People struggle to recover from injuries due to the lack of commitment to their rehabilitation exercises as they are often boring. Recent approaches that involve the use of interactive video games have shown positive results in exercising as users engage in physical activity while playing a game. For example Nintendo Wii and Microsoft Kinect based games have shown to be effective in the treatment of post stroke patients. Yet, there are not tools in the market that offer portable rehabilitation exercises in the form of interactive games. The work presented in this paper focuses on the development of the Mobile RehApp™, an augmented reality based application for mobile devices designed for therapeutic support that aims to assist physiotherapists and patients on ankle sprain rehabilitation.