So my question is about early and late propulsion as it relates to the squat and the split squat. So from watching a couple of your videos, as far as I understand, in the beginning of the squat, at the top part of the squat, that will be late propulsion. And then the bottom part of the squat, there will be early propulsion. Correct. Right? And then, so, I guess, my question is, first of all, if somebody needs to get early propulsion and they don't have access to mid propulsion, there's no way you can put them at the bottom of the squat. They're not going to be able to get there. So the better duration will be a split squat.

So my question is about early and late propulsion as it relates to the squat and the split squat. From watching a couple of your videos, as far as I understand, in the beginning of the squat, at the top part of the squat, that will be late propulsion. And then the bottom part of the squat, there will be early propulsion. My question is, first of all, if somebody needs to get early propulsion and they don't have access to mid propulsion, there's no way you can put them at the bottom of the squat. They're not going to be able to get there. So the better duration will be a split squat.

Correct.

And then, so, I guess, my question is, first of all, if somebody needs to get early propulsion and they don't have access to mid propulsion, there's no way you can put them at the bottom of the squat. They're not going to be able to get there. So the better duration will be a split squat.

Okay, so let's be really clear about what we're describing when we're talking about the early and late representations of propulsion. Because people get distracted by extremities. So people will say, well, you have a contralateral gait pattern. Well, if you look at the arms and the legs, you're correct. But if we look at the axial skeleton, everything turns in the same direction. And so if we're just going to look at the pelvis, we'll look at the position of the sacrum. If I am in a position of early propulsion, that's a counter-nutated, externally rotated position, but it's the sacrum moving backwards on the ilium. This is the yielding action that I always talk about. This is the expansive strategy that's associated with the expansion of connective tissues as you make contact with the ground. So you have to have contact with the ground to be really, really good at this yielding action. So let's just say left foot forward on a split squat. Imagine I was stepping into a lunge, if I was stepping into a lunge where my foot has not touched the ground yet, I can push this forward, the ilium will push forward and it turns the sacrum away from the front foot. That's a late propulsive representation because the sacrum's turning away from the leg that I'm stepping with. As the foot touches the ground and I come down and I put that foot into an early propulsive position where the first metatarsal head starts to hit the ground, now this turns the other way. And this is the yielding action that we're talking about. So in a squat, there doesn't have to be the rotation associated with it that a split stance would. That's why it appears to be different, but we're still talking about the position of the sacrum. So as I initiate a squat, and people will say, well, it's early hip flexion, it must be early propulsion. It's like, no, because the sacral position is what determines what phase of propulsion that we're in. So as I initiate the squat, I am externally rotated, but I got both iliums pushing forward into external rotation in that position at the initiation of the squat. So it's still counter-nutation relative to the position of the ilium. It's still externally rotated relative to the position of the ilium, but it's overcoming in that position as I initiate the squat. When I get below the sticking point and I start to re-nutate or nutate, that's the sacrum moving backwards on the ilium, and that's why that would be the early propulsive strategy. So at the bottom of the squat, I need the yield. As I initiate the squat, I'm in the overcoming action of the connective tissues. The relative position of the sacrum and the ilium are the same, but the connective tissue behaviors are different. So that's the difference between early and late propulsion.

Early propulsion has a yielding action. Late propulsion has the overcoming action. So I'm storing energy at the bottom of a squat, and I release the energy at the top of the squat. If I'm stepping forward, I have stiff connective tissues as the leg is moving forward in the swing. As it hits the ground, I have to absorb the energy back into the connective tissues. That's the sacrum moving backwards on the ilium to create the yield and the energy storage action. Does that make sense?

Yeah, that makes perfect sense. Does that answer your question?

Yes, it does.

Basically, if we want early propulsion, you would go with a split squat because, in the top position, because of the rotational aspect of the pelvis, you get the early propulsion.

Correct, because I'm creating the rotation. That rotation allows me to be very selective. So I can put your left foot on the ground in a split squat and I can create an overcoming action, or I could turn the sacrum and create the yielding action. So that's not one or the other—it's how I am coaching and positioning people as they're moving through this glute stance orientation. So I can turn the sacrum away from the front leg and maintain that late propulsive strategy on the lead leg, or I can turn the sacrum into the lead leg. So when we were talking about the offset weight: if I have a left leg forward split squat and I put the weight in the right hand, that's going to help me capture the early propulsive strategy on that left side because the offset weight is going to turn the sacrum towards the lead leg. If I put the same side as the lead leg, it turns me away and now I create the overcoming action.

And then if you pull the front knee, so let's just say the left knee, if you pull it into yourself, that's turning the sacrum. So they'll also create a yielding, early propulsion type activity. And then pushing forward would do the opposite.

So you're, yes, I think you're on the right track. Finish your statement. I'm sorry. I didn't mean to interrupt.

So, because, so they'll also create a yielding, early propulsion type activity. And then pushing forward would do the opposite.

That is correct. There you go. So the thing that I want you to realize, and you're actually helping a lot of other people understand this by asking this question, the thing that I want you to realize is it's how you execute activity. It's not the activity that is fixed. Like there's not one way for me to perform a split stance activity. There's not one way for me to perform a bilateral symmetrical activity. I need to understand the mechanics of the axial skeleton as to how I'm queuing it to achieve the desired result.

Okay and then if we are, I guess I have a couple of questions on the specific. So the first one, if you're pulling your knee into yourself. You're turning the sacrum towards the front leg. Yeah. You turn it towards the front leg. You're creating a yielding strategy on the back. But I also heard you talk about if you pull the knee in, you're biceping yourself towards internal rotation.

Okay. So you're turning the sacrum towards the front leg.

Yeah. You turn it towards the front leg. You're creating a yielding strategy on the back. But I also heard you talk about if you pull the knee in, you're bicing yourself towards internal rotation.

Correct. So consider the position and the turns. I'll walk you through using the left side. We'll examine the sacral position. First, I push the ilium forward and turn the sacrum away. This establishes a late propulsive strategy on this side—ERD ileum and counter-neutated sacrum. This is my lead leg in the split squat. Then I begin turning the sacrum toward the ilium, which is an ERD position. As I continue turning the sacrum, it eventually faces more forward relative to the ilium, creating an internally rotated, exhaled pelvic position. If I keep turning the sacrum, it moves back on the ilium, initiating the yielding action. So the sacrum progresses through this sequence: an externally rotated position, moves toward internal rotation, then ER again depending on how far I turn it. The sacrum must always move through this sequence of events. Does that make sense?

So if I'm just performing a split squat and I'm doing it like the normal way, what's the normal way? So I'm not pushing my knee forward or actively pushing it forward or actively backwards.

So the lead side is in a late propulsive strategy.

Late propulsive strategy, because the pelvis is turned to the right.

Because the sacrum is turned to the right.

The sacrum is turned to the right.

Really specific, because we use the extremities to turn the sacrum. It's not about the pelvis per se. We say the pelvis sometimes, but let's be really specific about the sacrum for now so we don't create confusion. Okay, so the leg forward lead leg is left and the sacrum is turned to the right. So that's a late propulsive strategy.

Okay, then from that point I don't change anything and I go down into the split squat. My pelvis, I guess my sacrum is going to turn to the left as I'm going down and I'm going to go towards a nutated position, right? And then if I pull the knee forward, I'm going to start in a more right-oriented position. So I'm not going to hit that nutated position as much when I go down because I'm starting in a more rotated position.

You got it.

And then if I pull the knee forward, I'm going to start in a more right oriented position. So I'm not going to hit that mutated position as much when I go down because I'm starting in a more churned position.

So you use the right words. You said not as much. That's a key element because you're going to move in that direction because you've got to produce force. So if you're not going to get nutation as much, you still need to put force into the ground as you descend into the split squat. So if you don't get sufficient nutation of the sacrum, which is representative of your internal rotation capabilities, you're going to have to create a compensation to produce enough force into the ground. So we're going to see another IR strategy show up somewhere. So maybe the pelvis orients its entire position forward. Maybe we see an excessive pronation. Maybe we see a forward head. So again, this is why we see these compensatory strategies executed in the gym because people are still going to produce internal rotation. You have to. There's no way around it. You cannot produce force in these externally rotated positions. So that's why we see compensatory strategies. So you have just answered several questions for a lot of people because if I don't have internal rotation available to me, I will compensate. People say, well, why do you see the pelvis tilt forward? Why do they lack hip extension? Because these are all representative of people that are trying to produce force in an externally rotated pelvic position, but they're superimposing IR from somewhere else because it's not coming from the hip.

Does that make sense? Yes, yes. Great call. Thank you. Thank you for taking time on a Saturday morning to talk to me. You're very welcome, sir.

Have a great evening over there in Russia, okay? All right, bye. How about we talk about clenching your teeth and creating extension for performance? Good morning. Happy Tuesday. I have neuro coffee in hand and it is perfect. All right. It is Tuesday. Clinic day to day, so very, very busy. Got a lot to do before we roll into the clinic. So let's dig into today's Q&A. And today's Q&A is with Sarah, and I've known Sarah for a little while now. She actually went through the intensive, and so we communicate on a regular basis with ongoing communication in that regard. And finally got a chance to talk to her face-to-face, which is fun. And we talked a little bit about some issues associated with people that clench their teeth, especially at night and influence of guards and things like that. But then we went into a situation where you actually need to create what it would be considered traditional spinal extension for performance. So we were talking about gymnastics and a couple of other sports, but there are situations where we actually want to use these compensatory strategies for performance. And so we talked about how to create some of those situations. So this is a pretty interesting call. I'm sure you will enjoy it. For those of you that would like to participate in a 15 minute consultation, just go to askbillhartmanedgmail.com, askbillhartmanedgmail.com, put in your request, throw me a question. and we'll get that arranged. We've got a few calls to get through yet, so there's a little bit of a backlog, so please be patient. Have a great Tuesday. Here's the call and I'll see you tomorrow. All right, we are recording. Sarah, what is your question?