title: Twelve-month effects of a playground intervention on children's morning and lunchtime recess physical activity levels.
abstract: BACKGROUND
  Recess is an opportunity for children to engage in daily physical activity. The aim of this study was to investigate the 12-month effects of a playground intervention on children's moderate-to-vigorous (MVPA) and vigorous physical activity (VPA) during morning and lunchtime recess.
  
  
  METHODS
  Four hundred and seventy children (232 boys, 238 girls) from 26 elementary schools participated in the study. Fifteen schools redesigned the playground environment using playground markings and physical structures. Eleven schools served as socioeconomic matched controls. Physical activity levels were quantified using heart rate and accelerometry at baseline, 6 months, and 12 months post-intervention. A 3-level (time, pupil, and school) multilevel analysis was used to determine the effects of the intervention across time on MVPA and VPA.
  
  
  RESULTS
  Positive yet nonsignificant intervention effects were found for MVPA and VPA during morning and lunchtime recess. Intervention children were more active during recess than control children. Interactions revealed that the intervention effect was stronger at 6 months than 12 months post-intervention.
  
  
  CONCLUSIONS
  A playground markings and physical structures intervention had a positive effect on intervention children's morning and lunchtime MVPA and VPA when assessed using heart rate and accelerometry, but this effect is strongest 6-months post-intervention and decreased between 6 months and 12 months.
authors.affiliation: Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.
authors.forename: Nicola D
authors.initials: ND
authors.lastname: Ridgers
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Fairclough
authors.forename: Gareth
authors.initials: G
authors.lastname: Stratton
mesh_terms: D000054:Acceleration; D056044:Actigraphy; D016022:Case-Control Studies; D002648:Child; D002669:Child Welfare; D016001:Confidence Intervals; D005260:Female; D015438:Health Behavior; D006339:Heart Rate; D006801:Humans; D008297:Male; D009043:Motor Activity; D015999:Multivariate Analysis; D010988:Play and Playthings; D011998:Recreation; D012574:Schools / Q000706:statistics & numerical data*; D013334:Students; D013997:Time Factors; D006113:United Kingdom