title: Accuracy of piezoelectric pedometer and accelerometer step counts.
abstract: BACKGROUND
  This study aimed to assess step-count accuracy of a piezoeletric pedometer (Yamax PW/EX-510), when worn at different body parts, and a triaxial accelerometer (GT3X+), and to compare device accuracy; and identify the preferred location(s) to wear a pedometer.
  
  
  METHODS
  Sixty-three healthy adults (45.8±20.6 years old) wore 7 pedometers (neck, lateral right and left of the waist, front right and left of the waist, front pockets of the trousers) and 1 accelerometer (over the right hip), while walking 120 m at slow, self-preferred/normal and fast paces. Steps were recorded. Participants identified their preferred location(s) to wear the pedometer. Absolute percent error (APE) and Bland and Altman (BA) method were used to assess device accuracy (criterion measure: manual counts) and BA method for device comparisons.
  
  
  RESULTS
  Pedometer APE was below 3% at normal and fast paces despite wearing location, but higher at slow pace (4.5-9.1%). Pedometers were more accurate at the front waist and inside the pockets. Accelerometer APE was higher than pedometer APE (P<0.05); nevertheless, limits of agreement between devices were relatively small. Preferred wearing locations were inside the front right (N.=25) and left (N.=20) pockets of the trousers.
  
  
  CONCLUSIONS
  Yamax PW/EX-510 pedometers may be preferable than GT3X+ accelerometers to count steps, as they provide more accurate results. These pedometers should be worn at the front right or left positions of the waist or inside the front pockets of the trousers.
authors.affiliation: Lab 3R, Respiratory Research and Rehabilitation Laboratory, School of Health Sciences, University of Aveiro (ESSUA), Aveiro, Portugal.|Institute of Research in Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Cruz
authors.affiliation: Rehabilitation Science Institute and Department of Physical Therapy, University of Toronto, Toronto, ON, Canada.
authors.forename: Dina
authors.initials: D
authors.lastname: Brooks
authors.affiliation: Lab 3R, Respiratory Research and Rehabilitation Laboratory, School of Health Sciences, University of Aveiro (ESSUA), Aveiro, Portugal - amarques@ua.pt.|Institute of Research in Biomedicine (iBiMED), University of Aveiro, Aveiro, Portugal.
authors.forename: Alda
authors.initials: A
authors.lastname: Marques
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D003020:Clothing; D004867:Equipment Design; D005080:Exercise Test; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D015203:Reproducibility of Results; D016138:Walking; D055815:Young Adult