Posted by: Fred Scerra (marlsrsoftball@attbi.com) on Sun Jul 28 17:25:27 2002

Hi All
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> It really feels good to have the board open again. --- Below is an e-mail I received while the board was down. I thought my reply might be a basis for a good discussion. I want to clarify my position as to the difference between “linear” and “rotational” mechanics.
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> >>> comments: Can you tell me the clear cut difference between the linear and rotation swings? <<<
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> When most coaches compare “linear” to “rotational” mechanics, they speak in terms of “weight-shift” vs “hip rotation” or a combination of the two, but I do not believe you can classify a batter as either “linear” or “rotational” by the differences in their lower body mechanics. Some great rotational hitters have long strides, some short, some stride with the lead-foot and hips open (separation) while others remain more closed, some transfer weight forward and hit more off the front foot (Aaron) while Bonds’ rotational axis wades away from the pitcher (negative – forward weight transfer) during his swing.
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> I think we could all agree that the great hitters develop powerful hip and shoulder rotation, they just have different approaches as to how that rotation is accomplished. However, some of the weaker hitters also weight-shift and rotate during the swing. I have seen many poor hitters who fully rotated their hips and shoulders by contact. So how can we point to any one set of lower body mechanics and claim they are “the” correct mechanics for generating a good swing.
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> No, the difference between the great and just another hitter will not be found in the mechanics that the batter uses to develop hip and shoulder rotation. The difference will be found in the efficiency of the transfer mechanics used to convert body rotation into bat speed. --- Rotational transfer principles are far more efficient in generating angular displacement (bat speed) than linear transfer principles.
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> I have pointed out many times that rotation around a fairly stationary axis supplies most of the energy for the swing, but as I have also often stated: “Nothing that takes place below the armpits has any bearing on bat speed ..... other than its contribution to shoulder rotation.” --- “Of what use is a 1000 hp engine .... if the transmission slips?” Regardless of how powerful the hip and shoulder rotation, it’s basically wasted without a well-connected circular hand-path to transfer the energy into bat speed.
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> Therefore, when classifying a hitter (Pro or Little League) as “more linear” or “more rotational,” I pay much greater attention to their transfer mechanics, than to how they developed rotation. Brett, Aaron, Bonds, Ruth, and Williams use very different lower body mechanics, but they ALL have very similar transfer mechanics. Regardless of where they hold their hands while waiting for the pitch, they ALL will launched their hands into a circular path by having their top-hand pulling back toward their shoulder as rotation is initiated. From that point to contact, their swings are on auto-pilot and the swing mechanics they exhibit are all very similar, as I said before.
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> By definition, the straighter a batter’s hand-path, the “more” linear the transfer mechanics that produced it. And, the “more” angular the hand-path, the “more” rotational the mechanics that produced it. I use the term “more” because there is no pure “straight” or “circular” hand-path, it is a matter of degrees (no pun intended). Many of the average and lower performing Pro hitters use the arms to thrust the hands away from the shoulder. That produces a more linear hand-path than the top hitters generate by pulling the hands back toward their shoulder. The lead-arm remains fairly straight across their chest and they allow rotation to propel the hands into a more circular hand-path.
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> As the swing is initiated, the more the batter’s transfer mechanics cause the first movement of the hands to be directed straighter back toward the pitcher (parallel with the flight of the ball), the less productive the hand-path can be in generating bat speed. In order to produce a more circular hand-path, the batter’s mechanics must cause the first movement of the hands to be propelled “more” parallel with the catcher’s shoulders, or perpendicular to the ball’s flight – The hands must not be thrust at, or parallel to, the flight of the incoming ball. --- So be careful of any drill or batting “cue” that would cause you to direct the first movement of your hands inside the ball.
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> "A ballistic motion, once initiated, produces trajectories that can only be efficiently changed at its margins."
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> Once the hands are initiated into a more linear path (at the pitcher -- “knob to the ball” -- parallel to a fence), there is no way the batter can later develop a productive circular hand-path. The arc in the hand-path that does occur is too little too late, and much of the body’s rotational energy will be wasted. Without the bat speed generated from an efficient circular hand-path, the batter must then rely on torque alone to accelerate the bat-head. Great bat speed requires the batter to constantly apply both torque and a circular hand path (“chp”) to the bat. Both must start at initiation and continue through the “hook” in the hand-path.
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> Jack Mankin
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I find your articles very interesting but I am not being a wise guy but could you write them in a simple way that an average guy like myself can understand it. There seems to be a wealth of information if I could understand what you saying.

Thanks