title: Effect of Physically Active Academic Lessons on Body Mass Index and Physical Fitness in Primary School Children.
abstract: BACKGROUND
  Preventing overweight and improving physical fitness in primary school children is a worldwide challenge, and physically active intervention programs usually come with the cost of academic instruction time. This study aimed to investigate effects of physically active academic lessons on body mass index (BMI) and physical fitness in primary school children.
  
  
  METHODS
  Dutch children attending second- or third-grade class from 12 primary schools (N = 376; 8.1 ± 0.7 years) were randomly assigned to a 22-week intervention program or to the control group. In addition to measuring BMI before and after the intervention, physical fitness was measured with 5 items of the Eurofit test battery, measuring cardiovascular and muscular fitness.
  
  
  RESULTS
  Multilevel analysis showed a significant interaction effect between condition (intervention vs control) and grade (B = -0.47; p < .05). For third-grade children, BMI of the intervention group did not change significantly during the intervention period, whereas a significant increase was found in the control group. No significant main or interaction effects were found for cardiovascular or muscular fitness.
  
  
  CONCLUSIONS
  The current physically active academic lessons had positive effects on BMI in third-grade children, but had no effects on cardiovascular and muscular fitness.
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713 AV Groningen, the Netherlands. j.w.de.greeff@umcg.nl.
authors.forename: Johannes W
authors.initials: JW
authors.lastname: de Greeff
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713 AV Groningen, the Netherlands. e.hartman@umcg.nl.
authors.forename: Esther
authors.initials: E
authors.lastname: Hartman
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Antonius Deusinglaan 1, 9713 AV Groningen, the Netherlands. m.j.mullender-wijsma@umcg.nl.
authors.forename: Marijke J
authors.initials: MJ
authors.lastname: Mullender-Wijnsma
authors.affiliation: University of Groningen, Groningen Institute for Educational Research, Grote Rozenstraat 3, 9712 TG Groningen, the Netherlands. r.j.bosker@rug.nl.
authors.forename: Roel J
authors.initials: RJ
authors.lastname: Bosker
authors.affiliation: University of Groningen, Groningen Institute for Educational Research, Grote Rozenstraat 3, 9712 TG Groningen, the Netherlands. s.doolaard@rug.nl.
authors.forename: Simone
authors.initials: S
authors.lastname: Doolaard
authors.affiliation: University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, P.O. Box 196, 9700 AD Groningen, the Netherlands. c.visscher@umcg.nl.
authors.forename: Chris
authors.initials: C
authors.lastname: Visscher
mesh_terms: D015992:Body Mass Index; D002648:Child; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D050177:Overweight / Q000517:prevention & control; D063766:Pediatric Obesity / Q000517:prevention & control; D010809:Physical Fitness; D012574:Schools / Q000458:organization & administration*
keywords: elementary school children; exercise intervention; physical activity; randomized controlled trial