Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Feb 12 12:55:42 2010

>>> Hello,

I'd like to know the cause of the shoulder rotation you discuss in the video. I agree that the shoulders open, but I strongly disagree that they pull. Also, you state that the hands do not move initially with Pujols. Do mean they do not move in relation to the body? Do you mean they are doing nothing?

Hi Bobby

Welcome to the site. -- In response to your first question, shoulder rotation is powered by the contraction of the large muscle groups of the legs, pelvic and torso regions. I definitely would not agree with a theory that maintains the action of the arms drives the shoulders open. This would disconnect the swing from those large muscles and rely on the smaller muscles of the arms to generate bat speed. -- Below is a video that discusses what powers hip and shoulder rotation.

Giambi - Momentum & the Lead-Leg

You state, "I agree that the shoulders open, but I strongly disagree that they pull." --- In a thread above (Re: Lag Position), I provide overhead video that shows the rotation of the lead-shoulder providing a pulling force (through the lead-arm) on the knob end of the bat during initiation. Then, in the "Re: Theory about how the bat is accelerated" thread, I provide two clips that show lead-shoulder rotation pulling rearward on the bat approaching contact. -- Lets us just say we agree to disagree.

You ask, "Also, you state that the hands do not move initially with Pujols. Do mean they do not move in relation to the body? Do you mean they are doing nothing?" --- Lets us once again refer to the video in the "Re: Lag Position" thread. In that video, I point out that the arms and forearms have a very important role in the swing. That role is to accelerate the bat-head around a point between the hands. It is not the role of the arms to accelerate the hands (as a unit) around the swing plane. It is the rotation of the shoulders that should rotate the arms and hands around to the contact zone.

This is what I was showing in the Pujols clip. He kept his hands back while using his hands and forearms to accelerate the bat-head rearward and waited for the rotation of his shoulders to swing his arms and hands around.

Jack Mankin