The Force-Velocity Curve Lie & Why Olympic Weightlifting Is Superior w/ Dan Cleather (SSOF Ep 179)

James de Lacey1:12

So for people listening and they hear that, okay the force-velocity curve doesn't make sense in the real world, how can someone look at exercise then in a, I don't know how to put this, but in a similar framework if that makes sense, where I'm looking at maybe movements that are faster and maybe more speed-based or force-based versus others, since this curve doesn't really fit a lot of that model?

Dan Cleather3:54

I mean there's a very easy way to sort of fix that, and for some people that it will seem like, well okay this is all just semantics. But hopefully I convince you that it's not.

But I guess one way to solve this is instead of labeling the y-axis force, if you just label it load, okay, so how much weight are you carrying, then that relationship will broadly work. The more load you have, yeah, the less fast you can move. So that gives you a handy way to describe this continuum of exercises.

Why I think that that semantic question is important though is that load isn't the same as force. And that's very, very clear when you think about, okay well, sprinting is low load. You're not adding any load, but it's high force. So this intuition that we have that, okay well if we have lots of load that means it's high force and if we don't it's low force, is wrong. We can be very, very low load, but if we're accelerating very hard, it's very high force.

So it's not a semantic question, and if you conflate load with force then you're not understanding what's happening there. So it is very, very important in my mind to decouple the idea of load from force.

James de Lacey5:47

And it originally came from, was it single muscle fiber models around the force-velocity, I guess, relationship and that inverse relationship?

Dan Cleather5:47

Yeah. So that's why people I think looked for this in the first place. And that is that, yeah, there is a relationship between force and velocity of muscle. Okay. So that's a property of muscle.

Because the way muscle produces forces, you've got the cross fibers need to grab onto things and pull. To generate tension takes time. So if you're moving slower, you have more time to generate tension. You have higher force. If something's moving faster, you have less time to generate tension and it's lower force. So in isolated muscle fibers, yeah, there is a force-velocity relationship.

But it's a really, really big leap to go from, okay well in an isolated fiber we have this relationship. Well, that means that the body will show that as well. Especially when lots of the things that we have in our body, the way our body is constructed, is built around trying to manage that property. So for instance, our tendons are very, very effective at mitigating that property of our fibers. The way we coordinate movement also typically helps us mitigate that relationship.

James de Lacey7:24

Awesome. And you touched on, I mean somewhere on that force-velocity curve, typically have power sitting in that middle range and there's all sorts of, we say debate and different thought processes around power development.

You have people who will subscribe to, hey I just trained the velocity end, or if we do an updated version, the load end of the force-velocity spectrum, and those two together come together to create more power. Others will train at optimal power load because that is the load that maximizes power.

So it'd be interesting to get your take on what power actually is and then how, I guess to frame it in a way where, actually if you just define what power is, that's probably going to answer the question itself anyway, because typically most people are just looking at, hey it's force and velocity, but you have an extra definition on that.

Dan Cleather7:24

I mean my answer to the question of, okay well what's the most optimal way to train for power, is, is power what you should be looking at in the first place? And the reason for that is that power in many activities I don't think is the best variable. It will correlate with performance, but it's not going to have the best correlation with performance.

To answer the question, the strict mechanical definition of power is power is the rate of doing work. So then that has to go back further. It's, well what's work? And work is the force that you're expressing as you move through distance. So then it's not very intuitive. Power, you can derive this relationship that power is equal to force times velocity from the definition. So yes, power is force times velocity, but that's not how it's defined.

I guess in terms of, we take as granted that, okay so people hear, okay power is force times velocity, and think, okay well force is good and velocity is good, so that implies that power must be the thing that we're looking for. But it's, well, why?

I think the real reason why people are most interested in power generally is because the word as we use it, people say power and I want a powerful athlete, people think explosive. That means something to us. And we assume that because there's this mechanical variable called power, that that's going to entirely encapsulate the meaning of that word power to us. But I don't think it really is. Power, the mechanical definition of power, isn't really what we think of when we talk about someone being powerful, I don't think.

James de Lacey11:06

So what are we—if we are measuring power, peak power, average power, whatever it is from something—what are we actually seeing under the hood here? Like with the expression of power, how am I... I'm just trying to frame it in a way that makes sense in my head too. Like if we're doing something to develop power, what are we really developing then in a sense?

Dan Cleather11:38

I mean again it kind of comes back to like, okay well first of all what are we trying—why are we interested in power? Like that's a fundamental question. Like what are we trying to improve? What, you know, we're not just trying to improve power because power is good. Like there's something that we have in our mind that we want to improve.

And often in sport like that's going to be some sort of change in velocity. So if you're throwing something, it's going to be the velocity with which that thing leaves your hand. If you're jumping, it's the velocity that you leave the floor. If you're changing direction, it's how you're able to decelerate and then re-accelerate again. So kind of in performance, very often what we're interested in is changing our velocity.

James de Lacey11:50

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You actually answered my dog question perfectly. So the way it was bad, but you answered it perfectly here. So I guess not really a follow-on question, but one that often comes up is the idea of—I guess on this power development or whether you want to do it or whether it's a change in velocity that you're trying to develop—is this idea of jumps versus Olympic weightlifting.

It's a debate that never ends and it'll be interesting to get your take on maybe the key differences between jumping, Olympic weightlifting, and if they are comparable in a way that they can be, I guess you could say, substituted one to one in a general sense.

Dan Cleather14:14

I mean it is a perennial debate, you're right. And the problem, like a lot of debates, is that people take very polarized positions. This is terrible or this is indispensable. And I wouldn't like people to think that I'm taking that position.

But look, Olympic weightlifting does something that you don't get from jumps. And to describe that, again, this comes back to what are you measuring and why? Okay. So if you look—if you're measuring power output—then you'll probably see somewhat similar power outputs between jumps and Olympic weightlifting, which might lead you to the conclusion that they're interchangeable.

If you measure rate of force development—okay, so rate of force development is how quickly you're able to ramp up the amount of force that you're producing. So here I'm not producing any force at all. If I go like, how quickly can I increase the amount of force that's there? For Olympic weightlifting, rate of force development is much, much higher than in loaded jumps.

So kind of, depending on the variable that you're looking at, they may or may not look the same. If you're looking at power output, they might look similar, but if you're looking at rate of force development, they're not the same. Loaded jumps can't replace that.

And that for me is very clearly why Olympic lifts are such a great tool. I mean there are other things where you can have high rate of force development, like true plyometrics. But in terms of activities in the weight room with load, yeah, weightlifting does something that's pretty special.

The question then comes, okay, well what's this thing rate of force development and is it important? And yeah, for me kind of when we're using these terms explosive, the idea of someone being explosive is more described by their rate of force development than it is by their ability to express power. So for me, that's a pretty interesting and important thing.

James de Lacey16:58

Does that change much when you're doing jump versus limit lifts based on the weightlifting variation? I don't know the answer to that.

Dan Cleather16:58

I don't know the answer to that. The interesting thing with weightlifting is the force-time profile. So if you have a graph which is force on the y-axis and time on the x-axis, it's very variable through the movement. And the place where the rate of force development is really, really high is during the second pull.

James de Lacey17:38

So because you get this little dip, right? You get the first pull dip and then kind of come back up.

Dan Cleather17:42

Yeah, exactly that. So it is that second pull movement where the rate of force development is really, really high. And so yeah, in order to get that benefit, you don't need to be doing the full lifts. Like if you're doing hang variations of those lifts, you're in that part of the curve where the rate of force development is very high.

James de Lacey18:14

Got it. I actually have a question in the chat for you from Christian asking, 'What do you think of isometrics for rate of force development, especially the isometric mid-thigh pull compared to the Olympic lifts? Could they replace the Olympic lifts for strikers like boxers and kickboxers, etc.?'

Dan Cleather18:14

I can't think of any literature that I've seen that's compared those things. But I would be surprised if the rate of force development in an isometric pull was as high as it is in a dynamic movement.

I mean for me, one of the things about Olympic weightlifting which is unique—or not unique—but it's the fact that these are ballistic movements. You're throwing something, you're projecting something. And for a striker, when you punch someone you're throwing something at them. Like that thing is your fist. But it's still a ballistic movement. So kind of to me, the regime of work that you're doing is more similar in weightlifting than it is in something that's isometric.

I mean the question for me comes back to, okay, so the question is motivated by, can I replace weightlifting with something? And my question is, well, why do you want to replace weightlifting? You have a tool that works. Why are you trying not to use it? I think the answer that most people would give to that who want to replace it is a belief that weightlifting is hard to learn, or it's the juice isn't worth the squeeze. You don't get as much as you—it's just not worth the time.

And for me again, I don't subscribe to that view. I think that the Olympic lifts can be learned quickly and learning them is an effective way to develop your athleticism. So kind of, I'm not trying to replace them with something else.

James de Lacey20:49

Perfect. I'm going to—I've got some more questions on rate of force—but first I want to come back to something you said. You mentioned about true plyometrics. Do you want to maybe go into detail what you mean by what a true plyometric is versus maybe something that's called a plyometric and maybe not?

Dan Cleather20:49

I mean the often-used definition is just kind of—if you're thinking about jumping exercises—that a plyometric, like, what's the contact time that you have with the floor? And typically people talk about 200 milliseconds. And kind of if the contact time is lower than 200 milliseconds, then it's plyometric. If it's not, it's jumping. And kind of that's a pretty arbitrary threshold.

I think there's several reasons why that short time is important. I mean if the time is short, clearly that's challenging your rate of force development more. You only have a limited amount of time to express force. And there's some reflex-oriented things, I believe—I can't say with certainty—but which, where the rationale for that comes from. But that's not to say that things where the contact times are less than 200 milliseconds aren't good training exercises.

Doing bouncy things, I always see personally a lot of value in them. But yeah, they're not necessarily going to result in such extreme rates of force development as a drop jump where you've got very, very limited time to overcome kind of—

The landing forces and then project yourself into the air again.

James de Lacey23:02

I've always defined it as under 250 millisecond ground contact time. Then you run into the thought processes like okay what if it's 251, what if it's 252, then you go into velocity based training, what if it's 0.81 instead of 0.8 m/s, you know speed strength instead of strength speed or whatever it is and you're sitting there like uh, I guess it's just a general way to categorize, okay it's a fast ground contact plyometric, if you're just jumping onto a box it's a jump and you're getting different things out of them as you mentioned because of that time constraint on them.

Dan Cleather23:38

Yeah. And it's the time constraint that's important, and what the challenge is there. I mean the thing about those true plyometrics though is the way those are often designed is to use your momentum as a tool to allow you to have really really high rates of force development. Whereas if you don't, if you just go and jump as we've seen, you can't get your rate of force development as high as you can in weightlifting.

James de Lacey24:22

A follow on question here from Christian again about what do you think of the current methodologies to measure rate of force development? Are they good enough to compare between exercises? He was saying he mentions there's an article on Sportsmith their rate of force development methodologies are shoddy. I don't, I haven't seen that article. I don't know if you've seen that article or not.

Dan Cleather24:22

I mean the thing with measuring rate of force development, I wouldn't, I don't know about methodologies but it's really really sensitive. Okay. So rate of force, there's various ways that you can calculate rate of force development but really what you're doing is you're saying okay in a certain time period how much did my force increase, okay? And so how big did my force go and what was the length of time and you just divide the force change by the time.

The problem with that is that in particular that's really sensitive to the measurement of the time, especially if you're starting from zero. So if you're starting from zero when do you say that that force started increasing? And if we're talking okay I, if you're interested in the rate of force development over 100 milliseconds say and you're out in when, it's not a trivial problem to say okay when did they actually say go and if you miss it by 5 milliseconds then you get a very different answer.

So the problem with calculating rate of force development is when do you say you started and when did you say you stopped in terms of the timing and the answer you get is very, is going to be really sensitive to that. And that's the problem and it is a real problem because it's very hard to identify when those thresholds are or when those events occurred. And if you have something that's trying to do that automated, so it's a piece of technology that's trying to pick when those events occurred, yeah that might not be very good. That's fundamentally the problem.

So I have a lot of sympathy for that observation. It's not about whether the technology is good enough or not really, it's about how well you can decide okay well when did they actually start expressing force.

James de Lacey27:31

Got it. And more on this rate of force development side, so you have early and late stage rate of force development. There's actually a pretty good graph of Lachlan James posted a while ago just showing the shared variance between rate of force development different time points to peak force during isometric mid thigh pull and essentially how that shared variance drops dramatically as it starts to get into shorter time frames.

It'd be interesting to just hear your take on training. Is there such thing as early versus late stage rate of force development, do you have to do different things to maybe develop these qualities and how much can you improve these qualities just by generally getting stronger?

Dan Cleather28:08

Yeah, there definitely is. I mean you think about it, you've got a force time curve, okay? And the rate of force development is the gradient of the curve wherever you are. So you can take the gradient of the curve early in the middle late and the curve will be changing shape very very clearly. So they're very clearly very different things.

And equally there's different mechanisms which underpin what the shape of the curve is in different places. So yeah, as I remember and understand it, I caveat everything I say, but yeah, the early part of the force time curve is much more neural. So it is about how twitchy you are. Whereas the later part of the curve is more dependent on your strength qualities.

And so if you're looking at someone and you're diagnosing, okay, well here's their curve, where are they good, where are they bad, depending on where you might want to target improvements, yeah that would lead to requiring different methods.

James de Lacey28:08

What could you give some examples and what would be what would be an example of an exercise for early versus late? I'm very general, but anything helps.

Dan Cleather29:47

I mean, I again I struggle with that, but it's thinking about where the target is of the adaptation, you know. So that the target, if it's early, is a neural quality. It's twitchy, so it's activities that are twitchy, right?

Whereas later in the curve, that's more of a strength, I use power, but it's more of an explosive strength quality. So that's more going to be things that are loaded and trying to move them faster or accelerate faster.

James de Lacey30:35

Perfect. So for really general purposes things like fast ground contact like hurdle hops, drop jumps, etc. would be your early rate of force development and then maybe your weightlifting movements would be your late stage rate of force development. Something like that.

Dan Cleather30:35

Yeah, that's how I would see it. I like your schematic there, let's leave it there.

James de Lacey30:35

Perfect. And then I guess we can also touch on, I actually want to go into this, into impulse as well. I'll come back to some other things within weightlifting, but because I think they're probably all tied together anyway. But looking at impulse or thinking about things as impulse, which to me honestly, it helps put things into perspective and helps make things make more sense.

Impulse versus say looking at peak and average force. You know why would someone want to look and think about impulse versus just how much force is created during a movement or how much average force is through a rep?

Dan Cleather31:53

Yeah. So again it comes back to the question of what are we interested in doing? And the thing that we're interested in doing often is changing the velocity of something. Okay. So if we're measuring things, what we're trying to work out is well, what's your ability to change something's velocity, be it an implement or yourself.

The reason why impulse is a really really good variable, if that's what you're interested in, is that because of this thing called the impulse momentum relationship. The amount of impulse that you express is perfectly correlated with the change in velocity of something. So if you're measuring force and you're interested in understanding how velocity has changed that is the variable that determines it. It will be perfectly correlated with it. So that's the reason for looking at it.

So what's impulse? Impulse is force times time, broadly in simple sense, or it's the area underneath the force time curve. So if you're thinking about this force trace that's your impulse. So more area underneath that curve means that you will change the velocity more in that time. So that's the headline figure that equates to the change in velocity.

But also that gives you a basis for then diagnosing why someone's accruing lots of impulse or not. So you look at the shape of the curve and can be well why, how could the shape of this curve be improved. And then if we take rate of force development that we were talking about, well if the gradient is steeper at the start of the curve you'll get more area underneath the curve if it goes straight up than if it's like this.

So thinking about impulse just gives you a lot of mechanical material for understanding movement. If you talk about the other variables that you mentioned like peak force say or power, they do have a good relationship with how much impulse you have. So if your peak force is high then probably all things being equal there'll be more area underneath the curve but it's not a perfect correlation with it.

So looking at peak force will tell you something but it's not the direct variable. It's the same as why you'll still see high correlations between power and jump height or power and change of direction performance because well yeah power is still a measure of how much force you were expressing. So there is a relationship there. It's just not the most direct one.

James de Lacey34:56

Perfect. And I've said this a lot on the channel as well around I think a really easy visualization on impulse is watching an elite Olympic weightlifter jump and then watch someone like a sprinter jump and then you see how low down a weightlifter descends in the jump almost like a full squat to have more time to essentially produce their impulse. Then you watch someone like a twitchy sprinter and they're only doing like a quarter squat. And I think that's an easy visual representation of impulse for someone who's maybe trying to see it in their head if that makes sense.

Dan Cleather34:56

I mean, it's a really good example and it's something that if you're talking about jumping is probably counterintuitive for people. If you want to jump high, that the more impulse you express the higher you jump is perfect correlation. So you want as much area underneath the force time curve as you can.

The question then is, well, if you spend longer jumping, so if you're on the floor for longer, well, that gives you more time to accrue impulse. So, counterintuitively, actually spending more time on the floor means you'll jump higher. There might be reasons why you can't do that. So in some sports you're you know there's a constraint that would make you competitively not as competitive you could be if you spend a long time on the floor but there's other sports where it isn't.

So very much one strategy that you can use if you have the performance qualities to do it is okay well if I have a very large joint excursion then that will give me more time on the floor, more time to express force, and my impulse will be higher. The flip side of that where you're talking about a sprinter is that might be someone who, their rate of force development or the relative qualities they have are that they can accrue impulse quicker because they're a bit more bouncy elastic.

James de Lacey37:22

Yeah and on that idea of impulse as well, so for sports, as you mentioned, many sports are time constrained in movement. I mean you can even talk about the striking example we talked about earlier around throwing strikes. Would you look at skewing a training program then to having most movements in that say shorter time frame? For example, if we just take Olympic weightlifting, instead of going from the floor maybe you're going from high blocks as an example.

Would that be something, would that be a change that would make sense in your philosophy around this in order to be able to generate forces in shorter time frames and almost, I'm not going to say match the impulse to the sport, but you kind of get the idea.

Dan Cleather38:02

Yeah. I mean whenever we're thinking about what makes training specific, you're always starting from a really good point if you're thinking about how force is expressed in the sport itself. The time window that's available for you to express force, that's a key constraint. So having that in your mind I think is always important.

So the answer broadly is yes, in terms of the specifics of the exercise. Doing pulls from higher positions reflects that constraint. However, the exception with weightlifting is well because the rate of force development is so high in the second pull, even if the whole pull takes longer, you're still getting that period where the rate of force is high even if you go from the floor.

So in this case it's probably fine and the more of the question is okay if you go from the floor does that change what the rate of force development is in the second pull and some people would argue that yes that is the case.

James de Lacey38:21

That was a good answer, I like that. And you mentioned specificity as well, I'm going to come back to that but I actually want to just quickly jump on because we're talking about weightlifting around triple extension, because it's something that's often emphasized heavily even within Olympic weightlifting coaching and obviously within all sports. Everyone's talking about triple extension with running and all sorts of things. So, be interesting to hear your take on the importance or unimportance of emphasizing triple extension in training and what it really represents, because I remember you talked about within your force book too.

Dan Cleather40:03

Yeah. I mean it's another thing where I think there's some misunderstanding. I mean clearly when we're exerting force against the floor we use our ankles and the knees and our hips. Okay. So we do triple extend, not arguing for one second that that's not important.

Where I see problems in coaching of things like jumping, sprinting, punching as well I would imagine, or weightlifting, is that people emphasize the end of the extension. So triple extension is really important. So like I'm going to really emphasize to someone that they really hit that end position. And the problem with that is that you're then, if you take the example of jumping and you're emphasizing, okay, that extended position just before you leave the floor, you're emphasizing a position where they're not actually generating force anymore.

The point just before they leave the floor is not where the work is done. The work has already been done. So if you bring someone's attention to there, you're actually asking them to do something in a region of the movement which isn't that important. And that actually, although you do see someone hit this full extended position, they do that because of things they did earlier.

So that doesn't mean that a coaching cue which says get fully extended is bad per se. It could be a good cue if what it does is make them do what they needed to do earlier to get there. But in practice, I think often that's not what happens. In practice, what happens is it makes people spend too much time in the place they don't want to be, trying to get under the bar or anything like that.

If you take sprinting, if you really emphasize someone to push off, they'll leave their leg behind them inappropriately. That's not, it's a bad cue. It's the same as punching. With punching you don't put the emphasis on, the power doesn't come at the point where you're making contact. You've thrown this thing with your hips at the start of a movement.

You do need to, there's difference there because you do need to stiffen at the end so that you transmit that momentum to the other person. But you don't hit someone hard by emphasizing get there. You hit someone hard by emphasizing what's happening here.

James de Lacey42:14

No perfect and then I want to come back to the specificity side as well and obviously I'm sure you're on social media and see all sorts of what we call quote unquote specific exercise going on. So, let's just go straight into what specificity actually is and how can an exercise be categorized specific to a certain movement? Is there even such thing? Because obviously there's a big push back on specificity too where a lot of people are saying, "Hey, training is only GPP. There is there are no sport specific exercises." So, it be interesting to hear your take on all of that.

Dan Cleather43:42

Yeah. My take on it is that well, if you're doing something that isn't your sport, with the aim of being better at your sport, you should be very interested in whether what you're doing is actually going to translate into improvements in your sports performance. So the motivation is sound. Okay. The question comes then of okay well yeah, we want to make sure we have transfer of training so that whatever we were doing outside of our sport does transfer into our sport. And then, how can we make sure that that happens.

The weird and wonderful exercises that you sometimes see, are motivated by the thinking of, well, what's going to make this more likely to transfer to my sport is if it still looks like my sport. And that's understandable, but the reason that you've moved outside of your sport is already because you've recognized that doing your sport isn't producing the returns that you want anymore. You've already come to something where you've kind of come to some conclusion of I need to do something a bit different.

So then for me, well coming to that conclusion that but then just trying to do the same thing isn't the most productive place. If you've made the decision that okay I need to build some qualities that are fundamental to my sport which I can't build within my sport itself, that you want to choose the tools which are most effective for that.

So then that comes to this argument of well GPP type exercises. GPP exercises are typically very good, very helpful at building raw capacities. What you need to think about is are these raw capacities that I'm building ones that I need in my sport, because if not then they're not going to transfer. So that's where the things that we were talking about before of okay well what the time constraints available to express force here, how is force expressed, what joint ranges is most force expressed in. Thinking in terms of these terms, those are the more specific questions. It's not about sport, it's

Does the way that I'm expressing force in similar to my sport? So then if you're looking for the transfer of training effects, pick something that's good for developing a raw capacity and that's most effective for developing that raw capacity that I need in my sport. Once I've developed that, then let's think about, okay, well, are there some exercises that I can do that help me sharpen the edge of that capacity, make that capacity more available to me?

The problem with the weird and wonderful exercises often is that although they're clearly engaging motor patterns that are similar to the sport, they're not very good for actually building capacities. Generally in training we have this—I mean you use the term GPP—we have this GPP, SPP, GPP, SPP, preparation, sharpening, accumulation, intensification. We have this model in training, bulking and then cutting, whatever it is. We have this very well-established methodology across training practices which is build, sharpen, build, sharpen, build, sharpen.

And that's once you start stepping outside of your sport, I think that's the mindset that you want to be in. It's okay, build something general that's relevant. Make it more specific. Build something sharp.

James de Lacey48:27

Do you have very maybe pick any random sport that that works, but what would be some examples of something that would be kind of general there and then how would that change to be I guess quote unquote more specific in that realm? Could we even just say say general would be a full squat and then a specific would be like quarter squat for I don't know sprinter or something like that? Would that be close enough or would that still be too both too general?

Dan Cleather48:59

I mean take punching, okay? We know that the effectiveness of your punch comes from the ground. It comes from your legs. So the raw capacity then is well, what's my ability to put force into the ground?

So at the most general level, full squatting is a fantastic exercise for building leg strength. But also some core strength which is going to be relevant to punching as well. But clearly being, you know having a big squat doesn't mean that you're going to be a big puncher.

So once you've built a bit, once you've got some more strength in your legs generally, you then need to make sure that okay, well, that's probably through a wide range of motion, but when you're punching, it's a less large range of motion. So yeah, maybe doing something that's a more abbreviated range is relevant.

But then also making sure that you have the capacities to be able to couple that pushing in a very axial sense. Making sure that you can convert that axial force into some sort of rotational force, or that this very linear up and down movement is able to be—you go from okay well first of all let's just get strong legs but strong legs doesn't mean big punch.

You then have to think about okay now well now I've got my legs a bit stronger. Let's make sure that I know how to use that, and that's the range of activities of teaching the body, okay, well, you've got this new capacity, here's how you integrate it into the skill.

I mean in some cases it maybe doesn't have to be that kind of pedagogical a process. If you are choosing exercises that really improve the capacities that underpin the sport, maybe when those capacities go up the athlete can just naturally tap them. Maybe they can't. Maybe there's a weak link in the chain which is okay they've got stronger legs but they don't have the core strength yet to be able to convert that into a punch.

So I think that's coaching. One is okay well understanding what are the raw capacities that are important and the tools—there's some very effective tried and tested tools where you can build those. Then the coaching aspect of it is looking at your athlete and thinking about okay well are they really using what they've built and if they're not, how can I solve that problem to help them learn how to use that in the sporting environment.

James de Lacey52:27

Perfect. I want to get to this question before we run out of time and maybe get to another one after that. This one I actually had Perplexity help me go through some of your old podcast. Perplexity is awesome. And this one came up and I was like, oh, this would be this would be nice. This tickles my fancy too around this idea of biarticular muscles creating internal and external rotation and not just flexion and extension.

So we just need to maybe go through that explain that what that means for everyone who's listening and then what does that have implications in our training and if so why or why not?

Dan Cleather52:27

Wow. Yeah, that that's a that's a tough one to do.

James de Lacey53:09

You can blame Perplexity, not me.

Dan Cleather53:09

I don't know what it is but I already hate it. I mean biarticular muscle function is a—the why we have these biarticular muscles in the first place isn't completely obvious and clear. There's some explanations that people offer that I think clearly provide some sort of partial answer to that, but yeah they they have a very, they have lots of effects.

And we're very very accustomed to thinking about our movement in the sagittal plane. So if you're looking at someone from the side, you're looking at someone at the side when they're squatting, thinking about okay, well, what what's happening here, and we tend to neglect what's happening in the other ranges, in the other planes.

So if you have a biarticular muscle, clearly when that activates—if I had this—it creates a rotation of the bone in the sagittal plane but it also creates rotations of the bones in the other planes and I think those are things that are interesting to think about as well.

James de Lacey54:52

I'm sorry I threw a curveball at you with that when I saw that one. I was like, oh, that would be a cool one. Even for me around the biarticular stuff around hamstring training stuff that I implemented a lot was rotational-based hamstring movement because rotation is one of the I guess movements hamstrings help perform of the lower leg. So I was like, okay, so I'm not just going to do your typical flexion extension or or whatever it is from the hip or knee.

I'm going to involve some kind of rotational aspect to it. And to me, it makes sense in that aspect in terms of the implication at least in training. But yeah, it was just an interesting question that I thought I'd throw at you to see if there was a—

Dan Cleather55:33

I mean I think, I mean if you're thinking about biarticular muscles—what's more, if we if we're back in the sagittal plane and we're thinking about it, it's pretty hard to work out, or or or it it's non-intuitive how those things work. So I think even though we know that it's, if you take the hamstrings okay it crosses two joints, we still tend to think of it as if it was a monoarticular muscle. So okay, it's going to flex the knee and extend the hip, but it's not attached to your femur.

So yeah, it will pull up your calf and extend your torso, but it's also going to do something to your femur itself. Your femur is not just passive. Your femur is rotating as well, but your femur is rotated by the forces that that muscle create at the two joints. So when your hamstrings go on it's not just that your calf will move, it's also that it it will tend to rotate that bone because of the joint reaction forces that it's creating. So it's actually a pretty funky thing.

James de Lacey57:08

And I can imagine that it probably has implications in hamstring injuries and all sorts too, with maybe certain parts of the hamstring becoming more stretched during the rotation with different movements and things like that. Yeah, it's a cool topic. I like that one.

And just to round this off because we don't have much time. Force absorption, probably a topic you have been asked about multiple times and one that still permeates all the internet. What is it? Does it exist or not? And should people even worry about it?

Dan Cleather57:43

Yeah. You can't absorb force. That's something that we talk about a lot in strength and conditioning. We kind of know what we're talking about, but force isn't absorbed. You don't have a sponge that sucks up force, so that terminology is just incorrect.

And if you think about it, if you think about someone who's landing from a jump, well, you don't get rid of force to land softly. You create force to land softly. So again, it's something that we kind of know what we're talking about, but it doesn't make sense mechanically.

What you're doing when you're absorbing force, say if you're landing from a jump, you're landing softly, you're bending your knees more and cushioning the landing. What you're doing there is you're just reducing the peak forces that are experienced. So again this is an impulse question.

So if you're landing from a given height you have to change your velocity. In this case you're going from a landing, whatever your landing velocity is, to zero. Okay. So there's a fixed amount of impulse that you have to express to do that. If you do that in a short time period then because impulse is force times time it means that your peak force has to be very high or the forces have to be very high and that has a greater risk of injury.

Clearly if you are able to land over a longer period of time then the forces that you need to express don't need to be as high. So you reduce your injury risk. So that's kind of what people are seeing when they're saying force absorption. They're seeing that there's not as much force, there's not as much peak forces in those landings and they like that, but there's no force being absorbed anywhere.

You're just choosing a strategy which means that you spend a little bit longer landing and means that the forces don't have to be as high in it. So those landing strategies are force mitigation things. There's no possibility to absorb force.

James de Lacey57:43

Do we have one more question in the live chat for you? I'm going to throw it to you quickly. What do you think of eccentric overload training for improving peak force and rate of force development?

Dan Cleather1:00:28

I mean for me that would be okay. So you're training in an eccentric regime.

James de Lacey1:00:38

Yeah. We'll just say a typical, I know 105 110% 1RM lowering down kind of thing.

Dan Cleather1:00:47

Yeah. So again, it goes back to thinking about how force is being expressed and in the training activity or in the sporting environment. Choosing an activity that allows you to overload the amount of force you're expressing is an interesting stimulus for your body to increase its potential to exert force.

If it's eccentric though, you're expressing that in an eccentric regime and if what you're interested in is your ability to express force in the concentric regime then that's somewhere where the two things don't line up perfectly. That doesn't mean it has no value, it's just understanding where the trade-off is.

So here your trade-off is okay I'm interested in having a higher force in the training activity. See, because that's an interesting stimulus, but then you're having a contraction type that might not be as relevant. If the contraction type that's relevant to you is eccentric, then great. It's a more specific exercise.

So again, I don't have any strong feelings about is it good, is it bad. The question is how is force expressed here and how do you want force to be expressed in the sporting environment?

James de Lacey1:02:27

Perfect. Perfect. Dan, plug your books and where people can find you.

Dan Cleather1:02:33

Thank you. Thank you for the invitation. Yeah, so the best place to find me is my website. So that's dancleather.com. And you can find my books on there. A lot of what we've been talking about is biomechanics. So kind of the best starting point for my biomechanics writing is a book called Force, the biomechanics of training.

James de Lacey1:02:58

A good book, by the way.

Dan Cleather1:02:59

Thank you. And then my most recent book is called The Practice of Change, the art and science of training. So that's more philosophical. It's about the training process. But yeah, and then there's a couple of other books there, another one about training, some more about biomechanics. You can have a poke about on my website if it's interesting.

James de Lacey1:02:59

Perfect. I'll link all that up for you and for anyone who's listening, I'll put that all in the description so you can check it out as well. But I appreciate you coming on, Dan. I'm glad we got this going.

Dan Cleather1:03:34

Yeah. Thank you so much for having me. It was great.