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Comparison of two methods to assess physical activity prevalence in children: an observational study using a nationally representative sample of Scottish children aged 10–11 years
  1. Paul McCrorie,
  2. Rich Mitchell,
  3. Anne Ellaway
  1. MRC/CSO Social & Public Health Sciences Unit, University of Glasgow, Glasgow, UK
  1. Correspondence to Dr Paul McCrorie; paul.mccrorie{at}


Objectives To describe the objectively measured levels of physical activity (PA) and sedentary time in a nationally representative sample of 10–11-year-old children, and compare adherence estimates to the UK PA guidelines using two approaches to assessing prevalence.

Design Nationally representative longitudinal cohort study.

Setting Scotland wide in partnership with the Growing up in Scotland (GUS) study. Data collection took place between May 2015 and May 2016.

Participants The parents of 2402 GUS children were approached and 2162 consented to contact. Consenting children (n=1096) wore accelerometers for 8 consecutive days and 774 participants (427 girls, 357 boys) met inclusion criteria.

Primary and secondary outcome measures Total PA (counts per minute, cpm); time spent sedentary and in moderate-to-vigorous PA (MVPA); proportion of children with ≥60 min MVPA on each day of wear (daily approach); proportion of children with ≥60 min of MVPA on average across days of wear (average approach)—presented across boys and girls, index of multiple deprivation and season.

Results Mean PA level was 648 cpm (95% CI, 627 to 670). Children spent 7.5 hours (7.4–7.6) sedentary/day and 72.6 min (70.0–75.3) in MVPA/day. 11% (daily) and 68% (average) of children achieved the recommended levels of PA (P<0.05 for difference); a greater proportion of boys met the guidelines (12.5% vs 9.8%, NS; 75.9% vs 59.5%, P<0.001); guideline prevalence exhibited seasonal variation. No significant socioeconomic patterning existed across any outcome measure.

Conclusions PA estimates are significantly influenced by the analytical method used to assess prevalence. This could have a substantial impact on the evaluation of interventions, policy objectives and public health investment. Existing guidelines, which focus on daily PA only may not further our understandings about the underlying construct itself. Gender differences exist within this age-group, suggesting greater investment, with particular consideration of seasonality, is needed for targeted intervention work in younger children.

  • Exercise
  • Child
  • Prevalence

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  • Contributors PM and AE ran the data collection process, and PM led on data processing and data analysis and drafted the article. RM and AE assisted with statistical analysis and interpretation of the data, and RM contributed to the graphical presentation of the results. AE and RM critically revised the article and all authors signed off the final draft.

  • Funding This work was supported by the Medical Research Council [grant number MC_UU_12017/10] and Chief Scientist Office [grant number SPHSU10]; and the Scottish Government [grant number SR/SC 17/04/2012].

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Ethics Committee of College of Social Sciences, University of Glasgow (CSS ref: 400140067).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement We are committed to maximising the use of SPACES study data to advance knowledge to improve young people’s health and welcome proposals for collaborative projects and data sharing. Our data sharing policy follows that of the Medical Research Council and aims to balance making data as widely and freely available as possible with safeguarding the privacy of participants, protecting confidential data, and maintaining the reputation of the study. please contact Prof Anne Ellaway ( for further information.

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