title: Increasing specificity of correlate research: exploring correlates of children's lunchtime and after-school physical activity.
abstract: BACKGROUND
  The lunchtime and after-school contexts are critical windows in a school day for children to be physically active. While numerous studies have investigated correlates of children's habitual physical activity, few have explored correlates of physical activity occurring at lunchtime and after-school from a social-ecological perspective. Exploring correlates that influence physical activity occurring in specific contexts can potentially improve the prediction and understanding of physical activity. Using a context-specific approach, this study investigated correlates of children's lunchtime and after-school physical activity.
  
  
  METHODS
  Cross-sectional data were collected from 423 South Australian children aged 10.0-13.9 years (200 boys; 223 girls) attending 10 different schools. Lunchtime and after-school physical activity was assessed using accelerometers. Correlates were assessed using purposely developed context-specific questionnaires. Correlated Component Regression analysis was conducted to derive correlates of context-specific physical activity and determine the variance explained by prediction equations.
  
  
  RESULTS
  The model of boys' lunchtime physical activity contained 6 correlates and explained 25% of the variance. For girls, the model explained 17% variance from 9 correlates. Enjoyment of walking during lunchtime was the strongest correlate for both boys and girls. Boys' and girls' after-school physical activity models explained 20% variance from 14 correlates and 7% variance from the single item correlate, "I do an organised sport or activity after-school because it gets you fit", respectively.
  
  
  CONCLUSIONS
  Increasing specificity of correlate research has enabled the identification of unique features of, and a more in-depth interpretation of, lunchtime and after-school physical activity behaviour and is a potential strategy for advancing the physical activity correlate research field. The findings of this study could be used to inform and tailor gender-specific public health messages and interventions for promoting lunchtime and after-school physical activity in children.
authors.affiliation: Exercise for Health and Human Performance Group, School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Stanley
authors.affiliation: Sport, Health and Physical Education Group, School of Education, Flinders University, Adelaide, South Australia, Australia.
authors.forename: Kate
authors.initials: K
authors.lastname: Ridley
authors.affiliation: Health and Use of Time Group, School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Olds
authors.affiliation: Exercise for Health and Human Performance Group, School of Health Sciences, University of South Australia, Adelaide, South Australia, Australia.
authors.forename: James
authors.initials: J
authors.lastname: Dollman
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D001315:Australia; D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D009043:Motor Activity; D010988:Play and Playthings; D012574:Schools; D011795:Surveys and Questionnaires