Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Mar 2 16:53:58 2001

>>> Sorry for the `miss' on the title, I was a little too hasty in hitting the `Enter' button, before finishing an additional comment/question relating to BHT. As stated above, we have been concentrating on the basics of rotation, without incorporating THT or BHT. After watching the replays of my son's swing in slow motion, I saw what appears to me to be a `secondary' increase in bat speed that occurs after the bat crosses the POC (I have always tried to get kids to hit the pitch before it reaches the front edge of the plate). He is a lefty batter, and at that time, it appears that the `pivot' point for the bat is between his hands.

Could this be just due to the momentum of the bat? Or is it possible that this is BHT? <<<

Hi Ken

"Could this be just due to the momentum of the bat? Or is it possible that this is BHT?" --- Ken, you have just touched on a subject that has been a source of great controversy for some time. What is the energy source for the added bat-head acceleration as the bat nears contact? I have stated that the energy source is "torque" derived from the hands applying force from opposing directions (lead-shoulder pulling the bottom-hand back toward the catcher as the rotation of the back-shoulder drives the back-hand forward). Other noted authorities discount torque as a factor. They claim the added bat speed is from the "whip effect" derived from the transfer of kinetic energy or the "conservation of momentum."

For those that discount torque as the major factor, I would ask that they address the following question. --- Suppose I am a right-handed batter and I were to take the palm-up/palm-down hand and body position of a batter at contact. Let the contact point be a heavy bag. Now, without moving my right (palm-up) hand, I push my left hand forward causing the bat-head to arc away from the bag 70 to 80 degrees. Without moving my right hand, I then pull on the knob-end of the bat with my left shoulder and arm. --- If the bat-head was accelerated 35 to 40 (or more) MHP back to contact, would the energy source for that acceleration have been developed from the "whip-effect" or from "torque" being applied??

Of course I believe in the laws of physics, but I also believe some of those laws have been misused as related to the baseball swing. One of those misuses is equating the whip effect to bat-head acceleration. Let us take a closer look at how the tip-end of the whip is accelerated. --- As the whip handle accelerates, so does the mass of the entire length of the whip. The body of the whip is limber and it's diameter gets ever smaller down it's length. So, as the handle stops, the conservation of energy and momentum cause the whip's body to uncurl forward. The conservation of energy causes the energy of the uncoiling whip to remain fairly constant. But, as the length uncoils, that constant energy source is doing work on an ever-decreasing mass. As the mass approaches zero, the tippet exceeds the speed of sound.

There is no way you can equate this whip effect to generating bat speed in the baseball swing. Not only is the bat a rigid object, it gets heavier (not lighter) down it's length. --- Having a player snap a towel to develop his baseball swing mechanics is counter-productive.

I also think that many of the laws governing the "conservation of momentum" are not being used correctly when applied to the baseball swing. Many coaches believe that if the batter extends the bat knob at the pitcher (or the ball), the bat's momentum will cause the bat-head to snap through as the hands slows to a stop. --- Similar to a goat hitting the end of a rope. --- This is also not a correct analogy. Once again the bat is a rigid (not limber) object.

If it were true that the momentum of a rigid object (like a bat) would cause the bat-head to "snap around" when the knob slows or stops, then please consider the following. --- The tip of an arrow traveling at 300 fps stops within 2 to 3 inches upon striking the target - why didn't it snap off. If linear momentum were converted into angular displacement, the arrow would snap. It does not snap because the momentum is directed linearly down the shaft and drives arrow into the target. The same is true for the bat. The momentum is directed down the shaft and the energy is expended into the hands.

So Ken, if your son is developing bat speed from a source other than an angular hand-path -- that source is torque.

Jack Mankin