Abstract: The invention relates to a movement device for mounting in a support device and a support device which entails that at least one part of the device actively moves in a continuous, predetermined fashion. The pattern of the movement occurs independently of the movement of the user. The movements entail that the muscles of the user are continuously activated changing the muscle strain of the user, which entails that the user does not get tired and sore as quickly as usually. The invention further relates to a support device, such as a bed or a chair comprising such a movement device.