Developmental Changes in Energy Expenditure and Physical Activity in Children: Evidence for a Decline in Physical Activity in Girls Before Puberty

ABSTRACT. Objective. To examine individual changes in energy expenditure and physical activity during prepu-bertal growth in boys and girls. Methods. Total energy expenditure (TEE), resting en-ergy expenditure, physical activity-related energy expen-diture, reported physical activity, and fat and fat-free mass were measured three times over 5 years in 11 boys (5.3 6 0.9 years at baseline) and 11 girls (5.5 6 0.9 years at baseline). Results. Four-year increases in fat (;6 kg) and fat-free mass (;10 kg) and resting energy expenditure (;200 kcal/day) were similar in boys and girls. In boys, TEE increased at each measurement year, whereas in girls, there was an initial increase from age 5.5 (1365 6 330 kcal/day) to age 6.5 (1815 6 392 kcal/day); however, b