Posted by: Jack Mankin (MrBatspeed@aol.com) on Sat Apr 15 22:57:23 2006

>>> I am sure this is asked before but ... with this rotational mechanics what bat weight should kids use? I would imagine that it would not follow traditional suggestions. I was thinking that my son might be using to light of a bat...

Please add a search function... and if you cant drop me a line and I'll program it. <<<

Hi Wringle

I will e-mail you regarding search function s – For now, I will place below a post from the Archives on your topic.

Jack Mankin
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Re: Bat

Posted by: Jack Mankin (MrBatspeed@aol.com) on Fri Jan 7 11:58:17 2005

>>> Jack
I have always been a power hitter, using a heavy bat. I think your approach to hitting is right on. I'm now 65 playing slow pitch softball, using the same weight bat. My bat speed is not what it was 20 years ago. What is the physics behind using a heavy bat, I make my own wood bats, with slower bat speed and using a lighter bat with increase bat speed???

A second ?. I use a 36/36 some times a 36/38. what is the physics behind a long bat 36" or a short bat say 30"-32". Also I'm told that I should use a Alum. bat like other people. What is the physics behind wood - Alum???
wes
ps this is the best site that I have found on the web. Thank's <<<

Hi Wes

The basic formula for the amount of energy impacted to the baseball at contact is f=ma or f=mvv. This means that for a constant bat velocity, doubling the mass of the bat will double the impact force. However, doubling the velocity will cause the impact force to be four times greater. Therefore it appears that increasing bat velocity is more important than increasing bat weight.

This is true to a point. A batter swinging a lighter bat can generate greater bat speed, which equates to hitting the ball with more force. However, decreasing bat weights reach a point of diminishing return where lowering the bat weight does not result in a corresponding increase in bat speed. The bat feels easier to swing but the bat does not have the substance to drive the ball with any real authority.

I understand that ultra light bats allow smaller players to compete at an earlier age. My problem is the swing mechanics these young hitters develop using the ultra light bats. Professor Adair has calculated that a 35 oz. wood bat with a velocity of 75 mph can hit a ball about 400ft. He has also calculated that it takes about 3 torque horsepower to swing the bat of which the arms can only contribute about 1/3 hp. Therefore, it is the larger muscles in the legs and torso that supply most of the energy – not the arms

The bottom line is – the lighter the bat, the less the larger muscles are required in the swing. With a –11 bat, a batter can attain decent game bat speed with mechanics that rely mainly on the arms. My concern is, once a batter has developed these mechanics, what happens when the batter must use a regulation size bat (-3 or heavier) which require the efficient use of the larger muscles in the legs and torso.

Note: Wes, the walls of an aluminum bat has more of a “trampoline” effect at contact than a wood bat.

Jack Mankin