title: Commercially available pedometers: considerations for accurate step counting.
abstract: BACKGROUND
  Many commercially available pedometers undercount, especially at slower speeds. We examined the effects of age, obesity, and self-selected walking speed on pedometer accuracy. We also compared the accuracy of piezoelectric and spring-levered pedometers at slow walking speeds.
  
  
  METHODS
  Study 1: 259 subjects walked on a motorized treadmill at two self-selected walking speeds. Steps were counted using a spring-levered pedometer. Study 2: 32 subjects walked on a motorized treadmill at slow walking (1.0-2.6 MPH) speeds. Steps were counted using spring-levered and piezoelectric pedometers.
  
  
  RESULTS
  Study 1: self-selected walking speed and pedometer accuracy decreased with increasing age, weight, and body mass index (BMI). Accuracy was 71% below 2.0 MPH, 74-91% between 2.0 and 3.0 MPH, and 96% above 3.0 MPH. Decreased accuracy was best predicted by increasing age. Study 2: between 1.8 and 2.0 MPH, the accuracy of the piezoelectric pedometer (>97%) exceeded that of the spring-levered pedometers (52-95%). Even at 1.0 MPH, accuracy of the piezoelectric pedometer (56.4 +/- 33.8%) was superior to the spring-levered pedometers (7-20%).
  
  
  CONCLUSIONS
  Accuracy of all pedometers tested exceeded 96% at speeds 3.0 MPH, but decreased at slower walking speeds. In individuals that naturally ambulate at slower walking speeds (e.g., elderly), we recommend the use of more sensitive (e.g., piezoelectric) pedometers.
authors.affiliation: Center for Human Nutrition, University of Colorado Health Sciences Center, Denver, CO 80262, USA. Ed.melanson@uchsc.edu
authors.forename: Edward L
authors.initials: EL
authors.lastname: Melanson
authors.forename: Joan R
authors.initials: JR
authors.lastname: Knoll
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Bell
authors.forename: William T
authors.initials: WT
authors.lastname: Donahoo
authors.forename: J O
authors.initials: JO
authors.lastname: Hill
authors.forename: Lana J
authors.initials: LJ
authors.lastname: Nysse
authors.forename: Lorraine
authors.initials: L
authors.lastname: Lanningham-Foster
authors.forename: John C
authors.initials: JC
authors.lastname: Peters
authors.forename: James A
authors.initials: JA
authors.lastname: Levine
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D003120:Colorado; D005080:Exercise Test / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D009765:Obesity; D015203:Reproducibility of Results; D019876:Sports Equipment / Q000592:standards*; D016138:Walking