I always thought this guys SL bounds we're amazing...
http://www.youtube.com/watch?v=vJ0da_u6eLI
He might be a great high jumper and the bounds might look cool the way he does them but IMO it looks like he is actually using his quad for knee extension which is very bad way to train especially if your a sprinter...
In the front side mechanics of a sprint or a bound after the front knee passes forward the hip and hip alone should snap down pulling the leg back and under the body. The leg SHOULD go from bent to straight before ground contact and although it might look like it, this is accomplished with a relaxed quad and a relaxed and elastic knee, the snapping that comes from the hip makes the knee strengthen not active quadricp knee flexion - ie there is no kicking out in sprinting!
This is why I tend to avoid C skip type drills beginners because they will raise the knee (rather than point the knee) and then actively kick their leg straight and bring it down... it causes them to "look" more like a better athlete but it also reinforces terrible mechanics. Unlike the hamstring which does have a role (albiet minor - still mostly elastic recoil) in flexing the leg in backside mechanics the quadricep stays relaxed and should not be used for knee extension on the front side...
I could be wrong and maybe he is just that elastic that his leg straightens that early... but it sure looks like active knee extension to me...