The aim of this workshop is to overview and discuss the practicalities of several new technologies for assessing physical activity and sedentary behaviour, including the most recent Actigraph GT3X+ model, the activPAL inclinometer, and the SenseWear armband. The workshop will provide information on when to use these devices (i.e., what sort of research study, who is being assessed), how to use these devices (battery charging, initialising, downloading) and data management issues.