Posted by: Ahmahtzyah Barrett (mahtbarr14@yahoo.com) on Sat Oct 13 16:16:57 2007

> Dr. Russell-
>
> You are one of the leading lights in studying the science of the swing.Thanks for the amazing work you have done studying bats/collision/trampoline effect,etc.
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> Bat companies are trying to make a buck and ruin the game and open,transparent meaningful data like yours and Dr Nathan's can help preserve the game.
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> While there are leading lights like you and Nathan and Adair and Bahill in many areas,there is not much agreement on how exactly the body produces a swing and how variable this can be.Lots of info and speculation,moreso in golf.
>
> Jack Mankin has done quite a bit of motionanalysis and other experiments and can speak to his findings.Skilltechnologies.com has done quite a bit on golf and hitting.Still this is not real peer reviewed science,nor is it well communicated across groups.
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> I personally like their "xfactor STRETCH" concept
> (see skilltechnologies.com) which starts to get into how the body generates,transfers and transforms momentum.Muscular force production is too slow to power the swing.Tissue elasticity and oreientation of bone/joint levers becomes very important in making momentum transfer as efficient and near instantaneous as possible with motor theory perhaps indicating that the swing should be optimized for "quickness" which might mean minimization of timing error from bathead "launch" (which needs to be defined) to contact.Theoretically this might mean the optimal combination of a short trajectory launch to contact traversed as quickly as possible with escape velocity of the bathead achieved right at contact. Apparently the major source of timing error is how the body programs the duration of the swing and these conditions minimize this source of maximum timing error.Momentum is hard to feel and has direction which may also make modelling difficult.
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> My recollection of Dr Nathan's assumptions is that he describes the bat turning about a point approaching and even coming onto the knob as opposed to staying 6 inches off.This is very important for swing "quickness" which is necessary for fastpitch softball and basebll,but less so for slowpitch.
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> Was this player slow or fastpitch ? CAn it be run as a quicktime clip ?
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> It also helps to have clips you can run forward and back as opposed to stills to get as many clues as possible about what the body is doing.This way you can get evidence based on reactive vs active motions.
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> I would say this player is way off the plate and has a long swing.The quicker swing would be modeled by Bonds,for example,who puts on the body armor,crowds the plate,does not bite on the outside pitch and is able to hook the handpath of his swing (whatJack calls BHT here)so it is quick,short radius AND keeps the ball fair instead of hooking it foul.
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> I would "guess" going into contact that Barry's bat is rotating about a point onto the handle of the bat which makes a HUGE difference to his performance.How to study this is messy.I asked Dr. Nathan and he wanted to stay away from the messy stuff except to make some assumptions about how the bat's axis of rotation might progress during the swing.
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> Bahill's assumption is just that max batspeed(and contact) should be about when the bat passes the front foot which this hitter demonstrates.