Term gamification involves applying elements and principles of computer games to motivate and engage people in a context that is not a computer game. Implementation of gamification should not be trivial, and it's important to understand and apply game elements in a given context which is succesful for the users. In the theoretical part of the work, user experience is studied, then the process of user experience is described in detail. Then, the visual design guidelines for Android platform are described. Finally, the term gamification and it's usage and influence in user experience design is defined. Research and practical work of thesis includes: competitive mobile application analysis, target audience analysis and personas creating. Furthermore, the functionality of the authors mobile application is described, leading to the creation of a prototype. The prototype of the author's mobile application is tested and questioned through a survey. The main purpose of this thesis is to study how implementation of gamification in applications can have a positive effect to motivate users to improve their physical activity.