Attending an Obesity Treatment Intervention

1Health Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
2Biomolecular and Sport Sciences, Coventry University, Coventry CV1 5FB, UK

Received 26 May 2010; Revised 12 August 2010; Accepted 13 September 2010

Academic Editor: James A. Levine

Copyright © 2011 Wendy Robertson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objectives. To investigate the use of accelerometers to monitor change in physical activity in a childhood obesity treatment intervention. Methods. 28 children aged 7–13 taking part in “Families for Health” were asked to wear an accelerometer (Actigraph) for 7-days, and complete an accompanying activity diary, at baseline, 3-months and 9-months. Interviews with 12 parents asked about research measurements. Results. Over 90% of children provided 4 days of accelerometer data, and around half of children provided 7 days. Adequately completed diaries were collected from 60% of children. Children partake in a wide range of physical activity which uniaxial monitors may undermonitor (cycling, nonmotorised scootering) or overmonitor (trampolining). Two different cutoffs (4 METS or 3200 counts ) for minutes spent in moderate and vigorous physical activity (MVPA) yielded very different results, although reached the same conclusion regarding a lack of change in MVPA after the intervention. Some children were unwilling to wear accelerometers at school and during sport because they felt they put them at risk of stigma and bullying. Conclusion. Accelerometers are acceptable to a majority of children, although their use at school is problematic for some, but they may underestimate children's physical activity.