Posted by: Jack Mankin (MrBatspeed@aol.com) on Thu Nov 1 10:40:09 2007

Hi All

As LRS’s and Daw’s posts indicates, there is interest in continuing the “Clips - hip & shoulder rotation” October thread. I will post it again alone with exerts from Tom’s reply.

(from October)
In a thread below (Fastpitch hitting -- Linear vs Rotational), Teacherman, Tom and I discussed our differences of how energy is transferred in the swing. Our main difference centers of the role of hip and shoulder rotation.

To further the discussion, I promised to show clips of MLB hitters and let you, the reader, decide for yourself which of our positions on the topic is verified by what the batter’s mechanics exhibits. But first, here is a brief summery of our positions.

My Position
We all agree that rotating the hips is an important factor in generating energy for the swing. However, I have always maintained that since the arms/wrists/hands/bat segmentation is linked at the shoulders rather than at the hips, the importance of hip rotation is its contribution to shoulder rotation. Therefore, it is the rotation of the shoulders (not the hips) that transferees the body’s rotational energy to the bat.

Teacherman’s Position
He contends that shoulder rotation does not transfer the energy. He believes shoulder rotation is to slow and would produce “bat drag.” Therefore, he believes shoulder rotation must be restricted and the energy of hip rotation “bypasses” the shoulders to the forearms. (How it made the jump – he never explained)

He further states:
(A) “You see....the hips rotate. The shoulders do not.”
(B) “Shoulder rotation occuring at the same time as hip rotation simply can not and does not work.

Tom’s Position
He agrees with Teacherman that shoulder rotation does not transfer the body’s energy and should be restricted. Rather than “shoulder rotation” being the source, Tom (and Teacherman) contends that it is the “tilting of the shoulders” that supplies the power.

(Teacherman’s statement)
“Shoulder rotation occuring at the same time as hip rotation simply can not and does not work.
(Tom’s reply)
>> agree, it is probably not even humanly possible to lock the two together during turning<<

The first clip is an overhead of Pete Rose. I chose this clip because an overhead view is looking down the axis of rotation and offers a better view of the hip-to-shoulder relationship.
Rose hip/shoulder comparison

The second clip is a frontal of Bonds’ hip-to-shoulder rotation.
Bonds hip/shoulder comparison

The third clip is also a frontal view of Bonds. This is a better view for discussing “shoulder rotation vs tilt.”
Bonds shoulder tilt or rotation

Jack Mankin

##
(Tom’s reply)
“Jack, thanks again for pursuing this.

I would first say that your characterization of my position is not what I have said, however, I appreciate your making the effort to summarize my position.

I did not say the shoulders did not transfer energy or momentum, I said what was important was how the shoulders functioned as part of the kinetic chain/link to control the direction and rate of stretch and unstretch of the torso which then drives unloading by momentum transfer and CHP/ball on string/pendulum type mechanics.”

Hi Tom

No, your statements did not directly say the shoulders do not ransfer the energy. However, nether would you confirm they do. I thought I could pin you down by asking, “Do you think that energy from hip rotation can be transferred to the bat without the shoulders moving (rotating or tilting)?

Your reply; “I think mechanically speaking, connection from firing of bathead once it gets out of arc of handpath to contact is via CHP/ball on string/double or multiple pendulum principles where the swing radius can not lengthen without disconnection/deceleration/loss of adequate timing.”

Tom, in all due respect, your reply appears more an effort to dance around the question than to address it. In fact, every time I posed a question regarding the importance of shoulder rotation, your replies never even mentioned their rotation – only why their rotation should be restricted.

So, once again, I will place below my position on the hip-to-shoulder rotation relationship for you to respond to, if you wish.

My Position
We all agree that rotating the hips is an important factor in generating energy for the swing. However, I have always maintained that since the arms/wrists/hands/bat segmentation is linked at the shoulders rather than at the hips, the importance of hip rotation is its contribution to shoulder rotation. Therefore, it is the rotation of the shoulders (not the hips or X-factor) that transferees the body’s rotational energy to the bat.

Jack Mankin