title: Physically active academic lessons and time on task: the moderating effect of body mass index.
abstract: Physically active classroom lessons have been found to increase on-task behavior in children. Given that physical activity has been associated with an increased time on task (TOT) and that overweight children take fewer steps than normal weight children do, it was expected that benefits of the physical activity would differentially impact those children of higher weight status.
  
  
  OBJECTIVE
  To examine the effects of a physically active classroom lesson and body mass index (BMI) category on TOT in a sample of elementary-aged children (N = 97).
  
  
  METHODS
  Behavior was assessed through direct observations before and after a physically active classroom lesson and before and after a traditional inactive classroom lesson. TOT was calculated through momentary time sampling for each student by dividing the number of on-task observations by the total number of observations per student (interrater reliability = 94%).
  
  
  RESULTS
  TOT decreased significantly from before to after the lesson for all BMI categories in the inactive control condition, with no change for the active condition. Post hoc analyses found a significant linear effect for the reduction in TOT with each level of BMI in the inactive condition, with the greatest magnitude of effect for the overweight group.
  
  
  CONCLUSIONS
  Physically active classroom lessons provide a buffer to prevent the steep reduction in TOT experienced after a period of inactivity in all children, especially those who are overweight.
authors.affiliation: Exercise and Sport Psychology Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Grieco
authors.forename: Esbelle M
authors.initials: EM
authors.lastname: Jowers
authors.forename: John B
authors.initials: JB
authors.lastname: Bartholomew
mesh_terms: D000704:Analysis of Variance; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D050177:Overweight; D011897:Random Allocation; D012574:Schools; D016037:Single-Blind Method; D013647:Task Performance and Analysis; D013663:Teaching / Q000379:methods*; D013997:Time Factors