Posted by: Brian () on Tue Jan 11 19:36:32 2005

Hi All
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> > > > > Shawn has posted on his Discussion Board ( http://s6.invisionfree.com/Hitting/index.php ) an article by Will Carroll regarding Dr. Chris Yeager's theory of the baseball swing. Dr. Yeager’s “whip” theory sounds very similar to that expressed by Professor Robert K. Adair in his book “The Physics of Baseball.” I thought it would be interesting to discuss the fundamental differences in principles of the “Whip” theory and the “Rotational Transfer” model.
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> > > > > As I am sure most of you are aware, in the rotational transfer model I developed, torque (forces applied at two points from opposing directions) is a major factor in generating bat speed. However, for this discussion let us set aside the torque factor and concentrate on how the two different models transfer the body’s rotational energy into bat speed by applying a force at a single point on the handle.
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> > > > > Dr. Yeager concludes that hip and shoulder rotation is generated from the transfer of momentum as the front leg stops the body’s forward movement. Although I disagree with that conclusion, I do not wish to make it a point of debate at this time. Let us just acknowledge that the batter is rotating around a stationary axis and discuss how that rotation is transferred into bat speed.
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> > > > > Other than the torque factor, I think the primary conceptional difference between the “whip” and “rotational transfer” models can be shown by examining Dr.Yeager’s following statement.
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> > > > > “If forward momentum is not stopped and if body segments turn at the same time, maximal energy transfer will not result. If one were to attempt to crack a whip by rotating in a circle without stopping the hand, and therefore not transferring energy, the goal of cracking the whip would not be attained. However, if we stop the whip and then allow the whip to sequentially stop down the line, then we'll get the desired result.”
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> > > > > This is a very different concept than the principles governing the angular acceleration of the bat-head with the rotational transfer model. Bat-head acceleration in the rotational model is based on the same principle as swinging a ball around with a string. An angular displacement rate of the hand-path induces an angular displacement rate of the ball or bat-head.
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> > > > > As Dr. Yeager points out above, with his whip theory there is no transfer of energy until the hands stop. With rotational transfer there is constant inducement of bat-head acceleration from initiation to contact as long as the hand-path is undergoing angular displacement. The greater the angular displacement rate of the hand-path, the greater the bat speed induced.
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> > > > > A frame-by-frame analysis of a great hitter’s swing shows the hands do not come to a stop as required with Dr. Yeager’s whip theory. Just before contact, there is reduction in the radius of the hand-path where the bottom-hand is being pulled back around a slower moving top-hand. Some refer to it as the “hook” in the hand-path where the angular displacement rate reaches its peak. However, the hands as a unit continue a sweeping path unlike the motion used to crack a whip. – Also keep in mind that a bat can not uncoil down its length when the hands stop like a bullwhip.
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> > > > > Jack Mankin
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> > > > In reading Shawn's board, I now recall that Dr. Yeager stopped by the BatSpeed.com discussion board to make a few comments regarding the BatSpeed.com logo in the top left corner. It is certainly welcoming to have a new theory to discuss, but I find it interesting that Dr. Yeager was willing to discuss and debate a picture of a batter that we have said was created by our webmaster (who knows nothing about the swing), but Dr. Yeager had no interest in discussing the real merits of rotational mechanics (rotation around a stationary axis, CHP and torque). I would have been much more interested in hearing his thoughts on the future Hall of Famer's swing on the Swing Mechanics page, rather than the wisecracks at the artistic drawing.
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> > > > I would also be interested in hearing Dr. Yeager's response to a few questions (I'm sure that Jack has several others) to further understand, compare and contrast his beliefs:
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> > > > 1) Do you believe that a batter will generate better bat speed by a) rotating around a stationary axis during the swing, or b) shifting the axis forward during the swing?
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> > > > 2) Do you believe that good hitters initate the swing in a circular arch or do you believe that the hands are directed back to the ball in a line ("A to B," "hands to the ball")?
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> > > > 3) Do you believe that Barry Bonds applies any torque at any point in his swing? If so, at what point(s) of the swing?
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> > > > 4) Do you believe that Barry Bonds uses your whip effect? If so, which hand during Barry Bonds' swing comes to a complete stop and exactly where does it come to a complete stop?
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> > > > 5) How do you explain the fact that a bat does not flex or bend like a bat in support of your whip theory. Also, would the whip effect work if a batter was attempting to swing a 10 foot 2x4 board, or would the batter then be required to apply a circulate hand path with constant torque to accelerate the board?
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> > > > I use Barry Bonds because he is the best hitter of our time, and, of course, each question is only a starter question in that topic area.
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> > > > In any event, I wish Dr. Yeager much success with his new video.
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> > > > Brian
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> > > Your points #4 and #5 about the whip are so far off base that you're embarassing most who frequent this board. What does the stopping of the hands have to do with a whip type swing? Nothing. What does the lack of flex in a bat have to do with it. Nothing.
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> > > Once you figure out that the whip handle in a swing is the torso/body/hips, not the hands or arms, then maybe you can make an intelligent comment. <<
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> > Teacherman, like a bad habit, some things never change - one being your sarcastic attitude and the other being you dodging one set of questions while misapplying the other.
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> > First, you are attempting to defend your mentor, Nyman, but I don't think you fully understand what Yeager has written. As I understand Nyman’s theory, he does not believe that the hands come to a stop for the whip effect to occur. On the other hand, this does not appear to be what Yeager is writing.
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> > Yeager notes, “If one were to attempt to crack a whip by rotating in a circle without stopping the hand, and therefore not transferring energy, the goal of cracking the whip would not be attained. However, if we stop the whip and then allow the whip to sequentially stop down the line, then we'll get the desired result.”
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> > He continues, "A similar thing happens in a baseball swing. The body creates a forward momentum and is stopped by the front leg. The body then transfers that momentum to the hips, to the shoulders, to the arms, to the hands, and then of course to the bat. Those hitters that do this best--that actually block and transfer energy best--are your most successful hitters, like Barry Bonds and Babe Ruth. This efficient transfer is seen in those hitters who display nearly motionless bodies as the bat approaches contact. The motionless body represents maximum transfer of energy concentrated into the end of the swing, just as one does when transferring energy into a bullwhip by stopping the hand."
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> > Obviously, the stopping of momentum must start with the front leg, according to Yeager, but it cannot stop there since energy in a whip can only be created by transferring energies to smaller masses and he refers to the "motionless bodies." Yeager noted that momentum must be "blocked" for the whip to occur, meaning that the stopping of momentum must continue through the body in order to reach the "motionless bodies." Thus, I think your comments may be incorrect.
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> > Most importantly, Yeager makes an interesting point that is incorrect, which is the whole basis of his belief. With Yeager’s whip theory, the bat’s acceleration starts when the body has completely stopped or blocked momentum: "The motionless body represents maximum transfer of energy CONCENTRATED INTO THE END OF THE SWING, just as one does when transferring energy into a bullwhip by stopping the hand," (emphasis added). Importantly, what Yeager misunderstands is that Barry Bonds' bat does NOT suddenly accelerate (i.e., concentrate energy) when the body stops at full rotation, as a whip works. Instead, Bonds' constantly applies rotational forces and torque to the bat from the beginning of the swing to contact. It is an ever increasing and growing force with the rotational model.
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> > Bonds' bat has already reached maximum bat speed as the shoulders deplete rotation. Yeager’s sudden increase in bat speed caused by the "motionless body," is similar to a whip. With his theory, the shoulders must stop rotating before the energy is transferred and the bat starts to accelerate like the segments of a whip once the hand stops.
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> > You don't answer questions, but my sixth question to Yeager is the following. Since Bonds does not use forward momentum of the body during the swing (he uses a toe touch and applies only a circular momentum) and the legs, hips, torso, shoulders, arms and hands have not stopped their full rotation until after contact, how and when does the whip effect occur? When does the stopping/blocking of momentum occur under this theory?
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> > Also, Yeager suggests, "What that bat wiggling is doing is allowing him to leave the bat behind and to keep it loose like the whip." He is referring to pre-launch of Bonds and Sheffield, but my question is, since the lead arm and bat remain in a fairly fixed position to the body as it rotates, how do the arms, hands and bat act like a whip? With this fixed relationship, there is no segmental acceleration and this was the clear purpose of question 5.
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> > Brian
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> Please answer my statements. I have not defended Yeager or said anything about him. I don't have to defend him or his statements. But, you should defend yours. I know its difficult to do when you make statements that can't be substantiated.
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> I would like to know why the hands have to stop to have a whip effect. It's the handle of a whip that stops to create the whip effect. Not the whip itself. The body is the handle. It stops as the hips/torso/shoulders reach their max range of motion. It creates a whip of the arms/hands/bat.
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> Please stay on point.


Teacherman, I understand your reason as to why the hands do not have to stop for the whip to occur (you believe that the hands are part of the whip not part of the handle), but I think Yeager phrased it differently.

To answer your question, I do not believe in the whip effect in the swing for the following reasons. The body cannot act as a handle and transfer energy through the arms/hands/bat because the arms and bat do not coil and uncoil like a whip. The reason a whip is flexible is so that as energy transfers down the length of the whip and as the mass of the whip becomes smaller, the speed of the tip increases substantially. That is not what is occurring in the swing due to the rigid lead arm and rigid bat. Due to this fixed position, there can be no segmental acceleration like a whip. This is why the bat speed does not "suddenly" increase, but rather is a constant increase from initiation to contact. Try to do the whip effect with a towel, except wrap the towel around a wooden dowel and see how much whip you obtain. None, although the towel will generate speed from your hand motion, it is not from the whip effect because the dowel makes it rigid.

Lastly, the whip theory seems to suggest that if a player is late on a pitch (and momentum/handle has NOT stopped), then a batter could not generate sufficient bat speed because the whip effect has NOT YET occurred. But this obviously is not the case in the swing, as great hitters frequently are a little late and hit long home runs.

Brian