title: Wrist-Worn Accelerometer-Brand Independent Posture Classification.
abstract: Access to raw acceleration data should facilitate comparisons between accelerometer outputs regardless of monitor brand.
  
  
  
  To evaluate the accuracy of posture classification using the Sedentary Sphere in data from two widely used wrist-worn triaxial accelerometers.
  
  
  
  Laboratory: Thirty-four adults wore a GENEActiv and an ActiGraph GT3X+ on their nondominant wrist while performing four lying, seven sitting, and five upright activities. Free-living: The same participants wore both accelerometers on their nondominant wrist and an activPAL3 on their right thigh during waking hours for 2 d.
  
  
  
  Laboratory: Using the Sedentary Sphere with 15-s epoch GENEActiv data, sedentary and upright postures were correctly identified 74% and 91% of the time, respectively. Corresponding values for the ActiGraph data were 75% and 90%. Free-living: Total sedentary time was estimated at 534 ± 144, 523 ± 143, and 528 ± 137 min by the activPAL, the Sedentary Sphere with GENEActiv data and with ActiGraph data, respectively. The mean bias, relative to the activPAL, was small with moderate limits of agreement (LoA) for both the GENEActiv (mean bias = -12.5 min, LoA = -117 to 92 min) and ActiGraph (mean bias = -8 min, LoA = -103 to 88 min). Strong intraclass correlations (ICC) were evident for the activPAL with the GENEActiv (0.93, 0.84-0.97 (95% confidence interval) and the ActiGraph (0.94, 0.86-0.97). Agreement between the GENEActiv and ActiGraph posture classifications was very high (ICC = 0.98 (0.94-0.99), mean bias = +3 min, LoA = -58 to 63 min).
  
  
  
  These data support the efficacy of the Sedentary Sphere for classification of posture from a wrist-worn accelerometer in adults. The approach is equally valid with data from both the GENEActiv and ActiGraph accelerometers.
authors.affiliation: 1Diabetes Research Centre, University of Leicester, Leicester General Hospital, Leicester, UNITED KINGDOM; 2NIHR Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit, UNITED KINGDOM; 3Alliance for Research in Exercise, Nutrition and Activity, Sansom Institute for Health Research, Division of Health Sciences, University of South Australia, Adelaide, AUSTRALIA; 4University Hospitals of Leicester, Leicester General Hospital, UNITED KINGDOM; 5NIHR Collaboration for Leadership in Applied Health Research and Care East Midlands, Leicester General Hospital, UNITED KINGDOM.
authors.forename: Alex V
authors.initials: AV
authors.lastname: Rowlands
authors.forename: Thomas
authors.initials: T
authors.lastname: Yates
authors.forename: Tim S
authors.initials: TS
authors.lastname: Olds
authors.forename: Melanie
authors.initials: M
authors.lastname: Davies
authors.forename: Kamlesh
authors.initials: K
authors.lastname: Khunti
authors.forename: Charlotte L
authors.initials: CL
authors.lastname: Edwardson
mesh_terms: D061725:Accelerometry / Q000295:instrumentation*; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture; D013848:Thigh; D014953:Wrist; D055815:Young Adult