Athletic Performance Podcast

Dunks on Demand: The Physics of Flight w/ Dr. Sam Liu

• Ryan Patrick

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In this episode, Coach Ryan Patrick sits down with Dr. Sam Liu, biomechanist, researcher, and movement specialist with the Miami Marlins organization, to break down the true physics behind jumping, dunking, and speed.

They dive into what most coaches misunderstand about impulse, force, and timing — and how understanding the mechanical objective of movement changes everything. From countermovement jumps to approach takeoffs, Sam translates complex biomechanics into simple, actionable concepts every coach and athlete can apply.

If you’ve ever looked at a force plate trace or a highlight dunk and wondered what’s really happening there, this episode is for you.

Chapters
00:00 – Intro: Dunks, data, and the science of flight
04:25 – The simple physics behind jumping higher
08:45 – Why more approach speed isn’t always better
12:10 – Force × Time: What coaches get wrong about impulse
17:00 – The “Mechanical Objectives” framework explained
21:40 – How to use biomechanics without overcomplicating training
28:15 – What elite jumpers really do differently
33:50 – Jumping with vs. without a ball: The overlooked factor
39:10 – Translating jump mechanics to pitching and sprinting
47:15 – Absorbing force vs. managing momentum
52:40 – What Sam’s research is revealing about human performance
57:30 – Final thoughts: curiosity, humility, and the pursuit of better coaching

🔗 Links & Resources
Follow Dr. Sam Liu on Instagram

Dr. Liu’s research publications: 

Connect with Coach Ryan Patrick: 

Key Takeaways

✅ What great jumpers do with force

✅ Mechanical objectives simplify coaching by focusing on outcomes, not aesthetics.

✅ The biggest limiter to jump height 

✅ Force plates are tools → interpretation > data.

✅ The principles that make a better jumper also make a better pitcher or sprinter.

Sam Liu:

But the opposite could be true in the very short term, especially within a session if you're trying to play around with, you know, having an athlete experiment with a range of initial approach velocity. And those two relationships can simultaneously exist because they exist at different scales and contexts.

M-2-peakfast:

Mhm. Mhm. Mhm. Mhm. Mhm. Mhm.

Ryan Patrick:

Sam likes biomechanics. Uh, welcome to the Athletic Performance Podcast.

Sam Liu:

Thank you.

Ryan Patrick:

Yeah, I'm honored to have you here, man. I know you got a busy schedule. We've been trying to work this out for a little bit as you kind of settle into your new job. But, uh, I think for people who are unfamiliar with your work and kind of your just career trajectory up to this point, just give me, gimme a quick backstory and kind of bring us up to speed on you.

Sam Liu:

Well, I actually did my undergraduate degree over in the uk. I did engineering science at Oxford, so, and I did not discover biomechanics as a potential pathway or subject until the third year of my undergraduate. And then I did a biomechanics based masters was more so focusing on modeling how the foot moves as you as different healthy and clinical populations walk and turn. That's actually a huge area of research in the biomechanics field. But I really wanted to do more with sports. So that's where I came over to the States and did my PhD in biomedical engineering at Stevens Institute of Technology. And my dissertation was focusing on understanding the fundamental mechanics behind baseball pitching, as well as fast forward running and jumping and dunking. I sort of came into this degree wanting to learn more about the jump technique, quote unquote, and my professor was like, we have this major league baseball grant research that somebody needs to do. And she's like, do you wanna use it to get started? Because the training, the the, the methods of data analysis are largely similar. And she's, and then I was like, yeah, I'm gonna get a great exposure to, you know, these kind of biomechanical research in the sports setting and eventually develop my own research pathway during my PhD to study more dunking and jumping. So now I have a few publications for each of the topics.

Ryan Patrick:

Yeah, I think for guys on the outside, it's. You don't realize how difficult it is to do performance-based research in a laboratory setting because there's just not a ton of money there.

Sam Liu:

Yeah, no, there's definitely no money for support. I tried to apply to a few research grants to support the efforts and I'm currently over two. I made it to the finalist rounds for both. Didn't quite get the money at the end, but, and also there's other difficulties, like for example, finding a participants. Generally you're limited by the people you have access to. Uhhuh, I have a great community on Instagram with, in terms of dunkers, so that's taken care of a lot of the participants in my studies. But yeah, I, you know, the rest of my participants are really athletes from D three. So that limits, in terms that limits you in, in terms of what you can infer from your results?

Ryan Patrick:

Yeah, for sure. I remember,'cause when I was going through graduate school, um, I went to the university or Colorado State University, so you know, we had a really diverse um. Professorship and, and research interest there. I mean, we had guys that were far, far on the, the spectrum of physiology, you know, growing muscle cells, uh, in the laboratory. And then we had guys on the biomechanics end. And so I kind of found my way towards them'cause I'm like, this is probably the most sport adjacent thing that I could find, but you still have to kind of like almost tie it in with injury stuff. So we were doing, uh, jumping and asymmetries and tying that back, you know, to ACL risk and stuff. But like, that was as close as I could get at the time, so I'm a little jealous. You got to look at dunking. Um, but with that in mind, man, I, I do wanna start at the top and talk about jumping and the, the biomechanic stuff is coming more and more into the private sector guys are getting force plates and so I think just having a fundamental understanding of some of the biomechanical and physiologic principles that really underpin performance is. Huge for a lot of guys. And so let's just start at the top. What, what would you clarify as the determinants of maximizing your vert? And then moreover, what does this actually mean to like the 16-year-old athletes we're training or the coaches who are, are working with them?

Sam Liu:

So I'm gonna tackle this from two perspectives. From the physics perspective, it's actually remarkably simple. Mm-hmm. The projectile equation is pretty much the only equation you need, and it's about maximizing your upward velocity. A takeoff, or, you know, some people will call it takeoff velocity.

Ryan Patrick:

Yep.

Sam Liu:

And in order to maximize that variable, you need to find a movement technique that allows you to have not only an advantageous initial condition or your initial velocity, as well as maximizing your fourth generation during the jump, during the ground contact. And that's basically what people often refer to as vertical impulse. Which is the summation of the force you generate over a duration. So basically to jump as high as you can from a physics perspective, you wanna maximize your vertical impulse and you wanna have a good initial condition, which is the result of your running approach. From a training perspective, it's slightly different. Mm-hmm. Because we have to treat the human as a complex system that sort of develops over time. So for a young athlete, it's really about doing the specific practice enough to develop your own movement patterns. And then you can either experiment with different jump technique modifications for like very specific drills and Q cues. Mm-hmm. Or just practicing a variety of jumps, because I still believe in the variability of practice, which allows you to naturally find your own technique, whichever side you take on that continuum of, you know, specific drills versus variability and constraint based approaches. It's about exposing your body to, you know, generally the better way to jump, generally the better way to generate more force. And then you also need to develop yourself physically to be able to generate high forces at each of the major lower limb joints and build sufficient muscle tissues to stay healthy, to allow you to practice enough over the long term. So that is the, uh, what I think are the major, major terms. The other things are also the icing on top.

Ryan Patrick:

Okay. So you talk about these initial conditions. Most of the assessment assessments that we're using are gonna be the static, you know, hands-on hips jump. What, what information is useful from that and what is really missing when we're looking at an approach jump, which would be more practical to a sports setting?

Sam Liu:

Yeah, I actually think, okay, there are research done. That found some correlation in, you know, counter movement jump performance as against running jump performance. I actually cited that paper quite a lot, but it, I think it only tells you that you are generally a good jumper. Mm-hmm. Because the tasks are very different. The task demands on the body are also very different. Your movement strategies between the tasks are likely very different. And I think the better of a running jumper you are, the more different it's going to look from your counter movement, jump movement patterns and strategies. So I like counter movement jumps for other aspects of performance. For example, how you, it's actually great for monitoring fatigue, especially if you wanna track, you know, the more details of how you jump as opposed to just a jump height itself. Mm-hmm. I think it's fine to track yourself and you track your general ability to handle eccentric forces, even though. That specific task is a little bit too limited. You need to like, play around with different kinds of jumps on the force plate to understand your eccentric capabilities. Mm-hmm. But in terms of like very specific transfer, I, I don't believe there's a lot, a lot of similarities between a running jump and a stationary jump. It's best to just look at how the athlete in front of you is doing a running jump, if you wanna, if you're curious about, you know, running jump performance.

Ryan Patrick:

Yeah. So with that running jump, um, how much does, like the approach velocity compare to these, this ability to handle these centric forces, like modify uh, that performance or do you see, I guess what I mean to ask is do you see that elite jumpers can handle more approach velocity or is there kind of a, a strategy dependent solution that these athletes are, are using that might differ among good jumpers?

Sam Liu:

No, that's a great question actually.'cause this sort of touches on. Some of the approaches that you could do statistically, obviously I'm not gonna go too deep into that. Yeah. But basically there are trends that are generally good on the population level. If you list every boss or athlete ever, let's try to go up for a dunk. Mm-hmm. You're going to see a trend that higher jumping athletes usually come in with more C. Okay. So that is the general trend, and it's a fine baseline guideline to tell, to tell you in which direction you should try to take your training to now for an individual athlete's development. Over time, I think eventually you will end up using more and more approach velocity as your eccentric capabilities, as you mentioned, goes up as your technique becomes better suited to handle more initial approach velocity. Mm-hmm. But in the very short term, having too much approach velocity can exceed your ability to control it. It will actually make you jump lower. So there's this general trend at the population level and over a very long time that sort of mean, that sort of tells you that, you know, more velocity is good. But the opposite could be true in the very short term, especially within a session if you're trying to play around with, you know, having an athlete experiment with a range of initial approach velocity. And those two relationships can simultaneously exist because they exist at different scales and contexts.

Ryan Patrick:

Okay. Uh, I got a follow up question to this. I know I'm already throwing you some curve balls, like one question in, um, so in the, in our setting, you know, when we're watching athletes go into an approach, we're looking at something, say, you know, I want to monitor hip height management, meaning I don't want my athletes to drop their center of mass too quickly, so. With respect to these elite jumpers, one of the things I know that they're doing well is their time to take off is, is pretty quick. You know, they're a, we would, you know, quantify this as explosive force, or they're able to apply these very, very large forces in very short timeframes. Yet on the flip side, we're talking about applying force over time to create this impulse. So my question is, when we're trying to apply this large magnitude of force in very short timeframes, are there certain, uh, biomechanical configurations, like joint angles, things like that, that really help athletes do this? Or do we start to look at some of the, you know, the physiologic characteristics of, you know, their strength, their eccentric, um, force producing capabilities? Are those the things that actually modify this force producing potential?

Sam Liu:

No. Another, another great question actually. I, I'm, I'm loving, I'm loving where these are, these are going, so I think those, I mean, those things are intrinsically intertwined, right? Your physiological capabilities determines how well you're able to join my force against the ground, which is your biomechanics. Mm-hmm. So I actually kind of wanna touch on the impulse and time idea, and I think it's actually a big misconception Okay. In how people apply this impulse definition and impulse relationship. So the way impulse is often communicated by a lot of, uh, coaches is that it's, um, it's force multiplied by time. Mm-hmm. Right? That's generally the definition. But what really determines the your jump height and your takeover velocity, and what really matters in vertical jump is your net impulse. And net impulse in the physics term is the sum of all of your impulse applied, which means it includes your body weight. And your force that you apply against the ground, you wanna apply maximum force that exceeds your body weight, and you wanna do that for as long as possible, but you can't physically do that as long as possible because you can only generate forces that exceed all your own body weight. You know, as you mentioned, from certain joint configurations, right? Mm-hmm. So that's sort of the idea of having a, a lower minimum po minimum vertical position. AK more squatted, more flexed over position at the bottom of the jump. This is where that could be helpful because it gives you more time to generate more force that exceeds your body weight. It's not about generating very low force over a long time, right? That's not a viable strategy. You have to beat your body weight. You have to beat gravity in order for you to jump higher. That's why it's more important to, for your ability, it's more important to train your ability to generate high forces. As opposed to play around other things with time, it's also a lot more modifiable, right? You get stronger in your lower limb joints across a variety of exercises, you're gonna be, have a higher likelihood of being able to generate more force that way.

Ryan Patrick:

No, that makes sense. You know, I work mostly with developing athletes, so getting them stronger is kind of the first stop, right? Like, um, I always say you don't put, you know, you don't put a spoiler on a Prius. Like we want a car with a bigger engine before we start fine tuning and, and modifying that. And I think a lot of coaches have used this analogy, so it's, it's nothing new, but I'm always in the back of my mind considering this constraint of time, right? Because even if I generate high forces, if I'm taking, you know, a 10th of a second longer, which doesn't sound like much, like I might not be at the apex of my jump when I need to snatch that rebound and somebody else might grab that. So how, how flexible is this time variable? When it comes to applying forces above body weight, I mean, what is the range that you're seeing for, you know, these elite jumpers?

Sam Liu:

Um, well sadly I don't have access to elite jumpers data, but just from first principles generally, the shorter the better. Especially if you add in the constraints of time. And there's also a thing where, in example of grabbing a rebound, you might actually trade off between your maximum jump height versus your time to get off the ground. Mm-hmm. There's this flexibility and trade off between, you know, force application and time such that it needs to just satisfy the task demand at hand Right when you grab a rebound. Okay. I'm also making a different argument in basketball'cause I've been a basketball player. If you need to jump that high to grab a rebound, you did not box out well.

Ryan Patrick:

So

Sam Liu:

do your work on the ground. Right. And you might not have to, you might not need all of your maximum jumping capabilities. But the idea is for different tasks in different contexts, you're gonna have different movement strategies. Your body finds the best way to trade off. And to me, from a training perspective, the best way to target those is to target the different ends of the spectrum. Right? This is, I know it's a controversial topic to talk about surfing the curve. Mm-hmm. But just from strictly maximizing your training stimuli in like the different extremes, you wanna go to the extremes. So, you know, if you wanna play, play with speed, jump as fast as you can off the ground in a variety of contexts, and you, you end up being able to do it. And when the game comes and also box out,

Ryan Patrick:

also box out. I think that also box out immediately, soon, as soon as the shot goes up. Oh man, I coach some teams and, and that is like the one thing, I don't know why at the youth level they just, that those eyes just go to the ball and they're just waiting. Um, you kind of already answered this, but. You know, I, I don't know, it was one of the videos I watched of you, our previous podcast, but you talked about your framework centering on the mechanical objectives of any movement or sporting action, which, you know, is just, I think, a great foundational starting point. So for a young athlete, um, should we encourage them to seek, mimic, or emulate, you know, what elite technique looks like? Or is there a better starting point?

Sam Liu:

So I actually used to think you should not try to copy techniques of athletes with very clearly very different physical capabilities than you. Mm-hmm. But now actually I've changed my mind a little bit. Okay. I think for the youth athlete's perspective, there's nothing wrong in trying to mimic and emulate different techniques. If anything, it's a good exposure. We can move slightly differently and just see what it feels like. I think it's actually valuable in terms of your development, just because again, of the movement variability. But I do think it's important not to be fixated on looking that specific way over your performance. It could be a fun thing to experiment with, like who hasn't gone out there and tried a basket of move on the court, you know, after you saw on the NBA. Right. You, you, you all try it. It's a great fun, it's a great way for you to develop body control, but you shouldn't feel dejected if you don't look exactly the same. You can try it, but do not judge your technique through how it looks. You should judge it through how it performs, especially if you're already actively engaging, you know, in the same sport. I think it's actually much more important for coaches and researchers to understand this mechanical objective perspective when it comes to movement technique. And also I can sort of go into, you know, the, the biggest strengths and benefits of viewing movements this way a bit later. Mm-hmm. It's very important to keep in mind the mechanical objectives of the task. If you are studying more sports specific movements, that goes beyond just your regular account movement jumps, et cetera, right?'cause in sports you have the task at hand. You also have things like perception, action, reacting to defenders. You also have environmental factors and other stuff. So yeah, I think it's more important for coaches to know this, to understand this mechanical objective perspective.

Ryan Patrick:

No, I think that's great because I mean, when I was on the come up, I was a big NBA guy and we used to go to this, um, like half court you could rent and we would do low rim dunks trying to basically recreate everything. Vince Carter did, um, on probably like a seven and a half foot ramp, you know, when I was like 10. But, um, you, you, I think the body control piece is way understated. Just, you know, knowing where you are in space. Um, this is kind of more on my end of the spectrum in terms of application, but if we kind of anchor. This mechanical objective first, what is the, what is the progression in the practice or what should it look like for a young athlete?

Sam Liu:

Yes, so I, I think I'll first start by like explaining what this mechanical objective perspective is. Mm-hmm. And this sort of like, I know ties into a later question on the impulse momentum relationship because they're all very closely related. Okay. So the mechanical objectives are basically the minimum requirements in order for you to successfully complete a task. So I'll give a variety of examples so people can have a general idea. Mm-hmm. So in jumping, the minimum requirements for you to complete a task is to generate enough force to defeat gravity and allow you to be airborne. Any technique that allows you to do that technically is a successful technique. Obviously there are some that's more successful than the others, but any technique is successful. Additionally. I'll give you more examples. Yeah. Um, in our lab, we like to study. Besides my exciting research, there's also other less, I'm just kidding. Equally important, but maybe less exciting research such as older adults walking and turning and balance. Mm-hmm. So in their case, their mechanical objective is walking straight, redirecting your body's momentum and orientation, get to your destination without falling. That's their mechanical objective. In a squat example, you wanna squat down with a rate and then generate enough vertical force to stand back up. That is the mechanical objective. And again, in those you wanna maintain balance and not follow. So mechanical objectives tells you, you know, what are the basic requirements for this task to be successfully completed? And it does not care about how you are doing when you explore, when you, when you view things from that perspective. You'll realize there are many different movement techniques that can work for different individuals. So this is when it, so that encompasses people categorizing different athletes. You know, elastic power. Yeah. Why narrow a SA And also it tells you what factors are more important in movements. Because mechanical objectives are usually about how you regulate the body's momentum. Momentum is controlled by forces. It's not controlled by how you look and what positions you hit. It's controlled by what kind of forces you can generate using your, using different positions and using different limb and body configuration. So it's like a very over encompassing framework when it comes to analyzing movements. When it comes to applying it to athletes, it, it tells you what factors are important versus not. For example, in jumping. You wanna frame your jump technique development around things that will help you generate as much force as possible and things that will prevent you from having too much of a downward crash. Right. People talk about hip height management, it's really talking about managing your initial downward velocity, and you can use some of it to generate more force through the stretch filling cycle. Mm-hmm. But it's only up to a certain point. It tells you like which of the diets you can play with. And instead of focusing on, you know, this is where your arm should be at this time point, you can look at the bigger rocks, I think the more important stuff, and it's, it's less specific, but it gives room for the athlete to figure out through experimentation and practice. So I'll stop there.

Ryan Patrick:

Okay. There's a lot to unpack here, so I'm trying to digest all this one. One area that you talked about was, um, you know, these, this categorization of athletes because I think conceptually. It's easy to decide what interventions might be relevant to improve, you know, these mechanical requirements or minimum necessary, um, capabilities that we need to get right. Defeating gravity. So you mentioned like the elastic versus the, um, muscular athletes. Very common one that we understand. People that are more into like the, um, I would say nerdy biomechanics might talk about these wide versus narrow ISA and that can go down a deep, deep rabbit hole. But my question to you, with respect to this mechanical perspective and the objectives required, how much of this categorization that we're using is actually useful shorthand for coaches and how much is just kind of maybe oversimplifying, um, complex mechanics?

Sam Liu:

Um, I, the thing is there, I don't think there's enough data for me to say if there are oversimplifying it or overcomplicating it. Because there just has not been, I mean, any research to back any of these up. Okay. Um, I actually had a lot stronger takes about whether you should use these categorizations at all, but I've sort of grown more, um, peaceful over the years. I think I, I acknowledge that it is a useful way for coaches to respect individual differences at the minimum. Yeah. It, it's a way for people to move on from treating everybody the same way, giving everybody the same prescription. It's a useful tool to help you understand, you know, different people move differently because the mechanical objectives of the task allows you to move in a variety of ways. Okay. It's actually also a general trend in a lot of research and practical settings where we are moving away from like the, the general population or what we call group level, right. Where we're treating everybody as like, you know, a everybody as one data point that moves the same way. We're going into more looking at individual trends. I do not think there's enough evidence to support the rationale, the explanations behind, you know, here's why a muscular or elastic jumper should move this way, should train that way. I don't agree with the rationale, and I just don't think they're strong enough evidence to support them. You can use it as a tool to say you move differently, but I don't necessarily think you can fully justify or treating them, treating their training completely differently. You should still examine how they respond to the training stimulus that you apply, and obviously pick the tool that's best for the job. Right. If, if a categorization of a muscular versus elastic helps you make better exercise mm-hmm. Just, uh, descriptions, sorry, prescriptions, then, you know, feel free to use it. I have nothing against it. I just don't believe in the way people explain it because it doesn't make too much sense for me, and also I don't, I don't see strong enough evidence to support those rationales, but I think that's also for the most nerdy people, replication. You can do the right thing for the wrong reasons, and that's okay.

Ryan Patrick:

Yeah. Which, I mean, sometimes we, we fall into dumb luck. Whe when we're looking at, uh, jumps, speaking of like an individual level, so I know some of the, in your research when you're doing the, the running jumps, how much variability was there on an individual level between these jumps? So they did, you know, four or five jumps, I can't remember exactly how many you were able to calculate, but what is that, what does that look like? You know, because it's easy to look at the, the tables and the charts and to get these averages either at a population level or at an individual level, but within a specific series of jumps. Like what kind of variants are we seeing?

Sam Liu:

I'm actually seeing like, because these jumps are very well practiced. Mm-hmm. So the way actually we would describe this in research is that we are researching movements that are. Well-practiced goal-oriented tasks. Okay. In that sense, people perform it in a very specific and reliable way. So within the same person across repetitions, there's actually not that much variability because they've done these kind of jumps enough times. I'm also seeing some of, I'm seeing a re, a pretty good amount of consistency across individuals in how they generate forces against the ground. Like I call it the impulse generation strategies, which is like how much low, how much force generation you distribute between your plant leg or the block leg, or you know, as I call it, my paper. Your first and the second leg in terms of what, what context? The ground first versus second. So in that sense, there's actually a quite, the sample is what we call quite homogeneous. Mm-hmm. Everybody behaving fairly similarly when they're generating vertical forces. Now when it comes to generating horizontal forces or breaking against your four momentum. We notice a a lot more participant variation and that's because there you can break more with your plant leg, you can break more with your block leg. As long as you generate enough more forces, you're fine. The reason we are seeing more homogeneity in the vertical force is because as you contact the ground with your, with your plant leg or the first leg, you're already generating a lot of vertical forces already. So it's just the nature of when you do this one, two sequence, your first leg is just gonna generate more vertical force because it's being with the ground longer. Okay, so those are like some quirks of, yes, there are individual differences, but I don't think it matters as much. It's about whether you can fulfill the task at hand, which is controlling your horizontal velocity. As long as that's done, we're good to go. Okay.

Ryan Patrick:

Um, kind of on this note, obviously with a one leg jumper, we're not gonna have plant block leg. Mm-hmm. So can you just riff some of the differences in strategy or maybe advantages, disadvantages, when it comes to, you know, using one verse two legs?

Sam Liu:

From what I'm seeing from research, I know there's been actually very, there, there's been a few papers, like two that compares one foot and two foot jumps. But generally the sense is one foot jumping is a lot more restrictive in the kind of movement strategies you could use in two foot. If you consider, you know, spending longer time versus shorter time, you have like almost four combinations, right? You can have either legs spending longer or shorter times with different movement strategies. But for one leg, one foot jumping, it's a lot more constrained. It places a lot higher of a demand on your lower limb joints. It's actually quite difficult to maintain balance as you run in with greater and greater. So it's just, it's, it is straight up a tougher way of jumping. Even though, you know, for some people they say, oh, I can never figure out two foot jumping. Well, that's because you don't practice it enough. But I think at the highest level, one foot jumping, it's just more mechanically difficult. I think there's also just less movement variability in one foot jumping, especially successful one foot jumpers compared to two foot jumpers. You see a lot more technique variation when it comes to two foot jumping.

Ryan Patrick:

Yeah. Have you tested like performance, like outcome one verse two?

Sam Liu:

It's actually very difficult to do that research because if you're really good at one foot jumping, you're going to just jump a lot more of your one compared to of two, right?

Ryan Patrick:

Yeah.

Sam Liu:

You could have someone that theoretically could hit a higher two foot jumping, but they just haven't practiced it enough at the time of data collection. So it's, it's a very difficult study to run theoretically. From a first principles perspective, I think it's. You are likely to jump higher with the absolute height of two feet just because you can distribute the forces across both legs. Mm-hmm. And then you won't get as close to the maximum tolerable, you know, tissue forces compared to one foot where you do get quite close in how much your tissues, lower limit tissues can tolerate those forces. In two, you almost, you can distribute the loads and therefore allows to generate greater forces. Theoretically. Yeah. Than you could just only have one leg. It's like the, you know, you have both legs on the ground to both generate forces. So,

Ryan Patrick:

yeah, just kind of thinking out loud here, but it would seem to me that if I'm jumping off one leg, I'm not gonna get the same level of change in my center of mass, you know, at its at minimal, at its minimum height. Like so does that leg, is it just a more rigid strut that they're kind of. Using that momentum to some degree. I mean, it just seems like you wouldn't have the ability to, to almost like, I always think of it like going up a halfpipe, right? We've got all this momentum coming in and we wanna redirect as vertical as possible, but with one leg that is really insanely difficult to do. So it, I just feel like they're passing over with, you know, straighter joint angles. Am I, am I wrong here?

Sam Liu:

No, you're actually, no, that's actually a very, very, very great point and one huge distinguishing factor between one foot and two foot and two foot. You see a lot more of, uh, the descent of your central mass. Mm-hmm. When one foot that's actually discouraged and there is like one paper done by Jesus Ena, who is like one of the OG biomechanics researchers in the HighJump space. He basically stated that you do not want too much of a vertical syndrome, mass descent after ground contact. But as you mentioned before, having this bigger vertical range of motion for your body is generally advantageous for jump heights. And high jumpers achieve that through a combination of a backward lean as well as leaning, running a curve. So it allows to, so you, you're so, you're able to lean backwards and lean into the curve. And that's one way they're getting some center mass descent as they go into the plant, but they definitely cannot afford to, you know, have too much lower limb joint flexions just because of the demands on the lower limb.

Ryan Patrick:

Yeah. So, yeah, that's a great, you're not gonna see a basketball guy lean back like that though.

Sam Liu:

Absolutely not. And also, you don't need to jump that high of one compared to like, you know, the elite world class high jumpers. I actually think the high jump rules that only allow you to jump off one foot is, I think it's dumb. I don't care about traditions. I, I think if you define the task, I want you to define the as simply as possible. I don't want you to specify anything about technique. Just define the task and let the athletes figure out what's the best. Way to fulfill the task, you know, jump over the bar. Done. That's it. As hard as possible. Don't care how you do it, just do it.

Ryan Patrick:

I

Sam Liu:

think that's great.

Ryan Patrick:

You

Sam Liu:

know, we can only dream

Ryan Patrick:

one day. We'll ha we'll start our own event. Um, okay, other constraints. So one verse two ball in hand. How does that modify the jump? I've heard you talk before, like obviously if we're gonna, we're gonna post our eyes, somebody, we've gotta reach our apex before the rim, so we're jumping from a little bit further away. We're still gonna have some forward momentum in the jump versus just jumping up and reaching a target. But what do we know about how this is actually modifying the strategy of jumping?

Sam Liu:

No, I, I actually, I, I love talking about this topic. It was so difficult to research this, actually.

Ryan Patrick:

Oh, I'm sure. I can't even imagine. I mean, how do you control for that

Sam Liu:

before? Yeah, before my, before my research, like I have like one paper, it's like the most complicated paper I've ever written. That was like the only one that compares jumping with, without a ball in a running jump setting. Mm-hmm. In like 21 people. So basically there were a huge variety of individual differences as expected, because different people have different skill levels and how they jump with and without a ball. The way I did the research was I, you know, I have them come in, obviously do all your warmups, you attach your sensors, and then just randomize the order of jumping with and without a ball. So, you know, they might have like three trials without a ball, two trials with the ball, et cetera, et cetera, until they have like at least three each with good enough data that I could analyze later on. So that's sort of how you can control it. You just randomize the order. And you sort of assume that yes, there's gonna be some crossover in the way they move, but because the tasks are different, you're just trying to observe movement differences between the tasks. There are certain statistical things you can do to control for that. You know, interdependency, we call it like depend trials where they somewhat relate to each other. Yeah. But are also different enough. So basically all the individuals perceive that jumping with a ball is a more demanding task if you're a basketball player, you know that's true. But there are some people that generates less force when they jump with a ball. Okay. There are some that modifies how they run in, which means they have more of a downward cinema as crash. There are some people that do not modify either conditions and they actually jump the same. So basically. You do not wanna, but, okay. So in terms of like all the different things that could be changed, the most common is people just generate the less or so forth it could be because their plant legs, forces lower, or the block, like forces over lower, but we don't. But beyond that, we cannot really say what the causes are. Okay. But we could say, you know, as you jump with a ball, maybe you need to put more active attention into really putting the force into the ground or driving up with your arms. Right? We might need to be more intentional in our specific practice with a ball because there's this additional cognitive demand of holding the ball. Okay. We also don't want to change our running approach too, too much, but then jumps with and without a ball. I know when people dribble with a basketball, their posture changes compared to how they would just run normally. So being more mindful of that is also important. And the conclusion of that paper is really, you know, these tasks are different enough even in these groups of skilled basketball players. So we should probably practice dunking and jumping with a ball specifically in addition to running and jumping without a ball. And if your goal is to be a great basketball player, honestly you should just practice majority with the ball, right? You can do an off lob where it also allows you to train a, a different aspect of a dunking specific skill, which is also good because it teaches you timing, teaches you how to look up and find a target, and actually is a great tool for teaching. You better touch as your hand interacts with the ball during the air. So yes, they're very different I think.

Ryan Patrick:

Okay. Um, this to me, highlights a bigger issue when looking at jumping. So we do this on the force place as well, right? Counter movement, jump with the arms versus without. So when I have a ball in hand, obviously the contribution of my arms to the jump is going to change. Now, historically, I think what we've been told is when you do an arm swing, right, you're getting more downward velocity, which you have to overcome, buys you a little more time to push against the ground. So we can have that force, um, above body weight increase. Our propulsive net impulse is, I guess before we even talk about specific with the ball, but what is the role of the arms in jumping? Are they, is that, is that classical interpretation that I talked about still accurate? And I guess, does the ball really modify our ability to use that? Is that why potentially that, uh, vertical ground reaction force goes down? I know we're getting into the weeds here. I'm sorry. Oh, no. I

Sam Liu:

love it. I've dug, I've dug in, I've literally spent like years looking into papers that come, it's actually one of strength and condition research's favorites. Comparisons. Yeah. It's the classic counter movement jump with arms Without Arms, and it's actually one of the driving forces behind like my hypothesis for the, uh, vulnerable paper. You know, obviously in vulnerable it's a suppressed arm swing, as I call it. Mm-hmm. Versus complete elimination of the arm swing. So there's this one paper in 2004 by Adrian Lees, who's from the uk. He does a lot of track and field and jumping base research, and the paper basically aims to causally, um, understand why jumping with arm swing helps you to jump higher. So there's a few rationales that were stated in that 2004 paper. Number one, as you mentioned, is the vertical range of the center mass as your arms is, you know, straight at the very bottom and overhead at the very top. It gives your whole body center mass, more vertical range motion to move through, and therefore that's what you're talking about with the time, right? You have more time to do post of impulse and that is entirely accurate. But then that paper tries to get into how the arms is trying to, the arms momentum is exerting a force onto the shoulder girdle, which accelerates your Trump upwards? I don't know. I'm not sure about that. Okay. But it, yeah, it's a very confusing aspect. And obviously if you have different papers with different groups of athletes doing the same test, you're gonna have different explanations for, you know, oh, is it the average force that's modified? Oh, is the duration of proposed impulse that's modified? Both occurred, but it seems like it's the proposed impulse generation duration, the time piece. In like three of three of the four papers. That's like the only factor that's different. Hmm. In one paper that looked at it in the volleyball players, it found that both average force and the proposed of impulse duration were changed. So, you know, then we sort, we can sort of assume, you know, both can be modified. We don't exactly know how in the lower limb joints, I think you need to probably, I don't know, measure, uh, lower limb muscle activation patterns that you have to model for the, you know, the lower limb joint forces and moments. But again, you know, this is a point where I don't think understanding the full mechanism matters as much as just understanding what is the broad biomechanical differences and, you know, how it, how it, how it impacts the way we use CM js as a testing tool.

Ryan Patrick:

Okay. I think there's value in that. So. I guess a follow up question is, you kind of started to, to go down this, so I just wanna kind of nudge it a little bit more. Even though you said you're more a man of peace now, but um mm-hmm. Where do you see coaches kind of misapply physics in the weight room or on the court or jump training and, you know, how does this kind of impulse momentum framework keep us honest?

Sam Liu:

Yeah. Well there's a few things I think people often oversimplify, which, okay, it's a paradoxical statement.'cause I think the physics, physics that govern jumping is quite simple. Mm-hmm. But people tend to oversimplify the i impulse momentum relationship, like the example I gave with time. Right? Yeah. People sometimes say, oh, you wanna maximize time, you wanna minimize time, et cetera. And then that's a seemingly paradoxical statement. It's the cost of full contact. It's missing where it's time. When you're beating gravity. Yeah. So those are really the, the full context being missing to me is when it's most being misapplied. But other than that, I think people generally actually just tend to stay away from these mechanics concepts. Mm-hmm. I know only a few groups of people that really tries to get into the impulse stuff. Yeah. Where they're saying, oh, you need to maximize the duration of breaking impulse, for example. Where, but then they do not really define what, what is breaking impulse? Are you breaking the vertical direction or breaking the horizontal direction during a two for running jump? You are doing horizontal bra throughout the entirety of the jump, but you're only doing vertical breaking during the initial sensor mass phase. Right. Really not fully understanding the concepts and fully communicating it when they are trying to make posts about it. That's to me, when, when I will make a response post,'cause I'm like. It takes an extra five seconds to lay out the full context. Right. But I think it's not really you trying to actively deceive it might be a understanding problem, which is totally okay because, you know, instead of earning money, I was spending five years doing a PhD. So sort of how it is.

Ryan Patrick:

Well, I I think part of it too is, you know, we talked about the, the commercially available force plates, they're, they're not mm-hmm. Looking at the horizontal components. Yes. Which are huge. Especially if we're talking about an approach jump like this. We've only got the vertical vector.

Sam Liu:

Yes. No, that's actually, that's a great thing.'cause when I actually, I went to a conference about a month ago where I met with my professor's professor, my grand professor, and essentially she told me this, she's like, the directions of motion, the directions of force application, that's what skill is. True skill and the movement is how the athlete's able to generate forces in specific directions at specific times relative to their body configuration. That's also something that the Alta strength coaches are talking about. It's the direction, the direction of forces really matter if you wanna understand skill movements and you lose that if you only use the uni axial force plate, or those that only measure forces in the vertical direction. So those can only tell you broad general movement strategies rather than give you any insight into Han Athlete might move in a skilled setting.

Ryan Patrick:

Yeah, I almost see the inverse in sprinting since you mentioned Altus, where everyone's focused on the horizontal vector. And you know, we have to concede that a lot of the, the DRF calculations that we're using outside of like a 10 80, which I think of as almost like a horizontal force plate are, are estimated. And so we get so caught up on this horizontal, um, force application that we miss how essential having like a minimum necessary vertical component is in sprinting. And I know this is kind of going down a different rabbit hole, but, um, have you seen that problem? I don't know how much you're actually looking at sprinting.

Sam Liu:

To me that's, uh, more of a Lance Brooks. Lance Brooks now a Bridgewater University. He does a lot more of the spring team stuff. And I have Lance on

Ryan Patrick:

before. He did a great podcast here.

Sam Liu:

Yeah. Um, you know, he shouted me out on another podcast. I'm gonna shout him out here. He not, he does a lot more with the forces, but basically. Yes, you do need enough vertical force to again, beat gravity to make sure you can stay off the ground and running. And you know, I, I'm sure he probably went into the whole breaking force debate. Mm-hmm. So, to me that's also a, a sign or really a symptom of not really understanding the action of the body versus directions of the forces breaking impulse. When we are describing it in a, in a research and physics sense, we're describing a direction breaking meaning it goes against your current direction of motion. Mm-hmm. But we are obviously, no one's gonna coach you to actively break as a action. Right. When we are sprinting, nobody's thinking, oh, I got a break, I got a break. Your body just does whatever is necessary to fulfill the task and ends up generating forces in a direction that aligns with the brake. And you needed to do that to, so, and you need to do that during the stride where you have initial contact. Your foot is slightly in front of your center mass. You're gonna generate some breaking force. And then you're gonna generate some proposal force. When you're at top speed, those impulses equal, you stay at the same speed. You don't have any net horizontal acceleration. So I kind of rambled a bit, but basically I wanted to highlight, you know, there's differences between directions and the way we define and describe directions. Breaking proposal versus the actions where, you know, action is something that a athlete and coaches think about. Mm-hmm. But, you know, directions is just what is directions relative to the movement of interest.

Ryan Patrick:

Yeah. So on that note, I, I want to go with the topic, you know, the idea of force absorption. There are a handful of people who I think are kind of poo-pooing on this idea. Like, you can't absorb force, you can only produce force. Um, but we have these breaking components. So can you riff on that a little bit to maybe clarify the understanding that people don't, you know, aren't getting into these really rigid camps and how they're looking at things.

Sam Liu:

I even, I forgot about force absorption. That should, that should probably be the answer for one of my earlier questions. But I think the field, the field, uh, swung back and forth a few ways. Um, I can see where they're coming from. I'll say this, I can see where they're coming from. Um, and technically it is, it is incorrect. But, and also I did offer, in like one of my earlier posts way back, I did offer, I think, you know, um, con regulating momentum, breaking your body's velocity, like deceleration, that could probably be a better term than force absorption. Mm-hmm. You are really absorbing your energy, absorbing and redirecting energy. You know, some people say, oh, convert to the heat, et cetera, et cetera. Um, hidden sound, really, when you land, um, you, you make a sound. So, so that's, I don't know. I, I sort of move past the point of saying, oh, there's no force absorption. I see where you're coming from. As long as you don't, you know, go ahead and teach and charge people for, you know, for a membership or a seminar and then go talking about force absorption. It's a fine concept to explain to athletes as long as you supplement with, you know, you are breaking against your current direction of travel. Yeah. You're breaking against your momentum. You are slowing down your momentum. Right. Slowing down momentum, I think is a easy enough concept for people to get behind. You wanna slow down momentum in a gentle way, absorb force softly. Mm-hmm. You wanna slow your momentum in an aggressive way, absorb force sharply. Mm-hmm. You can sort of like swap out these sort of phrases if you think it's a big enough problem when you use the phrase force absorption and obviously, you know, some, some ISTs are gonna like scoff at the idea. Right now I'm sort of more peaceful about it. Um, it's technically incorrect, but also. As long as you don't try to use it as a educational phrase, I don't care what you do with it.

Ryan Patrick:

Yeah. Um, I have a clarifying question, just'cause I'm gonna start your villain arc now. Um, you know, we talk about the stretch shortening cycle as the storage and restitution of elastic energy, and you said maybe energy is an appropriate term while force absorption is not. So could you kind of, I know we're like really trying to sift, um, and get into nuance here, but I I'd love for you to just expand on that a little bit.

Sam Liu:

Yeah. Let me, I, I'll start with the foresight. I'm a lot more comfortable with the foresight. I might have misspoken with the energy side, I don't know. But on the foresight, the reason that you cannot really have force absorption is because forces are, are a quantity that's always transmitted and never quite gets lost. Okay. For example, if a push against a surface, the force transmits from your, you know, the pushing side onto the surface itself. Even if you land, the totality of the forces are still being exerted. Yep. Right. Even if you land softly, you still need to generate enough force to control your body's momentum. That's why I think talk, when you talk about forces, you always have to tie it with momentum because your momentum dictates how much force you need to generate. Mm-hmm. If you wanna absorb force in a gentle way, where you do that is you, you, you have the same amount of vin initial momentum and you're just increasing the time. Mm-hmm. Thereby reducing the demand of force generation. Right. Force absorption is just really talking about a greater phenomena that includes fourth generation at different magnitudes and fourth, fourth generation durations at different length. Okay. Energy absorption. I know like people say, oh, energy is not neither destroyed or created. Right. In a closed system in, in most of human movements. When I say you gen, you sort of, you absorb energy. It's because you come in with a certain amount of kinetic energy and that energy just sort of goes away in the kinetic domain. You no longer have any kinetic energy left after your limb. So that energy has to go somewhere. And it generally, you know, goes into your body, it goes into your muscles and your muscles sort of takes on. But those kinetic energy by, you know, doing work against it by generating forces against your coming energy. So it might not be accurate to say it's absorbed, you know, maybe it's converted. Some of it's converted the heat. Mm-hmm. Some of it's converted to elastic energy is in your lower limb. Yeah. As you stretch your ligaments and your muscles, some of it's to the sound, you know, nobody's gonna ever do research on how much is which.

Ryan Patrick:

Yeah.

Sam Liu:

cause it's, you know, what's the point? But that's the general idea. It might not have been the most accurate, but that's the general idea.

Ryan Patrick:

No, I think that's, I think that's a really good clarifying point just to understand, you know, what we're talking about in a coherent and consistent way. Um, man, we,

Sam Liu:

we've been going almost an hour actually there's, go ahead. Sorry. There's something I do wanna add to that. Yes. That's also why you should look at things from a momentum or mechanical based perspective because it's really, you are solving the problem of handling momentum. Mm-hmm. And when you view it from that lens, you're like, okay, I have, we have these initial momentum that we wanna deal with. We wanna, we wanna solve it in terms of we have this downward speed, we don't want that anymore. With that framing, you think about, okay, so what are the requirements for us to solve the problem? And it's to generate sufficient forces over sufficient time. So that's sort of tells you, you know, that's, that's the requirement of fourth generation from the perspective of momentum. If you start with momentum, things tend to make a bit more sense because momentum is what defines the task.

Ryan Patrick:

Yeah, no, I think that's phenomenal. And, and kind of on that note, you know, we've, I was gonna say, we've been going almost an hour and I do want to touch on baseball because you are a marlin now and you've got some research in this topic. Um, so with kind of this impulse generation, I think of, you know, the, the task of a basketball player is to overcome gravity so we can get airborne. The momentum and the force that we're trying to generate for say a pitcher is we're trying to put this into an object that is then gonna become a projectile. So, um, I guess when we're looking at, you know, the differences that require this whole body impulse generation between, you know, different legs, especially with two foot jumping, what are some of the similarities, um, in how these athletes create and redirect momentum?

Sam Liu:

No, that's, that's so fun. Um, that's actually one of the things my, uh, dissertation committee asked me to add into my defense, which is a comparison of these two movements that I've done research for. So I sort of briefly describe, you know, the context of momentum of first generation requirements in these two movements, and then sort of go from there. Mm-hmm. So in bass we jumping, you mentioned beating gravity. That's just one of the requirements in a running jump. You also have to read, you have to regulate your body's initial forward velocity. So Okay. Regulate your body's forward momentum. In addition to creating vertical momentum and obviously maintain balance, like balance maintenance is always an implicit requirements in the momentum domain. In baseball pitching, what's interesting is like the task objective, if it's, if you wanna maximize ball speed is to maximize ball momentum. So you do whatever movement pattern you need that helps you maximize ball momentum. And the strategies, you know, within the constraint of the rules of baseball.'cause you obviously, you can't run around with a baseball in your hand straight, like a, like a sen gun in Azo.

Ryan Patrick:

Yeah.

Sam Liu:

The strategy within the cons, constraints of the sport is, you know, people generate initial forward momentum of the body with a back leg. They break against that momentum aggressively with the front leg and then they let their body rotate over it. Mm-hmm. So we can say it's beneficial but not required. It's beneficial for athletes to generate whole body linear momentum, turn into whole body angular momentum, and then transfer that momentum through the throwing hand into the ball. So in that sense, these are very different tasks with very different momentum regulation strategies by design. But the similarities between both is generally when you put your feet behind you, you're gonna generate forward impulse or forward force. When you put your feet in front of you, you're gonna generate backward force and backward wind. So where that's similar between a running jump and a pitch is that if you wanna generate forces to regulate or counter against your horizontal momentum, you need to make sure your limbs are in front of you. This is what happens when people talk about their, the plant angle. When it comes to talking about jump technique, you wanna make sure your legs are sufficiently in front of your body center mass. That allows you to generate a lot of backward forces. Mm-hmm. Another example of the, the consistency between your limb, positioning around your body and force generation is in change of direction. If you wanna move side to side very effectively, you wanna make sure your legs are positioned outside, far outside of your body's space, for lack of a better term. You wanna position it laterally enough that allows you to generate lateral forces. Because forces generally go through your limb as your hips, knees, and ankle exert against the ground. So by positioning your limbs in advantageous positions, you can generate the required forces easier. So those are the similarities I see from a mechanics perspective. But they are supposed to be very different

Ryan Patrick:

supposedly. Um, so when it comes to, you know, strategy, especially in pitching, there's uh, quite a bit of variance in like tall, slender pitchers. You know, you're six foot three plus, and then some of these shorter guys. What are some of the, uh, strategic differences in the way that they're, they're trans, you know, creating this angular momentum through the ball.

Sam Liu:

So there are some general things, but I do not, I don't wanna like, you know, move away from fitting everybody into one mode versus fitting everybody into two modes.'cause to me, right. You know, that's just. So that, that's slightly better, but not that much better. Yeah. Um, generally if you consider, again, it's about maximizing the ball's, linear momentum through space. Since the ball has a fixed mass, it's about maximizing the ball's, linear velocity through space. A taller, longer athlete. To achieve that greater linear velocity, you can, you don't have to rotate as fast because you have a longer lever to rotate through. So it could mean that, you know, for shorter athletes, you need to generate greater rotation of velocities and that's what's gonna help you reach higher and linear velocity for your hand and your ball. But for longer athletes, you need to, you could afford to rotate a little bit less fast, as long as you make sure the linear velocity at the very end. Okay. Your hand mm-hmm. Is high enough, but there, I think it's too early to bucket people. Because even as what we see from major league level baseball data, you're gonna have people with very different looking physiques. Yeah. Throwing all kinds of different ways, different technique variables are going to click for different athletes. And there's, it's, it's very different between individuals. Even though, you know, a coach without any better would be like, oh yeah, that's a, you know, tall and four, that's a dip and drive. But, you know, the dip and drive can rely more on the rotational components of the trunk to throw fast. But, but you, you never know until really dig into the data and really try to find those relationships. Otherwise, I think you are just sort of like, you are just reaching for something in the muddy water and seeing, seeing what could work. And you, you have, I'm gonna have lower confidence in that actually being the case.

Ryan Patrick:

Okay, man, that was this, this was a lot. So I'm gonna hit you with a few, uh, kind of outro questions that can be pretty short, or you can expand on'em a little bit more if you want. But, um, kind of shifting gears back to basketball, man. Um, who is your favorite dunker, or what is the, uh, the dunk contest that everybody needs? A YouTube.

Sam Liu:

Oh, I'm, I'm very basic with that. I, I loved, to me growing up, because I, I'm a, I'm a bit younger. Yeah. So I loved the Zach Levine. Um, Aaron Gordon. I think it's, I don't remember which year it was, 2016 or something like that.

Ryan Patrick:

Okay.

Sam Liu:

The Aaron Gordon's first dunk contest, where he did, he did the under both legs. Zach Levine, just spam behind between the legs for most of'em. I, that's, that's my favorite. Okay. Um, my favorite dunker, gosh, I, I don't really have any, I enjoy all the athletes that can dunk. Um, in like the dunk community, I do have a tendency to gravitate, gravitate towards more power dunkers. Okay. People that take longer to get off the ground, because that's just the kind of athlete I am.

Ryan Patrick:

Okay.

Sam Liu:

I love jumps by Chi. I love, uh, Calvin Dunks. Shout out to those Calvin Aron. Um, they, they take their time. They take their sweet time getting off the ground and that's, you know, that's the way I like to, uh, go in high jump.

Ryan Patrick:

How's your, how's your dunk game?

Sam Liu:

Oh, not great. Not great. Um, currently I, my buddy signed me up for more men's league that sort of goes in through the end of the year and after that, you know, I'm gonna have like some potential career changes at that point. He's also gonna do his postdoc up in Cornell, so, you know, I'm gonna play more basketball in the short run. I've been dunking a lot more outside with those, a few dunking friends at Brooklyn Bridge Park, they have a low rim at nine six. Yeah. I was chasing in the windmill on at nine, six, all summer. Um, I got really, really close a few times, but, you know, uh, with all the travel, with the Marlin's job and this basketball thing, the, the dunk dream will take a backseat for a bit. I will still do a, I'll get a few jumps in after the warmup for the game, you know, just to steal micro, micro dose, like the micro list of micro doses. But yeah, I will take a backseat in the foreseeable future, but, you know, that's okay because I'm not, I'm in no rush to, you know, chase anything's, that's another nice part. You can, you know, life happens and you just take whatever you enjoy doing the most in the moment.

Ryan Patrick:

Yeah. Yeah. So, uh, what, what projects are in the pipeline? What are you excited for that that's coming up?

Sam Liu:

Yeah, no, I actually have something to do something, some work done with the MBA dunk score, where it's something they push out in the past year that reports a bunch of different biomechanical variables relating to jumping. I wanna do a paper with that, just kind of being procrastinating with the new job at the job search after my defense. I do wanna get that pushed out. You know, I have a few collaborators that even got me some NBA combined data, so we can look at, you know, your combined testing jump versus your in-game jump. And that could be pretty cool with these kind of data, you're never gonna be limited by sample size, so you, I have like 10,000 dunks of data that we could run different correlations analysis with. So that, I'm really excited about that. But yeah, nothing too major. Um, we have a few things in the docket that will, that, you know, hopefully I'll announce like, you know, in a, in a few months, maybe the start of the new year,

Ryan Patrick:

but yeah. Yep. Well man, you get to enjoy a little time.'cause I mean, I've done a master's defense and it was full throttle, so I can't even imagine what it was like doing a PhD and having the career change. So you probably deserve a little downtime.

Sam Liu:

I actually have my food defense. It's, uh, I, you know, my, my mindset then was like, I'm only gonna do this once. I'm just gonna take my time. I was, had, I was, I was actually sick. So I had to like, take a drink of water like every five minutes, but that's all on my YouTube, so I guess, you know, I can just plug my stuff here and you know, you don't, so I'm just gonna plug it. Um, I, my Instagram, Sam likes biomechanics PhD. I did a PhD at the end after my defense. I think I, I, I thought about not doing it, but I think it's, it's a funny bit. The name just sort of gets longer as I get more things. Yeah, that would be pretty hilarious. I also have a YouTube where I put the longer form content explanations on. So that's again, same like bio mechanics.

Ryan Patrick:

Yep.

Sam Liu:

And those are the two of my most, uh, used social media.

Ryan Patrick:

Okay. I'll make sure I link those. I did watch a good chunk of your defense, so. Mm-hmm. Um, I gotta finish it and I plan to, so I'll make sure I link that. I'll make sure I link, uh, your Instagram, which seems to be the best place to find you.

Sam Liu:

Correct? Yeah. I honestly don't feel bad, like that thing one hour, 44 minutes. Like even my partner, she's not gonna watch the whole, she's not gonna watch the whole thing. So yeah, it's a whole movie.

Ryan Patrick:

It's all right. Uh, just little bits and pieces. Well, man, um, I'm gonna let you go here. I wanna be respectful of your time. I appreciate you coming on. This was an awesome conversation. I know we, we kind of went in a lot of different directions and got in the weeds, but, uh, I think for anybody interested in jumping and just understanding, you know, all the science behind it, I thought this was, was killer, man, you really kicked ass. So appreciate your, your knowledge and insight and we'll, uh, definitely keep tabs on you so we can just kind of find what's new with your research.

Sam Liu:

Thank you very much.