title: Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis.
abstract: The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions.
  
  
  
  A systematic search was performed to identify randomized controlled trials targeting adolescents (age: ≥10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored.
  
  
  
  Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects.
  
  
  
  Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols.
authors.affiliation: Division of Training and Movement Sciences, University of Potsdam, Potsdam, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Borde
authors.affiliation: Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: J J
authors.initials: JJ
authors.lastname: Smith
authors.affiliation: Hunter New England Population Health, Wallsend, NSW, Australia.|School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia.|Hunter Medical Research Institute, Lambton, NSW, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Sutherland
authors.affiliation: Hunter New England Population Health, Wallsend, NSW, Australia.|School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia.|Hunter Medical Research Institute, Lambton, NSW, Australia.
authors.forename: N
authors.initials: N
authors.lastname: Nathan
authors.affiliation: Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: D R
authors.initials: DR
authors.lastname: Lubans
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena; D004032:Diet; D015444:Exercise / Q000523:psychology; D006801:Humans; D009043:Motor Activity; D063766:Pediatric Obesity / Q000453:epidemiology / Q000517:prevention & control*; D015397:Program Evaluation; D016032:Randomized Controlled Trials as Topic; D012572:School Health Services
keywords: Accelerometer; physical activity; school; youth