![]() ![]() The first step in the imputation process was to fit linear and quadratic regression models to determine the structure of the relationship between each age group and MET y cost for each activity that had a sufficient number of observations (Proc GLM, SAS). For the imputations, each specific mean value for each age group for each activity was treated as one observation. Missing MET y values for specific age groups and activities were imputed. Tables with all the values were then developed. Age group-specific mean MET y values were calculated for each specific activity. Activities were classified into 16 major categories taking into consideration body position (sitting, standing, lying down), upper or lower body movement, locomotion, weight or non-weight bearing, and intensity of effort. ![]() The EE data included 196 activities, including walking, running, and cycling at specific speeds. In total, EE of physical activities used for the new Youth Compendium were extracted from 137 pediatric studies representing more than 37,000 observations on children and adolescents up to age 18 years, the pooled dataset, and the JPAH supplement (Butte 2017). The use of BMR provides more consistency for calculating the MET value within each age group. The group realized that METs are usually calculated from resting metabolic rates and not basal metabolic rates (BMR), but if the two are measured in a post absorptive state, the difference is negligible (Schultz and Jequier. ![]() This decision was based on poor consistency of measured basal EE values from the pooled data set and missing values from other published studies. The MET y was calculated from basal metabolic rate equations as published by Schofield (1985). The workgroup also decided to use a youth MET (MET y) metric to present the EE information. Including values for children younger than age 6 years was not possible due to the paucity of activity and metabolic data. This decision was the clearest and most feasible approach to account for the age dependence of basal metabolic rate, as well as other age-specific changes in MET score that are likely related to biomechanical efficiency and other factors. Additional information on the early development of the Youth Compendium can be found in the Background and History section of this website.īased on preliminary analyses of the pooled data set, an a priori decision was made to divide the values presented in the Youth Compendium into four age groups-6 to 9, 10 to 12, 13 to 15, and 16 to 18 years. NCCOR’s Youth Energy Expenditure (YEE) workgroup used three data sets-a pooled data set from five research groups, data from an extensive literature review, and data from a special supplement on youth physical activities-and an imputation process to develop the new Youth Compendium of Physical Activity. ![]()
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