A guess here because I haven't seen your hitters. From what I have seen in other hitters if the bat is stopped by the impact of the ball the bat tends to 'recoil' back towards the hitter. Some hitters may be slowing down to hit the ball and stopping at contact. We all seen these types of hitters who make contact, drop the bat and run.
Hand Action at Contact
- Thread starter T.J.
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With all due respect to Ray DeMarini, I disagree very strongly with what he has written. Bat speed at the moment of contact matters a lot. Once the ball and bat are in contact, there is very little (actually, nothing) that the batter can do to influence what happens to the ball or to the barrel of the bat. The bat transfers momentum to the ball, turning it around and sending it on its way. Newton's 3rd Law, the action-reaction law, says that the ball must transfer an equal and opposite momentum to the bat. That is why the bat slows down. The more momentum the bat transfers to the ball (i.e., the faster the speed of the batted ball), the more momentum the ball transfers to the bat, and the more the bat slows down. (I am talking now about the speed of the bat just after impact. After some period, the bat probably speeds up again as the batter puts more energy into the swing.) If the opposite appears to be true, i.e., if it appears that the bat slows down more for a weakly hit ball, I suspect (as others have posted) that the batter slowed down the bat prior to impact. I certainly do not disagree with the statement that a batter should maintain bat speed up to the moment of contact. What the batter does after that doesn't matter (as the Todd Frazier HR shows), although maintaining good swing mechanics after contact is probably need to assure that what you did prior to contact was good.
FiveFrameSwing
Banned
Perhaps the logic being described here is what lead to the teaching of snap-stop swings at Louisiana Lafayette.
Based on what I saw with my own DD (8yo at the time). There might have been some deceleration prior to contact, but it wasn't easily seen watching her hit, or on video. Getting her to understand and feel that she needed to extend her power all the way through contact made an IMMEDIATE difference. My observation was that it was more about her learning how to support the force she was generating for a longer period.
FiveFrameSwing
Banned
Force = Mass x Acceleration.
Or .... Force = Mass x Velocity/Time
Or ... Force x Time = Mass x Velocity.
'Velocity' of the ball would seem to be a function of the "force" applied by the 'bat' and the 'time' that took place.
While perhaps measurably small, isn't Ray Demarini basically suggesting that one should work to maximize that time?
Or .... Force = Mass x Velocity/Time
Or ... Force x Time = Mass x Velocity.
'Velocity' of the ball would seem to be a function of the "force" applied by the 'bat' and the 'time' that took place.
While perhaps measurably small, isn't Ray Demarini basically suggesting that one should work to maximize that time?
Looking at Frazier's "no hands" HR, the barrel was being whipped to contact (as happens in a high-level swing), and there was not a lot of force being generated to the back of the handle in the time shortly before contact. Also, this is a full-grown man capable of creating significant barrel speed, with a heavy bat, hitting a light ball.
In the case of young girls, using much lighter bats, hitting much heavier balls, with less-than-optimum swing mechanics, it seems to me that the equation would be pretty different. I have seen some girls literally get the bat knocked out of their hands by pitched balls. In this case, extending swing force all the way through contact appears to my dumb head to be pretty critical....as is teaching improved swing mechanics.
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The above quote is from Ray DeMarini, as posted by FFS. This is another statement that I completely disagree with. If the bat speed at contact is the same for the two bats, then the heavier bat will hit the ball harder (i.e., higher batted ball speed). There might be other reasons why one would prefer the lighter bat (e.g., better bat control). But the statement as written, with same bat speed at contact, cannot possible be correct.
Now, assuming I am correct, in which case will the bat slow down more after impact? The answer is that the lighter bat will slow down more. The change in momentum will be smaller for the lighter bat, but momentum is product of mass*speed. When you take everything into account, you will find that the lighter bat slows down more.
Of course, I don't really know if that is what Ray was suggesting. However, once the ball and bat are in contact, there is nothing the batter can do to influence the time of the collision. It is completely determined by properties of the bat and ball. The force and time are inversely related: The smaller the time, the larger the force. But it is the force that the ball and bat exert on each other. At this stage, the batter is just a bystander.
JJsqueeze
Dad, Husband....legend
You're killing me smalls....
By the time the ball is hit, almost all that force from the human on the bat has been "converted" to velocity. Conceptually what you are posting is correct, but the relationship between acceleration and velocity is actually a rate change per time. Force in terms of velocity is F=mdv/dt. So the force on an object at a moment in time is related to how it is changing the velocity at that moment in time. It is not related to the actual velocity at any point. An object can travel at 100000000 miles an hour with no force on it, it can travel at 1 mph with no force on it.
Having too much force on the bat at impact would imply that you "left too much in the tank" and did not let the force act on the bat long enough to get it up to speed.
see this article for a nice graph of accelerometers placed on a bat....notice that the linear acceleration profiles drop into impact
http://www.lib.kobe-u.ac.jp/repository/90001381.pdf
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FiveFrameSwing
Banned
Keep in mind that Ray DeMarini was in the business of selling bats. There was a business reason to promote lighter bats.
That said, what Ray is suggesting is that the 'longer' he was able to maintain the bat/ball collision, the farther he drove the ball.
