title: A comparative analysis of pedometry in measuring physical activity of children.
abstract: OBJECTIVE
  The purpose of this study was to examine the step and physical activity time output features of the Walk4Life LS2505 pedometer under field physical activity conditions.
  
  
  METHODS
  Data were collected on 288 (12.62 +/- 1.23 yr) participants during a school-based structured physical activity program. Participants' physical activity levels were concurrently measured via the Yamax SW701 (Yamax Corp., Japan) and Walk4Life LS2505 (Walk4Life Inc., Plainfield, IL) pedometers, and System for Observing Fitness Instruction Time (SOFIT) physical activity coding mechanism. Relative and absolute agreement between SW701 (criterion) and LS2505 steps per minute, and SOFIT (criterion) and LS2505 physical activity time (min) were analyzed overall, and across physical activity content themes and physical activity quartiles.
  
  
  RESULTS
  Physical activity measure correlations were moderately strong to strong (r = 0.85-0.98, P < 0.05); however, the LS2505 significantly underestimated steps per minute (M(diff) = 6.37 +/- 5.79, P < 0.05) and overestimated physical activity time (M(diff) = -7.73 +/- 3.13, P < 0.05). When LS2505 steps per minute were examined across physical activity themes and quartiles, clinically acceptable absolute error scores (<or= 10 +/- 5%) were found when physical activity was mostly continuous, or intermittent and moderate to high. The LS2505 physical activity time measure was clinically acceptable only when physical activity was continuous.
  
  
  CONCLUSIONS
  It is recommended that the LS2505 pedometer output of time only be employed when physical activity is continuous, or when physical activity is continuous, or intermittent and moderate to high for the output of steps.
authors.affiliation: Department of Kinesiology, University of Wisconsin, Madison, WI 53706, USA. pwscruggs@education.wisc.edu
authors.forename: Philip W
authors.initials: PW
authors.lastname: Scruggs
mesh_terms: D000293:Adolescent; D002648:Child; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D015146:Midwestern United States; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009043:Motor Activity; D019370:Observation; D010806:Physical Education and Training; D012574:Schools