THPStrength

Isaiah: 00:00

What's up guys? Welcome to the THP Strength podcast. My name is Isaiah Rivera. I have a 50.5 inch vertical, which is the highest officially recorded vertical in the world. This is my coach, John Evans, who also has a 40 plus inch vertical.

Isaiah: 00:12

And today, we are going to be talking about how to use your tendons to literally slingshot you into space. Alright. We're gonna talk to you about the science behind muscle contractions and their role in the stress shortening cycle. What is the stress shortening cycle? It's gonna be a lot of fun stuff.

Isaiah: 00:29

We're gonna start from basics all the way to the most complex topics, which is what this is for, to help you visualize all that. I know we've covered this in the past and it's really hard to wrap your head around, but seeing it visually can be really helpful. But, before we get into that, I want to give a quick shout out to our sponsors at thbstrength.com. If you want to jump higher and get rid of knee pain, go over there and check it out. They have a really good deal going on at the moment.

Isaiah: 00:56

Prices are going to increase dramatically in the future based on demand. So, if you want to get in early and lock in your price, go to thpstrength.com and sign up.

John: 01:04

I'm going fix this for you.

Isaiah: 01:05

There you go. Also, use the code THP for 10 off your first month. Without further ado, let's get into it. Where should we start? What's the absolute Oh,

John: 01:15

fundamentals. Alright. We need to understand what an agonist is, an antagonist, then the three different types of muscle contractions. I think that's, and then a muscle attendance unit. Yeah.

John: 01:25

So, the first thing we're gonna talk about is an agonist. So, agonist is spelled a, oh, that wasn't, Agonist, and this is a prime mover. That means that it is the thing that is working, the muscle that is working across the three, one of the three different muscle contractions. Right? So, you have a, we'll just say prime mover.

John: 01:49

And then we have an antagonist, which is basically the muscle that is not working. Yesterday, we talked about this a little bit with the tib anterior. So, I would say this is the, how would you word this? Maybe the

Isaiah: 02:05

Let's use a bicep. A bicep I mean, it would

John: 02:08

be the tricep in that scenario, but what would you say, the muscle on the opposing side of the prime mover? Yeah.

Isaiah: 02:14

Alright.

John: 02:17

And, this is important because Muscle opposing agonist. Oh, that's good. I don't know how you spell that. It two

Isaiah: 02:27

p's? Opposing. Yeah, two p's. Alright.

John: 02:31

Oh, I love whiteboards. This is so nice.

Isaiah: 02:33

Might be better for you to stand on this side, actually.

John: 02:34

Yeah, I agree.

Isaiah: 02:35

They can see as

John: 02:36

you're Yeah, yeah, Hopefully, that's big enough. But, it says agonist is the prime mover, and then antagonist is the muscle opposing the agonist. And we should talk about concentric and eccentric. Eccentric. Right?

John: 02:51

So, are three types of muscle contractions. There is a concentric contraction. So, but, C O con centric. I'm gonna go all caps. I think it'll be easier to see.

John: 03:05

Yeah. And that just means the muscle is shortening. Under tension. And then we have isometric. So, iso means same.

John: 03:18

Metric is length. Damn, I really whatever. And then we have eccentric, which is ECC. And you'll usually see like, if you see these, you'll see CON for concentric, ISO for isometric, ECC for eccentric. And this is like basic one zero one anatomy, like applied anatomy basically.

John: 03:48

And this is when the muscle is lengthening. So those are really basic definitions that are really important to understanding what we're gonna cover. We use all of these concepts every single time that we train. I keep these in mind anytime I prescribe anything because the agonist is going to be the prime mover or the thing that is allowing you to propel yourself upwards into space, run faster, etcetera. In jumping, the prime movers are typically going to be the quads, the hips, and the calves.

John: 04:22

An easy way to figure this out is on the up phase of any exercise, the muscle that is shortening concentrically, that is the agonist. The antagonist is the muscle on the other side. So in jumping, on the up phase when you push up, if you're looking at the calf like we talked about yesterday, that is the agonist. Muscle The opposing the agonist, the antagonist, is the tibia anterior, which is why you actually want those muscles relaxed on the up phase. Because if they're contracting, then you're opposing the prime mover, which is the thing pushing you upwards.

John: 04:52

Some of the things?

Isaiah: 04:53

Something that's really interesting, if you guys know Stuart McGill, he analyzed Jordan Koganan in a lab, and he said the thing that he was like most elite at is the rate at which his muscles relaxed. The antagonist? Yeah.

John: 05:08

Yeah. So, they can function, and the reason these are important is they can function as like a co contractor, meaning that it's co as in two things on the other side of the muscle. So, if you're looking at, say, a bicep curl, we can we can look at that example. What a nice whiteboard. You mind holding that?

John: 05:25

You know what? Let's use some other colors here. What do we wanna draw? Or we'll just draw like this. Alright.

John: 05:32

And then there's the axis of rotation. Here's your forearm. Okay. This is going to be your hand holding a dumbbell. And, you know, this is your shoulder joint.

John: 05:43

Okay. So this is your elbow. Here's your shoulder joint. There's your hand. The, you know, let's say you're holding 20 kilograms.

John: 05:52

Okay. The bicep is going to be the agonist in this example. Right? That is here's the tendon coming up. Okay.

John: 06:01

And then we have the bicep, which originates over here. This is your bicep. Your tricep would be on the other side. It originates over here, comes down, and attaches to your olecranon process on your elbow. Right?

John: 06:18

So this is the tricep. This is the bicep. The bicep in this example is, let's say, you're just holding the dumbbell, it is functioning isometrically holding the same length under tension if you're just holding it. Right? This is the agonist.

John: 06:30

We'll put a. And this is the antagonist. I'll just put a n t right there. Right? Anything else you think I

Isaiah: 06:42

need to include here? No. Pretty good basic definition? Yeah.

John: 06:45

So, if this muscle were shortening and you're coming up, right, then that would mean that the insertion is moving towards the origin. This is the origin of a muscle. Anytime you're moving the lever system of the bones, the insertion is moving towards the origin. So, is the insertion down here. Alright.

John: 07:07

Pretty good? The last thing we need to find is, we got the eraser. I think I handed it to you. The last thing we need to find is what a musculotendinous unit is. MTU.

John: 07:18

The MTU. The MTU is exactly that. It is the musculotendinous unit. So musculotendinous unit. The reason this is important is because it makes up two things.

John: 07:37

The muscle and the tendon. Right? Those are the base words of that.

Isaiah: 07:40

What's a also, let's define a tendon.

John: 07:42

So a tendon is basically the connective tissue that comes off of the fascia, creates a collagenous collagenous tissue that is functional. It is a force transducer. It basically takes the force that the muscle applies, attaches to the bone, and it is able to move the lever system. It is able to stretch and store and release energy. Pretty good definition?

John: 08:07

Yeah. Alright. And then the muscle is obviously the contractile tissue. You have a shortening that happens or lengthening that happens. It's called cross bridge cross bridge theory.

John: 08:17

And, yeah, that's basically it. So, this is really important to understand this whole concept. It's a musculotendinous unit. So, there are we could look at a cheetah if we wanted or something else. I liked your leg example.

John: 08:29

That was a good example. So, in a very, very good jumper, someone that jumps really, really high, there is something really interesting that happens at the tendon. Right? So, if Isaiah is let's try to think of this. We wanna do touchdown, mid support, and push off?

John: 08:45

Yeah. Do we wanna use

Isaiah: 08:45

the Achilles or the quad? Whichever one's easier to draw. Or visually, you think the

John: 08:52

quad is.

Isaiah: 08:52

I think quad is like the most specific.

John: 08:54

That one should be pretty easy. So here, we have the quad. Right? We have the knee joint. Here's the tendon.

John: 09:02

Should I draw the tendon in a different color?

Isaiah: 09:03

Yeah. Yeah. Maybe blue. Blue would be it. Alright.

John: 09:06

You got me? Thanks, bro. Alright. Let's go with that. So, then we've got the tendon.

John: 09:13

Alright. And, this is going to be we'll say You know what

Isaiah: 09:19

you should do? Underline this in blue.

John: 09:22

Oh, wow. I could write it in blue. Yeah. That'd be crazy, bro.

Isaiah: 09:26

That picture is gonna be nice.

John: 09:27

Yeah, bro. Yeah, bro.

Isaiah: 09:29

Take a screenshot of this.

John: 09:35

Alright. Tenderness. And, this is going

Isaiah: 09:37

to be, we'll say Put the t in blue. You might be able to just draw over it.

John: 09:42

This is crazy though. I'm trying to think of the best way to do this. We need to do a touchdown. We need to do mid support, and then we need to do take off. Right?

John: 09:52

So, this is at this is going to be at can you hold my marker? Yeah. Got that side for me. So, this is at touchdown.

Isaiah: 10:01

And, to define that so, I'm gonna imagine this is my foot, and imagine I'm a one foot jumper. Touchdown is the first frame where my foot hits the ground on my plant leg. Mid support is basically when I'm full footed on the ground. And then toe off is right on the last frame that my foot is on the ground for. Is toe off technically the last frame, or is it the first frame in the air?

Isaiah: 10:28

Is

John: 10:28

the toe off, to me, is rate Right before

Isaiah: 10:32

it takes before the foot.

John: 10:33

The foot is the last frame where the foot is still on the ground. Yeah. To me. That would be my definition. We should probably actually draw this with the bones too.

John: 10:41

Think that would be good. Alright, hold this. I'm trying to think of how I wanna visually represent this. So, we need to do, we'll look at the quad in a two foot jump. Actually, we can do one foot jump.

John: 10:53

We can one foot jump.

Isaiah: 10:54

That'll be easier actually. It's easier.

John: 10:55

Yeah. Yeah. So let's go with the quad. So we have, you know, here's your this is gonna be touchdown, so your leg's basically completely straight. We have the quad like this.

John: 11:06

Here's your tendon. Here, you've got your little kneecap. Right? You've got your tendon coming down into the tibia. And I'll draw the bone in, I guess, blue.

Isaiah: 11:19

Wait, do tendon blue.

John: 11:20

Oh, yeah. Tenon blue. Oh, yeah. You're right. You're tendon is blue.

John: 11:25

We've got the bone in green. We've got the we'll draw the femur. Yeah. Here's your femur. I hope that's large enough over there to see, but I can check

Isaiah: 11:41

if you want.

John: 11:42

Yeah, can check There's it out your thing. Here's your tibia.

Isaiah: 11:53

I'm gonna zoom in. Okay. That's fine. Can you see my head still?

John: 11:56

Yep. Cool. Alright. So, and then this is gonna be your your foot. Alright.

John: 12:05

At touchdown. So, in this scenario, we are really interested in the muscular tennis unit, what it's doing muscularly, and then the distance. So, if we are looking at the distance, we are going to be looking at here to here. Right? And, we have this much of it being the tendon.

John: 12:22

So, this is one distance. And then, we have the muscle. Right? Which is the fascicle that is the contractile part being the other distance.

Isaiah: 12:30

Okay? Can I move it forward? Yeah. Yeah.

John: 12:33

You can do whatever you And need then, in the next frame, we're gonna have mid support. So, this is where the leg is flexing. Right? I'll try to draw this somewhat, you know, to scale, but it might not be perfect. So, have this happening here.

John: 12:51

And, this is where things get pretty interesting. So, we have the muscle again. Right? And we wanna draw do we wanna draw a good athlete or a bad athlete? Let's draw a good athlete.

John: 13:03

Yeah. Alright. So in a good athlete, this is what happens. The muscle gets very, very short, and the tendon, oh my god, gets really, really long. There's also another tendon here.

John: 13:22

Right? That's the patella. It goes like this, basically. That's the tendon. So in a good athlete, this happens.

John: 13:34

Oops. You got it? Alright. So oh, we can lock these. So now, there's something very interesting that's happened.

John: 13:46

Right? We see, actually, well, we can't really draw it super well because I'd have to do this. This full distance right here has gone up. Right? Because the musculotenus unit has lengthened.

John: 13:59

Because we're angulating at the knee joint, right, the quad is lengthening at the knee. Assume that you're at the hip, it's staying the same. Actually, we can just look at the vastus lateralis or vastus medialis or intermedius. Right? So, it originates over here.

John: 14:14

You're flexing the knee, so we know that it's lengthening, right, at the knee joint. And as a result, the muscular tendonis unit, which is, you know, both of these, it's this this whole thing. I would even even go as far as to say this. This whole thing is the MTU. Right?

John: 14:33

So in this case, the MTU has increased its distance. It's increased its length. So something is lengthening here. Right? We have two parts.

John: 14:44

We have the muscle and we have the tendon. So in this example, right, the tendon was once this long, and now I drew it as an extreme example. This is the tendon. Right? And then up here is the muscle.

John: 15:06

And then, we have the same thing over here. Right?

Isaiah: 15:09

Draw draw like this. Oh, go ahead. Make this a red line. Oh, you want that a red? A hole.

Isaiah: 15:15

Ho ho.

John: 15:16

Thanks thanks for being my creative director.

Isaiah: 15:19

I got you, man. What I'm here for.

John: 15:22

Alright. So, if you watch these just visually, you can tell that the muscle has shortened. Right? And, the tendon has lengthened.

Isaiah: 15:32

Alright. And, this is really freaking important because traditionally, where they're

John: 15:39

touchdown, this, because the MTU is lengthening, so oh my gosh, we've ruined our markers. So, the MTU lengthened. That is defined, remember when we said eccentric is what? Is lengthening. Right?

John: 15:59

The muscle's lengthening. Yeah. But when you're looking at the muscular tendons unit, or traditionally speaking, we just talk about the MTU as the fascicle, meaning the contractile part or the muscle. It's not necessarily true. But we see the MTU is lengthening, meaning it's eccentric.

John: 16:12

Okay? Or seemingly eccentric. However, when we compare these red lines, the red line got shorter, which means that the muscle is functioning concentrically.

Isaiah: 16:25

And that's why the tendon

John: 16:26

And the

Isaiah: 16:26

tendon

John: 16:26

is

Isaiah: 16:26

lengthening length because it's pulling it. That's how that's how the tendon lengthens.

John: 16:30

So, it could lengthen two ways. If this were if the muscle were to stay the same length, right, you could still have the tendon lengthen. It's just that if the muscle shortens, then you get even more lengthening, which is what you want, right? Because the MTU is gonna lengthen no matter what. Because you're doing an eccentric action.

Isaiah: 16:46

Can you go over that a little more? Would an eccentric, or an isometric muscle contraction

John: 16:52

Let's be lengthened that the, hypothetically, right, let's say that the muscle didn't change length. So, I'll go over here. This isn't drawn to scale. But, let's say, right, that the muscle stayed the same length. So, like, let's say there.

John: 17:11

Right, roughly? Yeah. Something like that? So let's draw the muscle belly like this. I've ruined our markers.

John: 17:19

Alright, so we can see, maybe let's see how I can draw this a little bit better. This isn't gonna be a good representation. Yeah. Maybe like that. Holy shit, that was a big lizard.

John: 17:33

Do see that thing? No. It was massive. Probably got alright. This is better.

John: 17:39

Yeah. Okay. So we have the MTU is lengthening. So, we know that this whole length got longer. Right?

John: 17:47

So, let's say that this is d one and this is d two for the MTU. So, we know that d two is greater than d one, meaning MTU d two is greater than m t or sorry. MTU d two maybe this is better. Two, is greater than MTU one. The muscular tendinous unit, this distance, is longer than this distance.

Isaiah: 18:16

It has to be. Remember, this is This is a

John: 18:19

This is a touchdown. So, touchdown, your foot hits the ground.

Isaiah: 18:21

They can't see the

John: 18:21

Oh, they can't see the ground.

Isaiah: 18:22

Use your foot. Use your foot.

John: 18:23

Your hand. So you hit the ground like this, and then you start to flex. Okay? Where you hit the ground like this, your knee starts to bend, so the muscular tennis unit has to lengthen. That will happen as a result.

John: 18:34

Okay? Because that happens, right, the muscle and the tendon are doing something interesting in a stretch shortening cycle. Right? With a stretch shortening cycle. Stretch shortening cycle is any time you have a muscle, muscular tennis unit, stretch very quickly followed by very quick shortening.

John: 18:52

So a jump, a sprint, anything else, that would be considered a stretch shortening cycle. Yep. So this happens, right, and now we have the muscle functioning and maintaining its length. So we know that the whole muscle of the tennis unit has lengthened, but the muscle, right, m one and m two are the same. So we know m one equals m two.

John: 19:15

The only way for this to occur whoops, sorry. The only way for this to occur is if the tendon lengthens. The tendon has to lengthen as a result, and you can see visually the tendon is longer. Obviously, I drew it that way, and so you're like, well, drew it that way. Of course, it's that way.

John: 19:31

This is what you would see in an actual representation of, like, a cheetah or a gazelle or something else. Now, what if and actually, here's Why maybe a better is why is it better that the tendon so we know that t two is greater than t one. That's the only way all these things could stay true. Now, at takeoff, why would it be good that the tendon is lengthening, right, more than what the muscle is, Isaiah? Why would you want the tendon to be as long as possible during a stretch?

Isaiah: 20:07

Because there's gonna be more energy stored. Because tendons

John: 20:10

are way way faster than muscles. They're way more efficient. They're way better at converting energy quickly. Right? A muscle contracts relatively slowly.

John: 20:21

If you were to, like as fast as possible without a stretch, try to contract it, it's not gonna be very quickly. Yeah. But if you take advantage of the tendon, you're able to get way way higher velocities of joint velocities, basically, which means that you're gonna propel your lever system, I. E. Your body, into space, your skeletal your skeletal system.

Isaiah: 20:41

That's the whole point of explaining this and understanding this is stretching the tendon is how you get elite performance. Is how

John: 20:50

Isaiah jumps 50 inches. That's how a cheetah runs fast.

Isaiah: 20:53

The difference between so, I would say an elite athlete can use a concentric muscle action here to stretch their tendon. You can still stretch a tendon with an isometric contraction, which is not as much, because there's still tension in the muscle, that's why it's stretching. And then a bad athlete doesn't even stretch the tendon. Right? They're not strong enough to stretch it.

John: 21:17

Yeah. Or, you know, in a bad athlete, what would happen is actually the muscle lengthens, and the tendon doesn't stretch at all. Right? So, a bad athlete would do this, and they would actually lose tension. Right?

John: 21:30

In the they would lose tension. The muscle lengthens. It actually gets longer. So, you know, it goes from maybe something like this, and then the tendon actually it actually shortens during, you know, the part where it should be stretching. Because a stretch shortening cycle would be the whole MTU.

John: 21:51

Right? So, you see this is, you know, normal length. It stretches here, and then you get a push off. That's a stretch shortening cycle. Conventionally, we would say, oh, well, the eccentric action's really important.

John: 22:02

That's where the stretching's happening. That's where you're storing all the energy. The better you store the energy, the higher you'll jump, the more efficient you are at that. The better you'll jump. The better the athlete are, the more explosive you are, the more you act like Russ and a kangaroo or a cheetah.

John: 22:13

So we would always say, well, the eccentric is what you need to train. Right? That's what we need to train, eccentric muscle actions. That's why we do really heavy lowers. That's why we do really heavy negatives and stuff like that, because we need to be really good at stopping momentum and storing energy and releasing it.

John: 22:27

However, that is not actually what happens in really good athletes. Really good athletes, we're gonna draw this over again. Go ahead, give me the we'll drew the Achilles. Right? Usain Bolt's Achilles.

John: 22:36

That's what we're gonna draw. If he were I'm just gonna use one marker here because this will be easier to faster to draw. Alright? So, if I'm drawing Usain Bolt, okay, and I'm looking at calf at touchdown, And, you know, here's his his foot or whatever else. Okay.

John: 22:54

Comes here. We got this massive Achilles, and he's got a ball of muscle, his calf up here, you know, and whatever else. Here's his knee up in this area. I'm just gonna erase all this so I can get all that in there.

Isaiah: 23:08

Alright? I have a I have a quick question. Yeah. Before before you draw this. Because I think something just clicked in my head.

Isaiah: 23:15

So, you're at mid support and then you keep pushing, right? We're looking at the quad.

John: 23:22

You're saying through from mid support to take off?

Isaiah: 23:25

Yeah. Yeah. And, we're yeah, like mid support to toe off, and we're looking at an elite athlete. I remember you said, what if an athlete is strong enough, concentrically Grab

John: 23:33

a rubber band.

Isaiah: 23:34

To Grab

John: 23:35

a rubber band.

Isaiah: 23:35

So so what if the athlete is strong enough to keep pushing and It continue stretching the just made sense to me. But, so you stretch it

John: 23:46

like this. If you stretch it like this, better yet, grab grab that weight right there. Grab that five pound weight. Alright. I'm gonna put

Isaiah: 23:54

these right here.

John: 23:55

See if I can explain this. This might be difficult. So, if I do this. Right? Is that gonna stay?

John: 24:01

That won't stay. Will? Yeah. Yeah. Alright.

John: 24:05

So, if I am holding this five pound weight, right, and I were to stretch

Isaiah: 24:09

it, okay,

John: 24:11

and I release it, it pulls back up. Right? The more I stretch it

Isaiah: 24:14

Yeah.

John: 24:14

The more it pulls back up. Okay? Now, hypothetically, let's say I did this. Okay? If I if I just hold isometrically, I get this much energy.

John: 24:25

Okay?

Isaiah: 24:25

Yeah.

John: 24:26

Now, if I actually let's say that my arm represents the muscle, This represents the tendon. This is your mass.

Isaiah: 24:34

Yeah. Okay? Yeah.

John: 24:35

So this is the Achilles, basically. Yeah. Right? This is this is my calf. I just drew it here.

John: 24:40

Here's the tendon. The more I stretch the tendon, the more energy I get out of it. Yeah. Okay? So if I do this, and then I touch down and I let off energy, I'm not gonna get a lot of energy.

John: 24:50

Yeah. The height this bounces represents how much energy I get out of the tendon.

Isaiah: 24:53

Yeah. How much

John: 24:53

push off you get. So if I do this, and then I'm strong enough, you know, I I touch down, the tendon starts to stretch, I'm in mid support, and then I pull even further.

Isaiah: 25:05

The tendon doesn't release energy until toe off?

John: 25:09

It won't release energy until the energy in that joint exceeds the the internal torque exceeds the external torque.

Isaiah: 25:18

Okay.

John: 25:19

Does that make sense?

Isaiah: 25:19

Yeah. Yeah.

John: 25:20

So, if the tendon like, you're gonna have to dissipate the energy at touchdown, and then eventually the energy is gonna build up enough where you take off. Right?

Isaiah: 25:28

So Yeah. Because I was I'm having a claw.

John: 25:30

This mass won't move until this tension exceeds the weight of this. Right? Yeah. So, this is at rest. So, at touchdown, what's happening is your mass is coming down, so it stretches the tendon.

John: 25:41

You know, if it if it's not enough force, like right here, that's not enough force to stretch anything. Right? Eventually, it's enough force to stretch something. Eventually, eventually, eventually, you know, the tendon exceeds if the muscle can keep pulling as the joint is pushing down and hold that, eventually the tendons are just gonna keep storing energy and have so much energy that it exceeds the external torque of your The internal torque exceeds it, and that mass will float

Isaiah: 26:07

off the The reason I was having a when you were first experiencing I'm

John: 26:10

glad we bought these rubber

Isaiah: 26:11

That's gonna be the thumbnail right there. Yeah. But, the reason I was having trouble understanding at first is I I had a there was something wrong in my logic. I was assuming

John: 26:21

Can you hear me that?

Isaiah: 26:22

Was assuming that Actually, it's fine. It's during the eccentric action, it was loading up and then mid support, the energy was getting released, and that's what was causing the shortening. But I didn't realize the tendon could keep lengthening Yeah. Through mid support It can go all the way all the way

John: 26:36

to toe off. Toe off. Yeah. Well, it could it it starts to shorten. It will start the tendon will start to release the energy.

John: 26:43

Like, this was shortening as I was pulling up. Right? Yeah. But, like, eventually, your foot's off the ground, and that's when you'll see the foot flick usually. Like, if you watch jumpers, like, jumpers

Isaiah: 26:52

Yeah.

John: 26:52

They'll store a ton of energy in their Achilles or, like, when you jump. If you've seen jumpers, they'll store a bunch of energy, and then you'll see the foot like flick off the ground Yeah. And go limp. That's because the tendon's releasing all the energy. Yeah.

John: 27:02

So in real this is a break, you can

Isaiah: 27:04

just keep yanking on that Just keep

John: 27:06

pulling and pulling and pulling. So, like Usain Bolt. Right? Here's his muscle, right, at a touchdown. Okay?

John: 27:13

So now if hypothetically, you know, we go to the next frame, I'll just draw it over here. So we're probably now as he's It's like okay, you can sneeze. So if he's here, here's his knee, we come down like this. Now his foot's in, you know, dorsiflexion or some dorsiflexion like this. And now his muscle is shortening even more.

John: 27:40

We gotta freaking belly that thing up. I shouldn't have drawn it like that, but it's okay. It's gotta be it's gotta be like like that. Okay? Let's even draw it like this.

John: 27:51

This will be good. It's not Usain Bolt. It's like me or you. We're normal mortals. Alright?

John: 27:58

So now let's say if his muscle is able to belly up and keep freaking keep freaking shortening, now look at this. Look how much energy that tendon is stretched to.

Isaiah: 28:09

So this is pre

John: 28:10

So this muscle is just shortening.

Isaiah: 28:12

That ground contact date here?

John: 28:13

This is prior to this is like, here's the ground. The ground is the ground's here. He's not touched the ground yet. He has now contacted the ground at this point.

Isaiah: 28:23

So it's pre contracting right here? It's a little.

John: 28:25

I mean, this is just the standard it will. Yeah. He will start to pre contract. Yes. But that's a different concept.

John: 28:31

But, yes, he will. For another reason. Yeah. So if he can start to contract even earlier, right, and that's where the tibialis anterior comes in because if it can co contract

Isaiah: 28:38

Yeah. It will help. Yeah.

John: 28:40

Which is very complex. I will not go into But this is where he will store a ton a ton of energy. If he can continue to pull, if that muscle can continue to pull, so if his Achilles was here, right, and then in

Isaiah: 28:54

this frame touchdown It's is like your muscles here? My muscles going.

John: 28:58

It's so, yeah. Like, here. Then I'm going. Pulling. So, now he's storing a ton of energy, and then a toe off, right, he can freaking, you know, here's the ground.

John: 29:08

He's now this is gonna be awkward to draw. Here's his foot. There's his big toe. He's like this. Misses toe off.

John: 29:17

Okay. So now at this point, everything is starting to to shorten. Right?

Isaiah: 29:21

Yeah.

John: 29:22

So we have the muscles here still. Here's the tendon. The MTU in general is relatively short. It's relatively short. But if that muscle could keep pulling during this phase, he's gonna keep he's gonna get even more energy out of the tendon.

John: 29:38

Right? Yeah. Even though the tendon started to the tendon has shortened. Right? So, it's relatively shorter here than it is here because it's released the energy.

John: 29:46

The tendon has finally done oh, what the heck? Oh, that was the mic. So, the tendon was, you know, it was here, and then it stretched, and then in this frame, it's now releasing that energy, and as a result, your foot is plantar friction.

Isaiah: 29:59

And the whole time, your calf is just shortening, if you're a good athlete. If you're

John: 30:02

a good athlete.

Isaiah: 30:02

You're good athlete the whole time.

John: 30:03

Like a cheetah or a gazelle, yeah. Now, if it stays the same length, which maybe is the next best thing, you know, it just stays the same length, but the tendon, you know, lengthens, right? So, I didn't draw this to scale, but, you know, if it stays the same length, okay, and the tendon, you know, in this example, you have to have a little bit more lengthening because the foot is, you know, in dorsiflexion. So as a result of dorsiflexion, you're going to, you know, you're going to have the tendon lengthen even if it is just a couple inches, right, in this scenario. So this joint angle was, you know, whatever, 90 degrees, and it went to 45.

John: 30:43

Because of that, this will stretch. The Achilles will stretch. Right? It'll store a bunch of energy, and then it push off. Even if it's the same length, Right?

John: 30:51

Let's say it was the same length the whole time. So, the tendon here was whatever. Let's say this is I don't know. This isn't drawn to scale, but it's actually not too bad. It's not good.

John: 31:06

Let's say this was like eight inches or something. Right? Yeah. Okay. In this example, the MTU lengthened, the muscle of tennis unit lengthened, and now the muscle is or let's say the MTU

Isaiah: 31:20

And this is an example, let's say, for like a good athlete.

John: 31:22

Fourteen inches. Like a good athlete. Not a great athlete, but like a good athlete. Let's say it was 14 inches. Yeah.

John: 31:27

Right? For the MTU. So, 14 minus eight gives us what is that? Six? Okay.

John: 31:33

So, let's say now the muscle stays isometric. So, the muscle's not gonna lengthen the whole time.

Isaiah: 31:38

This is prior to touchdown. We're at six and eight, right?

John: 31:41

Yep. Okay. This this is like right before touchdown. So, now we have touchdown through mid support. Now we know the MTU lengthened.

John: 31:48

Right? So now the MTU is let's say, I don't know, 16 inches. Okay? So that's again not perfect. I don't know if my lower leg is 16.

John: 31:56

Probably more like 24, but whatever. Just for the sake of math. This is a midget. I mean a little person. Alright.

John: 32:03

So so now we again, the muscle is the same length. So it's six inches. Okay? That's about six inches.

Isaiah: 32:11

Yeah. And we Actually, it might be.

John: 32:15

Yeah. That might be.

Isaiah: 32:16

I think that's pretty good. That's pretty good. Alright.

John: 32:19

So now, we know that, again, six minus now it's 10 inches.

Isaiah: 32:24

I wanna I wanna stop again. Because I

John: 32:26

The muscle has lengthened, or the tendon has lengthened two inches. It's stretched two inches. The muscle stayed the same length. The tendon lengthened So two inches.

Isaiah: 32:34

I wanna ask you a question. Yes. How the hell did the tendon lengthen, but the muscles stay the same length? Because don't you need to yank on the tendon? You've angulated.

Isaiah: 32:45

So, that's from dorsiflexion? Yeah. Dorsiflexion.

John: 32:48

Okay. The MTU lengthens because you've dorsiflexed. Like, you can't when you go into a stretch, if you stretch, the MTU is longer.

Isaiah: 32:58

Yeah.

John: 32:58

Right?

Isaiah: 32:59

Yeah. Yeah. Okay. Because you're going

John: 33:00

from here to MTU is its longest when you're in dorsiflexion like this.

Isaiah: 33:04

Yeah.

John: 33:04

And then, you plantar flex, the MTU's short. Right? The distance from here to here is shorter than it is from here to here. Gotcha. Right?

John: 33:10

So, now you're in dorsiflexion, that's why the MTU lengthens, because the joint is angulating. So, in this part, the MTU the shortest

Isaiah: 33:16

Is it possible to lengthen the tendon in an isometric contraction without moving the links? Oh, wait. What?

John: 33:26

So, you're saying Like, if

Isaiah: 33:27

this if, like, this is 90?

John: 33:29

Yeah.

Isaiah: 33:29

Let's say this is 45. You're, like, already So, you're, like, you're anchored in And then, you stay at 45?

John: 33:34

Yeah. It's possible. It's called a depth drop.

Isaiah: 33:36

But, how does that happen? Is it because it's a So, stronger isometric

John: 33:43

you would you're still gonna have lengthening at landing. It's not perfect. Yeah. Like, you're probably never gonna have okay. So, you're saying, is there a scenario where the muscle of tennis unit stays exactly the same.

John: 33:55

Right?

Isaiah: 33:57

No. No. No. No. Like, you still get tendon stretching.

Isaiah: 34:01

Is there a scenario where you have an isometric contraction and the tendon length increases without having to

John: 34:09

You have to have this happen.

Isaiah: 34:10

You have to have okay.

John: 34:10

You have to have angulation.

Isaiah: 34:11

Your limbs have to move

John: 34:12

in order to lengthen it. For the MT, the MTU has to change Gotcha. To any time you angulate, the muscular tennis unit is changing. That's how you move.

Isaiah: 34:23

But, there's more tension there. The lever,

John: 34:24

you wouldn't have a lever system in that case.

Isaiah: 34:26

Gotcha. Right? Yeah.

John: 34:27

The lever doesn't move if the MTU doesn't move.

Isaiah: 34:30

Okay.

John: 34:30

That's how it moves.

Isaiah: 34:31

Yeah.

John: 34:31

Does that make sense? Mhmm.

Isaiah: 34:33

But, you're still getting like, stronger asymmetric contracting here because it's lengthening while it's staying the same length.

John: 34:40

You're still getting, your force will go up a lot in this scenario, right? Yeah. It's just that it's not budging. Like, the force is going up, it's anchoring down, it's anchoring down. It's like a, hold this, Right?

John: 34:52

So, do your analogy again with your other hand. Okay. But it's staying here? It's staying here, but I'm still oh, come on. Don't let it this is actually what's happening.

John: 34:58

Okay. Okay. Your shoulder is isometrically mother So, if you can the force is going up really quick, but it's still isometric. Yeah. Now, do it again.

John: 35:05

Hold it again.

Isaiah: 35:06

But now, it'll go

John: 35:07

Now, go the other way. That takes even more strength.

Isaiah: 35:09

Now, you be a when you be a bad athlete. You're a bad athlete.

John: 35:12

Yeah. The tendon doesn't stretch at all. So, that's exactly what happens. So, in this scenario, you know, the MTU went from, let's say, it's the shortest it can possibly be. Let's say it's eight inches.

John: 35:24

Okay? So, now, we know that the muscle is still isometric.

Isaiah: 35:29

Right? Yeah.

John: 35:30

So, this would be six inches.

Isaiah: 35:33

So, that would be

John: 35:34

And, now, the tendon only can go

Isaiah: 35:36

six then you're going, phew.

John: 35:38

Yep. So, now the tendon is shortened. It's shortened all the way. I mean, this is not to scale, but conceptually, you can understand how that would work. Right?

John: 35:46

And, that's because the calcaneus has moved up. The insertion moved towards the origin. So, the MTU shortened.

Isaiah: 35:54

Alright, cool. I think this is a pretty yeah, I think this is a good understanding of what is happening in a jump, in a sprint. By the way, if I know a lot of you guys say, this content's too advanced for me. If you get confused at any point in this, drop a question.

John: 36:11

You probably have to watch this like four times in

Isaiah: 36:12

order Yeah. To But, the the only way to learn is to ask questions. Yeah. That's how I learned.

John: 36:16

Like, this is like explaining calc three. Yeah. You know? It's not this is not like explaining like, calc three is complex. Of

Isaiah: 36:22

jump training. The calc three of jump training.

John: 36:24

This is calc three of jump training. Like, it it it's gonna be complex. If you don't have any understanding of basic arithmetic

Isaiah: 36:31

Yeah.

John: 36:32

Yeah, this is gonna be really hard.

Isaiah: 36:33

If you don't even

John: 36:34

know what a concentric muscle contraction is, that's like that's like algebra, you know? If you don't know what a muscle is, that's like arithmetic.

Isaiah: 36:40

Yeah. Like So, I wanna get a little bit into the implications of training because what you're telling me, John, John, jump Einstein Evans. You're telling

John: 36:50

You me got the eraser? This this now, is now even what are the implications of this?

Isaiah: 36:57

You're telling me that in an elite athlete, is there an isometric or even a slow concentric muscle action happening, which isn't what the jump trainers on Instagram are telling me.

John: 37:09

So, wait. Say it again.

Isaiah: 37:10

You're telling me that in an elite and good athlete, you're seeing an isometric muscle contraction at the quad, and maybe even a

John: 37:19

A low, Yes. I am saying that if you want to stretch the tendon a shit ton, if your foot's on the ground for two hundred millis or a hundred and eighty milliseconds, right, if you can contract relatively at a hole, if you can contract an inch, if you can contract half an inch, you will store more energy in the tendon. The tendon will do all the work. The muscle is just an anchor. It's just there to anchor while you're the the force of your foot striking the ground or coming down is stretching everything, stretching the MTU, hopefully mostly the tendon if the muscle's really strong.

John: 37:51

So we've seen the force velocity curve. Right? So on this side No.

Isaiah: 37:55

I I haven't, John. Oh, you haven't? No. I've never seen it.

John: 37:58

You've never that is absolutely

Isaiah: 37:59

What is the force velocity curve?

John: 38:01

So, this is negative. What the freak is happening here? Oh, there we go. So, negative 360. This is zero degrees.

John: 38:09

Degrees per second. Degrees per second. So this is ISO. This is the MTU. This is a muscle.

John: 38:18

So a muscle fascicle. This is not looking in a stress shortening cycle. Just looking Right here, muscle fascicle. Muscle. Muscle.

John: 38:35

No. No. No. No. I think that's it.

John: 38:39

Right? Yeah. I think that's how you spell it. There's not two c's in there. Oh, who knows?

John: 38:42

I don't know. Not an English major.

Isaiah: 38:44

We're not Austin.

John: 38:45

That's what Austin's for. Alright. So, this is positive 360 degrees per second. Right? So, this is negative.

John: 38:55

This is eccentric.

Isaiah: 38:57

I think that does have

John: 38:58

a C. ISO. There's two Cs?

Isaiah: 39:01

I think it's like FS. It's like SC.

John: 39:05

Think that's what it FC?

Isaiah: 39:07

No. No. SC. SC. S c.

Isaiah: 39:11

Yeah. S c. That's There's

John: 39:13

two c's in fascicle?

Isaiah: 39:14

Yeah. Yeah. Big fascia. Like fascia.

John: 39:18

It's a silent c, Fascicle. That's a good one. I like that. Okay. I spelled

Isaiah: 39:23

Fascicle. Did I

John: 39:24

must I spelled did I spell No.

Isaiah: 39:26

That's right. That's right. That's right. No. Yeah.

Isaiah: 39:27

That's

John: 39:27

right. You're making

Isaiah: 39:30

did I need to

John: 39:31

put an I in there? I don't know. Alright. It doesn't matter.

Isaiah: 39:34

You really made me was like, wait

John: 39:35

a second. Okay. So, there's no autocorrect for those. Yeah.

Isaiah: 39:40

I wish life had autocorrect, man. That would be nice.

John: 39:42

So, when you when you look at just the muscles ability to apply force, right, during a squat, okay, where do you where can you do the most amount of weight? On the up phase, down phase, or holding it? Where do you lift the most amount of weight? Down phase. On the down phase.

John: 39:56

Yeah. Alright. So, over here, we know that you do the most amount of weight. Yeah. And, what about about concentrically?

John: 40:06

Do you do the most, middle? Least what do you do?

Isaiah: 40:08

Least amount of weight.

John: 40:08

Least. Okay. So, over here, you know, we know can you give me the red? Actually, give me the red and the green. Actually, I'm just gonna draw lines.

John: 40:19

It'll it'll be better.

Isaiah: 40:20

Let's Totally just, like, color blind.

John: 40:22

So we know that do you produce a lot of force fast? Like, if I said lower 500 pounds, are gonna lower it fast or slow? 600 pounds. It would have to be slow. Yeah.

John: 40:30

Or fast. Sorry. It would have to be fast because it'll smash you. It'll force you to go down quickly. Yeah.

John: 40:35

Yeah. Right? So we know you apply, and this is force on this axis. Right? So on the y axis is force.

John: 40:42

You apply a lot of force really fast eccentrically. Okay? In a relatively slow movement. Now, relatively, as you lift less weight, you can control it better. So you can lift it slower.

John: 40:54

Right? So you're less good maximally at producing that. Isometrically, we're holding it. You're somewhere in the middle. Concentrically fast, if I said lift a thousand pounds concentrically on the up phase, right, of a squat, you can't lift that fast.

John: 41:08

Or I said lift your max. What's your max, back squat?

Isaiah: 41:12

Four twenty five.

John: 41:14

Four twenty five deep. Right. You're not gonna lift that fast. It took you like two seconds to do So, you're pretty good at producing force slow. Right?

John: 41:22

Relatively slow, zero degrees per second. And over here, really fast concentrically, jumping, or if I said do a jump squat, you can move one thirty five really fast.

Isaiah: 41:32

Yeah.

John: 41:33

Right? But, it's relatively low force. Right? A 135 is the muscles. It's not a lot of force.

John: 41:38

Yeah. Alright. So, when we look at this, this, my friends, is the force velocity curve. Alright? Shit.

John: 41:49

This is not perfect, but probably be here and then would tail off really quickly there. Alright? So this is, you know, ISO pretty close to the same slow really slow eccentric, really slow concentric and isometric, your force generating capacities are relatively the same. Yeah. As you get to really fast eccentric work, you can lift a lot more weight.

John: 42:09

Like, probably double what you can do isometrically. Yeah. Right? And then if you lift really really fast concentrically, you can't do nearly as much weight. Right?

John: 42:17

You can't lift your a thousand like, could lower 600 pounds fast. Austin does it all the time whenever I put too much weight on his back. He just drops the fucking bar, slams the pins. He's trying to stop it, he can't. And then over here, you know, if I said lift that same 600 pounds upwards, he can't do it.

John: 42:33

Right? He can't lift it fast. But if I said, me take all the plates off and do one thirty five on the up phase, he's gonna lift it really fast. So you would say, well, John, we're supposed to go from high intensity, which is over here, to, you know, relatively lower intensities, which is over here. Right?

John: 42:49

Or maybe like in this area. Okay. Because as you move faster, intensity goes up. So, I would say, yeah. Correct.

John: 42:57

But you're telling me that slow concentric is the most intense specific thing? Correct. So it it it flips everything on its side because traditionally you got the eraser? Yep. Traditionally, I would say, you know what, you need to go from I might have got that on my side.

Isaiah: 43:17

And, he's talking about, remember, when we were looking at the muscular tendon tendinous unit in a stress shortening cycle, the muscle is going under a slow concentric action if you're an elite athlete, which is not what the force velocity curve traditionally

John: 43:33

would tell us. Dude, it's so much better if I can stand in front of it. So, long term, what we want to see is that intensity goes from low over time to high. Okay. We define intensity as the amount of weight we lift at what velocity we lift it, and if it's multi joint movement.

John: 43:52

So jumping is really high intensity, barbell jump squats are really high intensity, low intensity would be lifting a barbell bicep curl slowly at a light weight. It's relatively low intensity. It's single joint, slow, and

Isaiah: 44:04

it's not a lot of weight. Can get, a five pound dumbbell slow.

John: 44:07

Really low intensity. If I said do that same do a row fast, now you're using the biceps still. It's multi joint movement. You're using the shoulder. You're doing everything else, but it's fast with more weight.

John: 44:18

That's gonna be more high intensity. So as we move this way in the force velocity curve, we remember it went kind of this downward slope. The low intensity stuff is gonna be that slow light stuff on the curve. Right? It was kinda like in this area if you could visualize it.

John: 44:32

And then as we get to the higher velocity stuff like jumping or stress shortening cycles where the eccentric force is really high, you know, you would think, oh, well that should be at the end of the progression. Yeah. In a weight room, that's absolutely true. But when you're talking about stress shortening cycles where all of a sudden everything is flipped on its side, in a stress shortening cycle, that is not the case. Okay?

John: 44:51

So in the weight room, I would say, look, we need to focus on concentric stuff early in the year, eccentric stuff late in the year, you know, if this is weight weights. Okay? And then, you know, in the middle of the year, maybe it's ISOs. Now, if I'm looking at a stretch shortening cycle or plyos, and remember, plyos are jumping, sprinting, etcetera, and we draw that same that same thing, low and then we have high over here. Is this still on the you know, I might say

Isaiah: 45:22

Let do this real quick. Just Let me Sorry.

John: 45:26

Don't do that. Whatever. We shouldn't mix these together. Yeah. Alright.

John: 45:38

So now, we're talking about SSC, plyos, etcetera. Now, those muscle contractions, and this would dictate what I do in the weight room, it completely changes. Again, this is complex. I'm sorry. I'm trying to make it simple.

John: 45:51

But these are the implications. So now the low intensity stuff is going to be fast eccentric stuff, because the muscle is you're not storing a lot of like, this is relative to the tendon. You could think of weights as, like, you know, muscle based, but related to the tendon, or you could go slash tendons, right, it completely changes. We should just use one marker from now on. Can you try to get that one to work?

John: 46:22

Yeah. So,

Isaiah: 46:24

this is Oh, it works on this side.

John: 46:26

Oh, what the heck? So now it completely flips whenever we're we flip the script related to this. Can you make this one

Isaiah: 46:32

work? Yeah.

John: 46:34

Eccentric is relatively low intensity because you're not stretching the tendon a lot in a fast movement. Now, isometric, whatever that was was flying. Isometric would be in the middle. And then height would be slow concentric because you're gonna get the most tendon stretching out of that. So that is why this is relevant, is it flips this long term planning on its side.

John: 46:56

If you're looking at the weight room, you can still follow this progression. Right? Just mostly looking at muscle fascicles. It applies. But if you're looking at tendons or faster movements or SSC, it's the reverse.

Isaiah: 47:07

And is this still looking is this a cont the muscle contraction specifically?

John: 47:13

Yeah. This is looking at the muscle contraction. Yeah. Yep. So, This is both talking about training, looking at the muscle because we can't control our tendons lengths.

John: 47:22

It's determined by the activity we're doing thus You're

Isaiah: 47:26

saying you train your tendons by training your muscles.

John: 47:28

You have to. They're connected. So, that said, I mean, again, really complex. I can't really

Isaiah: 47:35

No. Think that was that was really good. If you watched this a few times and It

John: 47:39

should make sense.

Isaiah: 47:40

Pause it where you don't understand it. Replay it. Look up whatever

John: 47:43

And, don't this should be mind blowing to those of you who have extra science degrees.

Isaiah: 47:46

Yeah. Because I know it blew my mind.

John: 47:48

Yeah. Because we were taught the opposite in school. We were taught, you know, plyos or eccentric movements are important because of stress shortening cycle. This kind of flies in the face of all of it, but this is what we're seeing. And we've seen it for years.

John: 48:00

It's just not explained in terms of human performance

Isaiah: 48:03

Yeah.

John: 48:03

In my opinion. So, yeah, that's what I have for you guys. Maybe as we explain this over the years, it'll get easier and I can understand.

Isaiah: 48:10

Definitely won't be the last time we go over this.

John: 48:11

Yeah. But thanks for watching, Make sure you like, comment, and subscribe. Leave us five stars on a streaming platform if you are watching this on a podcast format, and make sure you go to thpstrength.com and sign up for coaching. Use discount code THP at checkout for 10% off your first month.