User representations in interactive systems are essential for the development of effective, efficient and satisfactory tools. In mixed reality, this representation is called an avatar and describes virtual characters through which users interact. Visual-motor synchronization of avatar and user creates the feeling of embodying the avatar and accepting it as your own body. This makes avatars a promising tool for many applications, such as anxiety therapy, treatment of body image disorders or firefighter training, as people can be confronted with challenges in a simulation without putting them in danger. Previous work shows that avatars can change users’ behavior, attitudes and perceptions. For example, users show higher cognitive performance when they embody an avatar that looks like Albert Einstein and perceive the world through the eyes of a child when they adopt a low perspective. While previous work focused on the effects of audiovisual representation of avatars, haptics has only recently become more important. Current work shows, for example, that lifting weights is perceived as easier when muscular avatars are embodied. Although haptics could increase immersion and open up new possibilities for applications such as psychotherapy or learning manual and movement skills, fundamentals of visual-haptic avatar design and its impact on self-perception remain largely unexplored. In this project, the effect of the visual representation of avatars in combination with haptic stimuli on users’ self-perception is systematically examined. Users not only perceive the world from another body, but also feel it accordingly. This increases immersion, helps empathize with avatars, enables new mixed reality applications and expands our understanding of the underlying phenomena. In empirical studies we investigate the effects of haptically-visually presented avatars on self-perception. We determine how the avatar’s visual appearance affects perceived strength, endurance and body shape. For example, a muscular avatar could cause weights to be perceived as lighter. Additionally, we integrate haptic feedback devices (such as exoskeletons and weight-changing devices) that dynamically influence physical performance, e.g. B. by manipulating effort when lifting weights. We combine both research directions to investigate the interaction between avatar appearance and haptic feedback, show systematic effects and convert them into a model.