title: Measurement of children's physical activity using a pedometer with a built-in memory.
abstract: OBJECTIVE
  We evaluated the accuracy of the Accusplit AH120 pedometer (built-in memory) for recording step counts of children during treadmill walking against (1) observer counted steps and (2) concurrently measured steps using the previously validated Yamax Digiwalker SW-700 pedometer.
  
  
  METHODS
  This was a cross-sectional validation study performed under controlled settings.
  
  
  METHODS
  Forty five 9-12-year-olds walked on treadmills at speeds of 42, 66 and 90m/min to simulate slow, moderate and fast walking wearing Accusplit and Yamax pedometers concurrently on their right hip. Observer counted steps were captured by video camera and manually counted. Absolute value of percent error was calculated for each comparison. Bland-Altman plots were constructed to show the distribution of the individual (criterion-comparison) scores around zero.
  
  
  RESULTS
  Both pedometers under-recorded observer counted steps at all three walk speeds. Absolute value of percent error was highest at the slowest walk speed (Accusplit=46.9%; Yamax=44.1%) and lowest at the fastest walk speed (Accusplit=8.6%; Yamax=8.9%). Bland-Altman plots showed high agreement between the pedometers for all three walk speeds.
  
  
  CONCLUSIONS
  Using pedometers with built-in memory capabilities eliminates the need for children to manually log step counts daily, potentially improving data accuracy and completeness. Step counts from the Accusplit (built-in memory) and Yamax (widely used) pedometers were comparable across all speeds, but their level of accuracy was dependent on walking pace. Pedometers should be used with caution in children as they significantly undercount steps, and this error is greatest at slower walk speeds.
authors.affiliation: Centre for the Built Environment and Health, School of Population Health, The University of Western Australia, Australia. georgina.trapp@uwa.edu.au
authors.forename: Georgina S A
authors.initials: GS
authors.lastname: Trapp
authors.forename: Billie
authors.initials: B
authors.lastname: Giles-Corti
authors.forename: Max
authors.initials: M
authors.lastname: Bulsara
authors.forename: Hayley E
authors.initials: HE
authors.lastname: Christian
authors.forename: Anna F
authors.initials: AF
authors.lastname: Timperio
authors.forename: Gavin R
authors.initials: GR
authors.lastname: McCormack
authors.forename: Karen
authors.initials: K
authors.lastname: Villanueva
mesh_terms: D002648:Child; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation*