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Purpose: This study compared the accuracy of physical activity energy expenditure (PAEE) prediction using 2 methods of accounting for age dependency versus 1 standard (single) value across all ages. Methods: PAEE estimates were derived by pooling data from 5 studies. Participants, 6–18 years (n = 929), engaged in 14 activities while in a room calorimeter or wearing a portable metabolic analyzer. Linear regression was used to estimate the measurement error in PAEE (expressed as youth metabolic equivalent) associated with using age groups (6–9, 10–12, 13–15, and 16–18 y) and age-in-years [each year of chronological age (eg, 12 = 12.0–12.99 y)] versus the standard (a single value across all ages). Results: Age groups and age-in-years showed similar error, and both showed less error than the standard method for cycling, skilled, and moderate- to vigorous-intensity activities. For sedentary and light activities, the standard had similar error to the other 2 methods. Mean values for root mean square error ranged from 0.2 to 1.7 youth metabolic equivalent across all activities. Error reduction ranged from −0.2% to 21.7% for age groups and −0.23% to 18.2% for age-in-years compared with the standard. Conclusions: Accounting for age showed lower errors than a standard (single) value; using an age-dependent model in the Youth Compendium is recommended.
Pfeiffer is with the Dept. of Kinesiology, Michigan State University, East Lansing, MI. Watson and Fulton are with the Division of Nutrition, Physical Activity, and Obesity, Centers for Disease Control and Prevention, Atlanta, GA. McMurray is with the Dept. of Exercise and Sport Science and Nutrition, University of North Carolina, Chapel Hill, NC. Bassett and Crouter are with the Dept. of Kinesiology, Recreation and Sport Studies, The University of Tennessee, Knoxville, Knoxville, TN. Butte is with USDA/ARS Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX. Herrmann is with Children’s Health Research Center, Sanford Research, Sioux Falls, SD. Trost is with the Institute of Health and Biomedical Innovation at Queensland Centre for Children’s Health Research, Queensland University of Technology, Brisbane, Queensland, Australia. Ainsworth is with the School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ. Berrigan is with National Cancer Institute, Bethesda, MD.