Posted by: Teacherman () on Thu Mar 6 08:09:29 2003

Jack,
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> From our data we have found the if the timing is right, the position of the hips and torso vary from inside to outside. For our tests, we set up a tee at an ideal position for contact in the middle of the players strike zone. The player swings at the ball on the tee (which Major League Players do on a daily basis as part of their warm up routine).
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> With respect to the acceleration and deceleration in the forward swing, as the player swings the bat the hips slightly lead the sequence, followed immediately by the combined acceleration of the shoulders, arms or hands, and the bat. The hips reach maximum acceleration between 510 and 585 degrees per second of rotation, followed by the shoulders (upper torso) 700 to 900 degrees per second, followed by the hands/arms, 900 to 1150 degrees per second, followed by the bat release speed of between 1750 to 2300 degrees per second. Done effeciently, the hips reach maximum rotation (on a middle plate pitch) when the bat is perpendicular to the straight line from the pitcher. This means at hip rotation of 70 to 85 degrees of rotaton, the shoulders at this point rotate to approximately 65 to 80 degrees or rotation. If the shoulders for example were at 85 and the hips at 80, this would indicate that the tension (often referred to by many as torque)between the hips and shoulders, generated from the initial swing phase had been completely released and now the abdominals, which early in the swing were a conducting station the energy (torque) generated from the ground up, must now act to decelerate the uppertoso. This in an indaction that the power has been released.
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> If this occurs before contact, we see an athlete with an early peak in bat speed (before contact) because no more energy from the large muscles is left to be transferred to the bat. If an athlete reaches this point too early in the swing, the bat can no longer benefit from the "energy" generated during the swing. The athlete must now attempt to release a new source of energy to the bat, largely from the energy that has been stored in the wrists, provided that energy has not been released as well through bat casting. If you can imagine the amount of energy that is created as an athlete attempts to roll the wrists, we see a small deceleration of the hands, followed immediately by a spike in bat speed usually much higher than the previous bat speed peak.
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> If the latter occurs during the swing, the athlete, loses control of the bat and fights to maintain balance. This is evidenced by a significant side bend (over 20 degrees to the trailing side). To regain balance and not loose complete control of the swing, the athlete rolls the wrists to generate additional bat speed, quickly moving the bat and those distributed forces around the body (rotation not linear).
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> On an inside pitch, this "near locking" of the upper torso and hips occurs with the hips at 92 to 100 degrees. On an inside pitch, this can occur as early as 65 to 72 degrees. The shoulders should lag by approximately 5 degrees on an inside pitch and 10 degrees on an outside pitch. This amounts to less than an inch of seperation, but can be the difference between a pop up/weak grounder and a hard hit line drive. Baseball and softball are not games of inches, but instead games of degrees. Meaning the margin of error is much smaller than an inch.
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> However, the two most common problems we see in athletes are premature wrist roll and an over emphasis on back foot rotation (But the two problems are related and can cause numerous other problems). Athletes who prematurely rotate their back foot (making this an active instead of passive movement), have many problems during the swing. Don't get me wrong an athlete can perfect this technique and perform very well in a game, but they are exposed on many pitches and different situations. It has a major impact on timing and the sequence. I could go on, but I hope this answers your question Jack.
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> All of this data comes from 4 sensors, strategically placed on the athlete, which provide "objective measurements" and requires very little interpretation from me. We see the hips, upper torso, head, bat and bottom hand. We don't have to see the legs and arms to know the impact that certain positions of those body parts have on the body. The legs impact the hips, upper torso, which impacts the arms, hands, bat and head.
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> Thank you and have a positive day.
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> Zig

Zig

I've done everything you told me to do and the clips don't work. I called you number this am and no one answered. Where are you located? I'll have to try again later. Time zones may be affecting my ability to talk to you support team.

As far as your last comments is concerned, are you saying the arms can not impact the swing. And if not, why not a sensor on them. In the one clip I can see, it's very difficult to judge what the hitter is doing without being able to see the feet, legs, and arms.