Rehabilitation therapies after a serious accident or disease are usually repetitive and lengthy, requiring high motivation and adherence of the patients to achieve therapy goals. Moreover, the exercises are often painful leading to a decrease in motivation. Keeping motivation and adherence on a high level is even more challenging when the patient is a child or youth. In this paper, we address the question how to motivate this patient group to continuously attend therapy sessions and repeat the painful exercises. To address this issue, we developed the mobile application PAPP with integrated motivation concept that stimulates intrinsic and extrinsic motivation by corresponding features within the app. The intrinsic motivation is considered by means of gamification. An ice bear called “Teddy” and his journey to Spitzbergen is introduced and accompanies the patient journey. The extrinsic motivation is implemented by introducing the virtual currency “Papp-Taler” with integrated rewarding system. The usability test results show promising results. The app still requires extensions such as an external data storage to enable therapists and parents to monitor the progress. In future, it will be possible to use the app in a study to investigate whether it can motivate young patients to adhere to their therapy and whether that has a positive influence on the therapeutic outcome.