We present the mechanics of the development of a visual language and analysis system enabling visual reasoning about the quality of interactions. The visual knowledge representation is designed based on aspects of human movement. Such design is justified from the fact that human possess implicit knowledge about human movement. The paper presents KIA (Kinetic Inter-Acting) encoding system that is the foundation of the visual language and respective visual analysis method. KIA enables both humans and machines to utilise information about how interactions unfold, which is necessary for practitioner–patient interaction. The paper concludes with discussion of KIA approach and technology in terms of the implications for designing for healthy living. (Source: International Journal of Medical In….