Assessment of energy expenditure in children using the RT3 accelerometer

Stavros Kavouras, Stavros Sarras, Yiannis Tsekouras, Labros Sidossis

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The aim of this study was to evaluate the utility of the RT3 accelerometer in young children, compare its accuracy with heart rate monitoring, and develop an equation to predict energy expenditure from RT3 output. Forty-two volunteers (mean age 12.2 years, s = 1.1) exercised at two horizontal and graded walking speeds (4 and 6 km · h-1, 0% grade and 6% grade), and one horizontal running speed (8 km · h-1, 0% grade), on a treadmill. Energy expenditure and oxygen consumption ([Vdot]O2) served as the criterion measures. Comparison of RT3 estimates (counts and energy expenditure) demonstrated significant differences at 4, 6, and 8 km · h-1 on level ground (P < 0.01), while no significant differences were noted between horizontal and graded walking at 4 and 6 km · h-1. Correlation and regression analyses indicated no advantage of vector magnitude over the vertical plane (X) alone. A strong relationship between RT3 estimates and indirect calorimetry across all speeds was obtained (r = 0.633-0.850, P < 0.01). A child-specific prediction equation (adjusted R2 = 0.753) was derived and cross-validated that offered a valid energy expenditure estimate for walking/running activities. Despite recognized limitations, the RT3 may be a useful tool for the assessment of children's physical activity during walking and running.

Original languageEnglish (US)
Pages (from-to)959-966
Number of pages8
JournalJournal of Sports Sciences
Issue number9
StatePublished - Jul 2008
Externally publishedYes


  • Energy expenditure
  • Exercise
  • Heart rate
  • Oxygen consumption

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation


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