title: Mapping the social and physical contexts of physical activity across adolescence using ecological momentary assessment.
abstract: BACKGROUND
  Research has sought to understand how environmental factors influence adolescent physical activity, yet little is known about where and with whom adolescents are physically active.
  
  
  OBJECTIVE
  This study used electronic ecological momentary assessment (e.EMA) to map the social and physical contexts of exercise and walking across adolescence. Differences in physical activity contexts by gender, grade in school, day of the week, and season were examined.
  
  
  METHODS
  Twice a year between 9th and 12th grade, 502 adolescents (51% female) of mixed ethnicity (55% White) participated in 4-day e.EMA intervals (Thursday-Sunday) where their primary activity (e.g., exercise, TV, homework), social company (e.g., friends, family, class), and physical location (e.g., home, school, outdoors) were assessed every 30 (+/-10) min during waking hours.
  
  
  RESULTS
  Overall, greater proportions of exercise and walking were reported with friends, outdoors, and at school. However, boys were more likely to report exercising and walking in outdoor locations than girls. Exercising with classmates, family, and at school decreased across high school. Walking with family, friends, and outdoors also decreased. On weekdays compared to weekends, students reported a greater proportion of their exercise and walking at school. Students were more likely to report exercising and walking outdoors in the fall and the spring than in the winter.
  
  
  CONCLUSIONS
  e.EMA showed that the social and physical contexts of adolescent exercise and walking vary as a function of gender, grade in school, day of the week, and season. Understanding the contexts of physical activity during the high school years can be helpful in designing interventions during adolescence.
authors.affiliation: Department of Psychology and Social Behavior, University of California, Irvine 92697, USA.
authors.forename: Genevieve Fridlund
authors.initials: GF
authors.lastname: Dunton
authors.forename: Carol K
authors.initials: CK
authors.lastname: Whalen
authors.forename: Larry D
authors.initials: LD
authors.lastname: Jamner
authors.forename: Josh N
authors.initials: JN
authors.lastname: Floro
mesh_terms: D000293:Adolescent; D000339:Affect; D000367:Age Factors; D002140:California; D034201:Computers, Handheld; D003430:Cross-Sectional Studies; D015444:Exercise / Q000523:psychology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008499:Medical Records; D012621:Seasons; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology / Q000523:psychology; D012931:Social Environment; D013334:Students / Q000523:psychology / Q000706:statistics & numerical data; D013997:Time Factors; D016138:Walking / Q000523:psychology