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Re: Re: Re: Momentum and hip rotation.

Posted by: Jack Mankin (MrBatspeed@aol.com) on Mon Oct 1 23:05:11 2007

>>> Jack. With regard to the linear contibution I would use Babe Ruth as a prime example of why their is or at least can be a linear contribution.

The leg load of the inward turn is using the long stride of Babe Ruth induces more of an elastic pull on the body which when unloaded appears to contribute more energy to the swing. As the stride is finished, the energy of the CHPextends through the front leg as Ruth comes around to contact. The energy produced is so great as to cause Ruth to end in a cork screw position.

I do understand that the corkscrew motion takes place after contact. But I believe the resulting follow through is set in motion because of the energy Ruth generates which was initiated by his downward hitch, inward knee turn and long stride which is a version of the archers pulling the bow.

I would agree with you that stride length has to do with timing. But the greater the batspeed the more a Sosa or Bonds can use a longer stride, hitch, or other pre launch movements. And I think that we are fooling ourselves if we think hitters that lack the same batspeed and or swing quickness/ability can use those same preset principles and be as effective. <<<


After reading your post, I think we are on the same page regarding how the conservation of linear motion can aid in generating hip and shoulder rotation. If I read it correctly, you are contending that the body’s momentum obtained during the stride is conserved in the loading of the lead-leg to do work.

I think this explanation has merit. Your description for conserving linear momentum is similar to another resent post on this topic. That post used the analogy of a pole-vaulter’s linear momentum flexing the pole. The un-flexing of the pole aided in the height of the vault. In a similar way, the loading of the lead-leg from momentum developed during the stride promotes a stronger extension of the lead-leg that drives the lead-hip rearward and therefore a more powerful hip rotation.

These are very different concepts from those promoted by Lau and Yeager for how linear momentum induces hip rotation. They basically contend that as the lead-leg blocks forward body movement, the conservation of momentum causes the back-hip to rotate about the blocked lead-hip – like a gate swinging on a hinge. Soon, I will post a clip that illustrates why this theory is not consistent with the laws of physics.

Jack Mankin


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