Feasibility of the Tritrac R3D Accelerometer to Estimate Energy Expenditure in Youth

in Pediatric Exercise Science
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The purpose of this study was to determine whether an equation could be developed to predict energy expenditure from Tritrac output, body mass, stature, and age in youth. The participants were 308 young people, 8–18 yrs of age, similarly dispersed across ages and genders. Stature (cm) and body mass (kg) were measured. Participants completed 10 min of nine activities, ranging from light to vigorous intensity. Simultaneous measures of Tritrac vector magnitude counts (VMAG) and oxygen uptake (Cosmed K4b2) were obtained. Mixed model analysis using VMAG, sex, age, stature, and body mass fit well, and all variables were significant (p ≤ .012). The model concordance correlation was Rc = .812; standard deviation = 305ml/min. A slightly less complex model was also adequate: VO2 (ml/min) = (0.32·VMAG) + (6.97·cm) + (6.19·kg) − 858; standard deviation = 306 ml/min; Rc =.809. These results indicate that the Tritrac R3D can be used with some success to assess energy expenditure in 8- to 18-year olds.

The authors are with the University of North Carolina, Chapel Hill, NC 27599. McMurray is with the Dept. of Exercise & Sport Science, Baggett is with the Dept. of Epidemiology, Harrell is with the School of Nursing, and Pennell and Bangdiwala are with the Dept. of Biostatistics.