Dr. Peter Weyand of Southern Methodist University spoke at the Illinois Track and Cross Country Coaches Association’s Annual Winter Clinic on Saturday, January 8th.
“I think it was really great for Illinois track coaches to hear from one of the world’s leading authorities on the mechanics of high speed running,” noted Lisle coach Ken Jakalski, president of the Illinois Coaches Association, the group that funded Dr. Weyand’s visit.
Dr. Weyand gave two back-to-back presentations. The first presentation provided coaches with scientific insights on the mechanics of running speed. His second presentation provided the history as well as the current implications relative to the speed regression algorithm he developed with Dr. Matt Bundle of the University of Wyoming.
“I was really surprised that coaches understood that declines in speed were related to forces and not fuel supplies,” noted Weyand. “This suggests as complex as the details of motor control, force production and delivery are during sprinting, coaches are grasping the simple, informative and valuable take-home message that speed is all about hitting the ground hard and fast.”
Here's a very interesting video from the SMU lab: http://www.youtube.com/watch?feature=player_provilepate&v=RH8JYunGhWs
Clearly the amount of time on the ground is minimal. It should be noted that from the half-way point of the stance phase to toe off force drops off dramatically.
Therefore, push-off does not exist.