title: A systematic review of the prevalence of sedentary behavior during the after-school period among children aged 5-18 years.
abstract: BACKGROUND
  Independent of physical activity levels, youth sedentary behaviors (SB) have negative health outcomes. SB prevalence estimates during discretionary periods of the day (e.g., after-school), inform the need for targeted period-specific interventions. This systematic review aimed to determine children's and adolescents' SB prevalence during the after-school period.
  
  
  METHODS
  A computerized search was conducted in October 2015 (analysed November 2015). Inclusion criteria were: published in a peer-reviewed English journal; participants aged 5-18 years; measured overall after-school sedentary time (ST) objectively, and/or specific after-school SBs (e.g., TV viewing) objectively or subjectively; and provided the percentage of the after-school period spent in ST/SB or duration of behavior and period to calculate this. Where possible, findings were analyzed by location (e.g., after-school care/'other' locations). The PRISMA guidelines were followed.
  
  
  RESULTS
  Twenty-nine studies were included: 24 included children (≤12 years), four assessed adolescents (>12 years) and one included both; 20 assessed ST and nine assessed SB. On average, children spent 41% and 51% of the after-school period in ST when at after-school care and other locations respectively. Adolescents spent 57% of the after-school period in ST. SBs that children and adolescents perform include: TV viewing (20% of the period), non-screen based SB (including homework; 20%), screen-based SB (including TV viewing; 18%), homework/academics (13%), motorised transport (12%), social SB (9%), and screen-based SB (excluding TV viewing; 6%).
  
  
  CONCLUSIONS
  Children spent up to half of the after-school period in ST and this is higher among adolescents. A variety of screen- and non-screen based SBs are performed after school, providing key targets for interventions.
  
  
  BACKGROUND
  PROSPERO registration number CRD42015010437.
authors.affiliation: Institute for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Highway, Burwood, VIC, Australia. lauren.arundell@deakin.edu.au.
authors.forename: Lauren
authors.initials: L
authors.lastname: Arundell
authors.affiliation: Institute for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Highway, Burwood, VIC, Australia.
authors.forename: Elly
authors.initials: E
authors.lastname: Fletcher
authors.affiliation: Institute for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Highway, Burwood, VIC, Australia.
authors.forename: Jo
authors.initials: J
authors.lastname: Salmon
authors.affiliation: Institute for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Highway, Burwood, VIC, Australia.
authors.forename: Jenny
authors.initials: J
authors.lastname: Veitch
authors.affiliation: Institute for Physical Activity and Nutrition Research, Deakin University, 221 Burwood Highway, Burwood, VIC, Australia.
authors.forename: Trina
authors.initials: T
authors.lastname: Hinkley
mesh_terms: D000293:Adolescent; D002648:Child; D015444:Exercise; D015438:Health Behavior; D006801:Humans; D012574:Schools; D057185:Sedentary Behavior; D013690:Television
keywords: Adolescents; After-school hours; Children; Prevalence; Sedentary behavior