title: Physical activity and body mass index in grade 3, 7, and 11 Nova Scotia students.
abstract: OBJECTIVE
  This study examined the average time spent in moderate or more intense physical activities according to weight status in randomly selected Nova Scotia students.
  
  
  METHODS
  A total of 1653 students participated in this study: 575 in grade 3, 558 in grade 7, and 520 in grade 11. Physical activity was measured for seven consecutive days using MTI accelerometers. Activity counts were classified according to moderate (3-5.9 METs), hard (6-8.9 METs), and very hard (>9 METs) intensities. Height and weight were measured and body mass index (BMI) calculated. Centers for Disease Control and Prevention BMI criteria for age and sex were used to classify the students as normal weight (< or =85th percentile), at risk of overweight (>85th and < or =95th percentiles), and overweight (>95th percentile). ANOVA was used to compare the average time spent in moderate, hard, and very hard physical activities according to BMI status in boys and girls in grades 3, 7, and 11.
  
  
  RESULTS
  Although age and sex differences existed, there were no significant differences in the average time spent in moderate or more intense physical activities in the BMI groups.
  
  
  CONCLUSIONS
  Further research is warranted to elucidate the factors surrounding the relationship between physical activity and BMI in children and youths.
authors.affiliation: Department of Human Kinetics, St. Francis Xavier University, Antigonish, Nova Scotia, Canada. amthomps@stfx.ca
authors.forename: Angela M
authors.initials: AM
authors.lastname: Thompson
authors.forename: Philip D
authors.initials: PD
authors.lastname: Campagna
authors.forename: Laurene A
authors.initials: LA
authors.lastname: Rehman
authors.forename: René J L
authors.initials: RJ
authors.lastname: Murphy
authors.forename: Roy L
authors.initials: RL
authors.lastname: Rasmussen
authors.forename: Gary W
authors.initials: GW
authors.lastname: Ness
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D009674:Nova Scotia; D009765:Obesity / Q000209:etiology; D010809:Physical Fitness; D011998:Recreation; D012737:Sex Factors; D013334:Students