A method of measuring a user's range of motion, comprising: tracking user movement of at least one body portion using at least one sensor； correlating the tracked user movement to an avatar of the user in a virtual environment using at least one controller； displaying on an output device the summation of tracked user movement graphically in the virtual environment such that user movement with respect to the user is represented in the virtual environment as avatar movement with respect to the avatar, in the same relative relationship.
