Motion capture, or mocap, is a technique of digitally recording movements for entertainment, sports, science and medical applications. It started as an analysis tool in biomechanics research, but has grown increasingly important as a source of motion data for computer animation, as well as education, training and sports and recently for both film work and computer games. A performer wears a set of one type of marker at each joint: acoustic, inertial, LED, magnetic or reflective markers, or combinations, to identify the motion of the joints of the body. Sensors track the position or angles of the markers, optimally at least two times the rate of the desired motion. The motion capture computer program records the positions, angles, velocities, accelerations and impulses, providing an accurate digital representation of the motion.