Transcript of Interview with Kristen Nicholson: The Science of Athletes in Motion

This is a transcript of the video titled Kristen Nicholson: The Science of Athletes in Motion

Welcome to Inside Science Conversations. I'm your host, Chris Gorski. I'm the senior editor at Inside, a science news website published by the American Institute of Physics. This is a show about what makes scientists tick, what inspires them, and what they want to do. Today, we're talking to Kristen Nicholson. She's an assistant professor of orthopedic surgery, and the director of the pitching lab at Wake Forest University. Kristen, thanks for joining me. I'm excited to talk about all the work that you've done with baseball, and maybe we can even touch on some of the other things you've done. But first, I wanted to find out when you were a kid elementary school going into middle school, what did you think you might do as a career? If you even thought about that?

Kristen Nicholson 00:55

Yeah, I don't know that I was ever set on anything. I guess I thought I was going to do something with animals. Maybe as zoologist something along those lines. I even formed a little club with some of my friends. We call it the animal career club. And we would meet in their backyard and discuss different careers and animals, I guess. And I, you know, ironically, I don't think any of us have careers in animals. But that was what we found interesting as elementary school kids.

Chris Gorski  01:29

That's really neat. And so when did science become something specifically that you wanted to pursue?

Kristen Nicholson 01:39

Yeah, I think I've always been interested in you know, science and math and physics. And in high school, I liked the science fields. And then I also liked just being outside and in the environment. So as a freshman, I actually was an environmental science major. And then I went through that first semester of college and realized that I was never going to have to take a math class. And I was like, I kind of missed that. I was like, I was disappointed that I wasn't going to get to take math. And so then I was like, well, maybe I should be a math major. And so I switched my major and ended up being a math with, you know, applied math as my focus. And my undergrad degree is in pure math.

Chris Gorski  02:31

Okay, so that's interesting to hear. So you did math? And then how did you decide what was next?

Kristen Nicholson 02:41

So I did math, and it was fun. And I'm glad that I got to take some math classes. But I didn't necessarily love you sitting down and solving math problems, I didn't really see kind of the benefit in the applicability of that. So I was applied math. And so I was just kind of looking for you a more hands on something you could do with math. And I had an internship at NASA actually. And I was writing a computer program that I think was to math heavy for the computer science people. And, and that was kind of the trajectory that my career looked like it was going. And again, I didn't love just sitting by myself on the computer, you know, writing computer programs, solving math problems. And so at the time, I personally, have always been also athletic and active. And like I said, like being outside, I ran cross country, and track in high school and my freshman year of college, and then I switched to doing triathlons. And so I was looking for something that maybe I could combine my love for sports and athleticism, and math. And so I stumbled upon biomechanics, which is essentially physics of the human body. And so I had an REU research experience for undergraduates at the Cleveland Clinic in biomechanics, and I was looking at finding optimal walking gait that would minimize energy expenditure or minimize fatigue. And, you know, I just kind of fell in love with the idea of biomechanics, and able to combine kind of that math and athleticism and physics and science and decided to pursue a master's in PhD in biomechanics. So that's kind of the trajectory I went maybe not the most traditional.

Chris Gorski  04:41

man, that's really interesting, though. So you're, you're when you're studying the walking gait. What's the kind of purpose of that is that with people who are having trouble walking and trying to figure out how to minimize the energy they need or is it something else?

Kristen Nicholson 04:57

So as an undergrad in, my first kind of like experience into biomechanics, it was just general biomechanics. So I was using MATLAB and some optimization programs and just equations of physics and equations of motion to, to optimize this mathematical calculation of gait and walking. But in grad school, I found myself getting more and more involved in this motion analysis and the motion capture, which I'm sure we'll talk about in a little bit. But the main goal of kind of motion capture and biomechanics are the… original uses was for gait, and for helping kids, mostly kids with like cerebral palsy or muscular dystrophy that have some functional movement disorder. And so you can use the biomechanics and the optimizations and all the calculations to help inform orthotics or surgery recommendations. I know in your last episode, you talked a lot about running. So you can even use the biomechanics and the equations to optimize your running patterns to use less energy or induce less fatigue so that you can be more efficient runner, faster times use less energy, things like that.

Chris Gorski  06:22

So how did you decide on what to do when you were in grad school, what kind of problems to investigate.

Kristen Nicholson 06:28

I came into grad school thinking I wanted to do you know that combo of math and athletics and performance analysis, I was a triathlete myself. So I was kind of thinking more along the lines of the running analysis and how to optimize that kind of stuff. And my advisor told me that we could do the sports and we could do the athletics, for fun, but that all of the funding and the money and everything was going to be in the more clinical side of biomechanics or motion analysis. And so I took his advice. And ironically, all of my grad school was paid for by a project that we did with US figure skating. So there is some money in the sports. But I did focus on a more clinical project for my dissertation. And so my advisor, had a really close working relationship with some of the orthopedic surgeons at the Shriners Hospital in Philadelphia. And they dealt a lot with children with brachial plexus birth injuries. And what they found was that it was really difficult to measure what the shoulder blade is doing. Because traditional motion capture and motion analysis works by, you put retro reflective markers on different body parts. And then the cameras just record the positions of the markers. And so then, using math and physics, you're able to create coordinate systems for your different body segments. And then find the angles and velocities of the different joint angles, by using that 3D motion analysis. That doesn't work for the scapula or the shoulder blade, because if you put markers on your shoulder blade, and then you move your arm, the shoulder blade moves underneath the skin. And so the markers don't actually follow the motion of the shoulder blade. And so, our lab was really focused on trying to solve this problem figuring out new and innovative ways that you could use the traditional motion capture to measure sciatica function and orientation. And specifically in these kids with brachial plexus injuries, their shoulder joint, so that where the scapula meets the upper arm, or the humerus is as fused, and so they use their scapula to compensate and gain that motion. So like if I asked you to bring your hand to your mouth, you're going to kind of go like this, do it or whatever. But they don't have this motion of the humerus against the scapula. And so they're they use their whole shoulder, their whole scapula will wing out in order to get their arm kind of across their body in their hand to their mouth, I used mathematical modeling. So linear regression and also some machine learning type modeling. So way took the shoulder blades orientation in several different like static postures, and then use mathematical modeling to model what it would be doing functionally based on where your upper arm in that one spot on the shoulder blade are. And it works well for all the adults and it works okay for the kids with the brachial plexus injuries as well. And then one of my colleagues is actually continuing that and trying to apply it to baseball. And so it's ongoing, but it's promising.

Chris Gorski  09:59

I'm kind of fascinated whatever tie in there might be between the things you learned there and what you brought to figure skating. But more kind of to the, to the point is that how you got the expertise that made it possible for you to work with baseball players.

Kristen Nicholson 10:16

So I would say I'm an expert in kind of motion analysis, not necessarily like some aspects of biomechanics contain, you know, bone strength and muscle strength in and more like granular mechanic type stuff. But I would say I'm more of a motion analysis expert. And as I mentioned before, the traditional uses of motion analysis are for like gait pathologies, and walking and using it on functional movement disorders for the lower extremity. And there aren't a lot of people out there who use motion analysis for the upper extremity. And there's a couple different reasons for that. One being this really difficult problem of what is the scapular what does the shoulder plate doing, you can't measure that in the traditional ways. The other being that the shoulders a lot more mobile than, say, your hips or your knees, and your knees, especially, they only really move in one plane, your flexion extension, your hip does all three motions, flesh extension, abduction, intermix rotation, but primarily just kind of flexion extension when you're walking. But your shoulder can circumduct and you can get to the same end location, multiple different ways. And these all pose problems when you're trying to describe, you know what the arm is doing mathematically. And so a lot of people just kind of avoid the upper extremity and do their work on the lower extremity. And so by trying to tackle this problem of scapula orientation you in whether it's healthy adults or kids with brachial plexus injuries, I kind of became an upper extremity biomechanics expert. And so that allowed me to kind of transition into this this baseball position, just because there aren't very many upper extremity biomechanics out there.

Chris Gorski  12:17

Wow. So it was that kind of did that feel like a natural progression to you? Or did you Was it some kind of like leap of faith, I can, I can do really well with this, had you done baseball work before you got to Wake Forest?

Kristen Nicholson 12:31

I had not done baseball work. So my advisor had always been interested in baseball. And I think when he first got into biomechanics, you know, baseball was kind of a passion for him. And then he discovered that you couldn't really measure what the shoulder blade was doing. And that was a big problem. And so then he started venturing to tackling that problem. And that led him to this patient population at the Children's Hospital. And like we said, a lot of the money and funding you're going to find in these more clinical, and so he kind of built his career more around children and upper extremity about these clinical sides of it, while pushing his kind of love for baseball back. So, you know, we, his students always knew that he loved baseball, that was like his first passion in reason for kind of getting into biomechanics. But we never did any baseball research. You know, as his students. I did do the figure skating, as I said, and for the figure skating project, we actually were just looking at their in air motions. And so we had a program that would model what they actually did using the motion capture. And then you had a little figure that you could adjust their in air position and rerun the simulation. So this is what would have happened had you gotten into this other position. And so we were able to tell them what they needed to do and what different positions they needed to get in in order to complete the jumps that they were trying to land. And most of the time, it was just like, pull your arms in tighter, you'll spin faster. But being able to visualize it, I think was a really powerful tool for them. And then so then leaving grad school, I actually went and worked in one of those more traditional pediatric gait labs where we did a lot of work with the kids with cerebral palsy, muscular dystrophy, and skeletal dysplasia, and things like that. And I was always looking for an opportunity actually, just to change locations. So I went to grad school in Delaware, and I was working at the Children's Hospital in Delaware, but I'm from South Carolina. And so I was looking for an opportunity to come back home. And so this baseball opportunity presented itself and I actually worked for the hospital I worked for Wake Forest Baptist Health Center atrium Wake Forest Baptist Health. And I have like a dual appointment as the baseball team's bio mechanist. And so the hiring was done by the hospital. So I think that they really liked that I did have this clinical experience of working in this traditional gait lab. But I also had the sports experience from the figure skating. And then I was an upper extremity specialist. And so I think it was a leap of faith for the baseball team. You know, the head coach recently said, you know, he was looking at my resume, and it said, figure skating and, you know, scapula mechanics and everything. And he was kind of like, I don't know, is this the right person. But I think that the hospital convinced them that, you know, kind of that technical math background combined with the motion capture expertise, combined with being an upper extremity expert, would allow me to fill the role that they were looking for.

Chris Gorski  16:00

So Well, how's it working out?

Kristen Nicholson 16:03

Yeah, I mean, it's definitely been interesting. Um, I would have probably been the last person to say that this is where I would have ended up three years ago. But I was kind of thrust into this as maybe an upper extremity motion capture expert, but by no means a baseball expert. I mean, I like baseball, I would go to the minor league games with my family growing up as a kid, but definitely not a baseball expert by any means. And so it's been a big learning curve. I've surrounded myself with good people who are interested in the biomechanics, but really know the kind of coaching aspect of it, they've kind of really helped tie in the baseball lingo and everything with the biomechanics. I think we've built a really great team here, and a lot of people are interested in what we're doing. And yeah, we're pushing forward. And it's been exciting.

Chris Gorski  17:05

That's neat. What kinds of things do you do you do with the baseball players?

Kristen Nicholson 17:12

Yeah, so we have a full state of the art biomechanics laboratory, we have the motion capture cameras, we also have some markerless cameras. We have force plates in our mound, and then we have the traditional like ball tracking devices. And so we've really been offering pitching evaluations for anybody that wants to come and get a pitching evaluation. And we also use it as a player development tool for the Wake Forest baseball players. They're able to get kind of the full analysis several times a year, and then they can use the markerless system almost weekly to see their progression. And so, up until this point, I feel like we've really kind of just been trying to build our database of pitchers that we have available to do the research and discover the problems and kind of solve the issues. I think to date, we've seen about maybe 350 pitchers, all the way from 12, up to some professional level pitchers. And so that has enabled us to really start to explore some of these mysteries behind pitching. And so we'd like to say that you just like with running, there's this idea of like running economy or running efficiency where you can perform at a certain rate while minimizing kind of your energy expenditure, so that you can keep going and optimize your performance. And so that's kind of what we're looking for with baseball, too. We want to limit the stresses on the arm. And that's the big thing that that Tommy John surgeries, those UCL reconstructions are becoming more and more popular and at younger and younger ages. And so we look at that as the stress on the UCL or the elbow torque, and we want to minimize that. And then shoulder issues are a big problem to rotator cuff tears in injuries and impingement and things like that. So we kind of look at that shoulder distraction force, the force that's keeping the upper arm from essentially pulling out of the shoulder socket. We want to try to minimize that. And so we're trying to look at all the different mechanics and pitching skills and everything that you can alter and adjust to minimize those forces on the shoulder and the torques on the elbow. But at the same time, we don't want to limit their pitching velocity. You know, that's the goal, you know, that they're all chasing is a high pitching velocity. And so we have to figure out what we can do in terms of their biomechanics, in order to maintain or increase pitching velocity while decreasing those stresses on the elbow and on the shoulder.

Chris Gorski  20:06

Yeah, I wanted to ask more about that, because my understanding from talking to people over the years is that if you're throwing 95 or 100 miles an hour, you're basically maxing out everything the body has, from the tendons to the muscles to everything else in, in search of that speed of the pitch, right? And so, you know, if somebody comes in and says, I'm not throwing as fast as I used to, can you help me understand why or if they're saying, I just really think I should be able to throw 97 instead of 95 miles an hour? You know, are you trying to help solve that problem specifically? Are you looking at it holistically? What, you know, you know, I'm fascinated by this.

Kristen Nicholson 20:49

I mean, we kind of look at it holistically, like, the Holy Grail here is this, you know, efficiency term that that is kind of elusive. But, you know, can you limit the stresses on the shoulder and the elbow while still increasing pitching velocity. But, you know, my approach, and maybe this is coming from more the clinical side or clinical background is that if they're injured, they can't pitch at all. And so, you know, what's the point in getting somebody to throw 100 miles per hour, if they're going to blow out their elbow? Then it doesn't matter. So we got to keep them healthy in order to keep them on the field. And then we can focus on increasing their performance. And this efficiency kind of goes hand in hand. If you're moving your body efficiently, that's limiting the stresses on the elbow and the shoulder. But it's still going to be able to produce those high velocities, because you're efficient, you're creating energy, transferring it through the body efficiently, and then through to the ball. And there's not any hang ups, not causing the extra stress on the elbow, and the shoulder. And so you shouldn't be able to theoretically, do both, you should be able to throw harder and increase your velocity while still staying healthy.

Chris Gorski  22:15

And how do people, you know, obviously, if a pitcher a young pitcher, a college student, you know, a baseball player comes in and wants to get evaluated, obviously, they're interested, but is there a big variation and how receptive they are to the messages you might have? You know, are you able to take these medical insights, biomechanics insights, and kind of translate them to baseball lingo or something that a coach or player understands really well that they can grasp?


Yeah, I mean, I think that that has definitely been a learning process for myself, especially having not been a baseball expert and understanding the baseball lingo. But again, I've surrounded myself with, you know, some people who have taken an interest in the biomechanics, but also know that other lingo, you the pitching coaches that we've had come through Wake Forest, Matt Hobbs, John Hendricks,  they've been great. And then we've also had some lab coordinators, and they have a background in like pitching and being a pitching coach, but they're also invested in the biomechanics and being kind of that liaison or that link between what I say and then what the player can actually do to kind of implement those changes and move forward. And so Evan Wise and Mike McFerrin have really been beneficial, I think, in making the lab applicable and the information usable. I will say, you know, the people that come in and get a pitching evaluation, we then kind of just throw everything at them, they get the biomechanics feedback from me, and they get some feedback from our athletic trainer, and they get some feedback from our strength and conditioning coach, and then the lab coordinator might be found we'll sit down and go through it and then explain like what they can kind of do. And I'm sure it's it's overwhelming, especially for the 12-year-olds, they probably mostly are just listening to the what can I do side of it. But when it comes to the Wake Forest University pitchers, we don't actually give them anything, I give it to the pitching coach. And then the pitching coach decides based on his knowledge of that player's, you know, personality and learning type, whether or not they need to see the raw data or whether or not they just need to know what drills to do. And I think it does depend on the player, you know, some of them, you want to know all the details and want to know if they're changing their ground reaction force by a certain amount, or they want to know if they're increasing their trunk rotational velocity And then there's other ones that if you told them specific numbers and specific things that they're trying to change, would get too caught up in their head on every single pitch on whether or not they're doing that, and then everything else would kind of get blown out way and it would not benefit them at all. And so you do need to kind of know the personality, and there is this little bit of give and take on what how much information you actually give them.

Chris Gorski  25:26

So there's so many kind of fine tuning questions that would go beyond efficiency of your particular pitcher's mechanics, right from, you know, I'm thinking about things like, you know, even the things that people might be thinking about right off the bat would be things like, Can I throw the ball faster? Can I spin it faster, more times, and it's wrapped to the plate. But there's also all these areas about, you know, fatigue, and what happens at fatigue? And what when somebody is tired after 75 or 100 or 19 pitches, or however many, right? How, you know, how that adds up over time, you know, both within a bout of pitching within a game, and then over a season or a career. Are there particular questions that you're looking at for research or, you know, people you work with are looking at, and how do you prioritize these things?

Kristen Nicholson 26:34

Yeah, there's definitely a lot of questions and a lot of things that you can look at. One thing is you prior to our lab, there was only a handful of other kind of labs like this. There's ASMI down in Alabama with Glenn [Flightstick.] They've been around for a long time, and they've offered these pitching evaluations, but they're associated with a hospital. So they've always just offered kind of pitching evaluations. And then driveline, baseball has a little bit of the 3D biomechanics, but they're your performance driven and for profit company. And so they're more like, how can we use this to increase your velocity type stuff, they're not doing research projects. And then a lot of the questions that that you've asked, and that you proposed have to do is you monitoring and something that that you couldn't do if you just had somebody come in for a pitching evaluation, and then they leave. And so as more and more kind of teams and facilities, I think put in these labs, those are questions that we can actually start to understand and start to look at. So our lab is attached to the Wake Forest baseball team complex. And then with as the technology advances, and you have more and more like markerless motion capture systems, they can use it for every single bullpen that they throw. And so then you can start to get that information about fatigue, you know, is it make a difference from one day to the next, you know, the different the bullpen after a game, and things along that nature or, or even just I mentioned earlier, what we're looking at is that elbow valgus torque and that shoulder or elbow, various torque and that shoulder distraction for us. Those are just assumptions. There's no good data that says, you this actually leads to injury, we just assume the more stress you put on your elbow, the likely more likely you are to be injured. But as we get more and more data and able to follow these players, you know more closely with repeat sessions, then we can actually start to answer the questions of, well, this is actually going to lead to an elbow injury. And this is actually going to lead to a shoulder injury, these are things we need to fix or these are things that are okay, if you built them up appropriately in questions like that. We did try to collect data on all of our starting pitchers immediately coming out of the game, to start to look at what their fatigue mechanics might look like. And we do have some of that data. But we were only able to do it for one season. And as most people are probably familiar that a team only has, you know, five or six starting pitchers. And so we only have five or six players worth of that fatigue data. But as we were able to get more I think we can start to look at that a little closer. There are also studies out there that have done like simulated games to try to look at how mechanics change with fatigue. But is a simulated game really as good as a game there's no like mental fatigue that you get with the game. So yeah, those are all questions that we're excited to just start to look at. As far as like what you prioritize, you know, I don't know, I  just kind of have to go with what I have and what resources I have. And as the lab grows, and we get more students and more data that those are all questions that we want to tackle and look at.

Chris Gorski  30:12

So you got a few things to figure out? Yeah, there's gonna be work to that. Have there been any particular surprises or especially rewarding things that you've been able to do in the last couple of years?

Kristen Nicholson 30:30

Yeah, I mean, um, it's been a challenge, the lab opened in January of 2019. And then we have one, probably solid year of being able to use it however we wanted to. And then as we know, this pandemic hit, and that kind of threw a wrench in everything that we wanted to do, and how often we were able to use it. And yeah, and then there's been a lot of turnover in the coaching staff and things like that. And so we've continued to kind of grow our database of pitchers that we're able to pull data from it and do things with. But we probably haven't been able to do everything that we that we wanted to do. In both in 2021, and 2020, we did have first round, draft picks come out of Wake Forest. So that was rewarding. You can look at their like very first motion analysis, to their very last motion analysis and see that they were able to kind of make some of those changes that we recommended. And so I would like to say that the lab played a part in in their success. I mean, they were very talented individuals anyway, they may have been first round picks without the lab. But I'd like to say we had a hand in helping them out. There has been less injuries on the Wake Forest team, compared to like the rest of the ACC or NCAA division one programs. So I'd like to say that we had kind of a part in that as well. And then yeah, I think the most surprising thing is that just the over the last three years, I've somehow become the baseball biomechanics expert, which I never would have expected. And MLB often comes to us and asks us to collaborate and we've done some stuff with them. And a couple of the teams have agreements where they send their players to us to get evaluated. So it's been fun and exciting.

Chris Gorski  32:34

Do you ever just sit back and think, How did how did I end up here?

Kristen Nicholson 32:38

Definitely all the time. And my I'm definitely like the introvert in the brain. And my husband actually is the one who says that he's kind of a mouse and the energy and he's having a great time. Being a baseball family now and in getting to where we are. But yeah, I definitely, you know, every couple weeks or so, think about how I got here. And yeah, it still amazes me like I said, I don't know how I became the baseball biomechanics expert, but here we are.

Chris Gorski  33:15

Has a pandemic been the biggest challenge and building up this work and just continuing things? Or has there been something else that's been a big challenge through these last few years?

Kristen Nicholson 33:28

No, I think the pandemic has probably been then the biggest challenge and then just trying to navigate kind of this dual appointment as what are my clinical, you know, expectations and then what are the kind of baseball biomechanics expectations? But it's been good and I would everybody, you know, advocates for me, and I never kind of feel the pressure of like, a lot of people would say, Well, was it difficult being a young women in male dominated both biomechanics and baseball, you know, they're both male dominated, but, I've never really felt that pressure, the head of orthopedics, the head of Sports Medicine, the head baseball coach, they're all kind of my biggest advocates. And now never really felt the fact that I'm a young female holding me back. So yeah, it's been I've had a lot of support and it's been great.

Chris Gorski  34:32

So what do you do from here? You know, what's, what's kind of next with this? Is it just continuing the work and drilling down on questions or some big jump to something else?

Kristen Nicholson 34:47

No, I think I think that's just continuing on and being able to use it as this player development tool, in addition to kind of the research for a surface pitching evaluation tool, I think is the next step. With hopefully the easing up of the pandemic, you really can start to use it on a weekly basis and answer some of these more pressing questions with more regular captures, and I'm excited to see where it leads, you know, we also have a lot of… hopefully nobody gets hurt. But if they do have a lot of kind of like pre data that we can then maybe start using this as a return to sport tool and really assessing when they're ready to go back and hopefully preventing some of those re injuries by you knowing more granular information about whether or not they're ready to return to full play.

Chris Gorski  35:44

Lastly, I just want to ask what's been the is there a single moment that you can point to as the best thing that you've that that that you've experienced as part of this? In the last couple of

Kristen Nicholson 36:00

I don't know that there's a singular thing this year, especially, I've had a lot of invites to talk it just more like renowned baseball things like a world pitching Congress and the winter meetings, and things like that. So I think having that having those invites kind of really boosts my confidence. And then well, maybe I am the biomechanics expert in pitching and, you know, and I'm good at what I do, there's a little bit of, you know, imposter syndrome, I think still, especially coming from not a baseball background to into this whole baseball world.

Chris Gorski  36:41

I hear a lot of stories like that where people start down a road, and somehow they just get better and better at the thing that they're kind of falling into. And a lot of people just are both amazed and thrilled at how things are working out.

Kristen Nicholson 36:56

Yeah, I would definitely say, I mean, as we mentioned before, just kind of sit back and look, and I'm like how did I how did I get here? I never would have thought that this is where I was would be but you know, MLB teams and scientists and people calling me up every week wanting to know what we're doing and how they can be involved. And yeah, it's a good time. And that's always what you want, right? You want your job and your career to be fun. So I enjoy going in and collecting the data and looking at the numbers and helping the players be the best they can.

Chris Gorski  37:32

Thanks, Kristen. This has been a lot of fun. Thanks for joining me today. Yeah, absolutely. And thanks to everybody, for listening and watching Inside Science conversations. Like and Subscribe, Kristen referred to the episodes with Phil Skiba, who talked to us about training runners and triathletes as well as being a doctor during the pandemic. We have other conversations with more researchers and I hope you'll like those two