title: Longitudinal levels and bouts of objectively measured sedentary time among young Australian children in the HAPPY study.
abstract: OBJECTIVE
  To examine differences in sedentary time and bouts during and outside of childcare/school periods, and changes in sedentary time and bouts over 1-year among children who remained in childcare (childcare subsample) and among those who transitioned to school (school transition subsample).
  
  
  METHODS
  Longitudinal study.
  
  
  METHODS
  Results are based on 177 children aged 3-5 years at baseline from the Healthy Active Preschool and Primary Years study in Melbourne, Australia. Sedentary time and sedentary bouts (1-4, 5-9, ≥10min) for total days and during/outside of childcare/school on weekdays were accelerometer-derived at baseline (2008) and 1-year follow-up (2009), when 57% of participants had transitioned to school. Repeated-measures ANCOVAs adjusting for wear time were conducted.
  
  
  RESULTS
  Compared to the outside of childcare/school period, children in the school transition subsample spent more time (0.5min/day or 0.9% wear time) in ≥10min sedentary bouts at baseline, participated in 26 more min/day of sedentary time at follow-up, and all participants spent less time (2-16min/day or 2-3% of wear time) in 5-9min sedentary bouts at baseline and follow-up during the childcare/school period (P<0.05). Increases in sedentary time (34-54min/day or 2-3% wear time) and time spent in 1-4min sedentary bouts (18-29min/day or 1-2% of wear time) were observed from baseline to follow-up in both the total sample and school transition sub-sample, for total days and during the childcare/school period (P<0.05).
  
  
  CONCLUSIONS
  School transition was marked by increased sedentary time. School practices, policies, and environments to reduce sedentary time should be explored.
authors: University of Alberta, Faculty of Physical Education and Recreation, Canada. Electronic address: vlcarson@ualberta.ca.
authors: Valerie
authors: V
authors: Carson
authors: Deakin University, Center for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Australia.
authors: Jo
authors: J
authors: Salmon
authors: Deakin University, Center for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Australia.
authors: David
authors: D
authors: Crawford
authors: Deakin University, Center for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Australia.
authors: Trina
authors: T
authors: Hinkley
authors: Deakin University, Center for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Australia.
authors: Kylie D
authors: KD
authors: Hesketh
mesh_terms: D061725:Accelerometry; D001315:Australia; D002656:Child Day Care Centers; D002675:Child, Preschool; D015444:Exercise; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012574:Schools; D057185:Sedentary Behavior; D013997:Time Factors
keywords: Accelerometry; Preschool children; Sedentary lifestyle