The Caloric Cost of Submaximal Walking and Running in Children and Adolescents

Abstract

0074 Previous research has provided models for estimating the caloric cost of exercise in adolescents, but not for pre-adolescent children. PURPOSE: The purpose of this study was to develop and cross-validate generalized models for estimating relative steady-state caloric expenditure (kcal/kg/min) in children and adolescents during submaximal walking and running. METHODS: Subjects were 101 boys and 79 girls, ages 9–18 years. Each subject performed a submaximal treadmill exercise test at randomly selected walking and running speeds from 2–8 mph. Caloric expenditure was estimated from steady-state oxygen uptake and respiratory exchange ratio through open-circuit spirometry. The sample was randomly divided into a derivation sample and cross-validation sample, each with 90 subjects. RESULTS: Multiple regression revealed that the relationship between caloric expenditure and running speed was linear (p<.05), but for walking speed was curvilinear (p<.05). The restricted model is: Caloric cost (kcal/kg/min) = 0.004 + (0.033xSpeed) − (0.058xWalk = 1, Run = 0) + (0.002xSpee d2 × Walk = 1, Run = 0), R = .93, SEE = 0.021 kcal/kg/min. Age accounted for additional variation in caloric expenditure (p<.05). The full model is: Caloric cost (kcal/kg/min) = 0.038 + (0.033xSpeed) – (0.054xWalk = 1, Run = 0) + (0.002xSpeed2 × Walk = 1, Run = 0), – (0.003xAge), R = .94, SEE = 0.020 kcal/kg/min. Cross validation revealed very little shrinkage in either the restricted model (R = .91, Error = 0.025 kcal/kg/min) or the full model (R = .92, Error = 0.023 kcal/kg/min). CONCLUSION: These data demonstrate that the relative caloric cost of exercise can be accurately estimated from submaximal steady-state walking and running speed in youth. Estimation of caloric expenditure during exercise in children and adolescents may provide a means for balancing caloric input with output and preventing undue weight gain.