The positive effects of physical activity on healthy populations' health are ubiquitous. Next to healthy populations, also clinical populations benefit from physical activity and a physically active lifestyle, for example to keep their disease under control or maybe even ameliorate their disease (i.e., exercise is medicine). Research previously focused on physical activity as an individual behaviour. However recently, a shift took place within research, in which physical activity is no longer seen as an individual behaviour but as a behaviour within the context of a 24-hour day. All behaviours that one can conduct within a 24-hour day can be categorised as physical activity, sedentary behaviour (sitting time) and sleep. These behaviours interact, which means that time spent on one or more of these behaviours has a consequence on the time that can be spend on the other behaviours. Only a few studies have investigated 24-hour movement behaviours within healthy populations. This concept is completely new and innovative within clinical populations. Therefore, the aim of this project is to map the 24-hour movement behaviours of clinical populations, together with the determinants of these behaviors. Information from this project will guide future intervention development regarding an optimal composition of the 24-hour day. Specifically for the starting grant, this project will be conducted with type 2 diabetes patients.