From Research to Real World: Testing & Training Athletes for Elite Performance w/ Paul Comfort Ep 48

Episode Summary
In this episode of the Athletic Performance Podcast, Coach Ryan Patrick sits down with Professor Paul Comfort—author, researcher, and one of the leading voices in strength & conditioning science. They unpack the real-world application of force plate testing, the myths around strength thresholds, and how to make smarter programming decisions.

✅ When and how to introduce isometric testing for youth athletes
✅ The truth about “how strong is strong enough”
✅ Why jump ratios (RSI, DSI, EUR) can mislead coaches
✅ Programming lessons from rugby, soccer, and pro athletes
✅ Why periodization is a blueprint, not a rigid script

Links & Resources

• Connect with Coach Ryan Patrick 
• Follow Professor Paul Comfort - X | Research Gate
• Subscribe on Apple Podcasts / Spotify / YouTube

Chapters

• 2:00 Paul’s Origin Story
• 7:00 Youth Athletes & Force Testing
• 14:00 Belt Squats, Iso Squats & Testing Variability
• 17:00 How Strong is Strong Enough?
• 22:30 Plyometrics, Tendon Stiffness & Myths
• 29:00 Context Matters: Sport Demands & Positions
• 30:30 Force–Velocity Profiling
• 35:00 Ratios (RSI, EUR, DSI): Useful or Misleading?
• 43:00 Building Capacity vs. Expression
• 45:00 Periodization Myths & Realities
• 49:00 Agile Periodization in Practice
• 52:00 Research Limitations & Quadrennial Plans

Transcript

Paul Comfort: 0:00

Hopefully at the end of the four week block, you reevaluate your athlete and you either go, awesome, they're where I expected them to be. We can carry on. Mm-hmm. Hopefully you don't go, oh, they haven't improved as much. Let's modify what they're doing. What you really want is why they've improved more than I expected on everything. Now I need to modify what I plan to do because we're further ahead of where we were. Right. That's the ideal situation.

0:30

That was Paul Comfort, professor, author, and one of the most respected researchers in strength and conditioning. Chances are, if you're involved with athletes and elite performance, you've come across Paul's work, whether you realize it or not. Now, Paul's reputation in our field is huge. He's published probably more papers than most coaches have written training program. And unlike a lot of the research out there, I feel that his really has work that can translate to the gym floor. And that's why I wanted to bring him on to bridge the gap between academic theory and what coaches like us face every day. So in this episode, we cover when you can start testing young athletes, why strength thresholds aren't as simple as squat twice your body weight. How periodization is less Soviet science project and more of a flexible framework, and we even talk about why force plates are the gold standard compared to jump mats. Please be awesome and make sure you subscribe to this podcast. If you've already subscribed, please drop a five star and a five star only review. It helps keep the podcast growing, helps me find great guests who want to come on and keep sharing great information with coaches all around. Let's get into it.

Ryan Patrick: 1:46

Welcome back to the Athletic Performance Podcast. I'm the host, Ryan Patrick, and today's guest is speaker, author, professor, researcher Paul Comfort. So man, um, thanks for taking the time. I know you've got a intensely busy schedule. We already talked off air about, uh, how many articles you're producing, so, um, the fact that you're able to carve the time and, and put this on your schedule means a lot to me. So, really excited to have you here.

Paul Comfort: 2:12

No problem. It's a pleasure. It's always nice to be able to, um, you know, share some of the information, and some of it is the stuff that you won't get reading a journal article because you're so restricted with what you can put in there. So it's always nice to have these conversations.

Ryan Patrick: 2:24

Yeah, my biggest beef with going back to, to reading the research journals is, uh, really checking myself on methods and statistics, which is like the least exciting part of it, but probably one of the most, I.

Paul Comfort: 2:37

Yeah, definitely. And, and the methods, you know, sometimes you do look and they can be a bit sketchy, which is, can be excusable, you know, decades ago because maybe we didn't know any better. Um, but certainly, uh, you know, when you're looking at some of it now and you're thinking, ah, yeah, you haven't done that. Right? You know what, what bug bear for me is when you see, um, see somebody say that they've, they've followed ASEP protocol and then you actually have a look and go at, at the protocol they say they followed and then what they've described and they're totally different.

Ryan Patrick: 3:04

Yeah. So I actually saw, I got an email right before I hopped on this podcast that references a recent study that you had published looking at the Nordics versus the R dls and their assertions were a little bit different than I felt that your guys were in the research paper. So I know people are always trying to get away with a little bit more than maybe what's there. But, um, to kind of kickstart this, for those who don't know about you, could you give us a, a quick origin story on, on you and, and kind of bring us up to speed on kind of where you are professionally?

Paul Comfort: 3:34

I like the way you framed that as an origin story. That's good. Uh, so I started off, uh, 30 ish years ago. Um, strengthening conditioning wasn't a thing in the UK back then. Um, the UK Strengthening Conditioning Association is just over 20 years old, or almost 21 years old at the moment. Um, so it really was more personal training background and starting off doing that, but working with two extremes. So I ended up working either with athletes that wanted to get better, which was either football, soccer, um, or rugby union at that point, or, uh, generally, um, overweight businessmen had a lot of money to spend and would happily spend a lot of money to try and get in shape, then go on holiday for three or four weeks and come back and have to start from scratch. Um. As soon as I got the opportunity to get involved, uh, with organizations like the NSCA and do their um, CSS qualification, I did that. And then, uh, I was asked to help become a founder member for the UK SCA. So I started off initially just sort of personal training while I was studying, doing my degree, and then doing my master's degree. Then started working in universities, um, and combining that. Luckily with working with athletes. So it was always university teams or local teams that the universities had partnerships with. Um, I've now been at University of Sulford for the last, I think I'm in my 18th year now. Um, so no matter what I say about it, it must be a pretty good place to work.'cause you know, I've been there 18 years, so started there, um, completed my PhD while I at the University of Sulford. Um, did that via publication and was lucky enough when I first started there to have time dedicated to working with some of the teams that we had partnerships with. So I'd get a few mornings a week to be able to go in and get the hands on experience. But the nice thing with that is not just gaining the experience, um, and impacting what they do in practice, but also then saying, well, okay, some of this research doesn't work here. We can't apply it in this way. So how do we tweak it? How do we change it? How can we make the, the research far more? Um. Applicable to, you know, applied sports situations, which has been a fantastic opportunity to be able to do that all the way along. Um, yeah, so sort of 30 years later, um, or just over 30 years later, I'm where I'm now as a full professor at the University of Sulford, um, got a small research team working around me. We're really lucky if people don't know where Sofer is, it's just on the outskirts of Manchester. So I live pretty much in the middle of Manchester and Liverpool. So you can imagine there with the, with the soccer teams, you've got a hell of a lot. Not just the Premier League, but all the rest in this area is pretty extensive. Um, you've got a couple of rugby union teams, almost all of the rugby league teams. There's one in France and one down in London, but the rest are all pretty much around this area within a 90 minute drive. Hmm. Um, so it gives us a real high density of sports teams to, to work with, conduct, research with, send our students out on placements and lots of practitioners to talk to, which is great because actually they're the people that drive most of the research questions we come up with along with some students. There's occasionally a student go, why do we do it this way and not this way? And you go, no idea. No one's compared the two directly. Right. Let's do it.

Ryan Patrick: 6:47

That's great. Well, um, you know, like I said before, it's um, with the volume of research you have, it seems like you're the godfather now where you've got a lot of people you can co-author with and, and pump that stuff out. So clearly you got a good team. But, um, I kind of wanna go back in time and talk, um, maybe six years. I don't know how long that is in research world. Seems like a lot these days. But one of my favorite articles that, um, you published on was the standardization and methodological considerations for the i isometric Mid the Eye Pool. We're seeing this, uh, current era of force plates being commercially available to a lot of private sector strength and conditioning coaches like myself. We're seeing a lot of guys start to play with this data, and I still think there's, you know, just maybe some misunderstanding about some of this stuff. But I want to talk specifically because I work with a lot of young developing athletes who maybe don't even have armpit yet armpit hair yet. They're just getting their feet wet in the weight room. And from what I want to know is from a pragmatic standpoint, how young can we start them with something like an isometric mid thigh pool? And when does the improvements or the changes actually, when should it start to inform program design for us? Well, I

Paul Comfort: 8:04

think you, you can start'em as soon as they're competent at performing the task. Um, and if you look, there's a study by Dr. Ops, um, in the Journal of Strength and Conditioning Research where she's, sorry, something's just going wrong with the audio then. I don't know what it was. That's good. Um, so, um, yeah, so Sylvia Moops has then looked at this, uh, using the isometric mid five pull, um, in a whole range of, of gymnasts. So, um. Looking at the data, the, those that were pre peak height velocity. So prior to maturation, uh, really interesting because their average age is eight years of age, but the standard deviation, so if you've got plus or minus two, uh, you know, you've got people that are six years of age and younger. Now they're gymnast. They can move their body really well. So that might be a little bit different to, you know, somebody at the age of six who's, you know, just started playing rugby or, or whatever the sport might be. You know, tag rugby or something like that. Uh, but as long as they're competent and as long as they're coached really well, it should be pretty simple. You know, you've gotta get'em in the right posture and then you've gotta cue them appropriately. Again, the, the biggest issue you get sometimes with the isometric mid five pull is, it probably wasn't the best name to give it. Weightlifters know what a mid five pull is. Nobody else does. So some people will try and take the bar down to mid five, which for most people is too low, depending on your anthropometrics. And if you tell a weightlifter or a powerlifter to pull what they're doing in something like a deadlift or a clean is pushing through the floor with their feet. You got somebody holding a bar that isn't familiar with those tasks and tell'em to pull and it all becomes upper a body. So you've gotta be really cautious on how you, you coach'em to do it. But you can start at a really young age, um, and. You know, the one thing to look at is, does force continually increase If you do five or six trials on isometric, midy pull, and the, the force slowly increases on each trial, you are not reaching a peak that's just familiarization. And one of the recommendations is, is to keep performing the trials until the peak force across multiple trials is within 250 newtons of each other. Now, there is a limitation that with that, that was first put in place by Professor Greg half and Professor Mike Stone when they came up with a test back in the 1990s, and they published the first study on it back in 1997, which most people forget partly because they university staff keep telling people not to look at old research. And obviously that's pretty old now, but that's where people should go and find, you know, the, find the original stuff. Um, and in that situation, um, when, when we're looking at, at this data, if you've got 250 newtons as a threshold, well if you've got a 6-year-old. How much force are they really gonna produce? 250 Newtons could be a quarter of the force they're producing. Whereas if you're working with a weightlifter generating seven, 8,000 newtons, 250 newtons is minimal. The problem is, is then what threshold do we use? And no one's looked to that. It's actually something I've discussed with Professor Greg HA couple of times. But now the nice thing is with the automated force plate systems, you can, you, it instantly, they instantly analyze the data. Some of them will even tell you the percentage change between trials. Mm-hmm. So then maybe we go with a less than a five or 10% change. And then we keep that as, uh, as, um, the appropriate and the appropriate trials to, to use and identify that there's no more learning effect in terms of, you know, when can you use that for programming Again, I think as soon as you've got a stable measurement and you know that, you know, within a session, and then ideally if you test them on a Monday. Monday next week and Monday the week after, and you're still getting similar, um, variables. Um, you know, the, the peak force is, is comparable between weeks. The Rapid Force production is comparable. We can definitely then start saying, well, okay, this, this is a true reflection of their maximum force production capability. But like you do, you know, you wouldn't program off a, off a one RM with somebody really young and inexperienced who, um, might be capable of performing it, but you know that every time they're gonna perform it, they're getting an adaptation partly through skills. So they're getting better each session. Um, so yeah, once that stabilizes, then I think you can start using it for programming. The main thing is though, how, how precise do we need to be with programming with really young athletes? You know, I mentioned sort of 6, 7, 8 years of age for them, we want it to be fun. Um, so just give them a whole variety of different things. Don't obsess too much. Make it fun. Develop their toolbox so that they can perform that whole range of exercises you really want'em to perform when they're an older, um, athlete and really trying to make performance improvements. Whereas, you know, at that young age, it's let's just teach them how to perform all the tasks, whether it's in the weight room, whether it's jumping, sprinting, changing direction, whatever it might be. Um, but it will still give you an idea. You know, if you look at somebody's isometric, mid five pole peak force and it's really high, but they've got a really low can movement jump, it's pretty obvious. We need to start focusing on their more ballistic capability. Or if you look at, you know, counter movement jumps, good. ISO Paul is good. Reactive capability and a rebound jump if that's really poor. Oh, there's, there's somewhere we need to be focusing on. Um, so sometimes we can keep it really, really simple. Uh, but certainly once you get up to those, um, more experienced athletes, and I'm saying more experienced, not older, um, you know,'cause you could have an athlete who's got a 10 year training age, age 16, and you could have somebody who's, you know, early twenties who's only got a three year training age because all they've done is play the sport beforehand. Yeah. Um, and it's then once you get athletes that are performing really well, that's when we really need to interrogate the data a lot more and start looking at some of the more nuanced metrics we might get from the ISO pool or from a jump test or whatever else we might be assessing on,

Ryan Patrick: 13:52

have they looked at, um, because the, the one about the gymnast is really interesting to me. I'm gonna have to look into that, but has there been any investigation of some of the other isometric, uh, force testing methods with younger athletes? Like, uh, maybe the belt squat, iso, or, um, some of those.

Paul Comfort: 14:09

No, I've not seen much in younger individuals. It tends to either be the, uh, predominantly the isometric mid thigh pull, and that might be in sort of youth soccer players in the uk There's a couple of studies where they've done that across multiple age groups with males and females. Um, occasionally you'll find the isometric squats. Belt squat is something that's relatively new in terms of research. Mm-hmm. And, you know, there's only a handful of studies on it. The protocols are all slightly different and that always happens. Mm-hmm. Um, you know,'cause you might start collecting your data and nothing's been published and suddenly you publish your data and five other things have been published at the same time. Um, but there's, there are some issues with it. While we get a really, really, really high force, you get true lower body force production. Uh, there is no weak link in the chain. Mm-hmm. Whether it's an iso squat crate, that compression, so you don't push as hard as possible or, you know, upper body, uh, and trunk. Not being able to maintain posture during the O pool sometimes. The isometric belt squat really gives us a true maximal effort. But, uh, we've played about with multiple protocols and the best option is to use a full harness like you can get from a, um, a K box or any flywheel device.

Ryan Patrick: 15:20

Yes.

Paul Comfort: 15:20

If you just use a strap across the hips, if you are generating a lot of force, that creates a hell of a lot of chafing on the lower back on the inside of the thighs. It's not good. Mm-hmm. And you only notice that when you step in the shower. So, so you, and again, but then the problem is next time you test somebody, they don't put a max effort because they know how uncomfortable it could be. Mm-hmm. So the, the four harness is much better. The problem is we can't get reliable rate of force development or four set time points. There's always giving the system whether you're using a chain or anything else, and then the give within that, that harness. Um, we just can't get the rate of force development to come out as as reliable, um, which is problematic. I'm sure at some point somebody will find a solution to that. Um, maybe it's something that has to be custom made, which is a bit more rigid, but still gives you the, the comfort that you need. Um, but certainly in young athletes, I've, I've not seen anything with a, with a belt squat.

Ryan Patrick: 16:13

Yeah. But then in that situation, I think we're almost back to like strapping the force plates to a leg press to type device and just having guys, you know, jam on that.

Paul Comfort: 16:21

Yeah. And again, that, that's problematic'cause you know, look at the different types of leg press devices we can get. The angles you'll be at the joint angles change every time. Yep. Actually attaching them to a leg press in itself is a, is a hell of a challenge depending on the force plates and the leg press. Um, so yeah, you know, you're then looking at a totally different, um, task that you're assessing. And unfortunately none of them could be used interchangeably. So if somebody's using one, whether it's an iso squat, belt squat, iso pull, whatever, whichever it is, they've gotta stick with that same task. And you can't compare to other data it's been collected in those other tasks.'cause they're completely different.

Ryan Patrick: 16:56

Making this hard for us, Paul,

Paul Comfort: 16:59

just stick with the same thing you're doing and continue or yeah, if you think that you need to use a different protocol, and this is the same with things like jump testing as well. Yeah. If you think you need to change your protocol, ignore all the historical data that you've got, because if as soon as you change it, you end up with, you know, completely different, um, force time characteristics.

Ryan Patrick: 17:16

Yeah, that's absolutely true. And then of course people are trying to compare the jump mats with forced plates and it's just two totally different things. But you know, specific to the jumps and the ballistic stuff, um, through some of your work, we see that the, the mid thigh pool, max force may not necessarily modulate counter movement jump height, which is obviously one of the most, uh, researched and utilized tests on force plates, especially in the private sector. But that it, the, the mid thigh pole might actually, um, influence some of these reactive measures that we see with like a rebound counter movement jump. So I think the question, and, and you've already alluded to this a little bit, that, that we're all asking is how strong is strong enough? And at what point do further strength gain stop translating to speed, power, or deceleration improvements?

Paul Comfort: 18:09

Yep. Um, it's, it's the typical answer of it depends, you know, it depends really on how strong they are. So I, I've got data on athletes where they're generating really high forces. You know, you're looking at 50 newtons per kilogram in their relative peak force, um, or, or back squatting, you know, double body weight for, um, squatting full depth. And in some of those situations, chasing after more strength at that point probably isn't the best option because then we look at things like the counter movement, jump height, the rebound jump capability, and it's just nowhere near as good. So we know, then we need to focus on those other aspects. That's pretty clear. But then with other athletes, we, we've had one athlete in the past who, um, absolutely phenomenal performances. Uh, he was getting, I think it was. Over 60 newtons per kilo on the isometric mid thigh pole. Wow. Squatting two and a half times body weight buts had a 65 centimeter canter movement jump weighing 125 kilos. So you look at that and go, wow, okay, what do I train now? What should they focus on? Because ballistic capability is fantastic. Maximum force production is fantastic. How much of an improvement am I gonna get in both of those? And that's when you really need to start looking in detail and go, well, how do they achieve that? How long does it take them to achieve the peak force in the isometric mid thigh pull? Mm-hmm. The curves, slope of the curve is not steep. We need to focus on rapid force production and then also how, how long does it take? Average time to take off in the counter movement. Jump for the squad of athletes was around 700 milliseconds, right? This athlete, 1.2 seconds. So 1,200 milliseconds, half a second longer. So he is jumping out, jumping everyone. He as go on the squad out, jumping everyone, but it takes half a second longer, so that means somebody else could jump. He tries to react to that. They've jumped, caught the ball and started running and he's not left the grind. So that's problematic. That's not what we wanna see. Um, so in that situation, we can look and go, okay, it is rapid force production is the problem here. Mm-hmm. So we need to focus on, you know, is it jump strategy? And this guy was going for, you know, 50 plus centimeter counter movement depth. So a big range of motion. No surprise he was taking so long. Right? So then you can focus a lot more on, well, we need to maintain that strength level we definitely wanna maintain is jump height, but we need to do things to improve how quickly you can do that. Now interestingly, if you look at the work that, uh, pro Kmy published in 2010 and 11, she actually showed in people that weren't strong, the best way to improve their jump performance was not jumping, it was just to get them stronger. So what she, what she reported is that basically the unweighted and braking phase that she termed, um, eccentric instead of braking, um, that duration reduced. So the unweight quicker, they dip down faster, and because they're stronger. Through strength training, they can hit the brakes harder, so they decelerate quicker. So that, um, the unweighting phase and the braking phase, the duration decreases and in some cases then the propulsive phase might stay the same, same duration, but you've suddenly had a big reduction in, in, um, time to take off. And that's what we found with this rugby player. After preseason training, he'd gone from. Um, you know, his 65 centimeter can me from jumped, taken 1.2 seconds and he got down to 700 and something milliseconds and his jump height dropped by a couple of centimeters that we were fine with that. That's okay. Oh yeah. You know, he,'cause now he's out jumping everyone but within a same similar timeframe and the improvements it with him all came from that reduction in um, the time that it took to on weight and the time it took to hit the brakes and decelerate. And his propulsion phase also reduced very, very slightly. Um, so because of that reduced duration in the propulsion phase, that might explain a slight reduction in jump height'cause he's not got as much time to apply an impulse.

Ryan Patrick: 22:09

Sure. Um, to ask kind of a clarifying question, a lot of the, the research seems to stratify stratify between the weaker and the stronger athletes. So, um, and I know this is hard because the populations vary wildly, but does there seem to be some minimal threshold, maybe how many Newtons per kilogram that we should be looking to kind of take off the table first in terms of pure strength before we're even worrying about ballistic stuff?

Paul Comfort: 22:37

Yep. There's nothing really, um, you know, there's pe people have said previously, you know, uh, 1.5 or two times body weight back squat to do right. Biometric training. Uh, personally I think that's, I think that stems from people using the term plyometric training as a, as a catchall for jump training. Mm-hmm. Because if you think about it, plyometric training, reactive short contact time, fast stretch, shortening cycle is ankle dominant. So why do your quads and glutes need to be really, really strong apart from from that leg stiffness? Because most of it comes from the elasticity in the tendons and a little bit of false production from the, from the plantar flexors, but actually with a very high intensity, fast stretch shortening cycle task. The majority of it is elastic recoil, um, to get down to those really short brand contact times, so. I think that sort of, you know, what's the minimum threshold that people have come up with in the past? No, no one's done it as far as I can see with a isometric mid thigh pull. Um, for squatting, you know, people throw this, this value around a 1.5 or two times body weight. But for if you were doing depth jumps, you know, if you are jumping off a box, a meter high and you're going into a, you know, a decent angular displacement of the ankle, knees, and hips, squatting down, taking, you know, 5, 6, 700 milliseconds to jump out of that, if you are dropping from a meter, you're gonna hit the ground with a pretty high force. The, then the momentum's gonna be high. So you need to be quite strong. Yeah. But if you are just dropping off a 30 centimeter box. And then doing a depth jump. I think most people can probably cope with that. Um, and you know, you watch children doing it when they're playing even. Mm-hmm. Set up an assault course they can do it no problem. The reactive aspect, I think you'd probably be better looking at what's the minimum threshold for plantar flexor strength to be able to be really, really reactive.'cause actually, if you look at some research and the, the author's name's escape me at the moment. But if you look at that for the plyometric tasks, there isn't actually an eccentric phase. So we'll refer to it as an eccentric and a concentric phase. Right. Really short contact sub 200 milliseconds. What you tend to find is on a couple of studies where they've put, um, ultrasound on, on the muscular tenderness junction of the gastric anemia, um, is as they're about to make contact with the floor. The calfs are already shortening. So you're already going through a concentric action. Um, and you're already starting to plantar flex at that point. So you're actively, you know, plantar, flexing into the ground. That means when you make contact with the ground, you lengthen the tendon from proximal and distal end. So the rate of lengthen in this phenomenal, but that means the elastic recall is huge, as long as the connective tissues can cope with that. Um, you know, and you'll, you'll see, go on social media and have a look. You'll see people jumping off things one up to two meters high rebounding with a short contact. Mm-hmm. Don't go and try that unless you've slowly built up those jump pipes. Don't just go and see, let's see what I can hit.'cause you're gonna rupture something. Paul.

Ryan Patrick: 25:31

Paul, I'm almost 40. I'm like worried I'm gonna rupture in Achilles every day.

Paul Comfort: 25:38

Yeah. I feel your pain there. Um, so yeah, I think one of the things is we, we need a certain level of strength, but I, I'd certainly wouldn't say even with younger athletes, I wouldn't say get a certain level of strength first and then move on to. Ballistic plyometric, you need to do all of it.'cause you need to develop the skill. Yeah. You might not get a huge amount out of the ballistic plyometric training until you've developed a certain strength level, um, so that your muscles, tendons, et cetera, can cope. You can perform the tasks as efficiently. The higher the height you are falling from, whether it's a ballistic or a plyometric task, the higher the momentum. That means you need to produce a ridiculously high force to decelerate and then rebound.'cause you've only got a short time. So you need a certain level of strength, but you probably need a good balance of let's get people strong while developing the technique and these other exercises, um, for the B ballistic comply metric tasks. And once the strength level's going up faster than the performance in those tasks, emphasize those. Mm. And then if they're catching up the strength, let's push strength up again. You know? It should be, it should be relatively straightforward. I'm gonna do myself, I have a job here. Um, but it should be relatively straightforward to be able to do that. And I think, so sometimes when you look at the research, you know, like you said, people will categorize as stronger and weaker. The problem is, there's some studies, there's a couple, and I, I won't call them out here, but there's some studies where, uh, if you look at the research and they say stronger and weaker, and you look at the stronger group and you're like, wow, they're still really weak. Mm-hmm. Yeah. If you, and you know, you look at that in soccer players, we've, we test probably about a thousand soccer players during the start of pre-season. Every year we've done that. Multiple years, and the only people we find that are strong are the goalkeepers. The rest of them, they can have a fantastic ballistic imply metric ability, strength levels, relatively low aerobic capacity off the dial, most of'em phenomenally aerobically fit. Oh yeah. So the easy thing to improve for them is get'em fitter and not sorry, get, get them stronger. Mm-hmm. Whereas if we flip that around and look at rugby players, actually for some of those it's no, they're really strong. Mm-hmm. So we might need a bit more ballistic or plyometric or enhance the aerobic capacity depending on the role they play in the game. Um, so it's, you know, it's always a difficult one. What, what's the sort of minimum threshold? I don't think there is. What's the maximum threshold? Again, I still don't think there is. It's just looking across that continuum of different exercises or, or assessment methods we use with the athletes and saying, well, where's there a deficit? You know, if you are ridiculously strong, keep chasing the strength. When your plyometric ability is poor, it's probably not the most sensible option, although you do have to, and I've had this question a few times, you do sometimes have to think about certain sports so forwards in rugby union in the UK when they're really heavy and sometimes don't sprint more than 10 meters, do they really need to work on the plyometric ability? And it's the same with, you know, some of the American football players, some of'em are huge, and all they do is accelerate five, 10 yards, boom, straight into somebody again, do we really need to work on plyometric ability with them? And you will find some that no matter how you coach'em, they can't get a short contact time. They're just not used to moving in that way. Um, but then we need to look at, well, how do they play their sport? How does the coach play them? How does the coach use them? Would spending time on that physical characteristic enhance their performance or not? And you can't say, you know, for one specific position, yes it will, or no it won't because the coach plays them differently. You know, I've seen prop forwards weighing 130 kilos plus in the UK in rugby, some that play the entire game, and they do cover. Decent distances when they're sprinting others never go over 15 meters and only play a small portion of the game. So you've got two totally different people there, and the coach will use them in a different way. Um, so you also have to loop in the coach and all the other staff say, well, what do we do with this individual? What, what do they need to improve? And surprisingly, a lot of the time, the coach can tell you what they need to improve. You do the testing and go, yeah, okay, you saw that. Didn't quantify it in any way. We couldn't measure it, but they might have said, this is where they're limited.

Ryan Patrick: 29:46

Some of the, those guys we've had, like the NFL linemen, um, they're just ground-based mammals, man. They're not, they're not getting, they're not getting much air no matter what you do. No, but I think you've, you've addressed one of the, the big concerns, um, that I've seen strength and conditioning and, and we've had sort of a renaissance, at least in America, where all of a sudden we're focusing on what's going on below the knee. It felt like for a long time it was, you know, get that one and a half to two times body weight squat because that's what you need to do, plys. And, and we kind of ignored, like we did some calf raises and stuff, but we didn't really do plyometrics, especially some of these, um, I would say more extensive approaches where we're kind of building just, uh, baseline, um, extensibility, the pretension that you talked about that's really necessary for getting some of these, uh, kind of elastic, uh, return on investment when it comes to the plyometrics. But I kind of have one more question about this. Um, how strong and strong enough, um. Does the, does the force velocity profiling change your approach to any of this, or are there some criticisms with that, that maybe people aren't aware of when trying to, to use this to solve some of these deficits that athletes are having?

Paul Comfort: 30:58

Yeah, so with force velocity profiling personally, uh, and the research I think is really interesting. Personally, I don't use it with athletes because it takes far too long to do it. Mm-hmm. And if you look at most of the research, it's done on a Smith machine, not done with free weights. And if we're assessing the velocity, it's then much more reliable on a Smith machine, you don't really go into many gyms where they've got 10 Smith machines where you can assess an entire squad quickly.

Ryan Patrick: 31:22

Yeah.

Paul Comfort: 31:22

Whereas we can go in, we, we can get comparable findings. We've done a little bit of top pilot data collection looking at the, the normal force velocity profiling with jumps across different loads. And then we've looked at. Do we identify people's, um, sort of prior training priorities differently If we do just do something like, um, an iso pool, an countering movement jump, um, or even if you've got minimal equipment one RM back squat, an countering movement jump. Mm-hmm. And actually you can normally pick those people out. Because you know, somebody who's, um, got a certain profile on the falls velocity curve, you then look at those other tests and you go, okay, really strong, poor jump performance or weak, but really good jump performance. Mm-hmm. Well, the jump tells you the velocity'cause at the higher, the velocity, you leave the ground up when you take off the higher the jump pipe. Um, and then you've got a measure, an actual measure of strength rather than something you've predicted from the velocity you're moving up, um, during, um, force velocity profiling. Uh, so I think you tend to end up getting exactly the same information, whichever approach you use. And we find that, like I said, we go out and test multiple squads of athletes, uh, as soccer teams pre-season. It's a ridiculous number that we, we end up testing and you can get through a quarter of 30, uh, pretty quickly. But what we'll do is we'll take a six or seven sets of force plates. So we'll do isometric mid thigh pulls, and we'll have a couple of stations set up. CA movement jumps with one or two stations, set up a rebound task with one or two stations set up, and if they want single joint isometric testing, we'll we'll throw that in as well. But we can get through without a number of force plates. We can get through an entire squad in under an hour. And then 20 minutes later, they've got the reports on. Well, this is, hey, squad's performing. Um. I don't think we could do it that fast with, um, forced velocity profiling. Uh, so yeah, we've tended to, to stick with that. And I know some people, um, especially training individual athletes, do a lot of force velocity profiling and that that might be more effective for them, uh, and certainly is feasible in terms of the, the time that it takes. Uh, but what, what I see from the pilot data we've collected is they generally tell us the, the same thing. Um, and it's only, it'll be the anomalies like the one athlete I mentioned where you'd really have to interrogate the data much more mm-hmm. To really find out any, any nuances. And again, the nice thing that I really like with doing something like a canes movement, jumping and ice. So pull is we can look at those other characteristics. You've got your peak force, but let's also look at force at a hundred fifty, two hundred, two hundred fifty milliseconds in the isometric tasks. Okay. You've got your counter movement jump height, but let's look at at least. Let's have a look at the time to take off, and then if you might wanna break it down, and then start looking at the duration of each phases or the impulse produced in each phase. Um, most of that though, as soon as you start interrogating it in more detail, you don't feed that back to the coaching staff.'cause most of them wouldn't know what you're talking about. Right. Um, so you give'em the basics, tell'em the training priorities, and it's just that one or two people per squad where you go, okay, we need to look at this in more detail. Because either they're phenomenal everything, or they're really poor at everything. If they're really poor at everything, but they're a really good athlete, you know, they're great at their sport. Mm-hmm. How do they cope and what do we really need to focus on that? Um, and sometimes again, you have the issue that it's, they can't be bothered, you know, they're at the top of the game. Testing means nothing to them. They've got a contract no matter what. Right. They're not gonna change the way they train, so they just don't put in any, any, any effort. Although when you get them in a, a team environment and start testing, it's really interesting because a lot of athletes only go, you know, who's jumped the highest, who's got the highest force, and suddenly you'll get people that, uh, we've seen this numerous times. Suddenly people that didn't put in the effort at the beginning where you thought, yeah, they're really not. Even though I've really tried hard, they come back afterwards and go, hang on a moment. I'm at the bottom of the pile. Can, can I go again?

Ryan Patrick: 35:12

Mm-hmm.

Paul Comfort: 35:12

Um, so, you know, there's always some limitations for that.

Ryan Patrick: 35:16

Yeah. Uh, you get some competitive bodies together, especially at that level. I, I love seeing that. One of the things we're kind of dancing around, I think as well, are some of these metric ratios. So the, the popular three that I see most commonly talked about are, are RSI, the Eccentric Utilization Radio and the Dynamic Strength Index. And I think there's always some, you know, some downside to metrics because you can kind of finesse it like. You know, especially with the simplest one with RSI, it's like the jump pipe maybe didn't go up, but the ground contact got faster so it looks better. But I guess from your perspective,'cause I know you've done a lot of research with this stuff, what are the most valid and reliable and how can they kind of mislead coaches when we're just looking at, at, at a ratio?

Paul Comfort: 36:03

Yeah. Okay. So I think the fir first thing is something like the eccentric utilization ratio. Um, you know, where it's that the, the difference between their counter movement jump and squat jump performance. So you've got one where they're using a stretch shortening cycle. One where you've supposedly eliminated it. You test people on force plates and have a look at the number of trials they need to do to do a squat jump without a small amplitude counter movement. Oh, that's tough. So we, I used to use it quite a lot. Uh, I've definitely moved away from it now because it, you, you might take 10, 15 trials to get an athlete to perform it without doing a counter movement, because naturally in most tasks they do, they perform a can movement so that, that becomes problematic. The other thing is, is that we're assuming that the difference between those tasks is that one uses the, the stretch, shorten and cycle, the other one doesn't. But actually, if you video somebody when they're performing it, look at the difference in the joint angles. So what you tend to end up with is, um, a more upright trunk and a squat jump. Um, whereas with a counter movement jump, you can swing your trunk forwards'cause of the momentum, then swing it back up, you end up jumping higher. Then because of the trunk motion, you've, uh, different joint, uh, angles while you've gone through the task. So we don't really know. If you are getting a higher jump height because of the use of the stretch shortening cycle, or actually just you went through a different range of motion, et cetera, and how do you standardize that? You can't standardize that during your can to movement jump. You'd almost have to go, well, let's look at what they do when their can to movement jumps, and then we'll get'em to form their squat, jump to a to the same depth. But if you start looking at the depth, they go to an counter movement jump. It'll vary slightly between, um, testing sessions and then you'll not compare and like would like if we then start doing that with a squat jump. So eccentric utilization ratio, like I said, I used to use a lot, but the more I've looked at it and the more we've tested on force plates and the more we've gone, let's not bother. It's not telling us what we want it to. And no matter what you try and do to standardize, um, the, the, the, the squat depth during the cage movement jump or the squat jump, it still doesn't give you what you think you're getting so that we've tended to scrap and leave to one side. The other metrics, you sort of answered the question. Um, when you said about RSI, and this is the same with DSI, they're a ratio. So what happens if RSI stays the same? You do a training intervention, RSI is exactly the same. Mm-hmm. But you've had a proportional change in the components. So the jump height and the um, grand contact time have both changed in proportion. So your RSI is the same. Your coach would look and go, well your training had no effect. Actually you could had a higher jump height, but you might have had a longer, grand contact time. Mm-hmm. So the RSI is still the same. All that can flip right the other way. And again, sometimes you, you know, what, what is the ultimate thing that they want to see? Uh, when you feed back to the athlete or the coach, most of the time it's the height they're jumping. So why not just report the jump height and the time and the grand contact time, or if it's an accounts movement jump and you're looking at some like modified reactive strength index, um, look at the jump height, look at the time to take off if you've got the components that we really need to do to calculate a ratio.'cause if we look at the ratio alone, that could be really misleading.

Ryan Patrick: 39:20

Yeah.

Paul Comfort: 39:21

Um, and it's the same with the Dynamic Strength Index. You could, you know, I get people saying to me quite a lot, especially if I present on that, that topic at a conference. What's the ideal? Well, if there isn't an ideal, it will change. If you do a focus period of time where you are, you know, an eight week block of maximum strength, guess what? Peak force goes up on the isometric task. It doesn't go up in proportion on the counter movement jump. So your DSI changes and you then suddenly go, okay, we need more ballistic. So your DSI has dropped. If you do a period of much more ballistic training and they're focusing on, um, ballistic plyometric chain training, the peak force normally in the jump goes up. Therefore your DSI, um, also increases. And suddenly you say, yeah, we need to start working more on their ability to generate maximum force. So it. It tends to show us what we expect it to. So you can't say a set ratio is gonna be ideal. All you can do is look at that and go, well, okay, what should they emphasize? But again, as I said a moment ago, if you've got their peak force or the relative peak force during an isometric mid thigh pull, and you've got their force during an counter movement jump, do you need to really work out that ratio? Because if you think about it, if somebody could have a ratio where it says they need to work on their ballistic capabilities, they could be down at, uh, you know, the 0.5. Mm-hmm. So they're expressing 50% of their isometric peak force during a dynamic task. The counter movement jump. But if their relative strength on the ISO pull is 20 newtons per kilo, I could do that stood on one leg. And I'm definitely not an athlete. So if they're weak, we just need to focus on getting'em stronger. Yeah. Um, and like I said earlier, if you look at that research by, um, pr, call me, getting somebody stronger improves the on weight and in the braking phase. You end up with a much higher force during the propulsion phase. So if they're weak, just focus on getting'em as strong as possible while developing that technique and those ballistic and plyometric tasks. So I think the problem is, is you get a lot of people go, I need one. I need one metric. I would need one variable. Mm-hmm. Give me one. It doesn't work. It's the same as if you look at things like, you know, functional movement screen was really popular for a while. Oh yeah. Um, but people look at the composite score or you can perform average on everything and get a relatively high score. Or you can perform phenomenally well on some things and awful on others. And you've still got the same composite score. Those two athletes are not the same. No. And that's what ends up being missed here. You can't just, we don't wanna look at hundreds of metrics. Look at all the automated force plate systems now. They'll have a hundred plus for counter movement jump. Some of them are, um, uh, over 150. Yeah, some of those metrics make no sense whatsoever. Some of them are duplicates, but we can probably boil it down to, you know, maybe five metrics that we need from each test for us to really, uh, figure out what the athlete needs to focus on. And then it's, as I mentioned earlier, then thinking, well, what do I feed back to the athlete, to the coach, the athlete's parent? If they're a youth athlete, what will they understand and what's most important for them? But then there's all the stuff that you can look at as a strength coach or a sports scientist to say, okay, this gives me a bit more detail. This is a bit more nuanced, but you probably only need that in the really well trained athletes.

Ryan Patrick: 42:38

Yeah, it almost what I'm here, like the way I'm interpreting what you're saying is we're not, let's say you're looking at the dynamic strength index, it almost is like a, uh, way to describe like, is this athlete explosive at this level of strength? And then we change the strength, which in my mind is giving them more potential capacity long term. Obviously we wouldn't see the ballistic stuff go up that much. It's like, okay, we've reached a new threshold of strength. They're not really tapping into that. So now we wanna make sure that they're explosive at this new level of strength. Yeah. So just, just kind of a way to modify that.

Paul Comfort: 43:16

Yeah, definitely. And I think, you know, you, you've described that really well there and there. There's a few things to think of with that because you'll get some people critiquing some of these different tests and going, well, okay, you increase peak force on uh, an isometric mid bipolar, you increase back squat performance. But jump, jump, height didn't improve to the same magnitude. Mm-hmm. Well, why would it, they're completely different tasks. They're, they're totally different skill levels. Right. The neurological side of things is completely different. You know, again, you sometimes get people saying, well, you know, peak force on the ISO pull went up by X amount, but my squat only went up this amount. Again, they, they're completely different. You have a sticking point in a squat, whereas with an ISO pool, you put them in the strongest position they can possibly, uh, being to perform that task. So you are not gonna see a linear increase in all of those. But by assessing each of those different characteristics, you can then say, this is what they need to focus on for the next X amount of weeks, months, whatever it might be. Um, and like you said, it's, it's increasing that strength level to increase their capacity. Mm-hmm. Once you've increased their potential ability, um, you know, to generate high forces during a ballistic or plyometric task during sprinting, whatever else, let's train that task.

Ryan Patrick: 44:27

That makes a lot of sense. You're, you're looking at these differences, you know which one needs to go, and then like, it's, you know, training. I mean, this concurrent idea is really great, right? We wanna do everything to keep a threat of similarity, but there has to be a time where you focus on whatever a specific priority is, and being okay that this, this ratio might not look favorable, but it's kind of for the long haul you have to kind of make that concession at least for a short period of time.

Paul Comfort: 44:56

Yeah. And I think, you know, if, if, if you've have a look at, uh, professor Greg Hafts new book on periodization, that's a really interesting, um, thing that he discusses within there in terms of the different styles of periodization. Mm-hmm. A lot of the myths relating to it, but block periodization in its truest form where it's Right, we just focus on strength, forget everything else, just strength that can work in some sports, that can work really, really well. But if you are working in team sports, whether competing regularly. You can't afford to drop one of those physical characteristics completely, right? You still need to do a little bit. You almost need, well, what's the minimum amount we need to maintain that characteristic while we increase the other? Uh, because you can't improve them all simultaneously unless you are pretty much untrained and then everything improves no matter what you did. Mm-hmm. Um, so he discusses, you know, the differences between the block approach or an emphasis based model. Yeah. Where you have that period of time where you really emphasize strength. So X percentage of your training in a week is strength, really high load, but you'll still do a little bit of ballistic and plyometric type training within there, but it's just enough to keep things ticking over. Um, and again, sometimes you might have limited time, so you might focus on strength in the gym, but then while they're doing their field or pitch or court based warmups. Great opportunity to do a bit of plyometric and ballistic training within that warmup. So you still have that small amount to keep things ticking over. Uh, but it, it's really interesting the way that, um, Greg Haf presents similar in, in his textbook and challenges some of those sort of philosophies of, it must be done this way, it must be done that way. Sorry, we've gotta be realistic with this. Yeah. Curious. Um, you know, we, we've gotta make sure that what we're really doing is suiting the programming and the periodization to that individual's requirements.

Ryan Patrick: 46:46

Yeah, it's, it's often a moving target, right? Um, yeah. One of the things I like to say when I'm talking to, like my staff is, you know, every program we're designing, we're trying to address whatever the, the highest leverage point or the limiting factor is, and guess what, at the end of this program, it's probably going to change. So I think like the, I mean, I remember early on reading, you know, Tudor Bomba, and I'm looking at these Quadrennial plans thinking, and like, I've never designed one of those. Like, it just, it never intuitively made sense to me to plan that far out. But what I'm finding more and more is with this surge of data that we're getting, especially stuff that's more reliable, um, not imus and stuff, but like force plates that we, we can actually trust some of this, that we're able to. I mean, almost be a little bit more dynamic with the prescription of stuff because we can catch this early. And I think, uh, you know, John Kylie was, I think that's his name. Dr. Kylie was, yeah, was one of the first kind of, uh, criticisms of periodization and in planning.'cause to your point, my athletes have so much stuff. I don't know, like their coach just might get pissed off one day and make'em run 20 gassers. And then that completely just kind of shits on what I have planned for from a training standpoint.

Paul Comfort: 48:01

I think there's a couple of really interesting points you, you've raised there that you know Yeah. Most people don't develop a quadrennial plan'cause most people aren't working with Olympic athletes. If you are, you know, if you are working with rowers, it's what makes that boat go faster. You know, the distance they've gotta cover, you know, an average stroke rate. So, okay, if they've got a certain stroke rate, what's gonna make it go faster? More force? How can we generate more force? Let's start looking in detail, what muscles have to be larger so they increase force generating capacity. Mm-hmm. And then we can start planning. And with that you can also look historically, you know, where, what are the performances like 20 years ago? How much have they improved over time? Can we model that and say, well, okay, for the next Olympics you, you've got a gold this year. In four years time, we've gotta be here to still be hitting gold. And then what do we need to do to try and improve that? And if you look at sports like rowing, if you look at British cycling when they were in their heyday and winning everything, all of that was modeled, including the technology, et cetera. Most of us don't do that.

Ryan Patrick: 48:58

Right.

Paul Comfort: 48:58

But then the other point you picked up on is, you know, sometimes you have to change what you're doing. And I think the problem is sometimes people see programming and periodization is, I've set this, we're following it blindly. And it, yeah. If they've just been made to go and run 20 K on a pitch or the, you know, the coach had them doing suicides up the court or across the pitch or whatever the sport is. Mm-hmm. You've suddenly gotta change what you have planned. And sometimes the best thing to do might be go right, but we'll just start a recovery session. Ice baths, protein shakes done, relax, because you've just been beasted. And we're gonna get nothing outta this training session. But I think that's the thing is it's your periodized plan is a blue. Some people talk about agile periodization. The whole point of periodization is you have a plan, but you should react to it. So if you plan a four week block, you don't blindly go straight into the next four week block. Hopefully at the end of the four week block, you reevaluate your athlete and you either go, awesome, they're where I expected them to be. We can carry on. Mm-hmm. Hopefully you don't go, oh, they haven't improved as much. Let's modify what they're doing. What you really want is why they've improved more than I expected on everything. Now I need to modify what I plan to do because we're further ahead of where we were. Right. That's the ideal situation. Yeah. Doesn't always happen. Not often. Again, you know, team sports. Then you'll go, well, okay, the average of the squad, they've all improved like I expected. And they've got five people that didn't improve as much, and five that have gone way above where I expected, then you've gotta manipulate some of those individual training plans. So I think that's, that's part of the issue is people don't always understand the difference between program and periodization. Mm. Um, Kylie is a couple of studies that all reviews that he put out were very interested in thought provoking. The only problem is it didn't provide a solution.

Ryan Patrick: 50:43

Right.

Paul Comfort: 50:44

Because these are the problems with it. Okay, brilliant. That's great. So what do we do instead? And also that, you know, there's always, you know, with those people that attack periodization, there's always a, a bit of a sort of mismatch in their understanding and how it was traditionally meant to be. And you've gotta manipulate it for team sports nowadays, rather than Olympic sports. And also you can't just, you know, you can't objectively defend every aspect of periodization either. You look at all the studies that say they did a periodized training program, most of them haven't done a periodized training program. Most of them have got. Two, four week or, or three, four week blocks of training. Right. There's a handful of studies where they followed them over a year or more and truly periodized everything, not just the training they do in the gym, but what they do on the pitch, the core, the technical and tactical work, the conditioning, everything that's built into that. Their true studies on periodization. But there's a handful and most of'em throw in the term periodization and it's, that's a 12 week training program that's not periodized.

Ryan Patrick: 51:48

Yeah. It's one of the big drawbacks with any of the research Right. Is the time because Yeah. Even if, even if you've got the budget, I'm sure, you know, having, uh, athletes actually do what they need to do for that length of time is hard.

Paul Comfort: 52:02

Yeah. You know, you think about it, if you're doing at a, if you're trying to do that with, uh, with any athletes, there's a nutrition rate. If you're doing it with professional athletes, which is what most people would like to see, right. Because they're the ones where we can apply it, you know, more widely, well, they regularly move teams. How frequently do you see people? So you're certainly not gonna get more than a season because suddenly half your score could change. At the end of the season, people retire, new athletes come through. So it does make it really difficult to form, and I'm not making excuses for people, but it's, it does make it very, very difficult to do that. And that's why I think some of the early stuff, which is not research as such, but where people have described, um, one, two, up to four year plans on the run up to an Olympics or a world championships with a very sno small number of athletes normally in, in textbooks. Um, they're really, really useful. But that's the only place you're really gonna get that.'cause those athletes tend to stay where their coach for an entire, you know, Olympic cycle, et cetera. But it's one individual, um, which that's not necessarily a problem, but it's not what we traditionally see as research. But we still need to look at that information and, and use it.

Ryan Patrick: 53:10

I think that's, uh, goes back to what you highlight as one of the benefits with being between Manchester and Liverpool is that you've got all these practitioners out there who, you know, are, are trying and testing this stuff in the field.'cause ultimately those are the guys that have to get results and Yep. You know, we have to make, uh, informed decisions whether or not we have these research studies to support it wholly. Yeah. Um, I do wanna ask a, kind of get back to some of the force plate, um, testing questions. So we've talked a lot about these bilateral tests. I-M-T-P-C-M-J are these sensitive enough to inform us about unilateral performance? Obviously we can get left right imbalances, but are we missing important details for athletic development or injury prevention? Um, without doing a true single leg type of, uh, test. Yes,

Paul Comfort: 54:02

definitely. Um, because they don't translate perfectly from a bilateral tasks to a unilateral task. So we are missing something. The problem is the unilateral tasks are inherently less reliable and more variable in nature. Mm-hmm. Uh, so, you know, something as simple as single leg counter movement jump, that's really difficult to get somebody to stand completely still on one leg for at least a second before they perform the task. Mm-hmm. Which is what you need to do for the way that the automated force plates analyze the data. Or even if they're not automated, you should still do that. You got somebody to stand on one leg with a leg extended so they're not already slightly flexed, and then therefore they decrease their, their, their center of mass height, which would inflate jump height. Um, it's really difficult. And then the other thing is how do you control it? So if you're doing a single leg cancer movement jump, what does the other leg do? And if you just, you get 20 athletes. To perform the task. Some will swing the leg and keep it relatively straight. Some it's, um, they'll swing it through, but they'll keep the knee very flexed. Mm-hmm. Some of them will just hold it in position and they want minimal use of it, but it's a bit like arm swing. Um, as soon as you throw an arm swing, everyone should jump higher. So if you learn how to do that single leg counter movement jump with an appropriate motion of, of the, the uninvolved limb, then you'll actually get a much higher jump height. Also, watch people and what a lot of them end up doing is not flexing in the knee a lot, and they'll put a hell of a lot of motion through the hip joint. That's not what they're do in their sport. So it's not necessarily then assessing their, you know, their unilateral performances they do in the sport. There's some nice research from, uh, Dr. Jeremy Shepherd who, uh. Is now in, uh, I think it's a Canadian sports institute he's working at now, where he did some stuff in the past with, uh, I think it was volleyball, might have been netball as well. Well, they looked at different jump strategies. So what they did is they did the normal bilateral counter movement jump. How effectively do you use your lower body? How effectively can you produce force during that slow stretch warning cycle task? But for the specifics of the sport, they also did it with a one, two, and three step approach into a single leg jump. That's exactly what they do in their sport. Perfect. Analyzing the data is much more difficult, um, because you need your force set in the ground. Most people don't have those. You've gotta be in a proper laboratory environment and then you have to understand how to analyze that data appropriately or you just use flight time, um, which misses a lot of the other data that we might need. Sure. To, to calculate. So yes, I'd say we definitely are missing information from doing the bilateral tasks, but they're the most reliable. Um, which means that if we wanna see a real change, for me, if I'm doing it with a squad of athletes, I can run a load of statistics. If you're working with an individual athlete, you need to know what the measurement error is. And if the measurement error on a single leg task is 20%, you've gotta see a change greater than 20% on whatever the metric might be. To know that's a meaningful change in not just variability in how they're performing it day to day. Um, so we're definitely missing something, but it's not anywhere near as simple as people think it could be to do some of those, those tasks. Um, and it's exactly the same sometimes you will say, but you know, in my sport, we always use our arms. When we jump in, so again, if you're looking at something like volleyball, so why don't we use arm swing, use arm swing, but do both. Do a can movement, jump with your hands on your hips, do a couple of trials, take your performance, then do it with arm swing. If you're only slightly higher with arm swing, you can just improve their performance by synchronizing their arm and leg action.'cause you should be jumping at least 20% higher with arm swing. Yep. Um, if not potentially more. Um, so there's, there's multiple things we can do, but it's how much time have we got to do it? Mm-hmm. Have we got the technology available to be able to do it and, and give feedback in real time. Um, and if you have, fantastic. You know, so if you are working at a sports institute, you're gonna have all of this stuff. But if you are working in a private environment or if you are working in a team sport environment, yeah, you're gonna have the force plates, uh, and other technology, but. Does the kit you have allow you to do some of these extra tasks, um, and keep a small measurement error, keep it reliable, um, and that I've not seen anything which has been published yet on how you should standardize some of those, um, single limb tests.

Ryan Patrick: 58:33

Got a couple follow up questions on that. It's got my wheels turning. Um, first, with respect to the measurement error, how do we, are there published. Data sets that we should look to? Should we be looking at our own data, data sets for this to, to really define like what, what percent change is actually meaningful Yeah. For their performance?

Paul Comfort: 58:57

Yeah, there is, there is published data. So if you look at something like an isometric mid five pull, uh, there's numerous studies which have included measurement error, and it seems to show roundabout or just less than 5% is the measurement error. Um, so greater than 5% change in peak force is a meaningful change across multiple populations within different sports. Ideally, you do want it in your own, um, athletes because they may be completely different in terms of the skill level, et cetera. Something like an isometric test is pretty easy though, you know, so the measurement error is always smaller. Um, and I've never seen anything above 5%. I've seen it down as low as, you know, two or 3%. Um. Same with something like a, a back squat. You do a one RM on a back squat or a power clean, the measurement error is less than 5%. So a change greater than 5% in somebody that's experienced in performing those tasks is a real improvement. That's great. Yeah. Um, things like the counter movement jump, um, and rebound tasks, depending on whether it's a drop jump, um, or whatever, whatever other task you might be. Again, you tending to see five to 7% in terms of jump pipe. Mm-hmm. Um, but again, that's much more complex'cause you can manipulate your jump strategy, go for a bigger range of motion, give you more time. Um, so that's why you tend to see a slightly greater measurement error.'cause there's far more degrees of freedom in terms of how you can perform the task. Uh, but yes, if you look across the research, you might find some specific measurement error data and some percentages. The worst thing is when you find something where it just says, you know, three centimeters in a jump. Okay, that's great. But three centimeters, if you can only jump 20 centimeters is a lot. Three centimeters when you jump in. 60 plus is nothing. Yeah. So it should always be expressed as a percentage, which I think sometimes people forget and that makes it much easier for us than look and go, well, okay, you've generated X value. Is it 5% higher? Yes, it is brilliant. It's a real change.

Ryan Patrick: 1:00:53

I know Matt Jordan, um, talks a lot about that and some of his, some of his work about, Hey, these are some of the metrics we wanna pick, because these, uh, measurement errors are not so large that we can actually trust and make some informed decisions based off of this. Yeah. Well, Paul, man, we've been, we've been going hard. I don't even think we got through all the questions, but I want to, we're gonna have to run this back another time, man. So I wanna hit you with, that's fine. A couple out outro questions. These will be, I think, a little bit shorter answer, and then we'll kind of wrap up with where people can find out a little bit more about you. So first, um, across your body of work, you have bridged research and applied practice better than most. Um, where do you see the next big leap coming for performance monitoring and transfer from lab to field?

Paul Comfort: 1:01:38

Uh, probably not from the research. I'd probably say it's from better education of practitioners. Um, again, like where I'm based, because we've got so many sports teams around, we regularly get asked to go in and consult. And even in the uk you know, from where I am, five hours, I can be pretty much five hours a drive in. I can be almost anywhere in the uk. So it's relatively accessible. Mm-hmm. Um, so talking to lots of different practitioners, one of the biggest limiting factors is with the use of technology. People buy it, who trains'em on how to use it. The person that sold at them who probably doesn't even have a sports science related degree, or if they do this might sound meme. Now, if they do, they're probably not a good sports science practitioner if they're in sales. Although, don't get me wrong, you some people earn a fortune doing that. So the problem is the level of understanding that a lot of people have used these technologies is somewhat limited. If you think about what's covered in an undergraduate degree in terms of the use of, let's say, force plate. Like we drum it into our students and hopefully they are much better than most practitioners that have got the same level of education because we really push home the establ standardize things. But I think that improving the education on some of these areas and teaching practitioners how to critique the research, which is out there. Mm-hmm. And that's simple things like what's the difference between if I use this force plate versus this force plate? Um, you know what? Does it make a difference? And yeah, it does. What happens if I can change some of the settings within it, you know, the, the threshold that detects the onset of movement in a, in a task. Yeah. That makes a massive difference. Um, so I think the biggest thing to then almost to feed back into the research with practitioners collecting really good, reliable, meaningful and accurate data is we need to be better at upskilling them. Um, and improving their level of knowledge and understanding. And I think that's where we'll start to see some improvements.'cause then we get that real world research. Feeding back in where then people can then say, well, okay, why does this work so well? Or why doesn't it work so well? Now we can tweak it in a more controlled setting and then it can go back and, you know, the pendulum will keep swinging with whether it's more lab-based, more applied. But that's, that's the area that I see is, is limited at the moment. Is that the real detailed level of knowledge and understanding of some of the technology? I used force plates in EX as an example, but it could be, you know, GPS, it could be mm-hmm. You know, wearable technologies, whatever it might be.

Ryan Patrick: 1:04:07

Yeah. I, not a lot of people talk about that, but you know, especially with these, you know, I use Hawkin Dynamics, love it. Great system. Um, but there is a concern of like, hey, when we're weighing in, I'm not deciding when this test actually, uh, or when this system feels like it has calibrated the weight appropriately. So I might get athletes rocking a little bit. Um, and it kind of normalizes it, but it's always, it's always worth asking that question of how clean is this data actually? And, um, especially as you start, Dr you know, stripping down to cheaper, uh, more consumer commercially available models, some of this stuff kind of lose, you know, you're using algorithms and stuff to make correlations to other pieces of technology, and it just, it can be unreliable at times. So I think that's, that's a really, uh, interesting answer. Um, one of the concerns with tech is things can quickly get, uh, really bloated and people can be confused. They can be tracking the wrong thing. So if you had to strip it back and give coaches just kind of one principle for assessing, um, and monitoring these qualities to actually transfer, what would that, what would that be?

Paul Comfort: 1:05:14

I. Actually make sure you are really assessing that physical quality you think you're assessing. Hmm. You know, so, you know, and again, that's as simple as let's do a max isometric strength test. If you've got force plates, let's do a ballistic task. Let's do something fast structural cycle, something more reactive, but actually use the right metrics. Use the right variables. Um, so perfect example of that counter movement jump. Everyone loves to report power. Um, but if you look at the work of, um, Linor, uh, he clearly illustrates, um, why there's a strong correlation between power and jump height. But the problem is, what can happen is you can change your jump strategy. Power can increase, jump height can go down or jump height can increase. Um, sorry, jump height. Yeah. Power can go up, jump height down or vice versa. Jump height can go up and power output can come down just from changing your strategy. Think about power is work divided by time. Mm-hmm. So if you dramatically increase the amount of work and you jump higher. But the amount of time has increased massively. That's not gonna change power in the way you want it to, right? Um, if you've got a, an increase in work, but only a very tiny increase in time or no increase in time, um, you've got an increase in power output and an increase in jump out. So that's part of the problem is people understanding some of the metrics and um, like I said, power is definitely not the best one. Intuitively, everyone goes, oh, I'm more powerful. Brilliant. But how do you then explain that to a coach if you're giving them jump, height and power and you go, yeah, the power one up. Oh, jump, height, decreased. That suddenly gets really complex. Mm-hmm. And you start gotta start talking'em through exactly how each of these things are calculated. They're lost, they're gone already. Um, and so it's really important to make sure you're aware of it. Are you assessing what you really think, think you're assessing? Or are you looking at something totally different? And I'll admit, I've done that in the past. I've published loads of papers where we've reported power, and now I'm going, why the hell did I do that?

Ryan Patrick: 1:07:15

Well, you're sa saving people's jobs out there in the professional world, man. So yeah. Doing the Lord's work. All right. Um, for coaches, you know, let's say they're gonna invest in a single piece of technology. Um, so obviously we can't get like, EC plates or stuff like that, but, um, what would you advise people to, to start with that that is reliable, that is not, you know, maybe a stretch for the average budget out there?

Paul Comfort: 1:07:41

The first thing, make sure you definitely do your homework and make sure you're getting something which does what you really want it to do. Um, if you can, force plates are probably the most versatile. Mm-hmm. Because you can do isometric testing, multi-joint, single joint. You can do, um, you know, your ballistic and your plyometric type tasks. There's so much you can, you can use with'em. Um, so if you, if your budget will stretch to that great option. But again, make sure you know you are, that you understand exactly what you're getting from them. Make sure you know, you know, most of these companies, it's a subscription package, right? So make sure you fully understand that, but also understand, ask them about what training they're gonna provide, uh, because it's no good getting the equipment if you're not using it appropriately, uh, because then you're just gonna be getting some pretty random data, which you don't fully understand. Uh, so. Not necessarily the tech, but the best thing you can do is, is invest in the education of your staff. I was at a conference in Ireland at the weekend and actually, um, somebody gave a presentation talking about how they'd improve things within Gaelic football. Um, and the biggest thing they did was bring everyone up to a higher level of understanding and education, getting them accredited in certain ways and suddenly everyone's singing from the same hymn sheet because we've all got a, a comparable level of education. So irrespective of technology being available or not available, you suddenly had a team that were all singing from the same hymn sheet, all wanted to do the same stuff. All understanding each other's thoughts and viewpoints while they'll be different. Um, so sometimes it's not even getting the technology. It's right. Let's get everyone's level of knowledge and understanding to a good level and, and mentor people. Now, if they're at that, that level, bring in the technology, you can do the same. You can go right, okay. You are gonna focus on the force plates. You are gonna focus on the velocity based devices. Find out everything you can upskill everyone.

Ryan Patrick: 1:09:32

Can't use a a, a tool to fix a personnel problem. Right, exactly. Alright, my man, I appreciate you so much. This was incredible. I'm glad we got to go into the weeds a little bit on some of these topics. So I'm hoping that people who listen to this, we'll, we'll get a lot of out of this and, um, if they wanna, you know, follow up with you or, you know, connect, find more about your work, what is the the best place to get in touch with you?

Paul Comfort: 1:09:57

Uh, they can either email me, um, which is P dot comfort@sulfordac.uk, or, um, I'm on, I was gonna say Twitter, it's not Twitter anymore. X and Instagram, uh, at Poor Comfort in 1975, which gives away my age.

Ryan Patrick: 1:10:15

Man, that's, uh, that's all right. X is still holding strong with some of the strength coach conversations, but, um, yeah, it can be, it can be hard to track'em, especially when people start commenting the comments and feel like I'm in a little bit of a scroll hole. But, uh, it's kind of lamenting the days when we had good forum discussions back and forth with, um, people, you know, the days of the, like the super training forums. If, if you're old enough to remember that. Yeah, I know I do. So, yeah, Paul, man, that's one

Paul Comfort: 1:10:40

of the things that's really good in terms of, you know, attending conferences and just sitting in the coffee shop or the bar and just mm-hmm. Discussing stuff with people. You learn so much doing that.

Ryan Patrick: 1:10:50

Yeah, the game has really changed since COVID. I mean, we used to at least have one kind of big annual event that we would go to, and it just seems like anymore it's, it's just hard to get on a plane, a train, or a car and, and get somewhere and, and just connect with coaches. But man, it's, if you're young and you're listening to this, it is the best way. To learn, just talk to people and just have conversations. So Paul, man, I appreciate you. I'm not gonna take up any more of your time, man. No problem. Thank you. This awesome. Thank you.