Energy Cost Expression for a Youth Compendium of Physical Activities: Rationale for Using Age Groups

Pediatr Exerc Sci. 2018 Feb 1;30(1):142-149. doi: 10.1123/pes.2016-0249. Epub 2017 Nov 11.


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.

Keywords: MET; adolescents; children; energy expenditure.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Energy Metabolism*
  • Exercise / physiology*
  • Female
  • Humans
  • Male
  • Metabolic Equivalent*
  • Reference Values