Posted by: Shawn () on Wed Jan 26 11:08:35 2005

>>>You know Skilltech as a good example of the kinetic sequence with a softball/fastpitch example. In it you will find accelerations and decelerations of the swing, when and where. Like any sequence it acts in a sequential fashion. You can see the how the sequence works from acceleration to decelerations.
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> I definitely see the hips and shoulders decelerating and the bat being accelerated. The shoulders might follow through due to momentum, but this is after deceleration takes place.
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> >>> The whip affect is a biomechanical principle. It helps explain the kinetic sequence of the swing. Why it acts in a sequential fashion both through the acceleration and deceleration phases. It helps explain how momentum is transfered in the swing. I think you are to tied up in the hands coming to a stop to crack the whip, what about the hips decelerating??
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> """By the definition of his analogy, there is no transfer of energy to accelerate the bat around the swing plane until the shoulders stop. I would contend just the opposite is true. I would say that when the shoulder stops (105 degree position), the bat should have already been accelerated to contact – not just starting to accelerate."""
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> I don't know if I'm following what your saying. The shoulders slow down transfering their momentum to the bat. They might not stop completely even if it looks that way on video.
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> look at skilltechnologies.com down the free sports player, check out the softball kinetic sequence and we can further discuss accelerations and decelerations in the swing. <<<
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> Hi Shawn
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> You stated, “I think you are to tied up in the hands coming to a stop to crack the whip,” It is Dr.Yeager’s crack of the of the whip theory that is “tied up in the hands coming to a stop to crack the whip.” It is his quote that states, “If one were to attempt to crack a whip by rotating in a circle without stopping the hand, and therefore not transferring energy, the goal of cracking the whip would not be attained.” This is Dr. Yeager’s analogy for the swing – not mine.
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> I agree with him that to crack a whip or snap a towel, the hand does stop to transfer energy down its length as it uncoils. I believe that analogy does not apply to accelerating a ridged object like a bat. -- It is not the stopping of the hands (as he states) that transfers the momentum into bat speed. – It is the angular displacement of the hand-path that induces an angular displacement to the bat that transfers the body's rotational momentum.
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> Jack Mankin
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I went back and read the article. He is talking about cracking a whip and not the swing.

How you crack a whip and how you swing follow the same principles of momentum transfer, but they don't work the exact same way. The entire body is used in a swing and only the arm basically in the cracking of the whip.

If you look at the example I pointed out, you will see the accelerations and decelertion in the swing. You will se how the bat is accelerated through the actions of the kinetic sequence.

What Yeager is talking about is this kinetic sequence in the swing, how the momentum is transfered into the bat. He is talking about the block actions of the front leg.

It's interesting to note the even the arms slow down to transfer momentum into the bat.

This all comes together during the hook affect to accelerate the bat. Even if it's moving in a circular path, it's still being accelerated out or around. The knob points back towards the mass as the barrel is being accelerated out or around the mass.