Posted by: JJA () on Thu May 6 21:34:59 2004

> >>> Thank you for your response. However, I thought the purpose of your original experiment was to show that torque applied at impact generated significant bat speed. <<<
>
> Here's your quote:
>
> "As the bat-head accelerated to the bag, it was evident that torque was a major factor in generating bat speed. "
>
> If I read your response properly, it appears you are saying that you should actually apply the torque throughout the swing, rather than at impact like your experiment demonstrated. In other words, your experiment demonstrated that torque can generate significant bat speed, but you're not advocating applying it in the manner described in your experiment. Is that a fair reading of your response?
>
> If that is a fair reading, then there is an obvious question that begs asking. If bottom hand torque is not applied at contact like your experiment, then precisely where in the swing is bottom hand torque applied? If you plotted a graph of bottom hand torque versus time, where would the maximum torque occur in the swing?
>
> Thanks – JJA <<<
>
> Hi JJA
>
> You must remember that Adair stated (Nyman and BHL agree) “a force at the handle is not transferred to the point of contact.” This means they discounted torque as a factor for generating any bat speed anywhere. To them torque does not exist at initiation, not in the middle of the swing, or in bringing the bat to contact. The sole purpose of the test was to prove that forces applied at the handle IS transferred to the point of contact – torque is a factor in generating bat speed.
>
> Yes, torque should be applied through the swing. -- Applying BHT does bring the bat to contact. The reason I used the linear method of applying torque was because most readers would understand extending the top-hand (linear) better than applying torque by pulling the bottom-hand back (BHT – rotational).
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> I would venture to say that a pressure sensor pad on the handle would indicate that the forces supplied through the hands remain fairly constant throughout the swing. The more opposing the forces were the greater the bat speed developed. – Just my opinion as I have no data to support it.
>
> Jack Mankin
>

Jack,

Thank you again. I do believe I now understand exactly where you're coming from. From your two examples, torque is applied to the bat by differential forces in the hands. In the one example, the top hand was essentially pushing the bat creating torque, while in the second example, the bottom hand was essentially pulling the bat, also creating torque and thus bat speed. Combining a push-pull action with the hands unquestionably applies torque to the bat.

One important question remains. From your two examples, it appears that when torque is applied to the bat handle by the two differential forces, the wrists elongate. I cannot envision how one this can be avoided. It seems this is an inevitable consequence of applying differential forces to the bat by the hands.

From my observations, the wrist position on most swings seems relatively fixed until just before contact when the wrists do elongate. If significant torque is being applied to the bat during the swing, then based on your examples the wrists should elongate or possibly contract during the swing. Since at cursory level they do not seem to do this, this appears to be a contradiction.

Can you please explain this apparent discrepancy?

Thanks again - JJA