Tennessee Titans running back Chris Johnson is no doubt fast. He ran a 4.24 at the 2008 NFL Scouting Combine for the best time that year (supposedly the best ever is Deion Sanders’ 4.17, but timing systems have changed dramatically over the years). Johnson’s speed was on display often this year as he became the sixth back to top 2,000 yards rushing in a season, set an NFL record for yards from scrimmage and he had three touchdown runs of 85 yards or longer – no other player has managed that in a career.

Still, Johnson would seem a little delusional when he boasts that he believes he can beat the fastest man alive, Jamaican sprinter Usain Bolt, in a race. The question is: Will we ever see that race?

Thanks to Bodog, you can bet on that possibility. It offers these three prop bets:

Will Chris Johnson and Usain Bolt race before Aug. 1, 2010:
Yes +220
No –280

--Who will win the race between Johnson and Bolt:
Johnson +500
Bolt –1000

--If Johnson and Bolt race the distance will be:
Over 60 meters 3/2
Under 60 meters 9/5
Exactly 60 meters 5/4

Well, according to an ESPN report, don’t waste your money on those last two options in the race distance. Johnson said Monday the he was told that a potential race against Bolt won’t happen at a distance less than 100 meters. Of course, Bolt holds the world record and Olympic gold in that event as well as the 200 meters.

“He don't want to do it. He only wants to run the 100, he don't want to run the 50," Johnson said. "He said the only way he'll do it is if he runs the 100."

But the good news from that report is that members of Johnson’s and Bolt’s camp are at least talking about a potential race for charity. However, then Bolt’s agent pretty much threw cold water on the chance, even denying ESPN’s report.

“(Bolt) has a schedule and a coach to follow and there is no chance that we would set up this type of event," said agent Ricky Simms.

Nick Saban said he would never be the coach of Alabama, too.

If my math is correct, Johnson’s 40-yard dash time would equate to nearly 11 seconds in the 100 meters. And one study showed that Bolt’s 40-yard split at the Beijing Games was 4.35.

But this is all so unscientific.

For example, a 100-meter runner does not accelerate out of the block as quickly as someone running a 40 because the sprinter has to sustain his speed longer. So he probably reaches top speed after 40 yards. For example, in the 200 meters at the Olympics, Bolt covered the distance between 60 meters and 80 meters in 1.61 seconds. In addition, the fastest 100 meters Bolt has ever run actually was the final 100 of his 200 meters at the world championships last year, which he covered in 9.27 seconds

And don’t forget about reaction time for sprinters in dealing with a starter’s pistol and the fully automatic timing system in track. Most 40-yard dashes start with the runner beginning on his own and breaking the electronic eye. So, once you subtract Bolt’s standard reaction time from his projected 4.35 40 at Beijing – the average time it takes an elite sprinter from the gun to the moment they exert pressure on the starting block’s electronic pads is about .15 seconds -- his time drops to 4.20.

But that’s not to say some of these running backs couldn’t at least hang with Bolt. Florida running back Jeffrey Demps, when he was still technically a high schooler, ran a 10.01 at the 2008 Olympic Trials. LSU’s Trindon Holliday has been clocked at 4.27 in the 40 and he has a personal best in the 100 meters of 10.00, which he ran to win the national title in the 2009 NCAA Outdoor meet.

Let’s face it, this is probably a whole lot of nothing. The race probably won’t happen because Bolt, who doesn’t even follow football or live in this country, has nothing to gain while Johnson can make a worldwide name for himself. It would be interesting however, to see the NFL stage some sort of competition like this at the Pro Bowl, say Devin Hester vs. Chris Johnson. Now that I would bet on.