Active Voice: A New Youth Compendium of Physical Activities

By Kathleen B. Watson, Ph.D., David Berrigan, Ph.D., and Janet E. Fulton, Ph.D., FACSM

Kathleen B. Watson, Ph.D. David Berrigan, Ph.D. Janet E. Fulton, Ph.D., FACSM
Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily represent positions or policies of ACSM or the Centers for Disease Control and Prevention (CDC).

Kathleen B. Watson, Ph.D., is an epidemiologist in the Physical Activity and Health Branch of the CDC in Atlanta, Georgia. Her research interests include surveillance and measurement of physical activity, physical activity and its association with health and community-level strategies for promoting physical activity. Dr. Watson co-leads activities across federal agencies to update and maintain national goals and objectives for physical activity. In addition, she has published more than 100 scientific articles.

David Berrigan, Ph.D., is a biologist in the Division of Cancer Control and Population Sciences at the US National Cancer Institute (NCI) in Bethesda, Maryland. Dr. Berrigan has studied metabolism and energetics of physical activity and sedentary behavior in diverse ectotherms, mice and humans. Currently, Dr. Berrigan’s work focuses on the environmental and contextual determinants of health behaviors. He is strongly committed to public health via prevention.

Janet E. Fulton, Ph.D., FACSM, is an epidemiologist and the chief of the Physical Activity and Health Branch of the CDC in Atlanta, Georgia. In addition to publishing more than 100 scientific articles, Dr. Fulton has contributed to many federal documents, including the
2008 Physical Activity Guidelines for Americans, Physical Activity Guidelines for Americans Midcourse Report: Strategies to Increase Physical Activity among Youth, and Step It Up! The Surgeon General’s Call to Action to Promote Walking and Walkable Communities.

This commentary presents Dr. Watson’s, Dr. Berrigan’s and Dr. Fulton’s perspectives on the above-captioned topic. Along with a large group of experts in youth energy expenditure, these three SMB co-authors led a joint CDC/NCI/NCCOR (NCCOR: National Collaborative for Childhood Obesity Research) workgroup for the Development of a Youth Compendium of Physical Activities. This resulting paper was published under a similar title and appears in the February 2017 issue of Medicine & Science in Sports & Exercise® (MSSE).

An important resource for physical activity researchers and practitioners is information about the amount of energy required to engage in various physical activities. Energy expenditure values provide a vital tool for connecting physical activity behavior and health.

The Adult Compendium of Physical Activities is a widely accepted tool to estimate and classify energy expenditure for a multitude of activities in which adults participate. The Adult Compendium uses METs (metabolic equivalent of tasks) as a standardized measure of energy expenditure, with the assumption that one MET is the energy expenditure of a person at rest. MET is calculated as activity metabolic rate divided by the resting metabolic rate. Recognizing the usefulness of physical activity energy expenditure values for children and youths, Ridley and colleagues developed the first compendium of energy expenditure for young people. Although this was an important first step, there were several limitations: 1) nearly two-thirds of the data was obtained from adults; 2) MET values were derived from studies with small sample sizes; and 3) MET values did not vary across ages (5 to17 years), although energy expenditure for the same activity is known to vary by age in children.

An Updated Youth Compendium of Physical Activities

We presented an updated “Youth Compendium of Physical Activities” in the February 2018 issue of MSSE. This work resulted from a partnership between the CDC, the NCI, the NCCOR and an international group of leading researchers.

At a meeting in April 2012, an international group of experts agreed that an updated, expanded and web-accessible youth compendium would be a valuable contribution to the field. The Working Group on Youth Energy Expenditure then began work on three main tasks.

First, the working group concluded the best metric that would function across four age groups, sex and physical characteristics was the youth METs (METy). This is conceptually like adult METs. However, adult MET uses 3.5 ml.kg-1.min-1 for the energy cost for resting adults, whereas METy uses Schofield sex- and age-specific basal metabolic rate equations. Details of this work have been described in other papers, e.g., PLOSOne, 2015.

Second, the expert group updated the previous literature review to include new estimates of youth energy expenditure for additional physical activities. During this process, gaps were identified in some activities and for some ages. To fill these gaps, the group identified new data through a solicitation for papers published in the Journal of Physical Activity and Health.

Third, and finally, the group used data from two systematic reviews, plus pooled data among individuals from four studies and papers in the Journal of Physical Activity and Health supplement to develop the Youth Compendium of Physical Activities. This work involved steps to:
  • Perform multiple imputation of missing METy values;
  • Smooth observed and imputed METy values;
  • Develop a coding scheme for this Youth Compendium;
  • Classify physical activities into 16 major categories.
The new Youth Compendium presents the energy costs of 196 physical activities derived exclusively from pediatric data, expressed in terms of METy, for four age categories. Although this compendium advances the work of Ridley and other independent investigators, some important gaps remain. These include a lack of measured energy expenditure for occupational activities in young people, as well as limited data for children younger than six years and for young people with disabilities.

We anticipate this new Youth Compendium will be a valuable resource for researchers and practitioners interested in improving the health of children and adolescents through physical activity. For additional information, go to: http://www.nccor.org/nccor-tools/youthcompendium/.