Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents.
This aim of this study was to compare the new Actigraph (GT1M) with the widely used Model 7164. Seven days of free-living physical activity were measured simultaneously using both the Model 7164 and GT1M in 30 Indian adolescents (mean age 15.8 years, s = 0.6). The GT1M was on average 9% lower per epoch than model 7164, thus a correction factor of 0.91 is suggested for comparison between the two monitors. The differences between monitors increased in magnitude with intensity of activity (P < 0.001) but remained randomly distributed (r = 0.01, P = 0.96). No significant difference was observed between monitors for time spent in moderate (P = 0.31) and vigorous (P = 0.34) physical activity when using the same epoch length. The Model 7164 classified less time as sedentary (P < 0.001) and more time as light-intensity activity (P < 0.001) than the GT1M. In conclusion, data from the GT1M can be compared with historical data using average counts per minute with a correction factor, and the two models might be comparable for assessing time spent in moderate to vigorous physical activity in children when using the same epoch length.
Corder
Kirsten
K
MRC Epidemiology Unit, Institute of Metabolic Science, Box 285 Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. kirsten.corder@mrc-epid.cam.ac.uk
Brage
Søren
S
Ramachandran
Ambady
A
Snehalatha
Chamukuttan
C
Wareham
Nicholas
N
Ekelund
Ulf
U
D000054:Acceleration; D000293:Adolescent; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D008954:Models, Biological; D008962:Models, Theoretical; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D008991:Monitoring, Physiologic; D009043:Motor Activity / Q000502:physiology*; D009068:Movement / Q000502:physiology*