The bilateral symmetrical stuff allows you to ramp up that force and that pressure because from an axial skeletal standpoint. We closed up shop on IFest 2.0. Everything is getting moved over to IFest 3.0. Training is up and running. Physical therapy should be up and running this week. I'm excited about that. I'm digging into today's Q&A. This is a question that Manuel initiated on one of the most recent Coffee and Coaches conference calls about force production on single leg relative motion in the pelvis and the influence of bilateral symmetrical activities. One of the things we're going to recognize is that things don't have to look exactly like something to have a favorable influence—for instance, bilateral symmetrical activities. High force producing activities are actually helpful in single leg activities. For example, we talked about agility in this call where the force is getting very, very high. There's a point in time where we want a reduction in relative motion within the axial skeleton for that high force production. This is where bilateral symmetrical activities come in handy because we don't have to worry about the turning that's associated with the control element of a single leg activity, so we can focus on that high force production that we're actually going to utilize in a single leg activity. As we move into a cut and that point in time where we need the highest force production to the ground, the least amount of relative motion gets closer and closer to what would be represented in the high force of that bilateral symmetrical activity. That's why they are useful. I think you'll find this call somewhat useful. If you would like to participate in a 15-minute consultation, please go to askbillhardmanedgmail.com, put '15-minute consultation' in the subject line, and we'll arrange that at our mutual convenience.

You know when we, so as we lift heavier and whatnot, we lose relative motion, or at least we don't want relative motion as much.

We're limiting it. Yes. We want to limit it.

In an example of, say, maybe a squat or a deadlift, are we more concerned with how the femur moves within the pelvis rather than the relative motion of the pelvis? Because when we talked last time, we discussed that during a single leg movement with one foot off the ground, you lock the pelvis into position and train how the femur moves within the pelvis. So I was just trying to connect those two concepts between lifting heavy and true single-legged work.

Yeah. And again, we have to consider the context. It's like the relative load that you're trying to move. So let's just say that we're really close to our peak capabilities. If I alter the shape of the pelvis as I am moving, it is changing. So that's the thing that we like, you know, if this is the full excursion of the pelvic shape change, I might be doing this. Which is one of the limitations of force output, by the way. So people that change shape a lot as they're moving weight don't lift a lot away because they can't maintain the force output. They can't maintain pressure. There's too much fluctuation in pressure. So the closer I get to peak output, the less motion I want because I need to maintain the pressure that provides me the force output. So the amount of relative motion in the pelvis has to be reduced to increase force production. For me to perform the activity itself, that hip joint has to move. For me to go down and pick up a bar off the floor and then to stand up with it, the hip joint's moving. And again, that's one of the limitations of picking the weight up. So those that can move the hip through a sufficient excursion to say that you're doing the lift, but yet still maintain the pressure via reduction of relative motions, they lift more weight. So you're gonna always move in that direction. And you can tell, you've done enough light squats versus heavy squats that you can tell that there's just a totally different sensation associated with max effort work compared to the lighter speed stuff or just a light warm up kind of a weight.

Right.

And you can tell because you can breathe, right? So we can go back to Andrew's question, you know, where we're talking about context, it's like, okay, let's just, let's just put, you know, 60 kilos on the bar versus, you know, 200. It's like your behavior has to change because the amount of pressure that you're creating is significantly different. Sure. So here, let me throw out a little bit of context, okay? When you're talking about cutting activities, like agility, a lot of people will say that you shouldn't use bilateral symmetrical lifts because you're pushing off of one leg when you're making a cut. And they say therefore single leg work is more specific. And I would argue that bilateral symmetrical activities magnify the pressure that's associated with your ability to hold a position, right? So that as you change direction, there's a point where you got to stop motion, right? Just like everything else. The bilateral symmetrical stuff allows you to ramp up that force and that pressure, because from an axial skeletal standpoint, same position. So there's value, there's tremendous value in high force bilateral symmetrical activities with less relative motion. Because when I got to stop motion under any circumstances, whether it's through a single leg or through two legs, I can take advantage of my shape changing capabilities to produce higher levels of force.

What about the reverse of that? So, for example, if you're doing a lot of bilateral activities, then what's the utility of doing true single-legged work? Or at least some people could say, yeah, who cares about your one-legged squat when you squat with two legs? You know what I mean?

Well, so again, it is different in regards to how you're going to be driving the force through the axial skeleton. So by saying that there's high force production with bilateral symmetry, it does not negate the value of being able to push through a single leg. What I'm saying is that when we talk about specificity, there are other elements of specificity. So ground contact through the single leg support is actually important because I need to orient over a single point of contact to produce that force. So again, there is value in that. It would be like saying, if you want to increase your agility, do back squats. And you could be right. But then to not do any agility at all and expect that to translate, it may not work. So there are elements, especially the turn that's associated with single leg. So when I'm bilateral symmetrical, okay, I don't have to worry about turning quite so much because of my ground contact helped me reduce that element. When I go to a single leg, as soon as I pick up that other foot, my body wants to start turning, right? And so I need to teach myself to resist that turn, thus the importance of the specificity of working on a single leg, right? So to move in and out of that, where I do need some relative motion, it may be who'd me to do both, right? Then again, what do I need them most? We'll provide the greatest benefit. If I had a thorax and a pelvis that were about the same width, so I'm built kind of like a refrigerator, it would be easier for me to stack weight on that than if I had a funnel that was sitting on top of a tiny little pelvis.

If you would like to participate in a 15-minute consultation, please go to askbillhartman at gmail.com, askbillhartman at gmail.com, put a 15-minute consultation in the subject line so I don't delete it. We'll arrange that at our mutual convenience. Everyone have an outstanding Tuesday and I will see you later.

My question is a bit more model-based, and I wanted to discuss some ideas I have regarding pressure and our water balloon or two-space representation. If I consider a vessel containing a certain amount of fluid—like a hydraulic ram—then a larger ram with more internal space can accommodate more fluid, creating greater pressure than a smaller one. Applying this to the body, is it feasible that one reason a muscle with greater volume can produce more force is due to having more volume to generate pressure from? Taking that further, if I had a water balloon and a basketball of the same size, they could technically hold the same volume, but their external containment—skin or connective tissue—would differ. I'm wondering if the model can provide insights into how this applies to connective tissue, such as how powerlifters or sprinters develop stiffer connective tissue over time, enabling them to impose more pressure effectively.

Go.

Taking that to the next sort of variable that I can see. If I had a water balloon and a basketball that were both of the same size, they would both technically contain the same amount, you could hold the same amount of volume within them. But the external, how was your point, the skin, what it's held together with is different on one than the other. Now wondering whether we can is there any inference that can be drawn by the model as to how that works with say connective tissue or something of that nature. To be able to impose more pressure so you got a power lifter or a sprinter or someone who is tissue is connective tissue stiffens over time. their ability to then impart that pressure obviously improves than someone of us trying to.

Did any of that kind of flow together as far as- Yeah, so which would be easier to stand on the basketball or the balloon?

Well, if you didn't want it to give way underneath you, you can stand on the basketball.

Right, so what representation do you want in regards to your force production?

Yeah, well the basketball, you want something with it.

Hang on, let me help here. Let's just say you had enough flexibility in the basketball that you could grab it and elongate it a little bit, okay? All right, you can follow from me so far. You take the balloon and stretch the balloon, okay? And then you let go. Which one's going to be faster?

If you could grab it and let it go, it would put the water balloon.

So we're just talking connective tissue stiffness now, aren't we? You see the difference?

Yeah, yeah, yeah.

So one isn't great for force production, but one is also great for speed versus the other one, right? Because it takes time for the deformation to occur. One deforms faster, so as it releases its energy, it does so at a higher rate. For instance, which one would you prefer to be snapped in the arm with—someone pulling back a basketball and releasing it, or the balloon? The one that snaps you fastest is the one that will hurt. Again, that's where yielding comes into play. This is why there's concern about secondary consequences in training. We can trace this back to the beginning of the call where we discussed distribution of resources. The question is: how stiff do we want this tissue to be? What's the optimum stiffness? For high-force production, it may be beneficial to be more stiff. For high-velocity production, it may be beneficial to be less stiff because we need the tissue to deform at a higher rate—that's what speed is. So the balloon represents a more yielding action, while the basketball represents a more stiff or overcoming action.

So with that, if the standard reason is that perhaps the reason you would see, say, a powerlifter of a similar weight to a bodybuilder, the bodybuilder may appear physically bigger, but the powerlifter would generally be, let's just generalize it and say that they're stronger—they can move more weight in a particular activity. Would that be just more down to movement efficiency, neural pathways, things of that nature, as opposed to their individual muscle properties? So if you were to group together a bunch of muscles that might be used, you know, bench press or squat, for instance, and test each muscle in isolation, chances are the bodybuilder might have a greater capacity to use the muscles individually. But the powerlifter, because of their practice, their neural pathways, the efficiency of the movement, they can move more load with those muscles put collectively together.

All right. So you're asking a question about a multifactorial process. All of those things matter, and then to whatever varying degree, right? Some can compensate for other elements.

Yeah.

So if you're a bodybuilder, would it? So you ever seen a Mr. Olympia with a 42 inch waist? A 42 inch waist. Yes sir, like 42 inches in circumference, like a big wide waist, big wide hip on an Olympia. Have you seen one? No. Why not? Because it's not pretty. It's not pretty. Right bodybuilding is a beauty contest, right essentially, and there are certain things that are aesthetically pleasing to the eye, right that are more representative of success in that environment. Power lifters would benefit more from a different structure. Right, so they look different and therefore they produce pressure in a different manner. I would also argue that when you get up into the higher classes of power lifters, they are equally as muscular as bodybuilders are but their physical structure is less pleasant. They're carrying a ton of muscle. They also might have a ton of body fat that goes with them because there's a benefit to that. So we can go right back to putting more stuff into a muscle creates more pressure. Well, guess what? If I jam more stuff into your belly, into abdominal body fat, I can compress that and it makes me more rigid and it allows me to lift heavier weights. Right? So again, multi-factorial process, but we're also dealing with structure. So under certain circumstances, if I had a thorax and a pelvis that were about the same width, so I'm built kind of like a refrigerator, it would be easier for me to stack weight on that than if I had a funnel that was sitting on top of a tiny little pelvis. Right? Now, if you go back and you watch the old Ronnie Coleman videos, he had the ability to sort of change shape a little bit under some heavier loads, right? So you watch him do the, you know, the 800 pounds squat. Have you ever seen that?

A 42 inch waist.

Yes sir, like 42 inches in circumference, like a big wide waist, big wide hip on an Olympia. Have you seen one? No. Why not? Because it's not pretty. It's not pretty. Right, bodybuilding is a beauty contest, essentially, and there are certain things that are aesthetically pleasing to the eye, right, that are more representative of success in that environment. Power lifters would benefit more from a different structure. Right, so, they look different and therefore they produce pressure in a different manner. I would also argue that when you get up into the higher classes of power lifters, they are equally as muscular as bodybuilders are but their physical structure is less pleasant. They're carrying a ton of muscle. They also might have a ton of body fat that goes with them because there's a benefit to that. So we can go right back to putting more stuff into a muscle creates more pressure. Well, guess what? If I jam more stuff into your belly, into abdominal body fat, I can compress that and it makes me more rigid and it allows me to lift heavier weights. Right? So again, multi-factorial process, but we're also dealing with structure. So under certain circumstances, if I had a thorax and a pelvis that were about the same width, so I'm built kind of like a refrigerator, it would be easier for me to stack weight on that than if I had a funnel that was sitting on top of a tiny little pelvis. Right? Now, if you go back and you watch the old Ronnie Coleman videos, He had the ability to sort of change shape a little bit under some heavier loads, right? So you watch him do the 800 pounds squat. Have you ever seen that?

Yeah, yeah, yeah.

Yeah. What, well, what was that? You gave me a peace sign or is that a two? No, because he did. Oh, he did double. Yeah, he did double. He paid the price for that one. But aside from that point. But again, it's like he was very, very wide as as a human being, but and again had enough structure that didn't really matter where he was capable of producing that type of pressure. Right. So again, you're looking at this from a multifactorial standpoint. But the rules are pretty straightforward. It's like he who produces most pressure wins as far as force production goes. So again, if I have a skeletal structure that allows higher force production, I can superimpose a ton of muscle mass on top of that. I can squeeze the bejesus out of it. I'm going to produce more force. Right. So the basic rule, even in the literature, you know, we go into the scientific literature and you look at the influence of cross-sectional area and force production, it stands to reason that the more cross-sectional area that I do have, my force production is higher.