title: Feasibility of a Chest-worn accelerometer for physical activity measurement.
abstract: OBJECTIVE
  A "proof-of-concept" study to examine the feasibility of wearing an Actigraph GT3X+ at the Chest (resembling a neck pendant) for physical activity measurement.
  
  
  METHODS
  A convenience sample of 45 healthy adults (23 male, mean age 20.0±4.5 years) was included in data analysis.
  
  
  METHODS
  Participants simultaneously wore three GT3X+ accelerometers, on the Waist, Wrist, and Chest and completed 8 bouts of slow (.67, .89, 1.11m/s), average (1.33, 1.56, 1.78m/s) and fast (2.00, 2.22m/s) walking on a treadmill. Paired t-test, correlations and absolute percentage errors (APE) of accelerometer output (vector magnitude, VM) were computed for the key pairs: Waist-Wrist; and Waist-Chest.
  
  
  RESULTS
  The Wrist-site overestimated VM to a greater extent at all speeds in comparison to the Chest. Pearson's r correlations were weaker for Waist-Wrist (<.80) in comparison to the Waist-Chest (>.85). The APE's were much lower (i.e. higher agreement) for the Chest (9.23-15.5%) compared to the Wrist (19.7-54.9%). Participants also felt the Chest-site was more acceptable than the Waist-site.
  
  
  CONCLUSIONS
  PA measurements recorded by a Chest worn GT3X+ more closely resembled PA measurements recorded at the traditional Waist site than when compared to the Wrist site. When combined with high Chest site preference, the findings of our study suggest that the Chest is a feasible site for accelerometer wear.
authors.affiliation: Institute of Human Performance, The University of Hong Kong, Hong Kong.
authors.forename: Joni H
authors.initials: JH
authors.lastname: Zhang
authors.affiliation: Institute of Human Performance, The University of Hong Kong, Hong Kong. Electronic address: djmac@hku.hk.
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Macfarlane
authors.affiliation: Institute of Human Performance, The University of Hong Kong, Hong Kong.
authors.forename: Tanja
authors.initials: T
authors.lastname: Sobko
mesh_terms: D061725:Accelerometry / Q000295:instrumentation* / Q000379:methods; D000293:Adolescent; D000328:Adult; D015444:Exercise / Q000502:physiology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D060726:Torso; D014953:Wrist; D055815:Young Adult
keywords: Actigraph; Activity monitors; Measurement; Objective monitoring; Treadmill; Wrist worn