OK, I too have seen the splits for Bolt’s record 100m sprint.
Are there any mathemeticians out there who can figure out what his 40 yard time would be, if his 30 m (32.8 yards) split was 3.78 and his 40m (43.745 yards) was 4.65 ?
I’m not strong in math 
I ask simply because I love to have the ammunition in my arsenal when I hear all of my college football players talk 40 times - this will help me with the folly of hand timed 40’s, and give me something tangible to compare with.
Thanks!
Check back in a little while - I gotta cruise the rest of the forums first.
I also need his 20m split and 50m split, and reaction time.
Don’t waste your breath (seriously). First of all you can’t compare times because track&field timing is actually accurate/consistent and 40y is not. Second of all, Bolts 40 time is going to come out to like 4.30 which will invalidate your potential argument anyway.
Just say “Ben ran 3.7. Bolt kicked Ben’s ass. Bolt 3.6”. That might work. Another thing to ponder…I think Thompson might have kicked Bolt’s ass to 40y in this 9.69 race.
Mort
I think I mis-represented myself. I want to know what Bolt’s 40 time is - say it is a 4.3 - so that when my players say “Big school player X” ran a 4.13 I can say that there’s no way he’s that fast, because the fastest man in the world ran a 4.3…or something to that effect.
Oh well
Ah I see. Let’s see what the other members come up with. This topic p***** me off as I’m sure it does you too. I roll with this http://www.signonsandiego.com/uniontrib/20050418/news_1s18forty.html
From PJ’s splits, there is no definitive 40 yard time; it can be one of two things.
At the 40 yard mark:
4.35 or 4.36 for the clock.
4.19 for how long he’d been running.
Then when we try the arduous process of converting that to a “football 40”, we get something like the following…
Subtract .25 to 0.40 for the timer reacting to the movement. Now we’re at 3.94 to 3.79.
Add or subtract 0.10 for timers misjudging the finish, and we get 4.04 to 3.69.
Ben got to 40m in 4.66 in Seoul, and ran a 3.7 football 40.
Bolt got to 40m in 4.65 in Beijing.
To be honest, probably the easiest indicator of a “football 40” time is the runner’s time at the 30m mark. It seems pretty close. Ben was 3.80 in Seoul, and Bolt was 3.78 in Beijing.
Here’s my math taken from the splits that PJ posted:
RT 0.165
10m 1.85
20m 2.87 (1.02)
30m 3.78 (0.91)
40m 4.65 (0.87)
50m 5.50 (0.85)
60m 6.32 (0.82)
70m 7.14 (0.82)
80m 7.96 (0.82)
90m 8.79 (0.83)
100m 9.69 (0.90)
40yd=36.5760 meters
Take the .87 split from the 30-40m mark and divide it by 10 in order to get meter to meter time and you get .087 (which is obviously not constant due to acceleration; however there is only 4 hundredths margin for error between the .91 20-30m and .87 30-40m)
Multiply .087 x 6.5760 (the amount of meters above 30 equivalent to the 40yd mark) and you get .572112
Add .572112 to 3.78(30m split) and you arrive at 4.35(FAT) for the 40yd
For an idea of the hand time you have 3 possible scenarios:
1- subtract .24 from 4.35 to account for human error on stopwatch and the RT and you arrive at 4.11 (starting the timer on first movement).
2- take the 4.35 and subtract RT of .165 and get 4.185 for a manually started laser finish.
3- take the 4.185 and subtract .2 for a 3.985
Option 3 might be a hell of a lot more likely than you’d think because I manually start and laser time my guys and the coaches who are standing by with their watches routinely clock them at .2 faster than the time on my laser (even though all of us are starting our timers on first movement).
Again, the 4.35 does not account for acceleration; however the margin for error is only .04
Consider the following:
audio reaction time (avg): .15
visual reaction time (visual): .20
-40y dash athlete starts (add +.15 to account for FAT reaction time)
-coach sees athlete start (add +.20 to account for visual reaction time)
IMO, if everyone is very alert 40y hand + .35=40y FAT.
On an aside, I hear Stephfon Green (red shit frosh. RB at PSU) runs 4.25. He’s runs 6.52 55m and ~11.00 but is faster than Bolt. Anyone care to guess how 4.25 40y = 6.52 (60.15y)?
1.You will almost never see a guy who runs 4.3hand on Turf or better, who didn’t also realize their potential as a sprinter as well.
1.A Almost never, because I can’t think of anyone off the top of my head that did not compete at track and some point during their career: either hs or college.
1.B That means almost all the skilled position players in the NFL some sort of sprinting backgrounds. Therefore almost all them would be classified as sprinters.
2. If I said that Asafa Powell had better hands than Jerry Rice, everyone would be in an uproar.
2.A So why don’t you see NFL players in the finals if their so fast. Anyone can run unatt. Because at some point during their career, they figured that a 10.2 or 10.8 is not as good as making millions of dollars.
3. NFL players cannot beat elite sprinters for 40yds. Neither can sprinters out play NFL players on a football field. Put Usaine Bolt in pads and it would be hiliarious. Put Deion Sanders on the track and he runs 10.27 and loses to college sprinters.
4. A few lucky players have been able to do both.
5. I made five points but I only have four to make.
Good stuff.
Interestingly I subtract .20 from my manually started/laser finish times in order to give the coaches/scouts the figure in ‘hand time’ language.
It’s funny, I must convert fact to science fiction in order to speak the common language.
In the history of American football all the way up to current Indianapolis tryouts the common language is science fiction; meanwhile, the T&F community has long since dealt with fact.
Add at least .2 -.24 to all those times at Indianapolis and pro days in order to get the ‘real’ time (void of reaction time).
I used to think these combines were such a big deal then I attended one. The thing is, they have a coach, maybe a couple of assistants timing these guys. Half the time they are not paying attention. The head coach is basically telling these guys to hurry up so we can get to the real drills, scrimmages, games etc. I watched about 50 football players struggle to break 5.0 on grass. I thought wow and these guys are supposed to be faster than sprinters.
Unless you have been to one of these combines, you wouln’t understand. I love when they have the shuttle starts. Go…go…go. What a joke!
The football time is from first motion etc. It’s just a different kettle of fish. Ben ran a 3.7 football style 40y but his E time out of blocks would be much slower since he was 3.80e for 30m (Bolt was 3.78 and Thompson was a bit under that)
Your assumption that he runs the entire 30m-40m at the same speed changes the result by up to 0.01, and I think the assumption is faulty. Almost every time, an elite sprinter is accelerating through that segment.
Well, rainy here, it must really being raining hard enough where you are located for your view of the computer screen to be obscured because if you read my post again you’ll see how I twice mention the fact that my simple math does not account for acceleration and that the margin for error was no greater than .04 relative to the 20-30m split and 30-40m split.
Hmm, you’re right, sorry.
Your actual error was only 0.01, so not bad!
40yd = 36.576m
10m / 0.87 = 11.494m/s
6.576 / 11.494 = 0.572 for 6.576m (at 11.494m/s)
0.572 (6.576m) + 3.78 (30m) = 4.35
Same result as James Smith, but a quicker route to calculate it 
How are you determining the .01 error margin?
delete please
I start by assuming PJs splits are rock-solid (which isn’t true). Your 0.04 was presumably from an 0.01 error at each interval? I compare speeds of 20m-30m, 30m-36.576, 36.576m-40m, 40m-50m.
If we use .57 for the 6.576m, then Bolt goes
10.99m/s for 20m-30m
11.53m/s for 30m-40y
11.41m/s for 40y-40m
11.76m/s for 40m-50m
This is possible, but those speeds have an issue.
If we use .58 for the first 6.576m, then Bolt goes
10.99m/s for 20m-30m
11.33m/s for 30m-40y
11.81m/s for 40y-40m
11.76m/s for 40m-50m
These speeds also have the problem.
It’s much better if we use .575 for the first 6.576m; this gets us
10.99m/s for 20m-30m
11.43m/s for 30m-40y
11.61m/s for 40y-40m
11.76m/s for 40m-50m
Nothing outside .57, .575, and .58 is reasonably possible due to speed irregularities.
Adding this to the previous times, we get 4.355.
Since only those three mini-splits to 40y are possible, the possible times at 40y are only 4.35, 4.355, and 4.36. 4.355 gets rounded to 4.36 anyway, so you’re out by up to 0.01.
After a few days you have to subtract another 0.2 for the people who “have a friend who knows someone who was there and saw the whole thing.”