Performance of 33/23 same as 33/21?

I'm glad to have come across this thread. I think that it's a lot more than velocity that's adding power to high level hitters.

I feel that most people look at the mass of the bat as only a fixed contribution to the momentum equation (mass X velocity). I like to consider the following analogy. Take a strong swinging person through a full speed swing and just before contact, let go of the bat... Does the ball still go over the fence and the bat drive through contact, or does the bat bounce backwards with the ball dribbling through the infield. Watch the bat of a MLB player at contact and witness the ripple of the wood bending down to the hands were the handle is solidly anchored from moving by the wrists. Without the effect of the added mass from the wrist (through the body), the ball would not drive nearly as far.

In my opinion, the batters' connection to the bat is realized in the form of added mass. This is why you get some kids who appear to have great bat speed, but don't drive the ball. In most of the B and C ball that I watched, most swings are arms/shoulders driven. All of these swings are disconnected from the body. Still some girls drive the ball while others do not. I believe that dexterity is a big factor in these cases. Take the kid with high dexterity and just before impact tape her wrists and secure her rear elbow a little better. With same bat velocity I think you'll get a lot more power to the ball than without... Being connected to the bat matters.

This is what I think is so special about a strong rear hip driven swing. It's not that the bat is that much faster. It is that the effective mass of the bat is much greater when it is being moved by a solid rotating mass (body). It's totally guess, but I'd just about bet that you could double (or more) the effective mass of the bat just by having good mechanics.

The more connected you are the better. This is what upper body resistance is so important. When done correctly I believe that you pick up extra mass from many contributors.

1. Rear wrist holding the bat (adds a mass contributor from the wrists)
2. Rear wrist is perpendicular to the rear arm (adds a mass contributor from the arms)
3. Rear arm loaded against the scapula (adds a mass contributor from shoulders)
4. Scapula loaded against the back...
5. Back loaded against the hip...
6. Hip loaded against rear hip...
7. Rear hip being driven by the rear leg...

Wherever the connection is broken, you lose the subsequent mass contributors. This is why I think a knob pull kills the sequence above after #1.

All things being equal other than the bat differences, it would be the heavier bat for more power.

They were saying how pointless it was for a kid to swing a 33/23 bat when a 33/21 bat is EXACTLY the same with the same sweetspot, just lighter so the player can generate greater bat speed.

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I think too many things get pulled into this type of thread and confuse what you are asking. Really, at point of contact, it is momentum that determines how hard the ball is hit. Simply mass times velocity. So if you reduce one, you have to increase the other at the same rate in order to keep the performance of the bat/ball collision the same. What the lighter bat does is effect the performance of the batter. Ted Williams had a bit to say on that.

For MOI (swing weight) I have seen two differnt motions involving bat weight. The first is the intial swing where you are pulling the bat forward (by whatever terms we want to call this linear movement). Here you are uppulling the complete weight of the bat - MOI has nothing to do with this. The second rotational part of the swing uses MOI. So the balance of the bat becomes important.

So to the quote, yes a player might generate a faster swing with a lighter bat, but it isnt going to help the bat/ ball collision. Just allow them a split second more time to decide.

That bat speed argument doesnt hold water when you picture this... drive an optic yellow VW punch bug at 60mph straight into a full sized ford F150 traveling at 50Mph... and now measure the damage to the bug. Conduct the same test only with a ford ranger compact truck going faster at 60Mph... the small truck is going faster by 10mph, but the damage to the bug will be far greater when hit by the F150. I believe the same theory applies to bats. IMO, swing the heaviest bat you can WITHOUT LOOSING YOUR FUNDAMENTALS. If mechanics start to break down, then adjust down to a manageable drop weight to keep the mechanical fundamentals high.

drive an optic yellow VW punch bug at 60mph straight into a full sized ford F150 traveling at 50Mph... and now measure the damage to the bug. Conduct the same test only with a ford ranger compact truck going faster at 60Mph... the small truck is going faster by 10mph, but the damage to the bug will be far greater when hit by the F150.

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This isnt a valid argument due to major difference in construction, crumple zones, etc. However, the same concept of "crumple zones" applies to bats that are designed to to deform instead of all the deformation being in the ball. The idea of the trampoline effect. But the questions was of a heavier bat vs the same length lighter bat. You have to assume the same bat with the same balance and same sweet spot (if you can keep that consistant). If the swing speed is the same, the net momentum will be higher and the ball will travel further. If the weight is held the same, and the swing speed is increased, the ball will travel further. It is a balanced equation.

A side note about the car example. I saw an interesting video, I believe it can be found on you tube. They crashed to of the same model cars that were manufactured fifty years apart. The older one was certainly heavier. Measured the damage and what would have been the probably state of the driver afterwards. The findings were the driver of the newer car would have sustained some injuries though more on the minor side. Driver of the older model would have been killed. That is how the crumple zones work.

jryan15 said:

I'm glad to have come across this thread. I think that it's a lot more than velocity that's adding power to high level hitters.

I feel that most people look at the mass of the bat as only a fixed contribution to the momentum equation (mass X velocity). I like to consider the following analogy. Take a strong swinging person through a full speed swing and just before contact, let go of the bat... Does the ball still go over the fence and the bat drive through contact, or does the bat bounce backwards with the ball dribbling through the infield. Watch the bat of a MLB player at contact and witness the ripple of the wood bending down to the hands were the handle is solidly anchored from moving by the wrists. Without the effect of the added mass from the wrist (through the body), the ball would not drive nearly as far.

In my opinion, the batters' connection to the bat is realized in the form of added mass. This is why you get some kids who appear to have great bat speed, but don't drive the ball. In most of the B and C ball that I watched, most swings are arms/shoulders driven. All of these swings are disconnected from the body. Still some girls drive the ball while others do not. I believe that dexterity is a big factor in these cases. Take the kid with high dexterity and just before impact tape her wrists and secure her rear elbow a little better. With same bat velocity I think you'll get a lot more power to the ball than without... Being connected to the bat matters.

This is what I think is so special about a strong rear hip driven swing. It's not that the bat is that much faster. It is that the effective mass of the bat is much greater when it is being moved by a solid rotating mass (body). It's totally guess, but I'd just about bet that you could double (or more) the effective mass of the bat just by having good mechanics.

The more connected you are the better. This is what upper body resistance is so important. When done correctly I believe that you pick up extra mass from many contributors.

1. Rear wrist holding the bat (adds a mass contributor from the wrists)
2. Rear wrist is perpendicular to the rear arm (adds a mass contributor from the arms)
3. Rear arm loaded against the scapula (adds a mass contributor from shoulders)
4. Scapula loaded against the back...
5. Back loaded against the hip...
6. Hip loaded against rear hip...
7. Rear hip being driven by the rear leg...

Wherever the connection is broken, you lose the subsequent mass contributors. This is why I think a knob pull kills the sequence above after #1.

View attachment 4309

Click to expand...

Video | MLB.com Multimedia
For the record this was a homerun.

Nice find on the clip. The bat was still anchored in the lead hand through contact and doesn't come out fully until several frames later when the recoil occurs.

It does have me thinking though... I am curious if there was some force vector help being so far out in front. I wonder what happens with a pitch down the middle sent back up the middle.

In my experience, one of the big determining factors is how good the player's swing is. If she's primarily driving the bat with her upper body/arms instead of her lower body, a lighter bat might yield better results because she's not dragging it into and through the hitting zone.

Had a player this year who was using a RocketTech and started struggling a bit. In my view the issue was not driving the bat enough with the body - and a RocketTech is not right for her. She changed bats, but let one of my assistant coaches talk her into going -11. Her batting average did go up, but they were all weak dink and dunk hits. I don't think she drove a ball into a gap since she changed bats, and her OPS fell a lot as a result. And given her lack of speed, she really needs to be driving balls into gaps.

On paper, the lighter bat helped her. But I still believe a balanced -10 would've yielded overall better results.