Posted by: JJA () on Tue Nov 2 13:31:53 2004

>>> This force creates a torque about the wrist joint, being the product of the force on the bat created by the top hand times the lever arm of that force, i.e., about 3 inches. <<<
> > >
> > > Hi JJA
> > >
> > > I would say the lever arm (center of the left hand to the center of the right hand) is closer to 5.5 inches. However, regardless of the lever arm measurement, tests show that 45+ mph bat speed can be generated by keeping the right-hand in a fixed position and applying BHT alone. This bat speed is generated independently of THT or any "flailing action" from a CHP.
> > >
> > > Jack Mankin
> > >
> > >
> > We're simply rehashing old material here, with neither of our arguments apparently convincing the other. I'll try two more arguments before calling it a day.
> >
> > 1. If differential forces on the bat are important, this would imply that the distance between the forces would be important for generating torque (like you corrected my mistake above). This is a basic physics fact. This would thus further imply that a Cobb/Wagner like split-grip, with more lever arm between the hands, would imply more torque on the bat and hence more batspeed. Since I think all of us would agree this is not the case, this leads to a contradication, and implies differential forces are not important.
> >
> > 2. Consider a modified one arm swing. Grip the bat normally with the bottom hand, but use an open top hand grip, with the bat resting in the palm and between the thumb and forefinger on the bat. This open top hand allows the bat to be supported but not allow significant forces to be transmitted to the bat. Even simpler would be a one arm swing, but this way allows the bat to be supported and thus easier to swing.
> >
> > This grip setup makes it virtually impossible to impart "top hand torqe" or "bottom hand torque". Yet go ahead and swing the bat. I would argue that even a novice could generate in excess of 80% of their normal batspeed with this technique. I can, and I'm certainly no John Elliot.
> >
> > This means that "top hand torque" and "bottom hand torque" can be only small contributors to overall bat speed.
> >
> > -JJA
> >
> > P.S. Incidentally, I'm not sure why this argument generates such controversy. It really isn't very important for a person to know how forces are applied to the bat. It certainly doesn't distract from Jack's cues on how to generate what he views as "rotational" mechanics. It's the difference between theoretical swing mechanics, and teaching a baseball swing. I think most of us are really only interested in the latter, whereas this is a discussion of the former.
>
> The fact that THT generates 3-4mph initial batspeed says it all. This defines its contribution to final batspeed.
>
> However, perhaps:
> 1. One can swing more accurately with this added speed.
> 2. This could add 15ft to a fly - a difference between out
> and homerun in many cases.
>
> Mike.

Mike,

Agreed. Jack and I simply disagree about the contribution of top hand and bottom hand torque to the swing. He believes they dominate the swing process, and I believe they are only small contributors.

-JJA