Using Force-Velocity Profiling For Maximizing Power Development w/ JB Morin (SSOF Ep 90)

JB Morin1:19

And because this relationship is sometimes different between different individuals, I don't have the same force velocity relationship, for example in squatting, than you have, we call that a profile to put the individual differences behind a general relationship. And there's quite a debate on the shape, the overall shape of that relationship. But I think there is very little debate in facts, because the shape is different and it doesn't mean the concept is flawed. It just means that the shape is different depending on the thing that we are measuring.

So that's the overall idea, is that it's exactly the same as the load velocity relationship, except that you plot the load against the velocity you were able to move it, instead of the force output you were able to generate. So that's that's the tiny difference between the two.

James de Lacey3:23

Gotcha. Yeah, and we'll dive into some of that, I guess we could say controversy, because there are definitely some people out there trying to discredit a lot of the, I probably say the work you've done in terms of this force velocity profiling. But before we get there, let's see if we can take this down the rabbit hole and get it practical for the listeners as well.

So the force velocity profile we talked about how it's an individual profile for the athlete. So firstly, how do you determine a force velocity profile for an athlete? And then once you've done that, what does that mean? What can I do with that data?

JB Morin3:54

Yeah, so it all depends on the movement you want to assess. Because my profile in cycling will be different from my profile in squatting and from my profile in bench pressing and so on. So I think it has been studied for something like 20, 25 different types of exercises. We've had students here doing a landmine push type of profiling.

But let's say that we take a very simple one, squat, squat exercise. You will need to measure both the force outputs, so my pushing force during the squat, and my velocity of movement, so my velocity of leg extension during the squat under different loads. Because if you want to have different points in that profile, you will need to have some points in, let's say, the high force/low velocity end of that spectrum, and some points in the middle of that spectrum, and some points in the high velocity, low force end of that spectrum.

So let's say that if you ask me to do something like four to six different squats with different loads, ranging from my own body weight to let's say my body weight plus my body weight, let's say that you will end up with some force outputs and some velocity output, and you will be able to draw my force velocity relationship. And this happens in cycling, it's been published like 30, 40 years ago, squatting, bench press, all types of rowing, horizontal press type of push, sprinting of course, and so on. So that's the overall idea.

And then it will give you three main informations. First, the maximum force outputs that's possible for that system in that specific exercise. Very often we call that F Max or F0 because it's the final end of the spectrum. Conceptually, it's very close to the 1RM load or to the 1RM force that you're able to use.

On the other side of the spectrum, it's going to give you the maximum velocity side of the spectrum. And if you mix both, you have an idea of the maximum power output. So I know that very strictly speaking in biomechanics, we shouldn't call power something that has a dimension of a force multiplied by a velocity, because they are scalar vectors and so on, vectorial entities and so on.

But I like the idea to say that if we want to mix these two mechanical entities, we can have an idea of the quasi power. And I think if people are happy with quasi power, then let's go with quasi power.

The idea is to say, when we mix both the force output and the velocity of movement, we are assessing something that is mechanically there. It's the ability to increase the level of mechanical energy of our system over time. And that's work over time. And mechanically, work over time has the dimension of power. So it's the work associated to that force we are pushing.

James de Lacey7:04

Nice. With the profile itself, so just I've just, running down a couple of questions here to follow on there for the listeners to help them along this as well. So you're talking about doing squats there, getting the force velocity profile. Do you find there is a preference towards whether you're doing something like a back squat to create the profile versus maybe a jump, like a loaded squat jump?

JB Morin7:37

Well, it's exactly the same. Well, it's exactly, if you start from the same position, in the same angles and so on, and you, it's exactly the same exercise. It's just that squat only. So very, very importantly, for every rep you need to produce your maximum intensity. So the maximum velocity of movement. That's by default, but I should emphasize that it's always your maximum intensity.

So it means that if the load is too light and if you produce your maximum intensity, then it's going to be a jump. Then it's going to be a squat jump. At a certain point, on average, our own observation is that around body weight for most non-specifically trained people, you will push that load very fast, but you will not take off because you don't have the physical ability to take off. That's going to be a squat or a half squat.

So it is not, there is not a half squat profile and a squat jump profile. It's all the same movement, except that the load will tell you if it's going to be a jump or if it's only going to be a push, you see?

James de Lacey8:37

Gotcha. Now that makes sense. I'll jump into some of the protocol stuff in a second. But with that squat profile, you have that linear force velocity relationship, but you also have, at least within the app and in the old spreadsheets, it was an optimal profile. Maybe dive into a little bit of that and kind of what that means practically.

JB Morin9:03

Just before that, and we need to be very, very clear with the fact that when you assess two players or two athletes, they may have some parts of the profile that are similar, but some other parts of the profile that are totally different. And this is very important. Not everything is parallel.

And just because you have a maximum force in your profile compared to my profile doesn't mean your entire profile will be parallel and above mine. And we have some very, very big surprises. For example, on a rugby team, you have some...

Very mixed observations, and this is why I think it's interesting to have the entire spectrum rather than just one measurement under one single load. If you and I do a squat jump and we produce the same force and the same velocity, it absolutely doesn't mean that our entire spectrum is the same because I can anticipate that your force side will be higher than mine and vice versa.

Now in terms of optimal, this leads to the question of the optimal profile that Pier Samozino has formalized and shown mathematically and experimentally. The idea is very simple: you can have the same maximum power outputs with very different combinations of force and velocity in terms of maximum values. So based on that, this is what we observe, for example in cycling. You can have the same maximum power output in cycling and very different maximum force and velocity ranges.

The question of the coaches was: who jumps higher in terms of body weight classical squat jump height? To answer that question, it was very difficult experimentally, so Pier Samozino has formalized the model that has been clearly detailed in several publications and that has been also confirmed by experimental data. The model shows that the jump height is explained around 70% by maximum power output or the maximum impulse you can produce, but for the remaining 30% it's explained by the orientation of your force-velocity profile.

Due to that, we were able to compute an optimal value for that profile that would maximize your jump performance for the same given level of power. So it means that if you and I – and we have now plenty of experimental data showing that – if you and I have the same power output, the same push-off distance, our performance at the squat jump might be different because of the orientation of our profile. If we have exactly the same profile, then yes, our jump will be the same.

I have formalized that in a Sports Medicine commentary paper to say jump height is a very rough indicator of power output when you measure everything with a force plate. So there's no field method debate. You don't have a perfect correlation between jump height and the maximum power output for the reason of the profile and the optimum profile.

James de Lacey12:13

Nice. With the optimum profile in relation to the individual profile, I think it would be nice just practically what that means for training. So take for example, let's just say my profile is slanted more towards the velocity side. I have a lower force end and then my optimal is maybe more force-orientated, more vertical. Do maybe just dive into how that then influences training.

JB Morin12:47

As I said before, it's not the only key to jump height, and this is a very important misunderstanding of our research. People jumped on that thing and saying that we think that everything is related to the optimal profile. No. In some of my advices I give to athletes, for example in young tennis players, they want to improve their mechanical power output. I never tackled things around the profile. I just use a very general power training because that's where you have most improvements.

But when we assess the jump height and we compared statistically the explained variance in jump height from maximum power output, there was about 30% of that variance unexplained that remained explained by the relationship between the actual profile of the player and the optimal profile. So the advice is very simple: you have two ways to improve jump height. One is to improve maximum power output, and the other one that's also there is to get that individual profile closer to the optimum.

And this is why sometimes I see some very crazy type of criticism saying this is rubbish and don't care about that, it's too complex, just work on power, anything that will develop power will be useful. I say yes, this is true, but with some athletes, at some point developing power is not possible further and then you need to consider that. We've seen some improvements in jump height in professional rugby players after years and years and years of training for the power output without considering the orientation of their force-velocity profile. We had that next step of improvements thanks to that profile.

So it's not either/or, it's take both. Maybe if the low-hanging fruit is improve your maximum power, then yes, don't focus on the individual profile.

James de Lacey14:58

I think as well it can be an indicator, right? So for example, that rugby player, maybe a lot of their maximal power work is geared more towards say the force. Maybe it's like power cleans, loaded jumps and things, but their profile is already kind of force dominant. That profile kind of gives you an indicator that, hey, maybe he needs more on the speed side to orientate that to improve power.

JB Morin15:26

Yeah, and the first question – same thing, same misunderstanding with our research – we are not telling everybody to do that. The first question is the context question: do you need to improve your jump height capability? The answer is no, then don't care about that, do something else. The answer is yes, then okay, you can consider that.

So if a front-row rugby player needs more force output to push at the scrum and everything and doesn't give a damn about jumping higher, then you don't consider the method and the approaches we provide.

James de Lacey15:58

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Gotcha. So in I guess in the context of combat sports, we have say grapplers that are more on the force end of the spectrum, strikers more on the velocity of the spectrum, you got MMA kind of in the middle as a hybrid of both. You mentioned there obviously around front row forwards, okay, they just need to put more force to push harder. Do they need to worry about the profile, maybe not.

I think obviously there's quite a few papers showing different sports have different I guess general profiles about them based on what they are. So is there an application within sports, say like combat sports, where there is no jumping but there is obviously an importance of producing power? So is optimizing that profile important, or is it just, hey, you just got to try to have both ends of the spectrum regardless anyway?

JB Morin18:13

Yeah, that's close to be the same answer because definitely that concept is around jumping, so it's around ballistic, let's say ballistic lower limb push-off that is mostly jumping vertically speaking. So again, it's the same for weightlifting. We have a lot of weightlifting research and things going on like is there a link? But first and foremost, this concept applies to jumping capability.

So I wouldn't be surprised if there's no clear relationship between the striking power or the striking speed and the lower limb profile. That would be totally disconnected to me, but it could be. It's a very simple test to run, and it could be a way to better understand the overall physical capabilities of the athletes. But there are some sports where it's not a big key.

So it's, to me, it's a three-step line of thinking. First, what does the athlete need for their performance? Second, what do the athletes have in their system? What is their profile? And then do we want to improve, change it? If the answer is no, they don't need to jump, then maybe we don't care about that.

James de Lacey19:12

Gotcha. Interesting that you mentioned about the jumping and punching. So typically you have the legs as one of the key contributors for punching power, and jumping is obviously seen as one of those things to do. But I think Andrew Usher, he's publishing some research – I don't know if he's publishing some research on it, but he has some data on it – where I think he's one of the only people that's come out saying that jumping does not correlate well with punching power, at least within his data set. So it's an interesting concept. Maybe it's a research thing, I'm going to...

JB Morin20:11

Absolutely. And I have the same discussion with golf physical prep, telling me that he has observed over the years that there was a very good correlation between the squat jump height, so the lower limb capability to jump, the golf players, and their drive, their length of their drive capability. And so based on that correlation, that could be interesting. But again, correlation is not causation, so we need to focus on, okay, if I improve this, will the other one, the other variable, improve as well?

But again, there are some situations, some sports where it doesn't make sense to correlate with. We don't want to push everybody to assess that. We just want to say if you want and you need to assess that, then that's the way to go.

James de Lacey20:42

Gotcha. And you mentioned these other exercises that you've been looking at, things like the landmine, the landmine press, bench press, and things like that. How would that then relate to physical preparation, say within combat sports as an example?

JB Morin21:11

Yeah, so that was something developed by one of my master students there. He developed the reliability of a landmine throw test actually, and he was able to calculate the force outputs in the direction of motion and the velocity of the load, basically, and of the arm push, and see that that was clearly linear and that was reliable. So then it could have an idea of the overall force capability in that, in that very specific type of motion.

It was very close to... It was the closest you could find, much better than the bench press that is absolutely not close. It was a way to be closer to that punch movement. And then the idea is to say, okay, I want to better identify my athletes. I mean, that's the overall goal of all the methods we propose: it's to go one step further in identifying the force output of the athletes instead of using throwing a ball type of test or just the jump height.

We know that jump height is a very good indicator of jump height. It is not a very good indicator of the muscle and the neuromuscular system capabilities.

James de Lacey22:14

Now that makes sense. So let's just theoretically this punch throw test you've done a little profile, you get your little force-velocity relationship, how is that then influencing, or is it influencing at all, much of the training program?

JB Morin22:14

I don't know because that's not the step that we have studied so far, but that's a step that that student or the physical coaches can use. Because the overall idea, again, is to improve either punch velocity if you see if that is something to be improved, or the overall punch power, because you can be very fast but your action doesn't deliver as much power as you would like to.

So I think that's a good way to say, okay, again, the assessment is going to link the objective with the training content. Because if the objective is to bring more power and the assessment shows that there is a lot of velocity, but that other component that is missing is maximum force output, then you can orient things a bit, I think a bit better, than doing an overall general type of training.

Because the overall general type of training will be efficient for everybody at the beginning, but then you need to dig deeper and... It's exactly the same story as you want to improve in your 10K running performance.

You never trained, do some 10Ks, you will improve almost every time. But then you will have to dig deeper into what is my limiting factor, because I see that my 10K performance is plateauing by repeating 10Ks. So general training, I think, works at some point, but then you need to detail a bit more what's there.

James de Lacey24:17

Perfect. What's the actual protocol itself? So let's just take the squat profile in itself. So something that I've used a lot, I don't know if it was our mutual friend, colleague, Matt Briscal, and yourself that put this forward, that I use with team sports, obviously, because doing it by percentage of body weight is a mission if you've got 30 people, right? So it would be a squat or jump with no load, 20 kilos, 40 kilos, 60 kilos, and that was it. Is that something that you would still use, or you doing something a little different now?

JB Morin24:17

Yeah, absolutely, it's my go-to. So the idea is that you need to have... In my opinion, there has been some publication showing that you can have the entire profile that's linear for the almost the entire spectrum, but that's, let's say, quasi-linear so that everybody's happy. Nothing is never perfectly linear, except a two-point relationship. But you can have that with only two points: a very light load, that's going to be body mass, and a very heavy load, that's going to be, let's say, body mass plus 75 to 100% of body mass.

But I think if you can spend a bit more time, four points is a bit better for reliability, especially in people who are not perfectly reliable and used to testing. There has been some studies showing the relationship is unreliable when the people are unreliable in doing a loaded squat. I did that even yesterday with my master students. Half of the group had some very linear perfect relationships; the other half, the R-squares were totally wrong, not because the concept is flawed, because they were not used to testing.

So yeah, I found that 0, 20, 40, 60 kilos is very good because, first, it's absolute loads. It means you can test many athletes around. We don't need relative loads because all we are looking for, everything we are looking for, is four points down that spectrum, but it's the same spectrum. So if we spend a lot of time calculating, setting every player's load perfectly, we are losing time.

The only modulation I can find is that if that 60 kilos... First, we never go below 20 kilos. So for very light athletes, young athletes, that might be a bit heavy at some point, but again, if you want to profile the players, they need to be ready to. So doing 2, 4, 6, 8 kilos doesn't make sense. You will end up with some things that are too variable.

And then if that 60 kilo load is a bit too light for that big monster, 100 kilos body weight and so on, then we push that to 80. Sometimes with Matt, at the time we tested some guys with their own body weight, 100 kilos, it's a bit too much. You don't need that. But 80 is a good in-between. And for lighter people, sometimes women and so on, if 60 is too much and there is no clear jump, it's like a squat push, then we go to 40 and we modulate to have 0, 20, 30, 40, or something like that. We need to adapt the load.

But remember, remember that lightest load is zero body... That's body mass. And the heaviest is very often around 75% of people's body mass, roughly.

James de Lacey27:15

Yeah, I remember when we did the initial testing many years ago and we were having the players jump with body weight on their back, and man, that was scary.

JB Morin27:15

Yeah, we did it in pro rugby here as well, and it's scary and it's not necessary. Because if you have a very good relationship that's reliable and the highest load is 80 kilos and the guy is a monster and he jumps 30 cm with 80 kilos, then that's fine. You don't need to have that extra load heavier.

James de Lacey27:43

I remember at some point it was the last jump should be below 12 or 10 cm. Is that not a... Don't need to worry about that?

JB Morin28:10

Yeah, yeah, that's something like a threshold, because below that, so 10 cm is... If you jump less than that, it means that very likely either the load is too high for you or you're not used enough to jumping with that amount of load, and there's a big risk that you're not actually jumping. So it means that your center of mass doesn't go... You're flexing the knees very quickly and get your feet back on the ground, and artificially, if you measure jump height with the flight time method, it's an artificial jump height.

If you look at the impulse, there is nothing. So this is why for people who are measuring things with a force plate and the impulse, there's no problem here. But for people who are estimating jump height based on the laws of motion and flight time, then yes, you need to have a load that allows you to jump at least 12, 15 cm.

James de Lacey29:05

If someone wants to start measuring this themselves, what are the easiest ways to do it? I'm assuming just the My Jump 2 app on the phone is probably the easiest.

JB Morin29:05

Yeah, sure, easiest slash cheapest. Because at the end of the day, this is... So why some people are mixing very often the methods with the concept, and when they see that a simple field method like the Opto Jump or the My Jump app gives some unreliable results because of the unreliable testing, they conclude that the entire concept is flawed, then you shouldn't use that, which is an intellectual misconception, clearly. You've seen that.

So if you have money, then buy a force plate, jump on the force plate, use it to determine jump height based on the impulse-momentum relationship. That's gold, perfect. If you have less money, you can use the Opto Jump system, but it's...

Still very expensive. And if you have even less money, you can determine jump height based on the flight time. This has been done, it's based on Newton's laws of motion applied to the center of mass. It's been done for the first time in 1974 in the research, and it's now integrated in that wonderful app, My Jump app.

And I think there has been more than 10 or 50 validation studies comparing the app jump height to the force plate jump height. They all conclude the same. There has been some meta-analysis published showing the same. So now it's okay, we don't need more validation, it works. But be careful: as any device, you can have some very unreliable data by using it in an unreliable way. You give me any device here at the lab, I can have some very wrong outputs easily.

James de Lacey30:34

And that's based on the frame rate you film at, the frame rate you input, everything of the phone, everything.

JB Morin31:04

If your athlete takes off with the foot like this and then in the air brings the foot to land with a flat foot, you have 5 centimeters wrong estimation. That's it. If the day after it doesn't do that, then you have an inter-day difference of 5 centimeters. Will you conclude that the method is wrong? No. You will just conclude that the test was done in an incorrect way.

James de Lacey31:04

I've had plenty of weird results before. And I know something's gone wrong or something's gone down. That's the easiest thing to do: a wrong test.

It's tricky though, because even for me, if I do a force-velocity profile now, it's always from a squat jump, so pausing from the measurement, made on a box or with the thing on the right. Because the countermovement jump, I cannot get that right ever. Just putting a band at the height to touch and go, it's so variable in the depth that I just can't get the consistency. I don't know if you—

JB Morin32:00

To be honest, there has been some studies showing that the CMJ profile was not reliable with some athletes who are not reliable in that CMJ depth. What we've observed is that when people are used to do it and they are physically skilled enough to be reliable, we observe that when the CMJ depth is reliable, then the push-off distance is reliable by definition, and the measurement is super reliable.

So that's again—I am not very powerful and I'm not very skilled at jumping, but believe me, if I do 10 reps, I will do 10 reps with less than 1% difference. So that that's also part of the test.

James de Lacey32:31

I'm pro in reliability, not in performance.

JB Morin32:31

Perfect. But it's exactly like a basic running test. I usually, when we have debates around the FV profile, I take people to the physiological test. Take a Bronco test or take a very simple Cooper 12-minute test. You can be very, very, very variable in that just because you don't know how to pace yourself. Then you can become very, very reliable after knowing how to better pace. So you will never conclude that you should not do the Bronco because it's too variable. You will conclude you should get familiar with the Bronco so that it becomes reliable.

James de Lacey33:01

Because I've had people go out too fast on certain tests and they gut out.

JB Morin33:01

Of course, especially young people or untrained.

James de Lacey33:32

No, exactly. So just to bring this back to combat sports: we probably somewhat answered this, but just to cement it for the listeners as well. Just the force—some kind of force-velocity profiling for improving maximal power development—is there any real use within sports that don't involve jumping or sprinting?

JB Morin33:32

Honestly, I would tend to say yes and no. Because no—basically it's, it doesn't make sense. Okay? Because jumping, if jumping is not one of the key performance components, then there's no point in improving jumping.

But there might be some indirect types of transfer that we don't know, because we don't know everything. I give you an example: I've been in touch with a pro cycling team, and they wanted to improve their sprint power, their sprint performance for their road cyclists. And one of the physical coaches said, "Okay, we usually do strength training and we usually program the strength training without too much thinking. I'm just going to try and have the guys orient their training according to their jump profile, just to have something more different."

And he observed that by doing so, the guys improved their cycling sprint power. So it means that sometimes, just by better identifying the mechanical capabilities of the system, regardless of the future application, you can have some things that are interesting.

But again, there are some sports in which I would tend to say to people, "Yes, forget about that. It's not important." I give you the example of tennis. I work a lot with tennis now. Measuring the entire sprint profile for tennis players is almost useless because everything that occurs after 3 seconds of all-out push is absolutely irrelevant. So I have no reason to say, "Okay, we want to push the maximum velocity of that player," because that's not the objective.

So we need to go through a deep analysis of the performance itself first to then answer that question. But again, we don't push everybody to measure and improve their profile, of course.

James de Lacey35:20

Gotcha. Actually on the sprint—this is away from combat sports now—but on the idea of sprint profile. So when I was doing sprint or horizontal force-velocity profiles to some of my players at one point, the only way you could, I could really, I guess, influence programming was taking almost like a z-score and then grouping them based on the group average on—I think it was on ratio of force in that instance.

How are you doing some kind of individual or influencing programming from that sprint force-velocity profile?

JB Morin36:22

So in sprinting, it's a bit different because the concept and the mathematics and the modeling behind is a bit different. Overall, Pierre Samozino has shown that yes, there is about the same concept: that for the same maximum power output, the performance will be different with different slopes. Yeah, this is the theoretical part of things and the mathematical part of things, and it's been clearly demonstrated.

But the bad news, let's say, or the in terms of application, is that first it will depend: the performance in sprinting will depend on the performance on the distance you select, which means that for a different distance, there will be some differences in the optimal, let's say, profile, which is very different from jumping. Because jumping is just jumping. Sprinting, "sprinting" doesn't mean anything to me, because a 5 meter is totally different from a 30. You agree with that?

So that's the first bad news. And the second bad news is that for most distances, the optimal profile is something that is very, very far from the typical human standards. So in terms of programming, I would not—we are doing some research to dig deeper—but in terms of programming, I would address things exactly as you proposed: having a group reference or a level reference, having some normative values within the group or with external references measured with similar devices, and having my own references.

We usually, when we work with team sport players, we usually use the median of the group on two or three main variables, and we bucket players like: is above or below the median on that variable, that variable, that variable. And then for the training, we always ask the question: do we need that variable to be improved? Yes? No? Then okay, we don't want to improve everything for everybody. We just want to improve what's necessary in the context.

James de Lacey38:31

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What variables are you looking at? Are you looking at ratio of force on that, or you looking at just some of the other mechanical variables like force, velocity, power?

JB Morin39:56

No. So to me, in most sports where acceleration is key, we tend to look at two things: the maximum force output—the maximum horizontal force output—and indeed the ratio of force. Because the ratio of force will tell you if the maximum force output is coming from a high force capability with an average or a bad—

Orientation capability or the opposite, a very good orientation capability of an overall magnitude of force that is lower. And until you measure that, there's no way you can estimate that. If you and I reach 5 meters together, it absolutely doesn't mean we have the same combination of magnitude of force output onto the ground and orientation.

You might be very good in terms of magnitude of force produced but very low in terms of orientation. So to think simply, you push hard in the wrong way, but because you push hard there's still a component that is horizontal. And I might be exactly the opposite. I push much less, but it is crazy well-oriented forward. And until you decipher between these two, there's no way you can have that from just checking our 5-meter times.

James de Lacey40:59

You just reminded me of the horizontal force debate. I haven't thought about this in a while. And there's been, same thing with the force-velocity profile, same thing, a lot of detractors about us saying there's no such thing as horizontal force. You just turn the stick figure on its side and that's horizontal force.

Maybe just dive into that for me. Okay, for me, let me explain my understanding. And I think my favorite way of, I guess, countering that, at least in my head, when I was talking to Matt Bryce about this a few years ago, he linked me a study showing the difference in muscle activation based on a vertical jump versus a broad jump and how much more the hamstrings and glutes are involved in something like a horizontal jump.

Which means it's not just turning a vertical to a horizontal stick figure because that muscle coordination is so different. So there has like, it can't just be the same. Maybe just dive into it, maybe explain it far better than I did.

JB Morin42:00

Taking your stick figure and rotating it to say this is the same thing in the other way is absolutely not serious, in my opinion, because it would mean that you also rotate the gravity field. Are you really rotating the gravity field and the application of gravity on Earth? No, you are not.

So to me, to summarize things, it's very simple. It's, there is no horizontal force, it's correct. There is the ground reaction force, there is only one vector. But because it's oriented in a way onto the ground, it has some components, and we can have two components in the sagittal plane of motion—one that is vertical and the other one that is horizontal.

So for example, if I jump in place, I tweeted, I did a full slide with that a few months, years ago, that's very fun. If I skip in place on my force plate, there will be the ground reaction force and there will be no horizontal component, there will be only vertical component.

Now if I skip and I move forward, there will be the same amount of force because my body is pushing down the ground the same. But because it will be oriented forward, there will be a component that is vertical and there will be a component that is horizontal. That's the component that will allow my center of mass to move forward.

And now the funny thing is that if I skip the same, I'm able to skip and move backwards. And you will see on the force plate that the vertical component is exactly the same, but the horizontal component is the same but negative. It's oriented backwards.

So it means that in sports, every sports movement is two things: how much force is impressed to the moving body and what's the orientation of the force. So instead of saying, I agree, instead of saying vertical force and horizontal force, we should say vertical component and horizontal component of the ground reaction force depending on the angle of application of it. But in terms of simplifying things, yes, we do say horizontal and vertical force. But sometimes when you simplify things without reminding that at the very beginning, you might sound nerdy and so on, but still that's more biomechanically correct.

James de Lacey44:17

And then you get books written about you trying to disprove a concept.

JB Morin44:17

Very easy to take any concept and say there's no such thing as X and Y. That's super easy to say.

James de Lacey44:17

For sure. Just to round off this podcast, more general question around power training. So first one, optimal—you talked about kind of like you give a lot, say, general power training to tennis players. I want to dive into what that means for you. But before that, optimal power load. Do you subscribe to the idea that training at a load that maximizes power in that exercise should be quote unquote prioritized within a training program to maximize power for that player, or you kind either in the spectrum? How does that look for you?

JB Morin44:49

You mean in sprinting?

James de Lacey44:49

Just generally. So let's just say, yeah, like you do a load-velocity profile and there's a load there, et cetera.

JB Morin45:18

Yeah. Basically the thing is, the thing that's very important is that if you are able to measure power accurately and instantaneously, okay, you will maximize power with almost any type of load. The question is how long will it last and so on.

For example, if you do sprint cycling, you start sprint cycling, you have any type of resistance, at some point you will reach a peak power and it will decrease and so on because you're pedaling too fast and so on. So it means that you can reach maximum power with any load, and you can stimulate, by definition, power with any type of load, provided that you have the maximum intensity.

Now the question is, with some loads and for some profiles and people, you can have a better, let's say, stimulus overall. I'm giving you an example. If I run with a sled of 10 kilograms, I will run super fast. So if you measure my running power, let's say quasi-power accurately, I will have a peak at some point and then it will decrease because I will produce a lot of running velocity, but my force output will be lower in the direction of motion.

And then if you add more loads, maybe I will stay in that maximum power zone for a bit longer. And this is why we think that some loads are better than others. But in terms of developing power, I think that any load in the spectrum can be used.

James de Lacey46:47

Perfect. So in terms of, let's just say, general power training for tennis, since you're working a lot in tennis now, how would a—obviously very general question because there's a lot of things going on—but how would, say, a general program look? And are there certain exercises that you typically lean towards for you to develop just general power?

JB Morin47:19

So basically for tennis players, except if they have good reasons to work on the lower limb push-off power, we usually want to cover the court more. So to have more powerful displacements on court, very first approach that we have is to improve power in explosive movements of one, two, three steps.

So for that we work a lot on, for example, starting sprints out of lunge positions, starting sprints with loads and so on. We want their one, two, three steps pushes to be as powerful as possible. And we always include in the program some unloaded situations that are closer to the tennis movements.

But there again, if you think that you're going to improve a movement power by just doing some sprints without resistance, that's going to work with beginners and untrained people. You're going to get some results. But at some point you're going to have to overload the system because the same thing will not result in gains more.

So we are very specific here with tennis players because for the players I work with, the margin of improvement is there. We don't even care yet about profiling them. We usually use that general type of power training. And then with the most skilled ones and when performances start to plateau, we're going to think further with the individual profile.

James de Lacey48:26

Does your exercise selection then gear towards that kind of vertical-horizontal component for that ground reaction force? So you don't care if it's purely vertical-based exercise or purely horizontal-based exercise? You're just looking to do something with high intent?

JB Morin49:03

No, we do both. We do both because they have some working time at the gym. So the idea is to work both on the non-specific, non-sprint-specific type of loading power, if that makes sense, with some type of loaded jumps, loaded CMJs, very explosive deadlifts and so on, trap bar deadlifts and so on. And then we move on the sprint-specific type of maximum power. We try to combine both.

Because they also spend some time at the gym. But what you said is very important. We always focus on quality and maximum intent. Maximum intent to me is the key to developing power.

When I see some athletes squatting and it's not heavy, it's not fast, and there's not many reps, so it's not endurance, I say it's neither maximum strength nor maximum power nor endurance. What is it? It's nothing.

James de Lacey50:06

Junk volume.

JB Morin50:06

Junk volume and fatigue for nothing. And sometimes also this will make them a bit bulky and so on, and a bit tired. What's the point?

James de Lacey50:06

Exactly. So are there certain sports then where you would maybe gear more towards, say, a horizontal-style power—let's just call it, let's make it basic—horizontal-style power training versus a vertical?

JB Morin50:40

As for example, in some sports that needed—yeah, I wouldn't say, of course it depends on the sport because some sports have some very, very horizontally oriented specifics by definition. But it also depends on the athletes themselves, because sometimes when the—let's say that the athletes have a very, very high requirement in the horizontal direction, let's say bobsled pushers and everything—you might with some of them do some non-horizontally oriented type of work because they need it. They need that unspecific type of development because they really start from scratch and you don't want to be fully specific there.

But then at some point with some athletes, when that type of nonspecific work is just a maintenance type of work, you know that you're going to focus a lot on the horizontal projection and so on. This is what you do basically with most trained people.

James de Lacey51:42

Perfect. I think that's everything I wanted to ask you here, JB. But where can people find you and follow you and keep up with what you're doing?

JB Morin51:42

Very last thing, if you allow me—yes, go. That has not been published, but some case studies will be published here and there. We have some results of professional elite NCAA athletes, professional rugby players, improving their sprint capability even after years of professional training by focusing more and better on that horizontal projection and things. So it's there, some margin of improvements.

Where can people find me? Basically social media—X, Twitter, Instagram—and my website, jbmorin.net. And I tend to publish there the research that we produce, the research that I find interesting. So that's the way.

James de Lacey52:14

Awesome. And I'll link all those up in the description and people can follow you there. But thanks for coming on, JB. I really appreciate it.

JB Morin52:46

Cool, my pleasure.