Well, thanks so much to the AOSSM for the opportunity to present my research and this algorithm that we've worked out. I'm from the University of Utah in Salt Lake City. I have some disclosures. The ones that are really relevant is that some of the research I'm presenting has been funded by the Major League Baseball, so we're thankful for their support to try and figure this out. So what you need to know from the basic perspective about the pitch is that the energy is created by the stride as well as by the rotation of the hips and the shoulders, and the arm basically serves as a conduit for that energy onto the ball. So the arm here is taking the energy already created and then translating it onto the ball largely. So from a physics perspective, therefore, that ball for velocity, the energy for velocity has got to come from that motion. It's got to come through the arm. And injury from that motion is common. I think a lot of people in the room know this, but 30 to 40% of youth pitchers are going to be injured at some point during their high school or youth careers. How do we prevent these injuries? And that's really what we're talking about with workload management is injury prevention. So I think we all owe a debt to Glenn Fleisig for the work he did to determine the pitch count recommendations that certainly we've seen some research on today. And I will say that while they're great, they certainly have not solved the injury pandemic, that we're seeing an increased number of injuries despite people following these recommendations. I see this in clinic just like I'm sure everyone else does. I see the kid who comes in with his father at UC Altair, and his dad says, Doc, how is this possible? We followed all of your rules and still my son's elbow's torn. So what I'd like to talk about is how we get beyond this to do even better. And the first thing that we've done that I think really helps us is to understand that not all pitches are created equal. So if you have a pitch that's at a higher velocity, the energy for that velocity has to come from somewhere, and it comes through energy, again, from that stride and rotation that then's translated through the arm. That's increased energy through the arm when you throw a higher velocity pitch, and it's therefore associated with a higher risk for injury. We've shown this in youth pitchers, and we've also shown it in major league pitchers where there is this dose response relationship between velocity and injury. The other thing that correlates is weight. So if you have a heavier pitcher, it's a heavier forearm. To translate that forearm at a higher velocity, you've got to put more energy through your shoulder and your elbow. Well, the interesting thing is that over time, these things are increasing. Our pitchers, they're throwing harder, and they're getting bigger. So as those things are happening, we're seeing more and more injuries. And this has been shown also in biomechanical studies that these two factors really do correlate with how much stress you put through your elbow. And this is just physics. I mean, it's not hard to understand that if you want to throw harder, if you want to throw with a heavier arm, you've got to put more stress through your elbow. So I think that's factor number one for workload management. Understand not all pitches are created equal. If you throw harder, if you throw with a bigger pitcher, you're at a higher risk with the same pitch count. The other thing that matters here, though, is workload. And I wanted to really delve into the details with this. So we've recently worked through Major League Baseball's data. We looked at the 370 UCL tears they had in the past six years, and we correlated the games played before those tears as compared to control pitchers who'd never torn their elbows. And what you see is that there actually is a difference in terms of how many innings pitched and batters faced. The pitchers who have tears, they've faced more batters. And in addition, they've pitched more innings. It's not a huge difference, but it is a difference. The interesting thing is that it's even more fine than that. If you look at the pitchers who'd sustained a UCL tear, and if you look at how much they pitched in the two weeks prior to injury as compared to their own baseline, i.e. three months, greater than three months prior to injury, there's even an acute bump, again, a small one, about one more batter, about a third of an inning. But those things do matter. And this is where the rubber really hits the road, is if you try and take those pitchers and understand over the course of a game, where does the injury risk start to rise? And what we found in that data is that if you pitch for three innings or less, your injury risk is about the same. As soon as you get beyond three innings, each additional inning adds to your risk. As soon as you get beyond 15 batters, each additional batter adds to your risk. So the reason that I think this is interesting is it gets to this thing at the heart of the way we manage our baseball players, which is that they're divided into starters and relievers. So we have starters that try and go as deep into the game as they can go, and those people are at a dramatically increased risk for injury, with a relative risk of about 1.5, as compared to relievers, who often only pitch for two to three innings. And this plays out in our days rest data, whereas if you look at the people that have five days rest, there's an increased risk for injury. That's not because rest is bad. In fact, we know from Glenn Fleiss's work that days rest are important. And if you have pitching on back-to-back days, that is harmful. So I think this plays out that we need to understand when we talk about workload, that we have this tradition in baseball for starters and relievers, and it's probably pushing us towards having pitchers pitch for longer, and that's probably harmful to them. I think the last thing to understand here is that there's a balance when you talk about workload management. So we did this study with the Angels where we took pitchers and we ultrasounded their elbows at the beginning of the season, i.e. in spring training, at the end of the season, the beginning of the next season. And through that work, we're then able to understand how thick is the ligament and how does that thickness change, as well as how lax is the ligament, i.e. how long is it? And when you stress the elbow, how much does the elbow open? And the thing we found, which I did not expect to find but was interesting, is that during the course of the season, the ligament gets thicker, and then during the course of the off-season, the ligaments get thinner, and they're actually a mirror image. There's the same thickness and thinness increase. This suggests to me that the ligament is adapting to stress. So when you stress your elbow as a pitcher, your ligament adapts. It gets thicker, and in addition, it gets longer. That thicker, longer ligament, sorry, that's a tongue twister, really allows that ligament to better adapt to stress. And we've known this for a long time in bone. Everybody in the room knows, when you've worked with bone, that that little old lady who lies in bed, her bones wither away, and our astronauts, we send to space. That's the reason why they have to run on treadmills, otherwise they've got osteoporosis. The same thing happens in the arm. This is a study Glenn Fleissig did that showed that, where if you look at the dominant as compared to the non-dominant arms and throwers, even years later, you can see differences in adaptations in the humerus. You can see the humerus, the bone, the cortex itself is thicker. But not only that, it actually remodels from being a triangle, which is better for resisting bending stresses, to being a circle, which is better for resisting torsional stresses. The same thing is happening in our pitcher's arms when they pitch. It's not just their bone, it's also the UCLs, it's also the rotator cuffs. It's all of the other tissues that are adapting. So workload management has got to be a balance. We've got to pitch our pitchers so that they can have enough strength that they're able to withstand the stresses of pitching. Thank you. Any questions before we close up? Peter, I'll ask one question. I think another thing that's really important, and that's great work, is what defines a day's rest? One guy might not pick up a baseball, another might throw long toss 300 feet, but he's counted as a day's rest because he's not actually throwing in a game. So I think that that's something interesting too to look at, or maybe you did. Yeah, absolutely. I could not agree with you more that when we talk to our pitchers about long toss, a lot of them think of that as rest. But there's great biomechanical evidence from two different studies now to suggest that long toss is just as much stress to your elbows pitching. So definitely a day off is not necessarily a long toss day. Yeah. Dr. Taylor? Stay there, Peter. I got a question for you too. So it's interesting to see the adaptive changes in the thickening and lengthening of the ligament throughout the course of the season. Would that suggest to you that potentially something more protective could be done in the way that we train in the off season in order to maintain the protective morphologic changes at the UCL? Yeah, I think that's a great idea. We need to figure out how to do that. I think if you look at the way we train our pitchers right now, we don't have anything we do that trains the UCL that isn't throwing. I think that we should figure that out. I'm sure there are other ways that we could stress the ligament that don't involve throwing, but we need to invent those things and then test them to show that they actually work. Pretty sure Dr. Conway will figure that one for us. Yeah. So John Wooden said if you want to jump high, you have to jump. If you want to throw hard, you have to throw, but your point's well taken. The question I wanted to ask is if in the two weeks prior to their injury compared to the 12 weeks prior to that, they have an increase in the number of batters they're facing, do you think that increased workload is actually a decrease in performance that they've yet not appreciated as actually ligament insufficiency that's occurring? And the reason those two weeks are actually heralding their tear or their injury as opposed to they've had a required increased workload. So which is it? Is it they've just ramped up their workload and then they had an injury or is that workload because they're having to face more batters to get through an inning because they've had decline in performance? Does that make sense? Yeah. I think it's a great point and one we're going to need to tease out. We have some next steps to try and tease that out because I think it's a really interesting idea. There's actually a poster showing that there is a correlation between wins above replacement in injury, which I think is super interesting to think, but it's the opposite of what you suggest. It shows that players that have higher performance are more at risk for injury. So we need to, I think that can be teased out with performance data, but it's going to take some work. Yeah. Oh, thanks. All right. Thanks everybody for coming. They wanted us to make sure that you know that there's a reception in the exhibition hall starting right after this session. Thank you. Great job.

workload management

pitchers

injuries

velocity

ligament strength