Posted by: tom.guerry (tom.guerry@kp.org) on Fri Mar 7 10:26:10 2003

Jack,
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> According to Phil Cheetham, our founder and one of the country's leading biomechanical engineers, our findings show a direct relationship to the controlled increase in speed efficiently through each segment, ultimately impacting bat speed.
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> If the speed gain from the hips to the upper torso is in the correct range (not too high or low), there is an expectation of speed gain from the uppertoso to the arms and the arms to the bat.
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> For example if I get a speed gain of 200 degrees per second (dps) from my hips to my upper toso, I would expect to get a similar gain, 200 dps from my upper torso to my arms. I would then expect a large gain from my arms to my bat (800 dps or more). But if I release a large amount of energy during either or those first two segments, that energy cannot be transferred to my bat.
>
> Example: I gain 300 dps from hips to uppertorso, and gain 300 dps from my uppertorso to arms, I may only gain 450 dps from my arms to my bat, resulting in a lower bat speed. That loss is only 150 dps. But 150 dps is approximately 10% of the athlete's pre-contact bat speed.
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> Equally important to the acceleration of the segments is the deceleration of each segment at the appropriate time. If I cannot decelerate each segment effectively, I will allow that segment to reach a higher speed. In essence, we would call this a power leak.
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> The athlete with this power leak will appear to the naked eye to have a pretty fast and effective swing. But in our findings that athlete could be better if the athlete learned to control their body and the release of energy from one segment to the next at the right time.
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> Your best contact hitters (Tony Gwynn and others) would be efficient decelerators, not accelerators. It is their use of deceleration that allows them to reach high speed gains and make adjustments to the pitch they are thrown.
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> I spoke with Pat Murphy before the Holidays as we were getting ready to analyze some of his players and he said, "I wonder if it's bat speed or stability at contact the is more important to a hitter?" My response, "Stability." To which he replied, "I would agree. Sometimes I see my guys at the plate with one foot in the box and ready to go, while the other foot is getting ready to bail out. I keep telling them to just dig in and stand your ground, focing them to be more stable."
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> Jack, if an athlete has generated a significant amount of bat speed but cannot decelerate effectively, they will not be able to maximize that speed. In essence, they will have sacrificed control for the "appearance" of speed.
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> In our findings, it is not just the raw bat speed but the acceleration/deceleration of the bat and each segment before it, and when the bat reaches maximum speed during the forward swing that are important.
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> Most of the athletes we have tested had a significantly higher bat speed shortly after contact. This was related to the wrist roll, which occurred after the bat reached an initial peak in bat speed at an angle of between 30 and 45 degrees before contact. At this point the force which generated the first peak in speed is no longer acting on the bat to carry it through the hitting zone. (Power was lost through earlier leaks). The athlete must now try to impart more force to the bat to get it moving again. At this point, it can only be done by rolling the wrists, prematurely.
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> Typically, when an athlete reaches bat speed early, it forces a side bend to the trailing side. Remember, athletes stand in such a way that will allow them to remain in a good athletic position throughout their swing. This athletic position can only be maintained if the maximum amount of speed to the bat is released at the point (or just after) the bat makes contact with the ball. So if you see an athlete with excessive lean early or late in their swing, that is probably the point where the bat reaches a large peak in speed and as a result was at its heaviest weight.
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> There are many devices out there, which I am sure you are aware of that allow an athlete or coach to measure bat speed at a given point (typically in MPH). But nothing that allows you to measure the acceleration and deceleration of the bat and body (in degrees per second), except our technology. That is why I am trying to get the message out there to you and to others that we need to take a much closer look at what happens with the body and the segmental speed gains on the way to the bat.
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> Thank you for your question. I hope this answer is sufficient for you and others.
>
> Zig Ziegler

Zig-

I think it's good you are looking for hypotheses/models to organize your data and hopefully iteratively adjust how you collect data.

All this raw data is admirable,but not very relevant unless it supports the ongoing refinement and testing of hypotheses which can somehow be related to teachibng/learning/refining a good swing.

A lot of other work has already been done,so hopefuly the scientist/modelers you work with will be aware of this and limit the blind alleys you inevitably go down.

I would be interested more in how you explain your data and how it changes the data you will next want to go after,in in other words,get at the Why of it all.The why is important in getting better.

Some questions.

Nyman has said that for kinetic chain to work well,one segment needs to hook up to the next when the first segment is at maximum turning velocity.Can you measure this.Are the sensors placed in a way that you can see when the torso turns in relation to how fast the hips are turning.Is this discrete enough to be read by one sensor,or is it an action that works more gradually up the spine? I don't know what the literature says,but I'm sure ther is some.

Can you measure acceleration/deceleration with enough resolution to assess how this is related to efficiency of chain ?

In your description below,you talk about hip and shoulder "locking",is this when the shoulders catch up to the hips ?

Did you mean this happens at 65-72 degrees for outside(says inside) pitch location ?

Jack has said that for ballistic events,after "launch",only minimal adjustments to the trajectory are possible.

Adair has said that every swing involves translation and rotation.The early translation phase is active/caused by actions of batter moving bat,but once the rotational part is underway,the body is more or less just reacting to the bat,how does this fit ?

Jack has described what I interpret as a 3 arc model of the rotational part,hips/shoulders/bat.Can you measure these,how do they relate ?

Adair has described a tradeoff between batspeed and contact related to how far the axis of the rotation of the bat is from the sweetspot.The farther this is beyond the handle,the slower the bat,but the longer it is in the zone.

Looked at from the motor pespective,however,the shorter the path of the sweetspot and the faster the object traverses this path,the lower the timing error and power hitting is essentially a timing task,so does Adair's hypothesis hold water ? Is there really an inescapable tradeoff ?

You have described more 'separation" for the outside location.Why is this? Is the body like a torsion bar? If you load the hands further back for the outside pitch,does this just create more "load" so there is more drag,or do you actively separate more ?

Epstein has talked about adjusting for off speed stuff by flexing the back leg more.This could make the swing longer by increasing the upward swing gradient,or it could delay how weight shift is used to trigger hip turn driving shoulder turn.Can you look into this ?

These are all just brainstorming stuff that would need real scrutiny by a science/engineer type before setting up real hypotheses and models and how to test them.They are really too raw to do much with as far as any real application.

How are you working to make sure the data is meaningful and "safe" to apply ?