title: Comparison of Kenz Lifecorder EX and ActiGraph accelerometers in 10-yr-old children.
abstract: A new accelerometer, the Kenz Lifecorder EX (LC; Suzuken Co. Ltd, Nagoya, Japan), offers promise as a feasible monitor alternative to the commonly used Actigraph (AG: Actigraph LLC, Fort Walton Beach, FL).
  
  
  OBJECTIVE
  This study compared the LC and AG accelerometers and the Yamax SW-200 pedometer (DW) under free-living conditions with regard to children's steps taken and time in light-intensity physical activity (PA) and moderate to vigorous PA (MVPA).
  
  
  METHODS
  Participants (N=31, age=10.2 +/- 0.4 yr) wore LC, AG, and DW monitors from arrival at school (7:45 a.m.) until they went to bed. Time in light and MVPA intensities were calculated using two separate intensity classifications for the LC (LC_4 and LC_5) and four classifications for the AG (AG_Treuth, AG_Puyau, AG_Trost, and AG_Freedson). Both accelerometers provided steps as outputs. DW steps were self-recorded. Repeated-measures ANOVA was used to assess overlapping monitor outputs.
  
  
  RESULTS
  There was no difference between DW and LC steps (Delta=200 steps), but a nonsignificant trend was observed in the pairwise comparison between DW and AG steps (Delta=1001 steps, P=0.058). AG detected significantly greater steps than the LC (Delta=801 steps, P=0.001). Estimates of light-intensity activity minutes ranged from a low of 75.6 +/- 18.4 min (LC_4) to a high of 309 +/- 69.2 min (AG_Treuth). Estimates of MVPA minutes ranged from a low of 25.9 +/- 9.4 min (LC_5) to a high of 112.2 +/- 34.5 min (AG_Freedson). No significant differences in MVPA were seen between LC_5 and AG_Treuth (Delta=4.9 min) or AG_Puyau (Delta=1.7 min).
  
  
  CONCLUSIONS
  The LC detected a comparable number of steps as the DW but significantly fewer steps than the AG in children. Current results indicate that the LC_5 and either AG_Treuth or AG_Puyau intensity derivations provide similar mean estimates of time in MVPA during-free living activity in 10-yr-old children.
authors.affiliation: Walking Research Laboratory, Department of Exercise and Wellness, Arizona State University, Mesa, AZ 85212-0180, USA. james.mcclain@asu.edu
authors.forename: James J
authors.initials: JJ
authors.lastname: McClain
authors.forename: Susan B
authors.initials: SB
authors.lastname: Sisson
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Washington
authors.forename: Cora L
authors.initials: CL
authors.lastname: Craig
authors.forename: Catrine
authors.initials: C
authors.lastname: Tudor-Locke
mesh_terms: D002648:Child; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D009864:Ontario; D005082:Physical Exertion; D016138:Walking