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. And if you are new here, please consider subscribing to the podcast. And if you're returning, thanks so much for coming back. We really appreciate having you. And if you want to support the podcast in any way, well, of course, you can always share it. And we really appreciate that. Been seeing the podcast shared a lot. Thank you again. Always appreciate that. Thanks, everybody. And if you want to donate to the show, because we are totally ad-free, we are free content, you can donate at empiricalcycling.com slash donate. a coaching or consultation client, email me at empiricalcycling at gmail.com and right now it's about to be April so races are coming up and you know if you think it's too late to start with a coach or it's too late to get a second opinion on your season or your build for this season or whatever it is it's not too late it's actually never too late and if this is something you're interested in the earlier you get into it the better for you and for us and for everybody so if you're curious shoot me an email empiricalcycling at gmail.com if you would like to inquire about any of that and I'm also doing still weekend AMAs up in the Instagram stories follow me there at empirical cycling and also that's where we ask the questions for the podcast episodes and we got a whole bunch of questions for this episode so you see the purple background that is the podcast questions so as a follow-up to this at some point If we don't get interrupted by an April Fool's episode, we are going to do a follow-up 10-minute tips episode along with this to kind of think about the more practical side, the application side, the coaching side of this. But for now, we're just going to stick to all the nerd stuff because this is Wattstock, of course, and we also don't want it to go for three hours. I know a handful of you would like that, but my voice would not. We are also going to be, yeah, it's been a couple years since we thought about pacing endurance rides and like kind of the volume versus intensity and my recommendations have changed slightly but not really that much so we're going to talk about that in that next episode but today to follow up on the PGC1 Alpha Wattstock episode last time, you know, I really wanted to get into one of my very favorite ever meta reviews looking at the relationship between volume and Mitochondrial Adaptation. So there are actually a couple ways to look at and measure mitochondrial adaptation. We've kind of touched on these a little bit in the past, but today we are going to go really deep on this. And it's partly because it's fun, but also because it's a good way to understand. Yeah, my kind of fun. Partly to understand. what the measurements are being made and the upsides and the downsides of these measurements and how it may or may not accurately reflect the adaptation that we actually get. I mean, bottom line is, you know, we're always still looking for performance. If you have better endurance, you feel like you have better endurance, you feel like you can ride longer at the same power, all that good stuff, you feel like you've got a better sprint at the end of a race, all that stuff says better endurance. And there's no need to think twice about this stuff because, you know, why overcomplicate something that could be really simple? Well, I mean, we're all about why does this stuff work and how can we either, you know, support kind of the basics and drill into the basics better? And also it does lead to some good coaching application stuff. And we're going to talk about a couple questions that I get asked a lot. Between this episode and the next 10-minute tips, we are going to really dig into these. Like how hard is too hard for your endurance rides or your threshold or whatever. You know, we're looking at the actual adaptation of mitochondria versus how hard are you riding. Also the same thing for how easy is too easy. And then how much is enough. and how much is too much? You know, because is there a plateau? Is there a certain amount of volume where things end? Is there, well, that's one of the many questions we're going to do. So, Kyle, it's been a while since we talked about this. It's been like what? Well, the podcast has been on for five years now. So, there's that. Happy anniversary to us. Yeah, congrats. Wild, wild, wild stuff. Five years. Yeah. Who would have thunk? Well, not me, but everybody keeps listening and we keep getting more coaching clients. So thanks everybody for all of that. Empiricalcyclingatgml.com if you want to inquire. And we wouldn't be here without all of the listeners and people signing up for coaching and people asking the great questions. And I think I used to this time when I started doing the weekend AMAs, like what, four-ish years ago? Three, four, five, whenever. I think I probably got like 20 questions a weekend. Right now I think we're at like, I don't know, over 50. 100 maybe? It's a lot. You're going to have to hire a social media manager soon. You're just a big deal. I wouldn't trust a social media manager to answer these questions. I bet a social media manager would be snarkier than me. But, you know, so it's been a while. And, you know, it's... It's been a while since we thought about kind of this easy riding, like as a focus in the adaptation, because we've kind of dug into the signaling over the last couple of Watts docs, but, you know, the quote unquote zone two stuff, you know, power, heart rate, RPE, and, you know, how has the conversation shifted since the last time we discussed this, like, you know, what, four and a half-ish years ago? Yeah, I think, I don't know, Zone 2 is still one of those things where it seems really catchy. It's a buzzword. There's like a GCN video, right, that just came out about Zone 2, I think. And then now it's even funnier to me because I'll watch other content of like other, you know, sort of sports. Training stuff. And even non-cycling, non-endurance sports, people have picked up on the phrase, like, zone two cardio. Like, even for, like, team sports, which obviously that, yes, that is important. Like, if your sport is soccer or rugby or running, it's something that you run a lot. Like, yeah, in the off-season, doing something that resembles, quote-unquote, zone two cardio or zone two endurance or whatever they want to call it is, like, beneficial. But it's kind of funny to me how this is also sort of permeated out from the endurance world. But it, I think is always popular for a lot of amateur competitive cyclists because volume versus intensity in zone two and stuff like that because you're always limited on time generally and so you may not have the time to log three, four hour rides in zone two per week even though you'd like to but you know you have a job and a family and other responsibilities. So then the question is, oh, can I bump up the intensity and cut the time back and try to be more efficient with my time, even though in the ideal world, yeah, go out and just slam zone two coffee rides with my buds like all the time. Yeah, and actually one of the things that we've seen with like AMPK and stuff is that the harder you exercise, the more these signals get activated because, I mean, it just makes sense, right? Like if we, and calcium as a signal, you know, we're digging to bigger motor units and the longer you exercise, the higher the basal. you know blah blah blah and especially if you're untrained and you do super high intensity exercise we've seen this on the podcast before you get calcium leak that kind of goes away after you're pretty well trained but that's a that's a big signal too and so the you know that that intensity versus duration trade-off you know we discussed this on the on that time crunch training episode from god was it like two years ago now something like that yeah something like that yeah and you know it kind of came down to like you can only do so many hard intervals and yeah but at the same time I appreciate how the conversations change because like what five to ten years ago it was all about super high intensity intervals everybody was talking about sprint training and HIT and that kind of stuff and I appreciate that the pendulum has swung a little bit to the other side. It might have swung a little too far at this point. It might be swinging back. I don't really know. I consume very little of this training media. So yeah, I pretty much listen to the Inside Exercise podcast and that's just about it and only for selective guests. So anyway, anyway, so that's, it's good stuff though, I think, because I think without his popularity, we wouldn't be able to have the conversation that we're having now about this stuff because, you know, people want to hear about this and they want to know how do you pace it. And I think generally speaking, in a practical sense, before we really dig into the nerd stuff, the intensity, especially what we're going to be talking about today, like the intensities that we're discussing have all been assigned as a percentage of W max, as in the highest power output that you achieve in a ramp test. You know, your quote unquote VO2 max power. If you're curious about that, go listen to, what was it, Wastock, like 18 or something like that. But the reality is that we've got two thresholds here. We've got what we've been calling LT1, first threshold, and LT2 or FTP or MLSS or whatever you want to call it. The thing is that they kind of go up and down together, but they also kind of don't at all. So the downside of what we're going to be discussing today is that nobody's really done any kind of like standardization to these thresholds. The standardization has been done to Wmax, especially in these papers. And in the scientific literature, that's been historically the standard. And it's really a convenience for researchers for time and money. And I do not fault them at all for that whatsoever. And I think it really just kind of screws us on the application end sometimes because it's like, oh, this person wrote at 60% of WMAX. It's like, well, is their threshold 85% of their WMAX or is it 65%? Because these numbers matter. Yeah. I think that's a good point you bring out too where, we've talked about this before, that the disconnect between How you would design a, as a scientist, how you would design a study, and then how you would translate that into actual, you know, feedback or input into a coaching plan. Yeah, and especially in research, we're looking at averages, right? you know we're looking at does the average go up or down we're not looking at the individual and it's like when we really dig into the individual that's when we see all this wide variation and today we're actually going to see we've got some big error bars and some of the charts that we're going to look at today or the the figures from this paper and and I think that these like these or well you would call them confidence intervals so these 95% confidence intervals are fairly telling about the range that we see and so we're going to get into these ranges anyway so now now let's start digging in because what we're discussing here today is mitochondria and they're one of they're not the they're one of the big determinants of endurance performance especially muscular endurance performance and so building new mitochondria however you want to Think about that. And more of the proteins in it. So what are the most studied endurance adaptations out there? And one of the very first papers to really notice this was John Halsey in the 60s. And I think way more people these days should go read his stuff because like, you know, I remember what, five, no, not five, like probably seven or eight years ago, I graduated in 2014, I think. And so, yeah, right around 2014, 15, I was like kind of lost in the sea of physiology and what happens and why and all the like lactate and fat and all that stuff and then I started reading John Hollis' papers and everything became so clear to me so I think a lot of people should really go back and even though it's in the 60s you're gonna go wow this they really knew a lot like that big that big well-referenced Hollis' paper in the 60s with adaptation to endurance training like oh my god he's He lists out so much stuff I think a lot of people have kind of forgotten today. Not that it's anybody's fault. A lot of people are looking for new papers on blah, blah, blah. So, you know, there's always that pressure too, right? I mean, like, how many times have you been asked, like, can you get a more recent reference for X? Yeah, and I think that just happens just because if it's an older reference, not only do you not have it fresher on people's minds, but sometimes that when they're uploaded to any sort of electronic file, you know, paper service that the files aren't searchable because they're like Xerox scanned copies of like a typed out PDF, you know, a typed out paper that was then turned into a PDF and so they can just be harder to deal with because you can't control F them and everyone is so used to having a paper these days that you can just pull up you can actually digitally electronically search through and find what you're looking for and the older paper is just not the case or the figures are terrible because they were like hand-drawn figures and then like they got scanned and then now they look like garbage because the Xerox like way like ruined them with the contrast or something like that. Yeah, you pull up these older papers and it literally looks like that teacher's copy meme. Yes, yeah, yeah. And the other thing is like they are, it's like You're not going to find them. At least the newer papers, yeah, you might be able to go to a library that has a journal, the subscription, and then maybe you can actually find that in print. But the older ones, unless that library has been really good, they probably don't have, and this is like a research library, so not everyone's going to have access to this, but like a physical research library in person. You're probably not going to be able to find copies of these things. No, that's true. In real life. Actually, one of the things that I'm going to do is I'm going to add that John Halsey paper to the show notes for this episode. So if you're interested in this kind of stuff, I highly, highly recommend people go read it. Anyway, so mitochondrial adaptation, you know, we're actually going to do a podcast on noob gains in the near future too because we're going to start thinking about central adaptations and that's where people usually think about noob gains as like that immediate increase in power. And, you know, central adaptations are a big part of that, but the, but one part of noob gains that I think is a little underappreciated sometimes, including by me, I'm no stranger to this stuff, I'm guilty too, where the endurance adaptations are actually pretty rapid, like as soon as you start getting off the couch and start exercising, and Halsey's paper kind of gets into that, he was, you know, anyway, like I said, he's... the father of modern exercise physiology, really. Well, besides A.V. Hill. Him and A.V. Hill are the two big ones. So, a quick review from previous podcasts on the main benefits of improving this muscular endurance and mitochondrial mass, let's call it. You get better maintenance of energy state via spatial and temporal energy buffering. So, go check out Wattstock, I think it was 40 on that one. And this seems to be the primary determinant in sparing muscle glycogen because it's pretty clear now at this point that the scientific literature does not really see any sparing of glycogen by eating food. You can spare, well, not muscle glycogen. You spare liver glycogen like that, but not muscle glycogen. So this type of endurance seems to have a very outsized impact. It also seems to be better with recovery, not only from hard efforts. During Your Workouts, but also day-to-day, since mitochondrial are also central to many pathways in biosynthesis, and we talked about that in the Redox episode a little bit. We brush the surface, there's a lot more there. And also, you know, it's blah, blah, blah for health and longevity and stuff like that, but I mean, I'm always more interested in performance, because I mean, at some point... The exercise gets ridiculous and it actually starts becoming unhealthy for people, or it can, and that sucks, but we're really thinking about performance here. So, technically speaking, most of what we've been discussing expanding is what's called the mitochondrial reticulum. And, Kyle, do you remember your one giant mitochondrion joke from forever ago? Remember what I sent you a week later? Yeah, yeah, yeah. And then it turns out it is kind of true because mitochondria are able to sort of interconnect and share, share, share is air quotes around here because it's not like they're like, they have little hands and they're like, you know, passing things off to each other, but yeah. Yeah, a little reticulum, like what's a, how would you define reticulum? It's like the... It's like a network, I would say. Network, yeah, like a mesh, not mesh mesh, but yeah, kind of like an interconnected, sort of like interdigitated type thing. Yeah, like, so here's a way to think about it, is when you look at a cross-section of a muscle in biopsy, and we see mitochondria, and they look like little beans. And you're like, oh, it's a cute little bean. Like, what we're actually looking at is we are, think about it like a slice of a tree. We're actually looking at a cross-section of like a tree. These are like tree rings that we're looking at when we see the mitochondria and the cristae inside and stuff like that. So when you like get, this actually was done a while ago. Like this is kind of old knowledge, but I think everybody kind of forgets about it. I certainly didn't really know until I saw this old ass textbook. Or if you take cross-sections of muscle biopsies, like section, section, section, section, section, you stack them on top of each other, the mitochondria actually are this giant network that kind of looks like tree roots almost, but they're not getting smaller as they go. They're roughly the same size, but they branch and they go out and have multiple... Et cetera, et cetera. So it's kind of like, if you know what the endoplasmic reticulum looks like, it's kind of like an endoplasmic reticulum, but it's not clustered like that. It's just spread throughout, kind of like ivy through the cell. Maybe that's an okay way to put it, maybe? Yeah, I think that's interesting too, because I think it's one of those easy... sort of easy mistakes to make. Like, you see just a single slice, a single cross-section, and you assume then... It's a little bean, yeah. Yeah, you lose all the information sort of coming into and out of the page, right, if you can envision that in like three dimensions. Because you just have this now two-dimensional projection. And so anything that's sort of before or after that plane is lost. And so you don't know that maybe that does... And then you also lose information, like if you see another... Mitochondria, you know, cross-section, bean-shaped thing, somewhere else in that page, those two points might be connected because of some, you know, tentacle root type thing that is coming into and out of the page that you can't see, but you don't know because you aren't actually looking, you aren't actually looking at that and you've lost that information. I was going to say, based on the language that you and I both just used, I think people can tell which one of us actually took Calc 3 and which one of us did not. So actually, nobody actually knows how many mitochondria are in a cell. But there's a non-zero chance that the number is not like, you know, millions. It's like, maybe actually a very small number of continuous mitochondria. And that's, yeah, so, you know, it might be like... I don't know if anybody's done that. I bet it's maybe possible at this point. I really don't know. I haven't looked it up. But. the point being that that's why this is called a reticulum which you know as in a network and so when we think about the mitochondrial reticulum it's actually very difficult to measure how much is actually in a muscle cell because you know it's like yeah if you think about the endoplasmic reticulum it's usually depicted as like kind of like Blobfishes stacked on top of each other, like across sections of that, you know, like, or like a, like if you slice through a stack of pancakes that are kind of, you know, in volcanic shape, it kind of looks like that. And sometimes it looks like that in the cell, sure, but, you know, we're talking about echondry here. So, yeah, I think maybe ivy or like tree roots that don't like get smaller as they go might be a better way to picture it. So, and so when we think about the adaptations we're getting, One of the things that's not actually very well studied is this increase in surface area and volume, like total surface area or total three-dimensional volume of mitochondria. It's kind of an unknown thing. And one of the things that we're going to look at in this meta-review today is the handful of studies out there that use transmission electron microscopy. Because this is the actual gold standard, but there are very, very few studies. And I think this meta review says there were like six, something like that. So it's not a ton. More typical, because this, I haven't used a TEM. Kyle, have you? I assume they're large and expensive. I have not. Yeah, they're not inexpensive devices. And usually what happens is, A lot of places will have them. So for people who don't know, basically a TEM is instead of having a microscope that uses light, where light passes through, you know, your little classic picture of a glass microscope slide with a little glass cover and you've got some out of the little like amoebas in there or something and you look at them in high school bio. This instead uses a beam of electrons and it blasts this beam of electrons through. from one side of the thing that you're looking at and then is picked up by some sort of particle detector on the other side. But they're expensive. And usually they are operated by people who are specially trained or a lot of universities and schools will require you to take some sort of class or classes before they'll watch you just go in and use their very fancy, expensive pieces of equipment. That's a good question. I've never actually looked at them for cost. I sort of imagine that they're in the like, you know, Five to Seven Figures Range, if I had to guess. A lot of stuff is that sort of thing. Yeah. It's a large expense, and it is a large expense that a whole department will use university money to buy, not just a single research group is, oh, we're going to buy this $2 million piece of equipment. Right, yeah. And actually, we know a microscopist, and we should probably just ask him. But anyway, so... So that's a cost-prohibitive thing and an access-prohibitive thing for a lot of small research groups, especially people who are working on molecular adaptation to cycling. Like you said, not a lot of schools have this, and if it's there, you may not be able to access it. And it may be in a different department, where it may just be the sort of thing where you don't know because you're in the exercise phase. And sure, if you go over to Microbio and start knocking on doors, you might be able to find someone, but you have to know that it... This Thing Exists in the First Place and then, you know, hope that someone you know knows the person to talk to and things like that. Yeah, you gotta be dating somebody in the biophysics department for that kind of stuff. Exactly, yeah, there you go. Yeah, so a more typical measurement technique is isolating enzymes from whole muscle homogenate. And so what is whole muscle homogenate? Think muscle margaritas. Ugh. I'm not kidding. When I was in biolab, this is what we did. Like, we were studying an enzyme that was in tissue. The first one that we did was lactate dehydrogenase from bovine heart. And what do we do? We took cubes of heart and we stuck it. We literally put it into a blender and it waited until it was a nice liquidy mess. And then we put it in the centrifuge and started fractioning out what we needed. And so. With this method, you could easily imagine that the mitochondria kind of get parted out or, you know, they kind of get their cell surface gets disrupted potentially or they get chopped up into tiny little bits. And even when you spin in a centrifuge and you look at like the mitochondrial fraction of this, it's hard to like get a really good measurement of that kind of stuff too. And it's also hard to measure how many proteins are in it. So a lot of the time, you know, There's a lot of different methods that we could get into here, but it's easier to think about it for simplistic terms, just like you've put the entire muscle sample in a blender and you are measuring the activity of certain enzymes in it. And so usually citrate synthase is the big one. And we've kind of discussed this on the podcast before. I think we... discussed it in the AMPK episode at length. So citrate synthase being the entry point for the Krebs cycle where acetyl-CoA makes its way in and then the Krebs cycle starts stripping electrons. So in this case, using citrate synthase as a proxy for total mitochondrial mass, volume, reticulum size, whatever you want to call it, this is what's usually called mitochondrial content. Kind of means like, you know, just how much of the mitochondria generally is in this muscle. And so, and here's where we start getting into the weird stuff with these measurements, because you could read the literature for a long time and still not be entirely clear on what some of these terms mean. So, like, one of the things about this, though, is that The reticulum, like the surface area, the volume, the membrane area exposed into the cell, the enzyme content, like for our transport chain, Krebs cycle, important export shuttle proteins, and they don't always necessarily move hand in hand together. And in that mitochondrial overtraining study that we looked at a while ago, this is one of the things that they got into in that paper. And guess what? Their lead author is the lead author on this meta-review. Nice. So, yeah, so go figure, there's some kind of overlap in the approach to the analysis here. So... I think, oh yeah, that was Wattstock 41. Non-stoichiometric changes in mitochondrial protein content during overtraining. Some of it lags. And there was some really, really cool stuff, graphs in there, which took me a while to get my head around. But if you just stare at it for long enough, I find that it appears like a magic eye. So it's like suddenly it makes sense. And honestly, that's how I studied for biochem back in the day. And so also looking at Wattstock 47, it would make sense that The volume of the mitochondrial reticulum can sometimes outpace the synthesis of a lot of proteins in the cell because the cell that's exercising is not repairing itself. And so you might get one type of adaptation and some of it lags behind because you're exercising too much and you've got to chill and let all that stuff happen. Anyway, go listen to that episode. Yeah, we'll skip all the other details on this one. Okay, we're about to get into the paper, but we need to do one more thing. We kind of touched on this already, but I wanted to kind of bullet point this before we get into the paper. The signals, the adaptation signals that we've been discussing for the last few episodes, these are all signals that say we need more mitochondria because We've only got really a handful of like quote unquote programs that can get switched on in the cell in response to a training stimulus. And like in the last episode, we discussed PGC-1 alpha, which is kind of like a bottleneck for all of these signals. They get integrated here. And then, then this is like, okay, we got one big program. It's like, so if you're, you know, so if you're like reading something and it's like, oh, doing this kind of training means an increase in this kind of Protein that's, you know, part of the larger mitochondrial, you know, or the endurance adaptation quote unquote program as it were, that's one protein of many and if they measured all the other proteins you would see a lot of those other proteins too. It's like you don't always, you don't ever see just one protein increase in size unless that's just what you're looking for and that's the kind of interpretation you want to have for it. Realistically it doesn't happen like that. Does that kind of make sense? Yeah, I mean that also makes it, it kind of explains why things are, Hard to Measure. Yes. A lot of things in bio are hard to measure because of things like this. You're like, what exactly are you looking for? And then you have to correlate all these different signals, et cetera, et cetera, et cetera. Yeah. And sometimes, you know, it can also reflect how the experiment is done. And we're actually going to discuss that in great nerdy detail later here today. But, you know, it's stuff like if you take like cancer cells and you feed them different amounts of like lactate, for instance. Like the cancer cells that get more lactate, they grow more, go figure. And then you could look at like any kind of marker of, you know, genetic transcription or translation, and you go, wow, look, this lactate means this thing is growing. It's like, it's a cancer cell, of course it's growing if you give it food. Like, let's standardize a little better here with these things. So, the signals that we're looking at for exercise, change in cellular energy state. ATP, ADP, AMP concentrations. And this is really the main thing that's what we're trying to prop up as we get better with endurance training. We're trying to maintain cellular energy state. This is our big adaptive signal. This is why mitochondria are so good because we can do this aerobically, which means we can do it sustainably, kind of regardless of what fuel we use, carbohydrates or fats or even proteins. So protein. Yes, sorry. I know, I need food too. So when we're very untrained, you know, the energy state will plummet in a little bit and it'll yield a good signal during pretty much all intensities of exercise. And this is one of the things that John Halsey saw many years ago. Another signal, elevated calcium via CAMK. This is where... The Muscle Is Contracting So We Are Exercising It's All We Need To Know Redox Stress Via Sirtuins So We Get A Change In The NADH NAD Ratio Which Happens During All Sustained Exercise All Of It General Stress Of Exercise P38MAPK Via Mitogens Which Are Small Peptides That Usually Signal For Things Like Mitosis Inflammation The List Goes On It's A Very Long List So Even Epinephrine Which Increases the harder that we're exercising and we're increasing very, very hard. We get massive increases in epinephrine slash adrenaline slash catecholomies, we could just call them. And this helps with the transcription of PGC-1 alpha. And actually remember in the last episode how I said I had a short half-life and I mentioned, I think it was like two hours or something like that. I was way off. It's like 20 minutes. Ah, okay. Yeah, it's way more rapid. But, I mean, the conclusions don't really change. It's a factor of four between friends, you know. Yeah, it's not an order of magnitude like physicists usually think about as being large. So, yeah, so I didn't, I should have written that down, I didn't, that was my bad. But anyway, for our purposes, those are the big signals that we can think about that yield adaptation. And with that in mind, we dig into our main paper today. So, this is called Training Induced Changes in Mitochondrial Content and Respiratory Function in Human Skeletal Muscle. So, we encountered Granada before, who's the lead author here. And another author here, David Bishop, who's been studying AMPK quite a bit. I used a lot of his research for that episode and also for some of the other stuff. He's been really great. He was actually on it as an exercise and he had a pretty good interview, I thought. So the main point of this meta-analysis was to look at how manipulation of different training variables affects mitochondrial content and respiratory function. So what are our main variables? How hard can you go? How long can you go? That's the end of the list. Volume and intensity. Yeah. And usually people say frequency. But, you know, in these studies, frequency is, in a handful of the studies that they looked at for this meta-review, they changed frequency, but really, more frequency of the same duration just means more total volume. And so... Right, that's what I was going to say there. It's sort of... Yeah, there's sort of two sides of the same point. Degenerate with volume, yeah. Unless you're studying, like, what if I work out 15 hours in one day versus 15 hours a week? in one day versus spread out over six days. That's a paper I would read. Let's put it that way. So what we're going to be looking at in this paper is the actual change in mitochondrial content in various measures. So it's not really going to be just like, you know, the strength of the, you know, mRNA. Transcription after exercise after four hours and 24 hours or something like that. We're going to be looking at what is the actual phenotype change of the muscle. And a lot of this is based on citrate synthase, but we got a little more detail to go when we got new measurements that we're going to talk about. So this is going to be really fun. So this is actually, this meta review is a rare opportunity to really look at one of the main Actual physiological outcomes of endurance training in the muscles across different exercise intensities. And so we're going to see the range of adaptation for a variety of intensity and volume combinations. And this is going to let us make a fairly objective assessment about what is actually superior. And the answer is a little bit surprising, but it's also not at all surprising. I like a lot of the things that they did here. And one of the necessary evils here is they had to, like I said before, they had to normalize everything to ramp test values. But they mostly focused on cycling, which is great for us, because we are all cyclists. Well, most of us are cyclists. I know there are a couple non-cyclists who listen, so hi out there. So unless otherwise mentioned in the paper, they were just looking at cyclists, which means a really homogenous exercise modality, which helps with the analysis greatly. They also left out any papers that had incomplete information on the exercise protocol that was used, or they also left out any elderly or unhealthy and diseased populations. So we have a really good group of healthy people, some of them fairly well trained, and a lot of the cases not very well trained, but at some point, well, you can read the paper if you really want to. It'll be linked in the show notes. So the authors start their analysis by breaking down their categories for training-induced changes in mitochondria, and they've got three categories. They've got content, protein synthesis, and respiratory function. We're going to kind of gloss over protein synthesis, but But content, this is the one that I've kind of talked about the most on the podcast so far. It's a combination of how much mitochondrial surface area there is, plus how much mitochondrial protein content there is. And that's for this paper, for this meta-review. So here they're using basically citrate synthase because it's so commonly measured, but occasionally in other papers, we'll see electron transport chain proteins like SDH. Will get measured, and that's a kind of crossover between Krebs Cycle and yada yada. Sometimes it'll be like HAD, and there's a bunch of ways that other papers have done it. We've talked about those, but here they standardized it to citrate synthase, which I think is actually really smart. So for protein synthesis, it's actually way too in the weeds for this episode, and we don't actually get a ton of actionable information on it. It's interesting to read. But for our purposes, we can really just ignore it. Because this is like the first step in adaptation response once the aforementioned signals actually get sent. And, you know, it would be measuring like how much of certain key proteins are made immediately in response to training or even in, you know, 24 hours or something like that. So most of these studies are in the meta review, or all of them rather, are looking at just what's pre-intervention and post-intervention and that's it. They're not looking at the immediate response. So the last one is respiratory function, which means mass-specific respiration, which is to say if you isolated just your muscle sample or your mitochondria and you measured the VO2 max therein relative to that weight. And usually this is like picomoles per second per microgram of mitochondria. In other words, very, very small. Very, very small. Like, how many zeros are in picograms? Pico is 10 to the minus 12, right? Nano, it's like, yeah, nano is 10 to the minus 9, Pico is 10 to the minus 12. Yeah, okay. Thank you. It's a lot of zeros. A lot of leading zeros. I don't want you to spend a lot of time thinking about picograms in my life. Picograms are, like, there are still, you know, like, this is kind of looking, It's actually pretty impressive that we're able to measure such small amounts of things. I always find that pretty fascinating that, you know, you think about, okay, what's a gram in your life? Like a gram about, you know, the mass of, say, like a paperclip or something like that, right? And so imagine chopping that up into 10 to the 12 pieces. And then we have things that can measure that. It's kind of cool. Yeah, I agree. And actually, whenever somebody overspends on a bike to save like 50 grams, you should show them in paperclips how much money they spent. They're like, you just spent $2,000 on these 50 paperclips. Anyway, so the one last thing to note about the standardization stuff in this paper is that when they discuss volume and intensity, they had to standardize across everything. So for intensity, I quote the paper here, quote, Exercise intensity was expressed relative to the maximal power output Wmax or estimated Wmax based on the bioenergetic model, unquote. Bioenergetic model meaning the critical power model. So this is really standardized stuff. And it, like I said before, it kind of misses the thing about threshold kind of appearing as a range relative to Wmax, but we just have to live with it here. For volume, training volume. Okay, sorry, quoting the paper now. Training volume was calculated by multiplying the exercise intensity relative to the Wmax or Wmax prime by the duration of exercise training in minutes by the total number of training sessions, unquote. So this is actually a direct correlate to what Kyle, you and I have been calling the area under the curve way to consider aerobic signaling. How hard is the stimulus and how long is the stimulus going for? So, does that need any further explanation, do you think? Or does... Yeah, I mean, it's just... Yeah, it's looking at, so just for people who aren't familiar, right, with area under curve, you're looking at not just, like, how long something goes for or how tall the maximum signal is, but sort of the... It's the sum of all of it, so... Yeah, and we can tell... And there are... Sorry, go ahead. Oh, I was saying, and, like, the other thing with area under the curve is that there are many different, perhaps, an infinite... number of different ways that you can draw curves that come up with the same area. So it is both instructional in that way, but also depending on how you do it, you may have to be aware that you can have very different curves that integrate out to the same number depending on what you're looking at. Yeah. Is that related to our discussion on infinite sets earlier this week? Kind of, yeah. Yeah, yeah. Oh, God, I thought so. Oh, no, it's my nightmare. Coming back. Calc 2 coming back at me right now. Okay, so now we know their methods to standardize things for this meta review. And, you know, I'm not terribly happy about it, but I'm also like, there's no way you can fault them for it because this is just how things are done in exercise physiology these days. You know, especially with like RAM tests and saving time, you know. You hook somebody up to a ramp test on a bike and you get their VO2 max and sometimes you measure lactate and it's been pretty standardized for a very long time. So the other thing to standardize in this paper was what counts as different exercise intensities. And so what they really did was they broke down the protocols individually paper by paper and they labeled them. So you'll actually see like a moderate intensity, continuous training. at the same percentage of WMAX as like a HIT, high intensity interval training paper. Like they overlap in quite a decent range. And so it'd be like, wait, what's going on? So they look at the protocols and they kind of assigned it based on that. So MICT, M-I-C-T, middle intensity continuous training is, was assigned as 45, I know, 45 to 75% of WMAX, which can be all the way under LT1 for some people and all the way over FTP for others, but it's a decent range and for the average, it's fine. Sprint Interval Training, SIT, is basically anything over 100% of WMAX. Most often, it's done as like 30-second sprints in these protocols or the papers they looked at. They looked at quite a few. So the other one is HIIT, High Intensity Interval Training. They assigned these as intervals done at 75 to 100% of Wmax, which can be FTP for some, but eliciting VO2max for others. And these are rough definitions. And like I said, they classified all the papers they looked at individually. And in the text of the papers, they actually discussed the individual papers interval protocols and all that stuff. kind of at length sometimes to illustrate different points about, oh, this paper found this, this paper found this, when they're trying to address questions that their meta-analysis has brought up. So the studies on content or volume density is the big section for this paper and has most of the juicy stuff. And they start by looking at only six studies that use the gold standard of TEM. for looking at training interventions in healthy young participants. Six out of like, I think they looked at in total maybe 70 or 80 papers. We've got six here. So to me, this is interesting because, well, they also only had healthy young participants. Like not, they didn't have any trained cyclists in this stuff. So there's that. But I wanted to bring this up because They have a really interesting range for change in mitochondrial volume density. And so they've got a range of 1.1 to 1.6 fold change. That's a big range. Yeah, that's a pretty surprise, like, you know, and keep in mind, none of these are like, you know, 10 year long studies or something, right? Those things just don't exist. Yeah, I think the longest study that they looked at was like 12 weeks. No, that's a lot. 12 weeks? Yeah, that's a lot. That's halfway to getting somebody ready for a proper race. So, I thought this was interesting because it actually shows a lot how variable the individual response can be to the same protocol. And another reason that individualizing training helps a lot. Some people need a little more, some people are fine with less, and, you know, sometimes... When we get into the weeds of this stuff, there can be a selection bias at play. When we look at, oh, this worked for this person, this didn't work for this person. You've always got to not compare across people like that because you get a lot more variation between people than even between groups of people. So the downside also of these protocols is that not a lot of long-term study on this, kind of like I mentioned. So when we look at the papers figure one, we actually see a plateau. in mitochondrial volume density as volume gets to about 100,000 AU. That AU being arbitrary units, not like astronomical units, Kyle. Sorry. I was going to say, these are big, very large. Yeah, you're like, oh, I thought they weren't that well-trained. They did 100,000 AU. Wow. Yeah. So we cannot draw many conclusions about what happens in the super long term with well-trained people. And the authors also conclude the same thing. But I wanted to really just highlight the variability here with the few studies that use our quote-unquote gold standard. But we can draw some great conclusions in the next section. This is the real meat of the paper. They spend the most time, most body of the paper here. And this is where we can actually make the most conclusions too. This is where we're measuring mitochondrial content by citrate synthase activity. You know, like I said, it's the entry point to the Krebs cycle. And with endurance adaptations, so we not only need to have more electron transport proteins to make ATP to maintain the energy state, we need to strip more electrons off of food stuff to supply that stuff. And so check out Wattstock number 29 to 33 for explanations on that. And sorry, they're basically biochem lectures. I tried to make them as interesting as possible, but I knew if I just said, go look at these things, nobody would go learn up on what happens with like, you know, fat breakdown, etc, etc. So anyway, that's why citrate synthase is an enzyme that's been fairly well associated with endurance adaptations and is so frequently measured because it's such a critical part of adaptation and the entire quote-unquote machinery in order to you know strip energy from food um so measuring citrate synthase activity from whole muscle homogenate also means they're measuring whole muscle activity which is an upside and a downside because the upside is we don't need to control for individual motor unit recruitment which in a way might actually be impossible to do with any precision at all um but on a downside we're also not Controlling for Individual Motor Unit Recruitment. So, you know, we're looking at whole muscle activity. So if we get higher exercise intensity, we might have citrate synthase activity increasing in more muscle fibers than we would use just riding easy. So that's kind of the downside here. But the nice thing is we can fairly compare different studies and different intensities, which we can do here. So we've got 56 studies total in this section. And the headline news is, Greater training volumes are associated with greater citrate synthase activity. R equals 0.59. But, and Kyle, you can scroll down in our notes here to figures 2A and 2B. But when the authors remove... Yeah, hold on. We're going to get to that. I want to set this up right. So when the authors remove the sprint interval training studies, the R goes up to 0.71. And as far as your data concludes, Well, we can save that juicy little mic drop that's coming up for a second. So yeah, go ahead, Kyle. Tell us what's in these figures. Yeah, so there's a lot of different data points, and it has, on the x-axis, it has training volume, and it goes from 50, sort of 0 to 250,000 arbitrary units. And on the y-axis, they have CS activity. So it's the fold chain. So it's kind of confusing because it goes from 1 to 1.8. And you think that's not very high, but it's actually looking at, like we said, it's a fold chain. So it's like doubling. It's like an exponential kind of logarithmic type scale, not just a linear scale. So it's not like going from 1 to 1.2 is not 20%. It's an exponential. the generally speaking sort of if you envision these points they're kind of scattered about and there is a trend sort of that more of the points at the higher training volumes see more of the more response in the you know the CS activity which is good it's kind of what you would expect You'd hope, oh God. You'd hope blocking more time. But what's interesting is that there are definitely some big outliers that, like, so generally you have a clump in the middle that kind of is in that sort of monotonically increasing direction with more CS activity with more training volume. and then like you said in the one plot they've included the sprint intervals and then in one plot they've removed them and the correlation sort of between more CS activity goes and training volume and more training volume goes up when you actually remove the sprint interval training and if you actually look at where the sprint interval training data points are clustered a lot of them have relatively low training volume because that's like one of the selling points of That type of training, right? Is that you don't have to do that much time and they're all really hard and so you get a lot of sort of time efficiency. But none of them go particularly high on the activity on the Y-axis. Yeah, like the highest sprint interval training that you see is like 1.5-ish fold change, but the volume doesn't go anywhere. Like the highest volume we see for the SIT studies is like, what is that, like 40,000-ish? But like the average, like the middle of this chart here is like 150,000 or 175-ish, or sorry, 125 is the exact middle. And you get similar numbers, like a lot of, so sort of yes, in the sense that the highest like sprint training number that you see is sort of in the 1.5-ish, but You see a lot of the other types. All the other types of training can offer a similar amount of activity increase, but with substantially higher training volumes. Not that that means that it's substantially harder, but the sprint interval volumes are just so low that you think, oh, the difference between 10,000 and 100,000 of these arbitrary units, like, yeah, it's a lot, but when you talk about the total amount of time in the sprint interval training, it's just not that high. Yeah, and they're all so clustered around the bottom. I mean, no wonder they're really kind of thrown off the R of this, you know, linear regression. And one of the other things, though, is that you couldn't do a ton of sprint interval training, you know, to 200,000 arbitrary volume units. Like, there's no fucking way, because you're just going to be so tired. Maybe you couldn't. No. I absolutely could not. No, that's right. It would be really, really hard and it would be a sort of a death march. Yeah, for sure. And so there's one of the other things I like about this or not that I like, but that I notice about this that kind of leans into the way I like to train people is that it doesn't seem like there's an upper limit. Like it's not like this is plateauing. Like this is just like a line straight up. And the range, you know, it's a fairly wide range. So at basically zero arbitrary units, we have anywhere from like a 1.3, no, sorry, 1.1 fold change up to like 1.4. That's all the way at the, like the bottom, bottom. We go up into the middle range, we're at like a 1. 2.5 to 1.5 fold change or, you know, 1.6 fold change is the range. We go all the way up to the top and the range is like 1.5 to like 1.8. And so that range just keeps going up and up and up and kind of regardless of what exercise modality is like, the middle intensity training, high intensity training, which could also be a two max slash FTP intervals, who knows what they were for these people, like more is more. And so, realistically, this suggests, we obviously need further research, but this suggests there's just really no upper limit to the volume, where the more you can ride, the better endurance you're going to have, and in my coaching experience, that's exactly what we find, and when we run into issues with how much can people ride, it's not like we really find, I mean, there are some diminishing returns, obviously, but... I find that if people could recover faster, they could be even more fit by riding more. And it's the recovery that really limits us rather than the actual like, you know, like the riding adaptation itself, or the stimulus rather. Yeah. And that's interesting because we've talked about this before when you talk about like, oh, if people are, how do you know whether someone's actually at their genetic max? And it's like, yeah, if you're not a... Pro, you're generally restricted just by how much time you have to train and recover. It's not like you, most people are not going to reach there like, oh, I'm just totally tapped out on my fitness and I'm never going to get any faster on my nine hours of training a week. Yeah. Well, the other thing I was going to say is that we're also looking at full change. We don't have a baseline here. We're looking at full change relative to the person. So somebody could have amazing natural endurance abilities. And somebody could have, like me, really bad ones. And, you know, we're not looking at like, what is, you know, what is somebody's peak potential for endurance here? We're looking at just what is the change from what they had before the intervention? That's all we're looking at. This doesn't say that, you know, if you just ride more, you're going to get... You know, you're going to have endurance as good as like Pogacar. Like that's not going to happen. Or it might not. It might also. Who knows? And I think also a lot of people are thinking about when they think about improvements, they're mostly thinking about the power, the absolute power output. What's my FTP? What's my watts per kilo? And we're talking here about endurance. We're not talking necessarily about increasing your VO2 max. We're talking about muscular endurance. And all my data says you ride more, you've got better endurance. You still have to do intervals. But, and we're going to get into much detail on that in just a little bit, but this is pretty much the match between the data here and my coaching experience. That doesn't mean that you have to ride more, and also, of course, this means that some people can ride 10 hours a week and still have great endurance. You know, their training history matters a lot too, so we can't really make any conclusions about any one individual, but as a whole, we can certainly make conclusions that riding more is Better for your citrate synthesis activity fold change, to be technical. Yeah. But I think this means that, you know, it also, like you said, with a lot of these studies, and this probably matches people's experience, that, you know, because these were not very well-trained, experienced cyclists, like, this is definitely what you would class as, like, noob gains for some of these studies, where, like, oh, man, they were generally healthy, Active, but hadn't really trained cycling, and then all of a sudden in the first three months they saw really great improvements, right? And a lot of people remember that when they first started riding in a serious, controlled, sort of planned, periodized manner instead of just riding around. Even as much fun as just riding around is, you know. Yeah, that's true. I get that. Well, that actually reminds me, I got one more thing to add to my list of... of mistakes that intermediate and advanced people make for that podcast that we're going to do eventually. I've got notes on a lot of this stuff. And that is one of the mistakes is thinking that your noob gains are going to keep going for when you're an intermediate and advanced cyclist. Oh, that'd be great. I know, right? Anyway, so part two. But how hard should we ride? Kyle, how hard should we ride? So I've included in our notes. Exactly as hard as needed and no harder. In a way, yes. So I've got figures C and D here. On the left, we've got, again, with the sprint intensity studies here, and on the right, without them. So why don't you describe kind of what we're looking at? These are all going to be in the show notes, too. Yeah, it's a little confusing because it's also, there's a lot of points, again, not surprising because, like you said, they looked at a lot of different studies. you have a like a I would say a general cluster of all of the other programs that were not the sprint interval training and sort of the 50 to 100 percent of WMAX range which is makes sense with the descriptions that we gave. So the x-axis is like relative intensity percentage of WMAX from 0 to 400 percent. But on the right where they excise the sprint interval training, it goes just from 40 to 100%. Yeah. But there's a big clump of the sort of non-sprint interval training where it's just kind of that, it's almost kind of Gaussian shaped actually, like a pretty high, taller cluster in the sort of 60 to 80% range, then fewer programs that... that wanted people more down to the 40-50% and also fewer programs that had people sort of up above 80% and then there's this whole band of sprint interval training at the 175% all the way up to this one program at 350% which is like oh god. Which also has very low fold change. It's like 1.1. Yeah. But you tend to see on average the programs, like if you were just to average out all of the programs that are not doing sprint interval training, their fold change on the y-axis would average out higher than the sprint interval training average. Yeah, we're looking at like 1.3-ish versus like for sprint interval, the middle of the road is like 1.25-ish. It's not a huge difference, but you can definitely see it. It's not a huge difference. But it's clear. And you can also see that, you know, sort of there is a much not hard cap, but there's a much firmer sort of peak that the sprint interval training programs never crack above, like we said, that 1.5, and you have several data points from the grouping of all the other programs that exceed that 1.5. Yeah, the range, except for those kind of, well, they're not really outliers, they're real results, but like, You know, those upper limit, because from the super high volume training studies, this is what we're seeing here is like, we're looking at 1.5, 1.55, 1.58, 1.6, 1.75 fold change for those really upper limit. Now the sprint interval training, like, yeah, there's that kind of like cap at like 1.4 and part of it's probably because you couldn't get to higher volumes, like we just said, but also, you know, for you know fairly noob gaining kind of people this does show uh well not that all of these participants were noob gaining people but um you know there were definitely some trained cyclists in there but we are definitely looking at you know some equivalence of these two things like you know a lot of people have kind of discussed and you know they're not wrong about it yeah so on the right here the other thing is oh yeah sorry go ahead oh the one other thing i think is is unfortunate is the um You have a couple, two, three data points down of the sprint interval trainings that are down in the sort of 100% level of Wmax and they're interesting because they're pretty close on the x-axis to a bunch of the other traditional, maybe we'll say more traditional training modalities and the results are Comparable or maybe slightly worse. Yeah, actually, yeah, very much true. Well, I mean, because also, no, we don't have to get into that. Anyway, so on the right here, they've excised the sprint interval training studies again. And so now we actually have, we can actually look at the distribution in the ranges that normal people train in, which is We've got 40 to 90% of Wmax for these protocols here. So tell us what we're looking at. Yeah, it's broadly Gaussian. I would say that the sort of relative intensity exercise, the average of these sort of more traditional programs is somewhere in the high 60s percentage-ish, maybe just under 70. And that's actually the range where you see the highest CS activity as well, sort of in that middle range, sort of between 60 and 80%, you see the points that show the highest activity. And if we go up, actually, that's one of the studies that had the highest training volumes too. That was a 225,000 AU. Yeah. Oh, that makes kind of sense, I guess, if you think you're logging a lot of volume of moderate intensity, but then it... It's sort of the CS activity tapers off towards the extremes of, you know, sort of the 90% level. It's sort of interesting because you can look at a bunch of the programs in the 90% level saw very similar results to a bunch of the programs down at the 45 to 50-ish percent intensity level, which means that they were doing a lot of hard work and getting... They could have like cut the intensity in half almost and got the similar results, which is kind of rough. Yeah, yeah. Mentally. Well, one of the other things I noticed here is that the, um, And so that's one of the reasons that We may be looking at selection bias. If we had the same amount of studies at the low end and the high end, we may actually see a wider range of CS activity, potentially depending on the volume that you could do. And at the super high end, actually, one of the things I think is interesting is that that cluster at 90%, they're all HIT except for one middle intensity training. or MCT as you would read it. Oh God. I know, that's why I haven't been saying it. I also can't bring myself to say HIIT training either. So that cluster is, you know, when you're doing interval training like that, you are limited by fatigue. You are limited by how much you could physically do. And so in the middle where you're looking at being able to do more volume, That's where potentially we see the highest improvements. And the average though, the average across all of it is about the same 1.3 fold change. Yeah. Yeah, yeah. Like it's like the R is negative 0.01 for this distribution. Yeah, which basically means it's not correlated. Yeah, zero. Relative intensity is not correlated to the CS activity. Yeah. So this is something that is fascinating to me. Because the first time I saw this, I went, no fucking way. This paper came out in 2018, by the way. And I saw it, I think, like, late 2018. I was like, really? You're kidding. That's so cool. So it's, I'm just, sorry, I'm just marveling at its beauty right now. Like, because you would think, If you had, if higher intensities yielded higher CS activities just because they're higher intensities, you would see a positive slope here. And it's flat! Yeah, it's super flat. Yeah, and in the middle, you know, most volumes for these studies, you know, they're not exactly, you know, spelled out here, but Basically, the highest volume shows the highest change, and it's right in the middle. And I'm sure if somebody had lowered that intensity and had people do even more volume, you would probably still see a similarly high increase. And so this is the big conclusion here, is that according to this data, the intensity is much, much, much less important than the total volume. Way less important. The bottom intensity here is 45% W max. 45%. This is about, I would say for the average person, somewhere around 60% of their FTP. And it doesn't look like it's dropping off at that point. It's flat, which means you could probably ride at 50% of FTP and get about the same thing. And so, yeah, sorry, go ahead. Oh, no, no, I agree. And we've talked about this before, right, where sometimes people get hung up on exactly what percentage and they're like, yeah, these are kind of zones. So you can kind of round and squint a little bit one way or another and it's fine. Yeah, actually, that episode I did with Rory about how training zones screw you or whatever the title was, I had this written and I deleted it at the last second because I'm a chicken, but it was originally going to be there are no such thing as training zones. And this is one of the things I was thinking about when I wrote that. Ah, yeah. But, I mean, but I went with a more practical, like, you know, how they're steering you wrong or something. Because when you think about these training zones, oh, I have to be in this range to get this adaptation. You fucking don't. It's pretty clear. And this is why for a long time I've said FTP is spicy endurance. You get a lot of the same muscular adaptations as you do at lower intensities. It's just harder because obviously we're recruiting different amounts of muscle mass and yada yada. And so they're not exactly equivalent, even though in this sense, in some ways they are. But it's a less important distinction than I think a lot of folks would think it is. Much less important. So yeah, so kind of my reading of this is that for the same unit volume, regardless of intensity, the average adaptation of citrate synthase activity across all studies was about 1.3 fold change across all. And so the intensity less important than the volume by a lot. Does that mean there's a minimum intensity? Does that mean you can go out and ride at 20 watts? No. Obviously, you cannot do that. That would be way too low, even if your FTP, yeah, even if your FTP is like 150 like mine. Sorry, my 200. We've talked about this. We want to have that study of like, what is the lowest volume, lowest intensity, like high volume that you can ride at and still see gain. So like, is it under triple digits? Probably under triple digits, right? It's, you know, I think it depends on 15 hours a week of like 80 watts. Yeah. Well, for somebody like me, my threshold is actually about like 210 right now. And so for me, my easy endurance riding is like 60 to 80 watts. Sometimes I go up to 100. And if I go outside, I'm having fun, and I'm on a good day, and I feel like smashing a little bit, I'll average 140 for two, three hours. And that's fun. It's hard. Could I do that day to day? No, absolutely not. Even at, even writing as much as I do, easy, which is like, what, somewhere around six hours a week right now? So it's not a lot. But, you know, it's enough to, it's enough to keep me healthy. There's that H word again. But yeah, it's like, it's, I know for a fact that what we're really dealing with here, and we're going to really dig into this in the next 10 minute tips episode on this, is fatigue management. because if you cross over that LT1, you do six hours there and you do six hours just under it, the fatigue is disproportional. Once you get over a threshold, you gather a lot more fatigue and you get just a tiny bit more adaptation and it's not worth it. And FTP is the easy one. Like you ride at 110% FTP versus 90% FTP. 110%. Oof, yeah, oof. Right? Like, you and me, we can go longer than most people at 110%, but it's not going to be equivalent to, like, you know, going more than twice as long at 90%, because the duration is going to be so much more impactful there. And it gets real hard at the end. Like, if you've ever done that, like, made the mistake of, like... Thinking that you can hold just a little bit too much and you think you're starting out fairly aerobically and then it starts to kick in that you're pretty not working over your aerobic maximum. You're like, oh, this is getting bleak. Yeah, when you're trying to get that, you know that one minute where you're controlling your breathing, you're like, nah, it's not that hard. And then a minute later, yeah, like severe regrets. Yeah, that's a good time. And sometimes it's It's just that slow descent until, like, you just try to hold on and, like, white knuckle, but that's, it's a different workout, right? That's, that's an entirely different workout than, like, a high-tempo workout. Very, very different. You should not be white knuckling the end, you know, all the time. Yeah. Every, or the end of every interval should not be a white knuckle experience like it is on, like, VO2 maxes or something. I agree. Yeah, like, just, you know, at some point you're like, that was some hard work, just, you know. Unless that's the workout is to go that deep, especially if you're doing threshold intervals, like, you know, it starts getting hard. You're like, oh, I better catch my chips and get out of here. Like, this is going to turn on me real quick. Like, yeah, you made it. You escaped. You beat the house. Anyway, so the other section of this paper to get into, I can't believe we're at over an hour right now, but there's one more section and I want to get into this because this is... A paper, the section of this paper on respiratory function. And I would normally skip this section because, you know, we just got through all the big stuff. If you want to skip to the end for listener questions, be my guest. But this section for me, I think, is necessary to include at this point in, what year is it? 2024? Yep. I was going to say it's 24. Well, it's March 24th. And I was like, is that the day of the year? Because they're usually not the same. Anyway, sorry. The mitochondrial function phrase is everywhere that I see. And it bugs me a little bit, not only because I'm pedantic like this, but because mitochondria have a lot of functions. If you say mitochondrial function, which function? It would be great for somebody to clarify if they use this phrase, which function? The function about calcium buffering? The function about apoptotic signaling? The function about biosynthesis? The function about, oh, respiration, okay, cool, respiratory function. And that's what this paper's looking at at this point. And I'll warn you right now, this is some pretty hardcore nerd stuff, so I'm looking forward to it, but if your eyes gloss over, Don't worry, and I'm sorry. Yeah, this is your pleasant reminder that your mitochondria do a lot of things that aren't just like help you ride a bike. They're very important for a lot of other reasons. We've looked at those studies, right, where they knock out in mice various mitochondrial functions. They don't lead very high-quality lives. Yeah, and people with actual mitochondrial diseases... do not have easy lives. They really genuinely don't. And it's like, oh, are my mitochondria dysfunctioning? Like, can you see? Can you walk? Like, yeah, you're probably fine. You just need to exercise. That's all. Which is a gross simplification of, yeah, of exercise and yada yada and health. But yeah, CDC recommends like, what is it, like three hours a week or something? Yeah, it's 150 minutes of like basically slightly over walking intensity exercise a week. I mean, honestly, from having, you know, from my hip injury and like barely exercising for quite a while besides lifting, as soon as I started riding about three hours a week, I actually felt my health improve. So I'd say there's some merit to the CDC's claim. I'd think, you know, if you go to six to 10 hours, it'd probably be a lot better, but who knows? You don't have to ride hard, you know, especially if you're looking for mitochondrial function. So which function are we talking about? Respiration. So anyway. This is an aspect of training that's been observed in previous studies. But in a lot of ways, it doesn't seem to have a specific thing in performance that we can tell. And so that's the kind of caveat here. But we've encountered mass-specific respiration on the podcast before, especially in the previous Granada study, Wattstock 41 or 2, I forget which one. But we kind of glossed over the technical explanation other than to say it was like, you know, the mitochondrial mass specific VO2 max in a way. But here, the standard for these papers is actually not to isolate the whole mitochondria, you know, and then check them out. But it's actually looking at permeabilized, did I say that right? I've been reading this word and I don't think I've said it more than twice ever, permeabilized muscle fibers. Muscle fibers were the cell surfaces made permeable. And so this is mass specific respiration. And this term in this paper means, usually means Muscle Sample. Instead of grinding up the muscle sample into a margarita, spinning in a centrifuge and taking out the specific mitochondrial bits, we're not looking at that. We're looking at we leave the mitochondria in the cell. And basically how this works is imagine your cell is a house and you want to know what's going on in the house. And so you knock down all the exterior walls. But you try to leave as much of the interior alone. And the holes are pretty big, especially because you're in solution here. You are immersed in a liquid. Small stuff gets washed out of the holes. Like I'm looking at a paperback right now. This is going to get washed out. But my desk is not getting washed out. And so it's just too heavy. And I mean, I actually looked up how big are the pores that get made with this stuff. And they're about two nanometers. And I had... Oh, sorry, go ahead. Oh, that seems pretty big. For a cell, it's fucking enormous. Yeah, that's pretty big. It's like a garage door. Like, you could drive a car out of that thing if you were a cell. But I looked up some of the sizes of... Magic school bus. Yeah, well, I looked up some of the sizes of certain proteins in order to... Because I'm thinking about some of the results they got. And, you know, like, myoglobin is three nanometers. Not Two. So like that's probably going to stay in the cell. But there's a lot of small stuff that'll go away. But the cytoskeleton stays intact. And the mitochondrial membrane stays intact. Nuclear membrane, I'm not sure about. The endoplasmic reticulum membrane stays intact. So in the muscle cell, that's sarcoplasmic reticulum. And one of the things that happens, well, one of the things that we're doing is actually we are... using the what's a plant toxin called saponin or saponin. I always say saponin. I don't know which is correct. And this is actually a really cool aspect of plant defense because a plant plant can't like swat you away or eat you unless it's a venous fly trap, I suppose. But they can certainly poison you. And so this is one of the ways they poison you is they basically Well, way back in Bio 101 or Cell Bio, which I forget which, but it was like Professor Drew a circle. Inside the circle is a smiley face, outside the circle is a frown. And inside the circle, the smiley face is homeostasis. And saponin, as a toxin to a living being, is going to ruin your homeostasis by just making you exposed to the outside world in your cells, which is really kind of... Scary, but also like in this sense, it's really cool because it means that we can do experiments on a wall-less house of a muscle fiber. And in order to, oh, by the way, in this paper, they call this the gold standard of mass-specific respiration. I personally do not consider it the gold standard. I mean, who the fuck am I? I'm just a guy on a podcast, but we'll talk about my issue with that in a little bit. So once we have this wall-less house of a muscle fiber, we can add massive amounts of things like ADP and inorganic phosphate and oxygen at super physiological concentrations, and then we can run experiments on mitochondria in situ, as it were. And so this is like kind of in situ VO2 max for your mitochondria, but since we have a bunch of other extra mass around it, and actually the rates themselves even regardless of the mass are lower for the permeabilized muscle fibers than it is for isolated mitochondria which in a way makes sense but also in a way is like how does that happen? You know? Yeah. So in practice What we're actually looking at when we add these ridiculous amounts of O2 and ADP and phosphate, we're looking at the maximal electron transport chain flux capacity. Like what is the absolute max rate that we can make ATP or basically consume oxygen really? That's how we're measuring it in the experiments. How fast is the oxygen dropping down? And I've seen the traces. I've spent way too much time on the Ouroboros YouTube page and reading their manuals and stuff. I swear to God, if I ever went back into bench science, this is the kind of stuff I would love to do. So if you are looking for somebody to be a lab tech with all that stuff, don't call me. I'm way out of practice. So this is actually way faster. When we run these experiments, this is a lot faster than we can have our cells do as living tissue because in our living muscles, oxygen transport and delivery is actually the limiter of ATP synthesis. But when we are looking at these isolated things, the limiter is how much of the total machinery do we have around. So how does this work? Because, right? Because at first, when I first heard of this, I was like, that's curious, why? So when we make ATP, we discharge the proton gradient through complex 5 to create the ATP. And complex 5 spins at a certain Vmax, a certain maximal catalytic rate to create ATP. And this cannot increase just because you've got extra oxygen around, right? because it kind of happens regardless of oxygen. It just has to, you need substrate and it'll just like shoot protons through and just going to drive the motor forward. What we're doing is we're looking at parallel throughput. How do we get more ATP generation from the same mitochondria? More complex five. That's how. So we're in danger now because we're discharging the proton gradient. And if we discharge it enough, the balloon deflates and the cell dies. Well, in our isolated fiber case, we don't care because it's already out of the tissue. But in our body, this is very much a care. So we also need a lot of copies of the electron transport chain proteins around too in order to pump protons to keep the proton gradient normal. And we also need a lot of complexes one and two to strip electron transport, electron transports, sorry, electrons from our reducing equivalents NADH and FADH2. And now we can maintain the proton gradient, but also to keep this up, well, this isn't really a limiter in these experiments so far as I know. We're not really using the Krebs cycle here. This is just like what we're going to give the electron transport chain all the stuff it needs and we're going to let it go hog wild. So, why are we talking about this? I'm sure you're wondering. It turns out, low intensity volume does not have a big effect in this department. It has some, according to this paper, it has some, but it's not massive compared to sprint interval training, which has a very large outsized effect on this specific measure of adaptation. Like, way more than citrate synthase activity. and it's especially when you the paper you know in the last couple figures looks at relative to the total time spent exercising when you look at sprint interval training and this effect of mass specific respiration compared to the other types of to the other lower intensities relative to the amount of time you actually spent exercising you actually get massive benefits here massive and like What kind of volume are we talking about? 8x30 second sprints, 4x30 second sprints, et cetera, et cetera. Those are the kind of typical interval protocols that we're talking about. So why this effect is seen is not entirely clear. The authors have a theory. I have a theory. So the author's theory, and partly they're kind of quoting the authors that they're reviewing too, is that it's related to larger motor unit recruitment. being seen here as an outsized response in the adaptation of the mitochondrial content in larger motor units. And I find this completely plausible. And it might actually be part of the explanation of what's happening here. And this actually, not that I think about it, this actually does have some practical application we'll talk about, but just some. So my personal theory here is actually related to the limitations of the permeabilized fiber model. Hmm, interesting. Yeah, so I think I'll be able to explain this well enough. So due to the isolation and measurement methods, the mitochondrial content increase could be the same as measured by citrate synthase, but in the permeabilized fiber model, the measurement may be biased more towards surface-oriented mitochondria. Interesting. Yeah, I guess that... That makes sense? It's going to make more sense in a second, because here's why I think that. One of the limiters of sprinting, physiologically, one of the reasons that we fatigue, fatigue is multifaceted, so this is just one of the many. It's excitation-contraction coupling energetics. Like, this stuff fatigues. The actual resequestration of the signals between the neuron and the muscle fiber, for instance. This needs training itself. And also, like, we're looking at, you know, a lot of contraction energetics too, like in terms of calcium handling. You know, what happens? We are looking at, like, where are our signals coming from? Like, you know, they're coming from the cell's surface a lot of the time. Because subsarcolemmal, you know, glycogen and mitochondria are totally a thing. Like, this is actually a studied part of physiology. And so if sprint interval training increases the things like glycogen content under the cell surface, for instance, for excitation contraction energetics, you would, of course, increase mitochondrial content there in order to help handle this stuff more aerobically. And so it's totally possible that this subsarcoliminal increase in mitochondria Should It Happen, is actually being biased for because that's the first thing that the oxygen hits once it starts going into a permeabilized muscle fiber. And then that means all the mitochondria on the inside are kind of getting short shrift with the oxygen because it's like all those mitochondria up top are like really kind of going at it. And it's just kind of like, yeah, it kind of sounds like the, you know, when Trees grow in a forest, right? Like the tallest trees that are able to get the sunlight sort of block out, like the canopy creates a like a shield over the smaller trees that are then unable to get as much light to actually function and live and, you know, utilize their chlorophyll. That's a great analogy. Yeah. So there's another possible thing here, which is that with sprint interval training, we are actually getting more hypoxia induced response with SIT. which could increase proteins like myoglobin and help shuttle oxygen further into the permeabilized muscle fiber. All of this is a possibility. I have no evidence. This is all just like a somewhat educated guess. So I could be totally wrong on all this stuff. Anyway, so taking all this stuff together, along with the citrate synthase enzyme assays with the sprint interval training studies, There may be some sort of non-stoichiometric increase, there may be, in the electron transport chain proteins relative to Krebs cycle proteins like citrate synthase. And there's possibly even a cristae density thing going on here. Again, just a guesstimate. But it's possible that the stoichiometry over time returns to normal. Depends on kind of where relative to the training did all these things take place? Did the measurements take place? If you are doing easy endurance training and then you do sprints on top of it and you're doing high volume, like how does this affect it? We don't really know. So it's possible that there's some sort of sub-circle limel activity going on here that's maybe not, who knows? But actually, the kind of practical Takeaway from this section of the paper though is that while there's nothing really actionable we can bank here for training advice, it does show that there are some somewhat specific adaptations to very high intensity training. And I think in a way this shows that you don't get every possible adaptation you want with just low intensity and threshold training or even VO2s. It's interesting that you say that because there was a I was listening to a podcast with Dan Bigham and he was talking about preparing for the pursuit and the kilo and the team pursuit and stuff and yeah I guess after a while and focusing more on road time trials and doing a lot more endurance stuff he came back and was like oh why isn't his pursuit start or his kilo start as fast as it used to be and he was like oh look I spent you know an hour in the last year total doing sprint training. Maybe I should do, maybe I should do, and I'm probably, I'm sure I'm misremembering exactly, but basically he said, yeah, like, you know, even for someone like him who is doing mostly aerobic endurance type efforts that, yeah, that, you know, there isn't a substitute for doing some of that sprint training. Yeah, I mean, I mean, the real, you know, this goes all the way back to some of the original advice from, what do you call it, Andy Coggin, where he said, train for performance and let your physiology sort itself out. And I still agree with that. Because, you know, like I've said in the podcast a billion times, performance is the gold standard for me. Because if you can do all sorts of fancy moves and be like, oh, your lactate's gonna blah, blah, blah. Yeah, but did I get faster? That's all I want. Did I get faster? Did you make somebody faster? Did you make yourself faster? If you did, great. And a lot of the time, if you think it happened for X, Y, Z reason, it maybe didn't happen for the reason you think it did. I'm sure I think a bunch of stupid shit where things aren't happening for the reason I think they are. But I'm always willing to learn and try and change my mind about stuff. And when it comes down to it, somebody says, oh, I'm lacking performance in X. Okay, we're going to work on X. Or the things that I know are going to support X. Like somebody needs more sprint power and they're very slim. Okay, we're going to get you in the gym. You're going to start lifting weights. I want you to put on a couple pounds this fall. This is going to increase your sprint power, right? Right. Okay. Now we know this physical limiter and we're going to work on it. And that's a goal. And everybody's on the same page. Great. Later, sprint power improves. Great. Mission accomplished. And it's that simple. And it's not necessarily like, oh, well, this is going to have a trade-off of this, and this is going to have a problem with this, and I'm going to get out my always sunny, you know, conspiracy theory board, and I'm going to be the guy with the funny hairs going, aliens! Like, it's not like that. It's very, very, very simple. Anyway, so I did kind of like this to get an opportunity to talk about permeabilized muscle fibers as a model. But also at the same time, I did kind of like that this shows that there's a different type of adaptation, sort of. We don't know why it's happening exactly, but it's different. And if you could talk to anybody who's done nothing but threshold training versus somebody who's done nothing but sprint training and be like, hey, try to do what the other person does. You're going to be like, ah, I'm not trained at this. This is kind of hard. Like, yeah. Go figure. So, anyway, so is that, does that all kind of make sense before we jump back into the endurance thing? Yeah, I think so. I think the biggest thing is that, you know, not that you, we don't want to completely disregard, you're not trying to completely disregard sprint interval training here. You're just saying that, you know, it's, it's, not clear. And these studies, you know, and perhaps, you know, in a few years, we'll have more studies and we can revisit this. But right now, just looking at these studies specifically, there isn't a great conclusion that you can come to, you know, other than you can't just do one thing. Yeah. And I don't think we even needed to look at this paper to realize that. Yeah. So anyway, so back to endurance. I think the headline for this, for practical takeaways, before we get into listening to questions, is that all activity for the recruited muscles counts, quote unquote counts. Like continuous contractions are continuous contractions. If we go back to our list of what causes aerobic adaptive signaling, calcium, check, contractions, you know, redox demand through the electronic transport chain, check, like continuous exercise, got it. How hard are you training, AMPK? Check. Like, the list goes on. So I think, in a way, you know, people who, like, somebody asked me this over the weekend on Instagram. Somebody DMed me, or it was one of the AMA questions, said, like, oh, so, like, all the people who commute an hour twice a day, like, we're actually increasing our training volume. I said, yeah, you are. Absolutely. Yeah. Yeah. Yeah. As long as you don't do it so hard that you're, like, wrecked for your workout, don't, like, you know, sprint from every light in traffic, but, yeah. It's interesting, because you think, like, I kind of always thought people, I won't say knew this, but that's, like, kind of a hack, if there is such a thing, just to get, um, to get extra volume in, to sneakily get extra volume in. Yeah. Obviously, people who are there with, I don't know, two-hour bike commutes each way, obviously, they know they're getting in more training. Oh, yeah. But, you know, an extra half an hour a day adds up, right? Yeah, it does. It's not nothing. And I actually find that the less volume somebody has, the more that that commuting volume makes itself known in the fitness. Like if somebody is training 10 hours a week and four out of them, out of those 10 hours are commuting and somebody stops commuting and we're down to six, there's a noticeable impact on their fitness. I mean, that's almost 50%. Yeah. Yeah, exactly. That's a lot. Yeah. And so that's one of those things where it's like, if we can get it back, I'd like to, but sometimes it's not possible. And I remember when in the pandemic, when things closed down, I had a client who was commuting an hour each way on an e-bike. And as soon as lockdown happened, he started working from home and he was no longer commuting. We lost like, what, 10 or 20 watts from his FTP and we never got it back. Yikes. I mean, also, there was possibly a lot of stress going on with the pandemic and all. Weird. Yeah, weird that a physician might be stressed during a global pandemic. So that might have been part of it, too. Who knows? I don't. But anyway, so the other couple conclusions that we can make here is that FTP, while recruiting more muscle mass and If it's not selection bias by just having more of that kind of like middle 60 to 80% of WMAX kind of papers here in this study, then the FTP intensity, like sweet spot, tempo-ish, might be the best explanation for why we see the studies with the greatest full change of citrate synthase activity. Because it's a combination of not only volume, like high volume, but higher Kind of intensity at like 60 to or 70 to 80% of WMAX, you know, that's basically threshold training for a lot of folks. And if you are doing that much of it, I mean, if you can physically do that much of it, like it's going to have an impact on larger motor unit recruitment. So that might be, because remember, this is, these synthase assays are from, what do I have been calling it? Muscle margaritas. Don't drink that. Like a meat shake. Yeah. So we're not specifically looking at the motor units that got the stimulus, necessarily. We're looking at all of the motor units. So that could be part of it. But again, like refer to our previous discussion. So I also feel like that this paper supports what I've been suggesting as best practices. and also other people like Seiler, you know, ride as easy as feels good basically and pepper in the intervals, make sure they're high quality intervals, make sure they're progressing the way you want them to. Like this is super, super basic stuff and as soon as somebody says, you know, what percentage of FTP should I ride at? Like, you know, where's your LT1? Feel that out and then we'll talk about it. Most of my very experienced clients who have very high LT1s, like we're talking like, I can name a couple guys, Threshold, Low 400s. LT1, like 350, 360 watts. Where do they spend all their time riding? Between 200 and 280 watts. It's also like when people ask you how easy should you go between your, say, FTP, your sweet spot intervals, you're like, and, you know, and people make this assumption that they're like, oh, maybe if I sneak in, you know, make it like zone three in between these zone four intervals, like, no, dude, just, just. Paddle around easy. Like, who cares? Yeah, just don't lose your warmup. That's all. If you've got an hour between efforts, you don't need to, like, spin at 50 watts. But if you've got five minutes, yeah, spin at 50 watts if that's how you feel like you're going to have the next best interval. Yeah. Yeah. And so, very practically speaking, and we're going to get into this a lot more in the next 10-minute tips, is this all comes down to fatigue management, if I'm going to put my coaching hat on for a second. If you're tired from pushing your endurance too hard, then your intervals are going to suck ass and not be nearly as effective, if they're effective at all. And nobody wants ass-sucking intervals. You want good, high-quality intervals. Or, as some coaches I know would call this kind of training, triathlon training, where you're always at race pace. This being... Sorry, triathletes. I know the ones listening here. You're all good folks, but I know you know people who do this, and so do I. So, all this stuff says that, well, actually, to keep my coaching hat on for a second, as you become very well trained, you know, if you're riding a, well, if your LT1 is 350 watts, right? And you've got an eight-hour ride, you're not going to do it at 350 watts? Are you kidding me? Like, how much energy is that? It's a lot. And you could technically do it. Yeah, it's great. It's great on race day where if you're at 350 watts and you're like, I could literally do this all day. It's fine. But this is what I call a kilojoule burden because this becomes about, we're not talking about fatigue management. Now we're talking about energy management is what I call it. And so I call this also a kilojoule burden. Because if you burn enough energy on top of your basal needs and your daily activity expenditure, well, if you're riding eight hours, not going to have a lot of activity besides that, but you would be very burdened by the duty to replace the lost energy. And it can take days to get it back to baseline, especially if you've got an eight-hour ride with like hard intervals. It becomes very, very difficult to catch up with this stuff. So that's all the practical stuff, and we'll get into a lot more of that, like I said, but I guess my last note here is that actually if we control for the same intensity, then for the same intensity, we can say that duration matters the most. So if somebody's going to ride at 50% FTP, regardless of where that is for LT1, if somebody's doing four hours and somebody's doing six, the person doing six hours is going to get better adaptations than the person doing four, like just because it's more. More is more. More is more. Sometimes more is more. So going back to our questions from the start, how hard is too hard? Depends on what you want to get out of it. So if you're doing FTP intervals, do FTP. It's cool. If you're doing endurance riding, it's, to me, it's an afterthought. I tell people, pedal at an intensity that feels good. And actually, one of the things, is that the RPE decoupling is very weird. And this is something we'll get into in the next episode again. But when it comes to how easy is too easy, like I've got clients where, you know, we'll start working together. And the first thing I'll say is like, go out and I want you to ride at a pace that feels all day pace. And like, you know, pace drops off, somebody's a little fatigued. I'm like, okay, give me, give me 20 or 30 watts easier. So if somebody's got a 300 watt FTP and they go out and they do that ride at 220 watts, let's say. and they put down like a 5 or a 4. Okay, cool. Is there a LTE one that high? I doubt it. So, what do I do? Give me 180 watts. 180 watts. Okay, this one comes back at a 2 RPE. They're like, I barely felt like I was doing anything. I'm like, good. This is very good. Like, I smile so big when I see something like that because we drop, what, 40 watts? and we dropped the RPE significantly and that it's a weird decoupling of RPE because a long time ago I said like, well, like a four to five out of 10 RPE. What I didn't realize at the time was that's my personal scale. Endurance pace for me is like a four, four to a five. For a lot of people, especially as you get better trained, two, maybe a three. And so I've learned to meet people at their RPE scales rather than dictating mine to them. And, you know, it's a kind of a language, common language between a coach and an athlete. And so, when we look at that, now I know, okay, I got to give this person a two to a three for, you know, an eight-hour ride. Give me two to a three RPE. Fuel well. Have fun. That's it. Yeah. Nothing else. Stop if you need to, you know. Don't worry about... Oh no, it's not too long for food and now my eight hour ride is technically two four hour rides split up. Yeah, yeah, no, yeah, it all comes out in the wash and all, I mean, this is where I just look at how many hours a week. It's a really simple measurement. Is it perfect? No, absolutely not. But is it close enough? Yeah, yeah, it is. And so the last question, how much is enough? If you got more time, I mean. If you're looking for endurance performance, yeah, you can ride more until you get to fatigue management and energy management. That's realistically the limit. Of course, most people have jobs and families and things that are way more important than riding a bike, in which case, you do what you can and don't worry about it and take care of your family obligations, take care of your job obligations, be a good person, be a good human and riding a bike is for fun. But, you know, if you're a professional, Yeah, there's, feel free to, feel free to do more. It's only going to help you until you get to the point of fatigue management and energy management. The intensity, you know, forget the intensity. Forget, oh, I did it only at 45% FTP. That's great. That's great. Have fun. Especially if your LT1 is like 55% of FTP, 45% is great in my book. So any other thoughts before we dig into listening to questions? No, I think it makes sense. I think the biggest thing here is that, you know, it's maybe like a not particularly exciting conclusion that you just came to. So many of these podcasts are just letdowns. I'm so sorry, everybody. But I think it is good and bad, right? Every few years, months, decades, whatever, various things come back. some popularity with training fads and what's in and what's trendy and all this stuff, but it's kind of predictable, I guess, and maybe good to see that some of these tried and true things still work or were true, and like you said, maybe not, they're true for maybe not the reasons that people thought, but old wisdom about, you know, riding a lot in the little ring is maybe not wrong, but it's just not correct for the reasons that whatever some stupid website says it's correct. And at least know that you don't have to nail it, like, super perfectly, like you said, and, like, I think people can give themselves a lot of extra stress, mental stress, if they're worried that, oh, this workout wasn't an A+. that they need to have A-plus nailed workouts every day or it's just going to be ruined. Yeah. Every time you work out, it has to be an A-plus. It doesn't have to be an A-plus. And you don't have to nail it exactly to four decimal points or something. Can you even measure four decimal points in watts? You can barely measure a watt accurately on our power meters. Right, exactly, yeah. So even, you know, let alone that, right? But just that you didn't, oh, you know, I don't know. Yeah, you went out of zone two. Oh, no. Yeah, exactly. Or like, yeah, oh, you had to get over some hill and you couldn't do it in zone two. Like, yeah, it's fine. Like, don't worry about it, you know? Yeah, and this is where I tell people, like, I want people to pull back and use more qualitative assessments of the ride intensity. Did you get home feeling like about the same as when you went out? If it's a three-hour endurance ride, you should pretty much feel about the same, which is great. Okay, yeah, well, you do exercise? Yeah, sure. You ate some stuff on the bike? Yeah, okay. You need a little extra food? You're a little hungry? Yeah, sure. But, like, you didn't get home smashed and, like, crawling to your couch and going, I could barely unclip. Like, that's not a good endurance ride. So, and also, you know, the practical sense, fatigue management, you've got to just make sure that your good quality interval training days are good quality. You know, that's that. And otherwise, you know, the intensity is kind of an afterthought. Do your intervals well? Do your endurance riding easy? Like, don't fuck with your recovery days? And you're going to be fine. First question. Just jump right in. Classic one. 10 hours of zone 2 or 10 hours, sorry, 20 hours of zone 2 or 10 hours of sweet spot? LOL. Okay, well, I mean, well, what's the most amount of sweet spot a reasonable person would do in a week? Like, let's say it's two sessions, and somebody's really amazing, got a big diesel, like, what could they do? Probably two to three hours of sweet spot? Okay, we're gonna go ridiculous. Let's say three hours. All right, six hours a week. So, ten hours, ten hours a week of sweet spot, if you work out, if you ride six, six days a week, right? That's an hour and 40 minutes a day. So that's five by 20 a day. Five by 20, six days in a row of sweet spot. Like, oh my God. Yeah. Yeah. Okay. Okay. Practically speaking, fatigue management is not happening if you're doing 10 hours a week of sweet spot. So here's the thing. This is kind of a preview of the next episode. Think about your hard intervals first. Think about the quality of intervals. Think about progressing them in the way that they need to be progressed. And then once you've kind of reached the limit on how many of those you can do in a week, and that varies, of course, based on stress and recovery and all that stuff. Once you've figured that out and you figure out how many recovery days you need, you can backfill the rest with easy riding. Because even with those interval days, Training still counts as training. And it's slightly higher intensity, sure, you get slightly higher fold change of citrate synthase, you know, on average, potentially, sure, for the intervals. But like, for everything else, it doesn't matter. And this is one of the reasons that when I'm looking at, you know, building fatigue resistance with somebody, one of the first things I look at is how many hours a week have they been riding on average for the last like year or two. And if it's... Pretty low, most people it's pretty low and if they got time to ride more, yeah, cool, we ride more. Anyway, so that's the right way to balance. But no one's doing 10 hours of sweet spot. Yeah, please don't, oh God. Oh, next question is, of course, can you ride endurance too easy or do you just have to ride longer? You know, for a practical, in a practical sense, if you're LT1, let's say is like 70% of your FTP and you've got two hours to ride, but you could easily ride for five without feeling it. You're like, you know, I'm going to ride a little high today, but it's still going to feel easy under that LT1 kind of RPE decoupling. That's fine. But you don't need to. You really don't. So this is, again, a question of fatigue management. Just make sure that your easy rides aren't too hard, I guess. So, yeah, and again, LT1 is that first threshold occurs at wide range for people. Like for me right now, it's like 50% of my FTP. And if I ride right at it for six hours a week, I can feel the fatigue. I really can, which is kind of sounds stupid, and that's how badly trained I am, but that's okay, because that's where I'm at, and I don't pass judgment on me, and I don't pass judgment on other people. So if that's you too, then if I were your coach, that would be fine in my book. 

A lot of equivalence questions. And you're getting what you want out of it, right? Yeah, it's exactly what I'm trying to be. Well, yeah, it's like at this point, I'm old and injured enough that I no longer train. I exercise. A lot of equivalence questions. We're going to skip these. Oh, actually, these different people asking basically the same question. I wonder if they all saw something on a forum or a podcast somewhere. Okay, that's off topic. Let's see. I get faster with higher intensity plans at half the volume of a quote-unquote high volume zone 2 plan. Is this normal? Yeah, this actually comes down to kind of what we said about you don't always get the same adaptations. You don't get the whole suite of adaptations you want and all the muscle fibers you want by just riding easy endurance. Like, I don't know if anybody has ever said that's a good idea. I don't think I've ever heard it but I think it's I don't know Kyle do you think it's easy for people to like just read that and conclude that like oh I should do zone training zone 2 training so therefore I should ride like all my my next three months will all be 15 hours a week of zone 2 I'm sure that's an easy conclusion to make I think a lot of people I think a lot of people will try things if like that maybe not go completely whole hog where they're like I'm only gonna do zone 2 But I think if you're just going to try it, that could be a natural sort of easy, I won't say mistake to make, but just like the first thing, what's the easiest, sort of simplest, most straightforward thing you could do is just do a bunch of endurance rides, you know? Just like squeeze them in as I can and just all endurance rides. Yeah, so like So here's the thing. It's like if you feel more fit, like doing intervals, yeah, do intervals. It's that simple. And I would say at some points of the year, it's better to just write easy. But at some points of the year, you absolutely have to like start increasing it because here's the other thing is that doing the same thing all the time gets stale. And the adaptations you get kind of... Start to Plateau, like, because you can't increase volume forever. Like, there is a limit for volume. And some people have reached it, and that's fine. And if they could recover better, they could ride more and be in more fit. That'd be cool. But realistically, it's not going to happen. So you've got to kind of think about it holistically. And, you know, especially if you're racing, you know, train for your racing. and everything else is going to sort itself out. So no need to overthink it too much. Let's see. How low is too low in terms of an IF for an endurance ride? Yeah, so like I said, LT1 happens at a different place for a lot of people. So find that. And here's my quick guide on finding it. Start at like 40% of FTP. This should be under LT1 for most people. Start there and ride for 20 or 30 minutes. This should feel eminently doable. Then go up to 50% of FTP. For most people, but for some, it'll be like, okay, this is getting tough, but I could do it for sure. And then you start bumping it up until you feel that RPE decoupling. You may at this point start to get cardiac drift. You may get it below depending on how well trained you are or how your muscle fiber type or how hydrated, et cetera, et cetera. So cardiac drift is not a great indicator. You can use it to start to triangulate, but it's not perfectly reliable. And so, yeah, so try to find it. Try to find that kind of threshold and ride under that threshold. It's that simple. regardless of where it is relative to your FTP. I think that's an easy mistake to make and I think a lot of people make it and a lot of people want that kind of marker but it's also the same as like what percentage of FTP should I do my VO2 max at? I can do them at 140 to 150% for like three to five minutes. Like what about you? 110%? Cool. We're different. All right. So you've got to individualize this stuff. Yeah. And some of that just comes from Being more experienced and riding more and just knowing how you react to different intensity domains. Yeah. Yeah. Because, you know, that kind of stuff can be very individual. Like, I coach a handful of people who kind of feel sluggish after they start training again after the offseason until I start giving them, like, a couple sprints. and like anaerobic capacity stuff. Then they go, oh, now I'm feeling switched on. Now I feel good. Like that's not everybody, but it's a handful of people. In which case, I'm going to try to pepper those in occasionally to keep somebody feeling good, but without adding undue fatigue. And yeah, so everybody's different. And that's okay. I don't judge anybody for it, like I said. Is an endurance ride bookended with intensity a good way to improve fatigue resistance? Yes, actually, you don't have to even bookend it. You can kind of pepper that intensity throughout if you want. Yeah, we've talked about that before, right? Yeah. Do like a three-hour ride and every hour do some sweet spot. Yeah. Oh my God, that must have been like five years ago now, four or five years ago we talked about that. So yeah, like that was one of my recommendations for FTP training. I believe that was that episode. Like I said, it's been a long time, but that is still a way that I assign FTP training is I'll give somebody like five hours and, you know, give me... 20 minutes of, uh, 20 minutes FTP, um, you know, on the turn of each hour, between hours one and two, three, four, and five, and four and five, like, yeah, give me 20 minutes of FTP around that, doesn't have to be perfect, obviously, um, and that's a good way to do it too, but, you know, especially if you feel like you need work, uh, mentally pushing later on, like, you can bookend it for sure, there's, there's, short answer is there's no wrong way to do this necessarily, find a way that you feel is enjoyable. and you are seeing improvements. So like if you do a five minute max effort in hour one, then you do one in hour two, three, four, five. What happens? Most people, we're going to fade over those efforts. If you have good fatigue resistance, what are you going to drop? 10 watts, maybe 20. Somebody like me, I would probably drop all the watts. I'm kidding. Yeah, like 100. 50, 100. I would basically be doing like barely above FTP for my last effort after five hours right now. That's how bad my endurance is. But again, I'm riding like six hours a week. So why would it be good? And I'm not naturally talented at this at all, whereas some people are highly talented. So again, it's like wide range of abilities. But yeah, so yeah, pick a ride that you can track your improvements on and just have fun with it for sure. Am I losing endurance by riding three hours 30 instead of four hours if going slightly harder and the kilojoules are equivalent? Yeah, don't think about this by kilojoules. Like, I mean, think about how much you need to eat by kilojoules approximately. It's not a perfect number, but you can go by it. And if you go from four hours where it's like under LT1 and three and a half where it's a little over LT1, you're adding a little extra fatigue. You don't necessarily need to. So, and here's the thing is like with my clients, if they've got 3 hours, normally they do 6 for endurance riding. I would expect them to do about the same watts for 3 as for 6. That's it. I'm not like, hey, give me another 20 watts because you're going shorter. No. Slicing the salami pretty thin. That's a phrase for you. That might help with permeabilized muscle fibers too. Actually, that's how Krebs did his early experiments. Actually, a lot of his experiments. They, um, they, uh, sorry, kidneys, liver, take your pick. Um, no, really, they, what they would do was, um, sorry for the animal lovers out there, uh, they would, uh, sacrifice an animal and take the organ out and slice it super, super, super paper thin. and then put it in solution. And it was thin enough that it was basically kind of permeabilized in a way. And so that's how they did a lot of their experiments to find the Krebs cycle, but also, especially before that, that's how Warburg was working and that's how Krebs discovered the urea cycle. So if you read his biography, I haven't read volume two yet, but I've read volume one. the, uh, um, the one by Ames, oh, Holmes, not Ames, um, it really goes into detail on the biochem, so if you're into that kind of stuff, highly recommended. Let's see, um, quote-unquote, muscular endurance is just volume at relevant intensity, change my mind, um, no, I will not, because I, I agree, like, this is the thing about, Training for Racing the Way We Do. If you are doing 20-minute climbs and all you're doing is like, or if you're doing criteriums and all you're doing is easy endurance riding and you jump into a criterium, you're like, wow, I suck at accelerating. It's like, yeah, you haven't trained it. Weird. Yeah. Sorry. Just like Dan Bigham found. Yeah. He fucked around and he found out. So. Yeah. I think the biggest thing is like. that comes with that like phrases like muscular endurance too is like everyone has their own weird terminology and stuff like that so I think sometimes when people say things like muscular endurance it's not exactly clear what they mean um mitochondrial function yeah so that's another thing I think where questions like this come up it's like we need a we need a better you know universal glossary of terms or whatever yeah I completely agree Let's see. Unless you're trying to sell someone something and then you want to pepper in all those little fancy buzzwords. Fancy buzzwords and your own proprietary terminology complete with, oh, never mind. Is volume more important than sustaining the same watts because variable waves are easier? Yeah, I agree. And it's definitely total exposure to exercise, we could call it. I think that's what David Bishop called it anyway. Total Exposure to Exercise is, to me, for the same muscle group. Because if you're swimming and you're using your arms, this does not count towards cycling. But if you're running, this counts a lot more towards cycling because you're using your legs, right? So to me, total exercise volume on the same muscle groups is what counts the most. I literally look at it in terms of total volume. And I include recovery rides in that. Total number of contractions really is your... Yeah, but now I'm sure somebody's got a big brain about their contractions. What do you want to bet? It's those wires. Let's bet the next listener donation. But we have to spend it on Chipotle. Okay. No, it's the, um, it's those, the, the muscle contractions things, the way the big brain is at is sit on the couch and use one of those EMG stimulator things. So you get a lot of contractions while you're eating donuts on the couch. Oh, God. Uh, well, they've done experiments on that with mice for, I don't know. Yeah, I think, I think for 24 hours. Yeah, we did. Yeah, because, because they're not really exercising. Um, it's just, anyway. So, next question is, Thoughts on Poki UAE switching coaches because of Inigo's over-focus on endurance volume? I actually have heard, I don't know how he coaches, I have no idea. I actually have heard, this is Hearsay, so actually, is this Hearsay? I've been told I don't know what Hearsay is. I heard somebody say it. Is that Hearsay? So, it depends when you're talking about it. Oh god, the lawyer answer, it depends. In a legal context. Okay, so this is not legal context. So I heard somebody say that Sam Milan has actually not coached Pogacar for years. I don't know this to be true. I have no fucking clue. But I don't know. So yeah, so this is like cycling super inside baseball. Honestly, I don't really care. I know his new coach. He's a good dude. I like Javier. I think Javier likes me. We've worked on a couple projects together. He's a good dude. He's a good coach. I mean, from what I've seen anyway. So, yeah. So, all power to Javier. Good job on getting Pagachar. I would pay to coach Tadej Pagachar. I couldn't afford it, but. Yeah. Just to see the data, just seeing the data, right? That's always the thing is that cycling that says now is even more so than ever is such a data-driven venture that just to see some of it and to know like what's real, what's possible is pretty cool. Yeah. Yeah. So I have no thoughts on this question whatsoever. Is it possible to gain fitness on low hours like sub 10 or is it to just maintain? Yeah. Well, for muscular endurance, for sure, because you can only do so many threshold intervals and you can only do so much total volume. You know, you will plateau with the endurance stuff. And the same goes for, for most people, the same goes for higher intensity and building VO2 max. But for a rare handful of people, it seems like they can still do 10 or 15 hours and keep building it up until they reach their actual true genetic max. But this to me is not the norm. This is a very, very rare exception. So yeah, like Tim said, when he was on the podcast, Tim Cusick. He said that most people reach their training max. And I think most people, the huge majority who are riding about 10 hours a week do reach their training max at some point, but there's always different stuff to tweak. And of course, if this is you, you can totally change your approach to a season. You can be like, oh, well, if this is about as fit as I'm going to get, well, maybe I get to start to work on my sprint or maybe I get to work on... Maybe I get to be more fresh for races if this is about the level of fitness that I'm just doomed to have. And that can actually work advantageously for you too. Imagine being more fit at more of your races. Like, how cool would that be? Instead of like peaking for like three. Is there a difference between a five-hour ride and two, two and a half hour rides over two days if I'm time crunched? You know, in a way from the big picture, It doesn't seem to make a big difference, but this is something that where we could see a small difference if we really dug into the individual variation on this and these people ride two and a half hours or let's make it easy. These people ride two hours for three days a week and these people ride three hours for two days a week and this group rides six hours for one day a week. What's the difference there? I don't know if that's been done. But what I do know is I'd like to see it. So the realistic thing here, and this is the advice I give to everybody, including my own clients, is let's do whatever is least stressful for you. Because the, and this I am absolutely certain about, the impact of the stress you get from like having to shuffle your life around is greater than the impact of the difference between two, two and a half hour rides and one five hour ride. Yeah, I would say my first reaction to that is the only reason that it would be a really big potential hindrance is if you were originally scheduled to have like a day off off and then now you've just tacked on extra volume and that makes you not as recovered for say a harder workout the next day or something like that. Yeah. That's when splitting it up like that maybe isn't the best. Yeah, or also, if you've got a workout that takes more than two and a half hours, like if you're really working on your fatigue resistance for like gravel racing, you're like, I need to do five hours with like five by 20 minute sweet spot efforts. Like, I mean, that's not a bad gravel workout. Should that be your only gravel workout? No, but it's not a bad one, like for race specificity and whatnot. So, in which case, you can shuffle that around to do that every two weeks or something like that, if that's a little more stressful, but... That's a good specific thing. So there's a balance point and you've got to find that for yourself. What the hell? Kyle, maybe you've heard of this. Does intermittent squatting or lifting during a ride improve muscular endurance? Renato Canova style work. Who is that? I don't know that one. Oh, interesting. No, I don't know. Shout out to Jeremy, by the way. This dude asks so many, like, really interesting, like, oh, I've never heard of, I wonder, kind of questions. So, shout out to him. And he's asked several, but they've been a little bit, they've been a little bit, a little bit off topic, or a little too tangential for our purposes. Google says this guy's a marathon coach. Interesting. Kind of old guy. I'm born in 1944. Oh, so with running, actually, well, strength training has pretty well been shown to increase, is it running efficiency or economy? I think it's economy. So maybe there's something about that, but genuinely, I have no fucking clue. For cycling, I would hate to ride back to my squat rack over the course of a long ride. I know there are track sprinters who like to do the potentiation stuff, lift something kind of heavy, then go do sprints. If that works for you personally, that's the way I would use it. But yeah, for muscular endurance, I probably would rather do a high quality strength session instead of kind of mixing the two into a muscular endurance margarita. As it were. And then you're, then also you're what, you're restricted to only doing like a 30 minute like lollipop loop so you can come back to your squat rack every hour or something? I don't know, that's just weird. Oh, that's an interesting one. If you do a block of only endurance, is there a better stimulus from slightly higher watts? You know, given that You know, a volume block is probably going to be 15, 20 hours a week for most people, or even like a week where you get a week off of work and you're like, I'm going to ride as much as I want, 25 hours, let's do it. The difference between like the 20 watt difference or even 30, if you're pushing it versus not pushing it, is going to lead to so much more fatigue. And realistically, you don't want to get back from one of those blocks smashed. You want to get out of that block feeling really good and ready to rip your pedals off. That's a fatigue management thing. So that's where I would go with that. Yeah, yeah, I agree. Like, sounds a good plan. Yeah. Does duration trump frequency given a fixed total volume of, say, 20 hours a week of endurance? In my experience, it does not. I know a lot of people, this is not how I prefer to ride or to schedule stuff, but I know a lot of people who do three to four hour workouts more frequently because I'd rather give somebody less frequent, like, six plus hour workouts. It seems to not make a big difference, realistically. So if you've got certain goals where one is a little more specific or more practical, I would say, for your life, then I would go with the one that's more practical. Let's see. Oh, here we go. Total contraction. Wait, who owes who the... the next donation for Chipotle. If totals contraction matter, can I do a six-hour ride in three hours by doing 200 RPM? No, we talked about this too, right, where it's also like some combination of contractions plus contraction intensity where like your average force per contraction in your 200 RPM endurance ride there is Not particularly high. Oh, and your, and your, um, your, what do you call it, the contractile energetics about just contracting your muscle repeatedly that fast, like, that gets very highly taxed. I mean, not, there's not a lot of people who can ride for over an hour at, like, 120 RPM. Um, but in theory, here's one of the other things that happens, this is getting into the nerdy weeds again, but it's Wattstock, so let's do it. 

There is, what's, I forget who, Jim, Jim, who's the, who's the biomechanist, Jim What's-His-Nuts, calls it a, I always forget his name, I'm so sorry, Dr. What's-Your-Nuts, but it's, he calls it a duty cycle, and, yeah, so the duty cycle at higher, even if we assume the same muscle mass recruitment, The duty cycle is shorter with the faster contractions, with the higher cadence. And so your total time exposed to the contraction is shorter, right? And so over time, it all comes out in the wash. You spent the same amount of time under contraction. It's not the amount of contractions. It's also the length of the contractions because what happens when we contract our muscles? We actually occlude the muscle due to the contraction, right? And this is one of the reasons that strength-trained athletes get thicker heart walls because of the peripheral resistance from all the occlusion of tightening your entire body under a heavy lift. And so when we occlude our muscles, we are actually cutting off the oxygen supply real quick. And so if we do this faster, cool, like that's okay. But like in the end, we are getting about the same amount of time with calcium in the muscles and the same amount of time of the electron transport chain being active and the redox signaling happening. So, you know, and at higher intensities, the same thing happens at like FTP. And so now the question is like, if we're getting into bigger motor units, you know, like what would I say about that? I would say then. Do more power, ride harder, do like 15-15s or something like that if you want to get into big motor units. Because one of the other things about doing super low cadence sometimes is that there's a lot of fatigue. And so I know some people are having good success with that stuff. I have not personally found it that useful. Might also just be the nature of like, what are we training versus what are they training? So it all kind of seems to be the same in the end. So yeah, when you big brain the muscle contraction thing, at first it's like oh I can get more contractions but at the same time it's like the total time under tension you could say I think actually Jeremy asked me this question earlier and I skipped over it sorry Jeremy but yeah like the time under tension let's say like you would think about for lifting would be approximately equivalent or the time spent showing your muscles I am exercising would be approximately equivalent the duty cycle time is the equivalent the what have we been calling it the time the area under the curve of contractions would be basically equivalent to. So does that all make sense? And who owes who this money? I want Chipotle. Next donation comes in. Kyle and I will figure it out later. But is 100% being earmarked for burritos. Let's see. You've mentioned the benefits of long rides, six or eight hours. What am I missing? If the most time I have is four hours, you are missing getting divorced. You're missing about four hours. Yeah, you're missing four hours, but you're going to keep your spouse. Yeah. So you also get to, you know, have other hobbies or something. Yeah. A life. You can read books. You can. Yeah. And still eight hours. Like you're like, man, I got to eating after this is going to be an actual chore. and then you get your rest day the next day you're like I gotta block out five hours today just stuff my face everyone's hit that limit though when you're like you've done just a little bit too much that week or something and you like go into work and you're just like I am a shell I am an empty husk of a human very true yeah Here's a good one. Should I add volume after doing my intervals or should I ride longer before starting them? This is actually in the big scheme of things to me it's irrelevant. I would say first do what's more practical for you because if you got to like ride two hours to your interval area and then do your intervals and ride back like that's fine um or if you want to bookend your rides with them that's fine if you want to spread them evenly throughout that's fine if one thing seems more specific to your event or if something you want to just work on that's fine too so yeah or if like if you dread them or something being at the end and you're just like gotta get them over with and then just keep going great yeah what sort of weekly volume do you want to see for cat one riders and what does it depend on It depends on how much time do they have. That's it. Nothing else. How many times, Kyle, I'm sure you've heard this as much as I have, where somebody says, oh, this guy I know, he only rides 10 hours and he's way faster than me. Yeah, I... Congrats, that guy hit a bigger number on the genetic lottery than you did, I guess. Or he's got a better training history, or he's naturally gifted, or who knows? I don't... No need to compare yourself with him. or her or whoever. It's too hard like in a vacuum. Yeah, who can even breathe in a vacuum? Jeez. Want to know if higher volume training has worked? What's the minimum session length if you're well trained? Minimum session length is just like what's most practical or just what's fun for you? Because I've got people who all give them six hour rides and they'll do eight because they want to ride more. And at a certain point, I gotta write them in, but for the most part, that's fine, as long as, you know, all the training is progressing as expected. But, to know higher volume training has worked, you still have to try to measure your fatigue resistance in some way. And so there's a lot of ways to measure this. The easy way to do it would be to like, a simple way to do it that anybody could get a nice objective number from without getting into the nerdy analytics and that all has biases built in too, is go do some max efforts, like once an hour for like four hours or whatever your long ride is. And when your last interval is basically equivalent to your first interval or watching that improve, your fatigue resistance is improving. Congratulations. That's an easy way to do it. You did it. Yay. Yeah. Or like in a race, in a race, you get to the end where the, you know, if you've got like a 1500 watt sprint. Cool. And then you get to the end of a race and you're like barely cracking a thousand. You're like, I mean, I can't even hit four digits. Like it's not that your sprint needs improvement. It's that your fatigue resistance needs improvement. So especially for most people in a race, when you can hit good numbers at the end of a race, that's a really good sign. But that doesn't mean that you can race like an asshole. You've still got to manage your energy because nobody's got infinite watts. Like not even Wout can do this. Yeah. And also, I mean, Vanderpool only doing six races this spring? You kidding me? Smart man. Very smart man. Managing energy. Yeah. Yeah. Let's see. On the other hand, Capecchi is doing like every race. I mean, look, some people are just overachievers. And I don't fault them for that. At the same time, like if you're, if you're Capecchi's management or you're the team manager and you're going, man, she can win like every race she enters, how many races do you want her to enter? What's, what's the question that you ask? The question I would ask is how many races can she enter before she's absolutely fucked sideways from fatigue and doesn't want to look at a bike ever again? Let's do one less race than that. Okay, what if we want her to not be depressed about looking at a bike? Okay, let's go like 10 races less than that. So she might end up racing frequently, but also she may enjoy racing more frequently, or if she's choosing her own race schedule or working on it with management, she's going to be like, I want to race more because maybe she feels more fit when she races more. I know a lot of people like that. I personally, when I was racing, I preferred to race more. I wanted to hit the weekly training crit because I felt like I was more fit. by doing that. And so there's a lot of stuff in here where, you know, we don't really know the answer. Yeah, and I want her to be fresh for this Paris Olympic Omnium battle. Oh, God, yeah. Actually, you know who was fucked sideways from fatigue is Vanderpoel that year that he decided to try to climb every hill hard in the Giro. and he did altitude or he went from the Giro to altitude camp then he had like five days and then he started the tour or something like that like some ridiculous thing where it's like I don't think he thought that one through very well before he did it. Yeah. No, but the Paris road race course is like not particularly climbing, it's kind of punchy and you're sort of, you know, not ever doing You know, obviously there's no long, long climbs. So yeah, punchy classics, reduced bunch sprint. Seems pretty likely. Yeah, I mean, we're talking Vanderpoel, Wout, Kopecky, Voss. Voss, there we go. Now I'm interested in this battle. Let's do it. Anyway, so fanboying out here on pro racing. Question, why is endurance volume, sorry, we're almost done, we got like a couple questions left. Why is endurance volume cumulative in a week but not threshold and sweet spot? I would say it is. It is, yeah. Yeah. I actually think about total volume and interval time as somewhat separate variables. Like if somebody can do 20 hours a week but they're kind of tired and like just riding easy is going to be better for them, I don't even think about interval volume. But, you know, if we're looking at interval volume, I think about how many hard days. And the fatigue that you accumulate from doing intervals is non-zero. It's far from non-zero. And so, yeah, so I don't really necessarily think about accumulating time there. I don't think about like sweet spot total volume for a week. I think about how many hard days have we done and are we trying to progress time here or are we just looking to maintain time here? And I want to know the difference. The time of year and somebody's feedback will kind of dictate that. Let's see. We're going to skip that one. Sorry, sir. Are there useful hard workouts in 30 minutes or should that always be a recovery ride? I think we know the answer to this. 

I mean, you can do Tabatas in 30 minutes, but yeah, you can do 30 second effort sprint interval training. But I mean, honestly, yeah, you could do a quality workout in 30 minutes if you are ready to smash yourself silly or if you're just looking to maintain. Yeah, like you can do just kind of a maintenance dose, like just do a 20 minute. No, yeah, one by one by 20 minute, like warm up for 10 minutes or, you know. 15, do a 15-minute interval, do like a couple minutes cool down, don't go right from smashing yourself to not, yeah, spin the legs out, but yeah, like if you can, if you can do, like depending on your goals, yeah, you can do a workout in 30 minutes, but if you're like, man, I'm really progressing time and zone for threshold and I'm at 3x15 next time I'm doing 3x17 or something and I can't do that in 30 minutes, of course you can't. So, yeah, just spin easy and just wait for the day where you've got more ride time. Yeah, it's that simple. Hmm. Okay, last question. This is a good one. Within each intensity domain is the total dose, basically duration times intensity. Well, that is exactly how this paper broke it out. So, in a way, yes, but... As we saw, the intensity kind of doesn't matter until it does. So like I said, you've got your total volume, you've got your interval training, and you've got fatigue management and energy management. And practically speaking to me, at least that's kind of what it all comes down to. So to each intensity domain, I don't really think about them as separate things. Like I said, I think about total volume. I think about progressing intervals and I think about managing fatigue and working on some of these weaknesses if we need to, race considerations, that kind of stuff. So it's all basically basic coaching stuff. So yeah, we don't really need to big brain this stuff, even though it's tempting. So I think we're all set for today. Yeah, sounds good. It's been a long one, but you know, people sometimes like that. There are those diehard fans out there. Yeah. We appreciate everybody. If you made it to this point, I'm going to buy you Chipotle. How's that? Five years. Made it. Yeah. Thanks everybody for sticking around for five years and I really appreciate it. And yeah, we got a lot more stuff coming out. Thanks everybody for sticking around, especially for the last couple of weeks where I didn't put out a podcast. I was so busy. But yeah, here we are. So if you would like to sign up for coaching with us, empiricalcycling at gmail.com. If you want to consult with us too, we will answer all of your questions. We can help you look at your training and help you analyze whatever, help you periodize your year. Our time is your time. Anything you want to talk about, we're here. So, uh, purplecycling at gmail.com for all of that. If you are sharing the podcast, giving it a nice five-star rating and a nice review. We've had some really nice reviews lately, by the way. I just looked for the first time in about a year and boy, you, we have great listeners. Thank you all. You are all fantastic. Thanks so much. if you want to donate to the show because we're ad-free empiricalcycling.com slash donate and if you want to check out the weekend AMAs or ask a question for the podcast follow me over on Instagram at empiricalcycling and we will see you all next time I hope my voice recovers sounds good see you everyone