40-yard dash

The 40-yard dash is a sprint covering 40 yards (36.58 m). It is primarily run to evaluate the speed and acceleration of American football players by scouts, particularly for the NFL Draft but also for collegiate recruiting. A player's recorded time can have a heavy impact on his prospects in college or professional football. This was traditionally only true for the "skill" positions such as running back, wide receiver, and defensive back, although now a fast 40-yard dash time is considered important for almost every position. The 40-yard dash is not an official race in track and field athletics and is not an IAAF-recognized event.

The origin of timing football players for 40 yards comes from the average distance of a punt and the time it takes to reach that distance. Punts average around 40 yards in distance from the line of scrimmage, and the hangtime (time of flight) averages approximately 4.5 seconds. Therefore, if a coach knows that a player runs 40 yards in 4.5 seconds, he will be able to leave the line of scrimmage when a punt is kicked, and reach the point where the ball comes down just as it arrives.

In terms of judging a person's speed, the best method of timing is through lasers which start and stop the times when passed through. A laser start (from a stationary position) is more accurate for measuring pure speed as it does not register a runner's reaction time. However, the method of timing a 40-yard dash can affect the accuracy by as much 0.5 seconds (with the manual stopwatch method). The National Football League (NFL) did not begin using partial electronic timing (started by hand, stopped electronically) at the NFL Scouting Combine until 1990. For purposes of measurement at the Combine, the run is made along the lower sideline from the 40 yard-line to the end zone, which has built-in rundown space.

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