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 race.
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 can run 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, this method of timing a 40-yard dash can affect the accuracy by as much as 0.5 seconds with the manual stopwatch method.
The National Football League (NFL) did not begin using partial electronic timing (i.e. started by hand, stopped electronically) at the NFL Scouting Combine until 1999. 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, and for electronically timed 40-yard dashes, the runner is allowed to start when they wish, and a timer hand-starts the clock.
In contrast, track and field races have the runner react to a starting gun, which takes approximately 0.24 second (based on FAT timing); further to this, IAAF rules state any runner with a reaction time of less than 0.1 second is subject to disqualification.
This aspect means that comparisons with track times are essentially impossible given that a reaction time is not factored in, and the use of hand-timing in the 40-yard dash can considerably alter a runner's time: the methods are not comparable to the rigorous electronic timing used in track and field.
Bo Jackson claimed to have run a 40-yard dash with a time of 4.13 s, and there were also reports of Jackson running a 4.12 at the 1986 combine. Texas Tech's Jakeem Grant was hand-timed by a New Orleans Saints scout as running a 4.10 in 2016, potentially beating Jackson's record. In the early 1980s, Baylor's Gerald McNeil ran a 4.19-second 40-yard dash before being signed to the United States Football League (USFL).Deion Sanders ran a 4.27-second 40-yard dash in 1989.
A year and a half after he retired from active competition, Usain Bolt ran a 4.22 in running shoes and a tracksuit at a promotional event for the Superbowl in Atlanta, Georgia on February 2, 2019.
This is a list of the official 40-yard dash results of under 4.31 seconds recorded at the NFL Scouting combine since 1999, the first year electronic timing was implemented at the NFL Scouting Combine.
|4.22||John Ross||5 ft 11 in (1.80 m)||190 lb (86.2 kg; 13.6 st)||Wide receiver||Washington||2017||No. 9 overall by Cincinnati Bengals|||
|4.24||Rondel Menendez||5 ft 9 in (1.75 m)||192 lb (87.1 kg; 13.7 st)||Wide receiver||Eastern Kentucky||1999||No. 247 overall by Atlanta Falcons|
|Chris Johnson||5 ft 11 in (1.80 m)||192 lb (87.1 kg; 13.7 st)||Running back||East Carolina||2008||No. 24 overall by Tennessee Titans|
|4.26||Jerome Mathis||5 ft 11 in (1.80 m)||184 lb (83.5 kg; 13.1 st)||Wide receiver||Hampton||2005||No. 114 overall by Houston Texans|
|Dri Archer||5 ft 8 in (1.73 m)||173 lb (78.5 kg; 12.4 st)||Running back||Kent State||2014||No. 97 overall by Pittsburgh Steelers|
|4.27||Henry Ruggs III||6 ft 0 in (1.83 m)||190 lb (86.2 kg; 13.6 st)||Wide receiver||Alabama||2020||No. 12 overall by Las Vegas Raiders|
|Stanford Routt||6 ft 2 in (1.88 m)||193 lb (87.5 kg; 13.8 st)||Cornerback||Houston||2005||No. 38 overall by Oakland Raiders|
|Marquise Goodwin||5 ft 10 in (1.78 m)||181 lb (82.1 kg; 12.9 st)||Wide receiver||Texas||2013||No. 78 overall by Buffalo Bills|
|4.28||Champ Bailey||6 ft 0 in (1.83 m)||192 lb (87.1 kg; 13.7 st)||Cornerback||Georgia||1999||No. 7 overall by Washington Redskins|
|Jacoby Ford||5 ft 9 in (1.75 m)||190 lb (86.2 kg; 13.6 st)||Wide receiver||Clemson||2010||No. 108 overall by Oakland Raiders|
|Jalen Myrick||5 ft 10 in (1.78 m)||200 lb (90.7 kg; 14.3 st)||Cornerback||Minnesota||2017||No. 222 overall by Jacksonville Jaguars|||
|J. J. Nelson||5 ft 10 in (1.78 m)||156 lb (70.8 kg; 11.1 st)||Wide receiver||UAB||2015||No. 159 overall by Arizona Cardinals|||
|DeMarcus Van Dyke||6 ft 1 in (1.85 m)||187 lb (84.8 kg; 13.4 st)||Cornerback||Miami||2011||No. 81 overall by Oakland Raiders|
|4.29||Fabian Washington||5 ft 11 in (1.80 m)||188 lb (85.3 kg; 13.4 st)||Cornerback||Nebraska||2005||No. 23 overall by Oakland Raiders|
|Zedrick Woods||5 ft 11 in (1.80 m)||205 lb (93.0 kg; 14.6 st)||Safety||Mississippi||2019||Undrafted|||
|Javelin Guidry||5 ft 9 in (1.75 m)||191 lb (86.6 kg; 13.6 st)||Cornerback||Utah||2020||TBD|
|4.30||Darrent Williams||5 ft 9 in (1.75 m)||176 lb (79.8 kg; 12.6 st)||Cornerback||Oklahoma State||2005||No. 56 overall by Denver Broncos|
|Tye Hill||5 ft 10 in (1.78 m)||185 lb (83.9 kg; 13.2 st)||Cornerback||Clemson||2006||No. 15 overall by St. Louis Rams|
|Yamon Figurs||5 ft 11 in (1.80 m)||174 lb (78.9 kg; 12.4 st)||Wide receiver||Kansas State||2007||No. 74 overall by Baltimore Ravens|
|Darrius Heyward-Bey||6 ft 2 in (1.88 m)||210 lb (95.3 kg; 15.0 st)||Wide receiver||Maryland||2009||No. 7 overall by Oakland Raiders|||
|Jamel Dean||6 ft 1 in (1.85 m)||206 lb (93.4 kg; 14.7 st)||Cornerback||Auburn||2019||No. 94 overall by Tampa Bay Buccaneers|||
According to a five-year NFL combine report, wide receivers and cornerbacks had the fastest average times at 4.48, followed by running backs at 4.49. The following average times were measured between 2000 and 2012 at the NFL combine for players who played at least 5 games.
Intent on building a fast team, [Paul Brown in the mid-1940s] began timing players in the 40-yard dash, rather than the 100, reasoning that the 40 was a more meaningful measure of true football speed: about the distance a player would cover on a punt.