Posted by: JJA () on Sun May 9 19:10:12 2004

I would personally like to see some more testing for the torque hypothesis,especially what Jack describes as "THT".
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> I am not a scientist. I am what Paul Nyman would call a voodoo scientist.I have no formal scientific training and do not think well abstractly/mathmatically/however it is that Adair types think.
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> With regard to the swing,I do think it still helps to have an accurate picture in mind to match up with the feel you get for the swing when it comes to learning to master the swing.The more reality based the "cue"/swing key,the better the skill acquired or perhaps the more successful the teaching, it seems to me (still just a hypothesis that would be good to test).
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> I would really like to see other interested parties do the test,but I have trouble getting science types interested.We have heard Jack's Adair story.We can see much of Nyman's interpretations,but it is still hard to see exactly where Jack and Paul really agree/differ because an adequate communication between the two has yet to happen.
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> I have personally corresponded with Bahill (of Watts and Bahill fame) and Nathan (of bat testing fame) and neither is particularly interested (surprising to me) in how the body works to produce the swing.Bahill likes visual system and collision stuff.Nathan likes bat composition and collision stuff.They each make some assumptions about the body,but they do not seem to be in accord with what the body actually does.Neither seemed very interested in how "hooking" of the handpath might effect batpath/batspeed,for example.As Jack mentions,Adair makes assumptions about the need for forward motion of the body that do not seem to be what many power hitters often do.Adair still has not revised/retracted this in the 3rd edition,so he must feel that this assumption is still adequate in calculating what the great power hitters do (what Adair describes as a "tractable model").It makes a voodoo scientist like me uneasy when the model does not line up with the reality I "think" I experience and which seems born out by video analysis,that being that the forward motion does not "appear" to be as Adair describes.Maybe I'm just superstitious.
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> I am particularly interested in variations and constants across skills.It seems to me,where possible,the human body develops certain reusable units of motor ability/solutions that can be cobbled together in different ways to solve different "motor problems"/challenges.For example,arm loading sequence seems similar to me between the overhand throw and hitting.Body rotation/xfactor/xfactor stretch seems similar between golf and hitting,etc.Jack's "golf club drill" seems to demonstrate to me a different type of connection between the torso and the clubhead/bathead resulting in different acceleration characteristics in golf vs hitting.
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> My voodoo/layman's way of making sense/reconciling the varying "transfer mechanics" hypotheses is that Jack is describing something important about handle forces during the initiation of the hitting swing which he calls THT.This does not necessarily mean that the hand itself(or smaller limb muscles) are generating the majority of this force,perhaps they are mainly transmitting forces from bigger muscles.The feel I have in golf seems very much like the "double pendulum"/iron Byron type as I have mentioned here before.Paul Nyman has been nice enough to link/post some descriptions of this,see:
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> http://carini.physics.indiana.edu/E105S99/swing.html
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> and
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> http://www.setpro.com/forums/showthread.php?t=5799&page=1
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> Video in golf will often show the "hinge angle" become more acute on the down swing as suggested by the double pendulum demos.However,as Nick's overhead shots show,the hinge angle for hitters stays around 90 degrees or slightly more or less until unhinging.Is some other (?torque/handle) force resisting the narrowing of this hinge angle to improve the acceleration characteristics of the swing for the hitting task ? Or is this just a result of the different masses of the 2 links,etc ? The hinge angle can also be seen in the Griffey motion analysis at peavynet.com where Griffey starts at about 90 degrees preswing and gets to about 110-115 degrees and stays there until unhinging begins after the "lag" position.(long download from peavy)
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> Unhinging needs to wait until untwisting/uncoiling/momentum transfer has begun.In golf it seems like you do this by the narrowing then unhinging late,but in hitting,it feels to me as if the bat head is being forced out in the preswing and at initiation with video showing a more constant hinge angle rather than the golf type dynamics.
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> BHT seems to me more a pure rotational/whip force approaching contact due to the bottom hand/lead arm/scap shaping the handpath with the top hand more along for the ride.Confirmatory/rejection testing would be nice.
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> Now these are just a layman's feel with no experimantal back up,but may be useful in generating hypotheses to test or crafting "cues" that may improve instruction by being more closely related to physical reality.
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> I wish the scientific process would play out and have others generate/test the apparently conflicting hypotheses that are now supported mainly by belief.It seems odd that more scientific types do not pursue this particular area.
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> Unhinged Tom

Sir,

Your points are 100% right on. The difficulty for the scientist like myself is to try to convey the essence of an incredibly complicated constrained dynamical system called the swing. Coordinate systems, Euler's equations of motion, d'Alembert's principle and many other graduate level phyics principles are in work here that are difficult to convey without mathematics. My wrist elongation explanation was an attempt to explain something that everyone could understand, but without being overly rigorous. The attempt was to point out that Jack's experiments certainly don't PROVE his contention that torque is being applied to the bat. Hopefully he has additional data, experiments, or analysis that cast further light on his hypothesis.

The right answer is, as you pointed out, getting actual data. In principle, it's easy to do. I have lots of experience in doing similar things for aerospace systems. Why doesn't anyone do it? One reason, money. To do it right, which would require precision instrumentation, several representative players (hopefully big leaguers, college players, all the way to little leaguers), a few weeks to really analyze the data, would probably take a minimum of $25,000. Certainly not a lot, but I'm not independently wealthy.

Unfortunately, the market for baseball is small compared to golf. Only a few kids and a few big leaguers take lessons from professional instructors. In comparison, millions of adults take golf lessons. Thus, there is lots more money poured into golf research compared to baseball.

-JJA