Table 2 Movement Visualisation (MV) Groups

Indirect MV

Body movements are not directly visualized in the virtual environment. Changes in context information represent indirectly the user’s movement

Subgroups

 Optical flow (N = 11): Motion of patterns or objects create a naturalistic illusion of movement in the virtual environment. Goal is usually navigation through a virtual scenario (e.g. supermarket)

 Active optical flow (N = 3): Motion of patterns or objects during movement in the virtual environment is manipulated with the purpose to influence the user’s behavior (e.g. acceleration of optical flow)

Abstract MV

The user’s movement is represented in a (non-anthropomorphic) computer graphic. Main goal relies on the correct execution of the task

Subgroups

 2D Exercise (N = 6): tasks performance in a two dimensional environment

 3D Exercise (N = 5): task performance in a three dimensional environment

Augmented reality (AR) MV

Visualisation of the user’s real body supplemented with virtual Performance Feedback and/or virtual Context Information (e.g. Sony Eye Toy, AR-glasses). This also includes Augmented Virtuality

Avatar MV

Real movements are represented through a virtual body (or body part)

Subgroups

 Realistic body (or body part) (N = 3): Representation visually and kinematically close to the real body

 Rough figure (N = 2): Simple body representation with some aspects of real appearance and movements (e.g. Mii avatar in Nintendo Wii)

 Mirrored body (or body part) (N = 0): Realistic body representation with mirrored visual and movement information

Tracking MV

Continuous adjustment of body movement with an external visual input (e.g. follow a given trajectory). Explicit goal is the correctness of the movement execution

Combined MV

Visualisation consists of more than one MV type (e.g. indirect MV on an augmented reality device)

No MV

Body movements are not represented in the virtual environment. Visualisation during rehabilitation training is exclusively based on Performance Feedback