Posted by: Jack Mankin (MrBatspeed@aol.com) on Sat Sep 10 10:53:35 2005

>>> Reread your article stated below, in your response to DBC. It raises an interesting question that I've debated for some time now.

You'd stated "With many players, the top hand is by far the most dominant hand".

My question is, which hand/arm provides the most power during a "proper" rotational swing: the TOP or the BOTTOM?

I assume it's the bottom, for mechanics/energy transfer linkage reasons. Also for the final BHT, once the batter is at 105 degree position, when the bottom hand torques the bat around the "stationary" top hand.

It's interesting to wonder WHY so many folks would hit with the reverse hands, as you'd stated above, if this is the case.

I'm right-handed, but bat/golf left-handed, as it "feels" right for my right hand to motor the bat/club through to the ball. And, when we've played non-competition "fun" parent/child games & the parents must bat opposite, when I bat right-handed, it just "feels" normal that my rookie left arm is providing the power to hit the ball, & the right hand is merely "along for the ride".

HOWEVER, if I'm hitting infield practice with my team, & I hit 1-handed, then I'm using my right hand in a "forehand" (to use a tennis analogy) swing, rather than the "backhand" swing I'd normally use when I bat as a leftie. And, as far as tennis goes, I have much more power using my right hand in the forehand, vs backhand, as likely 99.9% of right-handed tennis players do.

So here's another question:

The 1-handed hitting analogy: is this because it's likely more or less a LINEAR swing, vs rotational, and in this case, it makes more sense to use the dominant hand in a forehand swing?

I think this must be part of the reason. As a rightie swinging the bat left-handed, it feels like everything is driven by my dominant right arm, with the left arm as secondary source of power in a more "subdued" position, ie, in the slot following through. In this case, hitting left-handed would make more sense to me.

Regards,

-SJD-

PS - Jack, love the site & discussion boards. Between that, & ordering/studying "The Final Arc II", I think I've learned more about hitting in the last 4 months than I did for years playing competitive ball. Great work! <<<

Hi SJD

Your post raises some interesting questions and concepts that need to be clarified. I think discussing the dynamics of how a bat (or tennis racket) is swung one-handed vs the two-handed swing might clear up some of the confusion. Findings we obtained from tests we ran at a physics lab should help.

Professors at the lab determined that there were two physics laws that governed the bat's rate of angular displacement (bat speed). We can discuss later the more technical definitions of these laws, but for this discussion, we will just refer to them as "the pendulum effect" and "torque." The professors now needed a way to determine what percentage of the bat speed was generated from the pendulum effect and how much was derived from torque.

By attaching a steering wheel knob to the bat we could eliminate torque from being applied to the bat from the wrist when swung with one hand. When the wrist un-cocks during the swing, torque is applied (little-finger rotating inward/ thumb rotating outward). Swinging the bat with the knob eliminates torque from being applied.

The results of these tests with a regular bat and with the knob attached were quite interesting and may answer some of your questions.

(1) We found that swinging a regular bat with one hand produced a more efficient pendulum effect of the bat-head than when both hands were on the bat. The single wrist allowed the bat-head to be rotated freely from the pendulum effect (acting like a hinge). Adding the second hand to the bat greatly restricted both the range and freedom of rotation of the bat.

(2) We found that for a hand-path length of about 24 to 26 inches (average two-handed path), swinging a regular bat with one hand produced about 25 percent more bat speed than was obtained with the knob on the bat. This means that torque supplied by the wrist action was a significant factor in the one handed swing. Whereas, the restrictive range of wrist movement with both hands on the bat meant torque was mostly supplied by the push/pull action of the forearms in the two-handed swing.

(3) We also found that swinging a regular bat with one-hand in a longer and wider path (about 36 inches) produces bat speeds approaching an average hitter's two-handed swing. -- Note: For a given rate of angular displacement, velocity produced from the pendulum effect increases by the square of the radius. In other words, increasing the radius of the hand-path by 10 %, increases the angular velocity of the bat-head by 20 %.

SJD, let us apply what we learned from the above study to your tennis analogy.

(1) Whether swinging a bat or a tennis racket, a CHP is required to produce the pendulum effect.

(2) The "forehand" swing produces a much wider (greater radius) CHP than the "backhand" swing.

(3) The two-handed tennis swing produces a shorter and tighter CHP but greater torque is applied from the push/pull action of the forearms than can be supplied by a single wrist.

Jack Mankin