Is Exit Speed off Tee, just physics? Is Zepp Bat Speed better?

Linedrive -  I feel your pain.  I think this conversation would go a lot better if we stop trying to use theories and ideas to explain why this phenomenon ( mass having an affect ) is not happening.  

With out a Doubt, Unquestionably, Absolutely, Mass DOES have an affect on exit velocity!  Now we can spend time trying to figure out why if we need to justify it.  But for me, I would just want it to be recognized so the kids who have Elite bat speed get recognized on paper in the same way that exit velo is accepted.

What I mean by this, is;  I would guess that a recruiting coordinator or coach has to use some sort of parameters when searching a data base.  Let's say I'm searching a data base and I only look at kids with exit velo's over 90 mph.  I would miss out on smaller kids with high bat speed who have much more upside or projectability because odds are pretty high that those boys will gain mass over the next couple of years.  With their mass increase, if they maintain bat speed, I would think that some serious damage could be done with those swings.  In my original example, the 2018 with 100+ zepp readings and low to mid 80's exit velo, consistently hits with above average power.  Last college showcase, he hit the longest balls of any of the 40 or so boys there.  Many of those were the 6'3" 95 exit velo guys.  This fall he hit multiple balls over 370 ft, some over the fence, some banging the fence with force.  There are easy to find charts that show the relationship between exit velo and launch angle.  This chart will basically give you the formula to hit home runs.  However,  this issue that we have discovered will tell us that, IN FACT, there is another factor that could accompany those charts.  Bat Speed. 

So, this is what we know for sure:

 ***  Mass does affect Exit Velocity and Bat Speed can overcome lower exit velo to create power ***

I'm not saying science is wrong but we are misunderstanding the science behind this problem.  History has showed us many times that what we believe to be true, is sometimes slightly off.  And I would venture to say that this will not be the last time.

PNW,  Again, thanks for the insight and confirming what I am seeing.  I really think it was just the perfect storm with my son and I just happening to be at a point in time where our bat speed matches, and our size/strength being so very different, almost 2x in body weight and 2x in bench if you want to go there from a strength standpoint.  Junior will probably be able to boast to me that he can swing the bat a lot faster than me in about 6months, but I will still have him in exit velo for a while to come

Have you tried different size bats?  A 31" might be better for a guy his size.  I'm a little heavier and I swing a 31" in game, 33" for practice.  

HS.. Nice thought, but while he could very likely swing a 31 even faster, it would have less mass, so that would be negated.  I would say the same for a 33 inch.  He would swing it slower, but exit still be the same due to increased mass.  I think for him the 32 is a good sweet spot for him. It gives him the bat speed (Time at the plate), and also gives descent plate coverage.  No matter what exit will still be the same.

Groundout, I can say with out a doubt, If I am recruiting ball players for my program, I would take both Exit and Bat Speed into the equation.  I would of course want a high exit speed, but if that exit speed did not come along with a high bat speed, then it would not be a recruitable combination.  We want a High Exit to really drive the ball, but we also need bat speed.  I have said this multiple times, bat speed buys you time at the plate.  You will be much more likely to hit for average if you can handle the off-speed.  Slow bat speed requires you to make a decision earlier than higher bat speed.  Im sure Im beating a dead horse here, because I know everyone gets that.  If you take my current swing for example, I do not think a 76mph bat speed with 90exit is recruitable.  I just dont think my hands are fast enough.  Can I go yard?  Certainly, add on the pitcher velocity and I can, but again at the elite level, my hands just arent fast enough.  Just my opinion, but I would look for bat speed at least at 80mph, then I would look at the size of player and try to project Exit based on current size and where I see them down the road.  If they are 120lbs with a beard and 80mph bat speed, well thats probably not going to project.  If they have 80mph bat speed and already have the mass like weighing say 180lb, then we are good, because based on my calculations , they would already have the exit.  If they weigh less than 150lbs for instance, I am going to have to try and project based on height, etc. on what weight I see as being realistic that they can put on "athletically".

Groundout posted:

With out a Doubt, Unquestionably, Absolutely, Mass DOES have an affect on exit velocity!  Now we can spend time trying to figure out why if we need to justify it.  But for me, I would just want it to be recognized so the kids who have Elite bat speed get recognized on paper in the same way that exit velo is accepted.

 

Please note that I don't think anyone is saying or even suggesting that "Mass" does not have an affect on exit velocity.  The issues is . . . . which Mass or which combination and to what extent.   The batter has Weight and Mass (don't confuse the two).  Likewise, apart from the body, arms and hands also have Weight and Mass.  The bat as well as the ball has Weight and Mass.  While Weight will not change, Mass of any of these will change (increase) when they are put in motion.  Putting all these masses in motion and having them connected in variable ways at various angles . . . all, really complicates the issue to the point one can't really answer the question in some quantifiable or scientific way without knowing much more in this or any other given case.

Truman, sometimes we just cant see the forest for the trees.  At times we may not understand why things are the way they are and all we can do is look at the data.  The data will point you towards what is going on, and at some point, this will be better understood from the Physics world.

I find this link very interesting (not the exit velo for HS because it is an old link and bbcore has changed those numbers), but read on about Pujols.  There seemed to be some discrepancies with his bat speed and exit.  I find that to be very interesting knowing Pujols is a pretty good size fella.  I leave it to you to draw your own conclusions.

http://www.efastball.com/hitti...-speed-by-age-group/

PNW, what do you have for exit speed/bat speed ratios?  Lets assume a fully developed player for this.  I would like to know what you are finding for average off the tee, soft toss, BP 60-70 mph, game 90 mph.

The ratios I tend to see for maxes:

Tee -- 1.05 or less

Front Toss-1.1 or less

BP 1.2 or less

Haven't done game; done off a machine throwing 85 or so. See similar numbers as with BP.

BBCOR bats perform similar to wood re the ratio.

I say max because I think the bats have performance characteristics that when everything is perfect, there is a maximum ratio. That ratio starts dropping really quickly if things are not perfect. ie they miss the sweet spot.

Linedrive_07 posted:

PNW, Thanks for the note.  I can be pretty stubborn/persistent when needed .  I am engineer (BSEE), by trade, so am problem solving by nature.  I did not take but the required physics courses in college, so I did my best on here from a physics standpoint to explain this.  I honestly feel the smoking gun is his lead foot slipping back toward the plate through contact.  Again I really appreciate you jumping in because it seems most all are here to discredit everything just because Dr Nathan says so.  I can tell you getting up in a court of law and saying "But Dr. Nathan says" will not get you far.  

Dr Nathan is a professor on physics that has written a ton of stuff about that. you might be an engineer but I doubt you have re-invented the physics of baseball. 

wouldn't have Dr Nathan have found this out if it was that simple? 

smaller guys of course don't hit as hard, they don't put as much energy in the bat but they do nothing different at contact. 

PNW,

Do you seeing anything different on bbcore, end-loaded vs balanced?  Let's just say off the Tee?  Meaning is the ratio higher for end-loaded as I would expect?

I thought that as well. Not what we saw though. Granted comparing wood (end load) to a balanced BBCOR. Same length/weight ratio. Also, done only with high school kids.

Bat speed was lower with the end loaded wood bats compared to the balanced BBCOR bat. Average was around 3 mph lower. Ratios stayed the same.

Good to know... no reason to move away from balanced then and keep the bat speed.

I know this has been posted before but it goes along with what we are discussing. 

Stanton vs trout. 

Time to impact .11 vs .14

bat speed 91 vs 96

hand speed 32 vs 34

Exit speed (from yearly averages) Stanton was 3 mph more than trout and hit the ball a few feet further in average 

I don't have launch angle numbers  

Linedrive_07 posted:

You're asking for an explanation for why junior's BBS is lower than yours, so it would be helpful to see your swings from the same angles.

Pretty interesting Cap...  I think we will all go away from this believing what we want.  I didn't get on here to change minds.  I was just hoping to better understand what I was seeing with my and Juniors swing, and I feel while it's not completely understood, it is real.  That is good enough for me.

Atlantic, no need to go any further with this.  I appreciate the interest though.

I sent a link of this thread to Professor Nathan. He said he will answer but it will take a couple days.

If Dr Nathan wants to get to the bottom of it, my son and I would be happy to participate in a real world test in a lab wherever, so he could make all the measurements and take all the data he wants to explain the phenomenon.

Linedrive_07 posted:

Atlantic, no need to go any further with this.  I appreciate the interest though.

It's an interesting question. For the one the video you posted, the ball is contacting the bat at about 2-3" from the end of the barrel. The "location of maximum performance" for a BBCOR bat is probably 5-7" from the end of the barrel (depending on bat design and some other factors).

MidAtlanticDad posted:

Linedrive_07 posted:

Atlantic, no need to go any further with this.  I appreciate the interest though.

It's an interesting question. For the one the video you posted, the ball is contacting the bat at about 2-3" from the end of the barrel. The "location of maximum performance" for a BBCOR bat is probably 5-7" from the end of the barrel (depending on bat design and some other factors).

But he has said multiple times that the exit numbers are consistent and that no matter where he makes contact w the ball he is topping out at a number that doesnt make sense.  

Midatlanticdad has a very valid point. I thought the same thing when I looked at the video. If that ball is contacted outside of the sweetspot by an inch or so, you would see bat speed to ball exit similar to what linedrive is talking about.

And unless a kid is a robot, there can be a number of factors that affect the ball exit on individual swings. Besides the sweet spot issue, if you hit a ball with a nice launch angle of lets say 15 degrees off the tee, the ball exit will most likely be below the bat speed. Add a little downward swing plane and the ball exit ratio drops even more. That is definately physics; but, didn't see either of those with linedrive's kid swing. 

Once we figured out how big of an impact missing the sweet spot, we taped a practice bat sweet spot with red athletic tape. Made it really easy with slowmo video to see where the ball was hit.

Guys, remember the reason why I didnt want to post a video in the first place.  I knew many would try to pick apart details of exactly where the sweet spot etc is on that particular swing is to explain away the phenomenon.  I simply posted a swing to appease Gov to represent mechanics as he suggested he did not get transfer from back side, which I hope I have debunked, but I forgot the advil  From one thing that I would hope you could gather from the swing is that he is explosive and uses his body pretty athletically to get good bat speed.  Is his mechanics perfect?  No, we have plenty work to do, as there are things I see that I want to fix.

In my industry I see this a lot.  Many of us get hung up in the weeds and are not able to solve a problem because again we cant see the forest for the trees.  The key factor here that many refuse to take into account is my crap mechanics yield say 79-90mph exit (totally missing sweet spot, shanking flairing etc), while juniors top at 73mph.  I would think you would find that odd, as there is no overlap.

PNW, something else interesting to note.  I mentioned before his Summer team has Hittrax at their facility and I watch them take bp from their coach using it and we get their numbers sent out to us each week.  Guess what his max exit from bp is??  73mph (Magic number).  But again I think I know the answer.  I watch him hit some shots too on the inner half gappers and yet does not break 73mph.  Meaning ratios do not seem to be able to go up when moving from the Tee to coach throwing bp.

PNW, another question, a little off topic.  Do you see any correlation between bat speed and throwing velo?

 **I agree with you guys, definitely not his best in hitting sweet spot on that particular swing.  Based on the numerous swings in the past he has taken on the gun, I would say more than likely that is 70mph exit.    My intent was not to try to get in the cage that had the stalker set up and take numerous swings to get the Max exit and video all that.  I just wanted to give you guys a sense of mechanics.  Please dont ask for more video or things from me though, because I dont intend to put that kind of time into it.  I feel I provided enough data and with PNW, I am satisfied.  I will help Dr. Nathan if requested though going to his lab etc.

This is a great riddle to uncover, no real clear answer so far.  Same bat speed but different exit speeds (and distance). How is this possible? For me, this comes down to a couple of things:

• Are you using different bats? Length, weight, type (wood, composite, metal) model of bat, balanced vs. end loaded bat. All would influence ball exit speed.
• Swing mechanics. Some swing mechanics provide better ball exit speeds? Which swing would have faster exit speed: Ken Griffey Jr. swing with bat speed of 75 MPH or a high school freshman with bad bat drag, casting, shoulders before hips, wrist rollover early type of swing with bat speed of 75 MPH?

There is more physics to explain why similar bat speeds provide different ball exit speeds. Maybe we need to pose this question to the Sheldon on the Big Bang Theory.

I think it was a good thing that you posted the swing. It validated some questions about the quality of swing.

I do think that if anyone is still reading this and are looking for conclusions, if it's my son or daughter, off a tee, if the bat speed to ball exit speed is greater than say 1.10 (although we use 1.05), our technology had a little hiccupp.  Tons of swings will have an exit below bat speed. Some times its a sweet spot; other times it could be mechanical -- swinging down a little and cutting through the ball. Realistically, off the tee, anything with a bat to ball exit ratio above 1 we consider good.

As far as your question about throwing velo and bat speed -- now you're getting to the fun stuff. I will assume you meant bat speed to ball exit speed. This is actually where we have seen the biggest difference between physically immature and mature players. Physically mature players see bat speed to ball exit max around 1.2, if and I mean a big if, everything was perfect. Physically immature, it's less. How much? This seems to be pretty multifactorial; but, a 1 to 1 ratio would not be out of the range that we've seen, all other things being equal -- hitting the sweet spot, launch angle, etc

This has been something we have been looking at over the past couple of years cause it has affected my son. When you look at the different swings on slow mo video, when the ball collides with the bat, in certain kids (lets say physically immature kids), the ball looks like it almost stops the bat. Where precollision, there logo might be a little blurry, right after the collision, the logo becomes clear. There is definately a noticable decrease in bat speed. And the back arm doesn't continue to extend. The faster the speed of pitch or the more physically immature kid, the greater the effect seems to be. It sometimes looks like what would happen if someone hit a tree with a baseball bat. And the bat to ball exit speeds seem to correlate with it. What's the physics behind it? Who knows; just what we have seen.

The good news it that as my son (n=1) has continued to mature (at least physically), this effect is lessening, meaning he now is more closer to the 1.10 bat to ball exit off BP and pitching machine if the ball is squared up.

PNW, Im sorry I should have been more clear on my question.  As far as what you describe though with pitch velo, that is in line with what I see with my son's Hittrax data.  Coach throwing bp yet he maintains 73mph (low ratio).

Now for what I was really looking to ask.. Ha.  Do you see any correlation in bat speed and players throwing velo?  Meaning if they have a swing speed of say 80mph, does that highly suggest throwing speed (pitching velo or infield) either would have the potential of 80mph?  Maybe they are just totally un-related and can not be compared, but I am curious. 

Haven't look at that one.

I haven't looked at that either.   But is seems intuitive that there should be some level of correlation given the similar involvement of the way the core of the body is used for angular momentum.  

Truman, I am in no way going to get into Juniors throwing velo as we did with the hitting and all, but as a data point, last year at xmas when I got his zepp for him, his bat speed max was 60mph (31" bbcore).  Feb timeframe last year getting ready for HS tryouts I gunned his infield velo at 71mph.  I assume it has increased as strength and all have, but currently he is not throwing until probably early Jan. when we start getting ready for tryouts/showcases etc (my own opinion 3months is a good number for taking a throwing break, but I dont care to get into that either.. Ha.  I will have another data point in a few months (Feb).  Like you say, intuitively it seems like they would be related, but I have no idea.

Big Taco posted:

• Are you using different bats? Length, weight, type (wood, composite, metal) model of bat, balanced vs. end loaded bat. All would influence ball exit speed.
• Swing mechanics. Some swing mechanics provide better ball exit speeds? Which swing would have faster exit speed: Ken Griffey Jr. swing with bat speed of 75 MPH or a high school freshman with bad bat drag, casting, shoulders before hips, wrist rollover early type of swing with bat speed of 75 MPH?

 

- LD stated earlier that he and junior are using the same bat.

- With my limited ability to follow the physics, I think all of the existing published work on this topic suggests that holding all other things equal (same bat, same contact point and angles, same bat speed, etc) Griffey and the frosh should see the same Batted Ball Speed. Mechanics plays no role when you assume the same bat speed.

In my first post on this topic I assumed that the batter was still applying force to the ball while the bat and ball are in contact. With high speed video, it looks to me like the batter is still applying force to the bat (and ball) during the collision, so a stronger person would be applying more force than a weaker person... but the only published work that I can find says that force is too small and the contact period too brief (<1 millisecond) to be a factor. Of course I'm open to being proved correct by new research, but I'm not holding my breath.

Here's a 1999 slideshow that covers most of the basics.

http://slideplayer.com/slide/7073925/

- With my limited ability to follow the physics, I think all of the existing published work on this topic suggests that holding all other things equal (same bat, same contact point and angles, same bat speed, etc) Griffey and the frosh should see the same Batted Ball Speed. Mechanics plays no role when you assume the same bat speed.

Maybe in the lab where they can control a lot of variables. In the real world, you can manipulate some mechanics and see changes in ball exit upwards of 10% (depending on what their mechanics were before) with the same bat speed. It may make you a worse hitter; but, who cares. It's all about being "showcaseable."

Seriously though, we are in a new era. As Dr. Nathan himself said in this article  http://www.hardballtimes.com/a-tale-of-two-dingers/ "The StatCast era is upon us, and it will be very exciting to see what new things it will teach us about the game of baseball."

And with that will come a lot more questions and original ideas will get adjusted and adapted. 

Linedrive, just getting back into town here...  Thanks for being willing to post the video.  Your kid looks very athletic and it doesn't look like he has an issue getting off his backside as you thought. 

This could be a case of the light weight athletic kid with no real weight to transfer into his left side.  Athletic as heck, but he's at a constant swing speed with no real energy build up to transfer.  I'm sure once he adds a few pounds over the off season his exit velo will uptick.

It becomes another dimension of the baseball swing when you introduce separation to the young player.

Happy Thanksgiving to all of you,

David