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Posted by: tom.guerry (tom.guerry@kp.org) on Sat Jan 3 17:57:17 2009


This may be why you are confused.

In the torque video linked in the other thread this month with the "pathfinder", Jack is
isolating the torque component of the swing.

I think Jack has the best mechanical model of the swing for explaining the advantage of
"rotational mechanics".

There are two mechanical components to the swing, handle torque and the
CHP/pendulum that connects the rotating body to the bathead.

The swing JAck recommends is a synergistic blend of these so that the torque of the
handle works to add to the batspeed/bat quickness of a CHP that remains connected to
the turning body from initiation/launch until contact.

Each of these components is "rotational".

Jack's torque demo this month is a "torque only swing" which is a typical low level "linear
swing" because it casts/disconnects from the body and uses only torque to power the

This is a casting swing for the purpose of eliminating the contribution of the
CHP/pendulum component for demonstration purposes.

When you actually want a high level swing, you need to apply handle torque while at the
same time keeping the hands back at the armpit/back shoulder which is the purpose of
the thumb drill.

Given the nature of the physics governing these kinetics, if each component contributes
equally to batspeed, the result would not be a doubling, but an increase by a factor of the
square root of 2 or a multiplier of about 1.41.

Here are a couple of old related posts from Nov 2004 where there were a number of such


Throughout my writings and in the video, I stress that a CHP is developed from keeping
the hands back at initiation and allowing body rotation to fling them onto a circular path.
Torque applied at the handle is not a factor in developing a CHP. However, it is a major
factor (along with that from the CHP) in generating bat speed. If you don't have the video,
I would strongly recommend that you go back to square one and study the swing
mechanics and bat speed research page.

In the video I demonstrate that a CHP accelerates the bat-head in the same way that
swinging a ball on the end of a string accelerates the ball in a circle. As long as we keep
our hand in a circular path, the ball will continue to accelerate in a circle. But once the
hand-path straightens (more linear) the angular displacement rate slows.

I have always defined linear mechanics as producing a more linear hand-path that results
from extending the hands toward the ball instead keeping them back at initiation. I have
also stated many times that the force acting on the bat from a circular hand-path is
directed lengthwise (linearly) down the bat ("like swinging a ball on a string").


Hi All
> >
> > JJA contends that since I have stated that about 50% of the bat speed comes from
torque (THT & BHT), and since rql acquired about 65 mph with a one-handed swing
(mostly CHP - little to no torque), this means a batter using both CHP + torque should
generate 130 MPH. He implies that this is a paradox that must be answered if torque is a
major factor in generating bat speed.
> >
> > With JJAs line of thinking, I would point out that there is an equal paradox to be
answered if we contend that a CHP is a major factor in generating bat speed. If a batter
(as in Nicks clip) can attain 65 mph by extending the hands in a straight path (mostly
torque little CHP), and if bat speed from a CHP is a major factor, then this batter should
be able to attain 130 mph if he took his hands in a circular path.
> >
> > Jack Mankin
> >
> > Tom Waz and Mike Myers, need your help. You guys can better answer JJAs paradox
than I. (I was considering F=mVV )
> >
> > Jack Mankin
> >
> Jack,
> I was thinking more of KE = 1/2(MVV) where KE is Kinetic Energy. The problem with this
equation is that it is for objects moving in a straight line. There is a formula F = MVV/r
which oddly enough is for objects rotating in an arc. In both cases, doubling the energy
or force only increases the velocity by 1.41 (the square root of 2). So if either force could
accelerate the bat to 65 mph their combined effort would result in a velocity of only 92
mph not 130.
> I would like to have spent more time to verify that these equations apply to our
example but didn't think I could get to it for a few days and didn't want the thread to die.
> I'll give you an update if I find any faults in my reasoning over the next couple of days.
> Tom Waz


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