Posted by: Jack Mankin (MrBatSpeed@aol.com) on Fri Sep 17 13:41:03 2004

>>> Barry Bonds has an incredibly fast swing (1/8s). With such speed, conventional video (30 frames/s) is of rather limited probative value.

The question is:
Is there ever a point in Bond's swing where his back leg extends?

Yes. By chance, you can see it between frames 3 and 4 in the following:

http://www.usatoday.com/sports/gallery/bonds/flash.htm

Another important consideration is very strong upper body strength. The more forcefull the upper torso (shoulders and chest) initiation, the more forcefull the lower body (hips and legs) reactionary counter force. So, even if Bonds' back leg does not extend, it can be reasoned that just preventing/reducing intial backward rotation is a feat in itself.

As proof, sit in a swivel chair, suspend your legs, and quickly rotate your upper body in one direction. You will find the chair beneath you rotates in the opposite direction. <<<

Hi Mike

I agree with your assessment of upper-body to lower-body dynamics. However, I viewed the Bonds’clip a number of times, and I see the back-knee and leg rotating but I see no extension of this leg, as one can clearly see with the lead-leg. In fact, there appears to be more flex (or bend) of the back-knee in frame 4 than in frame 3. I also viewed 4 other clips of Bonds’ swing and observed his back-knee flexed rather than extended during rotation.

Jack Mankin