Arch Dis Child 92:963-969 doi:10.1136/adc.2006.112136
  • Original article

Objective measurement of levels and patterns of physical activity

Open Access
  1. Chris J Riddoch1,
  2. Calum Mattocks2,
  3. Kevin Deere2,
  4. Jo Saunders2,
  5. Jo Kirkby2,
  6. Kate Tilling2,
  7. Sam D Leary2,
  8. Steven N Blair3,
  9. Andy R Ness2
  1. 1
    Sport and Exercise Science, School for Health, University of Bath, Bath, UK
  2. 2
    Department of Social Medicine, University of Bristol, Bristol, UK
  3. 3
    University of South Carolina, Columbia, South Carolina, USA
  1. Professor Chris Riddoch, Sport and Exercise Science, School for Health, University of Bath, Bath BA2 7AY, UK; cjr27{at}
  • Accepted 29 June 2007
  • Published Online First 13 September 2007


Objective: To measure the levels and patterns of physical activity, using accelerometers, of 11-year-old children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC).

Design: Cross-sectional analysis.

Setting: ALSPAC is a birth cohort study located in the former county of Avon, in the southwest of England. This study used data collected when the children were 11 years old.

Participants: 5595 children (2662 boys, 2933 girls). The children are the offspring of women recruited to a birth cohort study during 1991–2. The median age (95% CI) of the children is now 11.8 (11.6 to 11.9) years.

Methods: Physical activity was measured over a maximum of 7 consecutive days using the MTI Actigraph accelerometer.

Main outcome measures: Level and pattern of physical activity.

Results: The median physical activity level was 580 counts/min. Boys were more active than girls (median (IQR) 644 (528–772) counts/min vs 529 (444–638) counts/min, respectively). Only 2.5% (95% CI 2.1% to 2.9%) of children (boys 5.1% (95% CI 4.3% to 6.0%), girls 0.4% (95% CI 0.2% to 0.7%) met current internationally recognised recommendations for physical activity. Children were most active in summer and least active in winter (difference = 108 counts/min). Both the mother and partner’s education level were inversely associated with activity level (p for trend <0.001 (both mother and partner)). The association was lost for mother’s education (p for trend = 0.07) and attenuated for partner’s education (p for trend = 0.02), after adjustment for age, sex, season, maternal age and social class.

Conclusions: A large majority of children are insufficiently active, according to current recommended levels for health.


  • Funding: The UK Medical Research Council, the Wellcome Trust and the University of Bristol provide core support for ALSPAC. This research was specifically funded by a grant from National Heart, Lung and Blood Institute (R01 HL071248-01A).The funding source had no input to the study design, apart from changes required by external peer reviewers.

  • Competing interests: None.

  • Abbreviations:
    Avon Longitudinal Study of Parents and Children
    body mass index
    International Task Force
    moderate to vigorous physical activity