[JumperPride1]

Explain laser timed. What does it consist of?

The clock is started and stopped by the body breaking the plane of a beam of light at the beginning and end of a 40 yard sprint. A few ways of doing this, including wearing sensors on the shoe, and also with the use of video monitors (like those you see at the state track meet). It takes the user error out of the 40 timing, but does have its limitations.