Welcome to the Empirical Cycling Podcast. I'm your host, Kolie Moore, joined as always by my co-host, Kyle Helson, and I want to thank everybody for listening. So please subscribe if you have not and head up to iTunes and give us a rating if you're enjoying the podcast and the stuff that we have here. And if you're enjoying the podcast enough to send us a donation to support the podcast, you can do so at empiricalcycling.com slash donate. We've got the show notes for the episode today on the website. And for all coaching and consultation inquiries, questions, and comments, you can send an email to empiricalcyclingatgmail.com. And so, of course, if you are looking for a coach, we are taking on athletes now. I normally don't plug this hard at the start of an episode, but if you're looking for a coach for 2020, now is a good time to start training. So shoot me an email. And if you want any Empirical Cycling Podcast swag, you can head to empiricalcyclingpodcast.threadless.com and you can get bottles. Shirts, and Hats, and Stickers, and Skateboards, and what else do they have, Kyle? Shower curtains, bath mats, pillows, rugs. And also, I want to do a listener question episode. And this episode is going to be on FTP training. So ask your FTP training questions. So what I'm going to do is I'm going to post a thread on r slash velo. and in there ask your question and Kyle and I are going to go through the questions. We're not going to answer them on Reddit. We usually do but we're going to hold back this time or you can also email me at empiricalcycling at gmail.com. So before we dive into the stuff that we're going to get to today As alluded to in the last 10-minute tips episode on, you know, do you know if your intervals are doing what you think they do? Today we're going to take a deep dive into what makes training so complex. And we kind of touched on it in the last FTP episode, but not really. It was there, but I didn't want to quite get into it. And so today we're going to look at something that's as simple and basic as you can get with cycling, the endurance ride. Hopefully by the end of the episode you are going to understand a little bit better just how complex it gets when we look at these rides past the standard lab tests, past the standard assignments of some zones and thresholds and the one-dimensional kind of science and textbook kind of things that are in your Exercise Phys 101 class. And so, you know, during exercise, it's rare that things actually stay in a steady state, even if we hold power or heart rate steady. Because things like heart rate and body temperature, lactate flux, you know, active muscle mass, you know, muscle acidity, enzyme regulation, all this kind of stuff, you know, these are just the first things that come to mind, all this kind of stuff, none of it... has a one-to-one relationship with anything else through time. Because we are in an endurance sport, we're not in a snapshot sport. So if we take a snapshot, things are nice and clean and neat. But if we think about things in a more complete manner, we think about what we're actually doing over time, things get a lot more complex. And so it's given this context that I want to talk about whether we should pace our endurance rides by power or by heart rate. Because this is a question that I've seen asked a lot. Over the years, and I've seen it several times in the last week or two, so I thought this would be a really good episode to do, because in my opinion, I have not seen this answered as fully as I think it deserves, because when you understand how the body changes over time, this will give us excellent insight as to how we should pace our endurance rides. So with regard to that, Kyle, tell us a little bit about some impressions of endurance training. So I think a lot of people who have been around cycling at least a little bit, and I keep always, I think I've mentioned this example now numerous times in the podcast, but the classic old school, old curmudgeon-y way of describing Endurance and base training to someone is that you need to ride in the little ring and just pedal around at zone two endurance miles, like big long rides, like the whole winter. People say things like, oh, you have to go slow to go fast. And so usually when people introduce you to the idea of intervals, they tell you that, oh, you have to build this big aerobic base doing these long slow rides in the little ring in the winter. and then in the spring and more the summer when you're racing they say you can move on to doing intervals and intervals like classic things like 2x20 or 5x5 or something like that but a lot of the old school wisdom is that you have to do these long slow endurance base miles to build up this base or this fitness level that will let you do these harder intervals later on. so it's to like prepare you for yeah I think the idea yeah people maybe is it Friel's book I forget there's definitely a book there somewhere there that has that's some crappy drawing of like a pyramid of like oh you're gonna build this like base and all the wider that you build the base like the taller you can build the pyramid which I you know anyone who's seen like The Washington Monument. That's like, you know, not a good analogy all the time. But, you know, but the idea is there that, oh, the more time you spend building this foundation of a lot of volume of riding that enables future higher intensity, faster riding. So the question that we're really faced here with is, you know, now that we have, you know, beyond the old school training methods, we've got like heart rate training, we've got power training. Is there any wisdom to the old school methods when we have these new metrics to ride to and we understand their connection to physiology a lot better? Because, you know, back in the day, they didn't have heart rate monitors. Like, all they had was just their bikes and the terrain. So, okay, so the next question is really, like, what does aerobic training do? Anyway, why do we need it? Like, what do we do these endurance rides for? And maybe that's going to give us some context as to the main question of the day is how should we pace our endurance rides? Like, based on, you know, the connection to physiology, based on the heart rate, what we know about that, and power data. Okay, so if we look at the chart that's in training and racing with a power meter on the adaptations to riding in each particular zone, What we actually see is that zones one through five, you know, recovery through VO2 max all work approximately the same things. I mean, aerobic is aerobic. Yeah. They may work... Some aspects of those little boxes that they've ticked more, slightly more, slightly less than others. But yeah, all the same boxes are checked. Yeah. And depending on your training status. Like if you're brand new, like lifting weights is going to improve your Fiat 2 Max. Right. Yeah. That's why I've said all aerobic training is base training because it all is going to help you. And, you know, eventually it all matters. And the rides that we're going to be talking about today are usually called base rides. But to me, I just prefer to think about them as endurance rides. So why do we do endurance rides anyway? Endurance rides to me are a good way to get in low intensity aerobic stress. So we can do a lot more easy and moderate pace riding than high intensity intervals. So, you know, if you have the time. That's a big if. Increasing the volume of the riding is going to lead to large benefits because you can only add so many intervals to your day before you really need to recover and adding more intervals on top of already hard work can be like impossible and or lead to overtraining and that's something that we definitely want to avoid. Yeah. Should We Program Endurance Rides For? Let's focus for now on how do we pace them and why. So the first method, the typical method that I see suggested, I've heard it on podcasts, I've heard a lot of coaches talk about it, I've heard some exercise physiologists talk about it, I've certainly heard Seiler talk about this kind of thing. You know, he said on some ride, I think it was on Twitter, he was going to... He did this ride by heart rate to make sure he's quote unquote staying aerobic. Well, let's assess that validity shortly. So there's a couple definitions of what endurance pace heart rate is. With Friel, in the Cyclist Training Bible, he suggests it's 82 to 88% of your threshold or FTP heart rate. Coggins suggests 69 to 83%, so like no overlap basically of your heart rate at FTP. Siler suggests it's below your first lactate threshold or the intensity at which blood lactate begins to rise above baseline. So I found a study on trained cyclists suggesting that it's 84 plus or minus 4% of heart rate max, not threshold heart rate. because a lot of studies don't really think about threshold heart rate. They think about max. There's a big disparity between the Friel and Cog in heart rate zones and the one that lines up best with it is the LT1 heart rate zone for polarized training. So the only issue with that is that Siler's suggestion of staying below LT1 for endurance training is actually, it's hard to find LT1. There's not like a fingerprint, quote unquote, anywhere in our heart rate or power data to say this is your LT1. But this is the one that has probably the most basis in actual physiology. But, you know, the four beats per minute standard deviation is pretty wide, so it's definitely not the same for everyone. If it was like one BPM, it would be like, yeah, it's the same for everybody, but clearly that's not the case. Yeah, four is pretty big. Not to mention just determining your max heart rate. Can be difficult. Yeah. If not. And it can vary day to day. Extremely difficult. Yeah. And that's actually one of the things that we're going to get to in a little bit. And we're going to talk about in depth in more episodes. Okay. So the other way to pace endurance rides is pacing them by power. So this comes from the philosophy of time and zone X equals adaptation Y. So this is something I touched on in the 10 minute tips episode. But not only the time and zone X equals adaptation Y, but also time and zone X. Equals Physiologic Steady State Y or Z, I guess. Coggin suggests 56 to 75% of FTP. And Friel in his Power Meter Training Book actually suggests the same as Coggin. And of course, Seiler would be suggesting power around or just below LT1 first lactate threshold. So training rides here typically, as Friel suggests, I think it's 90 minutes or two hours is sort of like the lower bounds of an effective duration for an endurance ride. We'll talk about that in another episode. Sorry to kick the cat down that road, but this episode would otherwise be five hours. So training rides here typically, you know, mid to upper quote unquote zone two. or your endurance pace. And so my educated guess here is that Coggin set this endurance zone because it is very likely for most people that it is under LT1. I have no proof of this, but that's how I would have done it if I had lactate data. And I think one thing to kind of get... in about the power philosophy is usually power is often touted as being a better metric than heart rate because people realize that heart rate can vary from day to day, which I'm sure people who've looked at their own heart rate data are familiar with. And so this philosophy is that if we ride at the same power, then we can't either let ourselves cheat or that it makes up for this sort of lesser accurate metric of heart rate. And, oh, if you're riding in this power, then this is definitely the sign that you're doing good work or you're doing the correct work or something like that on a given day. Well, let's first talk about how power and heart rate interact because, as you've said, people will notice that their heart rate is different. you know doing like the same ride basically on different days because heart rate can be affected by a lot of stuff however there are certain patterns in the heart rate that stick out and you know at this year alone I've seen hundreds of endurance rides from my athletes and you know like there are definite patterns and you know once we pull out to this bird's-eye view and we look at the patterns and we think about these To me, this is one of the most powerful things that we can do when we are looking at data. So let's get right into it. So let's take an example from one of my athletes. He did a six-hour endurance ride. He did 217 watts normalized power, 203 watts average. So very, very steady ride. It was a really good ride. So his heart rate average in the first hour was 132 beats per minute. He did 203 watts average. So in the last hour of a six-hour ride, he did 148 BPM and 197 watts average. So he lost barely any power, probably being within the margin of error of the power meter. And he definitely gained, you know, what is that, 16 BPM over six hours? So this is probably not new to a lot of people, but if it is, this is called decoupling. So this is how much your heart rate drifts compared to power. And so his heart rate drift was actually 13% over the course of the ride. So let's look at what's different between the two approaches when we think about heart rate drift. Power is going to decrease through the ride, and over time the power is going to come up to better match heart rate, but it won't always, and especially over very long rides. Though, for pros, and you know, I've definitely got a couple athletes like this where, you know, they can ride for like six to eight hours and their heart rate is not going to budge. Okay, so the theory behind, you know, riding to heart rate... The idea behind this is that, you know, this comes from, well, this comes from heart rate zones, right? So historically established by ramp tests. So you look at your first big inflection points and blood lactate points over baseline and, you know, that's your LT1 and your heart rate at this inflection point and your lactate is your, you know, lower bound of heart rate. But it changes over the course of a ride, right? And so if you subscribe to this philosophy, what's happening through the ride is actually you are increasing your training zone. So it might start as an endurance ride, turn into a tempo ride, and then maybe even a threshold ride by the end. So it can actually be infuriating if you're trying to figure out, do I do power? Because, you know, do I stay in the power zone? Do I do heart rate? Do I stay in the heart rate zone? Like, which one do I do? Do I split difference? Yeah. So now we need to think about why heart rate decouples like this. Now there are a lot of potential reasons why it happens, but we're going to look at one of the biggest ones. And this is the size principle added again. The size principle! Who doesn't love the size principle? Just the name of it makes me excited. Well, the name of it makes me excited too, and if you've listened to the podcast before, and you've heard the other Wattstock episodes that we've... brought up the size principle at least once, if not twice. So briefly, the size principle is that muscles are organized into motor units. So a nerve or a motor neuron connects to a bunch of muscle fibers. And this nerve plus muscle fibers is called a motor unit. That's the nerve and the muscle fibers together. That is a motor unit. And they turn on... or contract rather all at once, 100% all or none. And it's only those muscle fibers that are connected to that neuron that contract. So this is how we actually get gradations in force produced by muscles. So not every muscle fiber contracts when you move your muscle. Chemically, that would be very hard to do to get gradations in force by flexing all of your muscles' fibers at once. Alright, so when you start riding at endurance pace, everything's fine, for a while. Then, when the motor units that you're using start to get tired, you begin to use the next larger motor units, because they're fresh, they've got lots of glycogen, they're ready to go. And all you have to do is send a little stronger signal, and I've seen the studies, the electrical signal to the muscles gets stronger. So what's happening is, Larger motor units are typically composed of less slow twitch and more fast twitch fibers. So it's, of course, a gradation of fibers. It's not like this is slow twitch and this is fast twitch. And not every motor unit is fast or slow. So, you know, generally, well, refer to Wattstock number 12 for a lot more info on that. So fast twitch muscle fibers are less efficient than slow twitch muscle fibers. So I'm going to keep using the fast versus slow terminology for convenience only, although we know it's more complicated than that because we all listen to Wattstock number 12. So let's talk about efficiency. So efficiency is a measure of energy in versus energy out. I mean, Kyle, does the definition get any simpler than that? Probably not. I think that's the measure of efficiency in almost any terms, not just energy. But yes. Okay, cool. So what we're measuring is how much O2 are we inhaling compared to the energy actually in that oxygen versus the meager amount that we actually get to the pedals times 100%. Efficiency, by the way, is not economy. Though the terms can be confused, and I've seen papers where they are used interchangeably, which is infuriating. Runners deal with economy a lot more. In cycling, we don't so much. So we're going to just, if you start looking at papers about this kind of thing, just know that, and even articles, and don't get me started on the articles, so that these two words can be switched up by Unwitting People Who Mean Well. So, okay, so in other words, what's happening is higher efficiency means using less oxygen to maintain the same power output. So someone who is, at one moment in time, 20% efficient will put out less power at, say, 2 liters of oxygen per minute than someone who is 25% efficient who will put out more power. So high efficiency is very much related to Perponderance of Slow-Twitch Muscle Fibers. And so because we don't have a real paper to focus on today, we're just giving general training guidelines, I'm going to briefly look at a classic. So this is one from Horowitz, Sidosis, and Ed Coyle, who I told you we'd be seeing again. We looked at his paper for the FTP versus VO2max episode. So what we are looking at is trained subjects. who did one hour at the highest power that they could manage. And then subjects were then paired by high and low Type I fiber type and the amount of oxygen used during the one hour test. And what they did was they matched people who had the same O2 uptake during the one hour test and had different muscle fiber types. The first pair is a great pair example. So subjects one and eight were matched. So respectively, they were 83 and 46 percent Type I fiber. So subjects one and eight, respectively, each used 4.62 and 4.67 liters of oxygen per minute during the 60-minute time trial. So here's the kicker. Subject one missed a slow twitch. put out 357 watts average. And however, Subject 8 only did 335 watts. That is quite the gap for two individuals who consumed roughly the same amount of oxygen, or very closely to the same amount of oxygen. Yeah, yeah it is. So on average, the quote unquote slow twitch group put out 9% more power. So, why am I telling you this? What does this have to do with endurance riding and efficiency? Well, here's where we tie it all together. So, as our initially recruited, predominantly slow twitch muscle fibers fatigue, and we get into larger motor units that have more fast twitch in them, they become less efficient. So, as more muscle mass is used by recruiting more motor units, and less efficient motor units, oxygen demand increases. And so even if your larger motor units are actually more slow twitch, like Mr. 83% that we just talked about, there is actually more working muscle mass and that means more open capillaries. And so just all that kind of stuff alone is enough to increase O2 demand kind of no matter how it's happening. And so You know, there's also in the scientific literature, there's another thing called the mirror image, quote unquote, of this. So this is where the oxygen uptake remains the same and, you know, the muscle fiber recruitment presumably, but power output drops. That makes sense. You're fatiguing and therefore those motor units that you were, if you're just going to continually use the same motor units over and over as they fatigue, They're going to slowly put out less and less force over time. Yeah, exactly. And if you think for a little bit that like, oh, I'm below LT1, I should be, you know, this is very aerobic, I should be using all fats, like, no, that's not at all the case. We've talked about that before, that you're never actually burning only fat or only carbohydrate. Yeah. So what causes this fatigue is low glycogen. That is the primary suspect here. There's probably other stuff, but low glycogen is the big one that people have looked at. So researchers, I'm just going to briefly tell you about a paper. So researchers can find this kind of evidence in, okay, let me preface this a little better. So this phenomenon of heart rate decoupling during an endurance ride is if you look at like even textbooks that I have now that were published in the last five years, they suggest that during moderate intensity, which an endurance ride very much is, your heart rate and your blood lactate are going to remain stable. Your oxygen uptake will remain stable. Pretty much anything below the critical power, the FTP, lactate threshold, MLSS, Maximal Lactate Steady State, like however you want to measure that one thing, The very common old school suggestion that is still very much alive today, that I can't wait for it to go away, is that your body becomes like a machine in a steady state, and you can hold that steady state. Indefinitely. Yeah, literally. Well, the math works out like you can do it indefinitely, and some assumptions are like that too. Yeah, the CP model is like indefinite work. Yeah, for sure. Yeah, if you want to listen to hilarious things about assumptions for critical power, go listen to our FTP versus critical power episode. So nowadays, researchers can find evidence of heart rate decoupling in what they would normally think would have a steady O2 uptake and steady heart rate and all of that. In the literature, it's literally called moderate riding. Sometimes this means FTP. Anything under FTP, CP, they think of as moderate riding. But generally, it actually means endurance-paced riding. So something under LT1 that you can do for several hours. So the thing is, if you look at the evidence of your own training, and especially if you're a coach and you see your athlete's training, and you kind of start to understand the body a little bit, we can see that The body's not actually ever really in a steady state, no matter what. So an experiment in a paper that was done, I'll link it in the show notes, but we're not going to dwell on it too much. So what they did was on three separate occasions, subjects did 20 minutes of cycling at 50% VO2 max. The day before, the second and third of these rides, they did three hours of riding at 40% VO2 max. One of those times they had no carbohydrates that night before the next day, 20 minutes at 50% VO2 max. The other time they had lots of carbohydrates. And so the next day when they went in to do their 20 minute moderate riding, only while glycogen depleted did they actually find evidence of increased recruitment of faster twitch, larger motor units. Ah, interesting. So this kind of hints at the good old pro tip of those fasted rides that people occasionally like to talk about. Well, you're getting about 10 episodes ahead of us. That's on the list. So you guys are going to be excited to hear about that, I think. So the thing is, in a lot of the literature, this is a quick caution about it if you guys want to go dive into it on Google Scholar. A ton of the studies that look at this very thing, their tests are really short, 6 to 10 minutes. That's mostly what I see. The tests are too short. I've actually not seen anything looking at someone riding steady state for 5 hours on a trainer to look at what physiological parameters are changing as heart rate decouples. They usually look at it... above FTP, where it changes very rapidly, and that's very well studied. But with endurance rides, our experience as endurance cyclists, it kind of goes counter to what's commonly thought of in the literature. So if we oversubscribe to one particular model, we're actually going to miss the forest for the trees. So among other things that can cause this relationship also, a big one is heat, especially if you're riding on a trainer. So just know that, like, look at the conditions, indoors versus outdoors, and you can make a judgment on whether heat had anything to do with it. All right, so who's right? What do we do? So now that we have a better idea of what's happening, maybe we can make a determination here. The tool that we have is knowing how and why power and heart rate decouple. So if we're going to train by heart rate, let's look at what's going to happen. One of the things that I've heard of commonly referred to as the reasoning for pacing by heart rate, because if your heart rate is increasing, that indicates increasing internal strain. So the interval or the ride or whatever you're doing is actually getting harder for you internally. This is kind of true. but it's also kind of not because if we keep steady state heart rate and power goes down our working muscle fibers are still fatigued and you're still using them but you've decided not to access your larger motor units. So there's still internal strain on those muscle fibers. So all you're really doing is letting your smaller motor units that are fatigued just continue to put out whatever they can put out without getting into the larger motor units and letting those train up a little bit. And if you did get into those larger motor units, those smaller units don't turn off. This is part of the size principle, which you'll remember if you recall the last couple episodes that talked about the size principle. So no matter what, those muscle fibers are going to continue working. Just knowing that muscles don't act as one unit, beyond the very basics, I think that this is one of the most powerful explanatory tools that there is in all of training. I'm not exaggerating there. I mean that wholeheartedly. And I can think of only one situation where I might take advantage of this and give someone an endurance ride by heart rate. But let's look at assigning... Endurance Training Rides by Power. So riding to power is going to ensure that as your muscle fibers fatigue, we're getting into larger motor units and training them. To me, that's a good thing. So riding to heart rate and thinking about aerobic adaptive pathways. So with enough training stress, what is hopefully going to happen for most endurance cyclists is that you're going to slowly convert your larger motor unit Faster Twitch Muscle Fibers to Slower Twitch Muscle Fibers that will be more efficient. And even if you're doing other training that's going to maintain those faster twitch muscle fibers, if that's a thing you want, then you're going to make those faster twitch muscle fibers a little more aerobic. And even for shorter races, more slow twitch, better efficiency, you're going to get to the end of the race feeling better and not hanging on by the skin of your teeth in the last... 800 meters of a crit or something. Yeah, one would hope. So this is not actually the end of our options because there's one more because one of the drawbacks to riding to either heart rate or power is that, well, since they're coupled pretty well together early on when we're nice and fresh and we have lots of glycogen in our muscles, But knowing that even moderate exercise, quote unquote, does not have a one-to-one relationship with a steady state internal state of a cyclist, and knowing that fatigue of various kinds will affect power output and whatnot, riding blindly to power or heart rate can ignore all of the other things that are going on in your body that you can feel, but your power meter and your heart rate cannot. So I'm talking about riding to perceived exertion. And if anybody saw the meme I put up on Reddit. So riding to perceived exertion is actually how I assign a huge amount of endurance riding. So I'll put them down as like an RPE of 4 to 5, that's rating of perceived exertion, out of 10. Or the descriptive that I usually use is feel like you're working, but easy enough that you could do it all day. but still feel like you're working. So you're not killing yourself and you're not going too easy that it really is a junk mile. It's a good way to let athletes self-regulate and learn to self-pace and I find it generally makes the riding more sustainable because if you start a ride and you're not feeling good, ride for an hour as easy as you need to and then if you're feeling better, ride harder. So this is a lot like a story From a couple years ago on Reddit, I've tried to find this post several times, and I think it got deleted. I can't find it anywhere. So someone was saying that his power curve said he could do like X watts for like three to four, whatever it was, endurance type hours. And he would start his ride right at his average power target, but he would keep failing these rides. He never got close to like hitting that average power target for that duration. So I told him to negative split the ride. Basically, I told him to ride to perceived exertion, but I like put a governor on him like at the start. So I said, start really low. And then at the halfway point, ride only as hard as he felt he could. And then unexpectedly, he did it. The next day, he posts, he was like, oh my God, I can't believe I just did that. That was amazing. It felt so strong at the end. And he like, you know, beat his... Passed Best by, like, however many watts. And, you know, it works. It really works. So, using perceived exertion for this type of ride can let this kind of thing happen on every ride. Not that you should be, you know, riding within an inch of your life on every endurance ride. You should be tired, but you should not be, you know, contemplating. Delirious at the end of, yeah. You should not be having an existential crisis by the end of your endurance ride. You should go, I'm hungry. I will get some food. And not like ravenously like charging the fridge. So, and chasing more power every time can get unsustainable. I think that's one of the both, you know, the double-edged sword that is power meters and these quantifiable numbers is that For certain types of people with certain personalities, it can be great and it can be super motivating and it can be a useful tool. And yet for others, it can be almost a source of neurosis where like, oh man, this week on my three-hour endurance ride, I was six watts lower than last week. I must be doing something wrong. Like what's wrong with me? Oh God, I'm like, you know, losing all my fitness. And you're like, no, no, no, just like relax, relax. It's okay. It's like, you know. Yeah, no, you're exactly right. Yeah. It's like one of those first world problems, definitely. My power meter makes me neurotic over my training. Yeah, and if you are one of those people, riding like this, I guarantee is going to be a huge benefit, not only to your fitness, but to your mental health. It's like those people who say they weren't having fun on their rides and then they duct taped over their computer and just went out for a ride and they loved it again. Yeah, definitely. All right, so the next question to ask is, like I remember in Cyclist Training Bible, I think it was, Joe Friel talking about how when somebody's heart rate decoupling gets under 5%, or maybe this was on a TrainingPeaks article, that, you know, under 5%, then you're ready to go move on to the next thing, like you can start doing harder intervals. So, is this good? Is this bad? Is somebody whose heart rate doesn't decouple at all? Are they winning everything? So, let's look at it this way. The motor units that are initially used can handle that amount of work for that duration without fatigue. That's all we're talking about. So, through training, we can get a combination of using more muscle mass to distribute the workload, and we can get those working muscle fibers Trained Better. Which is happening? Very hard to say. But between training and eating enough, of course, yes, heart rate, I mean eating enough during your rides, heart rate can stay in lockstep with power and that is a good sign of fitness. I'm not saying it's not. But let's see how long you can do it. Can you do it for two days in a row? For four hours? Can you do it for five days in a row? For four hours each day? Can you do it for 21 days in a row? With some efforts like sprints and climbing some mountains in between. TTs. Yeah. At five and a half watts per kilo. Okay. So to me, it's like not only just a measure of fitness. I think that unlike what Frill says, seeing it under 5% on like a two-hour endurance ride doesn't mean you're ready to move on to a higher intensity. You know if you're ready to move on to a higher intensity just without any of that stuff. I am the hugest proponent of athletes being able to know their body better than the tools know it. And, you know, study after study actually proves this to be true. So if you feel you're ready to move on to sweet spot or whatever you're doing, do it. So like everybody says, like the old school piece of wisdom of, you know, I think I've heard Andy Coggin say it a thousand times. I don't know if he was the first one to say it. The best predictor. of performance is performance itself. So really, if you can ride for two hours at endurance pace with less than 5% decoupling on this ride, it really means that you can ride for two hours at endurance pace with less than 5% decoupling. Yeah. Yeah. So again, but if you're low on the ride time, but you like doing like FTP and sweet spot work, you know, honestly, you can find similar improvements there instead. There are some drawbacks to that. Again, we'll touch on it in another episode. You know, it's interesting, I just had this thought now after we have made it this far, but previously when we were talking about riding just a heart rate, it reminded me a little bit of what we were talking about last episode about progressive overload and that if you're only going to challenge the motor units that you got that you're actively using when you're riding just a heart rate, you're maybe not Overloading as much as you think you are. Yeah, well, that's a good question of, like, what is all this training actually doing? Are we getting into larger motor units and training them? Or do we just want to, you know, train these initially used motor units? Yeah. And, you know, if you ask me, it's both. But to me, it's almost impossible to tell. what the difference is and like that, you know, because, you know, we can get improvements in certain things by, you know, more Type I fibers, we can get it with more plasma volume, we can get it with, you know, better nutrition and we can get it with changing the workout schedule a little bit, you know, so it's hard to tease all these things apart and cycling and training and performance is so multivariate that it's impossible to say it's just one thing. To kind of wrap this all up, as old school and as maybe as mythic as this whole thing of perceived exertion and riding within yourself or being in tune with your body, in light of having all of these Advanced or more advanced scientific tools, especially in cycling, were one of the more quantifiable sports. If you're doing team sports, you don't have anywhere near this level of quantification yet, and even other endurance sports don't necessarily have this. You're kind of drawn into all these shiny toys, but this is a Good opportunity to say that you don't have to be married to your shiny toys when you're doing your intervals and stuff like that. And like you said, and I think we've mentioned this before, even when it comes to rest days and things like that, if you feel crappy, Skip a workout. Like you said, you want to be able to know your body and know how you react to training and know how you react to intervals and things like that. And this is sort of a natural extension to that. Yeah, definitely. I think one of the wisest things I've ever heard someone say, I think it was Dean Golich, who said you can't take intervals back. Yeah. Yeah, that's true. Yeah, I actually have one athlete. who, um, hi, how you doing? I know you're listening. Who told me that, um, while he's been doing all of these rides by perceived effort, he's not had power up on his computer screen at all, or heart rate. Yeah. He's just, he's just riding to his perceived exertion, and, you know, and, okay, so, actually, here's, okay, here's another piece of the puzzle. Maybe this is the actual last thing I'll touch on, is, um, if you look at his rides, You would think that I told him to ride by power. Like, the perceived exertion for staying in that steady state for a long time, like, he's nailing it. He is, like, so rock solid. And, you know, like, even though his heart rate is increasing and the ride is getting harder, like, you know, you could definitely feel the fatigue coming on, but it's the same perceived exertion for him. He's doing a great job, and this is good, consistent training, and he's going to be really, really fast this year because of this. I was going to say, that sounds like someone gave him some good preparation there. Yeah, well, I mean, like, he told me after, like, several weeks of this, like, I don't have power and heart rate up, and I was like, I couldn't tell that you... Yeah. Anyway, I think the other thing is that, you know, that if just... because I know there are people sitting there out there who think like oh man like perceived exertion like I'm either I'm such a wuss or I always go too hard or whatever it is also a skill that you can learn you know like you can use that heart rate monitor and that power meter to like learn the feelings too you don't have to just be a wizard overnight at oh I know exactly I can nail this perceived exertion no it is also a skill that you can train and you can learn so you should also look forward to Getting Better at That. It's another thing you can work on and focus on as a tool in your toolbox. Yeah, definitely. And, you know, as a coach, as somebody who, you know, teaches people how to do this, I can promise you that you will make huge strides in a very short amount of time if you actually start thinking about how you're feeling while you're riding. All right. So, as always, I want to thank everybody for listening. 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