Thank you very much to AOSSM for this opportunity. If you were here for Brittany's expertise, sadly, you're stuck with a third year medical student from Rush Medical College today. On behalf of the Grant Garagus Research Team, I'll be talking about the relationship between arm path, ball velocity, and elbow varus torque in professional baseball pitchers. Once the slides advance. Can you advance? There we go. Okay. Oh, sounds good. So as I'm sure many of you know who watch baseball over the past 10 years, the rate of fastballs thrown over 95 miles per hour in MLB pitchers has increased from 12% to 22.1%. And it should come to no surprise that the steady climb in fastball velocity has also been accompanied by increasingly common shoulder and elbow injuries. The active throwing of baseball is one of the most violent motions that any human can do, placing especially high kinetic loads on the throwing arm, especially elbow varus torque. Here's a picture of Michael Kopech, one of our White Sox pitchers. On the left was pre-UCL, he was a fireball thrower, and he since has gotten UCL surgery as well as bulked up a little bit, as you can see by the picture. Next slide, please. So in talking about arm path, it's defined as the distance the arm takes from the glove to ball release. So in a given pitching motion, obviously the baseball starts in your glove. And so what we mean by this is the moment that the ball leaves the glove to the moment that you're actually releasing the ball. Traditionally, pitchers have been taught to throw with a longer arm path during the first phase of the pitching motion. And anecdotally, up until recently, it's been thought that a shorter arm path places increased stress on the throwing arm and could be harmful. Next slide, please. However, there's recently been a change in philosophy for pitchers to shorten their arm path and attempts to decrease injury risk and optimize ball velocity. Twitter can be a beautiful thing for discourse about a variety of different topics, one of them being baseball mechanics. But when people are suggesting certain things, for example, usually it can lack peer-reviewed data and data behind that. But pitching instructors suggest that the shorter arm path allows for better sequencing of the body segments and more efficient transfer of energy through the kinetic chain. So theoretically, this combination ultimately produces increased ball velocity with decreased elbow various torque experience at the throwing arm. Next slide, please. And then click two more times, please. So on this left side is Lucas Giolito, one of our White Sox pitchers. He was one of the most touted prospects in baseball when he did come up, but you can see it's a much longer arc range of motion from when the ball leaves his glove to actual release of the ball. And on the right, this is Lucas Giolito in 2020 having a no-hitter. You can tell just anecdotally that it's a much shorter arm path and much more condensed. Next slide, please. So for our methods for the study, we used data from MODIS Global. It was a retrospective review that identified 320 baseball players, 189 were included in our analysis. Each pitcher threw eight to 12 fastballs using 3D motion capture analysis. And a linear regression model was used to assess inter-pitcher relationship between the arm paths, elbow various torque, and ball velocity. And a linear mixed effects model with random intercepts was used to assess intra-pitcher relationships. Next slide, please. And so we defined the pitching motion in three phases. The first phase was the maximum knee height. So whatever that is for a given pitcher, depending on their motion. Foot contact was defined as the .01 seconds when either their heel or toe initially touched the ground. And then ball release was that initial moment when their arm finally crossed the positive X direction, because at that point, they then have to release their ball. So early and late, early maximum knee height to foot contact, late foot contact to ball release, and then total, put them all together. Next slide, please. And so for our 182 pitchers, average was 10.5 pitches per pitcher, ball velocity 38.7 meters per second, which comes out to about 86 miles per hour. We'll get more into what exactly the elbow various torque and the total arm path means in a second. Next slide, please. And one more. So when we're looking at inner pitcher comparison, meaning between two pitchers, the only things that were statistically significant from a P-value was both the early and total elbow various torque. Ball velocity, there was no significance whatsoever. And even for the two significant values of early elbow various torque and total elbow various torque, these R-squared values were very small. Next slide, please. But when we looked at between a given pitcher, between those eight to 12 pitches that they were throwing, we found much stronger data. So both the early and total elbow various torque were significant once again. And each phase of the pitching motion was significant for velocities with much stronger R-squared values. Next slide, please. And in general, for every 30 centimeters, 11.8 inches increase in early arm path, the average range for an individual pitcher, there was a 1.29 Newton increase in elbow various torque and a 0.354 meter per second increase in ball velocity. Next slide, please. So obviously, in a given arm path, there are a myriad of different components, including elbow flexion, shoulder rotation, shoulder horizontal abduction, and these all contribute to elbow various torque. Previous research to this point has only investigated arm movement starting at foot contact because this is the time where all of our energy that is then in the air is being imparted on the ground. But it's possible we're missing impacts on the throwing motion by doing this, which we think that our research has showed. Slight variation in pitching mechanics between throws can be protective. If a given player redoes the same pitching motion over and over again, it's putting that same amount of torque on each muscle every single pitch, which can be harmful. Arm path did correspond to increase in elbow various torque and increases in ball velocity. And overall, optimization of a given pitcher's mechanics may not necessarily require a major overhaul, but rather minor tweaks to emphasize efficiency of movement. Next slide, please. So in conclusion, longer arm path is a weak predictor of elbow various torque and ball velocity experience among professional pitchers. When controlling for an individual pitcher, arm path is a strong predictor of both elbow various torque and ball velocity, indicating longer arm path, the greater the ball velocity and elbow various torque. Determining the individual mechanics that lead to decreased elbow various torque may help coaches and trainers to correct these patterns. And just anecdotally, for example, there's a pitcher on the University of Tennessee baseball team named Ben Joyce, who you may know throws about 104 to 105 miles per hour. Just hypothetically, he probably will get drafted to the major leagues. Wanting to optimize his pitching motion may potentially be detrimental because now his body habit is, as well as the muscles, have adapted in ordering him to be allowed to throw that fast velocity, where it may not be a one-size-fits-all, there's this ideal motion for every individual player, but rather small tweaks in an intra-pitcher comparison can yield better results. And thank you.

arm path

ball velocity

elbow varus torque

MLB pitchers

shoulder and elbow injuries