Medical services, converged with information technology, are going beyond simple health diagnosis to embrace health improvement. Applications installed in various personal devices such as mobile phones are quantifying and accumulating abundant data, ushering in the age of personalized medical service. Motivation for such IT-based unconstrained health enhancement service, however, has long been a challenge for both service providers and users. As such, the present study suggests gamification of health promotion service as one of solutions to the problem, and analyzes the principle and elements of gamification to derive effective results. In addition, it examines seven strategies from exercise studies that adopted game aesthetics and gamification, or components of the Mechanics-Dynamics-Aesthetics (MDA) framework, and applies them to user interface and avatar design.