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Ken Clark: What Makes An Athlete Fast?
735 Plays14 days ago
In this episode, Les and Danny sit down with Ken Clark. Ken is a leading expert in speed and sprint biomechanics, serving as a professor in the Department of Kinesiology at West Chester University in Pennsylvania. He holds a Ph.D. in Applied Physiology and Biomechanics from Southern Methodist University and is recognized for his scientific research on the mechanical factors that influence athletic performance and injury mechanisms, with a special focus on speed development and sprint technique.
Episode Timestamps
- 00:00 – Intro | Hero, hardship, highlight — Dr. Clark’s background
- 01:30 – Sprint Mechanics | Vertical vs. horizontal forces
- 04:00 – Acceleration & Top Speed | How forces change over distance
- 09:00 – Research Insights | What separates elite sprinters
- 13:25 – Two-Mass Model | How sprinters strike the ground
- 18:00 – Foot vs. Ground Speed | Surprising biomechanics
- 23:07 – Braking Forces | Why faster sprinters brake harder
- 29:30 – Tendon & Stiffness | Pre-activation and connective tissue
- 44:30 – Injury vs. Performance | Foot mechanics and stiffness balance
- 52:30 – Training Takeaways | Plyos, strength, and sprint programming
- 01:01:55 – Closing Thoughts
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Transcript
Introduction and Personal Journey
00:00:03
Speaker
I hate podcast intro, so I'm just going to ask you give me a quick hero, hardship, highlight, ah you know, a minute intro. Yeah, absolutely.
00:00:14
Speaker
ah Gosh, my hero, definitely my parents. And, you know, I just had a great upbringing. And I think, you know, my ah my my mom's been my rock. and And my dad has really been the ah guy that i've I've looked up to as far as like being in the athletics and then sports science and that sort of thing.
00:00:33
Speaker
um My dad started the company Speed Science when I was just out of college. And he and I worked together on it when I was 22 years old And so that's like I've only lived and breathed one thing since I was a little kid.
00:00:46
Speaker
ah Hardship. I was born slow. That's not a real life hardship. but My dad was pulling me with a bungee cord when I was seven years old. I was doing overspeed when I was seven with a bungee cord and doing everything and anything I could to try to get a little bit faster.
00:01:01
Speaker
That's not a real life hardship. We'll keep it in context. But as somebody said that to me a long time ago, no one dies of a slow 40 yard dash. But anyways, ah yeah, that's ah that's definitely something that's motivated me my whole life. And what was it? What was the third thing? I already did.
00:01:16
Speaker
The highlight of your career. Yeah, gosh, highlight of my career. um it's been ah It's been a really good year. i got a full professor this year. I've gotten the chance to work with some you know really elite athletes on the track with USA Track and Fields, some of our gold medal winners, which has definitely been a ah career highlight. So a lot to be thankful for over the over the last calendar year.
00:01:38
Speaker
No, I love that. And we'll we'll get into some of your origin story and and what you're doing with ah Westchester Lab and origins with ah SMU and all that.
Key Factors in Speed
00:01:47
Speaker
But the first question that I want to ask is about what makes someone fast? Is it bigger forces? Is it higher frequencies? Like what makes someone faster?
00:01:57
Speaker
great Great question and great starting place. So yeah, I think you know from ah a kinetic standpoint, from a forces standpoint, it's it's ah that's where you have to start. um you know i always actually start with top speed and then work my way backwards that's just part of ah to acceleration. That's just kind of part of my training, I guess, and and where some of my research has been been been focused. But if you...
00:02:18
Speaker
If you look at some of the, you know, kind of paradigm shifting um research studies from my ah my mentor, Dr. Peter Wayans, when he was at Harvard, and then some of the the research that we put out when ah when I was a doctoral student at at Southern Methodist.
00:02:31
Speaker
Yeah, I mean, applying more vertical force in shorter ground contact times is, I is i think, you know, the the big rock of of top speed sprinting. and And I do like to emphasize that it's not just more vertical force, period.
00:02:45
Speaker
It has to be more vertical force applied in a shorter amount of ground contact time. I think it's it's really um beneficial to view the limit to top speed as like, can you apply enough vertical force and enough vertical impulse in a really short contact time? So impulses is force applied for a period of time.
00:03:07
Speaker
You got to be able to apply enough impulse in a really short contact time at top speed to be really fast. we yeah We know that the that the elite sprinters are you know on the ground for 0.08 to 0.10 seconds.
00:03:20
Speaker
Team sport athletes, maybe 0.10 to 0.12. You've got to be able to apply enough vertical force fast in those ground contact times to to run fast at top speed. So from a forces, a kinetic standpoint, it all comes down to that at at top speed.
00:03:36
Speaker
We'll talk about some other related elements I know later in this podcast as it relates to the horizontal braking and propulsive forces, ah which are also important for top speed. But I know we're going to come back to that as well.
00:03:47
Speaker
So as we start with the vertical forces at top speed, clearly as you work your way back on the track to transitional
Ground Contact and Speed
00:03:54
Speaker
acceleration and an initial acceleration, the horizontal forces play a much greater role um from an important standpoint. So,
00:04:02
Speaker
You always need to to pay the piper, so to speak. You always need to apply enough vertical force and impulse to support your body weight and to and to lift your center of mass into the air ah for the next step.
00:04:15
Speaker
But with that being said, once you meet those requirements, the athlete that can apply the most horizontal force relative to their body mass is the athlete that accelerates the best.
00:04:25
Speaker
Simple physics, simple Newtonian mechanics. Force equals mass times acceleration. So force divided by mass equals acceleration. F over M equals A. So you got to be able to apply a lot of horizontal, ah net horizontal propulsive force relative your body may so mass to accelerate well.
00:04:42
Speaker
And that's, you know, that's not me saying that. That's just, again, that's ah Isaac Newton there. So I think that's ah that's a really good starting place. In initial
Transitional Acceleration Research
00:04:50
Speaker
acceleration, the um horizontal forces are, you know,
00:04:55
Speaker
largely net propulsive forces or net propulsive impulses, right? You have some braking impulse, but then you have more and more, ah you have more propulsive force, more propulsive impulse. As the runner continues down the track or down the turf, as they get from, you know,
00:05:11
Speaker
the steps one and two into steps, you know, seven or eight at around the 10 meter mark into steps 15 or 20, the body becomes more upright to state the obvious. And the the force vector, the resultant force vector goes from more kind of angled forward to more upright.
00:05:27
Speaker
And so, you know, those forces go from being a little bit more horizontal to a little bit more vertical as the athlete approaches top speed. um If you look at transitional acceleration, this is obviously a very long-winded answer I'm giving you about force. No, this is great. This is very...
00:05:43
Speaker
I have more and more thought that that transitional acceleration is really key. So it's, it's, you know, relatively easier to to look at like top speed in isolation, like maybe 40 to 50 meter segment. And then you can look at the start like zero to 10 meters.
00:05:57
Speaker
And that's very important and necessary to look at those kind of in, in isolation or maybe to, you know, analyze data zero to 10 and 40 to 50, whatever. But I think, um,
00:06:08
Speaker
One piece that I'm very interested in and where there's relatively less research is that transitional acceleration piece from what's going on from 10 meters to 40 meters or 10 meters to 30 meters. And Ryu Nagahara and his lab have obviously started to tackle that over the last decade. Steph Collier has been part of some really good research studies there.
00:06:29
Speaker
So there is emerging research, but I think that's going to be a really key point, both kinetically as it relates to the forces and kinematically as it relates to the ah technique, the limb mechanics, as we move forward over the next decade.
Research Journey at SMU
00:06:43
Speaker
Kind of figuring out like, okay, we we basically know what makes somebody good from zero to 10, but what is what do people do that are really good from 10 to 40, and how does that allow them to bring in more momentum, more velocity into the top speed phase?
00:06:58
Speaker
And I think that's going to be really, really key. On the physics and mechanics standpoint, Well, they they continue to apply more net propulsive impulses during that transitional phase.
00:07:09
Speaker
So I think, you know, we we kind of know that answer from Ryu Nagahara and Steph Collier's work, that sort of thing. I think marrying up some of the other elements, like what are they doing from a, you know, technique standpoint, a kinematic standpoint, um and what are they doing from like a muscle activation standpoint, that needs to come along. So...
00:07:26
Speaker
Let me summarize my answer about kinetics. ah And then if I could add in a piece about kind of kinematics, I will. But of course, if you guys have any questions as I'm going along, ah please feel free. No, keep going. This is great. Yeah.
00:07:39
Speaker
Yeah, so I guess just to summarize, you know, if we start if we start at the start, hey, enough enough vertical force and impulse to support your body weight and and lift your center of mass into the next step.
00:07:50
Speaker
Just enough time to kind of reposition your limbs for the next step. um From a horizontal impulse standpoint, you know, you need to essentially maximize um your horizontal propulsive ah forces and and impulses. It may be a little bit of an oversimplification, but ah generally speaking, more horizontal force force and impulses better during initial acceleration.
00:08:11
Speaker
During transitional acceleration from 10 to 40, if you want to phrase it like that, as the body becomes more more upright, you need to apply more and more vertical force to to meet those demands while still applying a net horizontal propulsive impulse.
00:08:28
Speaker
And the athletes that can manage both of those things, we'll talk about managing braking forces later, I know, But the athletes that can continue to to the um apply a net horizontal propulsive impulse are going to continue to build velocity and momentum into the top speed phase.
00:08:43
Speaker
And then at top speed, again, comes down to from a vertical standpoint, vertical force standpoint, ah applying a lot of vertical force in very short contact times while still being able to manage those those breaking impulses.
00:08:56
Speaker
So that's the that's the kinetics. That's the that's the forces of it. And I'll pause here in a second. There's obviously kinematics that go along with all three of those phases that we can get into as as well.
00:09:08
Speaker
um And of course, kind of like muscle activation as well. So that's what I think. But I'll i'll take I'll take a break. No, that was, that was incredible. thats I was catching myself taking notes like I'm in a class.
00:09:21
Speaker
ah That was really good. um Now just to I want to take a step back and then we'll come back to some of the kinetics and kinematics side of things. But um what problem in sprinting did your work at SMU like set out to do? Yeah.
00:09:34
Speaker
And then what did you not expect to find? Like, did it change in that, in that process at SMU when you're doing the research? Yeah. Yeah, great, great question. And thanks for bringing that up. It's ah it's a fun story to tell.
00:09:45
Speaker
I completed my master's degree at Westchester in 2009. I moved down from Philadelphia to Dallas in 2010. I joined the SMU Locomotor Performance Lab.
00:09:56
Speaker
directed by Dr. Peter Wayand. Our research engineer was Dr. Larry Ryan. I was there for for five years. um And it was you know one of the best times of my life, both personally and professionally.
00:10:06
Speaker
ah Peter and Larry made the the research experience incredible for me. We set out basically to answer the question of what makes fast people fast, much like we're talking about here.
00:10:17
Speaker
So Peter's two other publications in 2000 and 2010
Limb Mechanics and Braking Forces
00:10:21
Speaker
had highlighted the importance of vertical force. So that was that much was already known. But we didn't really know much at 2010 or 2011 of like how that was being accomplished.
00:10:31
Speaker
Like what were faster runners doing from what we term a force signature standpoint or how the force was getting applied? What limb movements were accompanying that or corresponding with the more force?
00:10:44
Speaker
All we really knew based on the existing research from Peter and others was like, OK, faster runners apply more vertical force in shorter times. But the the how was was largely actually unknown. It kind of seems ridiculous to think about that now. And like 2025, like, oh how do we not know that? But that's the way it was. We didn't know.
00:11:01
Speaker
So we started off and I'll just take a ah quick side tangent. We started off thinking it was like almost purely like strength related. Like, how strong is somebody? We started off as a funny story that nobody knows.
00:11:12
Speaker
We set a bar vertically across the treadmill. People laid on their backs on the force plate ah in the treadmill, and they pushed up isometrically to see how strong their one leg was. We essentially started with isometric strength tests to see if that was the difference. and we know it's important isometric standing, but we quickly found out that there are some people that weren't super isometrically strong that could still apply force. So we kind of started there though, just with that, just with that general question.
00:11:39
Speaker
And they kind of went from there. And then we gradually kind of figured out like, no, this is a lot related to the mechanics of the limb motion, how they're kind of striking the ground and how stiff they are or are not during the initial portion of ground contact. So within like two years, 2012, 2013, had kind of,
00:11:55
Speaker
it kind of Found that out. and And I should mention with my experience there with Peter and Larry in that lab, we tested over 500 runners, Olympic gold medalists, Division I team sport athletes, Navy SEALs, Army Rangers, all the way down to average Joes, of which myself was, I'm one of those, right? So we tested everybody along the spectrum, which was really great, not only to tease it out on this very you know heterogeneous level, but also within the weeds of like, okay, well, what does a guy who runs a 10.2
00:12:27
Speaker
seven in the 100 meters do that's different than a guy that runs a 9.9, which is something slightly different. So we had the ability, given our lab setup and our sample, to kind of tease those things out. but But yeah, that's that's what we set out to do.
00:12:41
Speaker
What makes fast people fast? We kind of started really off base, but it really evolved into something beautiful. And by the end of it, we kind of had... our answer, you know, which was a a series of publications like, well, they don't just kind of follow this typical spring mass model for our, for our listeners who know what that is. It's like applying force and kind of like this upside down you type of shape that had been previously considered like the, the way you apply force for kind of like to maximally use your leg, like a spring or bounce on and off the ground. We kind of found that actually elite sprinters weren't doing that.
00:13:13
Speaker
And that also kind of was with involved in the, in the two mass model, which I know we're going to talk about a little bit, but, Those things all kind of tied together um in ah in a way that was, you know, just super fun for me to be a part of, basically.
00:13:26
Speaker
Yeah, maybe the next obvious point would be like, can you explain the two-mass model in plain, simple English? Like, what is it? how And how does it affect runners? Yeah, well, I need to hire our collective good friend Stu McMillan to come in here and explain it for me. Because I know he's ah he's got such a good grip on it that I've joked with him that he can explain it better than I can. But yeah, so in its very basic sense...
00:13:49
Speaker
It essentially says, okay, hey, when they when you look at a ah vertical ground reaction force trace um for a runner that's running on a force treadmill over force plates, what you're really looking at is is the sum of two collisions, basically. It's the sum of two impact forces.
00:14:09
Speaker
It's not just kind of the whole body rebounding on and off the ground where like the whole runner's body mass kind of comes in at the same downward velocity and then rebounds upward at the same velocity.
00:14:23
Speaker
But basically the leg, the swing leg that's about to hit the ground has its own kind of separate mass and its own especially separate velocity before it hits the the ground.
00:14:35
Speaker
So your center of mass is moving downward. If you want to think about, ah we we divide it. Let me take a step back. We divided the body into into two separate mass components. You have 100% your body mass.
00:14:46
Speaker
We divvied those up into mass one, which is basically the lower leg, the the foot, the ankle, the the shin, the lower leg was about 8%. And the remainder of the body's mass was about 92%, essentially, basically everything up above the up above the knee.
00:15:01
Speaker
Well, mass one, the foot, the shin, the lower leg, that's moving down towards the ground at a much higher velocity then the than the rest of the body is um at the instant before ground contact.
00:15:13
Speaker
And that's because the runner is winding up with their leg swing and then striking down or towards the ground. So it's got this this separate velocity. That leads to a bigger collision, especially at fast speeds, where it becomes especially prominent at like a runner sprinting, eight, 10 meters a second,
00:15:29
Speaker
That leads to a bigger collision that is observable in the force trace. So you see like this big, fast rising edge in the overall force trace. And then you kind of see like this upside down U shape for the rest of the force trace.
00:15:42
Speaker
And that's because the lower limb is essentially winding up and striking the ground. And so one of the things that came out of our research that Peter Wayand had observed early on was He's like, in 2010, he's like, well, these really fast sprinters don't have a force trace that looks like everybody else, but we don't know why.
00:16:01
Speaker
that was such a cool like research question to enter the lab with. And so by the end of that five-year period, we had a really good... theory slash model for that, which is to say, well, it's because really fast runners, sprinters get their swing leg kind of up a little higher they accelerate it downward a little faster.
00:16:21
Speaker
So it's coming into the ground faster. and And so it has a little bit of an extra collision, if you will. And so, and some of this might be aided by visuals ah for, for listeners to go kind of track this down on, you know, on about the two mass model, but essentially you end up with the sum of Two waveforms, two force traces. You have the the mass one waveform and that kind of overlays or summates with wave two.
00:16:47
Speaker
And it produces this really fast rising edge to the force trace. um To bring this back to practical applications a little bit, because I know that's ah a really in the weeds description.
00:16:59
Speaker
For faster runners at faster speeds, they can wind up their swing leg a little bit more. It comes into ground contact with a higher velocity. And then one piece we haven't talked about yet that I know we will is they're a little bit stiffer upon initial ground contact.
00:17:15
Speaker
And so there's this really rapid deceleration of that movement. shin, et cetera, upon ground contact. and And so all of that kind of leads to a higher rate of vertical force application for faster runners compared to slower runners. And the two-mass model, although it applies to all running speeds, it's most observable at fastest running speeds. And we really felt like it helped explain what we were seeing in the differences between like our elite sprinters and our and our other runners. So
00:17:46
Speaker
Again, I know that's ah that's a lot of of detail there, talking for a little bit, but that's it's kind of as probably as good off-the-cuff explanation as I can offer. No, that's great. that's great. And then do you, are you implying with this that the two-mass model leads to the spike in vertical force earlier in contact? Yeah.
00:18:04
Speaker
And, yeah, it's a great way of summarizing it. um Yeah, I couldn't put it better myself. Yeah, the two-mass model explains that spike in the in a ground force, ah vertical round reaction force waveform that that is observed with really fast runners, 100%.
00:18:19
Speaker
so I love it. Yeah. Danny, I'm sorry. I'm moving through these questions to get the background. Cause I'm, I'm leading up to something. I'm leading up to something here. Like there, this has a kind of a process to go through just beginning to end.
00:18:33
Speaker
Um, and I think we had a couple more things in here before
Muscle Tendon Dynamics in Sprinting
00:18:36
Speaker
really drop it, but the the next piece obviously is the foot speed, ground speed, um, the difference between backwards foot speed at touchdown.
00:18:45
Speaker
Um, And the ground speed difference. Do you want to walk through that? Is that, that's newer, correct? That is newer. Yeah. So, um, Yeah, and I can kind of talk through um our research at at Westchester, you know, through the present time. So um I left the SMU lab in 2015. I took over my my current position at Westchester, shockingly, a decade ago. Time flies.
00:19:08
Speaker
And then some of our more recent research from the Westchester lab, but it it was in the works since 2018, but it got published in 2020 moving onwards, a series of publications. So we started to look at the thigh angular mechanics that kind of essentially set up the two mass model. That's really where it kind of came from, was saying like, OK, the limb velocity at the instant of touchdown, that's what we have observed.
00:19:32
Speaker
and the kind And the collision and and the fast deceleration, that's all part of the two mass model. The source of that, though, is up the chain, is up at the hip. as the athlete kind of gets into the block position and accelerates the thigh and the leg back down to the tracks. We kind of got into that with our whip from the hip paper from Westchester and our thigh angular acceleration. And then the third paper that came out of that looked at foot speed.
00:19:56
Speaker
So it's kind of a triad of papers that were kind of focused on on that element of it. And so it's it's relatively um relatively new stuff. That foot speed paper was published in 2023.
00:20:07
Speaker
And it's um it's interesting and a little bit counterintuitive. So essentially, we've already identified that faster runners have faster downward foot speed into the ground prior to prior to ground contact. and And that is certainly related to the two mass model. That's a but big part of it.
00:20:23
Speaker
What we looked at more recently was what is the foot doing ah horizontally relative to the the body, like the quote unquote negative foot speed? Like is the is a foot moving backwards towards the body, towards the center of mass more technically?
00:20:40
Speaker
And then what is it doing relative towards the environment, like relative to the track? And those are two different things that become a tiny bit um not as straightforward. So... Towards the body, the foot moves backwards pretty rapidly right before touchdown. For an elite sprinter, that may be like seven or eight meters per second backwards in the coordinate system relative to their center of mass. So if you just looked at the runner, you know, yeah and and you just looked at them kind of like, where's the foot moving relative to their hip?
00:21:11
Speaker
Relative to their hip, it's moving backwards. But if you look at it relative to the track, it's actually still moving forwards and that's termed ground speed difference.
00:21:22
Speaker
So the foot's moving like maybe seven or eight meters per second backwards relative to the the runner, but it's actually still moving three meters per second forwards relative to the track.
00:21:34
Speaker
And so this is where we're going to get to breaking forces. I know one really kind of counterintuitive thing we found was that faster runners have and you might the readers might need to or the listeners might need to read the article to fully grasp this or ask me questions online afterwards. But the foot is moving faster backwards towards the runner.
00:21:57
Speaker
in faster runners, but it there's also a bigger ground speed difference. So if you take the fastest, you know, runners out there, they do have a ah bigger quote unquote negative foot speed, but actually they also have a bigger ground speed difference.
00:22:10
Speaker
There's actually a bigger Delta between their foot, uh, and the, and the ground moving forwards. And and so this does, I think tie into, uh, breaking forces, which we can get into momentarily. So, um,
00:22:21
Speaker
The classic, like, hey, you want your foot to be moving backwards fast towards your hips or towards your center mass. Definitely true. Definitely true. But it's also ah counterintuitive that the that the foot is is not going to be like basically, um it it's it's not going to be moving like just straight down. There's going to be some forward ground speed to it and that's actually going to be larger and faster athletes.
00:22:46
Speaker
So I'll pause there before I get too much in the weeds. No, it's interesting. And going to have Danny hop in after I say this big thing here. um Because um I want to talk about, I think the thing that I've been obsessed with the most the past two weeks has been breaking forces and sprinting.
00:23:04
Speaker
And Stu's talked about it the Huberman podcast. yeah He's talked about it on the Rich Roll podcast. um there's a couple coaches that are just talking about how they're they're training their athletes physically for the demands of sprinting.
00:23:17
Speaker
You said something to me in text, and i don't know if I'm allowed to say it, but I'm going say it. Faster runners have larger braking forces. Why is that? its just wise ah ah yeah Danny, do you want to chime in? or I'm um'm happy to.
00:23:29
Speaker
keep running. I'm still trying to figure out what what I'm supposed to provide to this. Like, this is all basic information. I'm sitting back here just learning right now. Y'all keep keep rolling with this. I got two pages of notes. Yeah.
00:23:42
Speaker
Well, there is some unpublished data, I'll put it that way, to have access to where we had, you know, faster and slower runners and the the faster runners had larger braking forces than the slower runners, which was an unexpected finding to be sure, at least at that time, was unexpected findings.
00:23:58
Speaker
There has been I think some conflicting um ah data that's in print, ah ah one study at least I know of that has shown that faster runners do agree with that, like had faster braking forces. There's one, I think from Steph Collier and Ryu's lab that showed maybe something that was a little bit more equivocal, um like that the way they manage braking forces or had lower braking forces during certain part of the ground contact phase.
00:24:24
Speaker
But here's the here's the big picture thing that I think is true from a physics standpoint. there we The result, unless I don't know if this is the detail you want me to go into, but I'll provide it anyways. We're diving in now.
00:24:38
Speaker
This is in the weeds. This is really in the weeds. Okay. There's a resultant vector in the sagittal plane that has both vertical and horizontal components to it. That resultant vector has to basically align close, somewhat closely aligned with the center of mass for reasons of dynamic stability.
00:24:58
Speaker
So for athletes that have larger vertical forces during the first part of ground contact, and we know they do, that's an established fact, Larger braking forces is not an unreasonable occurrence, given that that vector has to basically align with their center of mass.
00:25:18
Speaker
If there is larger verticals without corresponding larger horizontals, that could conceivably... yeah not align with the center of mass, that resultant vector would conceivably not or resign align with with the center of mass, which could be a ah dynamic stability challenge.
00:25:32
Speaker
So there's that part of it from a pure kinetics standpoint and and kind of balance standpoint. And then there's this other piece, which I'm not sure how well I explained this, but the faster the athlete, actually the larger the ground speed difference they might have. Actually, the larger the difference between how fast they're moving forward forward versus how fast their foot is coming backwards, how fast, that what that ground speed difference might be, that may kinematically contribute to larger breaking forces as well.
00:26:03
Speaker
In other words, there's both kind of these kinetic reasons and also these kinematic reasons that may contribute to faster athletes potentially having larger breaking forces than their slower counterparts.
00:26:18
Speaker
Um, I should add a real big caveat here. I'm not saying that you should train or coach an athlete to actively pursue larger breaking forces.
00:26:29
Speaker
That would not be advisable um from just a purely technique standpoint. We'll get into the assisted sprinting piece and all that stuff. And you might also see... Hold on one second. Yep. I think... just want to make sure I record him.
00:26:47
Speaker
Okay, we're so good. Sorry about that. We'll edit that. I said our recording stopped for a second.
00:26:56
Speaker
Okay, I think we're good. All right. Sorry, keep going. No, that's okay. I'll just start kind of from the top of that last phrase. So you you might actually find like a developmental athlete who like really overstrides and heel strikes and lands way out in front of them. They are also going to have really, you know, large breaking forces, not in a good way, not in a good way.
00:27:16
Speaker
As Les had messaged me at one point during our text conversation, high vertical forces with corresponding high braking forces, probably not a bad thing and probably unavoidable.
00:27:27
Speaker
Low vertical forces and high braking forces, that's problematic. So so there there are some nuances to this for for sure. But I think you know constantly saying, hey, you don't want any braking force is is not probably accurate from a mechanical or possible.
00:27:45
Speaker
from a mechanical standpoint. Yeah, that makes sense. And then just thinking about it, like in terms of like practicality, like the, the greater, the faster you go, the, the the foot tends like to get a little bit further touchdown distance, like away from acceleration, acceleration you might have under the, under the center of mass. And as you gain speed, that touchdown distance gets little bit greater. yeah,
00:28:11
Speaker
Like the break is inevitable. It's kind of like saying like um if I were to do a depth jump, but I'm trying to reduce the breaking. It's like you can't. ah You're not going to reduce the breaking. and The speed of of the drop is going to determine the break you need to apply.
00:28:26
Speaker
um and Which makes me think about also is like if I think about the ground contact and I split it in half. In that first half for ground contact, but I'm trying to move through that phase as fast as possible, efficiently as possible to get to the second half and earn the rights the second half.
00:28:41
Speaker
um So like it's unavoidable. And the harder you hit down, the bigger the breaking force that that will occur. Is that correct? Yeah, great points, and it's a great way to put it, right? So we're talking about bigger braking forces, but again, impulses is force times time.
00:29:00
Speaker
Bigger braking impulses are not necessarily beneficial. You want to get through that braking phase as fast as you can, as you said, to get to the propulsive phase, 100%. You got, as ah as I know we'll talk about, you got to manage
Training Strategies for Sprinting Performance
00:29:13
Speaker
those braking forces during the first half of contact to get to propulsive phase.
00:29:18
Speaker
And, you know, I i think it's a it's one other point that's worth going into. During top speed, it is not possible to land directly under your center of mass. It's it's unavoidable, as Les just said. During acceleration, there's ah there's a kind of this common misconception that, hey, you can land right out underneath your hips at top speed. it It's not true. It may not be like a bad coaching cue to say, hey, land underneath yourself. Like, that's not...
00:29:43
Speaker
bad, but just for like clear cut mechanical terminology, you, the runner is going to land out in front of the, in front of themselves a little bit, 20 to 30 centimeters, something like that. So there's going to be a breaking force.
00:29:54
Speaker
How fast can you get through that and get to the compulsive side of things? Probably, you know, good to consider. Yeah. One thing that i I think about this is that, and I have a question on this, like I wrote this down in my, in my notebook is this breaking load the next phase.
00:30:11
Speaker
Because essentially the stretch shortening cycle, you jump, you have the eccentric portion of the jump. that That breaking in that eccentric phase creates... um and and I think you're loading the spring, right? yeah And I'm not sure I always viewed it that way, but I think that's you know think that's become a little bit of a more...
00:30:29
Speaker
commonly discussed concept. And I think there's a lot of merit to that, which is to say, ok especially when we talk about a top speed, the athlete, you they're going to land with their foot out in front of them. There's going to be braking forces. If you're applying a lot of vertical force, those braking forces might even be a little higher.
00:30:45
Speaker
know, that's not like any of that is necessarily a negative thing. thing from a musculotendinous standpoint, you're loading the springs that you do and when you get on the other side of that thing, you know, it's, you know, there's there's going to be some energy return into the, into the propulsive phase. So yeah, I think all that kind of goes hand in hand from, ah you know, from, we talk ah a kinetics and kinematics and now we're essentially talking yeah muscle activation or musculotendinous behavior, that sort of thing.
00:31:11
Speaker
So yeah and And Danny, my next question is for you on this. and And this is probably where you can provide the most insight on this is but um with the muscle tendon unit at at breaking.
00:31:23
Speaker
Like we know that there's bone, there's a tendon, there's muscle in between, there's a tendon, there's a bone, right? So from that standpoint, the lengthening that's happening on the ground contact is Like, how do you manage that with a muscle tendon unit? Is that, is that like the tendon is stretching and the muscle stays stiff isometrically? Like how does, I did my research, but you're the guy on this.
00:31:48
Speaker
So. Give me one more context. Are we, are we kind of picking up off of like the posterior tip conversation that we were having last week? Yeah, somewhat, somewhat. But like, um I'm reading about this from the standpoint of like, you have your muscle spending your muscle spindles and you have your Golgi tendon organ, right?
00:32:05
Speaker
and the Golgi tendon is trying to protect that you know that ripping, that that injury from happening. And um what we're trying to teach our body is is to allow the tendon to elongate and stretch and create that preloading while the muscle has some stiffness in it. Because if it's the opposite way, if there's too much slack or the tendon is too loose, then basically what's going to happen is that the muscle is going to have to stretch at a rate that's too fast for that muscle to stretch.
00:32:37
Speaker
And it's going to cause it's going to cause an issue. So i I know you see this with a lot of our sprinters and athletes. like Yeah, just shoot me your comments on that. Well, a couple of things come to mind here. like the the The first thing is is the the individuality and strategies.
00:32:55
Speaker
So we've we've talked a little bit about this actually on the last episode, but you know this is where for me, like the quadrant mapping and the work from Wild and everybody was was exceptionally helpful for me you know to be able to kind of differentiate the loading strategies and and just...
00:33:10
Speaker
To put it very simply and in layman terms, like, are we more connective tissue driven or are we more contractile based? Right. And we've we've seen that get organized, you know, a little bit more ah sophisticated through the quadrant strategies.
00:33:24
Speaker
I think the the important thing is understanding that there's like a like with anything else, there's a standard bell curve. So if we're running, you know, 40 yards or if we're running 60 meters or whatever it is, irrespective of who you are, how fast you are, what age group you are, there's these, you know, general qualities and demands that are going to be at place.
00:33:44
Speaker
So we need to make sure that those base priorities are met. Once we get past that first entry point, that's where we start to look a little bit deeper at some of the mechanics, some of the these strategies and and these different ratios of flight and rate or or ground time and air time.
00:33:59
Speaker
um you know and And basically looking at it as what are the training parameters that we need to apply that are going to be more conducive for this strategy.
00:34:10
Speaker
So if we relate this to the combine phase, what we did early on was looked at it as kind of filling buckets. So for instance, the athletes that were more, um you know, quote unquote, vulnerable through connective tissue structures, we wanted to try to fill that bucket early on through training strategies, through your different cueing and drills that you were setting up.
00:34:32
Speaker
And then as we transition into more of the back end of the combine, That was where we wanted to kind of emphasize more of their strengths. So we wanted to feed what was already strong. I think there's a really important ah aspect of timing with this, where for for a long time, at least, you know, speaking for myself here, I always kind of looked at it as being more binary.
00:34:54
Speaker
Like, okay, Les is going to be very force driven. is going to be more connective tissue driven. So those are the things that they do well. You know, let's just kind of feed that.
00:35:05
Speaker
And I think what happens is, is when we transfer this into more of game speed, we don't have the the preferential basis of utilizing what we do well all the time.
00:35:16
Speaker
Right. we We have to be able to be a little bit more robust and more variable to how we can produce these strategies. So circling that back to your initial point, I think that the biggest thing is, is the training parameters that we're using.
00:35:30
Speaker
So it's not necessarily what we're doing, but how we're doing it.
Hamstring Mechanics and Injury Prevention
00:35:34
Speaker
We can do a split squat in 500 different ways and get different adaptations throughout those.
00:35:42
Speaker
From the tempo that's applied to the the load or the intensity that's applied, static versus accommodated loading, we can look at the positioning of the load, where the bar placement is.
00:35:52
Speaker
All of these different factors are going to just bias more or less connective or contractile tissue um for this individual. So with the with the sprinting mechanics and with this eccentric braking and the amortization and the transition that's occurring, the things that I look at from really the leg down, the first thing for me is, is can you actually load through your foot?
00:36:17
Speaker
So can you eccentrically splay and open through the foot? And that speaks somewhat to, you know, predominantly to the intrinsics when we're talking about the splaying of the foot, but we also can't forget about the extrinsics.
00:36:28
Speaker
right Like the extrinsic muscles of the lower leg are the ones that are producing the majority of the actions. So that initial ground contact, I think about trying to create a bigger surface area with the foot. So having the ability to eccentrically load and splay through the foot and then less tying in what we were talking about last week.
00:36:47
Speaker
The actions of the posterior tibialis are extremely important for this ground contact, breaking, and then turnover conversation that we're having. And Ken, to kind of give you a little bit of context here, what we noticed with one of our bobsled athletes was when we put him in this position of...
00:37:05
Speaker
Elevating the heel, bending through the forefoot, and then having his center of mass leaned over that access point of the midfoot, immediately dropped out of the position.
00:37:16
Speaker
If he's able to rotate his foot or he's able to manipulate his center of mass relative to that access point, he can hold it forever. And he's actually a really, really impressive kid. like Extremely explosive, very powerful, very strong, fast.
00:37:30
Speaker
But the minutia of this is that what we are doing, if we can't get center of mass over top of that access point, is we are inviting that rotational compensation strategy where we're not actually getting full locking of the navicular of the midfoot.
00:37:46
Speaker
And if we can't get that locking mechanism, then we don't get that full eccentric stretching of the plantar, plantar fascia or plantar surface. So then we have to utilize rotational mechanics in order to create propulsion because we can't get to that full point of locking it isometrically in in that plantar flex position. And I think that's a really important factor for this.
00:38:09
Speaker
no that's That's amazing. Which leads into like the stiffness side of things, Dr. Ken. like what talk Talk me through the stiffness side from, ah I guess, a kinetic standpoint. And then I'm going to Danny just about a little bit more on what might lead to lack of stiffness.
00:38:26
Speaker
Yeah, so that's such an excellent excellent explanation. then Yeah, as my mind kind of going a little bit. So I'll say this. why i think my my yeah um viewpoint on on a lot of things has evolved over the last 10 years, and i and I think stiffness is is one of those things. So I think, you know, in 2015, kind coming out of the lab, it's like, all right, well, leg asses strike the ground.
00:38:49
Speaker
Everything is just going to be like perfectly rigid through the foot and the lower leg. You know, no no yielding, et cetera, like zero. I'm obviously talking in the extremes here. And that's what's going to lead to the, you know, the really fast deceleration of the lower leg and the fast rise in the vertical force trace. And that's what it takes to to really run fast.
00:39:09
Speaker
And stiffness is clearly important. And i'm going to come back to that in a second. I'll just say that, you think my, my concepts of stiffness have definitely evolved over the last couple of of years in particular, you can look at, you know, a lot of different runners, fast runners, and they're managing that stiffness in different ways, especially doing things out of the sagittal plane. Like there's a lot of different stuff going on in the lower leg, you know, both frontal and transverse plane that are important to look at, but I'll speak.
00:39:39
Speaker
Now, in generalities, you need to be able to have the the leg come in to the ground with a fast foot speed downward, backwards towards the center mass. And it needs to be able to strike the ground and have some threshold level of stiffness so that the the foot can anchor to the ground, so that the force can trans be transmitted, and so that the body can get to the propulsive phase, as you've said, corrective.
00:40:05
Speaker
quickly So there's going to be some heel lowering towards the ground. There's probably going to be some internal rotation, etc. But there's, you know, an an optimal or threshold or nebulous terms that are hard to define.
00:40:18
Speaker
But it can't be too much that the lower leg is collapsing into the ground, mushing into the ground, to use very non-scientific terms. At that point, you know, then then clearly there's going to be a delay in how fast they get to the propulsive side.
00:40:32
Speaker
There's going to be, you know, energy leaks or a lack of force transmission, etc. So I think it's, um you know, it's it's some... ah optimal level of stiffness so that the foot, you know, contacts the ground on the ball of the foot.
00:40:48
Speaker
Clearly, so there's some movement in the frontal and transverse plane and clearly the heel is going to drop. For some elite runners, the heel kisses the ground on certain steps. For some, it doesn't. It can run. It can differ step to step.
00:41:00
Speaker
But the runner's got to be able to decelerate the lower limb, anchor the foot to the ground, and then get into the propulsive phase efficiently. So I think that to me is now what I define as my working definition of, of you know,
00:41:13
Speaker
um optimal stiffness, whereas there was a time probably back in 2016 where i said, well, you got to maximal stiffness. You just hit the ground and the whole thing's rigid and that's that.
00:41:26
Speaker
And, you know, it initially it was Stu who was one of those guys who got me to kind of reevaluate that thought. Well, like well your leg's just not like this rigid rod that, you know, you break the ground and it's just like this metal crutch that you pivot over. Like there's going to be some compliance. It's not just like maximal stiffness all the time. So, yeah. So anyways, but but but you do have to have certain requisite levels of stiffness so that all of those things can happen effectively.
00:41:50
Speaker
Yeah. And, you know, just think about the stress shortening cycle and and this, like, like the tendon, like, is the storage site for elastic energy. In order for that to to actually happen, the muscle has to contract and stiffen ah prior to contact.
00:42:06
Speaker
So have some type of pretension and then remain stiff and connected that during the first two processes, which would be like the eccentric phase and mortization phase. um I'm assuming that like failure to stiffen the muscle during the eccentric, the mortization phase,
00:42:22
Speaker
would mean that the the actual effect that we're trying to get out of the tendon doesn't doesn't occur or something happens at the muscle level. Yeah, sorry. I didn't mean to interject. I thought it's a reasonable assumption, right? So you look at some of the classic research on kind of this is ah Dr. Tom Roberts out of Harvard, and he's now at Brown.
00:42:39
Speaker
And he's done a lot of stuff on kind of muscle tendon unit. And he was one of the first, and not during high speed running, and it was actually in animal models, but demonstrated that like, hey, during during level running, i.e. like, you know,
00:42:53
Speaker
what we would consider like top speed or close to it. It's the, yeah, it's ah it's the muscle that's acting isometrically in a tendon that's taking up the majority of the of the length changes. Again, animal models, so take it for what you will. But I think that's to a large degree considered still, you know, a good working theory. I think the muscle activation bit and the muscle pre-activation bit is is key, right? Like what does it mean to have good motor, if you want to just use a general term, like a motor program for for high speed sprinting, it means that the right muscles are turning on at the right time prior to ground contact to allow for that requisite level of stiffness.
00:43:31
Speaker
And if they're not turning on at the right time, if they're turning on too late or the wrong muscles are turning on, then you're going to mush into the ground and, and you know, In non-technical terms, you'll push into the ground. And in more technical terms, you're not going to get that kind of isometric action at the muscle, and you're not going to get that store and return of elastic energy at the tendon. So I think all of that is is absolutely connected.
00:43:52
Speaker
And, you know, just to put it in more anecdotal terms, there's something you can see, you know, I deal mostly with sprinters now, although that's not really my background as an athlete myself. But if you watch like a sprinter contact the ground, I mean, you can almost – see it, that there's something about the effectiveness of their ground contact where the right muscles have been turned on, you know, at the right time before they contact the ground. And that's allowing them to to kind of apply the force in the right way.
00:44:20
Speaker
So I think all of that is is just a really key piece of the puzzle. Whereas if you go to work with like a developmental football player, like a 17-year-old linebacker, that is not the case, right? So it's ah it's a really interesting and and visually observable, in my opinion, almost dichotomy.
00:44:37
Speaker
For sure. Yeah, Danny, um I will come to you with this mostly. It's like if they don't have the preactivation piece or there's something happening at the tendon or something happening at the muscle level,
00:44:51
Speaker
Typically, the way i would work is I would just be like, Danny, I don't know what's happening, but here's the problem. Solve it. like what's What's your process of of viewing it, seeing this, adjusting it, helping? because we did this for River.
00:45:02
Speaker
It's a case of probably too stiff of a tendon, which was affecting the muscle. So, yeah, talk to me about that. So from my point of view, it's it's always going to start local and then work to more of the global strategies, right? Now, my my background, my my priority is always um or you know predominantly going to be, like you're saying, injury-focused or you know mechanically something is not right, so let's investigate it. So...
00:45:33
Speaker
I always kind of treat everyone with a blank slate at first, right? we We go back to there are these general priorities that we need to have in order to run fast, but everybody achieves those general priorities in different ways.
00:45:45
Speaker
So the the first thing that we're going to do, so we take a look at it from the the SFT framework, right? the The structural component. passively, can we move the foot in the different directions that we need to move it in? Do we have good dorsi plantar flexion? Can we supinate pronate, invert, evert?
00:46:05
Speaker
Tibial internal external rotation has been a ah bigger priority for us as of late. um We know that there is a a direct mechanical relationship between the ability for the tibia to internally rotate and the foot to pronate.
00:46:18
Speaker
So when we check that, what we've noticed with football athletes, um you know, most specifically is they they typically don't internally and ah ah internally and externally rotate the tibia extremely well, at least not, you know, in most cases.
00:46:34
Speaker
So if we can't internally, externally rotate the tibia, you know, what does that mean for the hip? Because there's a direct correspondence going up the chain as well. And what I think happens in in many cases, not to overly generalize here, but if if we lose the ability to internally rotate at the tibia, then we're going to have to rotate excessively through the hip.
00:46:59
Speaker
And if we rotate excessively through the hip, then we're not getting quite as much of that sagittal plane mechanic of flexion extension, which is going to then compromise, you know, general power production.
00:47:11
Speaker
Now, from the tissue standpoint, this gets a little bit trickier and this is a little bit more and involved here, but you know we can look at it from a functional point of view where you know blesses ah Les is the one that introduced me to really utilizing these, but I've i've really fallen in love with it.
00:47:28
Speaker
the The Natera testing thing to me is is really insightful. It's simple, it's easy, you know it gives us a clear indication or number to it. So if we want to look at it from a functional perspective,
00:47:40
Speaker
We'll start with the Natero ISOs. We'll get on the force plates. We'll do some jump patterns. And then it becomes a game of kind of association, right? So if we have structural clues, we have, let's just say simply, we have a compromised ability to dorsiflex.
00:47:56
Speaker
The big toe doesn't extend very well, and we can't tibial internally rotate very well. Then we go to the force plates and we see the numbers from the ankle push ISO and we see the numbers on a single leg counter movement jump.
00:48:09
Speaker
Okay, well now i have a bounty of information and we can kind of connect the dots on this to then make the assumptions of, okay, this might be more of an eccentric focus problem or this may be more of an isometric focus problem.
00:48:24
Speaker
The Nateras are obviously a great indicator for the isometric leaks. For the eccentric factors, we're probably going to look at more secondary qualities on the um on the jump metrics, right?
00:48:36
Speaker
Once we get into the technical component, that's where I take a step back. People like you two are the ones that are going to be doing the investigating and the analysis. But we have to make sure the point here is, is that we get some tiering of testing and that we're seeing it from multiple points of view before we just come in and say, he's too stiff or he's not stiff enough.
00:48:56
Speaker
Okay, well, let's put a little bit more depth to that. Let's put a little bit more context to that. Now, we kind of hint hinted at it a minute ago, but then we also think about the positioning of this because there's there's so many different things that are happening so fast.
00:49:09
Speaker
There's a minutia of movements that we really need to kind of investigate here. And I think center of mass relative to base of support is probably the most important thing. If we were to just kind of pick one. So it's not just can they hold the shapes or can they hold these specific joint angles?
00:49:25
Speaker
It's can they do it with the right corresponding center of mass? And then how does that transfer into the actual run strategy?
00:49:35
Speaker
No, it's huge. That's huge. um Especially on the Natera side of things, because if you if you can't if you can't produce force through the gastroc, if you can't produce force through the soleus on contact, then it's going to affect the way the tendon operates.
00:49:54
Speaker
would Would you agree with that? Yeah. And let me let me actually add one more thing to that, too. um Since we're on the topic of stiffness, I think a really important heuristic for for coaches is that that force follows stiffness.
00:50:07
Speaker
So the the stiffest junction of a segment is what is going to transmit the majority of that force. so and there This goes into a lot of different things, right? but you know we We think about um like a really common pattern for for NFL guys, at least, is is very, very stiff through the the medial portion of the plantar surface of the foot and then very, very stiff through the lateral gastrocs.
00:50:37
Speaker
And I'm not entirely sure why that is, but there's there's definitely a difference that I've seen between the stiffness in the medial foot and then the lateral gastrocs. So we have to then suggest that the majority of their ground reaction forces are being channeled through those site or regions of those segments.
00:50:55
Speaker
Now, we go back to health versus performance. For performance, we have very precise inputs, we have very specific things, and we have to train them accordingly.
00:51:06
Speaker
For health, we essentially need to invert that. Or in other words, we've gotten to a point where the medial aspect of the longitudinal arch is so stiff that it's on the cusp of of creating a problem. So we need to balance that stiffness across the foot.
00:51:23
Speaker
You know, the the pronation and the big toe flexion extension pattern, essential for sprinting. Nobody's ever going to argue that. But we hit a certain point where it's like, OK, now we're getting to a point where we can't even supinate our foot because there's so much tension through that medial side.
00:51:40
Speaker
So now what happens when the player has to cut or plant or move reactively? We have to be able to have that dexterity and medial lateral compliance of the foot. So when we're looking at tissue stiffness and qualities, there are certain attributes that we want to hit. But if we keep in mind force follows stiffness, there has to be some component of balance to that at some point.
00:52:04
Speaker
Dr. Kim, what do you think when you hear that? Yeah, it's I mean, it's just great layers of of resolution, you know, kind of added to, I think, you know, what i was saying five minutes ago, 10 minutes ago. I mean, that's it's awesome.
00:52:15
Speaker
I mean, I think that's that's all the stuff that's in the weeds that's, you know, frankly, beyond my ah level of depth into the topic, but is a part of where my thoughts on stiffness have evolved over the last 10 years. Just saying like, well, it's not just as simple as hit the ground and stay as as stiff as possible, right? There's like definitely, you know, anatomical layers to that. And then there's also the different requirements that different athletes need for different times on the field, as Danny just alluded to in the last part of that of that input there. So yeah, I don't have too much to add other than to say that
00:52:49
Speaker
That is exactly why it's, you know, a little bit of a complex issue and and more complex than just say, I will just strike the ground and stay as stiff as possible. I think for we're talking straight sprinting, there's some, again, to use a very hard to define term, some like required level of of stiffness during a ground contact. But there's certainly a lot of things that that are playing into it.
00:53:12
Speaker
Yeah, for sure. Some of the research that I i did just looking looking into this, looking at Natera, Ken, you, looking at Matt Jordan, Stu, got one really cool piece of it. So one of it one of the things I read was too compliant of a tendon, muscle fascicles do more work, which causes more fatigue. So reduced efficiency, less elastic return, higher energy cost.
00:53:38
Speaker
ah You see a lot of overuse and tightness. Too stiff of a tendon, fascicles take on excessive eccentric strain. oh So poor shock absorption and an increased risk of calf strain, which is pretty similar to what we saw with River.
00:53:52
Speaker
There he is. And Danny, talk me through the River. I know we've talked about this on 17 podcasts. You're probably fatigued a little bit, but... would you okay Would you agree that he had too stiff of a tendon and that caused some of the like this excessive eccentric strain for his calf?
00:54:12
Speaker
Yeah, so Ken and for you know the listeners too, some quick context here. um Chronic calf strains, veteran wide receiver, um had I think four...
00:54:25
Speaker
both left and right, um you know grade one, two strains in a really short period of time. And the interesting thing was ah they all occurred while jogging, not even sub-maximal sprinting, but literally like run a route and then come back and just trotting back and boom, something happened.
00:54:43
Speaker
It's crazy. the It was pretty wild, yeah. um Now, granted, this is a dude who has ah an extensive injury history to include several lower leg injuries, foot injuries, um but less to your point.
00:54:58
Speaker
Yeah, I know there's people that will push back on this and challenge this point, but this is my my intuitive belief is that, you know, kind of right in line with force follows stiffness. If we have somebody who is a tendinous based mover, more of a connected tissue based mover, very robust through the connected tissue systems, you know, and it becomes to a point where it's disproportionate to the contractile capacity of the muscular tissue.
00:55:21
Speaker
then something's going to give, right? we We get too much disparity between the connective and contractile tissue properties, and then we're going to see an injury occur as a result of that.
00:55:35
Speaker
So I think this is where we we reintroduce what we were talking about a minute ago with the training parameters. It's not what we're doing, but it's how we're doing. Now, if we could put our, you know, Captain Hindsight capes on and go back and say, OK, hey, let's get ahead of this problem.
00:55:50
Speaker
What would we have done with him at that point? Well, we probably would have done a lot more concentric based loading and concentric only based loading and more kind of reflexive based loading that.
00:56:03
Speaker
has more joint displacement to try to put more load through the muscular tissue as opposed to just reinforcing his strategy of being very good with connective tissue strategies.
00:56:17
Speaker
We do that early in the off-season to try to create better distribution or better compatibility between the structures that And then once we get it to this proverbial, you know, ah compatible point, then we go head back in and we let him lean on his strengths and do what he does best. So, again, it's I only emphasize that so much because what we're not saying, we are not saying that we need to change people's preferences or strategies, especially somebody that's eight years into the league. Like that person moves the way that they move and they have the the archetype that they have.
00:56:52
Speaker
But we absolutely do have the ability to influence this through these training parameters and through these different run strategies. It always makes sense when I put it in context like this. We all know that we have three predominant energy systems.
00:57:06
Speaker
Energy systems are never working in isolation. It's always fluctuating in different capacities based on the demands. Well, the connective and contractile tissues work in the exact same way. We can't purely isolate a muscle from a tendon.
00:57:19
Speaker
It's impossible. Right. They work in tandem. However, we can address them or influence them differently based on how we bias training parameters. And it's all the things we've already talked about. And I think that's the most important part of this is that we just want to identify where people have some deficiencies early in the training phases, try to address those and then work it back into letting them do what they do best.
00:57:43
Speaker
Yeah, that's that's a great point, which leads me into a little bit of the what to do question because there's a couple of things at play here. Like you have the person that has too much slack when they hit the ground, so they need a little bit more like pretension.
00:57:58
Speaker
You have the person that's not great at breaking an initial part of contact. And then you probably have somebody that that doesn't manage the propulsive phase well or doesn't have the the actual concentric abilities.
00:58:09
Speaker
um Now, from a training perspective, I'll kind of open this up to everybody. Like starting with how fast I can produce braking forces, where should I look to?
00:58:21
Speaker
Like you could probably say that's like the braking RFD, right? How fast I can turn that system brake, and initiate that really big spike into the ground, but also have the requisite braking forces to overcome that first half of ground contact.
00:58:37
Speaker
where should I look in terms of training? I'll kind of open this up to to anyone. Yeah. I mean, I'll, ah I'll dive in, you know, it, it seems to be, there's a ah number of ways you could kind of, uh, address that. And, you know, I think, um, one thing we haven't talked to a ton of, but think is a very simple answer is, you know I think good plyometric progressions naturally work that in. And I think that's kind of a staple and in any good training program,
00:59:04
Speaker
But the ability to handle those forces, um both ah and apply the requisite vertical forces and handle the breaking forces, I think that happens to a large degree with just a lot of the better plyometrics that are out there and and that we all ah you know probably ah expose our athletes to during the course of training.
00:59:23
Speaker
mean, an athlete that can do you know a sprint bound or a one leg repeated, you know hop for distance or you know a triple or something like that, I mean, that is a great way, a simple way, not rocket science been around for whatever, a hundred years, but a great way to start to expose our athletes to that from a, from a training standpoint.
00:59:40
Speaker
And I think, you know, in different, different answer to a different question, but something that clearly in my mind still has transfer to, you know, sprinting, even though the ground contacts and the and the mechanics are slightly different than during sprinting. So that'd be, you know, kind of like a very basic starting point.
00:59:56
Speaker
um Danny, I don't know if you want to chime in with some more kind of off the turf or off the track ah things that you might bring, you know, when you're dealing with these athletes from, you know, ah tissue evaluation standpoint or something like that?
01:00:09
Speaker
Well, I mean, I'll piggyback right off of what you were saying. Like, ah you know, I think the the first thing is is like we keep talking about, right? Like the force profile here is pretty clear. Like we have to be, we go back to the same question of how strong is strong enough, right? Well,
01:00:25
Speaker
You know, i think for the majority of athletes, especially younger athletes, you know, we we improve the general strength profiles. We improve the eccentric rate of force development. We improve the single leg strength. Like you're checking a lot of boxes just from that portion right there. And then obviously run fast. Right. Like that's, you know, it kind of been in line with you're implied among the three. Yeah. I remember saying you got to sprint.
01:00:48
Speaker
Yeah, yeah. No, it's it's funny, though, because and and and of course, I'm the clear non-Sprint expert of this conversation. But when you look at it from an outsider's perspective, like it's funny to see these trends that kind of come and go. And, you know, i know over the last 10 years, we've seen probably 10 different things come in and out of this conversation. But I do distinctly remember a point in time where,
01:01:12
Speaker
you know though All the talk about speed had everything to do with running. like It was always all of these other factors and these strength factors and whatnot. and like you know I think hopefully we finally have gotten back around to the the focus point of like if you want to be good at sprinting, you have to sprint.
01:01:28
Speaker
Yeah. Keep that in mind. All of the plyometric pieces, I think that's a huge factor for it too. I mean, it's the best pure empirical way that we are going to get connective tissue adaptations specifically, you know, very short ground contact kinds, playing with ah joint displacements and and how much actual bend we're getting in those plyometrics, using that as a progression scheme from the soft tissue and and some of the structural things, you know, again, like this is really where my job resides.
01:01:59
Speaker
I don't know how much of this is applicable for just the typical general strength and conditioning coach. But, you know, for those of you who may be interested or or or working this in, like I go back to the the gross mechanics of the foot.
01:02:13
Speaker
Right. So just simple dorsi and plantar flexion. And then from there, this combination of from heel to forefoot, the compliance and the strategies of the foot and being able to achieve true pronation and then actually get into a true plantar flexion.
01:02:31
Speaker
Now I'm getting my my stew subconscious voice in my head. If we can train one structural quality to run faster, what is it? It's it's hip extension. Well, the extension of the hip is largely predetermined by the mechanics of the foot.
01:02:48
Speaker
So we have passive pure hip extension, which is great. But if we are thinking about the the byproduct of hip extension as plantar flexion, as the hip is transitioning over the ankle, well, being able to get into true plantar flexion with some degree of inversion and being able to maintain that neutral position is going to be as essential.
01:03:08
Speaker
So instead of thinking about it as this separate set of drills and we have to do band traction on the ankle and we have to do loaded dorsiflexion, like those things are fine. But I go back to, well, how are we positioning the athletes while they're under load?
01:03:24
Speaker
Passive range is great. Active range is what matters. So it's not about what we can achieve or what we can get to independently, but what we can integratively load and hold under load and velocity.
01:03:38
Speaker
It's huge. I keep thinking back. Last thing I'll say on this is I keep thinking back to what Stu and Matt Jordan have always talked about is their experience in Canada when they had like 500 athletes and 20 national teams and they were doing all this testing and they were doing jump testing.
01:03:54
Speaker
They were doing, ah they had tendo units. They had all this concentric based testing and it the best athletes weren't differentiated by these these measures. They weren't, the the highest jumpers weren't the fastest athletes or the best performers.
01:04:07
Speaker
The strongest athlete wasn't the best performer. And it just left them like, man, what are what are we doing here? Like, what what are we actually measuring? um So I have a quote from one of their, it might have been a podcast or written article, but it's not uncommon to see athletes who are average and conventional gym strength be outperformed by athletes that express strength other ways. So weaker athletes.
01:04:29
Speaker
um So the specificity of neuromuscular control for rapid force is the key here. The second piece of that is they said many athletes excel due to their ability to regulate and capitalize on increasing lower limb stiffness during rapid eccentric deceleration.
01:04:45
Speaker
Mm-hmm. So massive. So that they they came up with something called reflexive eccentrics, I guess, bouncing off of reflexive isometrics of Rekosansky.
01:04:58
Speaker
But their their ability to now look at athletes from the other spectrum of how fast can you apply and this eccentric force, which is going to help with the stiffness side of things, led to a whole different level of exercises so i wrote a lot of these down just in my research before this um so you have everything from shock which you know plyometric and shock method which is one end of the spectrum then you have over speed eccentrics you have accelerated eccentrics you accelerated eccentric loading which would be like a band you have negatives tempo flywheel so you have this whole spectrum from like
01:05:37
Speaker
high force, lot of time, high strength, all the way down to to speed. So obviously the things that are the faster entry into the landing and the faster entering into the descent is going to be more rate of force development, whereas the slower entries are going to be more strength or power or super maximal where you're you're taking a weight that you can't even lift consensually and lowering it, right? we're going to work on the capacity side of things. And I think One thing that I thought about before this is like i was really scared that strength coaches are going to say, well, strength isn't, and you're saying strength isn't important.
01:06:13
Speaker
But that's not true because you need available strength to express it fast. And I think the piece that is really important for strength coaches and speed coaches is that both sides of the equation are important.
01:06:26
Speaker
And you have to you have to build the strength to be able to express that strength or you you won't be able to express anything. So I think where I'm looking at this is it comes back to what Hunter Eisenhower has talked a lot about.
01:06:39
Speaker
Alex Deterra has talked a lot about. is developing force from the standpoint of like the slow force side of things, like conventional lifting and strengthening all the way to the other spectrum of fast force. How how fast can you express it?
01:06:53
Speaker
And then the terror somewhere in the middle where like we just talked about the gastroc being able to stiffen during ground contact and and remaining almost at an isometric position.
01:07:04
Speaker
um we've We've talked about the sole is doing the same thing. And if you can't do that, you're going to have deformation on contact. which is going to affect stiffness. So the point is, is that if you take this whole really complex solution that we're talking about, how to run faster, there's several different points that you need to identify as a strength or weakness and then target those things. So river, for example,
01:07:30
Speaker
we needed a different output than some of our combine guys like Justin Wiley. There's a completely different ah stimulus for those guys. So I know right now like you know this is a podcast. We're not going to get into what actually to test, what actually to do um But I think about it in terms of just one piece on my side is there's three pieces that you need to work on.
01:07:54
Speaker
One is the breaking rate of force development. So how fast can you move through the breaking phase? You could you can see this on a force plate jump. How fast do you move through that eccentric phase? ah It's really important.
01:08:05
Speaker
to And you could work on that with accelerated eccentrics or overspeed eccentrics, those things. The second piece of this is increasing strength, so heavier loads. So you're working on that peak braking force and also concentric force.
01:08:18
Speaker
And then the last piece would be for the youth athletes is probably like actually adding mass to to the frame, especially for team sport athletes, like football player, um which will be a little bit more of the tempo side of things and just working that in. So, yeah, I just wanted to add that piece because I was thinking about, i was like, man, we're going to have like three or four guys that are like, man, Danny, Les, and Kent said, don't do strain training, just do plyometrics.
01:08:42
Speaker
and It terrified me. Yeah. i flat really I think that's a perfect summary, though. Yeah. Go ahead. Yeah. Go ahead. Took the words out of my mouth in a good way. Yeah. I was just going to it's a great way of, I think, summarizing it so that the yeah I think that the intentions are are clear as as far as, you know, kind of what we're discussing. Yeah. I don't think anyone's saying don't don't strength train ever. That's bad.
01:09:04
Speaker
or Quite the opposite. Yeah, 100%. thought we Go ahead. Just real quick, Les, with speed too, it's it's all it seems to be one of those conversations where we we kind of have like immediately gravitated to the very granular end of it and like talking about a lot of the outliers and you know, less especially since getting involved with with you and with a lot of these youth athletes and seeing it on a bigger scale.
01:09:28
Speaker
Like, I think it's a good reminder to say, like, what works works for improving speed for the vast majority of athletes. Like, you you've got to really kind of get to a certain point before you have to start getting into some of this nitty gritty stuff or into some of this granularity, you know, and talking about You know, the differences in in the phases and different contraction types, like for most athletes, youth athletes across all levels, it's like run, get faster, do plyometrics, get stronger, you know, do some mobility here and there and you're going to you're going to be moving in the right direction.
01:10:01
Speaker
No, it's huge. It's 100% correct. Like the general stuff works. Sprinting, a base layer of strength, a base layer of like putting in other components. Like if you want to say technique or jumping or those things, like, yeah, 100% agree.
01:10:20
Speaker
um Okay, I'm gonna switch gears to hamstrings and risk because I know that Danny can nerd out on this. Ken, you can nerd out on this. um So I'll start with Ken. So based on your kinematics work and what you've studied, what are specific patterns? It could be dying of velocities, timing, ah increase strain risk, and what interventions change those?
01:10:42
Speaker
Yeah, so obviously great, great question. You know, I'll take a ah quick step back again, kind of the history of my thought process over the last 10 years. Literally 2015, I think I ah came out of my PhD and kind of had just like the one, hey, there's only one way to run, one technical model.
01:11:01
Speaker
Everybody should look like the, you know, the sprinter would put out those videos from the SMU lab that I used for a long time. I've basically recently stopped these notes was like, all right, here's a sprinter. He's a team sport athlete. This is what the sprinter's doing. This what everybody should be doing. What the team sport's doing is bad, and you're going run slower until you get hurt.
01:11:17
Speaker
And then, you know, at one conference ah a few years after those videos came out, I was presenting, and Sophia Niffias, who's a friend and ah and a great colleague, you know, said to me, what like, Ken, does what the sprinter's doing is that actually going to be good for the team s sport athlete when they're on the field to play and I was just like oh and I had no good answer for it and that's kind of where my thought process first started on like well hey maybe there's some different things that different athletes need to be doing and I'm I'm circling back around to the hamstring issue, I promise. But that's kind of where my thought process started to to change a little bit. Like, hey, maybe there's some, maybe like the KPIs aren't like identical for every athlete, depending on their sport background.
01:11:56
Speaker
But there's definitely still some some, you know, kinematics or other things that we um that we need to be aware of for sure. So I think, you know, what but the research will suggest, Jordan Maniguchi and others, is that kind of extreme positions of anterior pelvic tilt, I think, mixed in with perhaps overstriding, some, you know, some ah some physical attributes that probably go along with that are are potentially, not always, but potentially, you putting the athlete at higher risk of of soft tissue injury,
01:12:28
Speaker
I think, you know, one thing that's also interesting is there's that old joke like we are too slow to pull a hamstring. Right. But there's some element of truth to that, because what do faster runners have?
01:12:40
Speaker
Greater thigh angular velocities, greater ground reaction forces, higher, you know, probably some, you know, some increased risk due to that. Their limbs are moving through that second portion of the swing phase where they're basically trying to have to, ah for the listeners at home, to try to slow down the limb as it reaches the peak block position, slow down the thigh as it reaches the high knee position eccentrically.
01:13:06
Speaker
As that lower leg, the shank is unfolding and faster runners are going to do that with greater thigh angular velocity. That's a problem. especially if you throw on a little bit of anterior pelvic tilt. So there is almost some truth to that.
01:13:19
Speaker
you're You're too slow to pull a hamstring, so to speak, because you're going at at faster angular velocities than when your limb hits the ground. You're doing it with greater ground reaction forces. So if you marry that up with bad mechanics...
01:13:31
Speaker
perhaps a little bit too much anterior pelvic tilt. It's not always going to be problematic. You can, you can turn on a, you know, a Olympic caliber sprint race and see runners running, you know, with quote unquote, maybe not perfect mechanics, but I think, um,
01:13:47
Speaker
I think those are some positions that maybe you want to be wary of. Certainly there's the the SMAS s from Chris Brahma and Tommaso Santos, which is great and I think identifies some things to to potentially avoid. And I know, Les, you guys employ that. I think that's awesome.
01:14:01
Speaker
There's some other stuff that we've seen on ah in our own research that we can point to. And then I'll stop talking after this and hand it over to Danny. I think where my mind has really changed over the last couple of years based on our own research is Hey, there's what do a lot of fast people do versus can you run fast and not necessarily demonstrate those quote unquote ideal mechanics, but can you still run fast and run safe?
01:14:28
Speaker
And to me, that's now the million dollar question is like, what do we want to be coaching our athletes to do? Not just from a performance standpoint, but like. Hey, can you do this fast and safe and do it repeatedly basically? And that, and those are kind of the key positions that we need to be guiding our, our athletes towards. So, so I think that's kind of the evolution of my, my thought on it. And I can get into some of more of the nitty gritty on what those positions are, but, but I think that the basics are kind of like the, you the pelvic position, the anterior pelvic till, like how much an athlete's over striding it, et cetera.
01:14:58
Speaker
So, but Danny, I'll kick it over to you. Yeah, no, man, I love of the heuristic of, you know, you don't run fast enough to pull a hamstring because that that that to me is a really important part that the met beyond hamstrings, even the vast majority of soft tissue injuries, non-contact soft tissue injuries occur due to velocity, not due to outright force.
01:15:20
Speaker
Like i'm I'm thoroughly convinced on that. It's the velocity of loading more so than it is just the actual sheer output of loading. um That being said, kind of adding on to what you were saying, the other factor here with the hamstrings is that we have a muscle group that is extending and flexing at the same time concurrently. So we're getting shortening from both ends. So hamstring acts as a knee flexor, hip extensor. So as that foot is approaching the ground, we're going through a knee flexion and then hamstring or hip extension ah pattern from there.
01:15:49
Speaker
So I think this is where, um you know, it's it's really important that we have isolated strength in the hamstrings. And I think we spend a disproportionate amount of time eccentrically loading hamstrings and not enough concentric shortening. I think that's a part of the problem here.
01:16:06
Speaker
um You know, that knee flexion action and the isolated contractility of the hamstring is a major factor. And we can have all the lengthening in the world. But Ken, like you're alluding to, it's like if we know that anterior pelvic tilting is a is a vulnerability factor for hamstring strains.
01:16:24
Speaker
then why do we want to just keep reinforcing lengthening at under load at the hamstrings, right? So with all tissues, connective or contractile tissue, we always have to go back to this balance component.
01:16:37
Speaker
If it lengthens, it needs to shorten. So if we are doing everything from a lengthened position, it's very important that we have some flexion in our programming. The other factor then becomes the rotational aspect here.
01:16:49
Speaker
So what we notice a lot of the times is a very, very common pattern is we see a lot of external rotation to facilitate hip extension. So we're we're compensating through the small glutes and we're kind of bypassing some of the load that's going through the hamstrings and we are utilizing this rotational whip strategy to produce our hip extension.
01:17:10
Speaker
Well, the opposite muscle group of the ADductors is the ADductors. And what we've heard, um you know, is another heuristic kind of with this conversation is that the adductor magnus works as kind of the fourth hamstring.
Role of Adductors and Hamstrings
01:17:23
Speaker
Well, the adductor magnus should be a synergist to support terminal hip extension, but should not be a primary driver of it. But if we have weak concentric hamstrings, we compensate through an external rotation strategy, we're putting the adductor magnus at length and then asking it to be a primary mover, well, then we are just simply asking for something bad to happen.
01:17:47
Speaker
So I think that's an important part of this conversation too, is making sure that we have appropriate balancing between AB-AD doctors and then the isolated or independent strengthening of the hamstrings as well.
01:18:00
Speaker
That's huge. talk ah like Double click on that. The adductor is the fourth hamstring part. Yeah. So the adductor magnus is an interest has an interesting geometry to it.
01:18:14
Speaker
um you know So like if we think about the other adductor muscles, right the brevis, gracilis, these are more kind of like just purely vertically oriented. right We're going kind of from the hip down to the knee.
01:18:28
Speaker
But the adductor magnus actually kind of like wraps around the backside of the thigh. And it has a very close insertional point to all three of the hamstrings. So the ah the proximity of the anatomy is very close.
01:18:41
Speaker
But the magnus again should work first as an adductor. It should support as an internal rotator and then act as a synergist through extension. Now, the interesting thing about the adductor group is the adductors work all primary planes of hip action.
01:19:00
Speaker
We adduct. There's actually some adductors that work as abductors in synergy. We have adductors that work as flexors and internal rotators. And then we have adductors that work extensors and external rotators. So it's a fascinating and muscle group.
01:19:16
Speaker
But getting back to the point here, the the premise of this is that when the hamstrings are weak, the Magnus is the first thing to become a compensator. So that's the first step is that we have to make sure we have independent hamstring strength. And that's predominantly speaking to the concentric action.
01:19:35
Speaker
Then we think about utilizing the Magnus as a support or a synergist muscle in that extension pattern. So we need to train the height the hamstrings independently, we need to train the adductors independently, and then we go to the integrative approach, which ties in the positioning and the cueing of the movement that we are having the athlete do.
01:19:58
Speaker
So if we see, for instance, this externally rotated strategy, well, the heuristic from a structural standpoint here is we need to reintroduce them to their midline.
01:20:11
Speaker
So this can be as simple as getting into a bilateral hamstring bridge and just cueing them into some hip internal rotation. I guarantee you if you work predominantly with 15, 16 year old athletes, you're going to have cramping across the board.
01:20:26
Speaker
It's just going to be an immediate cramp, right? So reintroducing the athlete to the midline from a supported, controlled, isolated manner, and then taking that concept and building it into things that are more vertically integrated.
01:20:44
Speaker
So an an easy example of this would be instead of just having athletes do a, you know, dumbbell bilateral RDL, put them on one leg, give them one dumbbell in the opposite hand and have them cross their body towards their pinky toe and get them to actually engage some of these rotators, right? And being able to do it at length while holding a neutral pelvic position and then kind of taking it back to your initial point, Ken.
01:21:09
Speaker
Now, when we when we think about this distribution of tension throughout the pelvic cavity, So posteriorly tilt your athletes, like have them actually mechanically do that and work on that. A lot of young kids live in that anterior pelvic realm.
01:21:25
Speaker
So if we get them to posteriorly tilt, we were talking about the importance of the hamstring being able to work as a flexor. Well, it's also a posterior pelvic tilter. So we
Hip Torque and Force Generation
01:21:36
Speaker
need to flex the knee, but then we also need to posteriorly tilt the pelvis. And we can do that in a number of different ways. But I think just from a cueing and from a positioning standpoint in whatever the exercise is, we need to be mindful of that as well.
01:21:51
Speaker
I did not know. This is ignorant. I did not know that it aids in posterior tilts in the pelvis. we'll We'll have that talk later today. Yeah. and can you Why didn't you not teach me that?
01:22:07
Speaker
um all right so we're we're like an hour 25 in and uh there i missed one piece and it kind of ties all this together as we talked about team sport athletes track athletes talked about acceleration talked about max v we did not talk about hip tort and the bridge between acceleration and max v dr ken do you want to you want to take that one i would I would love to. Yeah. So it's kind of been just, ah you know, involving thought process again over the last couple of years as to, you know,
01:22:39
Speaker
um what is driving the bus at the top of the chain? And I like all of Danny's comments regarding the foot, you know, during ground contact. I think that certainly can be a, an area that needs to be addressed ah first in a lot of cases where I've kind of focused with our research over the last three to five years is saying, okay, there's, there's certain athletes that can hit big ranges in top speed and they can do it with pretty good frequencies. I mean, if you look at any of our, you know, Olympic sprinters, we'll come back to maybe team sport athletes in a minute, but looking at the big sprinters, they got a lot going, right, of course, but they're hitting big splits and they're going through it and pretty big, you know, ah pretty fast frequencies.
01:23:23
Speaker
Well, That requires a lot of torque to drive that rotational motion. that's That's really what we're talking about when you're talking about does an athlete have fast frequency.
01:23:34
Speaker
It's do they have a lot of t torque at the hip that can drive those levers through a rotary motion. And I always like to bring up this example. and I know we're running short on time, but this is as an extreme example. Usain Bolt was 6'5", and he's the fastest human of all time.
01:23:48
Speaker
And everyone always says, oh, well, he was just fast because he had long legs. Well, and because he could apply force. Well, shit. Oh, pardon my language. Shoot. It's all good. Like six and could apply a lot of force. So why wasn't he the world's fastest man?
01:24:03
Speaker
Right? I mean, Jordan could apply all sorts of force. You ever look at him jump and he's taller than Bolt. Why isn't Yao Ming the world's fastest? Well, they couldn't turn the the wheels like Bolt could.
01:24:14
Speaker
Well, what does it require to drive long levers through fast frequencies? Torque. And what's driving that? Well, it's the torque at the hip, especially if you're looking at top speed. And what did Bolt have that no one else in the history of humankind have is that 12.3 meters per second at six foot five And if anyone else could do that at that height, that would require that sort of torque to have the angular velocity with long levers. But no one else has that. So that's kind of where that thought process started.
01:24:42
Speaker
But then if you look at the acceleration phase, yeah, there's a lot of things that are different. Acceleration to top speed, clearly, from a body angle to the ground forces, et cetera. But they are still working through pretty similar phases.
01:24:55
Speaker
splits, if you just turn the body on an angle, if you look at that thigh split, the actual front leg to back leg thigh split isn't that much different. And actually the frequencies are pretty similar if you look at step three onwards.
01:25:08
Speaker
ah A counterintuitive fact is that athletes hit more than 95% of their top frequency by the third step in a sprint. So what that tells me is they're going through this pretty similar range of motion. They're going at it at a similar frequency, whether you're at step three or step 33.
01:25:25
Speaker
So that means that the athletes that can do it at top speed and can also do it at acceleration, well, what's driving that bus? And for me, that that is the torque that's coming from the head. Now, to Danny's point about the foot, which I love and I think are highly accurate,
01:25:39
Speaker
If you have a foot that can't act effectively during ground contact phase, that is potentially a huge limiter. That's a huge limiter. If that foot ground interface isn't managed correctly, et cetera, then there's issues that can occur from the from the bottom up, to be sure.
01:25:54
Speaker
But I've always kind of looked at that Usain Bolt, michael Michael Jordan, you know, hypothetical question and said, well, something's making Bolt the world's fastest man at six foot five. And, you know,
01:26:06
Speaker
He didn't have the world's best frequency, but he could still spin the wheels at 4.4 or 4.5 steps per second. There's not a lot of other guys who are 6'5 that can do that or else we'd see them in the Olympics.
01:26:17
Speaker
And, you know, there's only one thing from a mechanical standpoint, you know, that could do that. So that's where that's where kind of some of those thoughts with hip torque have come into play. And, you know what's interesting and and, you know, I think talking about hip extension and the primacy of that, I mean, that is what's driving hip extension, right?
01:26:33
Speaker
I mean, it's a rotary force at the hip in just very basic terms that's driving hip extension. Now it's married up hip extension and flexion patterns. You could think of it in either way, you know, just from a 10,000 foot U conceptual level, it's a – It's a torque that's a happening you know with a a hip extension and a hip flexion torque.
01:26:53
Speaker
But the bottom line is the force that's going through the ground is to a large degree a result of the torque at the hip. So I i've i had a presentation that I gave for one of the other groups that I consult for last year that was titled Torque at the Hip, Force at the Ground.
01:27:07
Speaker
And that's kind of my most recent thought process of just a 10,000-foot view of what the causes and effects are. which I guess is a nice bookend to the first question you asked me last at the beginning of this, which is what makes fast people fast.
01:27:20
Speaker
And I think it's, it's really those two things, you know, just from a general explanatory standpoint, you got to have that torque at the hip and that's got to be translated into force at the ground.
01:27:31
Speaker
And, you know, I think that's an, it's an interesting way of, of thinking about it. Um, Yeah, I love that. it It reminds me of Alex and Tara's research where he's talked about the hip ISO being your force generator.
01:27:44
Speaker
Like if you're not good at that, then you're probably going to struggle generating force and generating force and extension specifically. And then the the ankle is the opposite end. It's a force transmitter.
01:27:54
Speaker
but bar viewer Or if you were to look at like a drop drop or something else, like how do you transmit that force? to the ground. So easy tests that we do every combine is we do the hip ISO, we do the ankle ISO.
01:28:06
Speaker
We've done the knee as well, so don't discount that. But you You have certain athletes, especially the ground-based ones, like the spinners and the drivers that are more ground-based and ground and step length-based, ground and strike frequency-based, but they have these really strong hip bisos, but they struggle at the foot, the transmitter.
01:28:25
Speaker
And that's where Danny comes in and he's been able to to to strengthen and and put the whole foot together so that we can start to transmit more force to that foot. Because typically it's not just...
01:28:38
Speaker
a physical quality they were trying to develop, usually there's a problem. And then we you figure out that problem and solve it. So yeah it's been super interesting to see both sides of that. And your research has really helped me understand like how a six foot five athlete needs to have high frequency, but he doesn't need to have five necessarily.
01:28:57
Speaker
Right. And then a five foot six guy does need to be closer to that five. yeah You have because there's, there's a limit. There's a limit to the amount of frequency we can produce as humans.
01:29:08
Speaker
Yeah, no, there is. And that's why you nailed And just one final point on that. Exactly. And if you think about shorter levers on a five foot six guy spinning faster, that's go to have a certain level of torque that's going to be conceptually similar to a guy who's got longer levers and spinning them slightly slower. Right. But those guys are all going to super high levels of torque. And.
01:29:27
Speaker
And then just kind of going back to one thing you said last, and I think JB Marin said this at one point, we've both probably been influenced, but yeah the, yeah, the force generation versus the force transmission. I mean, I just love that. Right.
01:29:38
Speaker
So, you know, that whether it's torque at the hip and force at the ground or whatever, just generation of force up the chain and transmission of force down the chain, all all of that, I think is a great way of kind of conceptualizing it. And and so I think, you know, ah very accurate, I think from from my standpoint as well.
01:29:56
Speaker
so
Conclusion and Final Thoughts
01:29:57
Speaker
hundred percent Well, I've ah've brought both your york times almost two hours now because we had a little talk before this. So I owe you your day back. But is there anything else you want to leave people with? A thought, something to read, anything?
01:30:14
Speaker
No, I just want to say thank you to both of you guys for having me on and, uh, and talking shop. And I mean, I could talk speed all day. What it was, it's 2 PM Eastern time. Let's go another 10 hours, but no, don't do that.
01:30:25
Speaker
like Thanks for having me. It's been great. And, um, yeah, uh, appreciate the chance to speak with you guys today. Yeah. Thank you, bro. Appreciate you. Thank you. This was awesome.
01:30:35
Speaker
This was awesome, dude. This is the best. Appreciate you.