title: Physical activity levels among children attending after-school programs.
abstract: OBJECTIVE
  To describe the physical activity (PA) levels of children attending after-school programs, 2) examine PA levels in specific after-school sessions and activity contexts, and 3) evaluate after-school PA differences in groups defined by sex and weight status.
  
  
  METHODS
  One hundred forty-seven students in grades 3-6 (mean age: 10.1 +/- 0.7, 54.4% male, 16.5 % overweight (OW), 22.8% at-risk for OW) from seven after-school programs in the midwestern United States wore Actigraph GT1M accelerometers for the duration of their attendance to the program. PA was objectively assessed on six occasions during an academic year (three fall and three spring). Stored activity counts were uploaded to a customized data-reduction program to determine minutes of sedentary (SED), light (LPA), moderate (MPA), vigorous (VPA), and moderate-to-vigorous (MVPA) physical activity. Time spent in each intensity category was calculated for the duration of program attendance, as well as specific after-school sessions (e.g., free play, snack time).
  
  
  RESULTS
  On average, participants exhibited 42.6 min of SED, 40.8 min of LPA, 13.4 min of MPA, and 5.3 min of VPA. The average accumulation of MVPA was 20.3 min. Boys exhibited higher levels of MPA, VPA, and MVPA, and lower levels of SED and LPA, than girls. OW and at-risk-for-OW students exhibited significantly less VPA than nonoverweight students, but similar levels of LPA, MPA, and MVPA. MVPA levels were significantly higher during free-play activity sessions than during organized or structured activity sessions.
  
  
  CONCLUSIONS
  After-school programs seem to be an important contributor to the PA of attending children. Nevertheless, ample room for improvement exists by making better use of existing time devoted to physical activity.
authors.affiliation: Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97333, USA. stewart.trost@oregonstate.edu
authors.forename: Stewart G
authors.initials: SG
authors.lastname: Trost
authors.forename: Richard R
authors.initials: RR
authors.lastname: Rosenkranz
authors.forename: David
authors.initials: D
authors.lastname: Dzewaltowski
mesh_terms: D000054:Acceleration; D000886:Anthropometry; D015992:Body Mass Index; D002648:Child; D002669:Child Welfare; D015444:Exercise / Q000502:physiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D009043:Motor Activity; D012572:School Health Services; D012574:Schools; D013997:Time Factors