Title: 40-yard dash
Content:  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.
Title: Stanford Routt
Content:  At the 2005 NFL Scouting Combine, Routt ran the fastest 40-yard dash at a time of 4.27 seconds, the fastest time since the NFL used electronic timing. His record was broken by running back Chris Johnson with a time of 4.24 seconds in 2008.
Title: 40-yard dash
Content:  It has been said consistently that Darrell Green recorded a time of 4.09 at the Washington Redskins' training camp in 1986. 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 time. 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. In 2013, rugby union Carlin Isles recorded a time of 4.22 at a Detroit Lions facility during a workout. In 2017, Olympic sprinter Christian Coleman ran a time of 4.12 seconds on turf in response to claims that NFL players are as fast as Usain Bolt. 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 Super Bowl in Atlanta, Georgia on February 2, 2019.
Title: Parry Nickerson
Content:  At the 2018 NFL Combine, Nickerson ran a 4.32-second 40-yard dash, which tied two other cornerbacks, LSU's Donte Jackson and Ohio State's Denzel Ward for the fastest time.
Title: 40-yard dash
Content:  The 40-yard dash is a sprint covering 40 yd. 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.
Title: Trindon Holliday
Content:  Leading up to the 2010 NFL Scouting Combine, Trindon Holliday had hoped to break Chris Johnson's record mark of 4.24 in the 40-yard dash. Holliday had self-reported running times as fast as 4.21, which seemed plausible given his extensive track background, and the fastest 100 m dash time of any football player in NCAA history. At the combine, reports of Holliday's 40-yard dash time ranged from between 4.18 seconds and 4.34 seconds. Adam Schefter, an ESPN reporter on hand at the event, had reported on Twitter that NFL scouts had clocked Holliday in as low as 4.21 during the workout. However, the NFL Network broadcast team record Holliday's two tries at unofficial times of 4.27 and 4.32, respectively, and ultimately published it as 4.34 seconds officially.
Title: Ian Johnson (American football)
Content:  Johnson ran the fastest 40-yard dash time for a running back at the 2009 NFL Combine with a 4.46. He was signed as a free agent with the Minnesota Vikings. In the fourth game of the preseason, Johnson ran for 2 touchdowns in 17 carries against the Dallas Cowboys. The following season, Johnson was waived by the Vikings on September 4, 2010. He was re-signed to the practice squad two days later.
Title: Aaron Donald
Content:  At the NFL Combine, Donald set the record for fastest 40-yard dash time for a defensive tackle with a 4.68. The record was previously held by Tank Johnson, who ran a 4.69 in 2004. He drew comparisons to John Randle afterwards. Donald was drafted by the St. Louis Rams in the first round with the 13th overall pick of the 2014 NFL Draft.
Title: Will Fuller
Content:  At the 2016 NFL Scouting Combine, Fuller ran the 40-yard dash in an official time of 4.32 seconds, which was the best time among wide receivers.
Title: Dri Archer
Content:  At the NFL Scouting Combine, Archer ran the 40-yard dash in 4.26 seconds, which is the third-fastest time ever recorded (Chris Johnson 4.24 and John Ross 4.22) since the NFL began electronic timing.

Question: who ran the fastest 40 yard dash in the nfl?
Answer: Jakeem Grant.
John Ross.