Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Jun 13 12:09:51 2008

>>> Jack,

I'm not defending Teacherman, I don't need to. I have learned a lot from you and your site and I have also, learned from Teacherman, as well as Epstein and others.

IMO it is more of a "feel" issue. The shoulders are going to rotate they ultimately have to. The bypass is more of a feel. In the kids I have worked with, when they rotate the shoulders to power the swing the hands and bat are always left behind and the swing looks slow and they tend to pull off of the ball. But I will say when they do get the bat there on time and square the ball they have a lot of power.

I have found that when shoulder rotation isn't actively trying to be acheived and the focus is on the bat being turned in the hands to the ball. The shoulders stay closed longer allowing the hips to turn more, creating stretch and tension in the torso, giving the hands a solid platform to be launched from.

When I work with my son I mostly work on the hands turning the bat rearward (PLT) and then maintaining the arc of the bat to the ball, by the bat turning in the hands. Everything else seems to fall into place.

This disscusion could go on forever. Again I think it is a "feel" of the shoulders being bypassed.

One last thing. When I ask my son what he feels in his swing when he is hitting good, he just says "effortless power".

Graylon <<<

Hi Graylon

As you know, I defined the use of the hands and arms that induces the rearward acceleration of the bat prior to shoulder rotation as Pre-Launch Torque years ago. Through this portion of the swing, I agree with you and Teacherman that shoulder rotation plays no part in the bats acceleration. I have pointed out many times the importance of maintaining the inward-turn position of the shoulders until the bat has been accelerated back to the optimum launch position before activating the muscles that generates shoulder rotation.

After years of discounting PLT and THT, it is good to see that Teacherman finally understands the importance of mechanics that accelerates the bat rearward. What he still fails to understand is the mechanics that apply torque and the pendulum effect (CHP) from the launch position (bat in the plane behind the head) to contact.

It appears he does acknowledge that the muscles of the arms alone cannot supply the power required to attain great bat speed and therefore must come from the larger muscles of the legs and torso. However, his theory that energy generated from hip rotation somehow “bypasses” restricted shoulder movement and is transferred directly to the forearms is bio-mechanically impossible. Although the hips do cock open during PLT (as you pointed out), there is no transfer of the hip’s energy to the arms to aid in applying PLT.

PLT is induced from torque supplied from the rolling action of the hands and forearms as you and Teacherman describe. However, PLT is a low energy movement that attains only a small fraction of the bat speed attained during the entire swing. Once the bat has been swept back to the launch position from PLT, a much stronger form of torque (THT) is induced as the energy supplied from shoulder rotation is activated.

Graylon, as I am sure you have found, describing these mechanical concepts with the written word is iffy at best. This weekend I will work up a video clip that may make the importance of these mechanics easier for readers to grasp. In the meantime, I agree with you that most of the shoulder rotation of most batter’s is wasted and the bat is left dragging in the contact zone. Due to loose linkage and lack of rearward bat acceleration, these hitter’s rotate the shoulders but the angular acceleration of the bat does not stay in sync with their shoulder rotatio. --- Below is a post from the Archives I wrote on this topic.

<a href="http://www.batspeed.com/messageboard/23045.html">Pulling the ball</a –


Jack Mankin