The Biggest Problem with Speed Training w/ Dr. Lance Brooks

When we're looking at the understanding of speed and power, what do you think are like some of the biggest laws that you see in the sports performance realm and as far as power would be interpreted? So we'll talk about power in the context of sprinting specifically since it is a scalar and has no direction by definition, it inherently ignores multiple movement and multiple axes. So there's no direction, so we're talking about horizontal power. We're ignoring the vertical force demands that are ever present and ultimately the most important mechanical demand in sprinting. Take Juan Barclay is a squadier runner, but is it that much different from the Asafo Pal Model? Without being too harsh, I don't think that there's basically any value in this model of squaddy running where putting our limbs in joint angles where suddenly you're not able to cover as much distance with each stride. So you're putting yourself in a position where you're much less affected from stride stride. Now you're decreasing the effective mechanical advantage of the muscle acting on the limbs, the tension demand that the muscles are having to produce in order to meet the same force requirements on the ground, but you're not able to do that from that posture. Any specific tests like a flying ten, like a 40, like a shuttle, like anything along those lines that you like to do, if we're talking about straight speed or even ability to cut, these are the best tests that we can see. The cop out answer that everyone gives or everyone should give, in my opinion, is it just depends. It depends on. We're going to go into the biggest problem of speed training with Dr. Lance Brooks, and we're going to start right now. So we were privileged enough to sit down with Dr. Lance Brooks. He's the owner of Brooks Performance Methods. Dr. Lance Brooks gives us a whole bunch of different aspects around what is going on that is wrong in the speed world. And not only does he tell us what is wrong with the speed world and how we look at speed and how we analyze and measure it, but he also gives us a specific resolution. He provides specific examples and how you can apply that in your training today. I took seven pages of notes for this specific podcast, so sit down, get your pen, get your paper, and start being prepared. Now let's break down speed training with Dr. Lance Brooks. Okay, Lance, when we're looking at the understanding of speed and power, what do you think are some of the biggest flaws that you see in the sports performance realm in relation to understanding speed, understanding movement, and as far as power would be interpreted. So it's a good question. So when we think about power and the way that it's used colloquially in the field, it's really used synonymously with things like explosiveness. When we're trying to talk about those sort of dynamic qualities that an athlete or a sprinter would have, you think, oh, you want to be powerful, you want to be explosive, you want to maximize power, those kind of things. But power has a very specific mechanical interpretation in science. And if we're talking about the field advancing and taking more seriously as a discipline in science, sports science, then semantics do matter. So when we talk about power specifically, it's the rate of doing work. It's a scalar quantity. So it's not a vector. So in other words, it doesn't, it doesn't have a direction. So talk about power in the context of sprinting specifically, since it is a scalar and has no direction by definition, it inherently ignores multiple dimensions. So multiple movement, multiple axes. So there's no direction. So we're talking about horizontal power. So if we're talking about power, then we're not only are we oversimplifying the mechanical demands to be successful, but we're also taking a step further away from the most relevant performance variable, which is velocity accumulating velocity. And you do that by applying greater force to the ground. And so power also is back calculated from the force and the velocity that's produced during sprint. So again, you're taking a step away in the wrong direction from the relevant performance variable and you're ignoring key mechanical factors that are at play. So if you're ignoring key mechanical factors, could you go into what are the key mechanical factors? Let's say somebody as a sprinter or somebody running locomotively, let's say, I mean, that would be running. But let's say we take a football player, a field athlete or a track athlete, what would be those, you know, those key, those key factors there. So we talk about what the force velocity or rather the power velocity curve looks like with sprinting. You see it's sort of an upside down you. So at the beginning of the sprint, since there's since you have no velocity really or a very low velocity at the start of a sprint because you have to accelerate up to your top speed, since you have a very low velocity, multiply that by whatever force you're applying, you're still going to get like no power essentially at the beginning of the sprint. You make your way down the track and or the runway what would have you and you your whole body power peaks out at a certain point, but then it drops right back down to zero when you have a lot of this velocity, but you have a net force of zero because the breaking and propulsive horizontal forces are now canceling each other out. So on one on one side of it, you have very low velocity and so you have little to no power and then on the other side, you have you have no net force, so you have little to no power there. So that's a misinterpretation of power velocity relationship and the force velocity relationship, it takes a lab phenomenon with from isolated muscle fibers and isolated muscle muscles. And applies it to the whole body, whereas we know that that's not how the force velocity relationship works at the whole body level. We have joint dynamics and tendons are contributing to the force output. So we're we're we're a misapplying the force velocity relationship to whole body movements and we're getting these miscalculation and misinterpretation of power output. And going back to the fact that power is a scalar quantity and not a vector and ignores the vertical dimension. And if we're talking about, you know, having no power at the beginning of the sprint and no power when you're at top speed, it's sort of even at face value doesn't make any sense. So we're applying, you know, large amounts of force and we have large amounts of muscle length chains happening lots of muscle shortening happening in the, you know, let's talk about the sprint start, for example. So you get into a bunched up position. So you have your, you know, you may be your knees at 90 degrees, your back, your back leg a little bit more than 90 degrees. And then the gun goes off or or or the whistle or the or the ghost signal. You get and suddenly you have to you have to contract. Decentrically, so you actually have a length change. So you have a shortening velocity on top of the force that you're having to produce. So you have high velocity and high force. You don't have high high force and no velocity and then basically zero power output. So you do have some power output during the initial push of a sprint. But then as it will make you wait at top speed, then the muscle behavior is now different. If you if we're applying the same force velocity or relationship or rather misapplying it, then it would, that relationship would have you thinking that there's a lot of muscle shortening happening at top speed. When really the muscles are are acting what we call quasi isometrically. So there's maybe a little bit of shortening. There's when you come off the ground and then you swing your legs in the air and then you touch the ground again. And there's a little bit of eccentric lengthening. But really the elastic elements of the muscle and the tendons are what's taking up most of the length change and providing most of the mechanical work. Okay, so when when you're mentioning that because I was trying to think through this as far as like that top speed and then even how you're talking about like the quasi isometric occurrence. Do you see going on maybe slightly into the technical aspect. Do you see different movement strategy types based off the type of athlete that you would be analyzing or based off of the type of sport. They're playing let's say a field sport or court sport athlete versus a sprinter. Do you see different strategies based off of individuals and they still might be running at a relatively high speed in comparison to others in their in their sport. Sure. Yeah. So what's this thing about to two athletes who are both for just for simplistic numbers. Let's go 10 meters per second. That's their top running out of top speed of 10 meters per second. We could have two two pretty different ways of skinning the cat. So you have one one person maybe is getting a little bit more distance out of each step. Whereas the other with the other individual is maybe more effective at turning their their strides over so they maybe have a little bit more frequency other strides. So per unit distance they maybe get more steps. Whereas the other individual might be getting longer steps overall. So fewer in number. But I was having this conversation with somebody just the other day. I'm never going to say that, oh, there's so many different ways to skin a cat. You can have somebody who has this strategy that's completely different from this person who's running the same speed, but in a completely different way. I mean, yes, there's going to be some variation, but within a tight range, there's going to be a tight range of possibilities for how we can be effective at a certain running velocity or how we can apply force. It's going to be largely dictated by your entrance and abilities. It's going to be dictated, imparted by your stature, your anatomy, your body dimensions. So yeah, while there's going to be some variation from person to person, it all sort of operates within a tight range of ability. Our podcast is sponsored by our own strength training app, Peak Strength. Peak Strength is entirely based around our training system that we use here at Karaj Strength, and we have our own speed-based programs inside of Peak Strength. All you have to do is click the first link in the description, head over to peakstrength.app, the Google Play Store or the Apple iOS Store, and when you download Peak Strength, make sure that you put in your email and then you want to select the program based off of sprint-based programming, or maybe if you want to train for athletic fitness, you want to get explosive, you want to be healthy, you also want to look good, click that athletic fitness, and then finally, if you're watching this in the first quarter of 2026, make sure that you're going on 90 days of cultivation challenge. This is a challenge where we're trying to instill the proper habits for you guys to get healthier, to get more explosive, to get faster and improve your endurance. Now, let's get back to speed training with Dr. Lance Brooks. So I guess based off of that, if you're looking at slight variation and isn't just length of a stride versus turnover that you typically see, and I guess where I wanted to go with this a little bit was like, when you see the, I'm from a track background, I'm a shop putter, and I typically would, I would associate someone like a sofa pal or Justin Gatlin or Noah Lyles like this, a bit more extended, more upright, and then you sort of, I sort of hear these like squatty people, squatty runner type people, and my visual is like a wrestler running almost, and they'll talk about, no, it's more of a squat. I guess do you see anything that would make that accurate to a point and how far down the line do you think is a reasonable discussion where like, I mentioned this to Dr. Clark, where I was like, maybe Sequan is like the Squat, Sequan Barkley is a squatty or runner, but is it that much different from, you know, the a sofa pal model, I guess. Right, so do you want me to address squatty running specifically? Yeah, pretty much. So what squatty running is, you know, there's sort of the usual suspects you sort of promote this sort of thinking, and without, without being too harsh, I don't think that there's basically any value in this model of squatty running, because when we're talking about squatty running and, you know, how it's demonstrated and how, and particularly how it's explained and justified, where we're putting our limbs in joint angles where suddenly you're not able to cover as much distance with each stride. So you're putting yourself in a position where you're much less effective from stride to stride. You're also, you're compressing your limb in a way where now you're decreasing the effective mechanical advantage of the muscle acting on the limbs. And now you're increasing the force demand, all that the muscles, the tension demand that the muscles are having to produce in order to meet the same force requirements on the ground. And you're saying you're not able to do that from that posture. And you're decreasing your force output. So we were sort of in this, this, this, this realm of, you know, squatty running is, you know, trying to kind of bounce off the ground, almost let gravity make you fall forward of those sorts of things, or are mentioned along the same vein. And there's just, there's just no value to it. And we were talking about like, say one, barkly as an example that you brought up. I don't know that he's a squatty runner other than the fact that he is maybe spending less time in the air because of just, you know, the demands of his sport. So we're talking about linear, linear speed. And we're talking about the, you know, a soft power we're talking about, you saying bolts and, you know, these, these, you know, thoroughbred sprinters who, you know, running a straight line as fast as they possibly can. Their mechanical demands are a little different because, you know, from point A to point B, in a straight line, when you're sprinting, your, your, your mechanical demands are different in that you just, you know, maximize force on the ground, get in the air. You want to spend a lot of time in the air growing top speed, you know, apply forces to the ground as quickly as you possibly can in very large magnitudes. When we're talking about, on a football field, especially in competition, there's a lot more, you know, unpredictability in the environment. So you have to be able to, you know, change direction on a dime. And if you're doing, and if you're in the air, and if you're, you're adhering to the same sprint mechanics that elite sprinter would, then if you're doing it properly, then you're going to be spending a lot more time in the air. And that doesn't afford you the flexibility to be able to move from this direction to this direction based on what's happening in front of you. And elite sprinters don't have to deal with that during competition. It's very predictable. You're going from point A to point B in football is different. That's, that's great right there. So if you're looking at an elite sprinter, and I guess this is where I, along the lines of, of actual movement strategy, like, do you see that, or, or when you've researched, when you've studied elite sprinters, and when you're working with them, consulting with them, are you looking from like the hip down to the foot, or are you looking from the foot up to the hip? Where do you see, like, where do you really see the, the, the actual output coming from? And then where do you see it? Most of the leaks happening when you're, when you're analyzing this, you know, in, in your consulting and in your experience? Sure, I, um, I'll try not to speak in too much detail about the private consulting, I mean, specifics of what some of the athletes, but I'll just kind of give you a general overview. When we talk about what moves the needle in terms of sprint performance, really the way I look at it and the way I've, I've learned to look at it through all my training over the years is to go from the ground up because that's where the rubber meets the road is what's going to determine better outcomes for sprinters. The force on the ground and that's going to be determined by how much time you're able to apply that force. So if you, you have a, a very tight window, especially if, as you're moving faster down the track or down the football field, the, the time window that you have to apply, the requisite force to keep your body standing to, to continue sprinting is very, very narrow. So if we know how much time an athlete's spending on the ground and we know their body dimensions and we're able to measure the ground they're covering, then we can make estimates about the force that they're applying to the ground and how it's affecting basically the entire sprint from start to finish. So we talk about where a lot of the limitations I see or some of the problem areas that I look to address is if I have an athlete who is, you know, spending a lot of, a lot of time on the ground and not really getting a lot of, of distance out of their, out of their strides, then we, you know, that means that that says to me that maybe they're, they're trying to turn over their, they're focusing a little bit more on the frequency piece. So then we, we need to, you know, prescribe them solutions to, to teach them and rewire their movement patterns to where they're actually getting more out of their strides and not just focus on the fast turnover. So that could be, that's one example. We can also have the opposite problem where we have somebody who's like kind of doing a bounding strategy and they're not turning over the limbs at the rate that they probably should be. And so then they have a whole different set of solutions that we try to explore to address those things. And that's really just the top speed linear portion of it. But if we're talking about acceleration, we still have to look at stride dynamics. We try to hone in on, you know, the first 10 meters in where, where we have, you know, what we're leaving some performance on the table. And I've been finding with this model that I'm developing that have collaborated on that we're, that we're looking to publish and it looks to benefit sprinters and, you know, football, 40-yard dash combine athletes is individualizing their sprint start set. And it's going to be based on, I'm not going to give too much detail here because it's still something that we're working to get published. So, but it's, in essence, it's going to be determined by body dimensions, but not in the traditional sense of like a percent of leg length. It's a little deeper than that. And hopefully something that we'll be able to share in the not too distant future. So when you were mentioning like the runner who's a bounder or the runner versus the runner who spends so much time on the ground, but they're not covering a lot of distance, is do you think, and I know I'm asking you to speak for a represent, or for a population that you're sort of outside of. I was, I hear coaches talk about this where they'll say like, oh, this guy's a, a force driven runner and this athlete is more like elastic. And for me personally, I've always been like, what does that even mean? Like, It never made a ton of sense because no matter what, they have to apply for. So I'm saying, is that, what do you think, why do you think people define these runners in this regard, but what do you think they're trying to do? - This is a great question and I agree with you. I, the characterization doesn't make any sense. It's a false dichotomy. They're not mutually exclusive for synodasticity. In order to be one, you have to be the other. You need to have elastic, elastic qualities, elastic behavior, and to be able to apply very high forces to the ground in a short amount of time, in order to have successful outcomes. It's sort of paradoxical 'cause you wanna be stiff, but also have elastic behaviors, but all that to say is you're not gonna have one person who's super forceful and they have this, this success with running speed. And then there's other person who has the same success, but they're more elastic. You're not gonna have that. It's a false dichotomy, but it also kind of just stems from our very human need to just categorize things. We wanna categorize everything. And we're very uncomfortable with saying that certain things exist on this performance spectrum for lack of a better word. It can be, things can be a lot more fluid. We even have these quadrant systems that people put out there for various performance very performance phenomenon. We always wanna categorize stuff. And we're very uncomfortable when we're not able to do that. So that's really what that comes from. And I agree with you. It doesn't make a whole lot of sense. And hopefully, my explaining that they're not mutually exclusive. Hopefully that helps clear that up for anybody who's falling for that misconception. - I think it does. I think it actually, I've always felt like the term elastic, I think if we could define that for the audience. How would you and how does a scientific world define elastic or elastic qualities in regards to sprinting just so people can try to visualize that. - So we think about elasticity. We wanna think about spring-like behavior. But again, I wanna tread very carefully there because the human limb is not a spring. And we had the spring mass model from years ago where you treat the limb as if it's a spring and you're able to predict the force on the ground. But basically, it's all about being able to apply and return force from the ground to maintain forward motion. That's what we talk about when we're talking about being elastic off the ground is being able to store and return elastic energy on the ground. That's what we want. So you have different types of energy and we can only go, we really can only go so far and explain so much when we talk about locomotion in terms of energy exchange. But let's think about with the whole body or the center of mass is doing and how energy is being exchanged. So when you push off the ground for a step then your center of mass goes through sort of like a mini arc. And so at the top of the arc, you are maximized with your gravitational potential energy. And then as you, you know, as you kind of come back towards the ground to apply your foot to the ground, then gravitational potential energy is being converted into kinetic energy, right? So there's your center of mass energy exchange. You go potential appear and then kinetic as your body comes back down to the ground. What's happening with the behavior of the limb is when you apply force to the ground and you touch down the ground, then the muscles and the tendons, the elastic qualities there are being stretched. So now we're storing this elastic energy in the limb and then when we push off the ground, you know, to begin our cycling of the limbs for the next step, then all that elastic energy gets returned. So if we're able to effectively store and return that sort of energy to keep applying force and keep moving, that's sort of what we mean when we're talking about the elastic behavior. And it happens on a very small, very quick scale and really high forces and really high tension when we're talking about sprinting especially. - So very small, very high scale. Okay, this is where I'm trying to think through this 'cause it's like, as I'm trying to finish right in my notes from what you were just saying, is that, do you think that ability, okay? So the ability to apply a massive amount of force in a short period of time, like this impulse every step, right? Is that what coaches are using standardly right now, RSI, like the reactive strength index right now is what they're using to measure that quality. Is that what they're, is that why they're doing it? - Yeah, 'cause what I just described to you at the limb level is essentially the stretch shortening cycle. It's that ability to store and return elastic energy at the muscle level and the limb level. And by far, the most popular way to assess this is you have to give a different type of test, but drop jumps is a very popular one. But by far the most popular metric that has been used for the last, you know, what, 23rd years has been reactive strength index RSI. And its most common computation is jump height over contact time. And there's a couple other ways that it's formulated, but at the end of the day, it's still just coming down to that jump height over contact time. 'Cause even if you do aerial time, there's still a known relationship between time and the air. And jump height just based on projectile motion equations. So as far as, you know, suggesting that as a solution to RSI's many shortcomings, it doesn't really do it because maybe you fix the dimensional issues, but you don't, you don't address the mechanical misinterpretations and misappropriations. - So can we get into RSI then and break that down? Like where you see maybe the purpose of why, maybe a little deeper on why people wanted to use it, how they do it, but then the flaws even deeper. And then get into the dynamic rebound index and assets or aspects around that. - Sure, sure. So we'll see, you're also starting with RSI. Let's start with the most simple explanation of it and what its issues are. I would say it's not an unimportant and not worthwhile area of inquiry. I mean, we want to analyze, we want to evaluate shortening cycle function in these athletes. And so, you know, they come up with the reactive strength index. It's how high you can jump on, jump from the ground from a drop jump, for example, in how many times, and how much time are you applying force in order to do that? So it's sort of a, you almost want to think it's common sense that that would be the way you do it, right? But if we dig a little deeper and we're talking about, you know, talk about science and, you know, things have very specific definitions, things have very specific meanings in science. And if we want to move forward and have sport science, we take in serious as a, taken seriously as an academic discipline and a branch of discipline of science, then we need to, we need to improve some of the things that we're struggling with. And so, reactive strength index, just the first and foremost, if you, with any metric in science, any physical qualities or physical qualities in science, the first check that you need to go through in order to check its validity is do a dimensional analysis. And every physical quality in science can be broken down to three qualities or dimensions. They're called dimensions, so we have mass length and time. So you take any metric and you break it down to its component parts, either mass a length or a time or some combination of those three. And RSI, the units that come out is meters, jump height over seconds, contact time. So if you break those down to their dimensions, their, their, their fundamental qualities, then you have a length over a time. That's a velocity unit. And it's not a velocity. In fact, the, the jump height that length and the time in seconds are happening over two very different portions of the physical event. So the jump height is happening in the air and the contact time is happening when the foot's on the ground. So they're separated in that regard already. So it's definitely not a velocity. It's not even a pseudo velocity. It's just bad math. So that's the first issue. So, so with, with any other metric that might replace it, it would have to have consistent dimensions. That's the first problem. The second problem is RSI has this tendency to reward jumps where the contact time is really, really short, even if the jump height is not very large or the impulse of force by the ground is not very large. So it's sort of disproportionately rewards really, really quick, like, but jumps off the ground, like, you know, pops off the ground. So if you, if you, you can gain the system in that, in that way, to have a really short contact time, not very much height, and you can, your R size score. So any replacement metric would have to address that problem as well. If it doesn't disproportionately reward contact times, it would at least have to at least reward jumps where the contact time is short, but with a company large jump and high force. And then of course any metric that would replace RSI would have to in the real world still deal with the same easily accessible measures that contributes to R size appeal. It's very appealing to just be able to measure a jump height, measure a contact time with a jump mat or even video base and get a simple score that's going to assess your shortening cycle function. So any replacement metric would have to allow practitioners to take the same measures, not have to add anything to it and just get a better metric that's better in terms of mechanical interpretation, dimensional analysis, but then also ease of access. And the last problem with RSI or not the last one, there are there's many. The paper goes in detail. There's a whole theoretical modeling analysis that was done. So I encourage anybody who interested in these things. And we'll put it we'll put it in the description below too so people can see from your paper. Sure, sure. RSI is entirely indifferent to whatever incoming velocity or incoming drop height that you have. So if you drop from 20 centimeters, if you drop from 50 centimeters, RSI doesn't take that into account. So you can have very different ways of testing and very different demands in terms of vertical displacement demand and in reversing any incoming momentum that you have from a drop, but RSI is not able to do that. DRI on the other hand does take into account not only jump height, but also the incoming drop height. And then that's in the numerator. And the denominator is gravity times squared contact time. And the reason why it's gravity times squared contact time is that's just the GT squared. It's from basic, kinematic formulas. And so you get a length in the denominator, a length in the numerator. That fixes the dimensional analysis right away. But then we're also normalizing acceleration to, you know, to gravity. So now we have a much more mechanically sound metric that is, it's robust across movement strategy. So if you have RSI, if you, if you fix jump height, let's say you jump at the same exact height, but in one strategy, you're a little stiffer. And one strategy, you're a little more compliant. You get a little bit more of a dip when you touch the ground. RSI treats those as two completely different movements. And that's a problem. With DRI, and there's a really nice figure in the paper that demonstrates this, you have the stiff strategy and the effective strategy. RSI treats those two as completely different movements. And so there's no continuity with DRI. They're almost directly connected to each other. So you can actually see a nice little curved slope there that that that that that formulates the DRI across contact time. So again, I encourage anyway to go read that paper. It does a thorough, a thorough take down I think of RSI. So, but also not just pointing out the problem, but offering a solution. I think DRI is the solution. So let's say like using that as a solution as someone who, I mean, full disclosure, I do not use RSI at all. I will use like very simple metrics for assessing like the explosiveness aspect might be through like a vertical jump. And we're just testing a vertical jump. I guess my question here would be if I would use, if I would start using as someone with a gym and training athletes, if I would start using the dynamic rebound index, how would I go about doing this? And let's say like, so for me personally, we were measuring 200 plus athletes every 13 to 16 weeks. And this is a range from sprinters to football players to wrestlers to throwers to marathon runners and swimmers, stuff like that. How would you go about or how do you, how would I go about doing that as far as adding that into some type of assessment? So, a lot of people are already doing it. Really a lot of there's a lot of people now with force plates. I mean, you have your jump mats. You have your your switchboard type jump mats. I have a friend who manufactures those who do it really well with them. So you have these you have all these methods for collecting time on the ground. You have different ways to get jump high whether you calculate it from time to air, whether you literally measure it from from a vertex or you do it from a force plate. So there's in the especially in the paper, I wanted to make sure that you could draw specific pathways to from all these different measuring methods, whether you're using time, whether you're using jump height in time or whether you're going from vertical force from a force plate. And you can go through all those pathways and still get to DRI depending on you, you follow the the mathematical track there to get there. But you know, as far as as far as adding these sorts of assessments into a system that you that you have as far as training testing your athletes, I think that's just going to that's going to be up to the practitioner. I tend to stay out of those those debates about when or whether you should incorporate these things in training. Everyone's got a different opinion on it. Everyone I personally think that it's valuable because you can only sprint at max effort so often and it's so much volume. So sometimes you need to find other creative ways to to challenge the stretch shortening cycle and being able to test that with a mechanically sound and mathematically coherent metric is really important in order to do that. But as far as if if you're somebody who's who's never dealt with RSI and you see value in DRI and you want to incorporate it into your systems, then the easiest way I recommend going about it is just you know video-based timing. It's super easy. Everyone's got a high-speed camera in their pocket at 240 hertz. You can as long as you know the drop height what you show you can measure that. Then you can you drop from a box you can push on the ground and calculate time in the air and the paper outlines exactly calculate DRI from that. Yeah, I think that's the that's the interesting part there is it's like it's not that challenging as far as it's not it's not much more challenging than even say like measuring someone's vertical jump on a vertex like it's and even if you're looking at the jump the jump mats like jump mats are always a little bit interesting because you can you can skew them quite a bit more than a vertex I believe. Vertek you can skew on like when you reach but if you have someone who's like no like let's go we got to reach a little bit more and you can take an image of the first time that you're measuring them. It is relatively easy to apply. I guess the next question that I have with the dynamic rebound index is then do you see some type of if if this is high or low what what are the trends that you end up or have you have you gone into this enough where you might have a practitioner implementing this and they're like go when this is high this other aspect this other time like a flying ten or or or even their their a ten meter acceleration do you see any very clear direct correlation I know it's early but do you see any direct correlation with those you know DRI directly implemented with measurement of speed on the track or speed in a sprint on the on the turf. Well it's it's going to be it's going to be not really different from some of the stuff that we've seen with RSI in the in the perceived value with RSI is you're you're really just trying to evaluate in most cases the stretch shorting cycle function with the two lens at the same time so if you if you were to just like guess I would say yeah there's there's probably going to be some correlation between they probably a decently strong relationship between an effective DRI score and your ability to quickly apply force to the ground now whether that's going to directly translate to you know a faster 100 I mean it could indirectly because if you know if force on the ground in a quick time period is one of the strategies one of the important strategies for having an effective 100 meter sprint then yeah I mean probably a few a few rows removed but yeah there's there's there's likely going to be some sort of a relationship there causal relationship there but you know with this theoretical paper just being published the next obvious step is to to get a pool of test subjects and you know have them have them go through a series of varying drop heights varying contact times and efforts and seeing how how the those different moving strategies behave with the RRI compared to RSI I mean we already did it with we already did it mathematically so There's no reason to suspect that the math's gonna change when we start doing it with Actual test subjects, but that's the next logical extension is to get some collect some real-world data. I guess how do you how do you see? Could you do the same type of analysis just from a single joint? In what sense like like somebody drops on the on the left foot just their left foot and they react back up like could you just Yeah, yeah, you can do a single like you do single like DRI for sure and then use that I feel like they're in and I don't know Maybe this is getting too into the dynamic correspondence stuff, but it's like could that be a way of having a tighter correlation Maybe and I think giving it a little bit more specificity. Yeah, I don't know because when you're coming in from a drop That's already not really gonna be Super specific to the sort of eccentric demand that comes from sprinting. So, you know, maybe maybe not So okay, that that would be where the next day if we would get into like the applied aspect even further than it's like I did see you By the way you I forget if you still have the the graphics up, but like when This is going back like two three four years ago I think when you were when you were still at SMU used to put the best graphics up and I would take screenshots to try and like Wrap my head around everything that you were posting That's a whole total side. I saw you you were working with I think it was like a combine group or a pro-day group If you're looking at like those aspects and then if we go back into the sprint in the performance realm of like Sprinters and and football athletes or soccer Based off of your experience in consulting Do you see any like what do you see outside of DRI that could be like the best predictors of Performance on the field or or maybe even in maybe even speed specifically like any specific test like a flying 10 like a 40 like a shadow Like anything along those lines that you like dude if we're talking about straight speed or even a ability to cut These are the best tests that we can see I guess that that's my my first question in regard to the applied world So it's somebody listening right here. It could be like all right. These are the best representations for football or the best representations for You know sprinting in the track Yeah Great question and The I feel like the cop out answer that everyone's gonna that everyone gives or everyone should give I'm my in my opinion is it just depends You know, it depends on in football. It depends on the position, right? I mean we got O lineman who Never in their entire playing careers will will almost ever run 40 40 yards in total distance on a given play. That's just that just almost never happens for for an offensive lineman, right? So we're talking about what sort of like you know sprint running tests or or whole body movement tests of this kind Local motor test that we can that we can look at to predict some form of success For a football player. It's gonna be position specific something like we can go zero to five for a For an o-lime in for example for for a wide receiver. That's gonna be a little different. Maybe we can start getting you know looking at 40 yard dashes or even fly tens those kinds of things It was talking about track athletes You know apart from just doing doing the entire sprint if we're just talking about isolating Certain athletic qualities. Then yeah, those fly tens are gonna be a great way to approximate what your what your top speed performance in Kinetics and kinematics are gonna look like so a big fan of fly tens at near max speed near max effort But of course if you especially if you're a hundred meter 60 meter sprinter even 200 meter sprinter That early acceleration is also gonna be important. So we want to look at you know zero to ten or zero to 20 that kind of thing If you if you have a clear idea of how they're performing in the first ten meters and the ten meters where they're at top speed Then if you just you know if you don't want them running a whole hundred then if you can ice like those two I select those two portions of their sprint you can you can learn a lot about where they're leaving some performance on the table and help them make adjustments I guess this is where it's like and maybe I'm taking a step back home Back into the oricide dynamic rebound index, but even here I Feel like you're simplifying it really well where it's like look if you're an o-limin and you're measuring a zero to five or a zero to ten Like you're probably gonna get a good reading back at the state of this athlete same thing with a flying ten for a wide receiver Same thing with you know you maybe a flying ten for a sprinter, but you could put it at 10 meters 20 meters 30 meters 40 meters And we could see where they're at as far as their them coming down the track Um, I wanted to go back into that because your simplifying is really well where it's pretty easy I have felt and I feel and and I think you and then there's another Researcher named Dan Cleether who I think does a pretty a very good job of attacking The force velocity curve and I think I sort of lump our SI into this realm of like Practitioners some strength coach like myself wants to I like to pretend I am more of like this High level you know research laid in coach And I think when that happens we get lost in things like RSI and force velocity curve and I guess I wanted to see like Can you punch holes like in the force velocity curve? Why has that taken so much ground? Why are we still teaching this in college? And is it applicable even in in the realm of performance? Good question. I want to be very very clear The force velocity curve is Nearly infinitely valuable when we're talking about explaining Function at the muscle and limb level and how it expands and triples upward Uh, uh, of larger um, higher scales of biological organization. So a force velocity curve Extremely important. I rely on it all the time It's it's where it gets misunderstood and misinterpreted and misappropriated Where a lot of the confusion comes in because the force velocity curve is a lab-based phenomenon that we observe in isolated muscle and isolated muscle fibers and in the in the biological lab setting and I've done work with isolated muscles and animal models And so I see it for I've seen it first hand and it is explained It's already for a whole body movement Where it gets misappropriated is when we start talking about Signing different exercises to different portions of that that exponential curve and you have on one side You have sprinting it's really high velocity, but somehow they say that it's low force Um, and then on the other side you have like a you know a mid thigh pull or something like that and it's no velocity But it's really high force and so and then you have all the ones in between you have like you know power cleans you have trap trap bars jumps those kind of inches like and they fill in this this this curve with all these different All these different exercises that are supposedly going to help you target different parts of the curve And so you're told to surf the curve, right? That is that's a misinterpretation of how how it works We can we can't say that there's a force velocity relationship in that way for whole body movement But what we can say is that there is a load and movement velocity Relationships certainly and it's gonna be more linear. It's not gonna have that sort of a negative exponential shape. It's not gonna have that it's gonna be more linear and You're certainly not gonna be able to take specific Movements and exercises and target certain portions of that curve It's really just about how much load are you putting on a bar and how quickly are you able to move that load And that's a linear relationship and because we're because we now are including joint dynamics that Compensate they're in different parts depending on mechanical advantage and your relationship with gravity and tendons are starting to play a larger role in some of this stuff. So Yeah, again, it's just it's just a misunderstanding of forced velocity curves origins It's usage and how it applies to whole body movement. It's just that plain ensemble That's very Clear the way you just laid that out too. It's like look. It's useful here But it's horrifically unuseful here and we should not use it this way period Um and and and going into the load velocity and how you explain that makes a lot of sense I guess one of the things too that I I guess from an applied perspective is and then When you're looking at when you're consulting are do you see any type of relationship where let's say Um, I'm trying to think through how a kid maybe a kid still listening hopefully right now and they're they're going okay What could I do to get faster like is there Because I feel like there's one aspect of a kid just starts lifting or they just start exercising the first two to three years You're probably going to be able to squat more and get faster But there comes a point where that just does not happen anymore And I guess where I wanted to go is in your experience maybe want it when you were coaching but even more so now as you are deeper into into the research Do you see any like direct lifts plyometrics exercises that you're like look At the end of the day, outside of one you have to sprint to get faster. These are some clear movements that will help you as far as speed is concerned. Yeah, so if I could just take like a really simple theoretical example and just say, you know, someone comes with their 12 year old and they say, we want to get this kid faster. You know, he's trying out for such and such team and we just want to see where he's at, where he can improve. That task is going to be a lot simpler and more straightforward than if I'm working with one of my Limpians, right? It's going to be, it's going to be a much more manageable straightforward endeavor. We'll just take a look and just like with anything, you're going to have a lot of those like, you know, newbie gains. Like you get like somebody who's never lifted weights before and they go into the gym and, you know, they start seeing progress rather quickly. You start exposing a kid to the right kind of stimulus and get them, get them sprinting with max effort, you know, and in a short time frame, they're going to start seeing improvements. But of course, you know, we've all seen, you know, young kids run, they don't exactly look like Justin Gatlin or you say both. So there's going to be some aspects of their kinematics, their movement patterns that you can, you know, take them through some drills and help them kind of instill that motor pattern of effective force on the ground and effective limb, you know, limb repositioning and that plus intensity and just polishing their movement patterns, you know, within a few weeks you can start seeing some some some really substantial progress with that kind of population. When you start going to the much more seasoned athletes, you have to zoom in and dig a little bit deeper into where their gaps are in their performance. And that's when that's when my services become much more valuable with someone who's like, you know, 10 years old and they haven't really worked with any kind of speed coach or anything like that. Then I can help, but you know, there's a lot there's a lot of other individuals out there who, as long as you get them on a good speed program with somebody who, you know, even halfway knows what they're doing, then you'll start seeing some stuff. Where my where my skills and actually what she's become valuable is when the coaches no longer know where to go and they need to dig deeper with some of their leads and they're like, you know, where what am I not seeing? Then that's when my services become very valuable. So in that regard, what would you see? Yeah, let's say I because the pro day comes first of mine, but also I've seen videos with Dr. Clark with Ralph Man analyzing like, let's say no allows what would be like an example and an elite group that might be like, look, these are some areas that based off of the, you know, the inconsistent models that we followed in the biggest flaws and understanding speed and power. This is like typically a consistent theme. This specific problem is a consistent theme when I am in analyzing an elite group. Could you provide something like that? I don't know if you can. Yeah, maybe off camera them because we might be getting into some stuff that's proprietary for not only just me, but also some individuals that I'm vaguely familiar with their systems. I don't want to give any of their sauce away. But yeah, that could be something that we chat about in a little more of a private setting. So on the factor of let's talk about this because Stubic Millen sort of related and maybe this is where I could ask it a little different way. He related to me the foot making contact with the ground and he's like, yeah, it's a hard thing to think like we want foot stiffness, right? And even Dr. Clark had mentioned this around foot stiffness and like, you know, sometimes the foot might drop and even in someone like Bolt, you might see the heel drops too much and then the next one he fixes it on the same sprint like there's varying aspects of that. Do you see like foot strength as someone who does look typically from the ground up? Foot strength or foot stability could be a low barrier of entry for younger kids and maybe even how would you like foot strength as a low barrier of entry to improve speed, but then also is there a point in using isometrics to improve foot strength? I know there's like two different questions there. Yeah, no, I'll try to address them than both. Yeah, I think foot strength, foot stiffness, however you want to characterize it. Yeah, that's something that's going to be important. It's going to be valuable for someone who's trying to, you know, apply large amounts of force into the ground in a very short time window. You need that sort of stiffness in order to apply that. You need it throughout the limb. You needed it from the foot all the way up to the hip. You know, when you're in mid stance, you need to be, you know, with a relatively straight leg. That's how it's going to look. If you have two compliance, if you're too compliant anywhere in that system, you're going to leak some force out and you're not going to be as quiet as effective. So yeah, that would be an important physical quality to look at. Reminding me of the second part of that question. Using using isometrics to improve foot stiffness or ankle stiffness or any aspect around sprint based training. In my opinion, the kinds of isometrics that you see that you see happening in the weight group setting and these sorts of things that they're hoping that their hope is to to transfer into sprinting. In my opinion, I don't know that that's going to be ultimately very valuable because the mechanical context under which you're doing those isometrics is so different from the mechanical context of the footstripping the ground during sprinting. And it all comes down to the fact that you're not counting for the timing. You're not counting for the timing of the force that you need to apply. So when you're doing these prolonged isometrics, sure, yeah, you're able to maintain high intensity isometric stiffness for x number of seconds, but you don't have x number of seconds. You have point x seconds to do to apply the force that you need on the ground. So if you ask my opinion, I don't see quite the value in doing those kinds of isometrics if you're trying to apply them to sprinting. What's up guys? Our podcast and our channel are sponsored by our own strength training app peak strength. The entire focus of peak strength is to provide you guys with the absolute best sports performance app that you could ever imagine. We build out the programs on the back end. We take in all of these different decisions that we learned here on site at garage strength so that we can then apply it to you so you can improve your training. So if you guys want to improve your overall sports performance, head over to peakstrength.app. The Google Play Store or the Apple iOS store download peak strength. You'll go to free week of training and then you can start getting on those gains, get those reps done so that you can become a champion. Now let's get back to the video. Peace. Okay, I love that. Okay, I wanted to get into one of the podcasts I listened to to you explain breaking forces and how and even when Dr. Clark was here, he clarified like, look, it's going to happen. Now there's a range that you wanted to happen within. But I think what if you could clarify why they're necessary and it's not inherently this horrible thing if you have them in the right position and how they can be beneficial to sprinting faster because I think when I was listening as a strength coach, I'm listening to, oh my gosh, this guy thinks breaking forces are okay. And then you, you know, you rolled through and you're listening to what Clark was mentioning about where the foot placement needs to be. But then also when you explained it, it was like, holy shit. Okay, I get it now. And I could you go into the breaking forces when we see someone sprinting at max velocity? Sure, sure. So I'll just start by saying that breaking forces are a mechanical requirement. They are, they are required for effective locomotion and you apply breaking forces through all modes of locomotion. So let me just talk about how the forces are applied at various portions of the sprint. So let's just talk about 100 meters, right? Let's talk 100 meter sprint block start all the way to the finish line. During the block start, you have, that's the portion of the sprint where you're applying the highest amount of horizontal propulsive force right there in the block start. Gun goes off, you start pushing back on the pedal, the horizontal force, sky rockets, vertical force is, the hover is around body weight, maybe a little bit more because you do need to get into the air a little bit so you want to, you see body weight just a little bit in the vertical direction. You swing your limbs around, you're in the air, you hit the ground and when you hit the ground on step one, right out of the block, that's where you that's where you apply your first breaking force. People say, oh, in acceleration, it's all about minimizing breaking force and then top speed, you want to minimize breaking force. No, you apply your first breaking force the moment your foot touches down on the ground after you leave the blocks, that's just it happens. The breaking force is very small though because you hopefully maintained a pretty forward leaning orientation and angle in terms of your body position. So your horizontal propulsive force is going to be not quite as large but still large and your breaking force when you touch the ground is going to be pretty minimal. Vertical force goes up, up, up because as you move your way down the track and suddenly you're spending less time on the ground and more time in the air, the time that you have available to push on the ground and apply force is you need to apply the necessary force in order to support your body weight. So if you take your your body weight and squeeze it into a really tight timeframe, then that's the vertical force demand. And that gets larger and larger as you approach top speed. So that's it for vertical force. Going back to horizontal force. If you love the blocks, you applied your first braking force. The next step, your horizontal force is to get a little smaller, propulsive braking. It's a little larger. As you make your way up the top speed, and now you're a little bit more vertical and upright in your maintaining a steady velocity at top speed, you have to have an equal propulsive and equal braking force because you can't accelerate infinitely. It's just Newton's law at equal M A force, equal to mass-time acceleration. If you have a net positive force, you're going to have a positive acceleration, but you can't accelerate infinitely. So that propulsive force has to get smaller as you approach a steady state. And the braking force has to get larger as you approach a steady state until they ultimately equal out to a net of zero, and now you're moving at a steady state. So if we talk about, oh, and then of course after you get to top speed, you can start to fatigue and slow down, then now the braking forces are outweighing the propulsive forces, and now you're losing velocity, and then you get to 100 meters and the race is over. You know, we talk about the vector, the force vector. That's really just the direction and the magnitude of the push on the ground, and you only ever push in one direction. I know we talk about vertical force, we talk about horizontal force, but in reality, you're really only pushing in one direction, and that's the direction of the vector. If we're talking about top speed, or really anywhere, the vector needs to track through the center of mass. And the reason why when you push on the ground, it has to track through the center of mass, is because if it's a misaligned with the center of mass, you're going to rotate. You're going to rotate forward, you're going to rotate backward, you're going to lose balance. So the vector has to track through the center of mass. So when you're at top speed, and assuming you don't want to do a summer saw, then you need to strike the ground in front of you so that the vector can track through the center of mass, and then when the center of mass pivots over the foot, then it's pointing in the forward direction. So you have a braking force, and then a propulsive force on toe off. So the braking forces are a requirement not only for the steady state velocity, but also for the maintenance of balance. Yeah, that makes sense. As you write when you just describe that braking for, or the planning of the foot just in front of the center of mass, that for the balance perspective, that was great. I love that as a relatively simple way to try and visualize and understand it. I got one more question, and this is going to go back to your consulting company to a point is, if I'm looking at Brooks performance methods, and I want to say, I'm a 400 meter runner, and I want to run 100. I want to come down and run 100 because they make more money than I do. What are some things in that regard, or maybe even 800 meter runner running to come down to the four? What are some things that you would see classically from the longer distances for the eight, maybe the two to a point that they would have to try and improve getting down to the two and the one. Right. It's funny you ask that because I literally have an elite sprinter who that's the exact dilemma. 400 meter runner wants to get down into the one. So I can speak from experience in this. When we talk about top speed mechanics, there's going to be some things that you need to tighten up just a little bit in terms of helping them apply the more effective force in the smaller time window because the pacing strategy for a 400 meter is going to be different. Even though it's still max effort, the 400 meter, there's going to be more of a pacing strategy than there is during the 100. The 100 is full bore start to finish. There's not really a pacing strategy. There kind of is in a sense, but it's still max effort all the way through. 400, you've got to be a little bit more of a strategy involved there. So that's top speed stuff, but that's pretty simple fix because they know what's required. You just kind of help them get there a little bit. Where you really see the performance being left on the table, it's sort of that early acceleration because the block start is far more important. The first 10 meters is far more important in a 100 meter than it is in a 400 meter. So that's what we really direct our attention at first is to polish them up in the first the first 5, 10, 20 meters into that transition because it's a different ball game when you're going from 400 to 100. So yeah, I think in short, without going too deep into those things, that is a, those are sort of where I see the deficiencies with the guy going from a longer distance, who wants to get into the shorter differences and really hang with the big boys in that event. That's great because I think this does tie back into even what you said earlier, where you mentioned the aspect around what you're working on in your research and the start position related to specific aspects of limb length and body structure. One more thing I'll say about that actually is another thing that I'll see with someone who's going from that sort of intermediate, you know, longer distance or mid-distance person wanting to get into shorter events is particularly for 400, there's sort of a standard body type that has success in that event and it's going to be a little bit different than the body types that have more success in the shorter distance, like a 60 or 100. So taking somebody who is built to have success in the 400 and then showing them how they can still be effective in the 100, but you need to work around their body dimensions in order to help them have success because if you have a guy who's 6'3" or 6'4", they're going to have a different mechanical strategy to get from 0 to 100 meters than somebody who's 5'7". Okay, perfect. That leads it. Okay, one more question before I want you to plug your company and we'll plug the brand new research paper that's that'll be in the description. If we have one aspect here, like technical models, like if I'm looking at the 100 and if I'm looking at field or court sports, do you have like if a kid's watching that there's a sprinter or a football player or a basketball player, whoever it might be, do you have models that you say like, okay, these are solid models to start with and then build off of there and then in five years when you're really fast hit me up at Brooks Performance Methods. I do have, so the whole thing with Brooks Performance Methods is it sits upon three pillars. We have training, testing and teaching. A lot of the consulting services they go through the testing and the teaching stuff, so the teaching is for athletes but really geared to practitioners and coaches and those sorts of things. The testing is for anybody who needs those types of services and I work with, you know, I work with young students, I work with elites all over the place, but to answer that question, the training portion of the consulting services is I do have a standard start at starting out plan for somebody who maybe has never had a speed program, who maybe has had a speed program and they're looking to change things up. Yeah, I do have an eight-week program on my website, Brooks Performance Methods, you can find that by just going to the URL or you can go to my Instagram page, Lance Brooks, underscore PhD and find my website and my company page from there and explore all the different training and testing/teaching solutions that we have to offer. So yeah, I do have a good starting out plan for somebody who wants to have a low barrier to improve some speed performance before maybe getting a little more serious in going with our testing services. Would you tell them to watch if somebody hits you up in a DM? Would you tell them to watch like a specific sprinter like like Gatlin or Powell or a specific football player like to learn or you like, hey just run and do this or just do this program and then come back to me. I think it's just run, I think it's do the program work hard, every individual is different and they're going to have different needs based on their different context. So it's tough to point them to an individual to mimic because the person that they're mimicking might not be employing the same strategy that this person is going to need in order to have success. Everyone's got a little bit of a different context that they're dealing with. Absolutely, okay. All right, Dr. Lance Brooks, thanks for being on the podcast. This was awesome and I hope everybody took a ton of notes. Thanks for having me. Peace!