title: Validation and reliability of the New Lifestyles NL-1000 accelerometer in New Zealand preschoolers.
abstract: BACKGROUND
  Objective measures, such as accelerometers, are increasingly being used to measure physical activity (PA) levels in children, and the use of validated and reliable instruments is desirable when measuring the effectiveness of programs. The purpose of this study was to determine the validity and reliability of the New Lifestyles NL-1000 accelerometer among preschoolers using a modified version of the Children's Activity Rating Scale (CARS).
  
  
  METHODS
  Fourteen preschoolers wore the NL-1000 at their waist while the device measured activity levels [in seconds of moderate-to-vigorous physical activity (MVPA)]. They were also videoed for approximately 12 minutes while participating in normal activities at an early childhood center. At approximately 2-minute intervals, activity level readings derived from the NL-1000 were recorded. The video footage was analyzed using a modified CARS technique and the CARS scores compared with data obtained from the accelerometer.
  
  
  RESULTS
  Within subject reliability was measured using intraclass correlation coefficients (0.58 for CARS and 0.59 for NL-1000). Furthermore, 95% of the variation in CARS could be explained by variation in the accelerometer counts, with 2.4% of the variation being participant-specific.
  
  
  CONCLUSIONS
  The NL-1000 is a sufficiently reliable and valid tool for assessing MVPA in preschoolers.
authors.affiliation: Dept of Preventive and Social Medicine, University of Otago, Dunedin, New Zealand.
authors.forename: Leanne
authors.initials: L
authors.lastname: Liggett
authors.forename: Andrew
authors.initials: A
authors.lastname: Gray
authors.forename: Winsome
authors.initials: W
authors.lastname: Parnell
authors.forename: Rob
authors.initials: R
authors.lastname: McGee
authors.forename: Yvette
authors.initials: Y
authors.lastname: McKenzie
mesh_terms: D000054:Acceleration; D056044:Actigraphy / Q000295:instrumentation*; D002675:Child, Preschool; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009520:New Zealand; D015203:Reproducibility of Results; D014741:Video Recording; D055105:Waist Circumference / Q000502:physiology