For a same accelerometer, the manufacturer mentions that it can be worn at different positions on the body. However, we assume that the data are different according the accelerometer positions and the recorded activity. The aim of the study was to compare the energy expenditure values estimated by the Actigraph accelerometer according to accelerometer position on the body.

Twenty-seven elderly (71±4 years) volunteered to realize successively: 3minutes computer-based word processing, 5minutes biking (70 watts), 5minutes walking (4.6km/h) and 5minutes running (5.8km/h) on treadmill. The oxygen consumption was evaluated continuously by a gas analyzer (Metamax 3B). The energy expenditure was estimated by 3 accelerometers (Actigraph GT3X) worn on the hip, on the wrist and ankle on the dominant side (26 were right-handed and one was left-handed).

This study showed that for a same accelerometer positioned differently on the body, there are important differences in the energy expenditure estimation. This observation applies to both static and locomotor activities. Further works are necessary to find the best accelerometer position to estimate the energy expenditure in the elderly according to the activity.