In our current society it is important to promote physical activity among young children. Therefore, it is necessary to accurately measure the free-living physical activity. The equations used in older children and adolescents (age 6 till 18 years) cannot be used in the younger children, due to a difference in resting metabolic rate.

In most cases an accelerometer is used to measure energy expenditure in real life. Through various studies and validations, this is certainly possible in older children. But for younger children, this has yet to be validated. To validate the accelerometer in this study, the Actigraph, an indirect room calorimeter is used.

In the study five children were included to wear the Actigraph while inside the room calorimeter. To determine the baseline, the kids were instructed to watch TV for half an hour. Subsequently, various activities were carried out in different intensities, from sedentary to vigorous.

A room calorimeter is often used for studies in older children and adults, but is considered impractical for younger children. The current study found out that it is doable for young children to complete a short structured protocol in a room calorimeter. It would be an improvement to make the room child friendly and more open for a pleasant stay. It can be concluded that a room calorimeter is a practical method and a reasonable possibility for metabolic research and validation studies in young children.