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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #165542
Title: PREDICTION OF ACTIVITY ENERGY EXPENDITURE USING ACCELEROMETERS IN CHILDREN

Author
item PUYAU, MAURICE - BAYLOR COLLEGE MED
item ADOLPH, ANNE - BAYLOR COLLEGE MED
item VOHRA, FIROZ - BAYLOR COLLEGE MED
item Zakeri, Issa
item Butte, Nancy

Submitted to: Medicine and Science in Sports and Exercise
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2004
Publication Date: 9/15/2004
Citation: Puyau, M.R., Adolph, A.L., Vohra, F.A., Zakeri, I., Butte, N.F. 2004. Prediction of activity energy expenditure using accelerometers in children. Medicine and Science in Sports and Exercise. 36(9): 1625-1631.

Interpretive Summary: Valid methods are needed to measure the physical activity levels of children. In this study we compared two accelerometer-based activity monitors in children against energy expenditure. The two monitors tested were Actiwatch (AW) and Actical (AC) activity monitors in 32 children, ages 7-18 y. Children while wearing the monitors performed structured activities including basal metabolic rate (BMR), playing Nintendo, using a computer, cleaning, aerobic exercise, ball toss, treadmill walking and running in a respiratory room calorimeter and in an exercise laboratory where their energy expenditure was measured continuously. Equations were developed to predict activity energy expenditure (AEE=EE-BMR), and physical activity ratio (PAR=EE/BMR) using counts from AW or AC, and age, sex, weight and height. Thresholds were determined to categorize sedentary, light, moderate and vigorous levels of physical activity. Overall, AW equations accounted for 76-79%, and AC equations accounted for 81% of the variability in AEE and PAR. The activity monitors classified Both activity monitors provided valid measures of children's activity levels, and can be used to discriminate sedentary, light, moderate and vigorous levels of physical activity, but require further development to accurately predict AEE and PAR for individuals.

Technical Abstract: Purpose: To validate two accelerometer-based activity monitors as measures of children's physical activity using energy expenditure as the criterion measure. Methods: Actiwatch (AW) and Actical (AC) activity monitors were validated against continuous 4-h measurements of energy expenditure (EE) in a respiratory room calorimeter and 1-h measurements in an exercise laboratory using a portable calorimeter and treadmill in 32 children, ages 7-18 y. The children performed structured activities including basal metabolic rate (BMR), playing Nintendo, using a computer, cleaning, aerobic exercise, ball toss, treadmill walking and running. Equations were developed to predict activity energy expenditure (AEE=EE-BMR), and physical activity ratio (PAR=EE/BMR) from a power function of AW or AC, and age, sex, weight and height. Thresholds were determined to categorize sedentary, light, moderate and vigorous levels of physical activity. Results: Activity counts accounted for the majority of the variability in AEE and PAR, with small contributions of age, sex, weight and height. Overall, AW equations accounted for 76-79%, and AC equations accounted for 81% of the variability in AEE and PAR. Relatively wide 95% prediction intervals suggest the accelerometers are best applied to groups rather than individuals. Sensitivities were higher for the vigorous threshold (97%) than the other thresholds (86-92%). Specificities were on the order of 66-73%. The positive predictive values for sedentary, light, moderate and vigorous categories were 80, 66, 69, and 74% for AW, respectively, and 81, 68, 72, 74% for AC, respectively. Conclusion: Both accelerometer-based activity monitors provided valid measures of children's AEE and PAR, and can be used to discriminate sedentary, light, moderate and vigorous levels of physical activity, but require further development to accurately predict AEE and PAR of individuals.