Posted by: daw (daw@bellevue-law.com) on Sat Sep 20 23:37:16 2008

> The baseball swing (or batspeed) isn't initiated by the hands or arms. This piece of advise is simply incorrect. The movement of the hands and arms simply gets a hitter in position to hit the baseball, it doesn't actually propel the baseball swing itself. The only reason we think it propels the baseball swing is because this positioning movement is always immediately followed by the bat flying through the zone.
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> As I've said the swing is a ballistic movement (impulse force) not a ramp movement. An impulse force is exerted by the center of the body (hips) towards the pitcher. This impulse sends a wave of energy through the body. The hips moving hips create a stretch between the hips and torso which gets the torso moving. The moving torso creates a stretch in between the torso and the shoulders which gets the shoulders moving. The moving shoulders create a stretch between the shoulders and arms which gets the arms moving. The moving arms create a LAG (not a stretch because the bat isn’t connected to the arms and the bat is a fairly inflexible object) between the bat and the arms which finally gets the bat going. This wave of energy occurs instantaneously. The bat, once it starts moving, undergoes instantaneous acceleration from a still position to its top speed. Batspeed isn’t accumulated gradually as the bat travels. Looking at past posts that discussed Gary Sheffield’s bat waggle I saw people describing his bat as having a “running start,” but this isn’t the correct interpretation of what is actually going on.
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> One question I’m sure someone will ask is “If the bat undergoes instantaneous acceleration to top speed then how come you see more homeruns to the pull side than you do to opposite field?” The answer is simple. On pitches outside a batter exerts a smaller impulse force with his hips since the bat travels a shorter distance to hit the ball, and therefore batspeed is slower when contact is made. On pitches inside the batter must exert a larger impulse force in order to get the bat to travel the larger distance, therefore batspeed is greater on pitches inside and that’s why we see more homeruns to the pull side.
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> Another question I anticipate is “Since the bat must travel a longer distance to get to inside pitches wouldn’t the deceleration it would undergo before reaching the contact point cause it to slow down making the batspeed on an inside pitch equivalent to the batspeed on an outside pitch?” Remember that the primary force that slows down the bat after the swing is the internal force of the body (not air resistance). So although the bat does travel a longer distance to get to inside pitches and does ultimately undergo a miniscule amount of deceleration due to air resistance, the internal force of the body doesn’t begin to slow the bat down on inside pitches as early as it does on outside pitches (this is obvious since the body is more open on swings aimed at inside pitches.) Therefore given the greater impulse force on inside swings and negligible air resistance, the bat will reach the contact point at a higher speed for inside swings than it does for outside swings.
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> Anyway the main point I’m trying to make in this post is that the backswing (or pulling down on the bat with the top hand does nothing when it come to creating batspeed.) The backswing itself is simply a positioning movement. The foreword batspeed created by the impulse force exerted by the hips cannot begin to be produced until the bat reaches the horizontal position (the bat can also be below horizontal but never above). And any downward batspeed created during the backswing has no effect whatsoever on forward batspeed.
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> Another issue I wanted to address in this post is the whole nonsense of “coiling and uncoiling”, cocking the hands, and anything else that falls along those lines. You can’t create explosive artificial potential energy in the body. What I mean by artificial is trying to create potential energy by simply stretching your arms back or cocking the head of the bat way back to “allow it more time to accelerate.” I’ve already covered the latter so I’ll take care of the former.
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> The stretch (or separation) that I hear so many hitting coaches talk about can’t be created until the actual swing starts. The impulse force must be exerted before that explosive stretch between the different body parts is created. So all of that coiling and cocking the hands, although it may serve in creating rhythm, is useless when it comes to batspeed.



Interesting post. What recognized scientific/anatomic principles do you cite to support it?