Posted by: Cfs (jcsherwood8458@sbcglobal.net) on Sat Jan 2 08:45:23 2010

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> Hi Jack,
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> I know that Mike Epstein is a well respected instructor of "rotational" hitting mechanics with many successful students, but there is a video presentation on the homepage of his website that I believe illustrates the important differences between he and you. The video begins with A-Rod and then moves on to a college player. It describes "rotational" hitting as hitting with a stationary axis, and makes no mention of the handpath. I guess the assumption is that if the axis is stationary, the handpath will rotate or be circular. When I carefully view the video of the college player, I see several flaws or weaknesses that create a mostly linear handpath even though his axis appears stationary. From "launch" to "lag", the hitter swings his back elbow under, "slides" the bat forward, and creates little acceleration of the bat barrel early in the swing. As a result, in the "lag" position, the hitter's hands (and elbow) are too far forward. From the "lag" position to "contact", the hitter shows little shoulder rotation and extends his hands forward to generate batspeed. This is apparent in the change in his back arm angle from about 90 degrees to about 130 degrees. Also, the hitter does not rotate his front foot and his front knee locks out long before contact, forcing his hands into a linear path.
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> When I see the videos of MLB players that you highlight, it is clear that this hitter's swing is different from theirs. My basic knowledge of physics and mechanics tells me that there is no way that this hitter can generate the batspeed, especially early batspeed, that he would generate with the mechanics that you describe, as used by the MLB players. So clearly, it's not just about the axis, it's about the handpath and the body mechanics that create a CHP. <<<
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> Hi Cfs
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> I have not studied the student's swing you describe. However, those mechanics would conform to the principles Mike conveyed to me in person and in his writings. As you point out, Mike and I have very similar views regarding the lower-body mechanics that generate the body's rotation about a stationary axis. But we differ greatly on upper-body transfer principles and mechanics that converts the body's rotational momentum into bat speed.
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> When Mike and I first met at a Baseball Convention in the mid 1990s, the concept that energy for the swing was derived from the rotation of the body about a stationary axis, rather than the body's forward progression, was not accepted by most hitting authorities. Mike was genuinely surprised when I fully agreed with him. Our agreements were short lived however as it became apparent we had significant differences in how that energy was transferred into bat speed.
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> To paraphrase Mike, he basically stated (and demonstrated) that the arms should extend completely by pulling the knob of the bat to the ball with the bat barrel fully trailing. That any angular displacement of the bat barrel would result in less bat speed. At full arm extension, the wrists snap the barrel out to the ball resulting in tremendous bat speed.
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> Although in our meeting, he completely discounted my CHP principle, I have heard that in his later writings he now accepts that in high level mechanics, the hands do take a circular rather than a linear path. This may be true but as your description of his student's swing points out, a good CHP is not exhibited in his final product.
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> If I had to name the key difference in what Mike and I teach, it would be the role of the lead-arm in the swing. It is mainly the use of the lead-arm that determines whether or not the resulting hand-path is productive in generating bat speed. Below are quotes from Mike's writings that describe his view of the role of the lead-arm.
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> "Having the lead arm extended at the start of the swing makes it very difficult for a hitter - especially a young one - to stay inside the ball, and violates one of my three "core" hitting movements. Pre-extension of the arms has doomed many a promising hitter."
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> "Having "bent" elbows doesn't really have as much to do with the plane of the swing as it does being able to correctly stay inside the ball. Another reason is that you want the triceps from BOTH arms to be in position to extend through the ball at contact. If the hitter pre-extends at the launch position, he will only be in position to extend with one arm, not two, diminishing his power potential."
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> "Another reason is that you want the triceps from BOTH arms to be in position to extend through the ball at contact. If the hitter pre-extends at the launch position, he will only be in position to extend with one arm, not two, diminishing his power potential."
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> I have stressed many times that in order to produce a productive CHP, the angle of the batter's lead-elbow must remain constant from initiation through contact. Allowing a bent lead-elbow to extend approaching contact will: (1) straighten out the hand-path (2) kill the "hook" in the hand-path (3) causes both hands to apply a forward force on the handle -- no BHT.
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> Keeping the lead-elbow at a constant angle during the swing is one of the key provisions we are incorporating in the design of our Rotational Training Vest we are working on. The vest is being designed to promote the push/pull of the elbows and forearms during rotation rather than the extension of the elbows. Below are a few video clips that support this theme.
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> <a href="http://www.youtube.com/profile?user=MrBatSpeed#p/u/3/vS3HTHXspmk">4 Good Hitters - Lead-arm</a>
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> <a href="http://www.youtube.com/watch?v=98mVxe1lBKU&feature=channel_page">4 Good hitters - Back-arm</a>
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> <a href="http://www.youtube.com/profile?user=MrBatSpeed#p/u/13/4gRiRiTvbCU">Rose - The "Hook" & BHT</a>
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> <a href="http://www.youtube.com/profile?user=MrBatSpeed#p/u/2/_C2qF8d-BAI">No "Hook" or BHT</a>
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> Jack Mankin

Hi Jack,

Thank you for your detailed response highlighting the differences between Mankin & Epstein. It just so happens that the 4 video links you posted are the ones that I most focused on to try and develop my own understanding, so I would really urge others to concentrate on them and the way they collectively depict the swing.

I offer these additional thoughts on the Epstein swing. Yes, perhaps it is not the "classic" linear swing that many of us think of - with the A to B handpath, "stepping" into the ball, forward flexing of the front knee, and no stationary axis. But the forces used to create the stationary axis in the Epstein swing are still linear and not rotational. The front leg pushes back and straightens as the hitter sits on his back leg. At the same time, the arms, hands, and bat extend forward. If these two opposing and mainly linear forces occur in an "equal and opposite" fashion, (front to back, back to front) the axis will remain stationary, but neither CHP or angular displacement of the bat are created. To the naked eye this swing appears rotational because of the fixed axis and the rotation of the front shoulder as it takes up the slack in the arms. But a careful video analysis reveals its inherent flaws - bat drag and lack of early batspeed. Thanks again Jack for all of your work.

CFS