title: Using ecological momentary assessment to understand where and with whom adults' physical and sedentary activity occur.
abstract: OBJECTIVE
  This study used Ecological Momentary Assessment (EMA), a real-time self-report strategy, to describe the physical and social contexts of adults' physical activity and sedentary activity during their everyday lives and to determine whether these patterns and relationships differ for men and women.
  
  
  METHODS
  Data from 114 adults were collected through mobile phones across 4 days. Eight electronic EMA surveys were randomly prompted each day asking about current activities (e.g., physical or sedentary activity), physical and social contexts, and perceived outdoor environmental features (e.g., greenness/vegetation, safety, and traffic). All participants also wore accelerometers during this period to objectively measure moderate-to-vigorous physical activity (MVPA) and sedentary activity.
  
  
  RESULTS
  Home was the most common physical context for EMA-reported physical and sedentary activity. Most of these activities occurred when participants were alone. When alone, the most commonly EMA-reported physical activity and sedentary activity was walking and reading/using computer, respectively. When in outdoor home locations (e.g., yard and driveway) women demonstrated higher levels of MVPA, whereas men demonstrated higher levels of MVPA when in outdoor park settings (ps < .05). Men but not women demonstrated higher levels of MVPA in settings with a greater degree of perceived greenness and vegetation (p < .05).
  
  
  CONCLUSIONS
  The current study shows how EMA via mobile phones and accelerometers can be combined to offer an innovative approach to assess the contexts of adults' daily physical and sedentary activity. Future studies could consider utilizing this method in more representative samples to gather context-specific information to inform the development of physical activity interventions.
authors.affiliation: Institute for Health Promotion and Disease Prevention Research, Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA, yueliao@usc.edu.
authors.forename: Yue
authors.initials: Y
authors.lastname: Liao
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Intille
authors.forename: Genevieve F
authors.initials: GF
authors.lastname: Dunton
mesh_terms: D000328:Adult; D000368:Aged; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D057566:Self Report; D013997:Time Factors; D016138:Walking / Q000502:physiology*