Going Yard: The Science Behind Bats and Balls

“Torpedo” bats. Drag. Lift. Learn more about exciting new developments and the science and standards at play in baseball and softball on the latest episode of Standards Impact. 

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Dave Walsh (00:12):

Well, it's spring in case you haven't noticed. And for many around the world, that means baseball and softball season. We all know the smell of freshly cut grass, the crack of the bat, the electricity of a close game in the last inning. Those are the moments that make baseball and softball so special. Whether you're at a local field or a professional stadium. Few things evoke nostalgia like the Game America calls, its national pastime. But baseball is far from a regional pastime. Hugely popular leagues in Japan, the Caribbean, Taiwan, and more have made baseball a truly global game as the new season kicks off here in the us, MLB teams are gearing up and youth leagues are starting up around the country on this episode of standards impact. Learn about the standards that support safety and performance in baseball and softball. I'm your host, Dave Walsh, and today we're joined by two experts in the field of baseball standards. Lloyd Smith, deputy Director School of Mechanical and Materials Engineering at Washington State University. And Nick Smith, lab manager with the Sports Science Laboratory at Washington State. Both have worked with MLB and other organizations on standards for baseball and softball for some time now.

(01:14):

So we'll get to the interview with Lloyd and Nick in a minute. But an interesting development happened in Major League Baseball recently over this past weekend. So we scheduled a quick call to discuss this breaking news with Nick and Lloyd sent along a statement, which I'll read in a moment that sounds ominous, but for anyone who follows baseball, uh, they've most likely seen a news item recently about the so-called torpedo or bowling pin bats used by the New York Yankees in their opening series. These bats had an odd shape never seen before, and many credited the bats for the Yankees offensive explosion, which tied a record for the most home runs in a three game series with 15. So with that brief background and the full disclosure that I'm a Yankee fan, so I didn't mind this offensive explosion, Nick is with us, Nick Smith. And what can you tell us about the shape and design of this new bat and how it might've affected the hitters and how they make contact? What are your thoughts on it?

Nick Smith (02:06):

Yeah, so all I've seen are pictures taken from a broadcast. So it's not a lot of detail about the bat, but, but physically it looks like they've put more material closer to the knob end and removed some material from the end cap end and that gives it that torpedo or or bowling pin shape. And what that does well in terms of standards since of things we talk about that will, um, I don't remember the number of the standard, but we have a standard for mass moment of inertia, which is a fancy way for saying the swing weight that should lower the swing weight. So it'll move the balance point closer to the batter's hands. It'll make the bat feel lighter, even if it has the same mass when they're swinging it. And that'll have two effects. One, it'll let them swing the bat faster, but it'll give the bat less inertia in the bat ball collision.

(03:02):

So if that was the only effect, I would've expected the Yankees to have a higher batting average but not hit as many home runs. And you can get a similar effect, just, just the inertia. Some bats will have, you know, a solid end cap and others will have that cupped. The cupping is removing material and lowering the swing weight in a similar fashion to removing material like that torpedo shape. So that might have a similar effect. So in, in terms of standards, that's one thing I would expect to be different, but what I've heard baters talk about is having more material closer to the inside might help them foul off a pitch that they otherwise might have missed. You know, if they're hitting the ball farther toward the inside, they have more material to make contact with the bat and that that could very well be true. But I don't really have a test standard to talk about that.

Dave Walsh (03:52):

Yeah. Well, it's interesting you said that because I have Lloyd's email here and he concurs, and I don't think the two of you collaborated on this. He says that the, the power explosion was almost certainly a coincidence. He says the primary benefit of the new shaped bats is primarily to turn close strikes into foul balls, give the batter more life at the end of the count, what you just implied, a larger barrel at the hitting area would provide a little flatter surface, which might lead to slightly better control over the launch angle. But essentially he's agreeing with you that the home runs were a coincidence. Maybe it would contribute to better hitting in general, but not exactly a home run explosion like we just saw. I guess my big question is, and most of the sports fans I talk to about this who are not scientists, why didn't anyone think of it sooner if it's, if it's giving an advantage or is the fact of the matter that it's not giving a great advantage? So it, that's why it hasn't been tried before.

Nick Smith (04:45):

Well, and that, that's a good question. One article I read, uh, another player from a different team said, oh yeah, I've done something similar before. So maybe something like this has already been done. But, uh, certainly I'd never seen it before. And certainly people are more open to, you know, analytics and trying new things in baseball these days. Uh, but the sport's been around a long time. I was looking at some wood bats that we have around our lab, and most of them have a gradual slope that's just always getting thicker. Towards the end of the bat, most of our bats were that design. We had a few with a longer barrel that was straight, and we're gonna try and make our own torpedo bats with those to, to test and see if anything's different. But to me, I think the biggest reason why not is there's a possibility that they've moved the sweet spot farther to the inside with this design.

(05:36):

And that's actually not optimal. If you were trying to hit the ball the farthest, you'd wanna do the opposite. You'd wanna move the sweet spot towards the end of the bat instead because your velocity, well, the relative velocity is gonna be proportional to how far outside the bat you are. So you would want the sweet spot of your bat to be as close to the end as you can, and you'd wanna hit the ball there so that you could hit it the fastest and farthest. So moving your sweet spot inside and contacting the bat inside will give you a lower exit velocity, so potentially less home runs. So potentially the focus in the past has been training batters to hit that way, and maybe people have decided that that's not worth the effort and it's better to just give them a bat that'll hit the ball where they're swinging right now, instead of training their swings to make a hit farther outside.

Dave Walsh (06:32):

Well, either way, it sounds like it's much more complicated than a lot of, uh, sports writers and sports highlight shows have made it sound that they, they shape the bat like a torpedo and that's the reason for the home runs. But we're going to find out, I guess in the coming weeks what happens with their offense. I mean, if they continue to hit 15 home runs every series, I suppose people will have to take a second look, but from what you're saying, the science is pretty clear.

Nick Smith (06:55):

Yeah, yeah. We, we wouldn't expect it, but to have a major difference. But we are testing it, so we'll, we'll see. We had some bats with a straight barrel that we tested yesterday, and hopefully today our machine shop will have turned those same wooden bats so that we're not getting wood variation into, uh, torpedo or bowling pin shape. And then we'll, we'll test 'em again and see what the difference is. So that, that should be fun. But we, we expect it to be the same. And one thing that, uh, we were, we were all talking about this in the lab too, not everyone on the Yankees is using these new bats, right? Uh, Aaron Judge notably sounds like he doesn't like them and sticking with his normal,

Dave Walsh (07:33):

That's an important point to note.

Nick Smith (07:34):

Yeah. And uh, from what I, I am not a Yankees fan and didn't watch those games, but from what I understand, a significant percentage of those home runs did come from Aaron Judge. So anyway, there's, I, I think some of it is certainly the Yankees just have a lot of good hitters and combined to have some good offense this weekend.

Dave Walsh (07:54):

Yeah, well our, our listeners in Boston won't want to hear that <laugh>, but they will wanna hear that this offensive explosion, scientifically speaking, should die down and get back to the normal average of home runs. So anyway, we thank you for being with us for this breaking news segment and right now we'll return our listeners to the regularly scheduled podcast. Lloyd and Nick, thank you for being with us today. We really appreciate it.

Lloyd Smith (08:18):

Yeah, thanks for having us. You're welcome. Glad to join you.

Dave Walsh (08:22):

Alright, well, since we're talking about baseball, as we all know, the big topic, whether you're a fan in Japan or Latin America, Taiwan, all over the world is the home run. It's one of the most exciting events in sports. It's up there with a touchdown in football, a goal in hockey, you name it. And baseball fans in particular are always obsessed with this number. And last year saw an unusually low number of home runs here in the United States and Major League Baseball, at least compared to a few years ago when there was a record set. So what can the two of you tell us about standards for baseballs and baseball bats and the ways they impact the game? Probably most fans don't realize just how much of an impact they have. So what can you tell us about that? And Lloyd, we can start with you.

Lloyd Smith (09:01):

Well, the first two things you described are directly related to the work that we've been doing. So it's exciting and interesting to see that the things we're doing and involved in have result in play. When you talk about major league baseball, there has been an issue with the seam height and the amount of drag the ball has. The drag of the ball has been really surprisingly consistent for over 60 years. So it was surprising when we saw a change in, in offense that was significant and not attributed to performance enhancing drugs. And we were able to show that the ball had changed, that the seam height had become a little flatter. And it was amazing that a seam height difference of about 6000th of an inch increased the home run production by about 25%. So there was a really significant sensitivity to a a small parameter. We now have a standard to measure seam height, so we can control that directly. What we still don't have a standard for is measuring the lift and drag of a baseball, which is ultimately the parameter we want to control. So there's perhaps more work that could be done there.

Dave Walsh (10:15):

Yeah. And what about you, Nick? What would you say?

Nick Smith (10:17):

Well, it's ironic that we're talking about major League baseball. We are, you know, involved in a subcommittee that deals with a lot of test standards for baseball, very few of which have any effect on major league baseball. So major League baseball, they use only wood bats. Many other leagues allow non-wood materials in their bats, but they want the performance to be similar to wood. And so we have test standards that measure the trampoline effect in a baseball bat. And so many of these other leagues, they're trying to have bat performance similar to wood. So the the barrels are not too, too springy, getting maybe too many home runs. So that's one test standard that could affect a home run rate. It doesn't in major league ball because they have always been using wood and they don't use any performance test on their bats. There's also ball tests that can be done. We have a test standard that measures the dynamic stiffness of a ball. There's also a static compression on the ball or a coefficient restitution on the ball. So those are all different ways of measuring the bounciness or hardness of a ball. And once again, that's not directly regulated in major league baseball, but other federations, often softball will have limits on that to make sure the synthetic materials they're using aren't artificially changing their game in some way.

Dave Walsh (11:38):

Well, that's a good segue because full disclosure, a few years ago I interviewed Lloyd for an article in standardization news. And the topic did largely revolve around youth baseball and a bit revolved around the, uh, NCAA game. And at that time a few years ago, there was controversy for those of us who were little league parents like myself. They had just changed all of the bats in little League to go from these, well, I'll just call them as a lay person, a home run friendly bat to a bat that seemed debtor to me. And actually there were numbers that supported it between 2013 and 17, the Little League World Series averaged 65 home runs per tournament last year. And this is, you know, one of several years with the different bats they had 15. So that's a pretty big difference. And either one of you can take this question, but what can you tell us about these? I'm saying quote unquote new standards for youth bats or the new parameters that were put on them.

Lloyd Smith (12:28):

I'll start off on this one. This I guess could be described by the, the terms people using software, what some people call a bug, other people will call a feature. You described the decrease in home runs as being a controversy. That was actually a very carefully designed and engineered process. So prior to 2018, little League was managing the, uh, bat performance of, of all youth baseball. And they were using a test method that was around 20 years old and it had a number of known deficiencies. So the methodology was not ideal, number one. Number two, there was a question about what level of play, what level of bat performance was healthy for the game, what balance do we want between offense and defense? And the decision was made that the bats needed to be more wood like. So the performance needed to come down. Some people relate that to safety, but that really wasn't the motivation.

(13:23):

It was just about where do you want the game to be and, and how much offense and defense do we want to have in play? So that was carefully considered and that was an aim of changing the standards. So to have a more rigorous standard, number one. And then number two, have the performance level be more wood like. So that's what we did. And that applied to all youth baseball across the country. All youth baseball federations use that standard. And as a consequence, home rates, uh, came down. So that for us would not be a controversy, but something that was intended and worked very well. We, we consider that to be a very successful change to the standard given the the aim that was put forward.

Dave Walsh (14:01):

Yeah, and I should have qualified my question and mentioned that I was the father of two youth baseball players at that time. So to them it was a controversy. So they wanted to hit about 300 home runs per tournament. But yeah, uh, to your point, it was about the competitive balance of the game. Nick, what were your thoughts on that though? And I know, you know, this does revolve around that coefficient of restitution. And I, and I recall that it was kind of as a lay person, a non-scientist, it was a little counterintuitive to me that the more of a trampoline effect that the bat had, the farther the balls went. And, and in my mind I just always thought the harder the bat the better. But you can clarify that, I'm sure.

Nick Smith (14:35):

Yeah. And this actually, I guess Lloyd knows more of the history of this, but people discovered this kind of by accident when wood bats were breaking and people were looking at other materials to make bats out of they, they turned to metal bats and just to get the weight right, you had to make it hollow. And they discovered that by making thinner walls, they had a higher trampoline effect and would hit the ball farther. And so that's essentially what we measure and what we've set up in our test standard. We have a bat and we have a, you know, a cannon, a pitching machine that shoots the ball off of the bat and we measure the speed before it hits the bat and the speed after it hits the bat off that rebound. And uh, with, with our test standards, we're able to determine what we call the BB core, the batted ball, coefficient restitution or the trampoline effect in the bat. And theoretically people could set any limit on that. But the federations we've worked with have made that kind of a wood like limit.

Lloyd Smith (15:30):

Lemme speak to that trampoline effect because it's, it's super interesting and especially that it was discovered by accident. But when a ball impacts a bat, about 75% of the energy is lost. There's a tremendous amount of energy that's lost in the impact and most of that energy is lost from the ball. The bat itself is actually pretty elastic. So when we talk about this trampoline effect, what we're talking about is doing something that doesn't lose as much energy as you would otherwise. And that's where the softness of the bat comes into play. If you imagine two extremes, one bat that's super hard and one bat that's super soft, the hard bat is going to deform the ball more. And when the ball deforms more, it loses more energy. Where if you're impacting a soft bat, the ball deforms less, more energy is stored in the bat, which returns that. And so you end up with overall less energy being lost. So that's super important in baseball, but it's important in really any sport that involves impact. All of this directly relates to golf. The exact same mechanisms are happening in golf and they have the same kinds of things going on with with new golf club designs.

Dave Walsh (16:37):

So that just takes me again, as a lay person off on a different tangent just for a second. There must be a point at which the trampoline effect becomes self-defeating. I would imagine like if you tried to hit a baseball with a noodle, it's not gonna go anywhere. So there must be a softness point at which it just doesn't have a trampoline effect anymore. Is that accurate to say?

Lloyd Smith (16:55):

Yes, and it's a really fun thing to explore academically we look at that, but that comes down to how stiff the bat is. So if you try to make the trampoline effect massively large, two things can happen. One is the materials become so thin that it's difficult to even design an object that would, would be effective. And then the other would be as, as you say, that it's so flexible that it's not able to impart any real impact into the, into the ball. But for the materials that we use that that one associates with play and that that have any resemblance to a a wood bat, those effects don't come into play.

Dave Walsh (17:33):

And Nick, for the science geeks out there, what is the limit currently on a youth bat for the coefficient of restitution? What are the numbers within that range? Like what would make it even more dead and what would make it really powerful in hitting a ball at least?

Nick Smith (17:47):

Yeah, so the numbers for the the BB core standards we use, we have two different standards. The youth standard, which is called USA BAT and the NCAA standard, which is called BB Core. And they have different numbers and there's different correction factors that go into those numbers. But it works out to be about 0.5, about a half. So if you were dropping a bouncy ball and had a ruler, that would be a way of measuring the coefficient restitution of a bouncy ball. Point five would be it coming halfway back up.

Dave Walsh (18:16):

Well that also brings us to another area of what my high school baseball player would call a controversy. It's probably not to the regulating bodies. And that was seam height that you mentioned earlier. Lloyd, you know, these standards don't so much relate to MLB, but that's when these topics reach the public eye because they're reported on. And you mentioned that change in seam height, that was minuscule. Now my son will tell you that the lowered seam height makes it harder for him to throw a curve ball, but that's really not what the standard was addressing. You know, when a ball is smooth, you can't dig your nails into it and you can't get your fingers on the ridges there to spin it the way you want to. But just in general, what can you tell us about the specific standards for baseballs and what they regulate and how they regulate it for that seam height?

Lloyd Smith (18:54):

So there's one standard currently that we use to measure seam height and we measure seam height at a number of locations around the ball. And we're comparing the maximum height of the seam to the height of the ball just adjacent to the seam. So that provides a standardized way to let us know where that's at. And as as you noted, the seam height is designed in balls for the major league baseball, it's sewn and then after it's sewn, it's actually rolled. So they try to get that that seam as flat as they possibly can used to be in college baseball, that there was a raised seam and that was done as you noted, to help the pitcher get more spin on the ball. But there was a price for that too. Then the ball didn't carry as far a few years ago, there was a decision made to have the seam height for college play also be flat.

(19:45):

It's not as flat as you would have in major league baseball, but it certainly wasn't, it's not as raised and pronounced as it was then. If you go to softball in slow pitch softball, the seams are very flat scaling it, it would be very comparable to the major league baseball. But in fast pitch softball, the seams are intentionally raised significantly. That's a very high seam they have in fast pitch softball. So there again, you've got a ball that's going to be easier to get spin on and then that ball's gonna have less carry is compared to, to balls that are are flatter. So this the standard we have with seam height that really now is the first time we're quantifying that for decades since the game existed, people just called the balls flat seamed and Ray seam. There was, there was really no way to quantify that. And, and what is a ray seam and a flat seam? And manufacturers would get confused because some manufacturers would call a product a flat seam and someone else would look at that and say, no, it's a ray seam. So that then allowed us to say what actually is and constitutes a flat seam ball.

Dave Walsh (20:44):

And Nick, what are your thoughts? What would you add to that? Anything?

Nick Smith (20:47):

Well, just speaking to maybe your son, we talk a lot about the drag on the ball. That's how far it would carry after it's been hit. But the lift on the ball also matters how much lift it has will correspond to how much movement he can get on his pitches. And different balls that have a different amount of lift based on their seam height can have different movement for the same spin rate, the same pitch will move differently.

Dave Walsh (21:13):

So what do you mean when you say lift? How would you define that? Because I'm thinking of a baseball being batted and heading toward the fence with a high lift. Is that what you mean?

Nick Smith (21:20):

Well, I'm talking about it being pitched with lift, but you're, you're right. So the lift and drag will apply to the ball.

Dave Walsh (21:26):

'cause they always want the ball down in baseball, they, the pitchers want it down. So lift is counterintuitive

Nick Smith (21:31):

<laugh>, right? So aerodynamic lift, it's a property that applies both when it's being pitched and after when it's been hit and the the aerodynamic drag as well. So you'll hear people talk about that with wings as well. It's the same stuff. But what's interesting with baseball is you can control what direction the lift is acting in by what direction your spin is acting. So if you're throwing a curve ball that's supposed to drop down, you're using the property that gives lift to the ball, but it's actually going backwards. It's going down based on what direction you put your spin. Or if you're doing a slider and you're trying to, or a sweeper and you're trying to curve the ball to the side with your spin direction, you're changing the direction that that lift is acting. It's not always going up. It's a aerodynamic force. So yeah, lift isn't quite as important as drag on how far the ball carries low drag when it's hit means it'll carry farther high lift when it's hit. Might make it carry a little bit farther, but it, the drag's more important in that aspect. But when you're pitching drag would, would slow down your pitch a little bit. So you might notice that. But you, you notice the lift in how much the ball moves and you can control that direction with your spin.

Dave Walsh (22:44):

That's really interesting to me. 'cause I, I did not know that. And I'll tell him the next time that he needs more lift on the sinker <laugh>, just confuse him. <laugh>,

Lloyd Smith (22:52):

The same thing happens in golf. When you're golfing and it slices or hooks, that's because you haven't hit the ball squarely and you don't have the ball spinning with the spin axis horizontal, it's got a slight tilt to it. And that's what causes those movements.

Dave Walsh (23:04):

Yeah. Well now that relates directly to me because I slice and hook almost every drive that I take. So that's also good to know. But one further point with seam height is that, you know, you've both mentioned drag and I recall, uh, when researching the article that I mentioned earlier and just reading articles in general that, and I could be wrong, so correct me if I'm wrong, when you lower the drag on a ball with lower seam height, it adds, you know, 10, 20, 30 feet to the trajectory of a ball that's been batted. It's a, it's more of a factor than people would guess is what I'm trying to say.

Lloyd Smith (23:33):

It's really surprising how important drag is. And when we were looking at the seam height issue with Major League baseball, that really came forward when you're pitching the ball, movement's important. So the sea height and lift that lift force is really important, but when you're hitting the ball, it's really all about drag lift is important, but drag is much more important. And it's, it's this home run. There are so many balls that are hit right toward the fence. So a little bit of change in drag makes a huge difference. You're either the hero or you're the guy that lost the game, that hit the easy fly ball to catch. So it's an interesting part of, of our sport where a very small change has an important impact on the game. And what's also interesting here with the sea height is we have all this technology, all these things have been done on bats to make them high performing, feel good, look good, and have lightweight, all of these neat things.

(24:26):

The ball is largely unchanged. We're still winding wool, which is a natural material that's taken from sheep and it's wound around a rubber pill. That process is automated, it's still covered with some type of leather. Very often it's natural leather, but it can also be synthetic leather. But then it's sewn by hand. The the seams you see on a ball, every one is sewn by hand. So it's a ball made from natural materials and largely handmade. So when I go to these places where I see the ball made, I come away asking myself not why does the drag change so much, but why doesn't the drag change more? How, how can you have all of these natural and manual processes and end up with a product that is actually as repeatable as it is?

Dave Walsh (25:18):

Yeah, and as you say, the machinery is calibrated precisely, I'm sure. And the hand sewing goes exactly the same every time, but there's no actual standard that governs the entire process. Is that correct?

Lloyd Smith (25:28):

That's right. They govern the finished properties of the ball. So the ball weight is tightly controlled, the ball size is tightly controlled. We now have the ability to control seam height, but still there's a lot of nuance in how a ball is seam. They even talk about left-handed and right-handed stitches, and how tight is the person pulling on, on the string. We were just talking to a bat manufacturer the other day and he noted that you can't have a machine sew these because when they pull tension on the strings that are used to make the seam, that's done according to the leather that they have on the ball and on some balls, some types of leather, they'll pull harder and other types, they won't pull this hard. And that's something that apparently, uh, a human is required to be able to get that tension. Right.

Dave Walsh (26:13):

That's maybe the most interesting revelation from this whole podcast because I didn't realize that, you know, you don't even think when you hear hand sewn, you don't actually think about the person sitting there doing it. It's just, so as you say, it's probably a miracle, not a miracle. It's probably very surprising that things don't turn out less regulated.

Lloyd Smith (26:29):

I've been to one facility where they sew balls, this is for the major league ball, and there they had about 200 people in a room all pulling these seams. And for me it was just mesmerizing to watch these people working and how hard they worked. One person's days work is sewing about two dozen balls, but that's a small portion. The big production is in China. I just can't imagine in Asia what these facilities must look like for the, the number of balls that are produced.

Dave Walsh (26:58):

Yeah, I mean, two dozen is like one game in MLB. That's if that,

Nick Smith (27:02):

I I was gonna say it probably a lot more than two dozen balls used in one game. <laugh>

Dave Walsh (27:06):

<laugh>, yeah. What, what were your thoughts on the whole subject of seam height there, Nick?

Nick Smith (27:11):

Oh, I, I don't know that I have any more besides what we've said. Um,

Dave Walsh (27:15):

Have you witnessed the process like, like Lloyd

Nick Smith (27:18):

Has? I've never seen it, but as we were talking yesterday, what was interesting to me that was said when you're, these people are adjusting their tension, they're trying to get the ball to look right, right? If they just kept the same tension everywhere on the ball, it might wrinkle or something, right? 'cause you've got this leather that's got different tension at different places. And so it's not just that, you know, with ball A and ball B, they're using a different tension. They're constantly adjusting their tension in one ball to get a perfectly smooth ball to avoid any wrinkling as they're sewing that together. So it's kind of cool to think about the, the skill that goes into making these dozens of balls that we just throw into the stands if they hit the dirt at the game.

Dave Walsh (27:59):

So we've been discussing the standards for the game of baseball that affect performance, that affect play, but this is an A STM podcast. So we'd like to talk about the committee that you both belong to, which is FO eight. And that's the sports equipment playing surfaces and facilities committee and the work that you do. And one of the main standards there. And there are many, but one of the main ones that baseball parents will know is F 2219, whether they realize it or not, because that is the test method for measuring softball and baseball bat performance factor. And that's the BB core, which is etched on every youth bat that is used. So how was this bat performance standard developed and what were some of the misconceptions that needed to be overcome to get there?

Lloyd Smith (28:39):

Well, this is a really interesting process and something that has surprisingly taken over my career. I've never really planned it to do so, but for some time people have been saying, well, we should just regulate bad performance. And that's a really easy thing to say, but it turns out it's a challenging thing to figure out. And there are two things that are needed. One is to decide how to measure performance. What do you do physically to measure performance? A lot of people think, well that's simple. You go to batting cage, hit some balls and you're done, done well, people aren't very repeatable and you can't control things in a batting cage. So that just doesn't work. You've gotta do it in a laboratory and you've gotta do it with, with controlled machines. There are lots of ways you could still do that, but there are really probably three that are the most practical.

(29:28):

And a STM has zeroed in on the one that I think is, is the best, where we fire a ball at a stationary bat and allow the bat to recoil and we set up the test so that the relative speed between the bat and the ball is the same that you'd have in play. And that's something we can do in a fairly straightforward method in the laboratory and it's pretty repeatable. So that's been worked out and we do that. The number of labs do that. The other part of the question that is actually more tricky, once you've done that, how do you quantify it? What do you measure? What number is the number you want to use to quantify performance? A lot of really smart people have looked at this and it's taken about 20 years to get the answer right. And the first first answers were wrong.

(30:19):

The, the standard was put in place, but it didn't really work very well. It didn't correlate with field performance very well. So we continued to iterate. We looked at what we were doing both in our methodology and in the data that we were reducing and identified the shortcomings. And now we have a standard that's very rigorous and, and works quite well. But when we talk about measuring performance and quantifying it, scientists can't give the total answer there. There are two things that sport federations have to provide. They need to tell us, one, what is their goal? What are they concerned about? Are they trying to match something that they like, like for college baseball, they like wood and they want their standard to be would like, and that gives us a direction for what to measure for that goal. Other federations are more worried about how fast the ball is being hit in play.

(31:14):

Turns out that not all wood bats hit the ball at the same speed, it actually changes. So if your goal is to control the exit speed, then there's another path you take, another way you calculate performance, both the right, they just have different objectives. Then the the other thing federations do is decide the speed limit. We now have methodology. We have a process to calculate a value. Then somebody has to decide what that value has to be. And we should not do that as a governing body, uh, as, as a standards body that should be the federations. And so we go to them and they decide where they want play to be and develop methodologies to then measure those values and, and compare it to the limits that they provide.

Dave Walsh (31:55):

Yeah, I guess so to be a hundred percent clear then this test method can be used for whatever you would like the result to be for your organization, I assume.

Lloyd Smith (32:03):

Exactly. And for 2219, it's actually pretty amazing how broad it is and how widely it has been adopted. In fact, it's actually now being used for pickleball. So it's a testament to the work that's gone into developing a standard, uh, to, to how rigorous it is and, and how broadly it can be applied.

Dave Walsh (32:22):

And Nick, what are your experiences with this standard? And, and you, I know you test with it regularly, I'm sure.

Nick Smith (32:28):

Yeah, something that maybe I didn't think about as much when I first got involved in this. Lloyd mentioned that we test at a speed relevant to play. So since we're keeping the bat stationary, that means we're throwing the ball effectively twice as fast. It depends exactly what we're trying to replicate. But anyway, the ball speed is increased to make up for that, but that speed matters. So we test, you know, for youth federation, we're pitching our ball at a hundred miles an hour, whereas for, uh, college federation, we're pitching the ball at closer to 140 miles an hour to make up for those different speeds in play. Um, what I find interesting is how much that can change things. We were doing some work with a ball and it was, this wasn't off of a bat, we were just measuring the ball's, coefficient restitution off a flat wall and we were varying the speed.

(33:24):

And this particular ball, if we increased the speed from 40 miles an hour to 80 miles an hour, the coefficient restitution was cut by more than half. So that means we were pitching the ball twice as fast, throwing it twice as hard against the wall, and it was coming back slower. That's how much the ball's properties were changing as a result of the speed. So it's, it's very important that we get the speed right in the test to be, for it to be relevant to whatever the governing body wants to do. If we were doing a speed that was way too slow, we would be measuring something accurately for that speed, but it would be completely irrelevant to what was happening out in the field in that sport.

Dave Walsh (34:10):

This is fascinating for a youth baseball dad like myself. And I'm sure it'll be interesting to our listeners because I know that the feeling out there is change the bats and it's all said and done, but there's so many other factors as you're talking about, with not just the bat itself, but but the speed of the pitch, the sea height of the pitch, the, you know, it just goes on and on. So the standards you've been talking about and others that you've worked on, uh, have all emerged from ASTMs consensus process, which is something that the organization's very proud of. They bring in stakeholders from across all perspectives. So how would you say ASTMs consensus process has helped the field of baseball standards? Has it streamlined it, has it led to more robust or higher quality standards? What impact has that had?

Lloyd Smith (34:49):

It's provided opportunities for loss of discussion, but I would say that it significantly helped the process and where we're at. When you come to a meeting like this, people have different ideas and so there's always compromise that has to be reached to be able to come up with a standard that's then approved in the end. That can be painful at times as you try to get minds coming together. But I look at standards that have been developed in, in other ways. There are sports who develop their own standards and they don't have this consensus building process. And I've been surprised at how many silly mistakes they make. So I think very often it's better to take a slower and and more intentional pace, bringing in the, the input of others who have different perspectives to develop your methodology. And while that may slow your process, in the end, it's going to be a result that's gonna be more universal. And I, I think 2219 is just a testament to that. There was a lot of debate on how that standard should work, what the tolerances should be and, and what the equipment should be. Just a number of things that went into that. But now at the end, everybody likes it and it's used now for many sports.

Dave Walsh (36:00):

And Nick, what have your experiences been with, uh, ASTMs process?

Nick Smith (36:04):

I'm actually relatively new to ASTMs process, so I've been involved with A STM for about three years and, and all the standards we've dealt with in our baseball subcommittee have really already reached a consensus at that point. But what's fun right now, I was just on a subcommittee for pickleball. We've mentioned already they're using 2219 a little bit right now, but they have many more standards they're trying to develop and come to this consensus for their sport. So it's great to see, as Lloyd is saying, see the different stakeholders involved and see this, this process to get people to, to come together. And it, it really does lead to a standard that everyone can have confidence in. 'cause they were all part of giving their input to develop the standard.

Lloyd Smith (36:47):

One thing that I find really productive about the A STM meeting is it's a unique opportunity for people to come together. So when we developed a standard, we have the users, which are gonna be the federations and the test lab, and you have the manufacturers and they're the ones that are trying to design around it. Manufacturers tend to operate in their own circles. Federations tend to operate in their own circles and test labs tend to operate in their circles and academics in their circles. There's not a lot of opportunity for all these groups to come together at one time to have these discussions. And A STM has been a really productive time for that to happen and has invigorated this consensus process.

Dave Walsh (37:32):

Yeah. Well, you know, ironically, Nick mentioning pickleball kind of leads me into my next question. That's sort of a form of a new technology that came along. A, a pickleball racket is different than a baseball bat. And now as you mentioned, they're sort of revising and adapting those standards. So my question then with baseball and softball in mind is what new technologies or innovations are on the way in the coming years that could impact the games and that may need updated or new standards? A few years ago, no one could have imagined the impact that composite metals would have on the game of baseball. When I was younger, it was a solid aluminum bat. And, and that was what we used. They brought along these composite bats and suddenly, as we were saying, little League World Series has 65 home runs in, in a few games. It was just kind of amazing. So what are some of those new technologies that you see coming down the, the road?

Nick Smith (38:18):

Maybe Lloyd has some idea. I I don't have any idea of what new technologies would be coming into baseball bats. I know with composite bats, we had to adjust our test a little bit because the layers would break down in the bat. And so we, we have a method now to break the bats in and, and keep testing them. Yeah. Lloyd, do you have any ideas?

Lloyd Smith (38:40):

I would call this to some extent it's like spy versus spy as as soon as we come up with a methodology to control one parameter, we have manufacturers going out and coming up with, with something around that. So in baseball, this has happened in a number of different ways. Uh, Nick has mentioned with composite bats, uh, they tend to break in over time. And this is an interesting phenomenon where a bat breaks in, you would think, well, it's of lower value. It turns out the opposite is true. As composite bats break in, they become softer and their performance increases. So we have to then have a, a process not only to test what the performance of a bat is, but what its performance is over its lifetime. Another thing that came in from manufacturers, again, I thought was really incredible is a bat. We call it a, a non-linear bat, but what they do is they make the bat from two concentric shells.

(39:32):

There are two tubes in the barrel of the bat, and there's a small air gap between these two shells. What that means is if you're a a player that doesn't swing the bat very fast, then the barrel's not gonna deform very much. And you're essentially only using the outer barrel of the bat, which is the thin barrel and really high performing. While if you are a strong hitter and you swing the bat really fast, then both barrels get engaged, you end up with a, a stiffer barrel and your performance goes down. Our test is designed for a strong hitter strong, so we certify bats based on the deformation of both barrels. But this design allows players that don't hit the ball hard to end up with a higher performing bat. So that was something we saw coming and we went to the federations and said, watch out.

(40:25):

And the federations, most of them pretty much said, we kinda like this idea, so we're, we're okay with it. But there are innovations like that that happen all the time where we say, Ooh, okay, here's something we hadn't thought about, but how's this going to work? And there are other smaller details that we worry about in the test, and this is something Nick is working on right now, but not to put your readers too far asleep, but in a bat ball collision, momentum is conserved. That means the momentum before impact is the same as the momentum after impact. And we're able to use that to find out how repeatable and accurate our test is. And we're looking at different pieces of equipment in our experiment that we think might be losing a little bit of momentum to make that more repeatable. So there's small little adjustments. We're working on the test to, to try to help it be more repeatable. And manufacturers are very interested in that because then that lowers the likelihood that they'll have a product that will be banned based on non-compliance and experimental repeatability.

Dave Walsh (41:32):

We're kind of closing in on the end of our time here, but I did have one more question and it kind of is a general one. We are always looking for the next generation of members at A STM. And I know every profession, including yours, is looking for the next generation of engineers and scientists. And this is open to both of you. What advice would you give to a younger professional starting out in your field of material science or mechanical engineering? Would you advise them to join A STM and engage the standards development process?

Lloyd Smith (41:59):

I absolutely would, and I would go a little younger than that still. The first thing I would encourage is any person who's excited about science and sport should look at making that their career. A lot of people do that. We call it sport engineering. And it's fun to see how science and engineering interact with so many things we do in life. And, and sport is absolutely no exception. We have a society called the International Sports Engineering Association, where people like us come together and A STM is a wonderful way to get involved. We've been talking just about the standards that go along with, with mostly bat performance and ball performance, but there are so many other aspects of sport which are so fascinating. There's a very active group that is concerned about personal safety, helmets, head protection. There's a lot of really groundbreaking and important research that's happening in that group. So there's just a lot of, of fun and exciting things to be doing in sports, sports engineering, and ASTM as a really great place to, to meet people, interact with them, and, and share ideas and results of your work.

Nick Smith (43:08):

I'll just reiterate that and highlighting some things we've talked about before. A lot of times when I'm doing my own work, I kind of get tunnel vision. I'm focused on just what I need to be doing and what I want to get out of it. And at A STM where you're meeting people that have different goals and you're talking about these things and coming together, it, it forces you to broaden your perspective a little bit. So I, I think joining a group like ASTM is really important for that.

Dave Walsh (43:35):

Well, I think we could talk about this for several more hours. We barely scratched the surface, but Lloyd and Nick, thank you for being with us today. We really appreciate your time. Thanks for having us. You're very welcome. If you wanna learn more about any of the standards discussed in this episode, visit astm.org for all the latest. And if you enjoyed the show, remember to like and subscribe so you never miss an episode. I'm Dave Walsh, and this has been Standards Impact presented by ASTM International.