I cannot believe some of the things that have been written here.
AlSal is Full of SH1T as far as "sprinting knowledge" goes.
Sprinting and running are two different activities, mechanically--almost completely different.
Real sprinting can barely be maintained for 100m by the best of the best, such as Powell. All else, much of the 200, is very fast running. The 400 is all running, and no sprinting, or else you will suck. Sprinting a 400 is far slower than running a 400--same goes for the 200, slightly less emphatically.
Distance runners do not sprint--I would even go so far as to say that they CANNOT sprint. They just don't have the appropriate equipment, same as they can't do an iron cross.
Some of them can run very fast, and there is certainly a need to be able to accelerate in distance running--but not to "sprint".
Distance runners don't "sprint" to the finish...they run very quickly. The closest thing I have ever seen to actual sprint form from a distance runner was Jeilan last year, and my raving about his performance and form can be found here:
http://www.letsrun.com/forum/flat_read.php?thread=4203011&page=3
And again, it is not a disparagement of distance runners. Distance runners cannot sprint. When they try, they look like they're goofing. A fast distance runner could run a 12-second 100m, but if they tried to sprint it, they would go no better than 13 seconds.
AlSal either has no idea what he is talking about, or he does understand, but is unable to articulate it properly.
400m guys are very fast runners. Gay and Bolt can run very fast. The first time Bolt showed serious sprinting form was on the anchor leg of last year's 37.04 WR relay.
If...IF he can continue with that form...new 100m WR