re: What would Usain Bolt's 40 yard dash time be?

Here are the splits when Bolt ran a 9.58





RT: 0.14

0-10: 1.89
10-20: 0.99
20-30: 0.90 (3.78 @ 30m)
30-40: 0.86 (4.64 @ 40m)
40-50: 0.83

40 yards == 36.576 meters.

Bolt was at 3.78 at 30 meters and he ran the next 10 meters in 0.86. As you can see, he is still accelerating at that point, so multiplying 0.86 * 0.576 would be a slight underestimate of his 40 time. But as you can see, his rate of acceleration has drastically slowed down at that point. There is a way to figure out the exact time he took to travel that .576 meters, but I don't know how to do it, and I do know that since his next split was .83, simply dropping the 0.86 down to a .85 makes for a very close approximation. So that's what we're gonna do.

3.78 + (0.85 * 0.576) == 4.27 seconds.

BUT BUT BUT, in the olympics the clock starts the gun, and at the combine the clock starts when the runner starts.

This is where the reaction time comes into play.

4.27 - 0.14 == 4.13 seconds. Damn...that's fast.

(1) BUT BUT BUT, sprinters get a starting block, which helps lessen the effect of the reaction time because they can come off the block more quickly.

AND

(2) BUT BUT BUT, sprinters are running on a track, not on turf.

AND

(3) BUT BUT BUT, you looked at the data for Bolt's Best. Race. Ever. He doesn't run that fast every time.

So start with the time of 4.13 and adjust upwards based on the three BUT BUT BUT factors. The third factor is discretionary. You can always just run the numbers from whatever race you wish. All of them will be slower than the above numbers since it was by far his best race ever.

To deal with BUT BUT BUT factors #1 and #2....well I don't know what you do. How much time is the track worth versus the turf? How much time are starting blocks worth? I don't know the answers to those questions. Perhaps somebody else does.

Either way, in view of all of the above, if Bolt shows up at the combine with only 3 opportunities to post a time in the 40 yd dash, I would bet against him posting a sub 4.2 time. Could he conceivably do it? Sure...see above. But, again, that is all best case scenario and doesn't account for some potentially slowing factors.

My Ultimate Conclusion #1:
I think Chris Jonson vs. Usain Bolt in a 40 yd dash would be a tight race.

My Ultimate Conclusion #2:
A sub 4.10 40 yd dash has been run twice in history. Once by the Easter Bunny. The other time by Santa Claus.