Posted by: tom.guerry (tom.guerry@kp.org) on Wed Apr 11 12:06:54 2001

Jack et al-
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> > What do you think of the physics principle discussed in Max's reply to Jack from long ago in "Best of Max #1" ?
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> > http://setpro.com/NEWWEB/best%20of%20max00.htm
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> > It makes sense that the thing that demands energy from the torso is torquing the center of mass of the bat out of the arc of the handpath.The best time to do this is when the torso is at maximum energy(roughly equivalent to maximum angular velocity).The most efficient transfer would be by extending the center of mass quickly once it leaves the arc of the hand path(it has to be on plane by this time, too).Strong arms and forearms would seem important in assisting this torquing between the hands.
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> > The hooking handpath allows the hips to turn the torso more before the demand for transfer is made which keeps the bathead in longer and the ball in fair territory plus lots of batspeed.The middle away pitch starts energy transfer sooner,but with a wider radius and tophand torque assisting in faster extension of the center of mass once it leaves the arcof the handpath. M.D. the split grip seems to mess with the leverage of hitting off the end of the bat like choking up but worse.The grip when I tried it always seemed like the hands were doing 2 different things/pull/push,but separated instead of smooth acceleration through the swing.Tom,I don't follow exactly what your saying could you rephrase the thought for myself if possible.rql

rql-

Thanks for trying to stick with my thoughts.Here's the long version.You might also try plowing through the best of max and see if any of that rings a bell.Let me know what further confusion I'm creating.

This is difficult to express because the ideas are non intuitive.In your case from your story,you figured out through long,painful trial and error how to lean back to keep the inside pitch fair,and I'll bet you gained power rather than lost it when you did this.You figured out the right contact point which was not what you were expecting or what anybody told you.Jack has explained some of the physics that apply here,and if you understand that,that knowledge might allow you to discover other things that give you an edge in coaching or hitting.

Usually the best thing we can do in instruction is teach good tempo,teach getting into the best positions in the best sequence,then try to put it all together all at the same time with the right mental approach.These positions and sequences and tempo are harnessing basic/pure physics principles and are very complex because of timing and the complexities of human tissue interactions and motor control-hard bones,stretchy tissues,brain wiring,etc.

One of the least intuitive principles is the one that accounts for most power/batspeed/quickness of hands,and that is transfer and conservation of momentum.One of the simplest examples of this is the whip.I am not a basic scientist,so my simplification may be inaccurate so others can feel free to correct this.When you crack the whip,you give the system momentum by snapping the handle-you move the hand back and forward then stop it suddenly.This imparts a given amount of momentum to the system which must be conserved as the motion goes forward without significant additional forces being applied.The whip is long and tapers.the product of mass x velocity(momentum) is conserved and the less mass that is in motion,the faster it has to move and the further away it is from the handle,the more leverage there is.As a result,the tip of the whip can "crack" as it exceeds the speed of sound.

Adair believes this is the main source of power for the swing.Best of max 1 states that momentum should move from one link in the "kinetic chain" to the next less massive link when the first of these links is at maximum momentum(maximum turning velocity of hip or torso in the case of the swing).This means you want to transfer momentum to the bat once the torso is at maximum momentum/turning velocity/energy.This happens over a window of time when the hips are transferring the large momentum of the lower body upward as hip turn decelerates.A visual signal that this is underway is when the back foot drags behind the front which it will do (if it is no longer bearing much weight) as an "equal and opposite" reaction to the twist going upward from the hips to the torso.Momentum will be best transfered by rapidly stopping hip turn(like the whip handle) and is over when the hips go"up".

So some time between foot drag and the "up",you want to transfer as much momentum as possible to the bat.Jack has been the first to point out the importance of "transfer mechanics" and how they are in part dependent on a circular handpath.The other factor that is key to "demanding" that the torso transfer its momentum to the bat is forcing the bathead(center of mass of bat for modelling purposes)out of the arc of the handpath.Best of max goes on to say that not only is the timing of bathead extension important(when torso is at max energy)but the faster it gets to extension after it leaves the arc,the more efficient the transfer.

This momentum transfer is a huge force that develops quickly and takes the body along with it after a certain point.So it's hard to say how much control various body parts have,but at some point you are just hanging on to a launched projectile-the bat.

So to summarize,we need to get maximum energy in the torso and get the bat on the plane of the pitch,then we want to transfer the momentum to the bat making it turn as fast as possible.We do that by extending the bathead.

Now we have to talk about extension.The energy is going to go into the bat and arms,but the goal is to turn the bat.If extension happens by the hands getting further away from the body,energy is used to push the bat knob out,not turn the bat(the "bad" kind of inside-out swing).As Jack has pointed out,extension needs to start by leaving the hands in a circular path and "torquing" the bathead out with the hands.This can eventually be followed by extension of the hands without siphoning off too much energy pushing the bat instead of turning it,but this kind of extension of the hands away from the body/center of rotation is desirable before contact only on the outside pitch.

So now physics is telling us to get maximum body energy in the torso,then transfer it to the bat by extending the bathead out of the arc of the handpath as rapidly as possible without letting the hands get away from the body until near(outside location)or after(inside) contact.If you don't let the hands get away fom the body,there are then Jack's 2 ways of getting the bathead out-turn the body with a circular handpath(steering wheel knob demonstration) or torquing the bat about a point between the two hands or both.

Now the question is how much of this is really under control.This is a ballistic(projectileproducing) activity too fast for conscious control,so not much of it is under conscious control.Instead you can learn to recognize a pitch,match it to a learned and stored motor program and execute the motor program without conscious interference.These programs are built of little pieces each of which has alternatives that can be plugged in to slightly alter some aspect of the swing shape or timing.The fewer/more similar the programs the quicker the match and the less reaction time needed.Of course,you still need good plate coverage.The shorter the trajectory to the ball and the faster you complete the trajectory,the less the timing error.The better you match the plane of the pitch,the better the chance of contact and the better batspeed/energy is transferred to the ball at collision/contact(as opposed to the swing chopping across the plane of the pitch).As you know,you still have to have the right "bat angle" to keep the ball fair.

Even though these motor programs are automatic,it would still make sense that good arm/wrist strength would contribute to getting the bat torqued to extension faster and with more of a timing window(as well as fixing the handpath to the torso when it first starts turning).A smooth/unbroken kinetic chain through the body with good upper and lower separation would also help.A stable axis from launch to contact is important as pointed out by Jack.

Now lets get back to hitting that middle in pitch hard and keeping it fair.What kind of motor program/adaption/swing shape is best?Jack describes the key as "bottom hand torque".Paul Nyman describes this as "the hook at the end of the swing".You figured out from trial and error location of the contact point with tee work that if you lean back,you get rid of the dead pull/hitting around the ball so everything is pulled foul.Some people learn this as hitting the inside of the ball or inside-outing it(in a "good?" way).Physically/biomechanically what is happening is that you are tightening the arc/curve of the hand path as the swing proceeds.This is combined(?control of motor program by "feel" in hands?) with continuing to turn the hips longer than on the outside pitch.The result is that more of the handpath is traversed before the hips decelerate and the torso is energized, and the hands stay in longer.Then they torque the bat out later in the handpath and with great acceleration.The bat angle keeps the ball fair with high batspeed(power)by the time of contact.Jack describes this as pulling back the knob with the bottom hand via its connection to ongoing front shoulder turn which is pulling the arm back toward the catcher.

On the outside pitch,hips brace up earlier into the handpath,the handpath has a wider radius and ongoing "top hand torque" assists the bathead in extending fast.This combination can create almost as much batspeed as pulling the inside pitch.The ones who do this well hit this ball further out front than if they keep the same swing radius just lletting the ball get deeper,so they can get better elevation and more distance hitting the outside pitch more toward the pull field.

Clear as mud ?