The study examines the association of digitally provided EMPOWER - exercise intervention on 3-6-year-old child's physical activity (PA), motor performance and quality of life (QoL) during and after cancer treatment. In addition, the factors that influence the feasibility of the intervention will be examined. The research is carried out in cooperation with Turku University of Applied Sciences, Turku and Tampere University Hospitals. Cancer treatments significantly reduce the amount of PA of the child impairing the normal motor development. Delay in normal motor development may cause childhood cancer survivors a higher risk of developing adverse health effects in adulthood. Data on children's PA and condition is collected using questionnaires and sensors. In addition, children's motor performance and QoL are examined through tests and questionnaires. The feasibility of the intervention will be examined from the parents and nursing staff through questionnaires and interviews.