“…The introduction of videodisk technology using players with still frame, step frame, and slow play features greatly improved this process, 4 and collections of video clips of more complicated systems such as polevaulters, high jumpers, 5 and colliding automobiles 6 became available. The advent of frame-grabbers and digitizing 7,8 led to the development of point-and-click analysis tools such as VideoPoint™, 9 and VideoGraph™. 10 These tools have simplified the analysis of other complicated situations such as amusement park rides, bodies of leaping ballet dancers and spring-board divers, 11 and the pursuit-and-evasion problem.…”