title: Comparison of four ActiGraph accelerometers during walking and running.
abstract: Currently, researchers can use the ActiGraph 7164 or one of three different versions of the ActiGraph GT1M to objectively measure physical activity.
  
  
  OBJECTIVE
  To determine whether differences exist between activity counts from the ActiGraph 7164 and the three versions of the GT1M at given walking and running speeds.
  
  
  METHODS
  Ten male participants (23.6 +/- 2.7 yr) completed treadmill walking and running at 10 different speeds (3-min stages) while wearing the ActiGraph 7164 and the latest GT1M (GT1M-V3) or the GT1M version one (GT1M-V1) and the GT1M version two (GT1M-V2). Participants walked at 3, 5, and 7 km x h(-1) followed by running at 8, 10, 12, 14, 16, 18, and 20 km x h(-1). The accelerometers were worn on an elastic belt around the waist over the left and right sides of the hip. Testing was performed on different days using a counterbalanced within-subjects design to account for potential differences attributable to accelerometer placement. At each speed, a one-way repeated-measures ANOVA was used to examine differences between activity counts in counts per minute (cpm). Post hoc pairwise comparisons with Bonferroni adjustments were used where appropriate.
  
  
  RESULTS
  There were no significant differences between activity counts at any given walking or running speed (P < 0.05). At all running speeds, activity counts from the ActiGraph 7164 and GT1M-V2 displayed the lowest and highest values, respectively. Output from all accelerometers peaked at 14 km x h(-1) (mean range = 8974 +/- 677 to 9412 +/- 982 cpm) and then gradually declined at higher speeds. The mean difference score at peak output between the ActiGraph 7164 and GT1M-V2 was 439 +/- 565 cpm.
  
  
  CONCLUSIONS
  There were no statistically significant differences between outputs from all the accelerometers, indicating that researchers can select any of the four ActiGraph accelerometers in doing research.
authors.affiliation: University of Tennessee, Department of Exercise, Sport, and Leisure Studies, Knoxville, TN 37996-2700, USA. djohn1@utk.edu
authors.forename: Dinesh
authors.initials: D
authors.lastname: John
authors.forename: Brian
authors.initials: B
authors.lastname: Tyo
authors.forename: David R
authors.initials: DR
authors.lastname: Bassett
mesh_terms: D000054:Acceleration; D000328:Adult; D004867:Equipment Design; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012420:Running; D013714:Tennessee; D016138:Walking; D055815:Young Adult