Better Than RSI: The Simple Formula…

What's up y'all welcome back to another episode of the Chikimid Weiki where we are making strength conditioning not boring anymore. Before we get into today's episode please hit that like and subscribe button. It helps the show grow and it costs you $0. In today's episode I am joined by coach, coach doctor Lance Brooks. And in this episode we mainly talk about dynamic rebound index and why that is a much better metric to measure explosive power for your athletes than utilizing RSI. I did my research study and my dissertation on RSI and I'll tell you what by the end of this conversation he is right. Dynamic rebound index is a fantastic variable that you should use and it's very simple to calculate. 2026 ends the three year current CEU cycle for the NSCA. Do not wait until December 31st, 2026 to get your CEU submitted to the NSCA. Get it taken care of now with an annual membership to strength coach network where you will get access to performance coaching 101, 102, 103 with each course giving you access to 2.0 NSCA CEUs. If you also need CSCCA CEUs those same courses come with 10 CEUs to the CSCCA. If you need CEUs to the NSCA, CSCCA you need help getting reinstated by going through all the process for the CSCCA from last year or you want to just make sure you knock out everything for this NSCA with this year, 2026 being a reporting period. Please reach out to us at [email protected]. We will get you taken care of. We'll help you get everything lined up so you can keep your certification and you don't have to worry about anything other than coaching your athletes. Again, you can click the link down below for more information or email us at [email protected]. It's got the snow that we just got last night. It moves pretty quick. Yeah, we got like 18 inches. A couple weeks ago. I think they're predicting something similar this coming weekend. I hope not because I'm having to shift all my class schedules around for my students. There's been too many scheduling snaffos recently for various reasons. Have another snow day on Monday would be not ideal. Bridgewater, it's a commuter school too. That will definitely impact how much whether they delay stuff or whatnot. For sure. For sure. I mean, so jump right out of the gate, everybody. Lance is now at my alma mater, Bridgewater State. What are you doing out there? What is your day to day look like right now? Right now, predominantly, I'm teaching the biomechanics courses. I am teaching developmental kinesiology, which is basically movements in motor development across the lifespan. And a graduate level capstone course on how to interpret data in movement science. Oh, wow. That's a fun one. So, what is that? Everybody heard that. They're like, okay, what is the labens term for lack of it? What does that mean in terms of the content that you're teaching? So when we think about the scientific method and the scientific process, you have your hypothesis formation, your experimentation, the data collection, the data interpretation, and then the communication drawing conclusions. So we're not focused on the entire scientific method. We're really zooming in on once you have the data or the data that's out there in the literature. How can you take the numbers, the quantities, and interpret and form actual conclusions and tell a story with the data? And how can data lie to you? How can it be used to spin the narrative that maybe is not true? And how can you identify this thing? So that's the focus of that course. It's a fun one. It's a challenging one in terms of the conversations that we have. We push back on each other and we call out assumptions, which some assumptions are necessary, some are maybe irresponsible when it comes to data interpretation. And so it's all about ironing out those things and being responsible with our claims. Now for anybody, the stray coaches that are like, oh, that data sounds boring to me. Why is it important? And one of the things I'll point to a study that was done in 2014 is when it came out, but it was done looking back on research for Oklahoma State football players. And it looked at their improvement from freshman year to their senior year, because that was back when it was truly just a four year development. And it talked about how there was no statistically significant difference. And athletes didn't get faster from freshman year to senior year, but they actually did. Like lineman gained weight and ran faster. Years three to four, it was the exact same speed. And the DBS and the receivers literally ran faster times. And I'll be it, I think it was like eight one hundred eight one thousandths of a second. So they went from like a four five eight to a four five zero from freshman year to senior year. So to like a strength coach is like that's significant, but a research analysis would say it's not. And sometimes that's why strength coaches are like, see, this is why I don't read research. It's bullshit saying that it doesn't matter, right? Like, what would you say to a strength coach that says that? I mean, it depends. I would never, as even a researcher, academic, say that a difference like that is not significant. According to course, it is. When you're getting faster, you're getting faster. For the strength coach, that's is wary of data and wary of science as a process and science as a way of knowing. I would say you to open up your view in terms of how do you even get your athletes better? You get your athletes by relying on your observations. And if you're if you're progressive or a good coach, hopefully you are measuring things and you are keeping track of progress. So you're already employing somewhat of a scientific process to your own coaching practice. So in terms of being skeptical of what the scientific process and what quantities and data and numbers can do is to serve you and your athletes or your clinical population or your patients is that's a short-sighted view. But you also say it's kind of short-sighted how sports science gets applied nowadays where instead of asking a hypothesis, "Hey, we see a problem. We want to investigate it. It's more like, "Hey, let's just get this and do this because that's what everybody else is doing." Yeah, it's all, yeah, of course. I think I have a, obviously, a little bit probably going to dive much deeper into this topic today because I have a lot of thoughts about it. But yeah, the way sports science is applied today is, and I've talked to this about, I've talked about this a lot of different people recently, that we live in a time for good or bad where the access to technology, research level, quality technology is being democratized at a rate that is severely outpacing the specialized knowledge for how to use them and the data of scientific literacy. So we have this really interesting phenomenon happening where individuals, coaches, who they want to employ a scientific process to their training in their systems. And they assume that just getting better, fancier technology is going to automatically serve them when really they're being handed research, laboratory, quality, grade equipment that they don't fully understand how to use and what the data that they get from them can actually tell them about what's happening in terms of the phenomenon in front of them. So that's a huge problem. It's just the access to technology outpacing the knowledge for how to use them. How do you fix that then? Oh, you just got to, we have to fight that battle again, scientific literacy. We have to, that's sort of part of my role, not only in my capacity as professor, but also my capacity as hopefully a constantly evolving and improving scientific communicator. So having these types of conversations where we can identify the problem, but then hopefully through the course of time, having better solutions. And a lot of that comes from, you know, I'm no longer in 100% applied space of, you know, making up, setting up weight rooms and counting repetitions and those kinds of things. So I'm not in a straight, the conditioning environment anymore. I used to be. That's just, that's my role within the field is sort of this space is, you know, helping coaches and athletes have, you know, gained a deeper understanding about what's, what are the mechanical and physiological happenings with their athletes and how can we improve them and identify holes in their game. And then part of that was from the athlete level is figuring out those mechanical issues, those physiological issues, but then from the coaches standpoint, it's really those, those knowledge gaps and helping them, helping them bridge gaps in their practice, whether it's, whether it's understanding why a certain drill or technique works the way it does and why others don't. And we'll talk probably about a little bit about RSI and DRI, but another, another key responsibility of mine as an academic in this space is to keep publishing research and work that hopefully can offer improved solutions in ways of assessing our athletes. So DRI, I would point to you as a recent example. example of that. Huh. Team Bill or Strength Coach Networks trusted provider for online software for strength coaches. Does not matter what sector of strength tradition you work in, you want to get team building because you will be able to program for your athletes, simply distribute the training to them and make changes, modifications, whatever you need. I've been utilizing them since 2019 when I was back at Towson. I still use it in person at Goldfinch with all my remote clients throughout the country. And in person at the high school Centennial High right down the road when I was volunteering for them. You got to check out Team Bill during the link down below. The people that work for them are former strength conditioning coaches so they get it. They are able to help you with all of your needs. Again, reach out to your team builder rep and learn more about them in the link down below. How about any of the strength coaches that are like, okay, outs when you when you're reading research is really good standardization of methods in terms of like, hey, this individual, everybody had 30 seconds of rest, 60 seconds of rest in between trials. And one of the strength coaches like, okay, outside of the methodologies being a little bit blurry because it's harder in season to collect data with athletes based off of the demands or the training demands of getting these athletes to do the testing because they're not sedentary individuals or whoever you're getting your subjects from outside of the standardization of methodologies. What would you say then needs to get cleaned up from doing sports science better for team sport athletes and team sport coaches before we get into the RSI DRI stuff. So that's a great question and I would say just to clarify on that. So look, I think standardizing your methodology from a research side of things is extremely important, right? Huge. Huge. Everybody else can try to repeat it. Of course, of course. Yeah. So from a research side of things and gaining insights and coming up with findings standardizing the methods is is is paramount, right? When it comes to how we apply this in the practical space. As you pointed out, there's going to be there's going to be a sludge factor, right? There's going to be there's going to be you know athletes who are jumping around and goofing off over here in the corner and you're trying to you know test they were trying to get them all the same amount of rest, but you're trying to follow the study as if it was a recipe. But really the if we're just talking about some some hypothetical example here of just some some study or group of studies that have this outlined methodology and you're following it like a recipe. That that might not necessarily be the best practice, right? You're just because the the role of the study, the role of that group of studies is to give you sort of broad general recommendations through which you can take that and then apply it to your individual scenario. Okay, so when you're reading so what I guess I'm gathering maybe this is new for me and maybe other strength coaches too, but it's not like hey, this study did xyz follow this, you need to do it that exact same way that strength coaches don't have to do it exactly like that. Yeah, and so in a lot of in a lot of cases, yeah, that's that is what I'm saying. And I think just to jump ahead a little bit because we know we're going to talk about RSI and DRI. One of the huge problems with RSI reactor strength index is that even in the studies, there's no standardization. Even in the studies, it doesn't RSI doesn't account for the entire mechanical task, right? It doesn't account for an incoming drop if there is one. It's quantified in different ways. You have your con your your jump high or contact time or you have aerial time over contact time. You said these these different these different ways and then you have all these coaches because they recognize intuitively, not necessarily with the scientific and mathematical lens, they recognize intuitively that RSI is a is a very limited flawed metric. And so they've in their own practice have implemented their own individual strategies for how they can overcome some of our size limitations. So RSI needs a replacement that doesn't have those same limitations that anybody can use with their own individual system and set up in limitations of their of of their scenario of their actual constraints with their team or their facilities. That then with a need of replacement metric that's immune to any of those potential problems. Okay, so let's double let's double down for me and then hopefully other people because with with RSI like you said, it's going to be calculated. You know, people could do the multi rebound jump. They could do the drop jump where it's ground contact time on the bottom, jump height on the type or jump hot on time or aerial time and air on top. So you have your two different ways. It could be the multi rebound and you're looking at multiple of those and you've talked extensively on social media where that one is either vector list or not vector list and this one it like. So let's let's let's dive in and let's zoom in on this. Dimensions. Dimension list. So it was just think broadly let's kind of zoom out and think about I'm going to adjust my light just a little bit here. If we think just broadly from a science standpoint physical quantities, right? All physical foot of all physical quantities, you know, velocity acceleration, force, you know, body weight. All these all these things can be all physical quantities in science are boiled down to three fundamental dimensions. We call them dimensions or qualities. So quantities versus qualities. So think about mass and these quality, these qualities are mass length and time. Okay, those are the three fundamental qualities in science. So think about, let's think about velocity in quantities. The velocity can have different quantities. So if the if if the if the athlete is sprinting at a certain velocity, I can quantify that as 10 meters per second or kilometers per hour. So those are two different quantities that are describing the same event, the same quality. And that quality is the is the variable is velocity. Right. So when you take velocity, you're describing a length over a time, length and time. So you're two fundamental qualities associated with velocity. And mass is just mass. Body weight is another one that can be boiled down to its fundamental dimensions. Body weight is the interaction of your between your body mass and the force of gravity. So when you boil down to its to its fundamental dimensions, you get an acceleration, which is length times squared. Right. So I'm just I'm this is a lot. But I'm kind of I'm just trying to outline that any physical quan it's a length times squared, but then also mass. So those fundamental fundamental dimensions are mass length and time, right? So for any physical quality, any physical phenomenon, any measure in science boils down to those three, right? So the reason we boil them, boil them down to those three dimensions is so that we can do the reality check for whether a metric is. You know how to say before you get there, how do those three get boiled down or those three kind of like primary colors that, you know, blew your thinking broken down like red can't get broken down in yellow. Correct. So they're mass mass length and time are your primary colors. That's that's a pretty good way to think about it. I'm there like bro, it's took a bridge water back in the day, had the revolution helmets, not a ton of padding. So you got a lot of ad trauma right here. We're we're keeping it simple strength coach. Perfect. So we got our three we have our three boil down keep going. Yeah, so so your product you're perfect. So you're your blue red yellow primary colors, math length time are your primary building blocks for other quantities and measures in science, right? Got it. So the reason why we do this is called the dimensional analysis. We take any you can take any variable metric, boil it down to its fundamental qualities to see what is it representing. So going back to velocity velocity is length divided by time, right? And there's many different ways there's many different ways to quantify velocity because you have different units of velocity. Me just for second kilometers per hour. Yeah, even if the object's moving at the same velocity, you can throw different quantities at it to describe it, right? But at the end of the day, it's still a length over time. Yep. So we do this as a reality check for any variable to assess whether it's actually giving us what we think it's giving us. And so can we move on to RSI really quick? Oh, yeah. So how this relates to something like RSI is we take the way that it's most commonly quantified. I mean, even though it's people quantify it different ways. Unfortunately, if you take the one the way that it's most most commonly quantified, it's jump height divided by contact time. So it's the time it's the height that you achieve in your jump. And you know, divided by the time you spent pushing on the ground for the jump. So I'll let you take a stab at it. What do you think? What are the units for that? That would be, I believe it was. So we're talking jump jump height over jump height over. So that's typically going to be measured in meters per second. Because it's a height, you know, and usually measured in meters over time. But I mean, technically you could say it could be. Feet over. over milliseconds, just because of, you know, the shortness of ground contact time within the RSI world. And one coach that talked about it really well was I like what Wilret tell said where, you know, yes, if you're getting athletes to jump off the ground super fast, but they're not actually achieving a jump height that is close to what, like, their true maxes. Now, that's where you're, it's like, I like where he said, I think he said 80% or 35%. Huck in dynamic and strength coach networks trusted provider for force plates and for handheld dinometers. Not only am I using it now in the private sector at Goldfinch, I was utilizing this software when I was back at Towson University. You're able to transport the plates because I've taken them from our private sector facility to our other locations, also been able to take it from our private in-person location to the high school down the road to do some testing with athletes right then and there. You're able to pair your true strength with the striking difference machine. The people at Huck and our fantastic, the technology is second to none. You have to learn more about Huck and dynamic in the link down below. I think it's this exercise could be kind of used in that drop jump analysis of Verkashinsky stuff, but so that's my version of it right there. So, yeah, so you, yeah, you pointed it out exactly. It's, it's typically it's a meters per second or feet by milliseconds. So different quantities, but what are the fundamental qualities? What are the dimensions of that? It's a height in the time, right? It's a length in a time. So length per time. That's a velocity unit. That's a velocity unit, but our size is not a velocity. In fact, we're describing a length kind of time in a time that happened to you. Yeah, yeah, yeah, jumping fast. Yeah, it's so it's mathematically that number should represent a velocity, but it's not a velocity. In fact, the length and time you're describing happened. They occur at completely different moments within the, within the task itself. So we're not talking about a velocity here. We're just talking about a mathematically incoherent variable. So right off the, right off the top, our side doesn't, doesn't pass that first reality test that we, that we use for a metric in science. It doesn't, it doesn't even pass that first checkpoint, right? To say nothing else about the mechanical issues, but we can, we can sit with that for a second. If you have any questions about, uh, I guess my, I think some strength coaches might be thinking, like, okay, that sounds great and well, Lance, but who really gives it a hoot because I'm not in a lab. I'm working with athletes. They want to get faster. They understand, hey, get off the ground really fast, jump really high. They understand that the number can get bigger by jumping faster off the ground or jumping higher. And they understand that when they're on the field, they have short ground contact times when they're sprinting. So it applies to them, sure, mathematically, that doesn't make sense. But I'm a strength coach. I don't really care because it's just a number and I'm continuing to get my athletes that right. And then this, this is where it becomes really important because this is a symptom now of the scientific illiteracy issue in the field is that there's not a recognition that when you decouple the, the, the metric from what's actually happening, the task, the mechanics, then it becomes non-interpretable. So RSI really, it doesn't behave even in terms of the scope of how the jump high and contact time interact with each other. It's not, you've decoupled it from the actual event, the actual task. So then when you see differences in numbers, you don't actually know where that difference is coming from. It doesn't, so the, so it being mathematically incoherent means that it's mechanically non-interpretable. But what if somebody is listening to you and just said, but okay, sure, I can see that somebody had a 3.4 when they jumped 30 inches and they were on the ground, 0.25 seconds and they were a 2.9 when they jumped the same height and they were on the ground for 0.35 seconds. So I can see that they were less explosive, less fast off the ground because they were on the ground longer and then that could cause them to pull on the thread and say, okay, why were they on the ground longer? Was it a higher box that they jumped dropped from? Was it just a bad rep where they neurologically fatigued? So then could, what if a shrinkage said that to you where they're like, oh, now it is interpretable? Well, because now they're going off of a test that they've invented and that is that we can't possibly compare their test to someone else's test or even if they had another coach who was trying to test reactivity in their, within their own facility, like they're saying, so you pointed out, okay, did this happen because I jumped from a larger box? Well, RSI can't even tell you that. RSI doesn't even include the fact that you jumped from a box or how to all the box was. It doesn't, it ignores the mechanical demand of having to accelerate the center mass against gravity. So if you have somebody jumping from or dropping from a 50 centimeter box, someone dropping from a 10 centimeter box, if they spend the same time and achieve the same height, they're going to have the same RSI score. But would you tell me that those two people executed the same example? Way more impressive for the higher drop. So DRI takes drop height into account. It does. And so, yeah, so with RSI, we'll stick with those two hypothetical individuals. So they both achieve the same jump height. They both achieve the same contact time, but one drop from a 50 centimeter drop in one drop from a 10 centimeter drop. I'm going to write this down to make my life easier. So we have 50 centimeters. We got 15 centimeters. Let's say they both jumped 30 inches and let's say they both did it in 0.15 seconds. Got it. Yeah, let's weigh more impressive to do that at 50 centimeters. And let's say this person weighed 200 pounds. Right. And let's also keep our units consistent. So let's stick with, let's stick with centimeters or let's stick with meters. Okay. So we're going to go 50 centimeters, 50 centimeters. They jumped. We're also going to say 50 centimeters. And they were on the ground for 15 milliseconds. And this person weighed 100 kilograms. Sure. Now the drop, the drop box, the height of the incoming drop for one athlete would be, let's call it 50 centimeters. And then for athlete B, 10 centimeters. Okay. So how would you calculate RSI from that? I would still just do the 50 over 15. But I would call it RSI 50 drop or RSI 10 drop. Like I would have it categorize that way. Right. So then how, how can, how can that be tracked over time? How can that be compared to another protocol? It can't. I would just be able to track. So if I was going to test it, I would just keep, I would say, okay, this is going to be what we choose because this is where we work and we're going to choose 30 inches is our standard. When we test it and we report and we track progress over time, we're going to stick with a 30 centimeter drop. We're going to train it in training below the demands above the demands. So a lower drop height, a higher drop height to then hopefully improve this output in the same way that we'll train above the demands below the demands for the conditioning aspect, the sprinting aspect, and that's how I would do it. Okay. So now what you've done is you've taken a highly limited metric. You've, because it's highly limited and it's mechanically flawed or it's mathematically, incoherent and mechanically non-interpretable. Now you've, you've had to, you've had to invent your own testing protocol that you, that's unique to you, that you categorize things. You have, you have an RSI, you have a different RSI for this and a different RSI for that because they're, they've, it's been decoupled from the actual mechanical task. And then also just the way the mathematics are set up in RSI, depending on where you fall in the contact time, had jump height, spectrum, your RSI is going to treat those two things completely different. So depending if you, if you spend a little bit more time on the ground versus have a really stiff landing, RSI treats those two things as completely different mechanical tasks, whereas DRI, it treats things much more like a continuum because it should be a continuum. The way you, the, the way you manipulate time on the ground and impulse in the way you accelerate your body against gravity, there's a whole, there's a whole continuum, a whole spectrum of mechanical solutions within, within that, that frame. RSI just because, because of the way it's set up with the jump height over the contact time and they're not even related to each other in terms of what, when they happen during the task. Now, now you, you, you, again, the, the issue, the issue with the, the mathematics being incoherent, the dimensions being incoherent, is that it's, it's not actually telling you anything. It's, it cannot possibly describe what's happening mechanically. One of some, but what if anybody's listening to us right now and they're like, okay, but we're not like, there's going to be inter and intra, rater reliability issues on the drop itself because you could have, like you could try to standardize it as much as you want, but you're not going to get every single athlete to not slightly lower off of it. Powerlift is strength coach networks, trust to provide it for exercise equipment made here in the USA, right down the road in the state of Iowa. Powerlift has the ability to customize whatever you need in your room, regardless of of the sector of strength conditioning. If you need a massive big room they have the ability to help you with that. If you're confined with space and you need to get creative, their reps are able to help you get what you need done and being able to get any customizations that you or your organization want with your logo on the equipment. Click the link down below to learn more about Powerlift. And if you have any questions about them, please feel free to reach out to us. Jumping off of it. So does DRI take into account? Okay. We told the athlete to step off the box as if they were stepping off of a, they're a pirate, you know, walk the plank type deal. Don't drop off. Don't lower off. How do you standardize for that? Because there's almost no way to truly standardize for that. Sure. Well, so that's a good question. And it actually you can standardize for it. It depends on how careful you are with your actual test. So this is where, you know, you maybe do have to kind of follow the recipe, but only in the sense that if we're doing this on a force plate or if we're doing it on, yeah, if we're doing on a force plate or if we're doing with high speed video to get aerial time to drop, then wherever time it takes for them to drop, there's a known relationship between time to get to the ground and velocity and there. That's what you're all right. DRI takes time that you're leaving the ground from said drop height until you hit ground. So let's die. Like what is the DRI though? Let's just let's dive into that. Let's drop in this thing up. So let me, let me just, let me just first kind of clarify that point is if you just say, oh, all my athletes dropped from 30 centimeters and I'm okay. Fine. You're, then you're going to have a little bit of that error, right? You're just kind of assuming that they all went from the drop at the same exact time, right? But if you're more careful and you put a little bit more effort into actually figuring out, you know, did somebody kind of like do a little bit of an arc in there, stepping off the box and because okay, fine, fine. Then maybe the time it took for them to get to the ground is reflective of like, okay, they dropped from 33 centimeters or, you know, this individual dropped from 40 centimeters because he jumped off the box a little bit, right? So we can still, we can still account for whatever incoming velocity they have from coming from the drop, whereas RSI doesn't even attempt to. How does it do that then? What? How does it take into account that, like I said? Oh, yeah. Okay. So now I'm going to go with you. Because then within the, the finiteness of it, like, okay, this one was 31 centimeters. It was 29 centimeters. How intricate does it get? How is it calculated? Let's, to, to quote Matt Jordan. Let's chew the fat on this bad boy. Sure. Sure. So DRI mathematically, the, the equation is jump height plus drop height. Jump height plus or drop height. So whatever height you jumped to, plus whatever height you dropped from. Okay. So you're, wait, it's the sum now of the two displacements. So it's the total vertical displacement demand. Okay. Gotcha. So I dropped, so in this one case, I dropped from 50 centimeters and I jumped 50 centimeters. That's 100 versus I dropped from 10 and I dropped 50. Now we're at 60. Got it? It's, it's one because it's in, it should be in meters. Oh, sorry. One versus point six. Okay. Right. Okay. So it's one versus point six with you. Yep. Divided by now, I, I, I might know the answer to this, but if anybody remembers from a high school physics kinematic equations, it's divided by GT squared. So gravity times, times squared contact time. Contact time. So the gravity 9.81. Yeah. I remember the 9.81. I actually do remember it kind of like high times the contact time squared. Whatever your contact time was. So in this case, it was 15 point, point 1, 5. And so this, so point 1, 5 squared. Yep. So let's do that math. So, so GT squared in this case, I've typed those down. So what was the contact time we said? So that we were saying the contact time was point one, five. So point one, five times itself times 9.18. So that gives me point eight one. What's up? 9.81. Oh, 9.81. Not one eight. That's like dyslexia coming in. Point, point 221. We'll round up. So that's in your denominator. Yep. 221. We'll round up. So that's on the bottom. And then up top, we have a one in one of the cases, or we have a point six. So the first thing I do, one, two, one, they have a DRI of 4.52. Yep. Versus point six divided by point 221. They have a DRI of 271. Okay. So, same performance, leave from, from the time they hit the ground to the jump, same performance, but they came in from different, from different drop height. This is kind of like the Sayers equation, taking body weight into equation for your vertical jump. No. We're not taking body weight into a problem. Sorry, I know we're not taking body weight into occasion, but we're allowing for us to compare a heavy person that weighs 300 pounds jumping 10, 20 inches versus somebody that weighs 250 pounds jumping 25 inches. We can compare apples to apples now, which was kind of the big thing that football strength coaches were saying, Hey, I know that guy only jumped 24 inches, but he weighs 330 pounds. That's just as impressive as a 200 pound guy that jumped 36 inches. Sure. Yeah. Yeah. You can make the analogy. Yeah. Yeah. Okay. So now we're finding ways to actually reward, but more mechanically, Shreddy was task any strength coach that's listening to this, they could say, Okay, but at the same time, we're setting it to be 30 in, you know, the 50 centimeter drop, 0.5, 0.5 meter drop. But what if that athlete again, wasn't like, are we just going to accept that as a standard error and kind of a limitation, a, what would that be? A type one limitation of this understanding that, Hey, yes, every athlete, we instructed them to step off a certain way. Nothing is perfect. We taught them and, and it's close as we could. We told them not to jump off, not to lower off, but that's as close as we can get without doing video analysis of like, well, technically it was 50 set 0.5, but they dropped a little bit or they jumped a little bit. Yes, you can absolutely just take it for granted that your athletes all executed the test the same way in terms of jumping, stepping off the box. You can absolutely take that for granted, but if you're somebody who doesn't want to take that for granted, you have an option for figuring out what their exact drop height is. How? Just doing the timing. So the time to hit the ground from the time you leave the box, there's a known relationship. You can get terminal velocity of the time. The time the time it takes to actually hit the ground, there's a kinematic relationship between the height that you fell from and the time it took for you to get hit the ground. How can you figure out? So let's just say, again, we're 0.5, I'm standing at a 0.5 meter height box. You tell me to jump. I'm on my Hawkins force plates. Are you like, because if you could hit the play button, the screen flashes, what if I delayed a little bit and that would be a lag in the time that it would show? How do we how do we accurately know? My drop time from the box onto said Hawkins plates jumping in the air and subsequently landing again, because you know the frame that you leave the box. So we're videoing this. You can do it again. As an option, you can hit you. Okay. That's what I was about to say. And that's just not scalable within the team. No, certainly not. No, but what is scalable, whenever you want to scale something, you have to make some sacrifices. And so some of the sacrifices you can make are just make small assumptions. We talked about assumptions in science. You have to make assumptions when you model anything, right? Because if you don't, if you don't, if you can try to count for every little thing all the time, but that's just not possible because if you're, if you're still trying to account for, you know, every mundane little detail, you won't get anything done. You won't make any progress. At a certain point, you have to just measure something. And in order to make any type of measurement, you do have to bake in some assumptions. Like, like the fact that, okay, I assume that this tool that I'm using is measuring what it should be measuring. I am assuming that it's calibrated because it calibrated it earlier today or calibrated yesterday. You kind of, you have to stop and make some assumptions. So an assumption that a coach can make when executing these tests is that, okay, let's just, it's a 30 centimeter box. Let's just, that's the 30 centimeter, that's the, that's the drop height. Now, we're just going to say that that's the drop height for everybody, even though somebody may have arched a little bit to 32 centimeters. At the end of the day, if you crunch those numbers, it's not going to make a huge difference with their DRI score, right? If you're a 30 centimeter box, but somebody did a little bit of a, like a little bit of a high step and they dropped from 32 or 33 centimeters, you're not going to get, you're not going to get a big difference in your DRI score. So it's going to be inconsequential. Now, is, is there a way to then take body weight into account with all, like, okay, we got DRI, we've, we've helped solve one step of the problem. What if someone's DRI starts to go down over time and I'm talking about a kid that came in in at tight end, he moves to offensive line, he gets heavier, his drop height stays the same, but his jump height starts to decrease because he's weighs more. How do we then take body weight into account, tell about those coaches? So it's one of those things where you kind of in a way we already are taking body weight into account because it's about the athlete's ability to accelerate their center of mass against gravity. So the vertical displacement demand versus in the denominator. Vitruv is the trusted VBT source for strength coach network and I have been utilizing this for years at Goldfinch and I'm going to continue to utilize it because the great price for the encoder as well as the accuracy with the data. Whether I'm measuring average peak or any other metric if I want to include range of motion, fatigue, loss, deer, and the set, interest set, whatever it is, I can trust Vitruv and they are continuing to push the needle and continuing to educate coaches on best practices within the VBT world. Not only do they live in that VBT world, but now they've come out with their new hub and if you want to learn more about the hub and how it can help you with all of your athletes that you are working with as we are starting to do this at Goldfinch for our middle school all the way up to college athletes, check them out in the link down below. Now we're talking about the actual kinematic relationship of the center of mass movie against gravity. The body mass is already thinking what I'm just saying. It's going to be harder when like, okay, when I was at Bridgewater, I wait, I came in at 225, I played at 300 pounds. So if I'm stepping off that 30 centimeter box as a true freshman, yes, I'm going to get stronger. So my jump height might not have been that high because I was a weak incoming freshman. My ground contact time might have been long. So like, again, those are all some kind of hypothesis. And I guess that's where you just have to kind of run the experiment over time and see it. But my question would be if you're taking, you know, let's take it to the NFL. You're getting a kid who's a, you know, a Tristan Weriff's coming out of Iowa. He's really, really strong. He's already these things. He's at a constant body weight. Maybe the organization wants him to gain more weight. He gains more weight. Now they could be like, oh, jeesh, your DRI didn't improve like you're right. Like, but he did get heavier. So I guess that would be like, okay, is there a next step of how do we, but he got the athletic in other words. Yeah. Like he's, he's not jumping as high. His ground contact might have gone down a little bit, but it's a bigger human being doing said task. That's more impressive. Well, then, then this is one of the scenarios where we have to be very honest about what DRI is even trying to do here because it's, it's a tool in someone's toolbox, right? Where it's, it's, it's, I, I basically, I've, I've taken away your butter knife and given you a steak knife because you're trying to cut a steak, right? But you're, you're, your, your diet doesn't consist of only steak, I assume. So it's, I'm taking away a bad tool and giving you a better one, but that tool still exists within the context of all the other things that you're doing to assess your athletes and athleticism within the context of their sport. No one would, because no one would ever even look at RSI and say that RSI was the end all be all for determining how athletic my, my guys are, right? All we're, all we're doing here is, is saying, okay, RSI is not, not giving you what you think it's giving you DRI is going to give you a clearer picture into your athletes reactivity when performing these tests. So then, but let's not overstate what the, what the test is actually giving you. Does that make sense? Yeah. And what if a straight, okay, two questions and why contact time squared is it because you're taking jump height and you're taking two heights and that's why you're squaring it? Exactly. Okay. Yeah. Cause you have two, cause you have two velocities and incoming velocity and outgoing velocity. And so if we're going to actually link this, because RSI, again, is decoupled from the actual physical task. It is how, how, so again, just because, again, forgive my ignorance. What, how is it decoupled? Because you have the jump height and the contact time that they happen at two completely different moments in the task. So you can't, and so it's other than the units are now velocity units, but it's, but velocity is a rate of a change of position. That's not what RSI is giving you. It's just giving you a very kind of like overly reduction, reductivist jump high or over contact time. Let's call it a day. But then there's, there's severe interpretation limit issues with that. So now DRI is taking the total vertical displacement demand, incoming, outgoing, divided by gravity times squared contact time, which you correctly pointed out is because you have two distances. And so we're linking this now to the kinematics, the actual, the actual interaction between the center mass motion and acceleration due to gravity. Next question. If a strength coach or practitioners listening and they're like, okay, well, I'm never going to be changing the drop height. I'm always going to do 30 because that's what we do. Do they then need like, they're just going to keep it 30 forever athletes get heavier over time, but they're just like, hey, we drop from 30. I never have to worry about that. So I'm going to stick with RSI. Well, then there's still, they're still dealing with a metric that doesn't treat jump high and contact time properly. Because now RSI is still, it's rewarding artificially short contact times where you don't have sufficient jump height after that. So now if we look at actually how the how the issues, or sorry, how the how the, the, if we look at the issue of how each metric handles jump height and contact time, DRI is the better metric RSI. So if you, if there's a strength coach, you, I've been using RSI for 20 years. It's just what I'm going to keep doing. And I don't need to account for an incoming thing, incoming drop height because I keep drop height constant. Okay, fine. But you're still now working with a metric that is treating contact time and jump height and properly. How is it doing that? Because if you don't have, if you don't have any meaningful vertical displacement, any meaningful jump height after your contact time, you can gain the RSI test with having artificially short contact times and keep your RSI scores inflated. So now you're really, now you're really not serving your athletes or or or or assessing what the true reactivity is their ability to overcome the mechanical demand itself. You, you have a test that can be gained. You could gain this one too then. No, you still have to jump high, right? Like you still have to put out and you're going to be on the ground a little bit longer to jump high, right? I think we'd all agree. Like there, there is that fine line between okay, too short. I can't jump as high. Now I'm on the ground for two like so you have to find that sweet spot. I guess that this is forcing you to find the sweet spot. DRI will, DRI will, uh, will I will punish you for trying to gain it? I think what then you like, I think everything that I've seen you putting out on social, uh, it looked way more complicated than this right here. Like this is actually like you can actually plug and play this. This is how you drop from how high you jumped and the, like it's the same metric, the same numbers that everybody has. Yep. It just looks so much more complicated. Yeah, you know what? What is this? Yeah. So, so here's the thing about that Justin. That's all, that's very intentional. I'm being very intentional about that because so now we can have this conversation and we can simplify the concept. But what I'm on social media and I'm introducing this. Now it's because, because there's been so many people in the past who have who've attempted to improve RSI and they've come up. Yeah, I know. Yeah, there's been, there's been, like, you know, just like practitioners who have recognized that there's a, there's limitations to RSI. So they've, they've come up with their own like, um, their own variations that they think are improvements without recognizing the full scope of RSI's issues. So if, if we're going to have a, a true replacement for RSI, it needs to be handled with the utmost rigor scientifically, mathematically. So that was my whole project here was to, to, to actually work through the mathematics, find something that is mathematical, inherent, mechanically interpretable, but still relies on the same simple measures that Strength Coaches love about RSI. Oh, I can just get a jump height and a contact time or a flight time and a contact time. And so that's why RSI is so easy for me in my, my large, my large, you know, team where I'm, I'm having a bunch of athletes coming through. So yeah, of course, any replacement for DIP or RSI would have to be as simple to collect the data for. 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Now, not only are you going to be able to save time, but you're going to be able to save money with this great product and you have a valid and reliable product that has run through countless different articles as you continue to see online being published with the accuracy of this information. So if you want to learn more about DASHER, click the link down below to be able to go to their website and learn more about them. It is. Okay, good because I'm like, this seems so like, I'll be. excited for this podcast because like he's a smart dude I just want to understand what he's talking about. Yeah, yeah, so when you see the sort of the complex topics being shared on social media, it's because I'm trying to show you guys how bulletproof this actually is. And so challenge me, but here it is. So I don't want there to be anywhere for someone to go hide and say, oh, our side is still better. It's not. And I'm going to show you why it's not better. But then yeah, once I convinced you that DRI is better than RSI, then let's let's really talk about how simple it is. It is really simple to implement. You can it's information that these coaches are already collecting correct for RSI. Correct. So then what's the okay, so this gets changed. Why? Why make such a big push that this is important to make a change? Say that again. So like you've you know, anybody that's been listening to us over the last just under an hour. And they're like, okay, cool. You know what? You've convinced me. I need to start changing this. Why did you? I don't know. I don't know how long you spent trying to figure this out. Shout out to you for that. Second of all, why then? Like, okay, you did all that. And now it's like, what was the reason behind like one on earth? Made you think of this because I'll tell you what, this was nowhere near on my lens of things to talk about with you. Yes. Again, I guess I think of some other random things. So yeah, that's my question of like, why did you think about this and why spend the time and energy to educate coaches on it? Sure. Yeah. So I'll try to I'll try to answer all of that. But because the why is because now I'm hopefully giving a giving coaches and practitioners a metric that is doing what RSI has been pretending to do this entire time. So now DRI is giving coaches an actual way to assess their reactivity of their athletes during drop jump tasks or locomotion tasks or whatever have you, whatever variations of their reactivity tests they have. DRI is now giving them a metric that is fulfilling the promises that RSI was making this entire time but was not delivering on. So is that. And then the sort of motivations for even tackling this is a problem is number one, I identified a need not necessarily based on my own need but the needs of practitioners. I have a network of practitioners as you do and as you know about me who use RSI who have recognized independently from even my input that RSI has problems and have attempted to improve it either by adding constraints to their tests which you pointed out. Okay. If I can add this and just control for this and keep it constant or require my athletes to reach a certain jump. I need to know what your max jump height is to then be like, Hey, okay, that jump height divided by ground contact time, that jump was not 85% or higher. You're gaming this. You're cheating the test. Yeah. And it's also it's just one of those things where it's RSI is kind of pretending to measure reactivity but it's forcing coaches to add their own rules. These not to these tests that can't possibly be standardized and it's so then we have all this normative data for RSI across athletes and from coaches have collected it but they all measured it completely different way. Which is yeah, so you can't possibly compare that. No, that's the whole point. Yeah, yeah, yeah. You were data is the only data that matters and too many people get so obsessed about what the normative data says but just like you said right there, you have no idea how it was collected. Exactly. You can't trust it. So, yeah, so this is this is but this is a symptom of the fact that RSI is under delivering on its promise and so so then coaches are having to they're they're handed this this thing that they they think it's giving them what they what they want. A measure of reactivity but it's not and so intuitively they recognize the limitation and they have to create their own test within their system that it's incomparable to other systems. And to though because you like we still can't take like that's where CrossFit has done an amazing job making things scalable and trustworthy because you have to film certain things to get things graded. So that way it's not just a number and this is something that my former assistant Kyle Hashimoto who's at UCLA baseball talked about where we bought this awful system called the Tracer at Towson. The people in charge bought these three movement capture systems that were absolute trash. If anybody has Tracer and it's better than what I had shout out to you bless your soul because I it was awful that we had the minute they showed up after they showed up not to do a demo. They showed up after we had already paid for three of these things and we're like you can't like it's faulty here. It's not doing this. It can't film me wearing black pants on a black floor. Our athletes get team issued black pants. Our floor is black. Why did we buy this? I don't remember where I was going with all of that. But oh so we were supposed to be told like hey this is going to replace any movement screens and so and so is just going to be able to give you a number and my Kyle was like we can't trust a number if I didn't know how the number was like originally calculated or how it was scored. And that is to me why when I hear like oh this athlete jumped this or their their 1 RM was this anytime I hear an athlete come in I instantly take 10% off because I'm like I don't know what your gap was. I don't know if there was hands on the bar. And that's part of the reason why with the normative data stuff it's like the only data that you can really trust is yours because that's the like we can standardize it as best as we can but somebody could be cooking the books saying like oh they dropped from this height and this was their jump their jump height because they could be you know you could be getting their their DRI because somebody is calculating it based off their Pyle Matt instead of something else. Right yeah and that's the thing is is just say hey here's my Pyle Matt DRI my force plate DRI right right right and all right. All right does that make it does that decouple it to use your words. So if I'm qualifying it by saying this is my DRI on a Pyle Matt versus my DRI on force plates does that is that just qualifying it saying hey these are two different devices. Yeah D coupling it I'm just describing what device was measuring it because we understand how each of them calculate step metrics. Yeah so they should all calculate them the same way based on the same physical phenomenon but each tool is going to have its own sensitivity its own accuracy. So doing doing doing RSI or sorry DRI on a on force plate is going to give you it's the gold standard it's going to give you it's going to give you more accuracy something like a Pyle Matt yeah like a Pyle Matt that it's a great tool it's affordable it's cheaper it's I would argue a better tool for the practitioner because force plates you need you it's in there so expensive they're these are research quality tools that are so expensive yearly subscriptions but these the average practitioner doesn't fully know how to use a force plate and they rely on these metrics that these these companies spit out and give them and they trust the numbers that they actually means something meaning that they're give you anything meaningful when with a lot of times they really don't. 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So I think unfortunately the increase access and availability of lab grade equipment is it's it's it's an aspect of the field nowadays that I think is actually counterproductive. I'm glad that we had this conversation about DRI because now I do I'm like I don't understand this at all but now it makes way more sense. Good yeah because yeah no the sharing the complexity of the the mathematics behind it how complex it can be with with doing a rigorous analysis is very intentional about that just again just to demonstrate the bulletproof aspect of the R.I. compared to RSI. What okay let's think into the future where are the flaws within it like you said it's bulletproof where where because whoever first came up with RSI thought it was they thought it was bulletproof in 10 years who is going to be trying to poke a hole in DRI and what would they do what would they say. I think that's a really funny question I do think the I have some insight into how RSI came to be and who but I don't want to I don't want to be disparaging any sense but I don't think that I don't think that they put a whole lot of thought into bulletproofing as a metric I think they just went with a simple jump I or contact time called it today and then it's propagated across the field. and you can find it everywhere. And it's being used because coaches, they have a need for assessing their athletes' reactivity. And so this is my effort to do my part to make their lives better by offering a metric that actually delivers on the promises that our side was making, but was not fulfilling. Now you said identify flaws and limitations. - Yeah, like what were somebody trying to pick you apart in 10 years, what do they say? - They are, well they're all ready trying to do that. - Oh yeah, I'm getting resistance, but you know I welcome it, right? Because the novel thing, and it's really about educating. It's educating and saying, here's this new thing that is, it doesn't suffer from all the same limitations that our side does, but it's gonna be a significant improvement for your system to be beginning to implement it. But again, as I kind of alluded to earlier, it's really important that we don't overstate what DRI is giving us, right? It's really just, it's a simple measure of reactivity. And if we can define reactivity, simply as you're saying, the athlete's ability to reverse an incoming velocity into an outgoing velocity. I think that's a decent working definition of reactivity. I'm sure we could add some things to that, but as far as just a simple definition, I think that's what we're trying to assess when we're using RSI or DRI. So DRI is just a better test of reactivity. It's not gonna give you anything about your eccentric or concentric impulse during the contact phase. It just treats the contact phase. It does, it's just one thing. - Yeah, when you do it in on force plates, you can get that number. - Yeah, you can get the number, but DRI is not gonna do anything with it. - No, no, no, no. But you can look into it. - Yeah, you can absolutely, you can get that information and you can apply it to your site. So again, I mean, we're talking about DRI being a tool. It's a Phillips screwdriver within your garage. It's not the Ferrari in your garage. It's the athlete. - That's the athlete. - Yeah, right. It's one of the tools that you use to work on your larger project. - That was, this was very insightful for me. - In fact, in fact, I'm probably gonna have to do a post that reflects that message soon. Just again, it's not about overstating DRI as, oh, this is the thing you should focus on. I would never even say that. This is not even my full, my bread and butter. I'm into locomotion science, sprinting, the mechanical relationship between movement, mechanics, and metabolism at the whole body level, right? So this is just something that I, it's almost like a pet project where I recognize a need in the field for a better metric. And this is me offering the solution that I think will improve the systems of many practitioners. Should they implement it? - What else do you then work on? So this kind of took up, let's say, a bulk of your time and your interest. What do you dive into now? - So right now, since I think DRI's been pretty well received, in fact, there's a number of platforms that are already incorporating it, apps and tech that are actually starting to incorporate DRI, which is exciting to say. But since I offer this DRI metric, I think it's incumbent upon me now to begin working on offering some normative values. So I think that's one of the nearer projects is to get some normative values from across athletes and abilities. So that's probably becoming a front burner item. I'm also working on four sprint acceleration papers right now, just probing the mechanical limitations of the human's ability and other animals too, ability to accelerate. And then I'm collaborating with some individuals on a 40-yard dash sprint acceleration paper. So that was the idea. I'm the PI on that. So I'm actually going to probably be using a lot of the BSU football players. - Let's go. - What has been, what do you see really wrong right now in the sprint world? I'll tell you what everybody's doing. Is everybody's doing hip flexor health stuff. If you look on social media, everybody is all about like seated hip flexor stuff or like one leg hip flexor, like what do you see that is, let's identify something that's wrong and then let's give them something that's better, much like you did with DRI. - Yeah, so like the hip flexor stuff, I think that stuff's good. I think it's valuable. I think especially for the health of the athlete, because if the athlete is the Ferrari, I mean, sometimes you gotta make sure the tires are staying aired up, right? You know, making sure the oil's not getting too low. So yeah, things like that, the sort of regular housekeeping, taking care of the hip flexors. That's just one of the long list of things that you want to focus on. So things that are being, that are kind of wrong in the sprint community, I would say just as an example, it really comes down to how performance is being quantified. So I'd say the most, the most pervasive issue with quantifying sprint performance is really the stuff surrounding the force velocity power profiling in sprintors. So that's the one that really gets my goat the most. 'Cause now, in words, it's gonna sound really rich coming from me, but it really is an over-complication, over-complication, it's really over-complicating sprint performance assessment. - But you actually just said, you're purposely trying to make it sound, but like you said, hey, I'm trying to make it sound really scientific and really well philosophically created, but it's simple to be able to assess and apply. - Correct. - So you weren't trying to over-complicate things, you're trying to make it simple, but make it understand like, hey, I understand, it's like when you're explaining something to a kid, I understand the complex, but I'm trying to make you understand that it's not that hard. - Correct. - Now what you're saying is, you're seeing people take something that's really simple, try to make it sound complicated to get-- - It's the opposite, exactly. It's the exact opposite, and I'll explain. So when you talk about the main issue comes with, the power part of it, and how power is being calculated, 'cause power is the product of force and velocity. So you're taking this force velocity phenomenon, which is a real phenomenon with isolated muscles and muscle fibers, it's a lab-based phenomenon in muscles, and it's real. So the trade-off between the tension that a muscle is able to produce with its shortening velocity. So at faster shortening velocities, the muscle cannot develop tension. And then at zero shortening velocity, isometric, the muscle is developing its maximum tension. - Yep. - Right? So that is the force velocity relationship of muscle. You have a load and movement velocity relationship as well. So the heavier an object is, the slower you're gonna be moving it when you're going with full effort, right? So you can move a lighter object more quickly, a heavier object more slowly, just by virtue of those mechanics. The relationship, they're related, but they're different. Now, if you try to take this force velocity relationship and apply it to whole body movement, particularly in sprinting, what you're now saying is that your power at top speed is basically zero, because you have no, you have no net force because the horizontal breaking effort full force's forces are now evened out, but you have all this velocity, but if you have all this velocity and no net force, you have no power at top speed, right? And then if you, conversely, if you at the start of the sprint, where you have very low or no velocity, but a lot of horizontal force, you still have no power. So you have, in this situation, you're only generating power in the transition, the transient phase of the sprint, which already makes no actual mechanical sense. So that's number one, but also in the way that power is being, a quantum power is a scalar quantity, as opposed to a vector. So a vector has both magnitude and direction. So it has an amount, the magnitude, and it considers the direction that you're actually pushing, or the direction you're traveling. So already, we have a scalar quantity in power that only has magnitude, it doesn't consider direction. So you're ignoring, the, you're ignoring arguably the most important mechanical demand in locomotion, which is to support the body against gravity. So, while most of the, well, most if not nearly all of the motion is happening horizontally, most of the force is being produced vertically, in the vertical direction, right? But you're ignoring that as a mechanical demand in sprinting by just going with power. So with horizontal power, but you can't say horizontal power. So you're now taking, you're taking a step further away from the most important, relevant metric, which is just sprint time. Just run faster times. And then focus on the strategies that help get you there by applying force within the time constraints that you have to apply for. So if we talk about linking mechanism to outcome, we want faster times. We don't want to maximize power when we're sprinting. We want faster times. And the way we do that is we focus on how are we applying force to the ground within the time constraints. So a lot of force in a small time frame will get you there. And then what training elements can you introduce, whether you want to look at hit looks or stuff as something to help you get there. There's all kinds of ways to skin the cat. But when we want to talk about what the outcomes are, power is not your outcome. It's a mathematical calculation that takes you further away from what's relevant. This has been very insightful. This has been this has been one of those like really deep fake. This has been good. This has been good. What is there anything else that you want to that you want to kind of talk about that I hadn't had an asked you about. Oh man, you're putting me on the spot now. I am. I got a couple rapid fire ones to wrap us up. But if there's something that you're like, you know what I really wanted to talk about this. I would say I would say the the spring acceleration stuff that I'm working on is really exciting. So just I knew you will just keep an eye out for that stuff. Because that that stuff's coming hopefully in the next you know some of it will might it's hopefully coming like in the next year or so. Coach, Coach Moyan is helping me out with some some footballers for that that that 40 yard dash paper that I was just telling you about. But I yeah, I got some I got some exciting stuff brewing as far as spring acceleration. It's one of those things I can't really talk a whole lot about because you know with science you have to get keep until you actually have things to share. Yeah, and anybody that thinks he's being a jerk about that like no like in this like you're not supposed to talk about the results until things are published. And if you do it's kind of like this guy's being a jerk so like he's yeah. Yeah, I was on a podcast like a month ago and I was kind of I was kind of you know saying that same thing that you know I got I got stuff in the works can't talk too much about it just you know because it's it's in the process of you know being written and submitted for peer review and then but once it gets published and except and all that then it's like hey everyone like these really cool findings but until then I kind of have to play hold my cards to my chest and that that was not received very well by the on this particular podcast in terms of the audience. Well this guy's a gatekeeper. He was pointless happens. Oh yeah, it's brutal but you can't pay attention to that stuff. All right, so we already talked about another performance metric you think is misunderstood. What is one variable coaches don't pay enough attention to? Oh goodness. I think their their athletes ability to manage ground reaction force with respect to their center of mass. I think because because he athletes it's it's really all about how you can how can you manipulate your your momentum really that's how can you manipulate changes in momentum and the way you do that is paying attention to the timing constraints you have to apply force. So force within your the timing window that you have available is how you manipulate your body's momentum. So I think that relationship I think is is where you're going to get the most the most juice for your squeeze is is is is understanding the impulse momentum relationship and it's it sounds like it can be very complex but really at the end of the day it's very simple and so it can help you avoid some of the pitfalls with some of these other systems like your FVP profiling because if you have a firm grasp on this impulse momentum relationship it's it's the it's the most mechanical it's the most important mechanical relationship to describe an athlete's motion. You can you can avoid a lot of a lot of junk and that's that's floating out there. Does that tie and do what's the most common misunderstanding thing about elasticity? The most cow goodness I think no it can because when we talk about whole body motion versus the what the muscles and tendons are doing to get that whole body outcome then those are two different things and I have a perspective of a comparative biology background as well where I have looked at how individual muscles actually behave we measure it in animals so because we can do things with animals that we can't do with humans so I think as far as at elasticity we talk about oh this person's more muscle driven this person's more elastic driven but what you really have to understand is that the tendons only store and return energy the muscle is where it develops right so the muscle that has developed the tension so the so the tendons can store and return it right that is a universal concept so when we talk about athletes being more muscle driven versus more elastic driven it's sort of a false dichotomy. What what's one question every coach had asked before trustee day metric? Is this metric giving me what I think it's giving me? not just taking for granted that just because a metric is it's shiny it's on a force plate software or it's or what have you or we've been using it for years or my mentor has been using it since you know 1985 and that's how I use it today is the metric giving you what you think it's giving you and understanding the the mechanics well will help you to make that determination. What's one belief in performance science that will not age well? I think something that's already dead. I think I think something that's already starting to rear its ugly head is the fact that just more data is is better or more data is is good because like I said the access to tech the access to data is severely outpacing the scientific literacy needed to actually find meaning in these things and actually use them to help your athletes. So I think something that's already not beginning to not age well is this this huge uptick in using advanced technology but not with but not having a lot of care with with am I able to interpret this am I a do I have the specialized skills and training to to actually get some benefit out of this. That's where strength coach network and Brooks performance methods come together and yes sir as you keep people yes sir let's go. Final question then to wrap it up what is one thing that people do not know about you that you want people to know? That's a good one I think well I'm a full time that could denic right now I mean I have to have that's that's what that's my that's my day job but I have a strong strength conditioning strength and conditioning background and I maintain a practical presence in that I do consulting for individual athletes but also coaches who work with larger groups of athletes so I do I travel all over the place and do outdoor sprint testing and I hand off information so the issue with you know interpreting data and what measurements are important I sort of take that guesswork out of the practitioner's hands and help them actually determine what are the things that are going to move the needles for their athletes so that'd be one thing that I would probably in part with whoever's listening is that that's that's part of my job I can I can I can take the guesswork out of your athlete assessment in a very practical way brother I appreciate you spent in the last hour and half with me we were talking off here this was a blast I could have talked with you all day yeah the same here let's uh now second appearance we got to wrap up for for a third round of it yeah I'm gonna go for the to the sprint stuff is is actually done and you can talk about it we'll talk about yeah because I'm gonna have more things to talk about in the horizon so we'll get that going oh man it thank you so much Lance I have a great rest of your deck yeah yeah and let me know when you're when you're in bridgewater again oh hell yeah yeah