Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents |
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| Authors: | Kirsten Corder S?ren Brage Ambady Ramachandran Chamukuttan Snehalatha Nicholas Wareham Ulf Ekelund |
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| Institution: | 1. MRC Epidemiology Unit , Cambridge, UK kirsten.corder@mrc-epid.cam.ac.uk;3. MRC Epidemiology Unit , Cambridge, UK;4. Diabetes Research Centre and M. V. Hospital for Diabetes , Chennai, India |
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| Abstract: | Abstract 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. |
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| Keywords: | Accelerometry movement sensor activity monitor physical activity intensity |
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