Thanks for the insights, you make some very interesting points.
My biggest problem right now is probably ankle joint extension.
Personally I am running purely biomechanical. I am not saying this is the best for everyone, but after recovering from a stress fracture which kept me out more or less for 2 years, I find that biomechanics work better for me, and it boils down to 2 primary things;
#1 The Pawback; to initiate the pawback you begin with the leg in front of the body (at flight phase) after the shin whips out from the forward knee drive. You contract the leg (the pawback leg) in a manner that involves a very quick pulling motion backwards and down; and you only contract at the very top 1/5th to 1/4th of the movement, after that you (after you have gotten the momentum of the leg to switch direction) you simply allow the momentum you created from the top of the pawback to drive the leg down. BUT YOU DO NOT CONTINUE TO APPLY FORCE THROUGH THE MOVEMENT, THE ONLY USABLE FORCE IS AT THE TOP, NOT AS YOU GET CLOSER TO THE GROUND AND ESPECIALLY NOT AT GROUND CONTACT. There are almost no braking forces this way. All sprinting actions are performed in this manner.
Here is the key to this point; Since you have already contracted the pawback leg when it was in front of you, by the time the foot hits the ground, you will get a stretch in your achilles which will then lead to a rebound and ankle extension. I see no way to apply any force at all to the track (when at top speed) because all force has been applied before the foot hits the ground. Once the foot hits the ground all forces are stabilizing and rebounding of the achilles.
This is strictly from a biomechanics book. Bear in mind that World Class sprinters may be a lot faster then anyone will ever get with this type of sprinting form. But the difference in my sprinting, and my training partners sprinting has been astronomical.
All actions in sprinting are elastic. And only require contraction to initiate whatever sprinting action you are doing, you don’t follow through.
Do I try to apply extra ankle extension or do I rely on stretch and rebound only?
The other primary action is the forward knee drive phase. (comes from the hip flexors!) After the pawback and support phase, the moment after the foot breaks ground contact, from the point that the foot is farthest behind you the knee is whipped forward forefully, and again the contraction is as dynamic as possible, meaning that you are only applying force at the very beginning of the forward knee drive. (or the beginning 1/4th of the movement)
When you combine this with arm actions, you are getting the basics of biomechanical/scientifically efficient sprinting.
The only problem is what looks like better form may not actually pan out in real life. I would say the two sprinters that really use the closest I have seen to this form to be; Maurice Greene and Darrell Greene. (football payer)
A lot of other sprinters technique looks dowright horrible, even those running under 10.1, when compared to this style.