So my question was regarding foot force production we talked about before, but I was confused when it comes to sprinting, where they tell you that your toes are always on the ground and your heel never touches, but that seems like you're still producing max force.

If we did not have the connective tissue behaviors, we would not be able to do anything. We would be like boneless chickens. It is Intensive Week. Intensive 12 starts Thursday. I'm very excited. We haven't done one of these in a long time. Looking to shake off the ring rust and have a great time with this group. They have done all of their preparatory work so they are going to be ready to go. By the way, we've selected the Intensive 13 people for July. Had to go to an alternate this time so this happens on occasion where somebody gets selected and they eventually can't come so we had to replace them. So that's exciting for our first alternate. I know he's excited about it. Today's Q&A is with Clint, my martial arts instructor. Clint is trying to refine his teaching method and his technique. We were talking about how we produce forces for striking and things. We got into a really good discussion, so I said, hey, we have to record this, because it's going to be useful for a lot of people because it's a great review. As we looked at the propulsive phase through the foot, we talked about how connective tissues are utilized for force production. Again, a lot of great topics, great review, so I think you'll find this useful.

So my question was regarding foot force production we talked about before, but I was confused when it comes to sprinting, where they tell you that your toes are always on the ground and your heel never touches, but that seems like you're still producing max force.

Okay. All right. So we've got three phases of the propulsive action that takes place. If we were just talking about walking, you would have the heel strike, right? And then you go to foot flat. So there's three rockers that we talked about. So we talked about a heel rocker, we talked about an ankle rocker, and then we talked about a toe rocker. So I take those three phases and look at that as an early representation of propulsion, which is for the sake of argument and the people watching, this is an externally rotated position as we go through the ankle rocker. So this is where you would experience most of what we would refer to as pronation. And so that ankle rocker is the middle phase of propulsion now. The end is late where the heel is actually off the ground. But where the maximum force is produced, the forefoot is still down on the ground in its most internally rotated position. So this is most pronated position. Release of maximum force. So what we have is we have this energy storage phase where we go from early through the middle phase, all the connective tissues are stretched. So it's like Wiley Coyote pulling back the big acne rubber band. Got it. And then he releases the rubber band. And so that's the point of maximum force, but that's what the heel brings from the ground. There's actually some really cool research that just came out recently that they were looking at the connective tissues on the bottom of the foot.

foot.

And they actually measured this. And there's actually this tiny little face, and I've been talking about this for a while and I call it maximum propulsion, which is where the release of the force actually takes place. It's when the heel actually breaks from the ground. So we're thinking about sprinting, or if you think about footwork associated with combat is moving around. Yeah. So, so, so the heel doesn't actually have to touch the ground. It's actually just the position of the release of force. But if I come from a position where my foot is grounded, it's going to be when the heel immediately breaks from the ground. So you're going to go through this middle propulsive phase. So if I was going to deliver a strike of any kind, where I have to take force from the ground, I'm going to be pushing through the medial heel. I'm going to be pushing through that first, the first metatarsal head. So right behind the big toe. and there's the heel breaks from the ground. maximum release of energy.

Okay. So if I'm coming down where I would be a sprinter when I'm coming down and basically a four foot strength where the heel never really touches the ground, but it gets really close. And it's the same place. Okay. If I was if my heel was coming up off the ground where I loaded the the heel. Okay. It's gonna be when I hit the heel breaks from the ground as I'm coming down. It's the exact same place. Okay. So it's still mimicking the same action. Yeah, because the forefoot grounded force producing position. Okay, that's when the heel breaks from the ground that that actually takes place.

Okay. So if I'm coming down where I would be a sprinter when I'm coming down and basically a forefoot strength position where the heel never really touches the ground, but it gets really close. And it's the same place. Okay. If my heel was coming up off the ground where I loaded the heel. Okay. It's gonna be when the heel breaks from the ground as I'm coming down. It's the exact same place. Okay. So it's still mimicking the same action. Yeah, because the forefoot grounded force producing position. Okay, that's when the heel breaks from the ground that that actually takes place.

So are those early and mid stages then very, very short? You're just reducing the time that those are expressed.

A sprinter's ground contact time, like at the highest possible levels, is between 0.1 and 0.2 seconds. It's like they're ticking so fast. But, so again, as a martial artist, a punch is delivered at about 1,200 degrees per second, which is still really fast. So it's like spinning your arm around in a circle four times in a second. That's how fast a punch is. So you think about, and again, I know you're not a big fan, look at the one inch punch concept. No, but yes. But what he's actually doing is he's using that concept to deliver the force production. So there's that brief moment where there's that load. It's like a sprinter's contact to the ground where he is stretching the connective tissues, they store the energy and then they release it and it's translated into the punch itself. I know the concept is kind of funny, but the reality is that's how force is delivered. It's the load of the connective tissue, so the connective tissues expand, they yield, they overcome as they release their energy, and that's why you get the force pushing. Muscles can't do that.

Can muscles are just, they're not a slap really.

Well, muscles are tuners. So what they do is they tune the connective tissues to behave a certain way. So if I contract a muscle, I'm actually affecting its connection to the connective tissues. All muscles connect through connective tissues. So it's the connective tissues that store and release the energy that we see demonstrated. Muscles by themselves are really not great at the velocity-based, force-based stuff. It's the storage and release of energy in the connective tissues, including your skeleton. So when we're talking about the heaviest loads possible, like a powerlifter or whatever, they actually use their skeleton to store and release energy. Okay, which is incredibly powerful because you think about like a bone would be like the stiffest possible rubber band, sure, versus like a skinny, thin rubber band. Like the skinny ones are fast. They snap. But if I can pull a really thick rubber band to the same distance as a skinny one and release that, that's a ton of energy. So the bones are kind of like that.

That's like when those high force production things, people tend to rupture connective tissues versus muscles, because they're the ones expressing that.

It all depends on the rate of loading that's going to determine how connective tissues behave, whether they behave stiff or whether they're more elastic. That's how you break up bone versus sprain an alligament versus tear an attendant. Like whatever becomes the stiffest at that moment in time absorbs most of the energy and then it has a certain tolerance to load where it becomes elastic and then once you hit the plastic phase and you go past this like pow then you get the break.

It's like a non-nitrogen fluid then.

Kind of.

Yes.

Like silly putty. Yes, it's okay. So silly putty all the time is a representation because if you pull it slowly it stretches and if you pull it fast it breaks, and that's literally how every tissue in your body behaves. Every single tissue. Yes. Because you're mostly connective tissue. Outside of the water, you're mostly connective tissues. Okay. And then you get some other stuff, like you get specialized cells, which muscle cells are specialized cells, liver cells are specialized cells.

Okay.

Because you're mostly connective tissue. Outside of the water, you're mostly connective tissues. Okay. And then you get some other stuff like you get specialized cells, which like muscle cells are specialized cells, liver cells are specialized cells.

But you're mostly connective tissue for a reason. And so that's really what's driving the majority of force production and force velocity.

Everything we've demonstrated shows that if we didn't have the connective tissue behaviors, we would not be able to do anything. We'd be like boneless chickens.

Okay. Interesting. Yeah. And then can I go back to really quickly the skeleton thing? So that has potential to drive force and power as well.

So a sprinter, if you didn't have the stiffness of the skeleton, they would not be able to bounce across the ground the way they do.

Because that sort of relates to how we talk about delivering power and punches. Try not to focus so much on moving the mass of the fists, say, but more on waving the energy up from the ground into the target.

A thousand percent. There's only one way that you can transfer energy without moving mass, and that's through wave behavior. So there's a vibration that comes up from the ground and translates through your body into whatever you're making contact with. Whether we're talking about throwing a baseball, throwing a punch, throwing a kick.

And that is predominantly done through your connective tissues. Muscles are just tuning.

Exactly. So if a muscle contracts really, really fast, the connective tissues that it's attached to have to create some measure of behavior. So if it's really, really fast, I can make a tendon very, very stiff or I can make a tendon stretch very easily. So if I apply slow tension, right? It's just like silly putty. If I apply slow tension to a connective tissue, it will easily elongate to whatever its capabilities are. If I pull it really, really fast, it resists and it becomes very, very stiff. But it still stretches and it still releases energy. It stores energy based on that behavior. So again, it's like muscles are tuners. They're not great at doing a whole lot of things other than tuning.

Interesting. Yes.

The opposite of what everybody thinks is that one way is that you lift things with muscles because that's what we see. It's easier to see muscles than it is to sort of see the tendon behavior or fascial behavior. But it's like there's no way to take the muscle away from everything and just watch it behave and then say, well why is it connected to all of these connective tissues? Yeah, well because that's what produces the force. That's what's elongating and I mean walking is incredibly efficient. It's very low energy because it's mostly connective tissue behavior. It's like the muscles turn on and off to tune these things so that the connective tissues behave at the right time so they can dampen forces or create stiffness when I need more force. Okay, right? So there's like a point in every step that you take where there's a maximum force into the ground and you have to be like and it's literally like a jolt. And so that's what continues to propel me forward. But then I have all of these connective tissues throughout my entire body that dampen the wave behavior that allows it to look very smooth. Otherwise your head would be snapped around and your vision would be so blurry. Yeah, so there's a lot of cool stuff about connective tissues in regards to the behavior and dampening protection, you name it. Yeah, it's pretty cool. And it doesn't rely on the nervous system. So it's fast. It's like instantaneous because the nervous system, even though the nervous system is very fast, takes like 300 milliseconds when you step your toe to get to your brain and you go, because you ever step your toe? You step your toe and you go, oh this is going to hurt.