Posted by: tom.guerry (tom.guerry@kp.org) on Wed Aug 9 21:45:02 2000

I think the posts in this thread are missing Jack's point. The keywords are "other than their contribution to shoulder rotation." He isn't saying the lower half isn't contributing, quite the contrary.
> >
> > "However, I have to believe that if my body, "from the armpits down" were somehow encased in concrete, I would generate significantly less bat speed."
> >
> > Absolutely. Because the lower half could not influence shoulder rotation. This would be true regardless of what energy-transfer theory you subscribe to. I have to assume you really meant from the waist down, since encasing it at the armpits would also stop torso rotation. sorry...maybe i misuderstood & i would like to clarify a few things...jack, you previously said of the kenetic chain:
> > "I would really like to have a clear definition of the "Kinetic Chain......... It sounds like a new way of stating the old "crack of the whip" theory." ....now this is my understanding of the K.C.....hips 1st, generating x amount of energy...then shoulders, generating y amount of energy...total energy so far is x plus y...if arms were represented by z, then by the cummulative enerhy generated by hips, shoulders and arms would be x plus y plus z..i won't continue with hands since i'm out of alphabet....sorry my algebra isn't much better than my physics, but jcck, steveT tom.guerry, et al....do i correctly understand the kenetic chain? ....because jack, if i originally misunderstood you, and if in fact you are saying that indeed the hips, etc are contributing to shoulder rotation (which the "accumulated energy" continues to arms, etc), then you are in fact saying they contribute WHAT? energy that gets "passed along",THAT'S WHAT, right? and is that not the KENETIC CHAIN?...pardon my science & algebra & lack of the literary prose of the distinguished BLACK HOLE LEXCIOGRAPHER....respectfully, grc.....

grc et al-
This is the way(layperson's way) I conceptualize the kinetic chain,most of which is my interpretation of Paul Nyman's ideas.Please feel free to correct/comment on these concepts.As discussed at setpro regarding pitching(most recently in the one footed whip cracker thread),the kinetic chain delivers power by sequentially transferring momentum from the slower more massive parts of the body to the smaller(faster) mass parts.The ground up development of this power is somewhat similar in hitting and pitching to a point,but then the principles of how energy is transferred from the torso are quite different for these two skills.Jack's work is the first I know of that clarifies these principles of "transfer mechanics" and how they apply to hitting.As Jack points out,the bat is not a limber object like a whip or a towel or an arm,so the way you transfer energy from the torso is very different for a bat on the one hand and the ball on the other,even though both are ballistic motions.
I consider the ground up generation of power similar for both activities.The legs turn the hips.the torso is connected when the hips are at maximum angular velocity,then the hips are decelerated(stopped) sending their energy up into the rotating torso(creating the "up" or thrusting of the hips commonly seen just before contact).This is an action that has been termed "rotational whip by some.The necessity of a short swing radius dictates that rotation should be around a stationary axis for hitting as opposed to a moving axis for pitching.
In the case of throwing,transfer of energy from the torso is primarily accomplished by whipping the arm/forearm/hand powered by the unloading of the scapulae which moves the shoulder socket in a nice arc.
In the case of hitting,Jack has demonstrated nicely that transfer is via creating a circular hand path and torque by positioning the arms so that the shoulder(torso turn)drives the hands in a circular path while the hands turn the bat about a point between them driven by the arms connection to the shoulders.Energy can not be efficiently whipped through the arms to the bat as is the case with throwing a ball.As the bat swings out,inertia of the system increases,so by conservation of momentum,the shoulder/torso turn slows,but this should not be mistaken(as it often has been)for the intentional slowing of the shoulders in an attempt to whip energy into the arms.The shoulders should be kept rotating while the bat is launched,then the bat overtakes the shoulders and pulls them around on the follow through.The circular hand path and torque need to be maintained until contact for best results.
In summary,both activities require a kinetic chain.In the case of throwing the kinetics are mainly whipping,in hitting, rotational whipping drives the torso,but then energy transfer is via torque and a circular handpath.