Objective measurement of levels and patterns of physical activity
- Chris J Riddoch1,
- Calum Mattocks2,
- Kevin Deere2,
- Jo Saunders2,
- Jo Kirkby2,
- Kate Tilling2,
- Sam D Leary2,
- Steven N Blair3,
- Andy R Ness2
- 1 Sport and Exercise Science, School for Health, University of Bath, Bath, UK
- 2 Department of Social Medicine, University of Bristol, Bristol, UK
- 3 University of South Carolina, Columbia, South Carolina, USA
- Professor Chris Riddoch, Sport and Exercise Science, School for Health, University of Bath, Bath BA2 7AY, UK;
- 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.
- Avon Longitudinal Study of Parents and Children
- body mass index
- International Task Force
- moderate to vigorous physical activity