title: The impact of school-time activity on total physical activity: the activitystat hypothesis (EarlyBird 46).
abstract: OBJECTIVE
  To explore the activitystat hypothesis in primary school children by asking whether more physical activity (PA) in school time is compensated for by less PA at other times.
  
  
  METHODS
  Observational, repeated measures (four consecutive occasions over a 12-month period).
  
  
  METHODS
  South-west England.
  
  
  METHODS
  A total of 206 children (115 boys, aged 8-10 years) from 3 primary schools (S1, S2 and S3), which recorded large differences in PA during school time.
  
  
  METHODS
  Total PA (TPA) and its moderate-and-vigorous component were recorded weekly by accelerometry, in school and out of school, and adjusted for local daily rainfall and daylight hours. Habitual PA was assessed by linear mixed-effects modelling on repeated measures.
  
  
  RESULTS
  S1 children recorded 64% more in-school PA, but S2 and S3 children compensated with correspondingly more out-of-school PA, so that TPA between the three schools was no different: 35.6 (34.3-36.9), 37.3 (36.0-38.6) and 36.2 (34.9-37.5) Units, respectively (P=0.38).
  
  
  CONCLUSIONS
  The PA of children seems to compensate in such a way that more activity at one time is met with less activity at another. The failure of PA programmes to reduce childhood obesity could be attributable to this compensation.
authors.affiliation: Department of Endocrinology and Metabolism, Peninsula College of Medicine and Dentistry, Plymouth Campus, University of Plymouth, Plymouth, U.K.
authors.forename: A E
authors.initials: AE
authors.lastname: Frémeaux
authors.forename: K M
authors.initials: KM
authors.lastname: Mallam
authors.forename: B S
authors.initials: BS
authors.lastname: Metcalf
authors.forename: J
authors.initials: J
authors.lastname: Hosking
authors.forename: L D
authors.initials: LD
authors.lastname: Voss
authors.forename: T J
authors.initials: TJ
authors.lastname: Wilkin
mesh_terms: D015992:Body Mass Index; D002648:Child; D015331:Cohort Studies; D002149:Energy Intake; D004734:Energy Metabolism; D004739:England / Q000453:epidemiology; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D007899:Leisure Activities; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000453:epidemiology / Q000517:prevention & control*; D010806:Physical Education and Training; D012574:Schools