I'll dispense with the question/answer format of the previous installations. When talking about recruits, especially skill position players, defensive backs, and linebackers, people get enamored with a kid's reported time in the 40 yard dash. People get excited about a wide receiver who can run the 40 in 4.4 seconds or shorter. People go "ho-hum" when a kid runs it in 4.5 seconds or longer.
I can see why this is so. It's an easy way for people who are amateurs at evaluating talent to measure the level of athletic ability of a player. I am certainly one of those amateurs, and I have been guilty of going all googly-eyed over a sub-4.4. Now, however, I think the measurement is utterly meaningless in evaluating a recruit. Let's look at some reasons why:
1. They're self-reported
Who tells Rivals or Scout what a recruit ran in the 40? Usually, either the recruit or his coach. Do these people have any incentive whatsoever to be truthful about a mediocre run? Absolutely not. At best, you can expect that if a recruit runs 10 times and gets 4.6, 4.6, 4.7, 4.6, 4.5, 4.45, 4.6, 4.5, 4.7, and 4. 5, you can expect that the player will report that he ran a 4.4. Message boards across the land will then cheer him.
2. 40-times are dependent upon running conditions
This is something that the NFL has figured out. A player's 40 time is highly dependent on weather and track conditions at the time it is run. A guy on a high-tech polymer track will run much faster than a guy on a dirt track. A guy will run much faster with the wind at his back than with it still or at his front. A guy will run a little faster in warm weather than in cold.
This means that 40 times are not absolute measures of speed, but are only good when compared relative to people who ran under the exact same conditions. So, did that running back in Tennessee run his 40 yard dash under the same conditions as that cornerback in Michigan? Doubt it.
3. They're greatly inflated (deflated) in recent years
Jerry Rice's reported 40 time in his draft year was 4.6 seconds. Jerry Rice is the greatest wide receiver in history. He holds almost every receiving record the NFL records. He was plenty fast. He couldn't be covered. If you believe his 40 time, he was slow.
I think what has happened is that high school coaches and players have started "teaching to the test". They know that people love to see a 4.4 40-time, so they will work to give it to them. You can engineer 40 time by working on technique and the strengths of particular muscles. Does changing your track technique help make you a better football player? I sincerely doubt it. Does working on particular muscles help make you a better football player? Maybe, but they aren't working on those muscles to help with football. They're working on those muscles to help with track. Any benefit to football is incidental.
4. They're measured without pads
This is a common complaint about it, often made by knuckleheads who just want to defend a particular recruit who reported a poor 40 time. Unfortunately, it's also a correct criticism. All 40 times are measured without football pads. Some people, for reasons I do not understand, lose more speed with pads on than others will lose.
5. Straight-line speed over 40 yards is not particularly important in football
Don't get me wrongly here. I'm not saying slow people are just as good as fast people in football. Clearly not. However, rarely will a guy be called upon to run 40 yards in a straight line in football. It'll happen occasionally, but not that often. Much more often, a player will be required to make quick cuts, power through a block/tackle, run in a straight line for a shorter distance, etc. Straight line speed over half the football just isn't all that important. Maybe we should be measuring times in the 10 yard dash instead. That will be important for a running back trying to outrun linebackers, a cornerback closing on a receiver, a quarterback escaping a rush, a defensive lineman trying to run down a scrambling QB, and many other things. 40 yards? Eh, not so much.
We're talking about explosion. The ability to go from 0-to-100 in an instant. Fortunately, there is another measurement of explosionthat is frequently reported, and we'll get into that in a bit.
6. Players bodies change a lot once they get to college.
Almost every recruit has to make significant changes to his body upon getting to college. Some have to lose a little fat. Almost all have to add strength. This means adding muscle. This means adding weight. This means changing the way you run. Think about it like this. Let's say you take a car that runs really fast. Then you put a more powerful engine in it, but also add weight. Will it be faster or slower? I don't know, and neither will you until you make the change and test it.
So, in short, the problems with the 40 times are thus. People lie about them. Even if people didn't lie about them, they would only be accurate measures if measured under identical conditions. They're engineered by coaches and players who are more interested in improving the score rather than improving in football. They measure straight-line speed under non-game conditions. Straight line speed over that distance is not especially important. And last but not least, every recruit's 40 time will change in unpredictable ways before they actually set foot on the field in a game.
What's the solution?
My favorite measurable is actually the vertical jump rather than the 40 time. Again, rarely will a player actually be required to jump very high from a standing position in a football game, but I think it measures explosive leg strength which is a much more valuable quality than straight-line speed. Every player on the field needs explosive strength. Every one of them. The running back needs to power through a hole. Every defensive player needs to explode on a ball carrier to make a tackle. Offensive linemen need to explode off a snap and push defensive linemen around. Defensive linemen need to stop the offensive linemen from doing that. Wide receivers need to explode past defensive backs.
Also, because the vertical jump is not as sexy of a statistic as the 40 time, players and coaches are less likely to falsely report measurements or engineer better results.
So, take that for what it's worth. Don't get excited over a sub-4.4 because it's probably not totally honest and may not actually measure anything worthwhile anyway. By the same token, don't worry about it when a receiver or a running back has a 4.6 40-time. No biggee. Give me a 36 inch vertical any day.
This is why I like Sam McGuffie and Julio Jones as prospects. Look for McGuffie's highlight films on YouTube. Impressive stuff. Jones just might be the #1 prospect in the country for 2008. We have an uphill battle to get him.