title: Technologies That Assess the Location of Physical Activity and Sedentary Behavior: A Systematic Review.
abstract: BACKGROUND
  The location in which physical activity and sedentary behavior are performed can provide valuable behavioral information, both in isolation and synergistically with other areas of physical activity and sedentary behavior research. Global positioning systems (GPS) have been used in physical activity research to identify outdoor location; however, while GPS can receive signals in certain indoor environments, it is not able to provide room- or subroom-level location. On average, adults spend a high proportion of their time indoors. A measure of indoor location would, therefore, provide valuable behavioral information.
  
  
  OBJECTIVE
  This systematic review sought to identify and critique technology which has been or could be used to assess the location of physical activity and sedentary behavior.
  
  
  METHODS
  To identify published research papers, four electronic databases were searched using key terms built around behavior, technology, and location. To be eligible for inclusion, papers were required to be published in English and describe a wearable or portable technology or device capable of measuring location. Searches were performed up to February 4, 2015. This was supplemented by backward and forward reference searching. In an attempt to include novel devices which may not yet have made their way into the published research, searches were also performed using three Internet search engines. Specialized software was used to download search results and thus mitigate the potential pitfalls of changing search algorithms.
  
  
  RESULTS
  A total of 188 research papers met the inclusion criteria. Global positioning systems were the most widely used location technology in the published research, followed by wearable cameras, and radio-frequency identification. Internet search engines identified 81 global positioning systems, 35 real-time locating systems, and 21 wearable cameras. Real-time locating systems determine the indoor location of a wearable tag via the known location of reference nodes. Although the type of reference node and location determination method varies between manufacturers, Wi-Fi appears to be the most popular method.
  
  
  CONCLUSIONS
  The addition of location information to existing measures of physical activity and sedentary behavior will provide important behavioral information.
authors.affiliation: National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, United Kingdom. a.loveday@lboro.ac.uk.
authors.forename: Adam
authors.identifier: http://orcid.org/0000-0002-5440-4305
authors.initials: A
authors.lastname: Loveday
authors.forename: Lauren B
authors.identifier: http://orcid.org/0000-0002-9942-5433
authors.initials: LB
authors.lastname: Sherar
authors.forename: James P
authors.identifier: http://orcid.org/0000-0003-2103-0631
authors.initials: JP
authors.lastname: Sanders
authors.forename: Paul W
authors.identifier: http://orcid.org/0000-0003-3530-4189
authors.initials: PW
authors.lastname: Sanderson
authors.forename: Dale W
authors.identifier: http://orcid.org/0000-0002-1236-6419
authors.initials: DW
authors.lastname: Esliger
mesh_terms: D000328:Adult; D004867:Equipment Design; D005260:Female; D040362:Geographic Information Systems / Q000295:instrumentation; D015438:Health Behavior; D006801:Humans; D020407:Internet; D008297:Male; D009043:Motor Activity; D057185:Sedentary Behavior; D012984:Software
keywords: context; global positioning system; real-time locating system; sitting; wearable camera