Posted by: grc () on Fri Jun 8 10:16:28 2001

In reading the Charlie Lau school of thought much is said about hitting the ball slightly downwards to create backspin. In your video you don't discuss this at all...what are your thoughts on this and is there a different technique needed to achieve backspin when swinging with rotational mechanics?
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> Hello
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> Backspin is not a desirable thing in hitting. I don't know how this one got started. Backspin slows the ball down. Some backspin is inevitable, but I don't know why people would try to stimulate it. Slowly spinning balls go the farthest. That is simple physics.
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> Golfers know this. They plan on creating a lot of backspin with iron shots near the green so the ball will stop. Every so often, they must hit on from long grass, which sucks the backspin off the ball as it comes off the club. They call these "fliers" because with little or no spin, they don't know how far they will go. Sometimes, they go 40-50 yards farther than a similar shot with no grass sucking the spin off the ball.
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> I don't know how the backspin thing got started in baseball. I suspect some pro hitting coach was looking for an image and saw the fast wrist and hand action of golfers or tennis players or some odd thing and thought it would be keep his job safer if he invented some mysterious attribute for backspin. Give them something to talk about.
> Backspin is jargon, empty calorie talk from the mystical pro gurus. It probably isn't good for you and can't be created on purpose anyway.
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> Melvin
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>"Consider first the curve ball where w = +1900 rpm. for small values of E, the distance by which the batter undercuts the ball, the ball does not slip relative to the bat and the rotation rate of the ball after the collision, called the batted-ball rotation rate, increases with E. If the coefficient of friction is 0.1, the ball surface dos not slip relative to the bat until E reaches 0.7 inch, at which point the ball leaves the bat with a spin rate of 7900 rpm at a launch angle 15 degrees above horizontal. The batted-ball speed is 120 mph, only slightly smaller than the value when E = 0, which is 124 mph. Undercutting the ball by a greater amount leads to a slipbetween the ball and bat surfaces.. However, even then, both batted-ball speed and rotation decrease only very slowly. At E =1.0 inch, the batted-ball rotation rate is 7677 rpm, the speed is 116 mph, amd the launch angle is 26.5 degrees."........................this is from page129 of chapter 5, "bat meets ball: collisions"..........chapter 5 consists of 49 pages including text, furmulas, equations, charts , graphs and one cartoon......chapter 5 is one of nine chapters in the book "Keep Your Eye On The Ball"....the book was written by Robert G Watts and A.Terry Bahill......the book was published in 1990 by W.H. Freeman Company.....ISBN 0-7167-2104-x and ISBN 0-7167-2248 (pbk)....

at the time of publication. watts was teaching in the department of mechanical engineering at tulane university and bahill was a professor
in the department of systems and industrial engineering at the university of arizona......

"Backspin is not a desirable thing in hitting. I don't know how this one got started.".........maybe it got started after the publication of the above-referenced book?.......i know there are a lot of myths out there (swing down on the ball, fence drill, etc).......but whether or not one agrees with the studies and conclusions of the authors, there was a lot of scientific analysis that went in to their conclusions that a certain amount of backspin IS DESIRABLE, and i don't think anyone can question their qualifications.................respectfully, grc...........