Welcome to the Empirical Cycling Podcast. I'm your host, Kolie Moore. Today, we are joined by our Empirical Cycling coach, Rory Porteus. And I want to thank everybody for listening and ask you to please subscribe to the podcast if you are liking it. And if you are new here, especially, and you like what you're hearing. But also, if you're a returning listener, you can always support the podcast by giving us a nice five-star review wherever you listen to podcasts. We've got a lot of those and more would definitely help. So thank you for all of that. It's one click. It's the least you can do, I figure. and also if you want to give us a nice review that would be really great but also more importantly because we are ad-free if you'd like to donate to the show and support us through that because we're ad-free content you can always visit empiricalcycling.com slash donate and if you would like to hire us for coaching or consultation please shoot me an email at empiricalcycling at gmail.com it's currently February and especially if you're in the northern hemisphere I know we mostly have a lot of American listeners. It's a really good time to start thinking about planning for the upcoming year. Whatever sport you are doing, or discipline rather, not sport, just discipline and cycling. Please keep it cycling related. And if you would like to ask us questions for future podcasts, please follow me on Instagram at Empirical Cycling. And usually do podcast questions up there. But we're going to skip this week because I know a lot of it's just going to be Mostly asking further questions about what we're doing here. So as you've seen in the title, we are talking about practical proxies for stimulus. What on earth does this mean? Rory, before we hit record, you actually gave a pretty good synopsis. So why don't you give us a pretty quick explanation there? Yeah. How do you know if your training's working without looking at heart rate or power data? Okay, great. Very succinct. You said it was a good way to describe it. I'm not going to change what I said. Yes, absolutely. This is one of the things that we do in coaching all the time, where we need to give our clients some kind of way to know, even beyond hitting power targets or getting your heart rate in the right zone or whatever you want to Consider there. How do you know you are getting the right thing out of your workout? How do you know if your VO2max intervals are working? How do you know if your threshold intervals are working? Because if, like, let's say your threshold's gone up and you do your 2x20 and you come home and you're like, you know what? I don't really feel like I worked that hard today. You know, if you, I mean, sometimes that's good, but a lot of the times you're looking to build your fitness, then you want to think, How am I going to know while I'm writing that I'm actually improving the thing that I want to improve? So that's what we're going to talk about today. But we have to do a little bit of a preamble because there's a lot of ways to misinterpret what we're going to talk about today. And so I want to head off all of that stuff before we dig into it because of the potential for misuse. Probably chief potential misuser number one when I learn about a new thing because I want to think, what's the limit of this? Where can we apply it? Where does it break down? And so the biggest thing I want to start with here is that stimulus is not adaptation. Stimulus is turning on the certain things that are going to make us improve at whatever aspect of fitness we would like to improve. So if we would like to improve our VO2 max, what aspects of our interval set can we lean on to think, I'm probably getting a good VO2 max stimulus here. But if you don't recover appropriately from that stimulus, you will not get the subsequent adaptation. Stimulus leads to adaptation. So adaptation always happens with recovery, and that's where you get your supercompensation. Rory, you look like you're bursting with dots. Yeah, so I guess the simplest way to try and explain kind of what we're thinking about here is you can have however you choose to define the highest quality intervals in the world, but if you're not going to eat enough, you're not going to see any sort of adaptation. So this is maybe and you're the one that came up with this idea for a podcast. This is maybe thinking along the lines of how can you partly ensure that you're going to achieve the potential adaptations but also know within the interval and post-session that that went as it should rather than did it just go well? Yeah. And so here's another thing. that I also want to head off is that you cannot use these proxies for stimulus as ways to hack around a workout. Like a quick example is if a proxy is like concentric muscular fatigue, we'll dig into that in a little bit, but let's say that's our proxy. That basically means If you try to push hard on the pedals, it's just not going to happen really. You're aiming to push for like 1,000 watts and you get like 300. There is some concentric contractile fatigue. If you don't eat or sleep for like two days and then you try to do that, you're going to get there real quick. And does that mean that that's a good way to approach these intervals? No, that actually means that your intervals were really bad even though you achieved the proxy that we're talking about. One of the examples I see that comes up a lot whenever people talk about things that come up in this podcast is high-cadence VO2s. So would you say that a good example of what we're trying to get away from here is I did intervals at high-cadence in an attempt to do high-cadence VO2s, therefore I will see adaptation, where in reality that's maybe not what we're expecting. The high-cadence itself is not. the thing on its own that is going to drive that adaptation and make the workout a high-quality one. It's everything else alongside that you have to think of as well. Right, yeah. So the proxy is a physiologic cue that we can tune into that will tell us that we are probably in the right range. And so just because you're doing one thing or another, that seems appropriate at the time does not necessarily mean that you are always going to yada yada down the line. Actually, one of the first things I ever saw in the training media that made me think of something like this was probably in the mid-teens, like 2013 to 2016 or something like that. I think I had seen Joe Friel, maybe it was on Twitter or Facebook or something, having an exchange with somebody. Somebody said, okay, well, I'm in the hospital. I had this bad accident or stuff like that. My heart rate is like 120 BPM. Does that mean I'm getting zone two adaptations? And Joe Frioka responds and goes, no, because your cadence is zero. And so that's actually a really good way to think about how not to use these proxies because if you are going to use something like heart rate in order to... Gauge or Fatigue. And Rory, you know, I talked about this on the Training Zones podcast, and we can do the same thing with heart rate. If you're thinking about heart rate zones, if your heart rate, if you're watching a scary movie and your heart rate gets up to like 150 BPM and your max is like 170, like are you getting threshold adaptations? No, because your muscles aren't going anywhere. But all that adrenaline is flowing. That's true. And stress is happening. But you can also get stress from work or family or relationships. And that does not actually mean that you are going to be getting fitter because you are experiencing the proxy, but you are not experiencing a stimulus. The secret to Teddy Pagatra's success is that he also works a 60-hour work week alongside all his training. Off the bike. Off the bike, really. He's a stressful accountant. It's just all that cortisol running through. Hyper-responding. Moving around rich people's money or whatever accountants do. I have no idea. I'm not rich, so I have no accountant. So, let's see. I guess, is that kind of the end of the list for ways people could potentially misuse this, or am I missing something? I think the small summary to put at the top is just don't rely on everything you say that we say in this podcast being a guide towards magic intervals because those don't exist. True. Although magic does exist because otherwise Penn and Teller would never get fooled, I guess. That's true. So let's start with something easy. Do you want to start with recovery? I don't have recovery on the list. Maybe let's not. Actually... I think you could do a good recovery one. Because here's something that I experience a lot in coaching where my usual cue for a recovery ride is feel better at the end of the ride than at the start. And I've seen people still ride at one watt below... their Coggin Zone 2 range and say, I felt better at the end of this. I did an hour. My Zone 2 starts at 150 watts. I did an hour at 149. And I felt great. Even though they probably should have done that ride at like 80 watts. And that's the abuse of the queue. I think a good proxy for a recovery ride is that you kind of forget that you're doing it like you have to go through the process of getting onto the bike although we should stress that you don't have to do a recovery ride on a bike you can go for a walk but if you're on the bike it's short enough and easy enough that you're kind of just not thinking about what you're doing and if you are thinking about what you're doing it's because In your mind it maybe feels pointless. It's not pointless, it's very important, but it's a ride of sufficiently low intensity that it maybe feels pointless, but it's not. Yeah, in which case a lot of people probably wouldn't want to get on the bike, in which case, like you said, go for a walk. And don't walk like you are trying to casually escape from an animal that you don't want to realize that you're actually running away from it. Like you don't want to walk with any purpose. You want to walk like you are taking your grandmother for a walk. So that is probably a good way to think about a recovery ride. So let's move on to endurance because endurance riding, the stimulus of endurance riding is kind of a strange one because between my coaching experience and what I've seen in the literature, The biggest proxy for endurance adaptations is something that you don't really feel on the bike. Like if you spend, like if you do three hours on the bike and, you know, normally you can, you know, a four or five hour endurance ride feels fine, today you've got three. You do three hours, does that mean that you are not getting an adaptation? Is the purpose of endurance to do more than before? In which case we would all have to get to a hundred hour... weeks on the bike at some point in order to increase the stimulus. I don't think that that's necessarily true. I think for endurance, I personally find that the best proxy is total hours ridden regardless of intensity. So your recovery rides count towards this, your high-intensity rides and races count towards this, group rides count towards this, all intervals count towards this, and even your just regular old endurance rides, or as some folks would call it, zone two. So that all, to me, counts for endurance stimulus. What is it? How about you? I think that's a fair way to put it. I think the question a lot of people would end up having is, as an example, if I was doing extremely hard intervals, such that, let's say someone's doing 30-30s and they're doing for five minutes each time, so a thoroughly miserable workout, If I'm doing that two times a week, how does that count as endurance then? So if you do those rides and they're two hours long each, I would just say you've got four hours of total volume. Because volume is what I see drives endurance adaptations the best. So a lot of my clients who are professionals... The more they ride, the better fatigue resistance they have. And it's kind of a one-to-one correlation. And of course, there's only a certain amount of ride time that you can practically do before you've got to either start cutting intervals or it becomes too much or you can't even eat that much in a week. You hit FoodMax, as you've said. And there's, by the way, a lot more to come on FoodMax. You're going to love it. So yeah, when it comes to... endurance. Yeah, total volume, regardless of intensity, seems to be a good way to think about it. And I would even go so far as to say that somebody's total moderate intensity activity, like if you walk your dog or something at something that's not grandma pace, I would go so far as to say that that probably has a somewhat positive impact on your aerobic fitness based on a lot of reports from A lot of my friends who do a bunch of cross-training in addition to their cycling, like they'll do a lot of hiking or they'll do a bunch of swimming or whatever else, running, that all seems to have an effect. I wouldn't count it one-to-one. It would be like, Rory, this is probably not something you're too familiar with because this is strength training, which we can, we'll talk about your experience of strength training in a little bit. He's giggling right now. We'll do a case study on me at some point. We will do a case study. But if I would count other sports, like maybe except for like running or cross-country skiing or something like that, I would count other modalities of moderate exercise as like a half of a set. So in strength training, something like a bench press typically counts as like a half set towards your triceps because the triceps have a lot to do in a lockout of a bench press. And so if you are looking at your total tricep volume in relation to something like hypertrophy, if you only consider the things that you do directly on your triceps, like skull crushers or like pull-downs or something like that, that kind of stuff does not fit tricep hypertrophy as good as counting like bench press sets as like a half set towards your triceps. And so that's how I would Consider cross-training in terms of all this. But none of this is to say that there's a real practical way on the bike to know that you are getting this stimulus other than to know that you are on the bike. And to me at least, that's more than sufficient. I think one thing that has come up a lot in the past couple of years is the notion of zone 2 training, which I know we've discussed as a phrase we hate. and the worst examples of people trying to do this are the ones that are just doing endurance riding be it at the correct intensity or slightly too hard whatever it ends up being often especially if someone's already fairly well trained you see them asking questions about why they haven't gotten fitter and it could be in many cases that their absolute volume has gone up but the lack of intensity has resulted in and the needle not moving sufficiently for them to have felt it was a worthwhile thing to have done. And so looking at whole volume rather than endurance riding specifically, I think is another good way of trying to encourage people to think about everything they're doing on the bike leading towards like that ultimate goal of adaptation towards like literal endurance but also things like fatigue resistance. And if someone was just limiting it to the time that they were doing Zone 2, whereas they could be doing a 20-hour week, maybe they're doing like 17 hours of Zone 2 total of that, but they'll adapt a lot more than the person who's just doing 17 hours of Zone 2. It's everything else on top of that, which is why we think of training plans as being like, you have to look at it holistically, you've got to look at the entire... The 10,000 foot view, you gotta see the forest, not the trees, you gotta take the big picture, yeah. Yeah. So, it's actually interesting that you mention that, because I think a lot of people consider, based on what I've heard put out there, it's that you can ruin a quote-unquote zone 2 ride by riding too hard, it like spoils the... What's it called? The metabolic milieu? I think that's the only French word I know. Is that French? Anyway. I know that the US is bad right now, but I'm confident that your high school French taught you more than milieu. Well, that's great, because I only took high school Spanish. I have four years of Spanish. I can order a meal, and I think that's probably about it. Which means I know zero French. Dos, gracias. So, yeah, I think if you consider that a Zone 2 ride would be spoiled by intervals, including what's supposed to be like 30 minutes afterwards to get back into the right quote-unquote zone, by the way, direct measurements, if you're thinking about that, of epinephrine and... and fat oxidation and all that other stuff, the metabolic milieu in the blood, all that stuff actually resets really quickly, like within a couple minutes. So I wouldn't be too worried about that per se if that's the way that you want to interpret it. But according to everything I've ever researched, and I've been doing this now for over 10 years, not actually the reality of the situation. What you are burning metabolically does not have anything to do with the adaptation that you get. It's the total volume because the proxies, like we've discussed many times on the podcast, are actually more like AMPK activation and sirtuin activation and the presence of calcium elevated for durations. That's the kind of stuff that we're looking for. I think Wattstock 40 was probably the one where we went really deep into kind of why what substrate you are oxidizing does not lead to endurance adaptation. Okay, threshold adaptations. Let's discuss threshold because, you know, in terms of, think about subsequent adaptations, you know, endurance through threshold, so all the way up to like FTP and even beyond, to me, counts as, It's sort of like a sliding scale. It's kind of a continuum of part motor unit recruitment and part metabolic load on the muscles that are going to be reflected in things like sirtuin activation and APK activation and MAPK activation, all that kind of good stuff. That all is a continuum. And so, to me, a good way to consider threshold work is to consider it as, as Andy Coggan always likes to say, it's, it's, and Tim Cusick, it's muscular endurance. It's probably a great way to think about it because a lot of times, especially once you're well-trained, doing threshold, for instance, is not going to raise your threshold or your V2MX or anything like that, but it can and will give you really good Muscular Endurance. And so in order to be assured that you are getting a good stimulus for a threshold, my usual suggestion is to get to about the place of total interval duration where you start to feel like your legs are getting very tired. At the limit. Yeah, they're at the limit. You're getting probably the burning sensation in your muscles, the active ones. For a lot of people, that's the quads. For some people, glutes are included in that too. and you have to really focus to maintain your threshold and that is usually a sign of many things and one of them is increasing motor gain or recruitment and so that all says to me you are probably getting a good threshold stimulus is getting to that point of muscular fatigue but like we said before if you For instance, do a bunch of really intense sprints. Let's say you race a criterium, and then afterwards, you're riding home, and you're like, I'm going to do some threshold efforts. I bet you are probably not going to get very many high-quality threshold intervals unless you're super, super, super well-trained. In which case, that is a way that you would not want to hack around this proxy for adaptation. So I'd agree with a lot of what you said there. I think that I don't, so unlike Kolie, I don't have the ability to recall exactly what episode of a podcast I said it on, but at some point I came up with the notion of a concentration gradient. That being, whenever you're doing these sorts of muscular endurance type efforts, one of the things that changes as you go from like a Tempo, Sweet Spot, up to FTP, is how hard you really have to think about what you're doing, or I guess, to put it another way, how, how, I've completely backed on a word. I think what you're getting at is probably what I would say that this mostly reflects is the, a lot of it's probably going to be motor unit recruitment. is the higher neural drive that you need to recruit larger motor units, but also you're going to be getting warmer. You're going to be making a lot more heat, and that actually will increase the amount of internal load that your brain is seeing and integrating into your total RPE. I would also suggest that if you are going faster for a while, that may also be like an external cue of like, okay, I'm going really fast. I'm probably going pretty hard right now. Your heart rate's going to be elevated. Your breathing's going to be elevated. Like all that kind of stuff, you know, and with increasing exercise intensity, you get increasing epinephrine release and you get increasing blah, blah, blah. So between all of that, that's where your brain starts to go, all right, this is definitely getting harder. I mean, it's that, the weird Borg scale of like, What is it? 6 to 20 or something like that? Yeah. Whatever happened to 1 to 10? There is... Oh, my brain just wants this word. It's so entertaining to me to watch this. Essentially, there's a lot of different things that change as you go from tempo up through FTP. One of them we can also talk about is breathing. It's still like you can almost... Nose Breathe, if you're doing tempo, I find. Sweet Spot, it's, the breathing's picked up, but it's definitely not something you're even thinking about. Threshold, you're maybe aware of it, but it's not ragged, and that end point that we're talking about for these sort of intervals is where all the different things that you watch for in terms of RPE targets for the intensity, that's when they start to fall off a cliff, and it's not because you're suddenly starting to do it wrong, it's because you've started to reach the limits of what you're capable of. Your breathing starts to go ragged. And I tend to find it's very sudden. It's just, you know, one minute you're fine, the next minute I start to like begin to fall apart. When your breathing goes ragged like that, yeah, a lot of the time, that's actually another cue that you can use to triangulate on your threshold is that if your breathing goes ragged, and especially if you get that RPE decoupling, usually that means you are actually over threshold and have been for a couple minutes. That's another thing that you can think about is for threshold, in order to know that you're even in the right range, your muscles have to be hurting, but your breathing should be labored, but fine, like not ragged, not gasping. And oftentimes... For threshold work, right when you get off the couch, a lot of the time, you don't even need to find any of these things in order to get a good stimulus. If you're in the first couple weeks of training, if you've just been noodling and you haven't done any efforts yet, it's most likely that if you do a 2x20 at tempo, you're going to get some adaptation, even if it doesn't feel hard and you're not hitting any of these proxies. But as you get better and better trained, you are going to have to get closer to these because at some point, like we said about folks just doing quote-unquote zone two riding, you can do that for a while. And some people can get pretty fit on that kind of stuff, but they're in a very small minority is what I find. Most people actually have to do some proper hard work in order to see some improvements. And so, yeah, so like between muscular fatigue and breathing, being labored but fine, that's probably where you can pick up that you are doing threshold work properly. And this is actually one of the things that I see, especially in very well-trained people, like Conti riders, World Tour riders, ultra-endurance athletes especially. I know there's a whole bunch of you guys and gals and folks in between all listening. For ultra-endurance, Tempo is like race pace. How long can you hold a 12-hour race pace? A fucking long time, right? And so going out and doing tempo intervals can be good to get some pacing in, especially if you're tired and you can't do proper FTP work and you want to do some maintenance. Tempo is great. However, if you are looking to build fitness, this is where I find tempo, according to the Coggin power levels anyway. to you and me is probably like just over LT1, kind of between LT1 and getting to sweet spot. This is where- Gravel ride pace. Yeah, gravel ride pace. So I think that you can't ever really get to true muscular fatigue with tempo. And we've talked about this briefly on the podcast before, I believe, but it kind of bears repeating. And so that's a lot of the time where if you're really looking to build fitness, unless you've got other reasons to be doing tempo, and there are plenty, sure, I would personally want to dig more into like sweet spot threshold type work and especially if you're a time crunch and you're looking for a better endurance stimulus like muscular endurance stimulus going more sweet spot and threshold is probably a good way to go yeah the thing to remember that I've joked before that tempo through to FTP is the same thing but the reason you often don't get tempo Prescribed as part of a workout is ultimately going to be that thing of, yeah, it's the same thing, but you need to do more of it. And there's a food and time requirement that for most people that's not going to end up being suitable. And so you can end up doing an awful lot of work and the payoff at the other end is perhaps not going to come around to, you know, something that would have been less energetically intensive. Yeah. And this actually goes, towards another kind of principle that we've had on the podcast since like the first, I don't know what, 10 episodes or something like that, is that quality threshold work usually means more time and zone, either continuous or total. And there's, you know, if you're looking at which way do I progress, there's really no wrong way to do it as long as it kind of feels right and you're seeing some progression, you know, like let's say we start ridiculous, we'll do 60 by one minute at threshold. and eventually you'll do 30x2 and then you'll do 20x3 and then you will eventually get to 1x60. Yeah, you are increasing your continuous time and zone and anybody who's ever tried to do something silly like that and there's a couple of us out there, you know that the first workout, 60x1 minute, is like it's tedious but it's doable. But doing 60x60 minutes like straight, that is something that needs to be built up to. So... Yeah, I remember this was like a year or two ago. I had an athlete who had done an FTP test after we thought their FTP went up and we wanted to check it and you told me give them four to six by ten minutes at FTP and see how it goes. And the shock was that they managed to do all six and a seventh. because that's how good they felt on that day and that's less representative of where their TTE was at because when we actually went and tested their TTE it was not 70 minutes long you'll be shocked to hear but the nature of how that workout was structured whilst it told us where their FTP probably was the structure of it did not represent in itself an optimal way for them to have trained FTP, I guess I would describe, because they could have done less total work if they removed some of the rest periods, much in the same way the person doing 61-minute efforts could probably have done a 2x20 and gotten about the same stimulus. Probably. Although equating stimuli or equating stimulus between 60x1 minute and 2x20, honestly, I think it's a fool's errand. and I spent very little to no time considering stuff like that because I used to a lot and I got nowhere and we'll talk about not always reliable proxies and we'll talk about some ways that you would potentially be able to measure that because that is, I mean, that's one of them, just time and zone is occasionally not a great proxy. So we got breathing. muscular fatigue, and time and zone. Concentration gradient. Concentration gradient, as in, are you having to concentrate harder? Yep. Not something that is in chemistry, as that makes me think of always. All right, VO2 max. Here's a fun one, because I'm on record many times as having said that your breathing is a good proxy for VO2 max stimulus. So breathing hard itself is, while you are doing the appropriate intervals, a good proxy for stimulus, breathing hard itself is not the stimulus. It is far from the stimulus. If you just sit there and take a bunch of deep breaths, you are not necessarily going to be getting a good VO2 max stimulus. If you start sucking on supplemental oxygen. You are not getting a good VO2 max stimulus. If you just raise your heart rate and you start hyperventilating and sucking on supplemental oxygen without doing any, if your cadence is zero, as Joe Fro would say, you are not getting a good stimulus. And this is, I think, one of the things that may trip people up when they quote this proxy to others, because it always should come with the asterisk that this is not related to the actual stimulus. The actual stimulus we're looking for is cardiac function. We're looking to increase heart stroke volume because that is one of the biggest limiters of VO2 max, as we've discussed in the podcast many times. So that is probably the biggest thing that I wanted to clear up because I think if you are going to quote, you've got to be breathing hard to somebody else as a proxy for a VO2 max stimulus. If somebody's aware that breathing hard is not the stimulus they're looking for, then they're going to go, that's bullshit. Often when you introduce a new athlete to doing VL2s, breathing hard is one of the first things you tell them, but we're not telling them that because that's the goal of the workout. We're telling them that because If they get to a state where they start breathing hard, they're more likely to be doing the right thing to get the actual adaptations that we're looking for. It's like the ticket in the door. It's not the show you've gone to see. Yeah. And I'll give you another way that Via2Max does not necessarily work is like if you do a really hard, long sprint. like 20, 30 seconds or something like that. I remember the hardest, I can remember it to this day, like it gave me low-level trauma. The hardest I've ever breathed after a sprint was the best 20-second sprint I've ever done. I did 1,550 watts for 20 seconds. After starting around 2,100, I just kept on the gas. After I was done with that sprint, my vision was gray. I was about to vomit, and I was also about to soil my bib shorts. And I was sitting there on the side of the road dry heaving and breathing through my eyeballs. That was not a VO2 max stimulus. Like, I think if I were off the couch, sure, getting your heart rate up like that, yeah, okay, fine. But that is, it ticks all the boxes, but I'm not doing an interval. that's like two to six minutes long or even eight or sometimes even longer. So if you are doing VO2max intervals like you were doing like a five-minute full gas effort and you are breathing and your heart rate is high, okay, now we're getting somewhere. Like if you've got the proper intervals in your legs that you are performing, now you are very likely to be getting a good stimulus. But that proxy itself, is somewhat unrelated to the stimulus. So heart rate is also sort of a way to approximate this stimulus. And I say sort of because of a couple things. Usually one of the things that we see while people are doing VO2max intervals or even just Getting Back Into Shape. Some of the highest heart rates you ever see for an entire year, like let's say somebody's season goes like October to October. October is when somebody takes a break and the next October, you know, late September or something like that, they take a couple weeks off the bike and they start training again, then you get to a round of testing. Usually for that calendar year, that's when we're going to see the PR heart rates for the year. Because in January, You've been somewhat well-trained. But after detraining, your heart rate is going to be very, very, very high. And the drop of max heart rate during training is actually pretty normal. It doesn't drop a ton, but it will drop some. So heart rate is sort of a good way to look at this. But I think especially if you are doing the high cadence variety of VO2 max efforts, it's actually pretty typical. That the heart rate that you see, the max heart rate, is going to be lower than you're used to even for like a full power, full gas, five minute effort. Like five minutes at like 80 RPM, your heart rate is likely going to be higher than five minutes at 110 RPM. And we've discussed this on the podcast before, but the reason for this is you get a lot of muscle pump. With the more rapid contractions, you get a lot more blood flowing back to the heart. And so you can actually... B, at the same VO2 max with a lower heart rate by returning more blood to your heart. And that is kind of the fundamental reason that VO2 max heart rate, in my experience, is typically, while you're doing high cadence severance, lower than it would be otherwise. So like if somebody's max heart rate might be 185 to 187, Sometimes they may not even hit 180 doing VO2 max efforts or like 182 or something like that. And they'll go, my heart rate didn't get up that high. And it's like, were you breathing really hard? Were you pushing as hard as you can? Was that all you had? Yes. Check mark. Great. Green check. Please move on. We probably got a good stimulus here. doesn't really think about this mechanism here, is that when you consider heart rate as a proxy for VO2, if you just think about that alone and you consider that stroke volume is always going to be linearly increasing with heart rate, then when you get to, or rather, if you are not getting to your max heart rate that you've seen, That would imply by that philosophy that you are not actually hitting VO2 max, you are actually sub max. But that is actually not what I've really seen in the literature. So I don't necessarily think that that's really always applicable. And even sub max, like if you're just riding endurance pace or threshold, if you raise the cadence, this is most people's experience with increasing cadence. It'll raise your heart rate rather than lower it. And that's why at VO2max, it's counterintuitive that it would actually drop. But you are most likely hitting your highest heart stroke volumes at that point. And so please go listen to VO2max series in order to get many, many more nerdy details on that. Do you have anything to add on VO2max proxies aside from my monologue? I'd probably reiterate there's a reason that we don't necessarily give out 30-30s versus like steady state intervals I was thinking about that but I was gonna just skip them but yeah go ahead dig in and those are maximal intensity workout they will absolutely get your heart rate up they will almost certainly make you faster in certain specific ways but it's not necessarily going to be something that comes about as a result of Direct VO2 Max Improvement. Similarly, it's entirely possible to do the steady state VO2 Max workouts and have wattage improvements that do not result from VO2 Max improvements. So there's a lot of ways to skin the cat and it's not always going to end up with the right cat, I guess. Sorry to all the vegetarians and vegans out there. and to my two cats that are wandering around behind me. Also, yes, to Peanut and Miso. Speaking of seeing improvements without seeing VO2 max improvements, there was actually a paper recently published that we're probably not going to do a whole episode on, but it was looking at low-cadence, high-intensity interval training in a group of young women. I think they were like age 17 to 20 or something like that. The figures in that paper was, in my opinion, not that well reported, but they charted VO2 max improvements versus ramp test power improvements, like W max improvements. And the R squared for that relationship was only 0.3. And so that was, I think it was, are you looking at the paper right now? Uh, yes. So go down to the, there's a chart of like five graphs all together, and I think it's the bottom center or something like that. And they don't report the R squared. But basically, the interpretation is that the about 30%, only 30% of the variance in the REM test improvements can be explained by the improvement in VO2 max. There was a very wide range of improvements in VO2 max. And so to me, I don't think the authors mentioned this, but to me that says that a lot of the improvements in the intervals is actually due to either anaerobic capacity or neural drive or both. And this is something that we've actually seen in the literature a lot where, for instance, if somebody adds strength training to a training plan without VO2 max improving, you can see an improvement in RAM test power. and in time trial performance without any improvement in VO2max. There was a paper by Adami that we looked at a long time ago, probably, I think that was right at the start of the VO2max series, actually, where somebody's anaerobic capacity, between anaerobic capacity and the ramp rate and their critical power, you can actually calculate and predict what somebody's... RAM test max value would be. And so this is actually a proxy that we can talk about not always working that well, is using power as a proxy for your subsequent adaptation, which is maybe a little beyond what our scope is here, but maybe we can touch on it in a minute. All right, so speaking of anaerobic capacity, Let's talk about stimulus for anaerobic capacity. Speaking of 30-30s. It sucks. It sucks. If it feels like it sucks, then you're probably doing it right. Probably not. No, I'd say, yeah, you're doing it right. So the way that I usually tell people that you're in the right range for anaerobic capacity is that you feel like you are getting to concentric contraction failure. This is where we talked about earlier. If you are trying to sit there and you're trying to push 1,000 watts and you're getting 300, but your RPE is 10, there you go. You are probably getting an aerobic capacity stimulus. And this is one of the things that 30-30s are great at. And I tell people, full gas, seated. And if you're a really good sprinter like me, you could probably take a minute rest in between or maybe even 90 seconds to do a full set. But at some point... You are, yeah, it just sucks. So like, here's a... Nine minutes. Nine minutes. That's cruel. I mean, to do like five 30-second efforts for somebody, if I were going to go out and do that right now, as poorly as I am right now, I would have to take... I thought you meant nine 30-second efforts. I was like, that's dope. I mean, maybe over two sets. That's what I would get. I would do five in the first one, and then I would do four in the second one, and I would try to do the fifth, and then I think I would probably lie on the side of the road instead. So, a lot of the time, I see people actually afraid of this workout. And I think that their fears are well-founded and reasonable. And you've got to be a psycho sprinter, like somebody like me, in order to really enjoy the hell out of these things. And I do. So, when I do these... Here's how the power usually goes. For somebody who's scared, we'll actually see increasing power across the set. And I usually tell people, if you feel like you can barely push the pedals by the end of the last 30-second effort, it's likely that you're in the right range. But I tell people to start hard. Everyone should be full gas. So my 30-second efforts for all seated typically look something like this. First 30 seconds is about 1,000 watts. second 30 seconds is like maybe 7, 800. The third 30 seconds is like 5 to 600. And then the fourth and the fifth are going to be somewhere between 4 and 500 maybe. And by the last 10 seconds of that last 30 second effort, I'm probably pushing anywhere from like 200 to 250 watts. And just miserable and gasping. That is, to me, the good proxy for anaerobic capacity. And you can get here doing like a one-minute hill climb, just smash it, and by the end, your legs are kind of achy and not feeling like they can push hard. You're probably also getting into the right range. And even in like a five-minute effort, and this is where we get crossover. So if you do a five-minute full gas hill rep, you can have a good VO2 max stimulus by breathing hard and having a higher heart rate and all the other good stuff. But if your muscles are giving out at the end too, you can also be getting a good anaerobic capacity stimulus. And a workout like that, you've got to make sure it's going to serve the purposes that you have at the time and that you can account for the muscular fatigue because there's a lot of muscular fatigue with something like that. But it's a pretty good... crossover stimulus. And I have definitely given these efforts to people. I think people think I'm kind of anti this kind of VO2 max effort, but I'm definitely not. I do give them to people all the time, but they have to serve our purposes. Yeah. To give some numbers from a non-track sprinter, I looked up someone who did these a week ago, and he goes from 630 to... For the 30-second averages? Yeah, so... 6.30, 5.76, 5.67, 5.61, and then the last one is 5.52. That's pretty good repeatability. Yeah, that was his first set of them. Yeah, I assume it falls off. What's the last 30 seconds of the last set? Like 400, 450? His second set's actually stronger than that one. I'm guessing there's some gear finding there. 5-4-4 for the very last one. That's really steady. That's not typical. Yeah. He's strong. All right. Well, very good then. Well done to the athlete who's listening and did these on the 25th of January. Yeah. And, you know, as somebody gets better and better trained, that is more kind of what we would hope to see, especially so these repeatability of those efforts is improving. But yeah, I mean, really, there's no other way to do it other than getting to that muscular fatigue. However, another way to hack this wrong would be to get there tired because a lot of high-power efforts require you to have full commitment, full watch. You've got to be fresh. You've got to be ready to go because, you know, like we've kind of joked about before, if you start to do one of these efforts, and you can't even push hard to start with and you're like, oh, muscular fatigue, there it is, stimulus achieved. That's not the way that this is actually done and if you get there by like not eating enough on a ride, like if you do these at the end of a ride to work on some fatigue resistance or something like that and you can't really do them to a high quality, you can't really push hard, they're probably not giving you what you want. Yeah, I don't know about you but I find that there's a and good muscular endurance, yeah. Yeah. And also people who are, like really anaerobically capable of. They're the people I'm more likely to give it twice, Kolie's flexing. Because those are the people that, you know, if they're good anaerobically, it's because they adapt well to this sort of thing. So you can probably rely on their ability to do them a little more often, provided they get everything right in between. Because it's still an awful lot of work. It's still an awful lot to recover from. Well, and especially if you're not doing much else. Yeah, you can do these twice a week. But if you've got competing goals, like you're also trying to improve or maintain muscular endurance, if that doesn't sit well with you without some training, then you've got a reason to only do this once a week. It's not like you've got to do a block of these and maximize it. I don't think I've ever given somebody a block of just anaerobic work. It's all going to have some kind of aerobic component. to it and definitely accounting for the fatigue. I usually, if I'm trying to get someone ready, usually crit racers, I'll usually start with a block that's all anaerobic and then merge into a bit of both as we get closer to the races just so that you can try and maximize how fresh someone feels for those specific workouts where you want the adaptation and then once you've gotten them over the first. Shock to the system that they are. You can maybe give them a bit more alongside that as a way of helping fine-tune everything. That's not a bad idea. I would totally give somebody like a week, like to count a week as a block, like maybe two workouts like that or something like that. Yeah. Okay. Anyway, next proxy is sprinting. Now sprinting. is a curious one because the, especially depending on the kind of sprinting that you're doing, there can be some, it can look not great while you're doing these efforts, but actually be really, really good for you. So depending on what you need to work on with your sprint, I mean, just getting on the bike and sprinting is This is going to sound really dumb. Getting on the bike and just sprinting at your hardest is one of the best stimulus that you can have for sprinting. It's specific. It's maximal. I mean, it's called neuromuscular power for a reason. There's a skill component to it. Practicing that skill matters. And until you get into the weeds of sprint performance, max is max. And that, I hate to say it, is one of the best ways to consider Sprint Proxies. And I mentioned this on the podcast before, but watts, big watts is probably a good indicator that you are fresh enough to actually be doing the workout. Because I think I've mentioned this podcast before, like I said, when I used to go out and do a lot of sprinting, I do much less now, but... If I'm going to do a sprint workout, and I head out and I'll do like one or two seated sprints to start with, and if my seated sprints aren't like at least like 1600 watts, like peak, I'm like, yeah, I'm not feeling great today. I'll probably just go home. I'll just not do this. If anyone feels small like I do, then just remember those are relative values. These are very relative values. My 84 kilo frame with 25 inch quads. So your personal numbers may be higher or smaller. So if you're used to seeing like 800 watts for a seated sprint or 900 or you do a couple standing sprints and you're used to seeing like 11, 1200, 1300, and suddenly it's like 10% down. Like you're used to seeing 1300 and suddenly you're like, oh man, I can only crack 1150 today. That may be an indicator that it's time to go home. Maybe try another one if it doesn't improve immediately. Yeah, you're probably not fresh enough. But other than just smashing the pedals, there's not a lot of good proxies during a sprint workout other than feeling like you can actually smash the pedals. It's pretty cut and dry caveman, which is maybe one of the reasons I like it. As a disclaimer there, obviously, I'm going to guess most people that listen to this are in the Northern Hemisphere, and if you're in the Southern Hemisphere right now enjoying summer, then I hate you. If you're doing these sorts of seated sprints on the turbo, I would only compare backwards to similar seated sprints you've done while fresh on the turbo. because the mechanics of how a turbo works and flywheel speeds and your ability to exceed the resistance that the turbo can offer is going to distort what actual watts you're capable of doing. So don't be disheartened if you see that your seated sprint power is 200 watts less. It might just be that you're doing it on the turbo and that's where that's caused. Yeah. And then if we, of course, look at our power... Power Force Velocity Curve. As you go outside of your normal cadence range for peak power, your peak power is going to drop. Does that mean that that's less of a stimulus for you? I would say depending on what you need to work on, it may be or it may not be. So if you race on the track, and I get this question a lot from folks who race on the track, how should I modify my training to... to be specific for the track. And I usually tell them, do seated, high-cadence sprints. And it's not going to be your best power, but relative to other sprints like that, you want to see that power improving. And it's pretty simple. You've got to make the conditions similar, especially because, like we said, the skill component is here. You've got to compare like for like. It's like you cannot Necessarily compare like a high bar back squat to what you can leg press because those are different skills and if you do nothing but squat for a while then you get on the leg press you are probably going to see rapid leg press improvements but if you're doing both at the same time You know, you're probably not going to see anything like that. Then if you leg press for a while, you don't squat, you go back to the squat, you're like, man, I can't really squat that much at all. Then you improve the skill. And the same thing happens with like seated max sprints, sprinting on the turbo, sprinting uphill, sprinting downhill, sprinting on flat ground, like sprinting at high speed, sprinting at low speed. These are all things that can add context to the watts that you are making. And for some people can be pretty consistent and some other folks, not so much. I'm a not-so-much folks, and I actually, when I'm doing sprint training, I need to actually be highly specific to those conditions, otherwise my training isn't really that good for the events that I'm doing. So that's maybe a question I was thinking about asking when you started this and you said a good sign that sprinting is working is that you're doing good sprints. Department of Redundancy department. So I guess... To broaden the question on the sprint side out, you're obviously more of an expert on sprinting than I am, but there's a lot of different types of sprint workout in a way that there's maybe not so much for other intensities. So things like tractor pulls, things like standing starts, you know, the different ways in which you can train sprinting, how would you go about identifying like the... Common signs that the workout is going well. And don't just say sprint numbers good. I guess I can't say anything that can I. Actually, this is where people who are really dedicated to sprinting are... probably doing some strength training as well. And anybody who's done a decent amount of strength training will know what the mind-muscle connection is. And I'm a huge proponent of this kind of thing. Where feeling the muscle appropriately and feeling like you can really push it, like I started bench pressing recently. And I think today, for the first time, I actually felt like I could actually push with my pecs, like feeling how to actually use them in the bench press. Because otherwise, I think it was all triceps or something like that. and that's what you're looking for in a good sprint is you feel like you can really hit the pedals like you if you've ever like done a high cadence sprint you'll know what I mean when I say that if you are not that comfortable at high cadence sprints you haven't practiced it enough it feels like the pedals just getting away from you like you're trying to push and the pedals like running away faster than you can actually grab it to push on it And that's the kind of thing where after a while, if you're going, okay, man, I can really feel like I can smash these pedals, I really got this. That kind of mind-muscle connection, I think, is probably a good way to tell that you are getting somewhere. So essentially, being able to feel out the maximal component of that type of effort. Yeah, it's almost like when it's really starting to click. It feels, it not only feels natural, but also feels like time slows down. Even if you're at like 150 to 200 RPM on the track, it feels like you can anticipate that muscular contraction and you can really nail it and you can really just push, push, push. It's magical when it happens and it fucking sucks when you're like kind of on the beginning curve of that. It really does. So yeah, sprinting is fun. and it's both like caveman-like and potentially very nuanced, kind of like anything. You can break it down to a lot of components but at the end of the day you just got to get out and do the work. You managed to answer that question without just saying watts. Yay! Also watts. Alright, now I want to, we should talk about a little bit in the gym because in the gym we're looking at Two things, strength and hypertrophy. So a good way to think about strength in the gym, and we're going to have to, like we just said, the mind-muscle connection thing and the skill component especially. Kyle and I did an episode on the podcast a couple months ago about the implications of, I think it was called the training implications of strength as a skill or something like that. And it was, the gist of it was that if you Kind of like I just said, if you don't squat for a while, you get back into the gym, you're like, man, my squat sucks. I was squatting two plates. I was squatting like, you know, I was squatting 100 kilos and now I can only squat 60. I mean, it's likely that you haven't lost much proper strength, but the skill component of that movement has gone away. And so that's the kind of thing that we're going to have to not really consider too much here. We're going to have to think about beyond the skill component of these things. Although, we can't not, which is the dumb part of why all of this. So, with strength, the good proxy is feeling like you're near maximal motor unit recruitment for fairly low reps. Like, one to five range is typical for, like, strength. And, of course, you can do, like, sets of eight, sets of ten. There is definitely a continuum here. But for true max strength, usually you're looking at sets of 1 to 5. And feeling like you are doing that with an 8 to maybe even a 7, maybe even a 6. We'll call it a 7 to a 9, maybe even a 10 out of 10 RPE. Although I would never suggest a cyclist actually maxes out a lift. That's where you can... basically be assured that you are getting a good stimulus. And in the gym, actually the outcomes are so kind of cut and dry, like did I lift more than last time or was it the same and did it feel easier or harder? And those are all the same components that we can think about in training, right? It's like if you go out and you do 2x20 at threshold and last week it felt easier and this week it feels harder, but oh, I forgot my afternoon snack before my ride. Okay, no wonder it felt harder. Okay, no problem. Still got a little time in zone. RPE was a little high. Moving on. Like, you did it. And in strength, it's like, just seeing the numbers, kind of like in sprinting, just seeing the numbers move up over time. I mean, we're talking like weeks to months. That's a good way to know that your strength stimulus is even working. You're getting the adaptation. But just being able to complete a couple heavy lifts. is really the biggest sign that you are getting a strength stimulus or it's the easy way to consider it anyway. Would you say that it's perhaps much the same as like a threshold workout in the sense of you have a goal for the intensity and total time and if you can successfully manage the number of reps that you were aiming for the given RPE that you were targeting. And it's coming out to the right RPE much in the same way like you fail at threshold of that final five minutes. You're failing, or hopefully not failing, failing on your final couple of lifts. That's where it really starts to bite. Is that kind of where you're getting at? Yes, except I think in strength. You don't ever really want to, unless you are like a power lifter or something like that, you don't ever really want to feel that close to failure. You can actually get a good strength stimulus without feeling like you're really having to grind out that last lift where you get to like a zero RIR. Like that was all I got in me. If I did another lift right now, I would fail it. No questions asked. Like, I don't think you actually necessarily need to do that. But, you know, over the... Over the longer time, of course, even if you're looking at higher rep ranges like, you know, the typical hypertrophy range everybody talks about, 5 to 30 reps. Of course, it can go beyond that, but you've got to make sure you're getting to muscular failure. That's the hypertrophy hack, or the proxy, rather. But there is some strength stimulus to that. I mean, there can't not be if you're lifting more weight over time. But, you know, even with all this crossover, typically, separating strength and hypertrophy from each other a little bit and occasionally think about some crossover range like 5-15-ish reps or even 5-10, that's probably a better way to consider it. Did I actually answer your question? I don't know if I did. What was my question? Basically likening the same sort of signs of Have I come into this sufficiently fresh that I can accomplish the goal that I wanted to achieve? Yeah. And then be able to translate that to the improvement next time. Basically, you know, the sort of compounding improvement of each set. Yeah, I would actually say because of the neural component of strength and hypertrophy, like all lifting basically, because, you know, you really only get to the same type of muscular demands in sprinting on the bike. If you're in the gym, you're getting, and you're doing like a set of like, like a heavier set of three, let's say, like a 7 out of 10 RPE. Because of the neural components, some days you may actually feel like you've gotten other reps, some days you may not, but over time, you should see improvements, like over like weeks to months. And because over a short amount of time, like today in my workout, I did basically the same thing as I did last time, except I think I got another rep here and there. and I know that also I'm like four weeks into a diet right now and I'm not going to be feeling amazing in the gym and so that's pretty normal and so I know over the next couple weeks I should see my performance improve but it's going to be slow because my recovery is slightly impaired and that's fine but over the very very long course of time that's where you kind of see that you are getting these stimulus and that's the same thing where like when you're sprinting You know, some days I'll hit 1800, some days I'll hit 1900, like right now, these are like my numbers. Some days I'll hit 1700, and I'll like occasionally I'll crack 2000. Does that mean that it's like bad if I don't hit the big numbers? Not necessarily for the frequency that I'm training with. So it's, so yeah, like I said, the neural component here. has a very large influence. And so just because it's not going to be your absolute best ever PR doesn't mean it's not worth doing. I think one thing you touch on there is the context-dependent nature of a lot of the things that we've talked about today. And your example there of trying to lift heavy whilst also trying to lose weight at the same time changes the expectations you should have around some of the markers that we're talking about. So like the aggressive example we talked about earlier is if you didn't eat properly for two days and then tried to do a threshold workout, you might not make it anywhere near your intended TTE. But if you were perhaps trying to carefully nudge threshold whilst on a diet, you could get close to TTE, maybe you get past it. How that's going to feel in the aftermath as well is going to be very different because of the limitations that you're putting yourself under which we should always remind people make sure you're feeling your rides before and after and during like that's irrespective of what you're trying to achieve with diet but the way something like a diet can affect everything else the same way that coming back from injury or illness is going to affect an awful lot of what we've talked about today. That can change the sort of RPE of the expected RPE. And it doesn't mean that, it doesn't mean your work's going badly. It means that something's just a bit different and you should always account for that in whatever it is you're doing. And I would even say that acute fatigue can have an influence here too. Because this is typical in season for folks. Get somebody to touch on some muscular endurance, like a little bit of threshold or sweet spot stimulus kind of between races. Like let's say somebody races Sunday and they're racing the next weekend. That Wednesday or Thursday, if it's been a little bit since they've done a little bit of muscular endurance work, I want them to do a little bit maybe midweek. And so like Wednesday, if I give them sweet spot, and previously they did like maybe 90 minutes or two hours of sweet spot total at their best during a build, they're not going to hit that because of the fatigue that they're experiencing, and they need some time to recover. And so having like a suboptimal, or if you were building would be suboptimal, like if you did a 2x20 sweet spot where previously you did like 90 minutes, you're like, okay, it's about half the time I did before. It felt pretty hard, but it was a good touch-up on the stimulus, and I'm going to race better again this coming weekend because of it. Great. That's awesome. So the context there matters. And so if you are considering like a build phase and you are not seeing pretty consistent improvement day-to-day, and you're going to have one or two here and there that are off, okay, sure, no problem. But over the long term, you should be seeing those improvements, whether they're happening rapidly or a little more slowly, especially if you're like stressed at work or you are not eating enough or something like that, like I am right now. That's all to be expected. I've got a good example that just arrived in my inbox, which means the person that did this ride will know exactly who they are. They've been doing some threshold workouts, did 5x10 midweek, and then today we're told 3x5 for 12 minutes, basically trying to experiment with higher watts that he's doing. and the interesting note that he's picked up in the start of his comment is that he found it easier to push through and take some more pain in the afternoon on a weekend than it is in the evening on a weekday. At the end of the third interval I felt about the same as I did on Tuesday. I thought for sure I was about done but it kind of plateaued there and never got harder after that in the last two intervals so I was able to get all five done. And that's a good example of how the context of a lot of this changes maybe what you should expect, how a workout should feel. And I think people who are forced to do things early morning are probably one of the ones that are most affected by this because you have to deal with the fact that you've just woken up and you're a bit groggy, you're probably quite dehydrated, you haven't eaten for hopefully at least eight hours. All these things are going to change how a workout can feel. and you've got to either acknowledge that in terms of what it is you end up experiencing in the workout or find ways to mitigate the bad or promote the good. So for example, for someone doing things very early in the morning, how do you manage your warm-up to make sure that you're actually trying to go once it's time to start doing the intervals? How do you make sure you time your food in such a way that you feel like it's going to benefit you for the workout but it's not going to leave you flat because you did it too early? All of these sort of different things outside of the context of the workout itself are going to impact what the workout actually is. And that's all important information to take on board again when we're talking about the sort of things that we've talked about today. Yeah, so I think expecting some variance in that on your day-to-day is definitely expected. I think actually it's more... Noticeable with Strength and Hypertrophy and Sprinting than it is with pretty much anything else. Because you can have a pretty bad day and still get a pretty good amount of threshold work done. On your absolute best day ever, you may be able to get in an extra 20-minute interval. So let's say somebody's doing 3x20 and they do it, and on their best day ever, they might be able to do 4. But on their most mediocre day ever during a build, You do 3x20 and it felt pretty hard, but you could do it? Great. That's that kind of variance that we would probably see in the middle of a training block. And sometimes you can really test your limits and really dig deep and get in one of those big performances. Like, all right, I did 4x20 today. Man, I smashed it. That was great. There's a cost to that. There's always a cost. And so whether you actually dig that deep or not, probably something that I would say maybe should only happen occasionally because especially if you're really well trained, you can really properly dig yourself into a big hole by giving yourself one of those big days. Anyway, we are way off topic, aren't we? As is our way. But I think that actually I did want to touch on all that kind of stuff because the context and the kind of day-to-day variation of all this stuff. matters a lot. And so before we actually dig into our less reliable proxies, I wanted to talk a little bit more about hypertrophy stimuli. So if you are trying to maintain muscle mass during a diet like I am right now, or you are trying to grow some muscle in order to improve potential strength and anaerobic capacity and things like that, I'd say the most reliable proxy for hypertrophy, like I said before, is probably getting close to failure. within the context, like you can actually take this very similar to, like you said, like a threshold workout. So if you're always adding a couple reps, like maybe a rep or two or three per workout, even like per set. So let's say this week I do 8-8-8 on my squats. Next week I do 9-8-8. Great, I got progress. Maybe the next week I have a really good day and I go 10-10-10. And when I hit 10s, I'll increase the weight and I'll go back to maybe 8s. Great. progress. But I think other ways to consider hypertrophy, like we kind of touched on this in the advanced strength training episode, other proxies are soreness, localized fatigue, and muscle pump. Now, mechanistically, all of these are actually very dicey as to whether they have an actual effect on muscle hypertrophy. I would say probably muscle pump and soreness have maybe like a 10% chance of being mechanistically related to muscle growth in the long term. And localized fatigue is usually just the best way to know that you're actually hitting the right muscle because a lot of the time people can miss it. Like if you're doing squats and your low back is great, but your low back is tired and your quads are like, yeah, I'm okay. That's probably not the right way to... Maybe you need to change your squat technique or move to a different machine or something like that. But with trying to hack these things, like trying to get around them to big brain these stimuli, you can also be really, really sore and tired from doing a very, very long endurance ride. And is that going to create hypertrophy? Well, if it did, I think Tati Picaccio would be a very yoked man indeed. But he is not. And if he wants to get big, he's got to touch weights. The pump, or not the pump, the soreness and the fatigue are not always great indicators. So if you're doing it and you're seeing progress in the gym and you are maybe seeing the scale Go up a little bit over time, or you're maintaining muscle mass or something like that. That's how you kind of know that you're in the right range for hypertrophy. So let's talk about not reliable proxies. Feeling tired. Feeling tired. Tired in RPE. I'd say actually RPE alone, just on its own, is probably a terrible proxy for a stimulus. Because like we said before, if you just do things that would make you more tired when you do your workout, your workout's not going to be of high quality. So like the high quality workout is a prerequisite for all of these proxies to actually make sense. What else we got? Power. Power's not a great proxy for a stimulus. Because otherwise... We gave the example of power going up from VO2s, but not necessarily indicating VO2 improvement. Exactly, right. If your ATP went up, that's probably a good sign. Probably a good sign, yeah, definitely. But if using your five-minute power as a proxy for adaptation for VO2 Max is not great, because you could do a bunch of anaerobic capacity work and get a lot more power improvements than if you did like... some proper VO2max training, most likely. So making sure that you can separate those variables in your post-hoc analysis is where I would go with that. But also, power may not be the great indicator as a proxy because, let's say you're doing VO2max efforts. Now, this is where VO2max and sprinting have some crossover. So if you are doing high-cadence VO2s, your power is going to be low, but the stimulus can indeed still be very, very high. If you, like, let's say you do 350 watts, and you can do that as like a 5x5 for VO2s, right? And if you are doing this as a high-canes variety, you might only do 310 watts. So if you start at 350, you're just going to like die after a minute if you only think about power as your proxy for stimulus. And so that's where these other proxies come in really handy. But over time... If we just compare like for like, high cadence VO2s to high cadence VO2s, your power, if you're recovering from your efforts, your power should be going up as a really good indicator. Yeah, that is one of the things that maybe doesn't get said enough is an awful lot of the things that we're looking at to see if someone's improving or things that we're looking at on a several weeks scale and not necessarily workout to workout or within a workout. There's a lot of things that we could look at from workout to workout. If you're doing the anaerobic capacity sort of stuff and you're seeing power go up each time, then that's probably a pretty good sign. Likewise, if you did a sprint one day and you get 50 watts the next time, probably a good sign. As long as it's a consistent improvement, it's not a fluke. But an awful lot of the metrics that we're considering are not things that we're looking at for a workout in isolation. And I think that an awful lot of people look at things as, oh, intervals said this for this workout, is that good? And it's like, well, what's the wider context? Like, think about, you know, what's that technique compared to everything else you've done in the past? I'm trying to be as vague as possible about things I'm not allowed to talk about that Kolie knows real well. An awful lot of people see these metrics and they understand that these are things that can help them understand how they're getting faster or could get faster, but they are perhaps looking at them in far too narrow a view like they've got blinders on like a horse. They're only seeing the thing in front of them and they're not appreciating the sort of wider scale of everything you've done in like... the past 90 days. There's a reason WKO defaults to 90 days for when you look back at data is because that's a great little window for you to see what have you done for the past quarter of a year. So I would encourage people if you are trying to look at all these metrics to try and understand what is going on. One, make sure you understand what the metrics are actually telling you. Two, almost never look at it workout by workout basis, like look at everything. Yeah, and when we do see solid improvement workout to workout, I mean that's really convenient and I'm happy about it. but that's it's not always the case like we said before like you can definitely have some kind of variance in your performance as long as it's within a certain window I don't think we've ever really talked about it but there is certainly a certain window where like all of us coaches and even people who've been self-coaching for a while you'll kind of understand okay this is probably a pretty good pretty good performance I don't feel great but like this is still a quality workout and you'll definitely know when it does not fall in that window I think we all kind of instinctually understand this and I would actually say heart rate is probably not a great stimulus for adaptation. Sorry, proxy for stimulus. And I think this because, kind of like what we alluded to earlier of the various contexts of heart rate. So you can be doing a threshold workout. I'm like an 85 to 90 RPM kind of person at threshold. and that's just my kind of happy space and if I'm going faster, my cadence is actually going to be higher. I'll be like, if I'm going downhill, I'll be like 90, 95 and that's great. Slow for me. Yeah. But if I bump it up to like 110, 120 RPM, my heart rate's going to go up. Does that mean that now if my heart rate goes into like my VO2 zone, quote unquote, does that mean I'm now getting a VO2 max stimulus or even if we consider it? heart rate to be a proxy for VO2 or even VO2 itself because my oxygen uptake will increase with higher cadence. Does that mean that if I start to tip into the 90% VO2 max range that I'm actually now getting a good VO2 max stimulus? And I would say no. I mean, because we could say that VO2 is also not a great proxy for stimulus in that same way, but most people don't have access easy to measure their oxygen uptake. you know it's kind of off the table we can use heart rate as a proxy for that but even in its own context heart rate may not always be a great proxy because it can even be up and down a lot day to day if your heart rate decouples over a long ride it could be it could be because you are getting into bigger motor units because you are dehydrating uh and it could be because of any number of things a dog's chasing you um in the south I don't know why people don't Leaster Dogs. Well, I guess if you live in the middle of nowhere, there's not a lot of cars. I get it. I had to deal with that this year as well. In fact, today, I had a dog chase me in the absolute middle of nowhere twice because I took a wrong turn and had to come back up the path. And there the dog was and he ran alongside me for 10 minutes again. Were you trying to steal that charmer sheep or something, Rory? You got to stop doing that. I was trying to ignore the dog as much as I could. It was terrifying. Okay, yeah. So any thoughts on heart rate as a proxy? I mean, everyone knows that heart rate is too dependent on a lot of different factors. The thing I think heart rate is quite useful for in a way that you've probably found this as a coach, you can apply this to a lot of different athletes, is you begin to understand the general pattern that certain sort of efforts should show. And so you can more or less predict if someone didn't have power data, for example, you would be able to identify, oh, this person's doing sweet spot, oh, this person's doing threshold, this person's doing FTP, this person's just sprinted up a hill for 30 seconds. That's the sort of thing that heart rate's useful for is it allows... you to see this is what a person was trying to do in that moment in time, but the absolute values, even for a single person, can change by 5, 10 BPM, depending on context, in such a way that it's maybe not useful in isolation, but you can certainly cross-compare back to your own data. So quite a good way of identifying whether someone's ill or recovering from illness is that their heart rate could be massively elevated for an equivalent effort. And that's where heart rate's useful. But it's not useful in the sense that, oh, I was five beats under my maximum heart rate after doing these efforts. And it's like, well done. But it doesn't really tell you what the efforts was. in terms of effectiveness. Yeah, it's like, oh, I didn't see my max heart rate for the year when I was doing my VO2 max intervals, so therefore it wasn't a good stimulus. Like, yeah, it doesn't really work like that. But I had another thought and it left my head. So I guess we're moving on. So a couple other things that we've kind of touched on that are not great proxies for stimulus are fatigue and soreness. Because I find that If somebody's, for instance, not eating enough after their workout, like you've got a delayed feeding, like you finish a workout, but then you've got to go right to a long meeting or something like that, or you've got to go right to something else, and you don't get a chance to sit down and just have a giant meal and be happy about it, a lot of the time that can actually increase soreness and fatigue and delay recovery, and that's purely anecdotal, by the way. But let's use it as an example. That does not necessarily mean that you know you smash yourself extra hard and you're really getting really fit a lot of the time that can just it's like heart rate it has a lot of contextual factors that need to be considered in order to really use this as a proxy for whether we got a good stimulus because if I go out and do a bunch of sprints I'm probably gonna be pretty tired I'm gonna be brain tired. I'm going to have brain fog after that because of the neural drive requirements for smashing that hard for that long. Does that mean I had a good workout? Not necessarily. My workout might have been completely mid and I'm just as tired as I would have been if I had a great workout. In fact, if I had a great workout, I'd say there's even a 25% chance that I have no brain fog after that, which is unusual after a sprint workout for me. could totally be a thing. And it's happened where I'm like super awake and engaged and I can focus and that's awesome. And so that's that kind of post-workout analysis. Even though I said that after, you know, using that for hypertrophy is like those can be okay proxies, assuming you're giving yourself the right stimulus. For a lot of contexts, it's not. And that's why... things like fatigue and soreness, RPE alone, all of these things are contextual and they require a lot of context in order to be properly used and interpreted as a good proxy. And actually, now I remember what I was going to say was between power, heart rate, and RPE, speaking of context, between those three, We have a pretty good way to triangulate on how somebody's feeling, somebody's level of fitness, whether somebody's getting good adaptation on subsequent workouts and yada yada. So yeah, those, and I even wrote an article on that. I published peer-reviewed journal article on kind of how if you've got those three things, you can pretty assuredly be able to get a good gauge on how somebody's feeling and how somebody's progressing. 

Two left. TSS. It's just... I think a lot of my misgivings with TSS come from it being termed fitness by a lot of people that didn't want to pay Training Peaks for the terminology. But yeah, that's just... It's like a nice overall view, you know. It's the volume thing that we're talking about at the beginning. It's like, if it's going up, then you're presumably doing more than you did before. And whether that is a good amount more or a bad amount more doesn't really tell you well. Again, look at context. How did you get that TSS? Yeah, and I think this is a trap, and we've definitely covered this in the podcast before, so we won't dwell on it too long, but it's one of those traps where if somebody's time crunched, that if they're trying to increase the stimulus, they'll try to increase the TSS by just kind of riding harder across the board. And that does not, I mean, it can work for a little bit, but it's definitely not a sustainable practice. And that's where you want to try to, you know, think about your stimuli through intervals instead of just TSS. And the last one, let's talk about HRV for a second. Because I think a lot of the time for folks where HRV is intended, and this is actually, I think, One of the things that the endurance training world has friction with, with the regular majority population is that if you're just getting up off the couch and starting to get more fit and your HRV is improving, that's pretty normal. But for people who are already really aerobically fit, your HRV going up and down may not actually be a great... way to gauge whether or not you are getting a good stimulus or not. Because it seems, in my experience, once you are fit, HRV going up and down has a lot more to do with your sleep quality and whether or not you are sick than whether or not you are actually getting more fit. Drunk. Or you could be, what, drunk? Yeah. Yeah, well, so I was thinking of sleep quality being implied. Like, if you're drinking, your sleep quality is probably going to suck and therefore your HRV is going to tank. So that's kind of, that's, but I know you've got a couple of thoughts on HRV, but like, I would actually say that those, for those things, if HRV can show you how to keep quality sleep and get good recovery, even once you are fit, if you use it like that, I think it's a great tool. And some people even like it just to, especially if you kind of get sick a lot, like you got young kids or you're in social situations a lot and you tend to get sick frequently. Having it to be an early warning system for potentially being sick, a lot of cyclists use it like that, and I genuinely think that those are great reasons to use HRV, but I know Rory has some misgivings about some HRV measurements. Mine is simply don't pay companies to read that value when you can get a lot of apps that will basically do it for free. I know that Fabiano uses it with some of his clients. I was trying to find it there, but I can't. It's somewhere in our private channels. But he showed us the HRV trends of someone going through a VO2 max block. doing a bit of recovery and then ending the recovery early and instead switching to endurance and you could see the difference in terms of the trend of HRV from when they were recovering completely and it was like coming sharply back into the alignment that it should be and then when it started to go to endurance and that tapered off completely it didn't go flat it was still coming back up but you could see that the person was not recovering as much as they were previously and so HRV is very useful as a tool. Just don't pay companies whatever stupid amount of money for their bad sensor so that you can look at it on your phone and it can lie to you about how well you slept last night. Yeah, actually, having done some projects that are HRV-related, it is very, very easy to get a bad reading on HRV. Very easy. And so having a high-quality measurement tool is actually really critical to getting good HRV. And so the test-retest of measurement, repeatability, accuracy, and precision is a big factor in that. And frankly, I think we should actually just be able to see the signal itself because it's easy to eyeball when it goes wrong, when you can actually see the underlying data. I remember on a Discord server that we're on, someone was playing around with HRV data and looking at the metrics that, is it DFA Alpha 1? Or DFA Alpha 1? Looking at how that ends up getting calculated and what they found was one of the problems with HRV data is the amount of noise that is produced that then has to be trimmed, essentially, to find the true values. I think that was me, actually. You were talking to the person at the time, but they basically showed a scatterplot of the actual HRV data, and it was just like, you have to trim this down, but how do you do that without distorting it? Because as soon as you start trimming data points out, how do you know where to start and end? And that's maybe some of the uncertainty around HRV that I think were probably That's probably improved in some ways in the two years, three years. One would hope. That was one of the things that was adjacent to our project. The HRV signal, anyway, we are potentially about to get into a very long technical discussion that people don't really want to hear. But yeah, it can be noisy. can be very noisy, especially if you build an algorithm on top of potentially noisy data, it can go very, very, very wrong. And that is one of the things that we saw in our project. And the project's not done, by the way. We're still poking out here and there. So, but yeah, anyway, proxies for stimulus, not adaptation. Any final thoughts before we wrap this up? Because we've really kind of really dug deep on this one. No, but I'd like everyone to know that I don't know how long the podcast has been going on for by the time that you're hearing this, but Kolie told me we might wrap this up in an hour, and we've been recording for, it's just about to hit an hour and 50 minutes. So you'll be able to do the math on how much we had to trim out. We did our ADHD thing that we usually do with each other, and so I just, I honestly hope it... led to some really interesting discussion that's kind of adjacent and derivative from the topics at hand. So yeah, I think if you are looking to get a sense of whether your workouts are giving you a proper stimulus, not to say the adaptation and the recovery and subsequent improvement in performance, but if you are, that's a good way to look at the or those are all good proxies for the stimulus. And even then, if you do none of those and you're just seeing your performance improve, sometimes that's good enough. I mean, not everything has to be fancy and big-brained and check a billion boxes. In fact, in strength training, when you over-cue somebody for a squat, push your knees out, chest up and... Keep your head, don't tilt it that way. If you give people eight things at once, they're not going to think about any of them. And so you don't want to overdo it when you go out and do your workouts. Like, oh, I've got to think about these five things for this threshold workout. Just kind of get a sense and internalize it and make it automatic. Because I think a lot of people who are really experienced at training, whether they've done this consciously or not, those kinds of cues are completely automatic. I don't even need to think about whether I had a good sprint workout or not while I'm doing it. In fact, putting it all down on paper and into words is more difficult than me going out and doing a sprint workout and telling whether it was good or not. Anyway, thank you everybody for listening. We really appreciate having you here. If you'd like to reach out for coaching, shoot me an email at empiricalcycling at gmail.com and we are always taking on clients and we also do consultations. So if you are looking to continue self-coaching or if you are just curious about asking questions about physiology or whatever, hit me up and we can get that all set up. And if you'd really like to work with one of us, feel free to hit us up for that. And if you'd like to donate to the show because we are completely add-free, empiricalcycling.com slash donate. If you'd like to ask Instagram questions for the podcast, follow me at Empirical Cycling. And if you would like to participate in the weekend AMAs, and I've got to go answer a bunch of AMA questions right after this, go follow me over there. And again, five-star rating, really one-click, supports the podcast, helps a lot, I'm told. So thanks, everybody. We will catch you next time.