Jadeveon Clowney ran the 40-yard dash in 4.53 seconds, which only confirmed that the South Carolina star is an incredible athlete. But how freakishly insane is that time? The 40-yard dash, like every other aspect of the combine, is only useful when placed in proper context. The dash is biased in favor of lighter players; one way to control for this drawback is to measure Clowney only against defensive ends and linebackers, although that doesn’t totally solve the weight issue. That’s one reason Football Outsiders has published a Speed Score for running back prospects, calculated as (Weight * 200)/(40 time^4).

The website NFLsavant.com is an excellent source of historical combine data going back to 1999. I looked at all the defensive ends and outside linebackers with 40-yard times over that period, and ran a few regressions to get a sense of the relationship between weight and speed. A simple one worked just as well as the more complicated ones, and that formula produced an R^2 of 0.30. That best-fit formula was 40-yard time = 3.609 + 0.00455*weight. So for Clowney, at a weight of 266 pounds, he would be projected to run the 40 in 4.82 seconds. Since Clowney actually ran it in 4.53 seconds, that means he was 0.29 seconds faster than we would expect.

That is really, really good, although you already knew that. Here’s some more context. NFLSavant.com has 706 defensive ends or outside linebackers since 1999 with 40-yard times. Clowney, by rating 0.29 seconds better than expected, comes in ahead of 700 of those players. The other five?

Lawrence Sidbury, from Richmond, came in with identical numbers (266, 4.53) to Clowney in 2009. But the small school prospect was three inches shorter, and only a 4th round pick of the Falcons that year. He stayed in Atlanta for four years before moving on to the Colts last season.

In 2011, two players produced even better times than Clowney, after adjusting for weight. Texas A&M’s Von Miller (246, 4.42, +.31) had a great combine and then was selected with the second overall pick in the draft; on the other hand, Nevada’s Dontay Moch (248, 4.40, +.34) was an undersized player drafted by Cincinnati in the third round; his career has been marked my injuries and a suspension, not production.

The final two players come from the class of 2002, and both turned in long careers. Dwight Freeney (266, 4.48, +.34) was another undersized prospect from Syracuse who turned into a Hall of Fame caliber pass rusher in Indianapolis. The other name might be surprising, as the man with the single best adjusted 40 time among pass rushers is a player who rarely exhibited great athleticism in the NFL. It’s former Jet and UAB product Bryan Thomas (266, 4.47, +.35, and at the same 6’5 as Clowney), who had an 11-year tenure with New York but totaled just 33.5 sacks. Thomas’ combine production was lauded at the time, of course — he had a faster time in the 40 than 25 of the 29 running backs that year — but that level of freak athleticism disappeared when the pads came on.

The table below shows all first round picks who came to the combine as either a defensive end or outside linebacker from 1999 to 2013. For each player, I’ve listed his draft year, his weight and 40 time according to NFL Savant, his draft pick, his projected 40 based solely on his weight, and the difference between his actual time and projected time. Note that several of the 40 times are from Pro Days, and not the combine. Ideally, we’d be only comparing combine times for every player, but this is the world we live in.

For my money, Mario Williams remains the most freakish pass rushing prospectof this era. After adjusting for weight, his 40 time was nearly as good as Clowney’s, but what sets Williams apart is the other combine tests. The most notable of those was a 40.5″ vertical jump, which is among the most insanely athletic marks in combine history considering he weighed 295 pounds. Clowney, even at 29 pounds lighter, hit only 37.5″ on his vertical jump, and Williams also blew Clowney away in the bench press despite being two inches taller.