batted ball speed

EdgarFan: I wasn't referring to bat size, though that is a different variable. 

My reference was about the size and strength of the kid. I'll pick Adam Dunn as an example for this question. How much doe his size matter in relation to how far he hits the ball?

How much does Fielder's 300 lb mass help him in hitting homers?

I don't think "size and strength" of a batter matters except insofar as it impacts bat speed.  Maybe a little bit, as we learn more about the importance of linear momentum in the swing, but I would think bat speed is much, much more important.

O.K. how about size and strength in relationship to bat speed maintained after contact?

225lber versus a 160lber. Both are 6' tall, and swing the same 33" 30 oz bat at the identical batspeed and swing plane. 

I would assume the difference becomes maintaining that power through the ball which could be recorded as batspeed after contact. Most likely the bigger, stronger kid hits if farther because he doesn't lose as much power as he makes contact with the ball versus the lighter kid.

This is why I think a bigger, stronger kid with less bat speed may hit it as far or farther than a lighter kid with a faster swing. Maybe?

Believe it or not, I've read Alan Nathan (Ph.D., specialty in the physics of baseball) saying that everything that happens after the millisecond of contact has no bearing whatsoever.  I wish I could find the link - I read it on Tango's blog, but can't find it right now.  In your example of the 200+ pounder and the 160 pounder swing the same bat, same swing speed, plane, and point of contact, they should hit the ball equally as hard.  I think...that is, if I understood Nathan correctly.  As I said before, some of the video analysis of hitting, which shows the value of linear momentum, might create some effect for the bigger player, but I think it just results in more bat speed with heavier bats that their additional strength allows them to swing harder.

Seems counter-intuitive, I know.  But if you think about it, what possible force could be at work on the ball AFTER the point of impact?

I've become convinced that some people are just able to EXPLODE their energy at critical moments better than others. Examples:

- Elite pitchers are able to explode their arms and body in a special way

- Hitters are able to explode at the moment of impact

- The best linebackers are able to explode when they hit

- etc etc.

And I'm also convinced that the ability to explode has very little to do with size. Yes, size matters -- especially in football ... but some people just have something others don't.

I agree that nothing happens after the point of contact. What I'm getting at is this, bat speed measured after contact is a measurement of how much power is lost at the point of contact. 

Let's say Player A. the bigger, stronger player has a slightly lower bat speed before contact than Player B., the lighter player with more bat speed. However, after the ball is hit, the bigger player has a slightly faster bat speed after after contact.

For example, Bat speed for A. is 85mph prior to contact and 80 mph after contact. Player B. is 87 mph prior to contact, but drops to 77 after contact. The lower speed after contact is a reflection of how much power is lost at the point contact.

Then, in this example, it is possible that the bigger, stronger, player with the slower bat speed, Player A. maintained more power through the point of contact, and hit the ball harder, and farther. 

While nothing happens after contact, the bat speed measurement after the ball is hit shows how much of an impact the bat/ball collision had on each different sized player's swing.

Maybe?

jp24: You are proposing something that can't really be measured. But I see what you're saying. There have always been boxers who had one punch knockout power. But, I'm sure there were other boxers who had faster hands or delivered quicker strikes that did not knock their opponents out with just one punch. 

I think it would be interesting to see if there would be much difference between professional boxers on one of those amusement park punching machines that measure punching power. I wonder if the one punch guys would have a higher output than the quick hands guys. 

Dr Nathan

for a typical ball-bat collision in the barrel of the bat, the batter's grip plays absolutely no role in determining the ultimate fate of the ball.

In fact, the batter could just as well let go of the bat just prior to meeting the ball and it would make no difference to the ball

@ Stafford, regarding bat speed after contact being a measure of power/momentum maintained (or at least not lost):

Again, I realize that is all seems counter-intuitive, but the point of contact is such a minute point of time that I don't think it matters.

I found ONE of the links I was looking for, and it kind of addresses this:

http://www.insidethebook.com/e...at_ball_collision/#2

You almost have to read through all the surrounding comments to get the full meaning, but he talks about how a batter wouldn't even need to have his hands ON the bat for it to make a difference.  He also talks about something that I think is analogous to what you're saying, in an experiment where they measured ball exit speed when a ball strikes a bat that is suspended in air but not rigidly fixed and another where the bat IS rigidly fixed:

He answered this question:

"Let’s say that you had a ball traveling at 80 mph approaching a bat.  One bat was held stationary at the handle.  Another bat was dangling in the air by a string.  The ball hits both bats.  Will the ball go further coming off the rigid stationary bat?  That would seem intuitive."

In this way:

"The experiment you describe has actually been done.  Namely, a ball is shot out of a high speed cannon onto a stationary bat.  In one case, the bat is held rigidly at the handle.  In another case, the bat is suspended with strings, essentially free.  In yet another case, the bat is pivoted at the handle.  The speed of the ball coming off the bat is exactly the same in all three cases (assuming the impact occurs in the barrel)."

He he also said this, which touches on some of what we've been talking about:

"I agree that muscle mass, even upper body muscle mass, can affect power.  But it does so by increasing the speed of the bat prior to its collision with the ball.  As I said in my previous post, the batter could just as well let go of the bat just before contact with the ball and it would not make any difference in what happens to the ball.  Strange, perhaps (although not to me), but true nevertheless."

Thanks SoS, searching as you were posting....  You found the same one I did....

O.K. you beat me to the punch on the muscle mass portion of where I was going next. And I love controlled experiments. However, I also believe in anecdotal evidence.

I wonder if anyone measured Bond's bat speed at say, age 23 and again at say, age 38. Did his bat speed really increase so much that he went from one of the best players in the game to something superhuman. Or McGuire, Sosa, and especially Quinn. 

There is obviously something to the size and strength portion of this discussion. Is it just bat speed?

"There is obviously something to the size and strength portion of this discussion. Is it just bat speed?"

Yes, the bat is part of a system in motion that includes the body.  The bat is not flying through the air on its own.  The ability of the hands, arms and body to resist the opposing force of the ball is a factor in how effectively the momentum of the bat is transferred to the ball.  Bigger, stronger bodies usually are better equipped to do this.  But since momentum is a function of both mass and velocity, higher bat speed can make up for smaller bodies or less hand/arm strength.  There are lots of examples that come to mind - Willie Mays and Ken Griffey were not large men but hit the ball a long way.  Likewise, a big person with low bat speed will not hit the ball a long way.  But bat speed being equal amongst two hitters, the larger stronger person will hit the ball further.

What weighs more? A ton of feathers, or a ton of bricks?

It doesn't matter what's holding the bat, it's just bat speed.

http://baseball.physics.illinois.edu/grip.html

It's just the speed of the bat (and the ball). You can throw the bat at the ball you'll get the same results as long as the bat speed at the time of collision (and angle of the collision I suppose) are the same.

Not true unless you defy the laws of physics.  Mass and velocity both factor into energy.

With respect to the size/strength of the player in the actual collision math, http://www.acs.psu.edu/drussell/bats/batw8.html "the force on the bat by the player is very much smaller than the forces between bat and ball during the collision"

Bat size wasn't mentioned in the original post I quoted.  For a given bat (which appeared to be assumed in that post), bat speed is all that matters.  Mark McGwire or Rey Ordonez, if they're using the same bat and make contact with the ball at the same speed and angle, they'l get the same result.

Where strength comes in to play in real life, of course, is that Mark McGwire and Rey Ordonez will get very different bat speeds using the same bat.

That works for me   Thanks for pulling up that link, very interesting.

Originally Posted by pitchout31:

Isnt the correct metric that matters - exit speed? …

It could be, but the only true measurement is taking every swing in a game, and getting the average.

What a debate!  More than I could have ever asked for.  Thanks everyone! 

First, to illustrate Professor Nathan's point about the hands not needing to be on the ball, I offer video of a Todd Frazier home run:

http://wapc.mlb.com/play/?cont...1821083&c_id=mlb

Second, w/r/t this:

Yes, to the last part of your last sentence.  That video shows something Professor Nathan was saying: the batter, with all his strength, talent, etc., is just a mechanism for getting the bat to the right place at the right time.  Assuming the same bat gets to the same place at the same speed, plane, and contact point, it doesn't matter if it was swung by a 120-pound teenager or a 225-pound major leaguer, or even (counter-intuitively) by somebody whose hands aren't even any longer ON the bat!

The thing is, as I said (much) earlier in this thread, the chances of "all else being equal" in these things is so remote as to border on impossible.  Stronger people are capable of swinging heavier bats with more bat speed.  This matters.  The talent and mechanics it takes to make the kind of perfect contact these theoretical discussions presume is, as we all know, incredibly difficult to achieve, and matters most of all!  And as SoS pointed out (much) earlier in the thread - and I see has just reiterated - distance (something that certainly correlates to performance) depends not just on exit speeds, but launch angles, and spin rates, etc.

This is yet another reason why TrackMan data is going to be so valuable. We got distance info at the MLB level from HITf/x data, and could infer things like exit speeds, but TrackMan measures this (and spin rates) directly.  If you're a baseball science geek enough to still be participating in this discussion, you gotta love where having that kind of observational data can take this discussion!  And how it translates into performance, with correlations to higher batting averages, and slugging percentages.

Great discussion. Thank you all.

That's good velocity coming off the bat.  The important measurement is during a game against a quality pitcher.  That's what will garner interest.