I have a question about the seven components of force. The location of force. So the way that I've heard you describe it, if I'm not mistaken, we're usually talking about how force is distributed within the system. Are we mostly looking at it in terms of where the base of support is, or are we also thinking more globally in the body when we look at what the location is? And if so, could you elaborate on that a bit?

Okay. Header gut.

Header gut? Can you guys see that movie? That's Boy Scout, Bruce Willis, greatest actor of our time. Okay, quick story. Bruce Willis comes into his house. He finds his best friend with his wife, and he's very angry about that. And he sort of forgives his buddy, but he says, I can't let you walk away without punishment. So he goes head or gut, which means I'm going to punch you. You get to decide whether I hit you in the head or in the gut. Okay. So if I hit you in the head, right? That's location number one. There will be a wave when I punch you in the head that goes through your system from your head, you understand? Okay, if I punch you in the gut, there is a force that will be applied and it will move in a different direction, okay? Because of the location, because of the angle of attack, so to speak, the wave will propagate in a certain direction, okay? If you were to throw a punch, okay, you would pull force from the ground upward into your fist. And as you make contact, it would reverse gears and it would go the other way. Okay. And so based on the points of contact, that's going to determine where the wave would start and then what direction it can go. Does that, does that clarify?

Head or gut. Can you guys see that movie? That's Die Hard, Bruce Willis, greatest actor of our time. Okay, quick story. Bruce Willis comes into his house. He finds his best friend with his wife, and he's very angry about that. And he sort of forgives his buddy, but he says, I can't let you walk away without punishment. So he goes head or gut, which means I'm going to punch you. You get to decide whether I hit you in the head or in the gut. Okay. So if I hit you in the head, right? That's location number one. There will be a wave when I punch you in the head that goes through your system from your head, you understand? Okay. If I punch you in the gut, there is a force that will be applied and it will move in a different direction, okay? Because of the location, because of the angle of attack, so to speak, the wave will propagate in a certain direction, okay? If you were to throw a punch, okay, you would pull force from the ground upward into your fist. And as you make contact, it would reverse gears and it would go the other way. Okay. And so based on the points of contact, that's going to determine where the wave would start and then what direction it can go. Does that clarify?

It does. So in that description, at least the last one, it sounds like we're mainly thinking about where the force contacts the body.

So that's a big part of it, but now you have to kind of look at, okay, what is my physical shape? So if I was making a right foot cut, so I'm moving into the cut with my right foot, my foot hits the ground and that's going to perpetuate the vibration that comes off the ground through me. But it's going to hit different spots along the way based on shape. So as the wave comes up, it hits me in the knee. If I have a knee orientation in a certain direction, the knee could actually carry outside of my foot, which again, that's the location, it's hitting the knee in a certain shape, which will turn my knee in one direction or the other. In one case, I end up with an injury. In the other case, I create a wave that's going in the opposite direction that allows me to turn and come out of the cut.

Right.

Okay.

Right. Okay. So if we're looking at, just to make sure I kind of understand the base of support, the distributed versus local. So if I'm doing a squat with two legs, then because I have two feet on the ground, I'm going to get an automatic yielding bias of the connective tissues just because I have a wider base of support and I don't need to orient my body as much compared to a single leg squat where I would have to produce a pretty strong orientation towards that leg because I only have one base of support. Or is that too simplified?

So a bilateral support activity will have less rotation in it for sure. If you're bilateral symmetrical, is that what you mean? There will be less rotation to control. Now it doesn't mean you're actually going to turn in a single leg stance. It just means that you're going to have to increase the amount of muscle activity to apply force into the ground. Because again, it's dependent on how much turn that you want under those circumstances.

I'm trying to clarify the terminology regarding distributed versus local forces. There's clearly a force magnitude effect—for example, when using the same body weight in a bilateral squat versus a single leg squat, I'm loading roughly double the weight on my single leg. But if we were to equate the loads, how would I describe the difference in overcoming and yielding behaviors between the single leg and double leg squat?

So it would be mostly magnitude and rate. So higher magnitude is going to increase the degree of stiffness of connective tissues because the load would be instantaneous under those. So in both cases, you could have a magnitude that would promote a stiffness, an overcoming action of the connective tissues.

Yeah.

And in both cases, I can create a yielding action depending on again, load position, velocity that I'm moving. So again, you have an interaction that takes into consideration many of those elements of force production.

If I'm working on sprint acceleration and I do a forward sled push and then run right afterwards, I can immediately tell that my acceleration is much higher because the connective tissues have taken on a certain quality. And I've been able to do certain activities like cable chops where I'm looking to get hip internal rotation on a certain side and then successfully pair that with something where I need more dynamic internal rotation. I'm not just holding the chop. There's this effective duration on connective tissue behavior. And so that's a context that I've been able to use is where it's like I used duration holding like internal rotation to then do a dynamic behavior that requires that. What I don't understand maybe so much is understanding location in context of how I might use that variable to influence outcomes besides box squats. I use this all the time, but maybe I'm just thinking about it too theoretically and not.

Yup.

And so there's this effective duration on the connective tissue behavior. Yeah, okay. And so that's a context that I've been able to use is where it's like I used duration holding like internal rotation to then do a dynamic behavior that requires that I guess what, yeah, what I don't understand maybe so much is understanding location in context of how I might, um, use that variable to influence outcomes besides box squats. I use this all the time, but maybe I'm just thinking about it too theoretically and not.

Well, I don't mind theoretical, you know, thought that that's very useful. You're going to, when you're in an upright atmosphere, everything's working together. You understand that, right? Okay. Your points of contact are going to assure, though, that you're able to access certain aspects of movement. So if you were to do a cable chop with the weight on the outside edge of your foot, okay. All right. Less relative motion there. You understand that? You put your medial contacts down, okay, and you're going to be able to capture more relative motion. Okay, so you do that first, that's what you're saying, correct? Okay, so you're training the system to access certain aspects that will allow you relative movement. And then you're going to try to transfer that concept into another activity that is adding to the force production, right? So more velocity, for instance, more force. I have no issues with that whatsoever. I think it's a great strategy. It doesn't always work, but it does work. Okay. The reason I made, when I made my little smirk, when you said, when you said you got faster after the sled pushes.

Yeah.

Okay. You put your medial contacts down. Okay. And you're going to be able to capture more relative motion. Okay, so you do that first, that's what you're saying, correct? Okay, so you're training the system to access certain aspects that will allow you relative movement. And then you're going to try to transfer that concept into another activity that is adding to the force production, right? So more velocity, for instance, more force. I have no issues with that whatsoever. I think it's a great strategy. It doesn't always work, but it does work. Okay. The reason I made, when I made my little smirk, when you said, when you said you got faster after the sled pushes.

More acceleration.

Yeah. You got to be careful there because sometimes it's just perceptual. It seems like you're faster, but you're not really fast. Okay.

Okay.

But as far as conceptually, you're promoting positions that are similar. That may allow you to transfer the access to relative motion to another activity. Which, again, I'm fine with, but you do have to understand that when there's another element of force such as magnitude or velocity that you're adding, you are affecting the differences in connected tissues. Because you've altered rate of loading. That's a biggie. You've altered the magnitude and then you've also altered the frequency of loading. But you have to take all of those things into consideration. You say, oh, this is the same. Well, it's not the same, but it's similar.

Right.

So your body position when you're doing your slide push is very similar to an accelerated position. But the magnitude and the duration are a little bit different. Locations may be very, very similar. And so then it becomes very, very useful.

Right. Yeah.

OK.

Yeah.

So look at the concept of dynamic correspondence. This concept comes from way back before you were born. What it does is it's kind of talking about this: here's what we don't want to do. We don't want to necessarily try to duplicate an activity in another environment because then it doesn't really work. But there are certain similarities. There are positions where you would apply a higher magnitude of force. There are positions where the location would be the same. There are positions where the duration would be the same. Each time you match up some of those elements, then there is something that is useful that will transfer from one activity to another. Just because it looks the same doesn't guarantee that it's going to work.