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NFL Combine: Is the 40-yard dash the best measurement of football speed?

Christopher Columbus discovered America, Paul Revere made the fateful ride, and Chris Johnson was the fastest man at the NFL combine. All facts, unless you dig deeper.

NFL: St. Louis Rams at Arizona Cardinals Matt Kartozian-USA TODAY Sports

The NFL is full of fast players. It’s always been full of fast players like Chris Johnson, Calvin Johnson, and Patrick Peterson. We know they’re fast both because they fly across the field every play and because we have at least once measured their speed. Whether it was the NFL combine or a pro day, we measure player speed in the 40-yard dash, one of the most recognizable individual drills in sports. Sure, some have questioned if the 40 is the best measurement of a player’s athletic ability, Hey, we’ve even built entirely new metrics out of that idea. It has always been a good measure of a player’s long speed, though, right?

I’ve been building and improving my Relative Athletic Scores metric for years on the idea that relative athleticism has a much better correlation to player success than a single measure of speed. Despite that, I never really questioned that the 40 was a good measurement of long speed. It makes sense on the surface, what with it being an actual measurement of speed over a long distance. In working through the data, I added in a little tweak to show how many miles per hour a player runs based on their 40. It was just a neat little way to show speed in a different way. When I calculated Chris Johnson’s speed in MPH, I noticed it was 19.3 MPH. And that got me thinking. We hear about players hitting top speeds of 20 and 21 MPH all the time, so if Chris Johnson’s 4.24, the fastest in combine history, was shy of that, how fast are these guys really? The answer, of course, is that they are not 4.24 guys. It’s that 4.24 isn’t a great measurement of top speed. So what is?

I decided to see if we can find a better measurement of top speed, and it didn’t even take all that long. It’s generally considered true that players hit their top speed before they reach the 20 yard mark, so why can’t we just use the last 20 yards? Calculating it is pretty simple. You just take a player’s 40 time, subtract their 20 yard split, and then divide that number from the final 20 yards (or 60 feet if you’re using feet per second like I do). Just like that, the miles per hour we keep hearing about totally made sense. Your 4.4 and 4.3 speed guys were hitting 20, 21 MPH in those last 20 yards and the world fell back into order. Something very interesting also shook out of that data. Some 4.6 and 4.7 players? Some of them were also hitting the same and in some cases even faster marks.

So I calculated Chris Johnson’s top speed using this method and it came in at a much more believable 22.35 MPH. 22 MPH is a lot faster than the average player and for the fastest man in combine history, it’s much more fitting. Only you’ve probably guessed that his top speed isn’t the fastest I have recorded, haven’t you? As it turns out, a whole bunch of players ran a faster back 20 than Chris Johnson did. Surely there was no rusher faster over the first 10 yards, nor the first 20. But top speed? That last 20 yards? Let’s look at just a few faster as well as a few Lions.

Miles Per Hour over Last 20 Yards of 40

Player 40 MPH
Player 40 MPH
Mario Fannin 4.41 24.06
Ben Tate 4.43 22.85
Jahvid Best 4.35 22.72
C.J. Spiller 4.37 22.72
Adrian Peterson 4.41 22.6
Latavius Murray 4.38 22.48
Chris Johnson 4.24 22.35
DeMarco Murray 4.43 22.35
Dwayne Washington 4.48 21.76
Zach Zenner 4.6 21.65
Ameer Abdullah 4.6 21.3
Theo Ridddick 4.68 20.56
40 Times and Feet Per Second Kent Lee Platte

While looking over this data, I couldn’t decide what was more interesting. Whether it was how much faster guys like Jahvid Best were compared to the rest of the universe, or just how close in top speed someone like Ameer Abdullah and Zach Zenner, both 4.6 players, were to speedsters like Dwayne Washington. It may take someone like Ameer Abdullah or a rumbler like Zach Zenner to get to top speed, while Dwayne Washington hits a similar top speed sooner and simply sustains it. There’s a lot more data for me to pore over to find some context for what this measurement can tell us. For now, I don’t even have a name for it, but just wanted to share. Some of the guys we think of as quick but slow, like Abdullah, aren’t really all that slow in terms of top speed. Others we think of as complete burners are more dependent on getting up to speed quickly than actual top speed.

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