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Expand your running knowledge, identify running misconceptions and become a faster, healthier, SMARTER runner. Let Brodie Sharpe become your new running guide as he teaches you powerful injury insights from his many years as a physiotherapist while also interviewing the best running gurus in the world. This is ideal for injured runners & runners looking for injury prevention and elevated performance. So, take full advantage by starting at season 1 where Brodie teaches you THE TOP PRINCIPLES TO OVERCOME ANY RUNNING INJURY and let’s begin your run smarter journey.
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On today's episode, increasing and preserving your VO2 max with Dr. Will. Welcome to the only podcast delivering and deciphering the latest running research to help you run smarter. My name is Brody. I'm an online physiotherapist treating runners all over the world, but I'm also an advert runner who just like you have been through vicious injury cycles and when searching for answers, struggled to decipher between common myths and real evidence-based guidance. But this podcast is changing that. So join me as a run smarter scholar and raise your running IQ so we can break through the injury cycles and achieve running feats you never thought possible. Dr. Will O'Connor joins us on the podcast today. He appeared on episode 312 and was, well, the title of that episode was your sub three hour marathon blueprint. He is well versed in how to train for performance and was the first person I thought of when coming up with an episode involving VO2 max. If you enjoy this episode and like what Will has to offer, please go check out his YouTube channel. He is doing amazing things over there, helping you with your training, helping you understand training zones. deep dive into the research and how to get the most out of your performance. Today, we discuss exactly what VO2Max is, what are some reliable ways to measure VO2Max, are the VO2 scores on your devices actually accurate? And then we get into some practical sessions you can do to build upon your VO2Max. Very practical. I learned a ton and I hope you do too. Dr. Will, thank you very much for joining me on the podcast. All right. It's great to be here again. It was... Almost 100 episodes ago that you appeared on the podcast. Uh, and so if people unfamiliar or can't remember, uh, who are you, what do you do? And what was, what's your career academic career been like to date? So I have a PhD in sport and exercise science, which would be more specifically, I guess, around performance, uh, metabolism and physiology. Uh, so the crux of my PhD was around. metabolic flexibility and endurance performance. that is metabolic flexibility is ability to be metabolically flexible, high carb, low carb, no carb, keto. So I put people on low carbohydrate diets for four weeks. This is the main study. I also did some ketogenic studies, ketone supplement studies, but the main one was four weeks low carb, four weeks high carb. And we did like a whole bunch of tests within that. And so my whole theory and rationale was, look, all these studies that have been done on low carb haven't been done exactly right to pull out the best understanding of where low carb is going to perform. They were short adaptation and short uh duration tests. It's not going to work for a 20 minute time trial or 5K run. test or anything like that. So I was like, okay, let's do four weeks and let's do five hours or equivalent, the work equivalent of like 120 K time trial on the bike. And this is going to be perfect. And it, uh, wasn't, guess, well, what I found was metabolic flexibility and trained individuals wins out. the metabolic flexibility component is that you can take carbs away or you can give carbs and the body or the muscle. we use that fuel most effectively. So that was, I guess, the start of my academic career. So through that, I was um really lucky enough to be involved in a very active research uh center. So I met my wife there, studying uh anthracyanins and I guess O2 kinetics and manipulating those and becoming uh a better athlete. Um, so that would be like beetroot juice and pomegranate juice. Um, so yeah, that kind of leads on to a bit of today's topic around, uh, VO two max. So I've done hundreds of VO two max tests. So yeah, around that and myself, I was competing as a triathlete at the time. And then during having to write up my thesis, I, uh, got into ultra running because why not? You know, it seems like an academic thing to do. And, um, Yeah. Taking up uh cycling and swimming, taking up too much time to write a thesis. So I got into running. I got into creating content with one of my uh fellow PhD candidates, Dr. Matt Miller. And yeah, so we created a podcast, performance advantage podcast. From there just started getting approached and by a whole bunch of triathletes, cyclists and runners at the time. And now I just. focus on runners and there was a guess around that was 2018. So it was seven years deep and along that journey of being self experimenting and working with runners and endurance athletes from all around the world, as well as publishing a couple of uh scientific studies as well and doing some lecturing and that's the long and short of it. good, mate. And my idea for this topic came about when talking with clients, injured clients who either return back to running too quickly or they run a bit too fast on their returns. And there's this tension that's mounting when they are injured. And sometimes it is their VO2 max dropping or their data, their devices saying that their VO2 max is dropping and they're worried because they've spent all this time building up their fitness. They're getting, for a race, maybe they're getting strong. And they love it. And then they're injured and then they're terrified of losing all that fitness. And so you're the first person to ask to come on to talk about this topic. So I'm glad that you have, and you're extremely qualified in doing so, but can we set the stage for those who aren't familiar? What are we exactly talking about when we say VO2 max? We're talking about the maximal capacity for an individual to utilize oxygen. So we have. the ability to convert oxygen and carbohydrates or fats into a usable energetic source, adizine triphosphate ATP, which is the energy currency of the cell, so that we can spend that to do anything that the human body does and in our case, run. So the more effectively we can do that, the faster we can run. The higher our VO2 max really creates the So we'll get into relative VO2 max and percentage of VO2 max and running economy. But at the base level, it's just you and I can have a number. Let's just say yours is 100 and mine's 90. And that is just the number that you can, of oxygen you can use either absolute, like in terms of liters per minute or mils per kg per minute. So is it an important number to have? Like is, have we seen in the research that it does correlate with running performance, marathon times, 5k times, that sort of stuff? This is the scientific, it depends. So to a level, right? Like if you take a, you won't find, um, an individual. I'll just give you a, kind of a table of norms, 80, um, mils per kg per minute is like world-class. in terms of a VO2 max. 70 is still, I guess, world class. Like 80 and above is, that's your Christian Blumenfeld. It's probably like bigger individuals typically. And most elite Kenyan runners will be around the 70 to 80 range. Now this is relative mils per kg per minute because they're often around 50 kgs. A triathlete is gonna be larger. They'll have more muscle mass. more muscle mass means more oxygen utilization. So therefore like the overall max goes up. Then you're looking at your recreational competitive athlete would be 60 to 70. And this is where you'll find your elite female athletes as well. And then when we're going, it's your, well, if we take a step down from your top age groupers, know, like still competitive. So we'd probably be looking maybe marathon-wise, maybe a 3.15, kind of three hour plus for the men, maybe three and a half hours for the woman. We're probably looking, no, it'd be faster for the woman. But the 50 to 60s, likely where a lot of your audience base would be sitting like very fit, very active, very capable, but not out there running, easily running sub threes. You know, not doing the... off the couch run for six months and now I've run a sub three. So in terms of does it matter, like those, all those numbers do correlate to performance capacity. Right? So if you come into my lab, I test you and you have a 67 VO2 max. I go, how much training you've been doing? Yeah, I run three times a week. I don't really have any structure or anything. I'm like, cool. This guy can be pretty good. Right? If you come in and you've got a 40, And you go, run five times a week and I cycle for four hours at the weekends. I'm like, okay, you, you're not going to be very good. Um, so, so there's that, but then when we go, all right, you and I both have a 70, that means we will both run the marathon, the five K ed, you know, we're even. No, not, not at all. Um, I could be carrying a lot more body fat than you. could, so functionally I. I'm not as effective. And then it all comes down to economy. So the oxygen cost of running at a given speed. So if we're both running four minute Ks, we've got a 70 VO2 max, then I could be running at 60 mils per kg per minute. And you could be running at 55. Now, I can't really do those percentages off the top of my head, but let's just say that I'm at 85 % and you're at 80%. of a relative intensity, you're just so much more economical than me. You will either be able to run that speed for longer, or you'll have the capacity to go faster. we both have, if we're both going to run a marathon and say 85 % of VO2 max, you're going to be going faster than me. But our VO2 max is the same, but my 85 % is slower than your 85%. Gotcha. You use the term ceiling there. Would that be, uh, A good, I guess, depiction of what this VO2 max is. It's like, it's showing where your potential is and that, that ceiling can, I guess, increase if we train it harder, but at a given snapshot, we're looking at how high that ceiling actually is. then looking at other, your history and your training data and your muscle mass and that sort of stuff, it's sort of working out through training, how close you're training at your ceiling. Is that fair to say? Yeah. So. Yes, so a lot of people can, in your audience or just the general population can increase their selling for sure through just the training that they do and the activities. But for the most part, it's not really going to be the most effective area to target your improvement. As soon as we start running, so. a 3000 meter for competitive runners, that would be around the 10 minute mark, 10, 11 minutes. And that's kind of where you'd reach your maximal oxidative capacity beyond that, the combination of anaerobic for taxo acidity and from the anaerobic component. And this is an area of confusion, which I'll get into as well when we talk about something like high intensity interval training or VO2 max training. Beyond that, there's other limiting factors that then diminish our ability to utilize oxygen within muscle fatigue. But so if we're calling it 10 minutes, everyone's pretty much going for a race longer than 10 minutes. We're going 5K and up. So yes, VO2 max is important, but your fractional utilization, your running economy is going to be the most uh effective means to become a better runner. So the closer you can push up to your ceiling, the better. Rather than trying to lift your ceiling and potentially maintaining your economy at a 5k race pace, then you just have a higher ceiling. And through endurance training, that ceiling would typically raise anyway, so you'd shift a lot. And as you get fitter and fitter, the ceiling kind of pretty much just stays as is and you're just working on, on the fractional utilization, trying to push up as close as you can get to it. Gotcha. And so the, there's more trainability or more ability for you to adapt to become more economical. And so, you know, spend your time in training, working on efficiency. And then I guess as a secondary byproduct, your VO2 might increase. That being probably a little bit, but the real benefits and improvements you're to get in performance is going to come from you improving and becoming more efficient. Yeah. Yeah. Um, for the topic of this discussion, like aerobically efficient, right? Your ability to, um, yeah. Utilize oxygen at a given speed and yeah. How much should we trust or rely on or even use? What our data saying, what our Garmin's are saying in terms of, your VO2 max is this number, or it's dropping down to this number. Are they accurate? Are they useful? uh No. So the way FirstBeat Analytics, which um is the company behind the data that you see. So uh they are owned by Garmin. are outsourced or licensed to and I think it's pretty much only Coros that would be using their own kind of VO2 max calculation. Everyone else is pretty much using a very, this is the same, like literally the same product in the backend. And what they do is they will take a speed heart rate relationship and they will create. So if you will walk through it, we'll go through a run, right? Initially they're going to take that say five minute block of data. So they'll take that five minutes and they'll go, okay, speed was five minutes per K, heart rate was 100. Let's test the accuracy of this data. And if there was a 170 in there or a 30, they're gonna throw that away. And they'll likely throw it away because of how it correlates to the next five minutes. Now you're warmed up, right? So now heart rate's actually reading something that was more. realistic for the output because there's going to be an O2 slow component where the oxygen supply to the muscle takes a while to catch up. So then they'll take that and they'll go, okay, so you're running five minute Ks and it's 130, they'll take another five minute block. And then they have to make sure that there is no anomalies in there. So they're trying to measure for gradient. And so if you're running downhill, you're going to be running faster and heart rate will be lower. So now you've got like what looks like a fitter calculation. So they're trying to figure this all out. And what they do is they'll extrapolate out to either measured or estimated maximal heart rate. if it's, let's see if I could do some of this maths in my head. So if you've got a maximal heart rate of 200 and then you're running at 150, right? That'd be, am I incorrect in thinking that's 75 %? Yeah, so what they're gonna do there is assume that along this speed heart rate relationship, we can make an estimate of what VO2 max is, what the loose oxygen cost of running at this speed is for an individual of your weight. And then we can just keep extrapolating that out. Okay, so if you're running at 130 and you're running six minute Ks, we'll plot that and then we keep plotting it all the way. And then, what they did in the back end was they took, um was it mean percentage difference, absolute mean percentage difference or something. So essentially what they did was they did that, they did their calculation and then they measured a bunch. And so they say they've got 95 % accuracy, which then means they have 5 % inaccuracy. Now the inaccuracy where it comes into your equation, it matters a lot because if you're 5 % inaccurate on your max heart rate, it means that your 200 might be 210 or it might be 190, but you're still going to run 150 and that drastically reduces, you know, it's no longer 75%. And so these percentages really start to blow out in terms of accuracy. so it's, you know, whether it's measured or wrong, maximal heart rate, whether it's an estimated, completely inaccurate one, which often happens for older, well-trained individuals. It would be like, oh, you're 40, let's use 220 minus your age. Now it's 180, but you might have a really large cardiac output, like really large stroke volume. So heart rate is really low and your max heart rate is 167. It's like, you just get all these numbers. for everyone who wants a really high VO2 max, warm up a little bit. Uh, then go run downhill, slightly downhill. So the Garmin doesn't really pick it up at one to 2 % on a cold day. You get a nice fast pace with a nice low heart rate and you'll get a really good VO2 max reading. Good way to cheat the system. I like it. Yeah. Same for performance score. So, you know, after 10 minutes, the Garmin goes, Hey, you're, you're in good shape. It's like, if you live on a hill, you're probably always, and you run downhill to start, you're probably always in good shape. Interesting. Okay. Um, If someone wanted an accurate measure of their VO2 max, what can they do? So they need to go to, uh, like a sports science laboratory and use a metabolic cart that can analyze the oxygen utilized. So you can take a constant of the ambient air. Uh, typically it's like, was it 21 % oxygen in the ambient air? What doesn't really matter, but you measure that, breathe it in and then you breathe out and it might be. whatever the volume or concentration of the oxygen, you've got the volume and the concentration of the oxygen breathed out. So let's say it's 20 % in, 15 % out, you've used 5%, what was the volume? 5 % of the total volume of 100 is five liters, let's say. And so then we can interpret one, is, so we can keep doing that up until you stop exercising. So typically we just do like a consistent increase in. intensity or a block increase. So you do, say, three minute stages where you just start out walking, start and then you go progress to jogging and go faster and faster until you can't exercise anymore. And we typically try and time that around that 10 minute mark of intensive exercise. So you'd probably warm up for, three blocks. So you're kind of six to nine minutes in and then those next six to nine minutes are going to be like the most intensive part. Or you do a ramp test where it just just keeps getting faster and faster on like a linear increase. And once we have that, then we can measure the amount of auction and we go, okay, well, this is how much auction and this is the pace you're running at um and or the power output that you were cycling at and this is your max. And then what we'll do is just have you run at a calculated percentage or we'll just pick some time or like pace or power outputs, right? So you're like, okay, well, If you're on a run, a sub three hour marathon or any kind of marathon, let's call it sub three marathon. So I will, we need to test around that. So let's test at 430, 415, four minutes and 345. And ideally those should all be sub maximal. And then we can kind of, yeah, plot those as a percentage of your VO2 max. Cause we already know your max. And so now we know, okay, when you're running 415s, you're running at this percentage of your VO2 max, because we can measure the actual oxygen it is costing you that sort of correlation to the amount of energy it's costing you relative to what you're maximally able to do. And we can have a much more uh insightful prediction as to say like, you're not going to run a marathon for that. That's well within your capabilities. And then to layer in, can add lactate or um something like that as well. Gotcha. Um, I suppose if they were to give you a VO2 max and then assign kind of like a pace to a percentage of your VO2 max, there's also the variability with factors like hydration status and the weather, humidity, incline, like those sorts of things as well. Yeah. It's not a great means to like, um, was it set percentage intensities or anything, because you're often in a very controlled environment and you take an individualized snapshot on that day. And it's often very short and you will be training for a long distance event. even if we did a four stage submaximal test, so there'll be five minutes, you do 20 minutes, submaximal intensity, and then you do the max test again, like maybe 20 minute total. And then we kind of extrapolate from that. But I have no idea whether that is going to be the same readings 30 minutes from now or one hour from now. And so this is where a prolonged lactate test or maximal lactate steady state test can be a lot more valuable because, or a really prolonged um VO2 test, where you can take the measure of the maximum. But you actually want to, and you can get the um submaximal results. you actually want to run for one hour, you if you're to run a marathon, run for one hour and let's see what the fatigue or like decay is, because you might be running at 80 % and we're like, yeah, that's fine for five minutes. But then after 30 minutes, you're running in the inefficiencies start to creep in. Your lack of overall muscular conditioning or aerobic conditioning starts to decay that. And now after one hour, you're at 90 % of your VO2 max. It might still be some max, but it's, it's trending in the wrong direction. There's a decoupling occurring. Gotcha. If someone was to fixate on their VO two max and want to improve their VO two max, uh, what would be some type of workouts or recommendations to build upon it? Raise your ceiling. Uh, so high intensity interval training is going to be. the most effective. when we say this, and this is something I alluded to earlier, we get some slight confusion around VO2 max and VO2 max training, because if VO2 max is the maximum oxidative capacity, maximum oxygen consumption, why would I be running really hard where I thought running at zone two was my maximum oxygen function? So that is your maximal fat. oxidation state, zone two. So that is where we are negating any investment or component of anaerobic metabolism. So if we just say the top of zone two is where you start to crest into, what would say lactate threshold one, where some component of anaerobic metabolism is incorporated, or at least the first point of significant incorporation of anaerobic metabolism, anaerobic being without oxygen. So we have just below that point, we have the point at which we are burning fat, some carbohydrate, and this is gonna be very dependent on, know, fed or fasted state or dietary carbohydrate intakes. So we've got that. That's great. That's gonna be maximal fat oxidation. So that is where we could maximally use oxygen without anaerobic. If we increase our intensity, absolutely we will increase our anaerobic component, the muscles. are too inefficient and need an energy source so fast that we can't just do aerobic, though it's too slow. It's got to get into the mitochondria and go through the electron transport. It's too slow. So we incorporate anaerobic metabolism, carbohydrates. That's where we get the lactate production, acidity. But along that, we also increase the amount of aerobic component. So we're actually increasing both up until a point. best way to help enhance the aerobic component is over exert ourselves beyond that zone too. And the most effective way to do that is try and use as much muscle mass as possible on a sustainable nature. So if we did like a hundred meter sprint and we were as um effective at engaging our muscles as Usain Bolt or like a one rep max squat, then we're like, we'll just burn out. We can't keep doing that. So we do. high intensity interval training. So we're 30 second to a minute sprints with 30 seconds to a minute recovery. So within this, get a large stimulus dose, but then we still get, because of the recovery, we're getting an enhanced stimulus on the recovery as well, because the recovery is the necessity to utilize oxygen to replenish the ATP pool in the muscle that we've just kind of off. And we have a large anaerobic component, anaerobic component. We essentially have the maximal input of both energetic systems, which puts a large stimulus and stress on the muscle cell, as well as bio mechanically, right? We have to run really fast. But because we get these intermittent recoveries, then we are able to reduce the overall stress. And so if you look on a graph and you say did uh So a very classic one in lot of the studies that it uses eight times 30 seconds on, 30 seconds off. And you do that three or four times and dispersed by around like three or four minutes recovery. So you've got eight times 30 seconds on, 30 seconds off. That's, I'll say eight minutes. If you just removed from the graph, all you looked at was heart rate and lactate. what you would see would be almost an identical trace of if you did three times eight minutes at threshold. So uh for the sake of this conversation, we're gonna say threshold's four minute case. And so you did three times eight minutes at four minute case. We got lactate readings and we looked at heart rate and that's all we looked at. It looks exactly the same as if I did the three times eight times 30 times 30. But what you did was you accumulated, what would that be? Four minutes, three by four, 12 minutes above 5K race pace. And so the lactate load, anaerobic load appears similar, but the way you've you've induced the stimulus and dispersed that load is completely different. And in most cases, a far more effective dose than your traditional three by eight minutes. If you were to, depends what you're building up for, know, cause like, and all of that and specificity in your training, but that, if you're just looking like food like you're doing those two sessions, comparing them with each other behind density, interval training is going to be more effective at increasing backtake threshold aerobic capacity and VO2 max. Gotcha. And so you would recommend that protocol. So you go on and off 30 seconds on. 30 seconds off where that 30 seconds is like all out intensity. then you want to be like, um, not all out. I've had people do that. I was like, so what I say to people when I give them this workout is like, just, it's so hard for me to explain, just go do it and you'll know what. Too hard or too easy experience. Yeah. Yeah. Yeah. Like I aim for like your five K pace. Right. So you just try and aim that. And because of GPS, even like if you're using a stride power meter or anything, it's just. It's such a short window of time. You're like, Oh, that was too fast. That was too easy. And by the time you get through three, I'd say do three, when you're more experienced runner, can do four sets of those. Um, and, uh, do that. yeah, you can, you'll figure out what's, what's, quickly take you about one or two attempts before you like, yeah, I started out way too quick or too conservative or yeah. Yeah. Okay. Got you. And just like, it's. Most people will look at it um after the fact, you know, on Strava or whatever their Garmin, and they'll probably, they might see wildly different speed outputs, but often it's just to like the GPS, it depends on where you are and what recording rate you have. There's no way it's going to be accurately measuring a 30 second start stop, you know? And you want to, and it shouldn't be start stop either. You want to be able to jog, like you shouldn't be forced to walk these intervals. It is. more of like a traditional Fartlek training. This is what Fartlek training is based off before, um, in the old Zodapick knew the science behind what he was doing. would the goal be to during these 30 second efforts, uh, try and keep to this, well, let's say the data we're collecting is extremely accurate. We want to try to be having the same speed or same intensity throughout those 30 seconds. Um, throughout the entire, the 30 seconds on that we're doing should remain consistent in terms of intensity or in terms of speed if we're doing it effectively. Yep. Gotcha. Yeah. Okay. And so if someone's getting to their third round and those 30 seconds on a significantly diminished, their effort might be the same. They might be still putting in like an eight out of 10 effort, but their speed is significant, drastically dropping and means that they've gone out too hard at the start. Yeah. So there's definitely a trained component there as well. ah and that depends on what you're coming from. Like if you've been doing just say aerobic bass training, your anaerobic work capacity will be not great. So as soon as you start to enter into some kind of anaerobic work, your ability to replenish and buffer the acidity and lactate that was produced isn't great. So you'll probably get to the third one, not regardless of how hard you go, but like. you'll probably just be pretty stuffed anyway. And you'll find like after two, three weeks, you'll be, yeah, you'll be able to handle, even if you went out too hard, the decay would just like the drop off would be much lower. But the main goal is to just hit whatever pace output and just try and keep nailing that. And as it gets more intensive and challenging, you still are able to produce the muscular force required. And like motor unit recruitment so that we can get that stimulus. Otherwise you start to enter into that gray zone of like, well, you should have just gone even harder if you're only going to do two sets, you know, and got more out of those. then it does transition to a different style of session. Okay. And then for those 30 second rest periods, we don't want to get to the point where we're sort of maxing out and having to walk and like totally. collapse, want to sort of maintain a slow recovery jog throughout that entire workout. Yeah. So we're trying to, we're doing an active recovery rather than like a passive recovery because the goal is not the pace or power output. You know, like if we were training for a 5k and you're like, I want to break 20 minutes. It's like, well, we need to run under four minutes. So let's figure out a session. Let's say we're doing two hundreds. you want to get faster, so we need to be pushing these close to 330. And I don't really care about your recovery. I care about the work and how fast you can go. The speed is absolute importance here. Whereas we're looking for a physiological stimulus here. within reason, it doesn't really matter if you're doing these uphill, downhill, flat, headwinds. You're running at 80 % of your speed capacity or it's like, we're, trying to elicit the, yeah, the overall muscular stimulus. Gotcha. Uh, what about longer intervals? Does that still have, I know you mentioned if we're to do like a three or four minute, you know, threshold or like faster than threshold to push our VO2 max. Um, or is these interval durations that you just described the best way the most efficient way, given the research is out there to boost your VO2 max. Yeah, you can go shorter. So you can go uh to probably around four minutes. So the Norwegian four by four protocol, is just four minutes on and you can take two to four minutes recovery form four minutes on again. Okay, and you're just trying again, trying to push essentially as hard as you sustainably can for the four. And it's the same component where we're just we're trying to get the maximal aerobic stimulus of the muscle to force the mitochondria to proliferate. So make more of them. we're that's all we're trying to do. We're just trying to get more mitochondria. So that's the powerhouse. That's what's going to use the oxygen and the fat and the carbohydrate to make the ATP. The more of those that we have, the more economical we can be at a given speed, as well as, you know, the higher our... our overall ceiling or even the better our oxygen kinetics can become. that is just, if we had all the same infrastructure and we just got a bit more uh efficient at supplying and grabbing the oxygen from the atmosphere, so breathing it in, transferring it from our lungs into our bloodstream, then from our hemoglobin to our myoglobin, which is within the muscle, could just uh focus on that supply and increasing the rate, know, so like the maximal oh O2 component of it, um can help with those O2 kinetics as well. Okay, so yeah, the four minutes, but you won't really be looking at anything over four minutes. Okay, so we're somewhat... On to off ratio is somewhat one to one. Um, if we're doing like four minutes on, we're sort of doing like a three to four minutes recovery and doing that. I just want to make sure you're fully recovered for the capacity to do the work. Gotcha. Okay. Yeah. And all of these sessions, if I'm calculating them all, they seem to be around about 30 minutes plus or minus a couple of minutes. Yeah, that'd be about, that'd be about right. Like someone. Yeah, with a training load capacity. like, there's actually a really good session that we have that is two minutes at 5k pace, and then you drop down to three minutes at 10k pace. And so traditionally, way this was, so this is one that they compared to, um you know, like a 30 second or a one minute on off and it, has equal, I guess, effectiveness. But what it allows you to do is it has a bit more specificity around racing. So most people really struggle to do four of those, whereas I have a couple of elite guys that are looking to run, you know, 28, 29 minutes for 10K, and they can do five of those. But they are there. It's more so their capacity to recover than it is to do the work. So, um, because when you are, have a greater aerobic base, you have a greater means to recover, which in running itself, like a running race is not really that effective because we don't have intermittent races, trail running for sure. But like, uh, it's not like cycling where there's attacks and surges and climbs and downhills. And so your ability to recover, uh, becomes really important. How about for people who. are injured or are sick or are traveling and can't exercise and they're at fear of losing their fitness. Let's talk about how long it, let's talk about the VO2 max readings that they're getting. ah But also the real fear of losing fitness. Like how long does it take to lose fitness? I know you're going to say it depends, but lay it on me. So, uh, was by the numbers. you'll lose fitness immediately, right? Because the numbers are all measuring training load. The only thing they have, if you stop training, there's nothing to infer a response, like a stimulus and response. So that will begin to, on any device or any training platform, Strava has fitness, fatigue, training peaks, indoor, final set, all of these platforms. use just a well they have an infinite system so you could be as fit as forever but they'll just keep using cumulative and acute load okay you keep piling that on it'll keep saying you've gained this many points this many points this many points you stop adding those they start to decline and it's a rolling average so the further you get into it the further it will decline so um numbers wise has no correlation on actual fitness uh i guess the reported numbers are going to be 3 to 5 % within two weeks of VO2 max. Now measured, that potentially could be true, but it is not a direct reflection in that sense of fitness. It's more a direct reflection of a lack of training. uh So in terms of like, if you haven't run for two weeks and then we test you running, you're just not going to be as effective and efficient. And then you've lost plasma volume because you haven't had the stimulus to maintain a large plasma volume. So some oxidative transport capacity is going to be reduced neurologically. There's all of those things where it's just like, it's going to be just harder. You just haven't done something for a couple of weeks. It's just going to be harder. um But actually, they've found in the research after two weeks or within that kind of second week, lean muscle mass increases. because, typically because of the uh prolonged recovery, like the actual ability to recover, assuming you're fueling correctly. So lean muscle mass increases, which can also decrease relative VO2 maxes, mils per kg per minute, right? So your actual weight will go up, but not necessarily non-functional way, not necessarily body fat. But then after that, it's like, who knows? Have you been running 100K weeks or 20K weeks? Because have you been doing that for five years or one year? Because these will all have massive impacts. typically, like within that first month, you will lose conditioning more than you would lose fitness. Right, if you're building up for a marathon, you've been doing two hour runs, you get injured. You have to have a month off running. Because Brody said, Hey, you can't stop running. Then you can't, you can't, you can, but it's going to be bloody uncomfortable. Go do two hours straight out the gate. There's nothing to do with fitness. Nothing at all. it's, it's depends how you could define fitness, but your VO two max and your aerobic capacity, it's not really going to lactate threshold. Like all these things. oh it's not really gonna have a massive impact. It'll be, I'd say like, again, it really depends on where you are in a buildup and where you've come from to say, like, after a month, you wouldn't really notice after a following month that you'd had a month off. You start to get into the six to eight week period of no running or no activity. And now we're looking at a true decline in the physiological infrastructure that is required. How long does it take to get that back? Again, depends on where you've been on that spectrum. Were you one month out from the marathon and you'd been building all the way up to that point? Well, it would take you a while to get there. But if you're just running and you run five days a week and you have done for years, it's not going to take you long. All that infrastructure is essentially there. It's just not yet activated. You're not trying to build new, uh, enzymes or protein structures. Um, well, mean, you are, but like the capacities, the biochemical pathways are already there to do so. It's more of an activation thing than a, like a rebuild or building. Yeah. Um, I sometimes say to people like fitness, it's hard to gain, but easy to maintain. I don't know if you're in the same train of thought, but like my thinking is if you've built in like years and years of like a base of running, very active, uh once you stop fitness, or let's say you are injured, uh the decline of your fitness can be very, very slow, even if you just put in a minimal amount. And so like we say with someone who is bedridden, like it takes three or four days and they've like lost muscle mass and like all these weird adaptations that happen very, quickly when they're very, very bedridden. Uh, however, just walking around is enough stimulus to preserve muscle mass for a long time. And so if we take that similar train of thought and saying, if you walk, if you power walk, if you do some sort of cardio, if you like, just do a little bit minimal dose, you can be very proactive at preserving a lot of the fitness if you've maintained over the several months or years or the training builds and that sort of stuff. Would you be on the same train of thought of that? Yes. And often you have to have a time off because you overdid something, right? Which means you were in a maladaptation period of your training. So whether that was you from the training itself or just life got too much. It got to the point where you either got really sick or you got injured and you know, for your listeners case. Right. And so you had to stop. It's like, well, you weren't adapting to the training you were doing. So if we have a period of recovery, you'll be able to get healthy again, like both physically and physiologically, hormonal hormonally as well, whatever it was like off. Then if you do induce like a little bit of training, so can't run, but you can jump on an exocycle or you can jump on, you know, Zwift or something. And it's like, you'll never do that at the capacity you were running because you were, say, building up for this big running event and you're just not as motivated to get on the bike or go for a walk or something. You might find that that is actually a more specific and personalized appropriate stimulus to build what you were trying to build before, but you actually were building a house on sand. And it just was. on sinking sand almost. So every run was just sinking into the sand because you had no capacity to recover from it. And then eventually you got injured. Right. So often you would probably find that you feel better after that month or six weeks, which, is the, oh, you'd be able to say, but like the typical timeframe of like, okay, we need to assess whether running is making this worse or better. Let's have four to six weeks off. You'll probably find yourself more concentrated on doing all the right things rather than the big bulk thing that you're like run 60 minutes of running gets me 60 minutes of running fitter kind of thing. only have to look at, um, recent example of Hayden wild who got hit by a truck and then just won a world-class triathlon event. And it's more so that he, I mean, this is a theory, but. that he focused on doing absolutely all everything correct in the smallest possible way, like all the small things he could control outside of like running and swimming and he could get on the bike, but he could still, as you say, maintain his world-class fitness and then ensure that everything else was in line. that when he dove into start the race, like he was as prepared as he could be. Hmm. So what advice do you have for the people that you work with if they are. they get to a scenario where they do get injured and they can't run and they are worried about their fitness or let's say VO2 max. uh What advice do you have for them? Whatever. So, the first advice is always go get professional opinion, whether you like to or not, like straight away, just to see if we're dealing with anything serious. And then rest is always best. But you never lose as much as you think you're going to lose. So then you have to draw a line on what is the short term plan. Because the big mistake, I'm sure you've seen it. I've done it plenty of times, is this 50-50 rest train test cycle that just is nothing. It's getting you more injured or sustaining your injury. It's not getting you fitter. It's not making you mentally healthier. It's just like purgatory. you need to, if you're one week out from your event, know, then it's like, decide if you are actually going to do the event. Don't leave yourself wondering, oh, I'll do this. I'll do this. a time. Like I'm going to do a 30 minute run on Wednesday. If I can't get through that run, I'm not doing the event. We kind of, we try to make as uh concrete a plan as possible. because otherwise you just end up just not recovering because you keep wanting to make sure that you maintain some level of fitness. So in the short term, you're like, well, I'm three months out from my event. Just take a week off. Like go see a professional, jump on the bike. Like how bad is it? What is the injury? As long as we maintain the frequency of our STEM, like, you know, if we've training five days a week, can we get on the bike five days a week? Can we jump in the pool? Can we, you know, after the initial kind of rest period, what can we do to keep fit? uh And then beyond that, you typically know what you're dealing with at that point. And then it's like, okay, also how did we get here? Cause you got- What mistakes were made. Yeah, yeah, yeah. Where did you actually start to feel this pain? Before it became a full on thing. Yeah. It's good advice there. think there's like a motivation tension, pull and push type of thing that goes on with an injured runner where, know, if, if they get severely injured and it's like a six out of 10 intensity and they're struggling to like walk even like, you know, running off the cards and they really prioritize rehab, rehab, rehab, rehab. But if an injury is mild and it's like, it's was. quite intense and then it's like 80 or 90 % better. People prioritize, look, I can handle a one or two out of 10 pain if I can still run. And so they then shift their priorities towards fitness or like building upon regaining their fitness. And that one or two out of 10 pain injury just is something I'm willing to deal with if it means being able to run. But then that means for some cases not fully recovering. And so they just hover. Like you say, we need to make. a decision, we rehabbing or are you racing and what are we committing to? Because that 50 50 in between is not going to get us anywhere. You can't really train at your full potential and you're still going to be injured. so, um, drawing a line in the sand, I think is really helpful for people and, um, committing to one or the other, but I feel like, you know, if there is a race that is one week away, then you can do that. Um, switching to the other. priority and then focusing on rehab after that or deciding when is the best time to rehab eventually needs to be in your future. And so I feel like if some people are in the in between uh self-reflect over the past couple of weeks, couple of months and say, is this really trending in the right direction that I want to, or do I need to make some big decisions in terms of prioritizing things? So I think that's really helpful. Anything to add on that before we get to our sort of final takeaways? That would be, yeah. Decide like, yeah. Are you training or are you rehabbing? Don't half, yes. Don't pretend like you're rehabbing. You must see it all the time. If people are kind of, like, just, just don't like stop pretending like you're kind of doing it and, just focus on your running and come to me when you finally falls apart. Right. Yeah. Um, and yeah, that would be the main one. Also the, what's, um, What are you willing to, yeah, kind of like, what are you willing to endure? What risk are you willing to take on? Because a friend of mine, she's surgeon. She's over from Scotland. she's got a stress fracture at the moment. the physio doctor had said, like, look, you can do this race, but that's probably going to write you off for whatever amount of time. And so her kind of stress reaction turned on to still full blown stress fracture, she took, knew that, you know, she qualified for the half Ironman world champs and was like, that was, I just needed to do this race. That was it. And now I'm like, then she's outright just focusing on, recovering and getting it all sorted. But some people maybe don't understand the real risk of like, what they could be doing if this, you know, if they keep ignoring those, those one or two pains, turn into three or four pains, turn into five or six pains. And then you're like, I've been there and it's like horrible. I don't know if you have where you're like running and you just, every run you're just battling with something. And runners are like, hey, come on. It's why we do it. Like we're out there and we will endure. But when it's just never goes away, it's like probably not the most productive. Yeah. And in terms of like, we're talking about, your running economy will suffer. Yep. Yeah. Your performance. like, I think it's, I think self-reflection is a good takeaway here, because if you look at the last six weeks and say, did it, how has it really gone with this injury? And if I don't change anything really fundamental, what does the next six weeks look like? And if it's going to be the same as the last six weeks, you know, a lot of people would then get on board and saying, okay, maybe something needs to change. Uh, so great. So as we. sum this up. Are there any other, I guess, misconceptions about VO2 max and training or any other key takeaways that we haven't yet talked about that you think will be helpful? Um, the main misconception is that it matters. that, it, that what your watch tells you matters. The only thing that matters is your performance. Like that's, that's at the, if you're doing, if you're training for a marathon and you're wanting to improve, then the improvement is the most important part. The, the not necessarily week on week, but like that month on month where you do your your park run or your 10K tempo and it's all getting faster. It doesn't matter what any single number says. If you're getting faster and say you're running faster pace or higher power at the same heart rate, that's fitness, that's aerobic fitness. It doesn't matter. So what typically happens in my training plans, the way I've developed them, is that as you build through, say that, kind of three weeks out from the race to eight weeks out from the race is a heavy period of like high volume and uh moderate threshold tempo work. What there is not a lot of is VO2 max work, like these high intensity interval training sessions, not a lot of that in there. Every single calculation uses those high intensity efforts to either interpret uh critical power and it puts a higher weighting on or it will utilize some kind of a percentage time above at a certain heart rate or something like that. And so pretty much every single person on my plan will have some kind of calculator telling them that they're getting less fit leading into the race. Just because of the way in which like I design my training plans. So when you're running for a marathon, you're doing say, a half marathon at race pace, right, is one of your sessions, you know, and it's 5K warmup, 5K cold air, 30Ks, it's like, and then during the week you did more of that threshold based thing, you know, you've done like those three by eights or four by eights or two Ks or something like that. There's nothing there for like an algorithm to suggest that your VO2 max is improving. And then it's so hard to say that your aerobic capacity is improving because they're just going to use a percentage of max. So it sounds like, your fitness is declining. Despite the fact that you just ran a half marathon with the lowest heart rate you've ever had in the fastest pace you've ever done in training. It's like, that's, that's what matters. When you go do your five K, you go to the club session, you go do that local loop. My wife is just saying, I need to make my loops longer because I'm, running faster. You know, it's like, that's fitness. That's improvement. Great takeaway. Um, as you'll just Answering that, I forgot that we, didn't necessarily cover or ask how frequently do you suggest people do these hit workouts? Well, it's, yeah, it depends what you're building out for, but you could test the effectiveness, like what it's like for you, um because within and how well you are able to tolerate fast paces. Because, know, like as soon as you start stepping towards 5K intensity, some people just start to fall apart. Just the rate of force production is... tendons, ligament, maybe they can't handle it. um But you'd want to be doing blocks of three to four weeks within a recovery week. then probably for a lot of people, if you just did something as simple as those three or four times those eight times 30, and then the following block, do it as the sustained equivalent. So the eight minutes, or for some people that might be 2K or like a mile and a half or something like that. in terms of repeats, just do that. And you'll a good sense of where you're getting a nice return on investment. Um, but doing more than a couple of times a week would be probably like, it would be pushing it for a lot of people. Gotcha. All right, mate. Um, if people are listening along and they're nodding to everything you're saying, and they're blown away by the amount of expertise that you have, where can they go to learn more about your content? Probably just jump on YouTube. uh That is just at Dr. Will O'Connor on YouTube. I have Instagram on there. Like I will see your messages, but I don't really post. And then just drwilloconnor.com for my website. But yeah, there's a lot of stuff that I talk about here is on my YouTube channel. Excellent, mate. Well, I appreciate you coming on here and dispelling lot of the myths and giving a lot of useful practical information. So thanks for coming on. If you are looking for more resources to run smarter, or you'd like to jump on a free 20 minute injury chat with me, then click on the resources link in the show notes. There you'll find a link to schedule a call plus free resources like my very popular injury prevention five day course. You'll also find Run Smarter book and ways you can access my ever-growing treasure trove of running research papers. Thanks once again for joining me and well done on prioritising your running wisdom.