title: School-based randomized controlled trial of a physical activity intervention among adolescents.
abstract: OBJECTIVE
  To evaluate the effects of a middle school physical activity intervention, new in combining an environmental and computer tailored component; and to evaluate the effects of parental involvement.
  
  
  METHODS
  A clustered randomized controlled design was used. A random sample of 15 schools with 7th and 8th graders was randomly assigned to one of three conditions: (a) intervention with parental support, (b) intervention alone, and (c) control group. The intervention was new in combining environmental strategies with computer-tailored feedback to increase levels of moderate to vigorous physical activity. The intervention was implemented by the school staff. Physical activity was measured through a questionnaire in the total sample and with accelerometers in a sub sample of adolescents.
  
  
  RESULTS
  The intervention with parental support led to an increase in self-reported school-related physical activity of, on average, 6.4 minutes per day (p < or = .05, d = .40). Physical activity of light intensity measured with accelerometers decreased with, on average, 36 minutes per day as a result of the intervention with parental support (p < or = .05, d = .54). Physical activity of moderate to vigorous intensity measured with accelerometers significantly increased with on average 4 minutes per day in the intervention group with parental support, while it decreased with almost 7 minutes per day in the control group (p < or = .05, d = .46).
  
  
  CONCLUSIONS
  The physical activity intervention, implemented by the school staff, resulted in enhanced physical activity behaviors in both middle school boys and girls. The combination of environmental approaches with computer-tailored interventions seemed promising.
authors.affiliation: Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium. Leen.Haerens@UGent.be
authors.forename: Leen
authors.initials: L
authors.lastname: Haerens
authors.forename: Ilse
authors.initials: I
authors.lastname: De Bourdeaudhuij
authors.forename: Lea
authors.initials: L
authors.lastname: Maes
authors.forename: Greet
authors.initials: G
authors.lastname: Cardon
authors.forename: Benedicte
authors.initials: B
authors.lastname: Deforche
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D005260:Female; D006266:Health Education / Q000379:methods*; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008019:Life Style; D008297:Male; D009043:Motor Activity; D010287:Parent-Child Relations; D010806:Physical Education and Training / Q000379:methods; D012572:School Health Services