There are many drills held to assess prospects at the NFL Combine, but none of them have the mystique or cultural cache of the 40 yard dash. Strength, agility and intelligence are all crucial ingredients to NFL success, but speed is both quantifiable and easily visible in a way that separates it from other criteria. The top 40 yard times reveal a mix of Hall of Fame players or future Hall of Fame entrants and one-season wonders or prospects who fizzled out, so the 40 yard dash is clearly not a reliable indicator of future success. It will nevertheless remain a topic of discussion, a highlight for fans and a source of excitement.

In 2000, the NFL began officially timing the 40 yard dash with electronic equipment to ensure exact measurements, a welcome advancement for players, talent evaluators and fans alike. This list, however, will include hand-recorded times measuring back before the change to electronics, as well as times recorded at college pro days, rather than solely those from the NFL Combine. The times recorded in earlier eras include room for human error, which some may feel tarnish the purity of the list, but I feel that it is important to include them. Removing any times before the 2000 change ignores a rich collection of NFL history, and implies that sports history that cannot be scientifically verified is irrelevant. While unreliable legends of 3.9 second 40 yard dashes should be given little respect, the older times on this list were recorded by NFL officials or scouts and were the basis for teams' decisions on draft days. Questions should be asked about the exact veracity of the older numbers, and a measure of doubt when reviewing them is not only understandable, but helpful. The times nonetheless stand as testaments to the athletic ability of the players who ran to record those times, and deserve to be known and remembered by football fans.

19 T19. James Jett (1993), Stanford Routt (2005), Devin Hester (2006), Darren McFadden (2008), Trindon Holliday (2010), Jacoby Ford (2010), Marquise Goodwin (2013), 4.27 seconds

Former Oakland Raiders owner Al Davis coveted the fastest players in every draft, and drafted four of the seven players mentioned above (Jett, Routt, McFadden and Ford). Jett, a wide receiver who played his entire nine year career with the Raiders, had even won an Olympic gold medal at Barcelona as a member of the US 4x100m relay team, one year before being drafted.

Of the other players in this group, the noticeable standout is Hester, who holds the NFL record for most career special teams return touchdowns with 19, as well as several other season and single-game returns records.

18 18. Dri Archer (2014), 4.26 seconds

The most recent entry on this list was recorded by Archer, a running back from Kent State who was selected in the third round of the 2014 NFL Draft, 97th overall. His time is the second fastest electronically recorded official 40 yard dash time since its introduction in 2000. Archer also excelled as a kick returner in college, and will likely feature prominently in the Steelers special teams.

17 T15. Jerome Mathis (2005), 4.25 seconds

Mathis' official Combine time is 4.26 seconds, but his personal best was recorded earlier that year. The Hampton wide receiver and kick returner was selected in the fourth round of the 2005 Draft by the Houston Texans, and he made the Pro Bowl team as a rookie, serving as the team's kick returner. Foot injuries and a February 2008 arrest, however, led to his release by the Texans later that year. He was briefly signed by the Redskins in 2008 but did not play, and has since only had short stays in the CFL and the Arena League.

16 T15. Michael Vick (2001), 4.25 seconds

Like Mathis, Vick's best time came away from the Combine, where he recorded a 4.33 time. As the only quarterback on this list, it will come to little surprise to many that he has also more career NFL rushing yards than any quarterback in history. Whether you love him for his athletic ability or hate him for his dogfighting past, there's no denying Vick's speed has made him one of the most electrifying athletes to ever play the quarterback position.

15 T15. Randy Moss (1998), 4.25 seconds

Ever the character, Moss's time came from Marshall's pro day after he elected to not attend the NFL Combine. The surefire future Hall of Famer used his speed to achieve the second-most career receiving touchdowns with 156 and to gain the single season receiving touchdowns record (23, in 2007 with New England) and rookie receiving touchdowns record (17, 1998 with Minnesota).

14 T12. Taylor Mays (2010), 4.24 seconds

The hard-hitting USC safety was timed at 4.43 seconds at the combine, an impressive feat for a DB. The three-time All-American was drafted in the second round by the San Francisco 49ers, but the team then traded him to the Bengals in 2011 for a seventh round draft pick. He remains with the team, but has started only four games in his three seasons in Cincinnati.

13 T12. Chris Johnson (2008), 4.24 seconds

Johnson's 4.24 time remains the NFL Combine record since the introduction of electronic timing. Drafted out of East Carolina University by the Tennessee Titans in the first round in 2008 (24th overall), he then became only the seventh player to reach 2,000 rushing yards in one season in 2009. He also broke Marshall Faulk's single season records for yards from scrimmage with 2,509. While he has gained over 1,000 yards in each of his four seasons since, his inconsistency led the Titans to release him in April 2014. He signed a two year contract with the Jets later that month.

12 T12. Rondel Melendez (1999), 4.24 seconds

Unfortunately for the Eastern Kentucky wide receiver, Melendez's 40 yard dash time remains the highlight of his career. He was drafted in the seventh round, 247th overall, by the Atlanta Falcons, but never played in the NFL.

There are no photos of Melendez in this world, so we opted to use a photo of the team that drafted him.

11 11. Willie Parker (2004), 4.23 seconds

The former Pittsburgh Steelers running back demonstrated great speed in college at North Carolina, but his perceived lack of vision resulted in him going undrafted. Picked up by the Steelers as a free agent, he provided a stark alternative to well-loved power back Jerome Bettis, and eventually became the starter in his own right. In his six year career, Parker made two Pro Bowls, won two Super Bowls and set the record for the longest Super Bowl run at 75 yards during Super Bowl XL against Seattle.

10 10. Donte Stallworth (2002), 4.22 seconds

Stallworth's blazing speed led the Saints to select him 13th overall in 2002, and he remained a consistent player from 2002-2007, despite never putting up a 1,000 yard season. In 2009, Stallworth pled guilty to DUI manslaughter charges, and he served 30 days in jail as well as many hours of community service, as well as a suspension for the entire 2009 season. He has played for six different teams, and is currently a free agent.

9 T7. Don Beebe (1989), 4.21 seconds

Beebe, a receiver and returner drafted in the third round by the Bills in 1989, shares the NFL record with six career Super Bowl appearances. Beebe was a member of all four Bills Super Bowl teams, none of which won the game, and a member of the Packers in Super Bowls XXXI and XXXII, the former of which he won. He also used his famous speed to catch up to Dallas Cowboys defensive tackle Leon Lett in Super Bowl XVII and cause him to fumble before he could run his fumble recovery back for a touchdown.

8 T7. Kevin Curtis (2003), 4.21 seconds

The speedy slot receiver was selected in the third round by the St. Louis Rams, where he partnered with Isaac Bruce and Torry Holt to form one of the most formidable receiver groups in the NFL at the time. After enjoying success in St. Louis, he signed with the Philadelphia Eagles, catching for over 1,000 yards in 2007. In 2008, however, he suffered the first in a series of injuries and never returned to form, ending his career in 2011.

7 T7. Deion Sanders, 4.21 seconds

The NFL Hall of Famer not only used his speed to cover wide receivers and electrify crowds in the return game, but to play baseball as well. He is the only player to play in both a Super Bowl (he won Super Bowl XXIX with San Francisco and Super Bowl XXX with Dallas) and in a World Series (1992 with the Braves, who lost to the Blue Jays in six games). As an eight-time Pro Bowler, two-time NFL Defensive Player of the Year and NFL 1990s All-Decade team member, his football career will understandably serve as his primary legacy. He now works as an analyst on the NFL Network.

6 6. Joey Galloway, 4.18 seconds

The speedy Ohio State receiver was drafted eight overall in 1995 by the Seattle Seahawks, and he recorded his first of six 1,000 yard seasons as a rookie. Galloway finished with nearly 11,000 receiving yards over his sixteen year career, which he spent in Seattle, Dallas, Tampa Bay, New England, Pittsburgh and Washington.

5 5. Ahman Green (1998), 4.17 seconds

The four-time Pro Bowl running back was a third round selection of the Seattle Seahawks, but he is most famous for his time with Green Bay. He won two national championships with Nebraska, and had six seasons of over 1,000 yards in the NFL. His best season came in 2003, where he recorded 1,883 yards, 15 touchdowns and a career-best 98 yard touchdown run. He still stands as Green Bay's all time leading rusher, and is one of just two running backs with multiple touchdown runs of 90 or more yards in their career.

4 4. Darrell Green (1983), 4.15 seconds

The Hall of Fame cornerback made seven Pro Bowls, won two Super Bowls with the Redskins (XXII and XXVI) and was named to the NFL 1990s All-Decade Team, yet his greatest accomplishment is likely his longevity. Green played a total of twenty seasons, all with the Redskins, and did not retire until after the 2002 season at the age of 42. He is the oldest cornerback to ever play in the NFL and holds the record for most consecutive seasons with an interception at 19. In 2010, on his 50th birthday, he even tweeted that he timed himself as running a 4.43 second 40 yard dash. His nickname “The Ageless Wonder” is therefore fully deserved.

3 3. Alexander Wright (1990), 4.14 seconds

Selected in the second round by the Dallas Cowboys, who aspired to partner him with their first round pick, running back Emmitt Smith, Alexander's speed never manifested into sustained success. Wright won the NFL's Fastest Man Competition in 1992 and 1993 and still holds a Cowboys record with a 102 yard return touchdown in 1991, but never caught more than 462 yards in one season. After three seasons with Dallas, three seasons with the LA Raiders and two seasons with the St. Louis Rams, he retired in 1996.

2 2. Michael Bennett (2001), 4.13 seconds

Bennett's official time at his pro day was 4.28 seconds, but his earlier time of 4.13 seconds in collegeputs him second best all time. Selected 27th overall by the Vikings, he reached the Pro Bowl in 2002 after running for 1,296 yards and receiving for an additional 351 yards. The following year, however, he suffered injuries that largely derailed his career. After being released by the Vikings after the 2005 season, he spent time with the Saints, Chiefs, Buccaneers, Chargers and Raiders, finishing his career in September 2011.

1 1. Bo Jackson (1986), 4.12 seconds

After winning the Heisman Trophy at Auburn and putting up the best 40 yard dash time ever, he was drafted first overall by the Tampa Bay Buccaneers, but Jackson refused to sign with them as they desired for him to sacrifice his baseball career. He was re-selected in the seventh round by the LA Raiders in 1987, and served as an electrifying running back for the team from 1987-1990. His 221 rushing yards on November 30, 1987 still stands as a Monday Night Football record. A serious hip injury in the 1990 NFL playoffs led him to decide to retire from football to focus on baseball, but he remains the only athlete to be named as an All-Star in multiple major American sports.