METHODOLOGY m t s

Biofeedback has been used extensively in physical medicine and rehabilitation of human joints to facilitate recovery to normal function after injury and treatments [1]. Audio and visual feedbacks are intended to encourage patients to perform rehabilitation exercises with more attention, more accurately, and more frequently by adding enter-tainment to the execution of physical exercises. The signals on the position and orientation of the body seg-ments involved in the movement exercise should provide users with valuable feedback on the quality of their performance. This can be displayed in the basic form of numbers (direct inclinations or joint angles, general scores, etc.), geometrical entities or simple bar plots [2], up to complete immersive virtual environments typical of video-games [3-7]