title: Sedentary behaviours among Australian adolescents.
abstract: OBJECTIVE
  To describe the prevalence and distribution (by demographic characteristics and body mass index [BMI] category) of sedentary behaviour among Australian adolescents aged 11-15 years.
  
  
  METHODS
  Cross-sectional representative population survey of school students (n = 2,750) in New South Wales, conducted in 2004. Students' self-reported time spent during a usual week in five categories of sedentary behaviour (small screen recreation [SSR], education, cultural, social and non-active travel). Height and weight were measured.
  
  
  RESULTS
  Grade 6, 8 and 10 students spent approximately 34 hours, 41 hours and 45 hours/week of their discretionary time, respectively, engaged in sedentary behaviour. Urban students and students from Asian-speaking backgrounds spent significantly more time sedentary than students from rural areas or other cultural backgrounds. SSR accounted for 60% and 54% of sedentary behaviour among primary and high school students, respectively. Overweight and obese students spent more time in SSR than healthy weight students. Out-of-school hours educational activities accounted for approximately 20% of sedentary behaviour and increased with age. Girls spent twice the time in social activities compared with boys. Time spent in cultural activities declined with age.
  
  
  CONCLUSIONS
  Sedentary behaviours among young people differ according to sex, age and cultural background. At least half of all time spent in sedentary behaviours was spent engaged in SSR. BMI was significantly associated with sedentary behaviour among some children, but not consistently across age groups.
  
  
  CONCLUSIONS
  A clear understanding of young people's patterns of sedentary behaviour is required to develop effective and sustainable intervention programs to promote healthy living.
authors.affiliation: NSW Centre for Overweight and Obesity, School of Public Health, University of Sydney, Camperdown, New South Wales. louiseh@health.usyd.edu.au
authors.forename: Louise L
authors.initials: LL
authors.lastname: Hardy
authors.forename: Timothy
authors.initials: T
authors.lastname: Dobbins
authors.forename: Michael L
authors.initials: ML
authors.lastname: Booth
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Denney-Wilson
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Okely
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007899:Leisure Activities; D016014:Linear Models; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D015995:Prevalence; D012111:Residence Characteristics; D012307:Risk Factors; D012923:Social Class