This is Part 2. For Part 1, see Velocity = Contact Length / Ground Contact Time
I think we all agree Contact Length and Ground Contact Time optimization is a case by case example.
Traditionally, the maximum velocity is reached around the 60 meter mark as referenced from my 100 splits article.
The secret of Contact Length being anthropometrically determined is NOT the sole factor in determining longer accelerations and higher top end speeds (but it does help if you have the fast twitch fibers to go along with it).
If Contact Length was the determining factor, how do explain how both Usain Bolt AND Tyson Gay are able to accelerate up to the 65-70 meter mark?
Jon Goodwin from UK Athletics does a good job in explaining this in the video below (RSS and Facebook readers, click here for the video)