Welcome to the Empirical Cycling Podcast. I'm your host, Kolie Moore, joined as always by my co-host, Kyle Helson. Thank you, everybody, for listening as always. And please subscribe to the podcast wherever you're listening to it. If you have not yet, if you want to give us an iTunes rating or a rating on whatever platform you're listening on, that would be really wonderful. And the most wonderful thing would be to share this podcast if you enjoy it. And remember that we're ad-free, so if you want to donate and support the podcast, you can do so at empiricalcycling.com slash donate. We have the show notes for this episode up on the website, empiricalcycling.com. and consultation inquiries. Questions and comments, you can email empiricalcycling at gmail.com. We also have a little bit of merch at empiricalcyclingpodcast.threadless.com. And as a follow-up, after this episode goes up, we're going to be doing a listener questions episode on VO2Max next. And so I'm going to put up a listener questions thread on Reddit Velo for the questions, or you can email me again at empiricalcycling at gmail.com. So we have been kind of building up to this episode. is going to be on training your VO2max and ways to modify your training, your interval specifically, your workouts on how and why I think we should do certain things. So Kyle, some thoughts on VO2max maybe so far as well as kind of what we see as typical VO2max training strategies. So hopefully, if you've listened to the previous few episodes, you have a good concept now of what VO2 max is and how your body is actually delivering that VO2 to your working muscles. I think what is probably the most common traditional VO2 max training that people think of is like 5x5. Pretty cookie cutter. We're going to do 120, 125% of FTP for five minutes, five times in a row with, you know, some amount of rest in between and that's going to be our VO2 max bread and butter workout. I think you can find analogous workouts in other sport modalities as well. Okay, and so what about the effectiveness? of those workouts or maybe the perceived hardness or easiness of them. I think that varies. I know some people just dread VO2 work because it's going to be super, super hard and they think it's mentally much more taxing than a sweet spot workout, for example. But then I always remember myself when I was doing endurance training that I thought those 5x5 workouts were like super easy and I was not really breathing that hard throughout the workout and like I would even find myself like oh if it's supposed to be like say you're doing like a group workout or whatever because it's early season for collegiate. and it's supposed to be 120%, 125%, whatever. I would find myself upping it because I felt like it wasn't hard enough so I would just up the intensity to something that was actually a little bit harder even but I was like I, you know, maybe I'm just good at this thing so whatever. Yeah, so I think there's a sort of range of reactions that you get whereas like I feel like the reactions you get to a standard sweet spot tempo type workout are pretty much the same for everyone. Yeah, and that's actually one of those things kind of borne out by the data. What this episode is about, I kind of want to start it out with a quote that I read in a paper recently by David Montero and Carson Lundby. And I read this and I was like, yeah, that's me. That's me in a nutshell. That's everything I'm trying to do. So it goes like this. The ultimate goal of any area of physiology. is to discover the fundamentals of how a given function works, thus empowering to modify outcomes as desired. That is a good quote. I like that. But yeah, this is my entire approach in a nutshell, really. It's my coaching philosophy, and it's the idea behind this podcast, you know, to give all of you lovely listeners the knowledge to inform your training decisions, which is also why I know there's no such thing as miracle intervals. Sick of hearing about miracle intervals. There are no silver bolts. Yeah. But having said that, this podcast today assumes that you've listened to at least the last two, if not the last five now, Wattstock episodes. We're going to be referencing the studies and their conclusions or talking about things like stroke volume and blood volume, diastolic filling and preload, eccentric hypertrophy, diffusion gradients, and kind of assume that you know what's up. But don't let that stop you yet, though. You can still listen to this episode for the tips and get a pretty good understanding, but here's a very quick primer. So the terms that we're going to use a lot are preload. This is the amount of blood that fills the heart during diastole. Afterload is the resistance faced when the heart contracts to push blood into the lungs and body. So more preload. More blood filling before it contracts means more heart stroke volume because of something called the Frank-Styling Law where the more the heart is filled, the harder it contracts to empty it to the same amount or just about. The enlargement of the heart to increase its maximum volume and stroke volume is known as eccentric hypertrophy. And so when it comes to things like VO2 max, blood volume, peripheral adaptation, like mitochondrial density and whatnot, These are all kind of, you know, they can be short-term gains, you know, long-term improvements like a VO2 difference. And what we've really come to the conclusion of in the last couple episodes is that to physiologically improve your VO2 max in the long term, to really improve your number one long-term limiter, we need to focus on heart stroke volume by focusing on cardiac preload. Here we go with the terms, to induce eccentric hypertrophy and not afterload, which will give us concentric adaptations. I mean, according to the level of knowledge we have now, they're fine, but it's just not what we're after for long-term VO2 max improvements. So it's not like you have to avoid lifting in case your heart gets too thick. It doesn't seem like it's like that. And we could have just done one episode and stated all that in a little more detail. But I have learned to never take it for granted that someone will just believe something that I say. You know, likewise, we could have also just given you a short list of tips on how to improve your VAT to max intervals and just said good luck. But in my experience as a coach, answering everyone's questions about why really helps improve training outcomes and adherence to protocols. And, you know, even ideas for improvements or how to individualize the training. when people understand the point of it. And establishing the why is what we spent the last five episodes setting up. I always really liked this approach that you have coming from different sports, different sporting backgrounds. I feel like especially when you're a lot younger, you're just told to like do the workout. I mean, I understand it's a little bit different when you're, so you're in a team setting, like I was a swimmer for years, so you're not just working with one athlete one-on-one, you're working with 30, 40, maybe 50 at one time, and you're trying to prescribe a few different workouts to a bunch of different people, and so you definitely have less time, even though you're training 20 hours a week and you get face time with the coach the whole time, you don't have as much time to like explain why you're doing the things you're doing, and depending on the type of person you are, you may just be like, all right, coach, like, you know, they say jump, you say how high, or you could be like, middle of the workout, this is stupid, why am I doing this? I'm just gonna, I'm just gonna slack off for the, for the second half, because this is dumb, and I don't understand why I'm doing this. So, um, I fully support that, that notion that having a better understanding of the, the physiology, or the reasoning behind what you're doing supports the training and supports your, um, long-term development as a as an athlete. Yeah, and I definitely notice there is a spectrum, there is a spread of that in athletes where, you know, some of the athletes are very inquisitive, and I love that, by the way. They ask a lot of questions, why are we doing this? How does this work? And, you know, sometimes the answer is, I don't know, or I'll have to look up more on that, or, you know, or that's where we get ideas for individualizing the training even further. Or there's people who just say, okay, cool, just tell me what to do and I'll do it. And without question, they do it, which is also not optimal because, you know, you don't get that much feedback and you want to, you know, most coaches, I think, want to really make the training fun as, or as fun as it is useful. Ah, yeah. Yeah, so let's get this next thing out of the way first because I'm sure this is something I'd I actually don't think we've addressed this yet in the last five plus hours of talking. What are VO2max intervals good for anyway? So VO2max is the ability to move O2 to muscles. And it's the volume of oxygen that you can move to your muscles that is the ultimate limiter of O2 utilization. If you can move it, you can use it. And you can feel free to quote me on that. So at the end of this episode, we'll Get into some thoughts on the long-term interplay between like heart stroke volume and muscular adaptations and stuff like that. If you're confused about why, you know, utilization in the muscles is not the real long-term limiter of VO2max, I refer you to Wattstock number 20 on AVO2 difference. And so while FTP itself, I'm sure some of you are thinking, may be a better performance indicator, it's more highly correlated with better results in cycling. You cannot have a high FTP without having a high VO2 max. Like you'll never have an FTP higher than your VO2 max. Right. Due to various factors that we'll discuss in another episode, drink, it'll probably never get much higher than like 85% for most athletes. And some athletes I think are even lucky to be taking a sniff at like 80%. Like I was one of those athletes for sure. Oh yeah, for sure. Yeah, me too. So VO2max is necessary but not sufficient for high-level endurance performance. And necessary but not sufficient is something that you hear in a lot of areas of science. And, you know, the first person I heard say this is Andy Coggin, but I'm sure he heard somebody say something very similar. Probably Ed Coyle thinking about it now. But anyway, so this is why VO2max training is called Raising the Roof. If your FTP is 85, 86% of VO2 max, hammering more FTP intervals for another year might get you like a half a percent or 1.5 watts on a 300 watt FTP. But yeah, it's not much for your work. But if you can add 10 watts to your VO2 max on three or four weeks of training, then you get to add way more than one and a half watts to your FTP. And this is the part of the equation when I plan for athletes who are developing versus those who are already at their peak and kind of figuring out what's worth the time and the energy. So today we're going to go over ways that you can improve your VO2 max intervals. Any interval set is my goal. Really, with the goal of improving your long-term fitness ceiling. And we're going to talk a little bit about, you know, long-term, short-term underlying things of V2 Max and stuff like that. So I'm not going to give you the exact prescriptions that I give my athletes because they vary anyway. But, you know, kind of like the FTP training episode, you'll definitely get a sense of how I operate. And don't get me wrong, there's still a couple of things I'm holding back. I'm not going to give everything away. But as usual, I will attempt to convey an understanding of how I apply my understanding of physiology to the workouts that greatly increases their effectiveness. And also, don't get me wrong, these adjustments are probably going to hurt. A lot. Yeah. But in awful and wonderful ways that are not pointless. You and I make jokes about this all the time, but there's this very, very American Sporting and or exercising philosophy of Or just work philosophy too. Just work philosophy in general of if you're doing something and it's not working out, you're not succeeding, you should just work harder or the idea that an activity or a workout or an exercise is good for you because it's hard and because it sucks while you're doing it. And I think that this drives me nuts sometimes because like you have this you have this thing of like oh we're just gonna out we're just gonna outwork the other countries we're just gonna outwork the other teams whatever um and that's like not a universally useful strategy um I don't know if it's a cultural American thing but like I think of Rocky right where you have this training montage of Rocky like running in the in the woods dragging logs and stuff like punching beef carcasses yeah like like punching Punching frozen, frozen beef carcasses and stuff. And you're just like, America loves the, the like, the hardworking underdog. Yeah, hardworking underdog who's, you know, packing his own lunch and stuff. And then you even find that these sorts of things are pervasive through like, big time professional sports, these narratives of just like, gonna work really hard, blah, blah, blah. Yeah, if you put your mind to it, you can do anything. Yeah. It's true to some extent like hard work is good but like if you're going to spend time doing something hopefully it's more than just hard and it's actually beneficial like just because a workout is hard doesn't make it useful like I can go out and do you know I can put on a 400 pound vest and climb stairs but like is that and that's going to be hard but is that going to make me a better cyclist? Yeah, like you don't have to finish every session totally dead. And that's one of the things that we're going to talk about actually in periodizing. Well, we'll talk a little bit about periodizing this kind of work. But in terms of managing the fatigue of these intervals, we're definitely going to talk about that because I've mentioned this on the podcast probably more than several times, that I'm extremely conscious of how hard I make people work. and I don't ever want it to be gratuitous. I want it to have a point. This is all to say that there is a point to my methodology here and we're going to talk a lot in detail about how I find myself differing from a lot of the typical VO2max prescriptions. So everything that we're going to talk about today is targeted directly at increasing Diastolic Filling Volume to Increase Eccentric Hypertrophy Through Preload. And we're going to actually get to a cool study on that very shortly. So if you're not sure what any of that means, like I said, please listen to the last couple of Wattstock episodes and they all go into this in very great depth. These are also targeted at trained athletes. So if you yourself feel like you've hit a plateau that, hello, this is for you. But despite that, I've still gone straight for this type of stuff with VO2 Max on people who are relatively new to training, obviously not on day one, you know, when they're ready, you know, gradually introducing this, you know, this level of workload, but it's, I find it's been a very good decision in the long term because people develop much, much faster, and we'll talk a little more about that. The first thing I want everybody to get into their head when thinking about VO2 max intervals is to ignore power and only kind of pay attention to heart rate. We'll get into a little bit on why. So, for instance, like FTP intervals assigned as a certain percentage of FTP, these are varyingly effective or not effective. And in my experience, they are More often not effective. Because the better your sprint or one minute power, the more tying your VO2 max intervals to your FTP is a bad move. I mean, because VO2 is not linked to power output per se. Like there's no such thing as VO2 max power. And by this particularly, I mean, there's not like one number associated with, I'm going to ride at this. Level of Power, and I'm going to be at 100% VO2 Max. It doesn't work like that. Obviously, those of you who are, you know, reading a lot of the training literature out there know that there's a range of powers that can elicit VO2 Max. But the other thing here is that if your FTP is at some percentage of VO2 Max, then obviously your VO2 Max is at some percentage of your FTP, right? Yes, but only when we look at liters per minute. Like only when we look at things in terms of direct VO2 do they have this relationship. So when we look at power, the relationship between power output and VO2 in liter per minute changes with time. And we saw this in Wattstock 18 and 19 while talking about ramp test lengths, changing what people find as their quote-unquote VO2 max power. So for instance, in Wattstock number 19, we... talked about how a study did a three-minute effort, one-ass steady state, and they hit 100% VO2 max kind of right at the end, or the subject started with an all-out sprint, and they were barely pedaling at the end at like 200 watts, and they were at 100% VO2 max for like half of that. And by the way, this is the cover art for Wattstock number 19, so you can check out that graph right there. What about the slow component and VO2 and heart rate drift to 100% VO2 max? I personally avoid this approach to intervals because you can hit heart rate max without hitting 100% VO2 max or 100% diastolic filling volume and vice versa. So there's a lot of stuff going on under the hood that we actually cannot measure without some specialized equipment. So this is actually part of the reasoning behind the approach that I have is because we don't know certain things. And so in my approach, it's best to just go with what I am absolutely certain will affect your eccentric hypertrophy, as opposed to things that we're pretty sure, but we may not, we'll see in a little bit. So the relationship between heart rate and VO2 is better, but not great. And, you know, we'll see a study on this in a little bit. And my training strategies to kind of take care of these concerns, but here's an overview. So heart rate can change based on things like hydration, which affects blood volume, which affects preload, or caffeine, autonomic stimulation, or hypedness. How hyped are you? How amped up are you for this workout? Heat, sleep, even fatigue from previous intervals in the same session or even in the same interval are going to affect this. So for instance, in the Adami study referenced in Wattstock 18 shows the test group reaching an average VO2 max Uptake in the 30-second ramp stages, but with a heart rate 5 BPM lower than in all the subsequent tests. So they only hit 183 peak heart rate versus 188 for the rest of the tests where they did longer ramps. So this is what I'm talking about with the fatigue of the same interval. So that can affect your heart rate as well. So blood volume. We have a reference in the show notes, not going to get into this, but there's a study by Montero. The study does six weeks of endurance training on relatively new people. And all of the improvements, including stroke volume, are 100% explained by blood volume expansion and went away when phlebotomized. So they did all that hard work for nothing. So long-term effects in blood volume. also affects heart rate as we saw in the coil study that actually bridged the last two episodes together. So all this is to say that heart rate is better correlated with VO2 max than power, but not tight enough that we can say, for instance, if you don't hit max heart rate, you weren't at VO2 max. Or vice versa, we can also not say for sure you hit max heart rate so you were definitely at VO2 max, which is just not the case. So this is not an issue if your philosophy is different than mine. in which you are looking for more time at 90 to 95% VO2 max or heart rate, which is fine, but that's not my approach. And again, we're going to explain why in a minute. And also, we cannot say for sure that a given heart rate, and this is the most important thing, means a given stroke volume. So we're going to get into that in just a second. But the conclusion here is that if we just say, all right, 100% or 95% VO2 max or perhaps heart rate max or something like that, or Assign a Power Value. These are all emergent phenomena of multiple intertwined physiological systems. And that's the thing that we've been teasing apart in all of the episodes setting up this episode. Yeah, that makes sense. You kind of did a quick tour of a lot of things you've talked about last three episodes, but then also kind of bring it back to the idea that trying to measure the amount of VO2 max stimulus that you're getting just based off of power or heart rate numbers is, you know, iffy at best. Yeah. Or, as we're going to see in just a second, VO2. If we are looking at increasing heart stroke volume in the long term, we want to increase diastolic filling volume. And we can not say for sure that a certain VO2 is related to diastolic filling volume. So, alright, this brings us to our first tip. Tip number one, increase your cadence. Interesting. If you take only one thing from this podcast, take this, and that's why I'm putting this first. So the study is called Cycling Cadence Alters Exercise Hemodynamics. If you thought you could get a straight workout tips episode without diving into a great paper, you would of course be wrong. So... What are you, new here? For the new listeners, thank you for listening, and yes, we are always like this. This study took seven trained men with an average VO2 max of 70.5 plus or minus 3.6 milliliters per minute per kilogram. So, very well trained people. They had these subjects pedal at 200 watts, but they had them do it at different cadences. 70, 90, and 110 RPM. And the investigators measured... All the fun stuff. Stroke volume, AVO2 difference across the body, heart rate, cardiac output, that's Q, you know, product of stroke volume and heart rate, systolic and diastolic blood pressure, systemic vascular resistance, MAP divided by Q if you're interested, and VO2. So we have three trials of pedaling at 200 watts at three different cadences. So heart rate for all these three trials at 70, 90, and 110 RPM. varied. So it was 161, 163, and 169 BPM average for these three trials. So we see the heart rate going up with increasing cadence, right? I think a lot of people will be able to anecdotally confirm that kind of result as well. Yeah, definitely. And now let's think about why. So VO2 increased through these for the same power output. So the oxygen required, to put out the same power output changes with your cadence and increases with the cadence. So at 70, 90, and 110 RPM, it required 3.2, 3.4, and 3.7 liters a minute average, respectively. So these all have very small error bars, by the way, and they all have significant differences between them. So cardiac output for these cadences, low to high, 18.2, 21, and 24.5 liters a minute. That's pretty big. It's very big. And all you're doing is adding 40 RPM and you get to, you know, you're increasing your stroke volume by 6 liters a minute. It's huge. Yeah, yeah. So depending on how you want to do that number, that's either 30% or 25%, depending on how you're going to say it. Is it 18? 18 is either... 25% less than 24.5 or 24.5 is 33% more than 18.2, whatever. I trust your math. Yeah. All right. So now check this out. The systemic vascular resistance went down a little bit with increasing cadence as well. So that means less resistance to blood flow. But probably more interestingly, a VO2 difference went down. So this is across the heart, like the whole body. Not measured directly across the muscles, but it's a safe bet that there is probably some difference in the muscles. So why did AVO2 difference decrease as VO2 increased? So the authors don't go into this, but my educated guess for AVO2 difference is higher cardiac output at the same O2 requirement means the time component of the O2 diffusion, please refer to Wattstock number 20 for this, goes down. But since the flux of hemoglobin through capillary beds is much higher, the relative amount of O2 required per liter of blood is lower. So the delta of concentration difference can stay a little higher as well. This also explains the part of the increased VO2 difference a little bit too. Because the convective flux of hemoglobin is higher and capillaries are always operating at a much larger pressure delta, using smaller motor units, so lower force for higher cadence, obviously, that contract more frequently, and 60% more frequent contractions between 70 and 110 RPM requires more energy to move the legs in space, and even more energy as leg mass goes up. Sorry, sprinters. But also the protein CERCA, S-E-R-C-A, needs to spend a lot more energy because it's the one that mops up the calcium ions from inside the muscle cells and brings them back into the sarcoplasmic reticulum. So you need to spend a lot more energy to counteract that entropy. Again, refer to Wattstock number 20. All right, so the VO2 increase in and of itself is probably a good enough reason to increase cadence. Since for the same power output and you're using smaller motor units, to do a little decreasing of peripheral fatigue, we can actually increase VO2. And if that's our blunt instrument way of measuring effectiveness of intervals, we can increase their effectiveness just by increasing cadence. So if you want to work at a little higher percentage of VO2, increase your cadence. And in terms of the fatigue, believe me, and the people I coach, that the fatigue really does add up doing these intervals and I avoid it anywhere I can. So I've had more than one person say to me in just the last month alone that they felt like if they had been doing the same intervals at normal cadence, they would be completely wrecked. Interesting. And the higher cadence allowed them to keep pushing on the intervals once they got used to pedaling at a higher frequency. One thing I find interesting about this is that I always found, especially when I was doing more VO2 intervals as opposed to never, that I was definitely more of the type of person who wanted to do them at a little bit lower cadence. I find myself being more of a generally a higher cadence rider. If I want to cruise around, I'm more like over 90, 95, something like that. And I always found that like, oh, if I was going to do like hard three, five minute intervals that I would like drop the cadence a little bit to like mid 80s or something. Yeah, this is really, really common, actually. Yeah. And, you know, the thing that I've talked to a lot of people about with this is that they're saying, I feel like I cannot generate any power at higher cadences. And the answer is, you can't. Like, you just cannot. But, you know, despite the fact that your power output is lower, I said, don't think about power output with VO2. Because we can get better adaptations by increasing the cadence, even if your power output drops a little bit. And I'm going to tell you why. So if we think back and look at these slightly different heart rates for these three cadences, from 161 BPM at 70 RPM, Cardiac output at 18.2 liters a minute. And let's go right to the 110. At 169 BPM, putting out 24.5 liters a minute. So does this mean that stroke volume changed or not? Well, if you remember what happened at the last episode. Yeah, this was one of the hints from the last episode about decreasing cadence, decreasing cardiac return by the muscle pump mechanism. So what happened is stroke volume increased. So at 70 RPM, stroke volume was 114 milliliters a minute. At 90 RPM, stroke volume was 130 milliliters a minute. At 110 RPM, we're at 145 milliliters a minute. Wow. Yeah, this is awesome. So let's compare this about 8 BPM, let's call it 10 BPM to be generous, and compare it to the increase in stroke volume in the heart rate study from last episode. In this here cadence study, we're seeing about a 30 milliliter increase in stroke volume from 161 to 169 BPM. Let's just call it 160 to 170. Or about 15 milliliters of increase per Per 20 RPM. In the heart rate study, in the trained subjects, an increase in power output that raised heart rate from 160 to 170 BPM only increased stroke volume by 5 milliliters on average, or 30% of what we see by only changing the cadence without changing the power. Interesting. Yeah. So we get to increase stroke volume by 15 milliliters and only increase heart rate about 4 or 5 BPM. By just adding 20 RPM to cadence, that is extremely noteworthy because remember what we're after, we're after diastolic filling. You're after the stimulus in the heart muscle. Exactly. Self. Yeah. And so how and why does cadence so effectively increase stroke volume? We just mentioned this a second ago. So remember what we just talked about now and last episode especially, the muscle pump. and this being one of the determinants of cardiac preload. And so, yeah, so we definitely talked about potentially lower cadences, you know, on like cobbled sectors and whatnot, reducing it. But here's how that works in, you know, increasing cadence, increasing the muscle pump effectiveness. Muscle contraction squeezes veins and these veins have one-way valves and this squeezing increases the venous blood return to the heart and increases preload volume. And so why is preload volume important? Because of the Frank-Styling law. So the more your heart stretches, the harder it pumps. But we saw last episode that the untrained heart reaches a plateau. And in the trained, the heart apparently does not. Ah, yeah. Right? And so because of that, it's easy to induce adaptation in the untrained, where you just add plasma volume and stroke volume increases, and then at a certain point, you've got that plateau, right? and then, you know, just working above that plateau, you are working at your max diastolic filling volume and so we are sure that just working pretty hard, high heart rates, you know, high power output, high O2 or high VO2, you are going to almost definitely be getting some adaptation here because, you know, you're working at your max filling volume. Like, of course your heart's, you're trying to stretch your heart. But we saw in the COIL study on plasma infusion of trained subjects that they did find a max Stroke Volume, right? So infusing lost plasma in the detrained brought back stroke volume and some VO2 max. But in the trained plasma infusion and increasing blood volume, which normally increases stroke volume, you know, it resulted in no increase in VO2 max or stroke volume. So they apparently maxed it out. Your body naturally was already on top of it. Exactly. So my operating principle that's helped me successfully improve VO2 Max and people who thought they might have no more room for improvements, we're working on this. And we're working on inducing as much preload as possible with a combination of the muscle pump and everything else we're going to talk about in this episode. And so that not only will increasing cadence increase O2 required for the same power output, it will increase your stroke volume, which means it's much more likely. that our intervals are causing the adaptation that we want to our primary long-term limiter of stroke volume. So the additional VO2 and the muscle pump may hopefully expose a stroke volume plateau in some athletes, the same way that plasma volume infusion seemed to in the coil study with the trained athletes. And working over this plateau, if it's there, means that we are sure the heart will be generating eccentric hypertrophy stimulation. and more than it would be doing with more standard intervals. And, you know, think about this. We haven't talked about this in muscles, skeletal muscles specifically yet, but we cannot eccentrically load the heart muscle the same way we can load skeletal muscle, right? So you can lower 300 pounds on one leg, for instance, but that doesn't change the fact that you can only bring 150 pounds back up. because you can just load more weights and you can lower more and more weights because that's how skeletal muscle can work eccentrically. We can lower a lot of weight successfully but we can't bring it back up. But with the heart, we cannot pile on more plates. Literally, our only mechanism to induce eccentric hypertrophy is more preload. And that's why I've got higher cadence as the first and most important tip here. It's interesting because this is a little bit of a tangent, but I remember a long, long time ago, way before I was doing any of this, you know, reading a question on Reddit, someone said, well, okay, so if exercise, you know, the government says you're supposed to get a certain amount of cardiovascular exercise per week, like, why does, why, what is it about exercise? that makes it effective beyond just your heart rate going up. Like, why can't you just take a drug that, like, elevates your heart rate for 20 minutes four times a day, four times a week or whatever and get the same benefits? And, like, they were clearly missing all of this in addition to the fact that if you just sit there with an elevated heart rate, you're not actually utilizing more. Like, your muscles aren't doing anything. But I thought about that a lot when talking about this because, like, you know, There's so much complexity to some of this of what your body is actually doing and just looking at heart rate or power or something is simplifying and stripping away a lot of those nuances there. Right. And that brings me back, of course, to the quote that we started off this episode with is when you understand what's going on underneath, you know how to manipulate things in order to cause whatever adaptation you want. Right? Yep. And so with the increase in cadence, We actually have some more general benefits. You know, especially we get to use smaller motor units. And, you know, we've talked a little bit about this, but we haven't gone too in-depth with it yet. Obviously, learning to be comfortable while spinning faster is good for, you know, a track rider or being in a crit where, you know, it's easier to accelerate from 100 RPM than it is from 60. And we're also improving VO2 max that we absolutely need to work on for long-term adaptations, of course. Honestly, you know, like we said, you're not going to be able to put out quite as much power at higher cadence, but that's okay. The VO2 max and the stroke volume improvements that you're going to get in the long term are well worth it. But if we want to keep pushing stroke volume and cardiac output, there are additional things to do to increase the aerobicness and the cardiacness of our intervals. So tip number two. is to ignore power and go max. So we talked a little bit about this already. So I think one of the biggest mistakes that anyone makes with VO2 max work is assigning a power target. And we're going to, don't worry, it's not that simple. So hold on, let's get through this. Why? Because of what we mentioned, the relationship between power, time, and O2 uptake. I find that there are two types of athletes who have issues with usual power assignments. People with a ton of anaerobic capacity and people with a low FTP relative to VO2 max or people with no anaerobic capacity. So let's think about why. So if you have a lot of anaerobic capacity or quote-unquote FTP headroom, like your FTP is at like 70-75% of your VO2 max, it can take so long to get up to a decent amount of O2 uptake that you need to do 30, 40 minutes of intervals above FTP before you start breathing hard enough. And that is a ton of kilojoules and fatigue. And I've seen this with a lot of people too. Five by five, try it. Ten by five. Yeah, not kidding, like four by eight, five by eight. Let's kind of look at the dynamics of this. So as you start riding VO2, you know, it may only get to like 90, 95%. It's hard to tell without measuring directly. You know, especially without, you know, knowing diastolic filling volume, we cannot be sure where you're at with these. All right, so the big problem with all of this, I think, is that it can take a long time to get to sufficient cardiac stress with preload while doing these longer steady state intervals or just more of them. So like when I was starting out and I got these given to me, like five by five minutes with two and a half, five minute, 10 minute rest, whatever it was. I would barely feel the first two like breathing through my nose. The middle one kind of started getting hard. And the last one, I noticed myself starting to breathe hard, but really it's no big deal. And my coach was like, oh, you just got 25 minutes at VO2 max. I'm like, did I? I thought VO2 max was breathing harder than that. And so like I had a 280 watt FTP. and getting intervals assigned at like 330 watts. But what I found later, you know, training myself is that my intervals were actually, my five-minute intervals were at like 370 to 400 watts to really effectively train my VO2 max, which as someone with both low FTP relative to VO2 max and a large anaerobic capacity was actually a pretty standard VO2 max workout for me. And that's going max. On the other hand, If you have low FTP headroom or you're fatigued, then you can have a hard time holding on to power. In one way, that's good, since as you fatigue, your power is going to drop, but you can still be at or near 100% VO2 max and cardiac stress and preload as the power drops, as we saw in the sprint and hold versus steady state cover art that we mentioned before. Too excessive fatigue, you can actually be too tired to elicit high VO2 or high cardiac stress. If you are having trouble holding onto your intervals, it's bad because people get discouraged from not hitting their power targets, right? And so when, really, if you just kept pedaling and accepted not quite holding a power target, you'd be getting in good training anyway. You know, you feel like you're pushing hard and you're breathing hard, your heart rate's way up. And, you know, especially with the breathing, if you feel like you're a gasping fish on a boat, like, you're doing it right. You're pushing hard enough. And when you cannot get to that point anymore, now you're too tired to keep going. That's interesting because I feel like in Training and Racing with a Power Meter, Andy Coggin talks about how... You know, if you start to miss by, you miss your power target by a certain amount, you should pack it up and go home. Well, there are two authors on that book, I remind you. Yeah. And I know that Andy is somebody who shares my philosophy here on going max for VO2 max stuff. Okay. I think power targets can actually be okay in two conditions. So if you're relatively untrained, obviously they're going to be fine. Or you're going to have to do a lot of them, like 40 to 50 minutes. Honestly, it's unsustainable in the long run. And one or two of you out there, maybe 10 of you listeners, saw one of my Instagram stories, at Empirical Cycling, by the way, go give me a follow if you want, where I put up a VO2 max block for one of my athletes, an extremely advanced athlete, and everybody was going, how can somebody do that much work? And the answer is by following the principles that I'm laying out here. You know, normally you might see that many workouts in a week and go, that's impossible. And yet he crushed it. He did great. But if you're an athlete, by the way, who seems to respond to just about anything and you never really find yourself having a performance plateau, you just keep getting better and better and better. Well, everybody's jealous of you, by the way. But even so, I train these people too. I train people who seem to respond to everything. What I find is that by, you know, higher cadence with the VO2 max and going max, these two things alone, I find we can make more improvements in less time. Even people who think they've got a plateau, we can still find improvements and we can find them in less time and reduce overall fatigue. So now instead of taking like a whole race season to reach peak condition, which in a lot of my consults I've seen very frequently. And then you can keep making improvements after your season's over. You reach your peak fitness and then you can push a little bit beyond. I think that's a waste of time. So when we can get to peak fitness and build past that several times a year by really focusing on stress and really working in that recovery, I think it's really a lot better in the long run to kind of have this approach as opposed to the take forever to kind of build you up approach. I think that in general, if you think about it that way, you're actually going to get in more stimulus throughout the whole year as opposed to That is exactly 100% right. As opposed to not. I don't have a good As opposed to doing less work. As opposed to not doing it quite as effectively. I would say I should take that back. As opposed to doing the same amount of work and getting less stimulus out of it. the physiologic benefit of going max and not being beholden to a power target. So I like this approach because, first of all, you are guaranteed to spend more time at a higher percentage of VO2 max. And, this is the crucial part, preload. If you're going max, I usually don't assign more than 20 to 25 minutes of intervals. Sometimes 15 as well. Because doing 20 minutes of intervals... worth of work can add up to like 12 to 15 minutes of time at max preload. So I just looked at a totally random set of VO2s from someone in the last couple months, and they spent 15 minutes in their top three BPM, nice and steady. This is five by four minutes, max intervals, high cadence. And, you know, if it's only the super max preload that ends up inducing adaptation that we only find at really, really top heart rates with Good diastolic filling volume that we know we're getting from the high cadence, we might be seeing five to seven minutes of effective preload as opposed to maybe a handful of seconds or maybe up to a minute or two when doing less effective intervals. This is depressing. And we're going to go through some examples of what I find to be less effective intervals later on in this episode. And if you read the title of this episode, you know where this is going. Anyway, so remember this is not a hard start. You know, this is a start hard and keep going hard, no matter what the watts say. And, you know, don't like start hard, then go to a target power, you know, because, you know, the VO2 is going to drop if you don't keep it max. Yeah. You got to peg that perceived exertion, basically, right, to just like... Yeah, and so... Grueling. Oh, yeah. 11 out of 10. Yeah, pretty much. But, you know, it's not start with a full sprint. Don't do that. Yeah. You know, the pacing is kind of hard to get or it can be hard to get at first. But honestly, after like two intervals, you're going to nail it. I promise. So I generally advise people to start about 20 to 30% harder than you think you can hold the power for the duration. Maybe a bit more for the sprinters. But not with a balls-to-the-wall sprint. And, you know, do this per interval. So, you know, start 20% to 30% harder than you think you can hold just for that interval, and then shut your eyes and think of England. So, hang on, your power's gonna fade, your breathing's gonna max out, and at some point, you will be done. And your power's gonna fade through the intervals for the most part, unless you're really, really good. But that's okay. Because remember, power's not like to V2 that tightly. With this approach, it should take you one to maybe one and a half minutes to get up to about the right heart rate and obviously diastolic filling volume. And if you come off the throttle a little bit, then you're going to come away from what I think of the adaptive zone of preload, and that's obviously not as good, according to my philosophy here. So the max approach, though, requires careful consideration of your recovery, how many intervals you can do in a day, in a week, in a month. in a year? And these are questions that we will get to not this episode because that's another very large discussion about annual planning. My third tip is to shorten your recovery intervals. This is kind of like high-intensity training but only sort of. So let's talk about this. So shortening your recovery intervals means that you have less time to reset yourselves to a resting state. which means less clearing out of metabolic byproducts, not lactate, and stuff like that. But generally speaking, this is a better approach when you're not going to really go max. If you're just doing like steady state intervals, it's better to, you know, this is one of the better approaches because, you know, when you perform your next interval, you're going to have a little less anaerobic contribution, you know, whether you want to call it Reconstitution of W-prime or DFRC or anaerobic capacity or whatever. The downside of this is that you may not be able to get enough recovery time to pedal hard enough. We just talked about this briefly for a second. So you need to think about the balance between how hard you're going and your recovery interval. So what I usually advise my athletes to do is to start with shorter rests and then add more recovery time if you think you need it to go hard enough. for your next interval. And this is really just like a part of my coaching approach in general is, you know, especially when people understand what they're doing and what they're going for, then I find that, you know, with 90, 95% of the time, you know, everybody, 99% of the time, everybody's going to nail this. And if you want to think about this in like physiology 101 terms, you're not going to get past the EPOC, the excess post-exercise oxygen consumption. So you kind of start in a little bit of deficit. And this is kind of the way that the HIT intervals work, kind of, which was in one of our first episodes, by the way, talking about this before I decided, you know, to truly nerd out. All right, tip number four, assessing your intervals. Looking for a heart rate range after the fact and not during. And also, don't have a heart rate max number in mind. So the biggest number you've seen could easily have been on a hot day after no sleep and nine espresso shots and it's your fourth day of training. And if you see that heart rate again while you're in form, it's probably bad. So what I usually advise is to look for an approximate heart rate plateau. So if somebody's max on their intervals is like 185 to 187 BPM, I think I was actually looking at a workout for this, but they're going to start out with a rapid increase to like 179, 180, 181, 182 BPM before increasing gradually. And this is about how I look at knowing if we're in the right zone. The gradual increase doesn't really come into my thinking. It kind of does, but like I said before, we're not really sure where the diastolic filling volume is, where the max is, so we're just looking for max, right? And so I'm not looking for like 90%, and this is my training philosophy based obviously on the physiology. I want to create max diastolic filling volume for as much preload stretch as possible. Now, when you're doing intervals, This is feedback that I request from my athletes all the time. I say, pay attention to your breathing. So if I see something kind of funky with the heart rate, I say, you know, was your breathing maxed out on this interval? Your heart rate didn't get as high as I thought it might. And they say, yes. I go, all right, it's probably pretty good though. Probably a decent interval. Maybe not the best, but probably decent. So I say, pay attention to your breathing. So if it's for you or someone you're coaching, like I said before, if you're gasping like a fish in a boat, then you probably nailed it. And it's not comfortable. Yeah. And if you're out there and you are somebody who thinks that doing your intervals at like a blank percentage of VO2 max feels too easy, that's because it is. So go harder, pay attention to your breathing. Tip number five, change interval durations. Part of the athlete individualization aspect of training VO2max. So if you can't pedal long enough to match the interval lengths that you've given yourself, shorten them. If you can't pedal hard for like six, seven, eight minutes, don't pedal that hard for that long. I have athletes where this is the case. So I would say that two minutes is the shortest VO2max interval I would assign. Since it'll still take a minute, bit over a minute to get to the right O2 uptake and preload, so we just do more shorter intervals. On the other hand, if you seem to be able to pedal long enough and hard enough, keeping intervals longer, I think is the way to go. I have a few athletes where we keep intervals four minutes and over, and others where we keep it four minutes and under, and that's just a totally arbitrary spot, doesn't have to exactly divide up that way. But, you know, for some folks, Will also start long and get shorter as the fatigue of training V2 Max starts to increase. There's a lot of ways to do it and everybody needs something a little different and this is one of the things that I do with the athletes that I train. Obviously, extreme individualization. This is why I don't do any cookie cutter training plans because I don't know what you specifically need. I think that's a good point too. The five by five standard cookie cutter thing is like a Good place to start, but then, you know, you have to figure out what is a better or more, like, there's something to be said here for, like, workouts being accomplishable. Like, you know, if it's five by eight or something like that and you physically can't get through it, then, like, you're not getting anything out of the workout because you're not doing it. Yeah, 100%. Yeah, so, like, a five by five minute interval. You know, we could have done this episode, we could title it like, What's So Special About 5x5? 5x5 is like 2x20 for FTP. It's like a fine, middle-of-the-road VO2max workout. You know what? No matter how you do it, you can look at the factors kind of surrounding the effort, you know, according to, you know, the previous tips and stuff, and change interval lengths to make sure that someone is optimizing their time at max preload. So, for instance, one of my athletes... where we always keep the intervals under four minutes, usually like two to three and a half minutes. Longer than that, what I find is that he actually has trepidation about hammering that long. He's totally capable of doing it if he wants to. But every time he does a five minute interval or longer, his heart rate, and yes, with the high cadence, you know, we'll get maybe a total of what I assess as 90 seconds per interval really challenging his preload. For 20 minutes of work, 25 minutes of work, he'll get six minutes of interval time here, and to me that's not worth it. But if I look at a three and a half minute interval from him, he's got more than two minutes in the right area. Huh. So he'll only need to do three of these intervals to, you know, effectively have the same stimulus as four by five or five by five. I was going to say, why do more when you can do less time? Like, it's fun to brag about how many hours you slog away on the bike or whatever. But like, sometimes when you're real people with real lives, like, if you can get your workout done in an hour and 10 minutes instead of an hour and a half, like, that's kind of nice. Yeah, it's very nice. And, you know, the thing is with him, like, if we, you know, go for 20 minutes of work by three and a half minute intervals, you know, he's still going to be in that like 10 to you know 10 to 15 minutes of effective stimulus range as opposed to like you know doing 20 minutes of work intervals at 5 minutes where he still only gets like 6 minutes but this is why I don't use HIT high intensity interval type training to improve VO2max in already trained athletes we kind of addressed it in the HIT episode from way back in the day but you know I listened to it again and honestly I was pretty hand wavy I was not satisfied even when we were recording it with the explanation because honestly I didn't know how much detail to add in or especially how to effectively communicate it but I think I do now. So HIT training has several definitions by some doing like a five minute all-out interval constitutes this mode of training but what I'm really talking about here and I'm going to use HIT training to mean intermittent intervals. So like 15-15s, 40-20s, 30-15s, et cetera, et cetera, you know, in order to train VO2 max. Obviously there are other benefits to this type of training and don't get me wrong, I definitely assign this type of training to my athletes. Anybody will tell you I definitely do. But I never assign them to improve VO2 max unless someone is basically untrained and it's kind of fun. Kind of fun? Some people love these intervals. They really do. So we're going to talk about what I really use these intervals for in another episode. So most people trot out Ronstadt studies to say these intervals are effective for VO2max. So let's do the same. And I'm going to do my best. I'm being honest here. I'm going to do my best to try to put it in the best possible light. And after really digging into these studies, it's kind of hard from where I sit now to do that. So when I tell you why I think a lot of these studies are disingenuous or a gross misinterpretation of data at best or not understood by their authors at worst, you see exactly what I mean. And, you know, this is not to say that Ronstadt's not a smart person. There's definitely studies with the name Ronstadt on it that I really like and I think have great methodology and such. This is not one of them. I think the first time I saw an HIT study like the one we're going to talk about now, you know, I was honestly thrilled and I started implementing it with my athletes immediately with the intention of improving people's VO2 max until I really dug into them. And, you know, the one we're going to talk about, you know, today and the one, you know, from 2014, I think is, you know, about the same place. We're going to talk about the 2020 study called Superior Performance Improvements in Elite Cyclists Following Short Intervals vs. Effort-Matched Long Intervals Training. As in the introduction, the authors note that energy-matched intervals, quote, artificially constrains the training in a manner not representative of how athletes may perform their trainings in real life, unquote. Which I agree with, and that was one of my criticisms of, you know, of, um, any work-matched studies. All right, so the 2020 Ronstadt study took 18 male road and cross-country mountain bike cyclists from the national level, right? So a very high average VO2 max. And what they did was they did effort-matched 30 15s versus four-by-five-minute steady state, right? So RPE 17.5, that's the effort-matching. And we see a view to max increase in the 3015s and not in the 4x5 minute. We see more power at 4 millimole of blood lactate in the 3015 group, the HIT group. And we did not see any improvements in the steady state interval group. So on the surface, this looks great. Yeah. Let's start digging. The tests they did. Ramp test increased 25 watts per minute until fatigue. So who knows how long that took? Potentially too long. So this is our first source of potential error. And I reference you to the Vietimax ramp test episode that we did previously. They also did a 20-minute test at self-chosen cadence, and they had blood lactate measured every four minutes. Cool. Training protocol. The SIT and the LIT. So they did the short interval group, that's 30-15s, and the long interval group, that's four by five minutes. So long interval group did four by five minutes. two and a half minute recoveries. So total work time, 20 minutes, total recovery time, seven and a half minutes. The short interval group, the HIT group did 30 15s, 30 seconds on, 15 seconds off for three by nine and a half minutes with three minute recoveries for a total work time of 19 and a half minutes and 15 minutes of recovery time. So they've got double the recovery time. The distribution of training time and zone between these two groups during the test study. They were matched for before the test study, so that's fine. Lots of endurance training, kind of low intensity stuff. In the study, their low intensity zone is 60 to 82% of peak heart rate, middle intensity zone of 82 to 87% of peak heart rate, high intensity zone over 87% of peak heart rate. Stop right there. My first problem here is that this is not individualized at all, which is obviously a problem with a lot of studies. And sometimes doing the averaging works, and that's great. Sometimes we want to see individual results. We do see that in this study. But we're not individualizing for heart rate. And we know that for a lot of people, heart rates are a little different. So I looked at a random athlete who hits his max heart rate at about 190 BPM during a five-minute test. The same guy sustains 90% of that doing FTP work at 170 BPM. And I don't think FTP work really actually constitutes high-intensity training, right? So his last FTP test, 58 minutes at 172 BPM, right? I mean, it's hard work, but this actually to me is the first place where this study starts getting disingenuous. It's because this classification of heart rate ranges is not individualized, first of all, and second of all, you know, I don't know if they did this on purpose, how they set these zones, but it means that what somebody can actually be doing as threshold or sub-threshold, which we all know is a lot easier than going over threshold, can actually get misclassified as high-intensity training. and this is something that we're going to take a look at in just a minute when we look at the actual work rates. So the study's conclusion, the short interval group improved a bunch of stuff, long interval group did not. So let's look at table one of the study. Number of HIT sessions per week, number of training sessions, like both the long intervals, four by five minutes and the 30-15s. So they averaged 8.8, 8.9 sessions a week for the Short Intervals and Long Intervals. That's fine. Average RPE, 17.6 out of 20 on the Borg scale. I don't know why they can't just use 1 to 10 like everybody else. All right, so the mean, the average power of the SIT, the short intervals, was 441 watts for the work intervals. That's just for the 30 seconds on. Long interval training group, they averaged 338 watts. Alright, so, not so bad, so obviously you go, you know, you go harder intermittently, you're going to be able to work harder, you get a little bit of rest, that makes sense. If anyone has done 30-30s, 20-40s, whatever, you'll probably notice that, like, you hit pretty high averages for those work animals. Yeah, definitely, because you get a little time to recover to, you know, hammer anaerobically, or whatever it is. However you want to explain it. These actually work out to, for the, For the 3015s, they work out to 94% plus or minus 3 of the W max, the highest value of the ramp test. But the 4x5 minutes works out to 79 plus or minus 7% for the 4x5 group. Right? So let's think about this for a second. In elite cyclists, if we take the ramp test at face value, Since we don't actually know the VO2 in liters per minute for FTP, Maximal Lactate Steady State, whatever you want to call it. So these athletes were working at 72% of VO2 max on average for elite cyclists. It's very safe to say this is under threshold. Are you kidding me? No, but it's effort matched. Nobody trains like this. Nobody does FTP work or under FTP work and goes, I'm working on my VO2 max today. I wonder too if like the subjects while they're doing this are like, this isn't hard. Well, see, it's effort matched, you see? Yeah. So the group that was working over threshold seemed to increase their VO2 max and in fact did. It's not surprising. Yeah, where the other group did not. No shit! So the change in the short interval group, the 3015s, for VO2, it increased by 0.13 liters per minute. The other group saw an average change of 0.05 liters per minute, or a little less than half of that. 3015 group, the change was statistically significant, and the other group, it was not. So the standard deviation of the first group... was 0.3 liters a minute. The second group was 0.5 liters a minute. And this, you know, these standard deviations affect the statistical analysis. And, you know, the effect size of magnitude of improvement was, you know, 0.2 for the 3015s, right? No kidding. Yeah. All right. Let's look at the 20-minute... Power and the Power Output at Blood Lactate of 4 millimole. All right. So obviously this is something else that bugs me, the lactate thing. But- Why don't you tell us how you really feel? I will in a second. Before the intervention, the groups had been doing a couple weeks of low-intensity training, as we mentioned. This is enough in itself to shift the short-term adaptations in substrate metabolism and buffering capacity and things like that. So when you're working intermittently, Over Threshold versus working just below it. So that's what the 3015s and the 4x5s were doing. The 3015s, you not only develop the ability to like buffer acidity and maintain a higher anaerobic work rate, you're kind of training that a little bit, you know, but you're also training larger motor units. And when you're working at like FTP-ish, let's just call it FTP to be generous. 4x5 minutes is not long enough to like do anything. So I would expect basically no increased motor unit recruitment. So when you go do your 20-minute test, you're in the same spot that you were before. But the 3015 group, you know, they were accessing these larger motor units and they had a little better training there. And so this could, you know, explain not only the VO2 max increase through an increased AVO2 difference, you know, especially if... the larger motor units are a little more aerobically trained, right? The 20-minute test result also, so the actual average in the 3015 group went from 343 to 358 watts, just about no change in the other group. So, okay, first of all, you know, you're not at VO2 max for this whole test, right? So a 0.1 liter per minute improvement in your VO2 Max or 0.13, let's call it 0.15, is not going to explain a 15-watt difference in 20-minute time trial time or time trial watts. At best, if we assume that they're at VO2 Max and they're making 62 watts per liter of O2, meaning a 0.1 liters per minute increase is 6 watts, where's the other 9 watts from? Their 20-minute time trial went up 15 watts. Where are the other watts from? Hmm, where else could they? Interoperative capacity! Yeah. So, this can partly explain the increase in Wmax, I mean, the interoperative capacity increase. You know, interoperative capacity, W-prime, FRC, whatever you want to call it. Look at Wattstock number 18, where we discuss rank test protocols. But, it also makes sense for the 20-minute time trial. And this is why, you know, with the 20-minute test, you can, quote-unquote, teach to the test. You can do a bunch of anaerobic work and see improvements in your 20-minute test immediately. And it's not long-term actual aerobic improvements. It's polish. And now let's look at power at 4 millimole. So when we do things like over-under intervals, we produce a good amount of lactate. And lactate does indeed seem to induce some genetic changes. I mean, well, it better. The body needs to use what's around for fuel, and lactate is a good fuel. It's a half-combusted carbohydrate, right? So we need to develop the ability to use the lactate as a fuel in our muscles, and obviously in the rest of our body too, like heart and blah, blah, blah. So what happened here is that probably at the same power output, more lactate is being utilized by the 3015 group, but it doesn't say anything about your threshold or anything like that. It just means that at the same work rate, you are using more lactate, so the value in your actual blood is lower. Doesn't mean anything else other than that. That's the only thing that we can for sure say about that. So the other source of error on power output at 4 millimole is blood volume. Obviously, it was not measured in this study. That would be great, but they didn't. So this is... also another likely candidate to be the source for VO2 max improvements, right? So having more blood volume means, you know, you're going to have more preload in the heart like we saw in the COIL study where giving somebody a little more blood volume when they do, it will give them some extra VO2 max. And this is something that happens with high-intensity training is, you know, you're You know, your blood pressure is going to lower and lower and lower, and this is going to induce a larger increase in blood volume. This is actually one of the things that FTP can help you a little bit with VO2 max, is not only you'll, you know, improve your muscular ability to increase your AVO2 difference, but you are also going to be working for a long time at a somewhat low blood pressure. and, you know, you're going to build a little bit more until your body is like, oh, okay, we need a little bit more and this is going to increase your view to max. More blood volume, this is the other thing about the blood volume, so more blood volume means the same absolute amount of lactate produced is more dilute. And remember that blood lactate is measured in millimolar or millimoles per liter. So if you increase the denominator, you're going to see the actual number go down, right? I think one thing to point out in all these things is some of these things are not necessarily bad. Like this adaptation to using lactate as fuel is a good benefit. Like that is a positive adaptation that your body is making to these high intensity intervals. And, you know, that's... But that's not what the study was looking at, but that is something that the study sort of confirms. Yeah, and, you know, looking at, to me, looking at blood lactate values like this is another exercise physiology 101 type analysis. Like, we can go so much deeper and we're not. It's kind of suggested in the intro of this paper that this is comparing the way that athletes actually train, but it's really not. If it were, the 4x5 would have been harder intervals. But these are straw man intervals. They're like a fluffy, comfortable version of an interval, you know, that's easy to knock down. You know, it's there, it's a sham. It looks okay enough to scare off a lot of people from further analysis and digging deeper, but, you know, this study does not, in any way at all, in any universe, prove that 3015s are superior. What we're trying to say is that the study, while it had Good Intentions. It wants to do good things. You want to look at how people actually train, what are very common types of intervals, and see what is better method A or method B. It's an admirable goal, and I think that's a positive study premise. But I think, as you've pointed out, there were several flaws in the methodology, and not the least of which is the way they set up the two training protocols for the two different groups of subjects. You could repeat this study or attempt to improve upon this study by addressing several of these things. And that might be interesting. That might actually be a very worthwhile activity. This study on its own isn't like the nail in the coffin of, you know, five by five minute intervals for VO2 max training. No, not at all. And this is actually one of the problems that with Effort Matched, you know, this study, started out by talking about, you know, the work-matched approach is probably not the best, so we're going to go for effort-matched, right? And so the, so what everybody I've argued with this about says is that, you know, if we can get more improvements in VO2 max from doing 30-15s as opposed to 4x5s, and it feels the same to the athlete, then I'd rather do that. And my answer is, like, What I'm trying to say, like, the effort matching was a source of error. The same way that, you know, witnesses in court cases can be unreliable. Your memory can be unreliable. You know, the worst thing that you've experienced and the worst thing somebody else has experienced can be vastly different. But to you, they're still both the 17 out of 20 in the badness of experience. Yeah, I think that's a good point. Like, there is some, just like with anything else, there is some tuning and some training in using RPE for exercise, just like anything else. Someone who's brand new probably thinks a 15 out of 20 is way different than someone who's a seasoned veteran. Oh, yeah, definitely. Now that we're standing here in the ruins of the Ronstadt study, what are we left with? Pedal harder. Pedal harder. There's a little bit of that. Well, my reasoning here, intermittent intervals don't present enough time. at high enough preload to cause adaptations in the well-trained. All right, so now this is our discussion section on the Ronstadt study. It may work for sports that have a large amount of preload already, like cross-country skiing, where we may have some wiggle room in what we might call adaptive preload intensities, as we kind of discussed this in the last episode with a little bit of comparative physiology between sports. And this, by the way, is exactly what we were talking about in the HIT episode when we said that the Tabata style, intermittent maximal or, you know, very high over VO2 max kind of thing, or the submaximal training versus, you know, that, as they did in the Tabata study, you know, it doesn't target the true limits of physiology in well-trained individuals. So in that episode, we talked about ranodyne receptor fragmentation, calcium leak, leading to aerobic adaptation. and people who are untrained. But it doesn't happen in the trained. Calcium leak, by the way, can be seen by the muscle as, hey, we're still contracting, keep adapting. But it doesn't happen in trained people. So that's not what's happening in the Ronstadt paper here. So if I look at two sets of intervals by the same athlete, so same guy doing three by eight minutes of HIT work, so 30-second work intervals versus a four by five minute VO2 max workout, right? For each 30-second work interval during the HIT work, he was going max for every one of these, by the way. So 100% all out every 30 seconds. He only got about 10 to 15 seconds at what I would call maximal adaptable heart rate if we just pretend that he was at max diastolic filling volume, right? And let's put these intervals in the best Cardiac Adaptation Light as possible. So let's say for 15 seconds for every 30 seconds of work, we're going to provide him a maximum cardiac stimulus for eccentric hypertrophy. But if we look at four by five minutes of VO2 max work the way I assign the intervals, I'm actually going to nix the first interval. I'm going to completely discount it because he actually was having some trepidation about going that hard, but he nailed it on the second, third, and fourth intervals of five minutes. So now we've got three by eight minutes. We've got 24 minutes of HIT work versus three by five minutes of actual VO2 max work. You said four by five or three by five? Well, three by five because we're not counting the first one. Oh, sorry. Yeah, yeah, sorry. So we're nixing that first one. So we've now got intervals just two, three, and four that we're looking at. So 15 minutes here. So he got... 10 minutes at his highest heart rate values at high cadence, right? So he actually just went straight to max and it just stayed there, plateaued. And he was doing high cadence, so we know he's got high preload. So we know he's got 10 minutes out of those last three intervals where I'm sure he's generating really good... Cardiac Stimulus for eccentric hypertrophy to increase his very long-term VO2 max. Because as we've established in the last five episodes, it's stroke volume. That's it. So HIT intervals, his 30-second work intervals, we have eight of them times 15 seconds for each 30-second work interval times three, which means six minutes of cardiac adaptive stress. At the most. Yeah, and that's being generous. Also, let's look at work rate if we want to do work matched. So, steady intervals were at 100 kilojoules each. And these are in relatively small motor units. Average pedal force for these is around 200 newtons. And, you know, we can expect them to be getting into some larger motor units with the fatigue. That's fine. The HIT intervals cost 150 kilojoules for eight minutes. Much more. Yeah, so the five-minute expenditure in these was actually comparable to the regular VO2s, a little over 100 kilojoules. But much higher pedal force. So he's using much larger motor units, which, we haven't discussed this on the podcast, I don't think, take a longer time to recover than smaller motor units. Because smaller motor units, you use them when you're walking around. You use them just pedaling around. These are really well-trained. Larger motor units are less well-trained. They get access less. They have less training stimulus in them. So the average pedal force for the HIT intervals started around 500 newtons for each work interval and faded to 200 newtons. So the entire work interval is over the same, it's over the force, the average force for the VO2max intervals. And so what this really means is that We have to hammer harder on larger motor units and spend more energy on longer intervals to get as much eccentric hypertrophic stress on the heart. Interesting. So back to this sort of efficiency argument about using up your kilojoules in a smart way and also making sure that you're doing work that's actually... going to give you the stimulus that you want as opposed to burning these extra 50 kilojoules per bout, if you will. Yeah, and he had those intervals assigned for not VO2 max work. That was not what we were working on in that. Anyway, but we should actually go to the original Tabata study that compared high-intensity work against one hour at 70% VO2 max. Yeah. An hour! Sorry. Just solid sweet spot tempo workout. Yeah! Sweet spot to FTP work, depending on the athlete. Might be tempo, we'll see, but we're gonna call it sweet spot kind of FTP work. And what they found was that the Tabata intervals, anaerobic capacity went up 28%, and VO2 max went up 7 plus or minus 1. Milliliters per minute per kilogram. And the people who were not highly endurance trained, right? These are team sports athletes for the most part, one swimmer, probably short distance. And there was no anaerobic capacity improvement in the 70% VO2 max group, but VO2 max went up nearly the same amount, five plus or minus three as opposed to seven plus or minus one. So there's a wider spread of responses. You know, like we said, these are not endurance trained people. These are not highly trained endurance athletes. So VO2 max, now that we know more about it, now that we spent five hours leading up to all this, well, six now, we know that VO2 max could be increasing from any number of mechanisms. But the most likely candidate is plasma volume and blood volume. And in another episode, one day, we're going to look at how this gets regulated and talk a lot about kidneys because I love kidney function. It's mostly going to be for me because I love kidney function, but hopefully you all get something out of that. So also in the HIT episode, we looked at the Tabata study plus another study where folks did 3x20 minutes at FTP, actually FTP, versus HIIT intervals. And what they looked at was ultimate gene expression, but not impact on system physiology. And so they didn't say, you know, these intervals increased their VO2 max by this, whatever. They were looking at genetic expression and they found very similar levels of genetic expression saying, you know, we might be able to, you know, do something with this in terms of whole muscle genetic expression, physiology. That's cool. I genuinely do think that's cool. And Ronstadt had people doing 30 15s versus four by five minutes at 70% VO2 max. These are seriously straw man intervals. They're just built up to be knocked down. They're an absolute sham. And, you know, other studies that compare these two things, you know, I like those other two studies. I like the Tabata study. I like the study with HIT versus 3x20 FTP. Those are good studies. Those are things we should be talking about. We should not be talking about this Ronstadt paper. You know, comparing this Ronstadt paper to the Tabata study. Tabata really gave the endurance training stuff a really good shake. An hour at 70% feed to max. You know, 3x20 at FTP. Now that is a good training protocol. That is two apples to apples or like, you know, apples to pears comparison. What Ronstadt has done is taken an apple and compared it to a ball of cotton. So I've had people do some of these protocols, honestly, with the intention of them improving feed to max. This was a while ago now, but looking at those power and heart rate values, they really only get you to like 90% of max heart rate for some well-trained athletes and not for that much time either. And in the end, these intervals improve these athletes' anaerobic capacity and not their V2 max by any stretch of the imagination. In terms of adaptation, If we could just assume diastolic filling volume goes hand in hand with heart rate and power and VO2 or whatever, but we also cannot be, but the thing is we still cannot be sure if we will get enough preload adaptation for eccentric hypertrophy because we can't be sure what amount of max preload volume is enough to get adaptation. If you're plateaued aerobically, I'm certain that you need to work your stroke volume harder, right? And assuming that people are on a spectrum for stimulus and adaptation, which obviously they are, the thing is I want to work with the strategy that is going to get me as much adaptation, as much as possible with as, you know, I want to be sure that we're going to adapt. That's what I'm saying. I want to be absolutely certain that the intervals I assign are going to lead to somebody getting fitter in some way or another. I think another thing is that you kind of think of it as if you're working on these adaptations and knowing that with the knowledge that things like plasma volume are rapid adaptations that appear quickly but then also kind of plateau in their usefulness whereas working on actual heart rate physiology for lack of a better term is like a much more long-term beneficial useful What am I trying to say? You're like, you're spending your time trying to promote a component of physiology that will better enable more, better training in the future. Like, if you just focus on plasma volume as an example, we saw that that usefulness tapers off in, after you reach the Point that you're no longer considered untrained or recreationally active or whatever you want to put it. Whereas, you know, working on these heart muscle adaptations help enable future good training, quality training. Yeah, exactly. And this is actually one of the reasons that, you know, early in this episode, I called VO2 Max, just regular VO2, you know, kind of a blunt instrument, like a very crude measurement. Because we want to know what's going on under the hood of that measurement. We want to know, you know, what's going on deeper in the physiology. And, you know, this is my opinion, very much my opinion. But if somebody pays me to make them faster, and we go through like a month, maybe two, of trying to improve you to max, and, you know, we don't see any adaptation. All right, cool. That was how many hours, how many kilojoules, and no result because we learned that you actually have to work harder? And now you're going to do intervals that we could have just done in the first place? I'm not about that. I'm not. You know, we go right to the heart of the matter. That was not an intended pun. That's a good one, though. Whatever is going to induce max adaptation? or what we're sure is going to induce adaptation that you could possibly accomplish and recover from, that is my first choice. But, you know, this actually brings into light kind of short and long-term training strategies because a lot of people look at the Fick equation and they think that, you know, peripheral adaptations might lead to a big VO2 max improvement, but, you know, goes up quickly to a certain point and then it plateaus. And this is the kind of thing that takes years to accomplish with tons of high-quality training. And this is where my, you know, all training is base training thesis applies. Because, you know, we saw in the AvO2 difference study that, you know, really through all these last episodes, is that peripheral adaptations are not a big factor in long-term VO2 max improvements. It's obviously heart stroke volume. You know, even... like a 5% increase or a 10% increase in AVO2 difference is not going to make nearly as much of a dent in your V2 max improvements as increasing your heart stroke volume but you know with this short and long-term interplay though with like blood volume like it that might be why going from endurance to intensity may be a good long-term training strategy because threshold and sub-threshold all the way down to like just puttering around kind of, you know what I mean. That will increase your blood volume, your muscle capillarity, your vascular capacity for blood volume. And this in itself can increase VO2 max and stroke volume, as we saw in the COIL study. And, you know, usually then a performance plateau means it's time to go straight for heart stroke volume. But as you go through training, you know, it won't last forever. That's what we really get when, you know, you're kind of aerobically tapped out. And this is why, like, forever base training doesn't work. You know, somebody's like, I'm going to ride, you know, 30 hours a week all year. Maybe I'll take off the holidays. That's why this kind of training, you know, on paper it says endurance training will increase VAT to max. FTP training will increase VAT to max. But it doesn't work forever because you never eccentrically stress your heart. Enough by doing that intensity. And, you know, as we saw in the AVO2 difference episode, like a 10% improvement in utilization, you know, maybe into like the low 90% range is nothing compared to long-term potential of increasing heart stroke volume. It is a factor if you're one of the best in the world and you need to get that last half a percent, both out of your AVO2 difference and your stroke volume. Yeah, absolutely. Then when I, you know, when I do consults for people at that level, it's very much part of the discussion. But for average athletes, stroke volume is the really big thing. And for developing athletes, too. So when you hear people talking about, you know, keeping up someone's volume to keep their view to max up, what they're really talking about is maintaining their vascular capacitance and blood volume, most of all. And that's what's going to maintain their heart stroke volume because of the Frank Starling Law. This kind of circles back a little bit to your idea that cookie cutter training plans aren't the best because depending on where you are and depending on what your goals are and how your training history, you may have to do a different type of intervals than the other person and that's fine. That's totally fine. There's no silver bullets like we said before. And if working with somebody who we're absolutely sure has maxed out their stroke volume and all sorts of whatever else, You know, the training strategy shifts for the long term. And, you know, I've actually had some athletes come to me who, you know, do like long endurance rides all the time. And, you know, they think that they're tapped out on their like FTP and their VO2 max, like, oh, maybe I can gain five or 10 watts. They figured, oh, I'm riding, you know, 20, 30 hours a week all the time. I'm tapped out. That's not the case at all. And what about the people who seem to adapt to anything? I mean, I've definitely worked with these athletes too. It's obviously still working with a lot of them. And this approach that I have here of going straight for preload adaptations, I still think is the right development strategy, even if you seem to respond to anything, as opposed to doing the typical three to five minute steady power intervals, because you're, you know, like we talked about, you're going to get fitter faster and you're going to be able to go past your previous levels of fitness. and you're going to have a nice up and down through the season. Do you have any other thoughts before we wrap this up? No, I think we covered it and hopefully I think people can see now the connection between what VO2, VO2 max is physiologically and what kind of exercises actually improve those qualities as opposed to just thinking, ah. 5x5, uh, like, gonna go do 5x5 again, gonna find a 5-minute hill, gonna, you know, et cetera, et cetera, et cetera. Yeah, and again, I mean, I'm putting this out there because, you know, this is what I find works the best, and if you don't agree with me, honestly, I think that's fine. My last thought here, I guess, is that one of my big issues in a lot of exercise physiology, obviously not everything, but... is the fact that everybody's looking at one number, FTP, VO2 max, later per minute, whatever it is. These are phenomena that emerge from complex underlying intertwined systems. And without looking at the underlying physiology, the system's physiology, or assessing the impact of a certain type of training on the various components of the physiology, hopefully people now understand a little bit more about what VO2max is and why certain types of VO2max training may be more effective than others and hopefully people actually now feel empowered to go out and try some of these things too like try working on you know a different style of VO2max training than you've done in the past and you can probably see for yourself if your power in that sort of traditional sort of 3 to 8 minutes goes up after doing new type of intervals. Or maybe he doesn't. Or maybe he doesn't. And he tries something else. And that's what this is all about, really. All right. So I hope everybody enjoyed these last couple episodes and we have one more to go on V2Max that is your questions so send your questions to empiricalcycling at gmail.com if you have any coaching inquiries we would be happy to help you work on your V2Max and whatever else you've got going on so again thank you for listening everybody as always and please subscribe to the podcast and share it with a friend especially if you have a friend who may need some help in their V2Max training And so if you want to support the podcast, you can make a donation at empiricalcycling.com slash donate. We have the show notes up on the website for all of these studies referenced and the previous studies referenced are up in the previous episode notes. And for coaching and consultation, inquiries, and questions or comments, you can send an email to empiricalcycling at gmail.com. So thanks, everybody. We'll see you next episode. Thanks, everyone.