Previous research focusing on preschoolers’healthy behaviors looked at separate behaviors, such as physical activity and sedentary behavior Currently, there is a shift in research towards focusing on an integrated approach regarding the behaviors conducted in a 24-hour day, since targeting multiple behaviors is more effective Activities in a 24-hour day consist of physical activity, sedentary behavior and sleep However, it is not yet clear how these behaviors interact and what the synergistic effects are, and there is not yet a valid measurement device to capture these 24-hour movement behaviors The aim of this project is therefore two-fold First, we will validate the Axivity accelerometer against direct observation to capture preschoolers’24-hour composition Then, the interaction between and synergistic effects of these movement behaviors will be investigated by intervening in these behaviors and evaluating the effects on preschoolers’24-hour composition Within the project, we will work closely together with both preschoolers’teachers and parents to fine-tune already existing and effective intervention strategies and mechanisms regarding these behaviors in preschoolers The effects of these changes in behaviors will be evaluated in two phases The first phase (screening phase) will look at which components have the largest positive effects The second phase (refining phase) will fine-tune the duration and intensity of the components tested in the screening phase