title: Youth destinations associated with objective measures of physical activity in adolescents.
abstract: OBJECTIVE
  Limited availability of desirable destinations within walkable distances and unsuitable weather may adversely affect physical activity among adolescents on weekends. This study examines evidence for associations between objective measures of local environment and physical activity levels of adolescents.
  
  
  METHODS
  Students (n=152, 59% male; mean age, 13.7 years) from 10 neighborhoods with schools in four communities wore TriTrac-R3D accelerometers recording physical movements on weekends. Minute-by-minute data were summed over 15-minute intervals providing estimates of proportion of time spent in moderate and vigorous physical activity (MVPA) and (log) mean physical activity levels on weekends (n=7,506 intervals). Objective measures of neighborhood characteristics were calculated using geographic information systems including average daily traffic, housing density, open space, and density of employees per square kilometer in youth destinations. Linear mixed models were fit examining associations between neighborhood environmental variables and accelerometer measures of physical activity, controlling for time, day, age, body mass index, gender of respondent, race/ethnicity, precipitation, and temperature deviation.
  
  
  RESULTS
  On weekends, the presence of greater densities of employees in neighborhood destinations serving youth (beta=3.96, p=0.050) was directly associated with MVPA, independent of student characteristics.
  
  
  CONCLUSIONS
  Young people attending schools in neighborhoods characterized by greater densities of employees in destinations for youth are more physically active on weekends. Compared with neighborhoods with lower densities, attending a school in neighborhoods with higher densities of employees in potential destinations for youth may contribute to participation in an additional 30 minutes of MVPA per day on weekends.
authors.affiliation: Department of Society, Human Development and Health, Harvard School of Public Health, Boston, Massachusetts 02115, USA. acradock@hsph.harvard.edu
authors.forename: Angie L
authors.initials: AL
authors.lastname: Cradock
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Melly
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Allen
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Morris
authors.forename: Steven L
authors.initials: SL
authors.lastname: Gortmaker
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D001900:Boston; D004779:Environment Design; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods; D009043:Motor Activity; D012111:Residence Characteristics; D016138:Walking
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