Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Sep 8 11:43:24 2006

Hi All

Since we are discussing the relationship of hip and shoulder rotation, I would like to clarify my position on the “separation” between when each starts their rotation. There is little disagreement to all that has studied the swing that hip rotation is occuring before the shoulders start their rotation. However, there is disagreement on why that separation occurs.

Many coaches maintain that the hips rotate first due to a sequential firing of the muscles up the kinetic chain. They believe that the muscles controlling hip rotation are fired first and once they attain maximum separation (or angular velocity), the torso muscles are fired. This has led to the “Sequential 1,2,3” method of teaching I discuss in the post below.

I have often stated that “separation” is not due to a sequential firing of the muscles. I maintain that during the initiation of the swing, all the muscles of the kinetic chain are fired in unison. This is not to say that the hips and shoulders rotate in unison (as a fixed unit.) Although all the muscles fire in unison, the hips rotate ahead of the shoulders due to added load the shoulders have of accelerating the bat around the swing plane.

Although I have tried to clarify this position many times, it appears there are still some who believe I advocate the hips and shoulders rotate in unison as a fixed unit. As an example, here is a post I just read on another board.

“I find Mankins post interesting because as I recall (Will have to pull his DVD out again and view) he is a proponent of rotating the front hip and shoulder together in one single connnected rotation. While his post doesnt state that it almost implies he has maybe changed his position on this relationship from his DVD?”

I will place below a post I wrote that further explains my position on this topic.

Jack Mankin
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Re: Back knee - cont.

Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Sep 1 08:00:22 2006

>>> (1) If a batter twist the back foot, they do not get more hip rotation, the actually get less and lose control of their body and thus the bat.

So the truth is that in order to rotate the way you describe, the batter must use both legs to rotate the hips and shoulders. if only one leg is used then the weight is too far back and creates a negative energy that does not transfer through the bat and into the ball.

(2) In a two dimensional video, if you watch the hands of a batter during the loading phase, the batters hands appear to move backwards. In reality, the hands rotate as the shoulders rotate in the good hitters.

(3) Most batters who bar their lead arm, can't hit inside pitches <<<

Hi Zig

You raise three points that I think the readers would benefit from our discussing them further. Each one of your points is a topic unto itself. So in order to cover them thoroughly, let us address them in one post at a time.

Note: Zig, when I referred to “spinning” in my post, I was addressing the importance of defining the axis the body rotated about – not the mechanics that induced the rotation. But that is also a subject unto itself, so let us get to your points.

Point #1
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You state, “If a batter twist the back foot, they do not get more hip rotation, the actually get less and lose control of their body and thus the bat.

So the truth is that in order to rotate the way you describe, the batter must use both legs to rotate the hips and shoulders. if only one leg is used then the weight is too far back and creates a negative energy that does not transfer through the bat and into the ball.”
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I agree. All the best hitters start with their back-knee pointing toward the plate and finish with it pointing toward the pitcher. Therefore, all these batters rotate (or spin) the back-foot during body rotation. However, for some of the reasons you outlined, I have never advocated rotating the back-knee or spinning on the back-foot to initiate rotation.

I especially have problems with “Sequential 1,2,3” method taught by many coaches. This method has the batter to; (1) stride, (2) rotate the back-knee to fully open the hips while keeping the shoulders closed to attain maximum muscle stretch, (3) contract the muscles of the abdominals and back to induce shoulder rotation.

Zig, you correctly stated, “So the truth is that in order to rotate the way you describe, the batter must use both legs to rotate the hips and shoulders.” – I agree, but in the method above, the legs are used to rotate the hip while the muscles of the abdominals and back are left relaxed – the hips are basically “freewheeling.” This means the legs have little or nothing left to contribute to shoulder rotation as the swing is initiated.

When the muscles of the abdominals and back are left relaxed as the hips rotate, there is no transfer of energy up the kinetic chain from hip rotation. For the energy from hip rotation to be transferred up, the muscles of the abdominals and back must be contacting. – Yes, I am saying that all the muscles of the kinetic chain (legs, abdominals and back) are firing in unison (rather than sequential) as the swing is initiated.

The reason hip rotation leads shoulder rotation is due to increased workload of overcoming the inertia of accelerating the bat around the swing plane – not from the sequential firing of muscles. This is most evident during initiation as the hips cock open 20 to 30 degrees ahead of shoulder rotation. However, from that point on, the angular displacement rate of the shoulders catches up and surpasses that of the hips.

Jack Mankin