7. A method according to claim 1 wherein said processing determines the acceleration of at least one point.
1. A computer based exercise method comprising the steps of: providing an exercise machine on which a person exercises, wherein said exercise machine resists the effort of said person when exercising; providing a computer and a computer-controlled video display for viewing by said person; electro-optically determining data concerning a plurality of points on at least one of said person and said machine; processing said data to determine a variable related to one or more of said points; and using said determined variable, controlling a video game program in said computer.