Energy System Myths w/ Tim Kettenring (SSOF Ep 192)

Tim Kettenring3:15

I don't know man, until they align everything within USA Rugby from the top all the way down through to the bottom, nothing will change here unfortunately. But if they did do that and they really put in place proper structures and pathways, they could grow it.

James de Lacey3:37

It would just be very niche. Like I mean you see, there's professional lacrosse on TV like on ESPN Plus and [expletive] like that, and all these other niche ass sports that seem to, I guess they still have somewhat of a following but they somehow are surviving. Like even, isn't ultimate frisbee, isn't that semi-pro as well?

Tim Kettenring3:59

Yeah, it's wild. I mean, lacrosse is kind of an outlier, I think, because I mean, being such an affluent sport for one thing, but then also the demographic that it attracts. I mean, it's self-sustaining because either families or even the guys that play usually will spend the off season working in finance so that they don't even have to have a job in season. They can just go play pro lacrosse for fun.

James de Lacey4:30

I mean, pro lacrosse, sorry. Yeah, ain't nobody playing pro rugby just for the shits and giggles.

Yeah, but it'll be interesting to go down this conditioning road because we obviously have a lot of conditioning topics on this podcast and it's probably one of the more popular topics we cover conditioning on here. So I think the easiest way to set the scene is just covering this, would be a very general question and you just take it where you want, the general misconceptions around conditioning and energy system development.

So I think the first one would be that the three energy systems are somehow independent and they're like on-off switches. And what I usually try, the analogy that I use is that the traditional or conventional view of energy systems is like three lanes of the highway where all three lanes are going to the same destination. So physiologically, regeneration of ATP, but they never cross over.

They're going at different speeds and they, while they all run concurrently, they don't necessarily interact in any way when in all reality, it's like three lanes converging into one. And they're all always active. They're interdependent, not independent, and with the oxidative pathway providing the most support for the other two pathways in terms of function and recovery.

I think that's probably the first one. The second one is that we need to train the predominant energy pathway of the sport more than, in most cases, the aerobic pathway because that's where the majority of the work is going to be taking place regardless of whether the sport is rugby or MMA or American football. Like the outputs are rarely the rate limiter. It's always going to be what's happening between the outputs, between rounds, between possessions when ball goes out of play, and how quickly athletes can recover during that time and how well we can utilize the recovery time from a physiological standpoint.

Tim Kettenring6:29

And then I honestly I don't know how much we can actually affect things on the output side, especially in sprint-based sports that are more alactic in nature because how are you going to, what are you going to raise the ceiling on your alactic power? No, just [expletive] sprint and you'll probably be okay, right? Versus more glycolytic or lactic where you actually have a chance to increase that capacity.

But then on the aerobic side, you increase aerobic power, you're going to improve repeatability. Increase aerobic capacity, you're going to improve recovery between bouts, between sessions, between seasons, between cycles, etc. So I think that is probably another misconception as well is that the volume of work should probably reflect things in that order where, all right, recovery, regeneration, repeatability, those all need to be priorities from an energy system development standpoint.

So we should primarily develop, especially if your sport has an off season, we should spend a good bit of time developing aerobically. And then once we get into season or as we get closer to a fight, like you talked about being 8 to 12 weeks out from a fight, then all right, now what can we do to raise the ceiling on our outputs now that we have the capacity to recover from those outputs.

And then maybe what does the sport actually provide in terms of raising the ceiling on those outputs? How are practices and training sessions structured? Are they periodized? Is there some sort of loading plan in place versus, a lot of the coaches that I talk to work at the developmental level and there's zero, there's no forethought put into designing practices and seasons and things like that. So it's like, well, how do you account for that from a physiological standpoint?

James de Lacey8:56

So how do you, how does, we'll start with this recovery aspect of the conditioning because I think that's one of the main points you made. I think what might be interesting is for the audience as well is what does training aerobically even mean and maybe some examples around that. And then what are you trying to achieve with that when we're looking at, when we're looking at improving recovery between these efforts?

Tim Kettenring8:56

It is kind of a nebulous concept because there's, now that the tech bros have appropriated all things zone 2, right, it doesn't mean anything anymore. So I don't, that's actually probably whenever we talked the first time, that was a lot of my research and then a lot of my content and education was around, okay, well what happens below 75, 70 to 75% of our max heart rate physiologically? What's going on there? Now it's become so muddled and misunderstood that it's kind of a futile effort to even talk about.

But what I look at training aerobically, if we want to use heart rate or if we want to use lactate or if we want to use another some sort of other physiological marker, it's basically everything under lactate threshold 2, which would be honestly for team sport athletes that might be 90% of max heart rate. Because obviously you talk about raising the ceiling on outputs, they're already so conditioned to high intensity outputs, which are probably more aerobic than we realize.

But their ability to still have aerobic function at really high intensities is probably pretty high, higher than conventionally has been thought of. But from a training perspective, it's like, I really like just training at 100% of maximum aerobic speed for pretty high volumes.

One thing that we did in our off season with our domestic players is we did a lot of 80 to 120% of MAS work, really high volumes.

10, 12, 15k a week on feet. But in our kind of base building, and I think that had a pretty high transfer because once we started getting into more games-based conditioning later in the off-season, guys were really sharp from a technical and tactical standpoint.

We were going, we started off with more large-sided games working to small-sided, and guys were much better from a recovery standpoint. We were, I mean, we were turning around games in a minute, minute and a half for a four to six minute game and having very little drop-off. And then once we got into preseason and in-season, it was clear those guys were head and shoulders above everybody else from a testing standpoint and then also just in terms of being prepared for preseason as well.

So I think that's a good kind of jumping-off point for training aerobically is okay, find your maximum aerobic speed and then train around there, whether it's a little bit below or a little bit above. You're going to get pretty solid aerobic adaptations from that. And then assess, reassess, similarly, whatever your assessment protocol is, will show you obviously whether those adaptations are being elicited or not.

James de Lacey12:18

Obviously talking about MAS there. So I guess for listeners, if we're going to just classify it just to make it easy, that will be high-intensity interval training, long and short, whatever across that kind of spectrum. You obviously mentioned before that a lot of the low-intensity, I guess quote-unquote aerobic work, has kind of been fuddled with all the tech bros and stuff. And you mentioned obviously you use this high-intensity approach, but you didn't mention anything about the low, low end of this kind of zone one, zone two.

So I'm interested to hear your take on, is it useful in those, or what scenarios would it be useful in, or if useful at all? Did you use it during that season at all? But did it come into play within anything, or were you just looking at this as kind of your main conditioning modality?

Tim Kettenring12:18

I think a couple years ago if you would ask me the same question, it's no, we have to have some sort of low-intensity zone two, zone one work all year round. If it's in-season, it's for active recovery and autonomic balance, and if it's off-season, that's going to be our base building. But then it's just not practical. From a physiological standpoint, it's responsible because of the cardiac adaptations, but it's just not a practical intervention.

You're not going to—I mean, so Dan Hows said, has multiple times told me, when he was with Crabert and Sevens, he had guys doing four to six hours of zone two work for four weeks in the early off-season.

And I'm like, Dan, how the [expletive] did you do that? What did you do anything else during the week? And he's like, no, we really didn't. We would do our gym work or whatever two or three days a week. He's like, but when we looked at repeatability after that six-week block of high-volume zone two work, he was like, it was, repeatability was through the roof. He was like, guys would have less than a two and a half percent drop-off in an anaerobic sprint test from rep one to rep seven. And I was like, Jesus, that's insane.

But again, for me, it was never practical. I mean, we had three bikes in the gym and a rower. So it's not like I'm going to tell guys, hey, go out and run for 45 minutes and only breathe through your nose. It's like, "[expletive] you." There's no way we're going to do that.

But when I would have guys one-on-one and they're asking me about what can I do to feel better in-season? Okay, well, go hop on the bike for 30, 35, 40 minutes and go as easy as you can, or go walk your dog, go take your kids to the park. That's your low-intensity work, knowing that it's probably going to be more psychologically beneficial for them than it is going to be physiological.

And that's where kind of the autonomic balance element comes into play is if you can get athletes out of hypersympathetic arousal into, not I mean, no, we're not going to get anywhere close to parasympathetic, but at least if we can swing the pendulum back a little bit towards the parasympathetic side, that's going to have nonlinear, exponential effects on everything physiological too.

James de Lacey17:09

I think with that low-intensity stuff too, once you start team practice and whatnot, or even most combat athletes with their practices, you're covering a [expletive] ton of distance and time of not actually doing anything that intense. If you look at even just normal GPS data, you look at how much time you spend under 4 meters per second, under a true MAS or even just walking, it's the majority of the data there. So it's kind of like you kind of cover a lot of it in there.

But it'd be interesting to go into maybe some of the adaptations from these different, I guess, exercise modalities or intensities that you're kind of looking at. Because you mentioned obviously initially everything kind of comes back to the same place, or the road goes to the same place, it converges together. There would be little nuances here and there.

So we're interested to know, okay, what are the adaptations that you're looking at and chasing, taking for example, say, this MAS approach? Then maybe we can go into other approaches as well, but since we've started that, we might as well just go there. What are you looking at improving within those athletes regarding their physiology?

Tim Kettenring18:13

So the way I always try to frame it is you've got three layers of adaptations. You've got central adaptations, you've got peripheral adaptations in the mitochondria, and you've got peripheral adaptations within the arterio-cardiovascular system. From a cardiac standpoint, you're going to try to improve cardiac output regardless. So stroke volume times heart rate. If you work around that MAS intensity, 100% MAS intensity, you're going to see an improvement in cardiac output, but it's going to be more of a force production improvement where stroke volume is going to go up, but heart rate is also going to go up because you're increasing the concentric hypertrophy of the left ventricle.

Versus at lower intensities where you're still going to improve cardiac output, but it's more from a volume overload rather than pressure. So you're going to eccentrically, or you see eccentric hypertrophy, the left ventricle. So you're going to see a volume overload where supposedly it takes 8 weeks of 8 hours or more working under 70% of your max or under 2 millimoles of lactate per liter of blood to see a 1 millimeter increase in internal diameter of the left ventricle, which obviously super impractical again.

But I think the elasticity component can't be understated because even if you're not changing the internal diameter, you're still improving the elasticity of the myocardium of the left ventricle. So seeing that decrease in heart rate to resting, heart rate of work, concurrently with the increase in stroke volume, I think from a health, the health of the athlete standpoint, is super important. How you go about eliciting that, I mean, it's honestly as simple as some of the things I talked about a minute ago.

But then on the other end, as far as improving kind of that force production component, that's where I think the majority of the time for team sport athletes, for combat athletes, for even individual sport athletes, that's probably where the highest return on investment is going to be. Because there's, moving out to the cellular level, looking at mitochondrial biogenesis, mitochondrial density, mitochondrial volume, aerobic enzymes, improving the speed of the Cori cycle and resynthesis of lactate, that's all also going to be, those are pretty strong adaptations at that intensity as well.

So which again, and even above, obviously those are more thought of like Marty Gibala's work on high-intensity interval training and all the aerobic adaptations primarily being in the mitochondria and in the capillaries. That's where that comes into play. But the same thing happens at lower intensities as well because it's you can't decouple adaptations, right? It's oh, well, if you're working at 70% or lower, there's no mitochondrial involvement. Well, we know that's not true. There's going to be some. We just don't know how much. Or if maybe somebody does. Maybe Dr. San-Millan knows that. I don't.

And then from a capillarization standpoint, increasing volume and density of capillary beds. So more myoglobin into the muscle fibers and increasing hemoglobin mass. All those things are, I would say, if we're just using MAS for our kind of framework from 170% MAS down to 60% MAS, you're going to cover that whole range of adaptations adequately.

Then it's more about, okay, well, what does the sport, where's the highest ROI for that individual sport or that individual athlete, and then spend the majority of the time from a volume standpoint at those intensities.

James de Lacey21:34

You obviously mentioned obviously time is a big issue. So hence, hence the use for more intense training methods. So then obviously you mentioned, I guess, kind of those central and different peripheral adaptations. I'm just trying to see where should we go next? What would be most logical? Maybe we can just go down the adaptation road. Then we can come back to maybe the individual.

You obviously you talked about kind of you get that whole range from central to peripheral with all exercise you do. You may just kind of bias or skew it one way or the other depending on the intensity. Is there, I guess, so with the maybe you go through kind of this MAS cycle, what does it look like after that for you? Are you trying to continue to really push maybe kind of the central oxygen delivery component or you maybe looking at more kind of kind of this muscular component?

Is is one maybe a bigger priority to you depending on maybe the time of season and kind of athlete, that kind of thing, or is kind of you're just trying to cover the entire spectrum most of the time kind of say with an MAS approach?

Tim Kettenring23:38

So I think it's both. If you're not delivering sufficient oxygen it really doesn't matter what's happening on the peripheral end. So that always needs to be a component of training or a priority. Now how, obviously how you implement, how those adaptations are elicited is is obviously is individual, but I feel it always needs to be a priority regardless of where you are in annual plan if you have one.

And then that's where also the more kind of working into those lactic and alactic ranges, if you even want to if you even believe that that's a possibility, that's where how you structure practice and and training sessions within the sport I think are going to be more important. Looking at for rugby, manipulating ball and play time to where that guys are going to work into those lactic ranges and they're going to have a ton of blood lactate and then give them very little recovery and then turn around and do it again. Similar to how a fighter would prepare as well.

But whatever is happening from a physiological standpoint in those scenarios has to be supported by how well and how much oxygen is being delivered to the muscles to begin with.

James de Lacey23:38

What is then, what is, and that's a very general question, what is enough? Because if we say if we take say VO2 max, because it's heavily influenced by kind of central function oxygen delivery, we maybe use VO2 max the capacity marker. Is there a, say we even MAS because since it's a proxy measure anyway, but is there a VO2 max where it's okay this is kind of okay, do we need to continue really trying to hammer, I guess, more of these central adaptations for delivery?

Based on what you see in terms of maybe some of these markers, is there a ceiling or not a ceiling, is there a point where we could say I guess diminishing returns?

Tim Kettenring23:38

No, I think so. That's kind of the the caveat I guess of working in those 100 to maybe 120% of MAS at relatively high volumes is that that's also where, again looking at the research on interference effect, that's where the interference effect is most prominent when it comes to speed and power. When there are high volumes of high aerobic work concurrently with strength and power anything neural as well as hypertrophy, that's where there's going to be a good bit of interference.

So that's kind of, it's also a little bit of a boogeyman though because it's like how many athletes are doing eight hours of work at 100% MAS in a week? Not very many. And are they doing low body strength the power session followed immediately by four by fours on a watt bike at 85% of the max heart rate? Probably not. So some of that's obviously how you restructure the microcycle comes into play there.

But in terms of what's enough I think for male athletes a VO2 of 60 really irrespective of sport. Obviously the higher volume the sport I think the the higher that VO2 needs to be. But there are, we had guys that were pushing 4.3, 4.4, some even close to 4.5 on their MAS. So Broncos sub-4:30 who could then also turn around and have a 1.5 10 meter acceleration time and a 23, 24 inch counter movement jump.

So it's, I don't know. I think once you get past that then you're obviously there's going to be an effect or at least even if it's just from a time perspective, you don't have time to work on other qualities because you're so intent on raising that

aerobic capacity or that aerobic power and VO2

that you spend less time on other qualities. So I think that's probably where the the point of diminishing returns is, is when that time spent developing aerobically takes away from strength, speed, power, neural qualities, etc.

James de Lacey28:37

Got it. You cut out a bit there, but I got the gist of it and we'll have in the back end so that it should come through. But when we're talking, I guess, some of these muscular peripheral adaptations, what are some of your I guess go-to modalities? Obviously, you mentioned obviously MAS is one of them that kind of covers a broad spectrum. Is there anything else that you typically like to employ?

Tim Kettenring28:37

So two things. I really really like sprint interval training on a watt bike or on a Concept 2 bike. So the classic protocol of 6 seconds on, 24 seconds off for 20 reps, 10 minutes, has been shown to both improve alactic power but then also actually improve repeatability on feet, even when you do it on a bike.

And then Derek Hansen's 10 by 10 protocol, which is just 10 reps of 10 meters. And you can play with how quickly you want that turnaround time to be. But what I've done in the past is we'll go 10 reps, 10 meters every 10 seconds. Two and a half, three minutes rest and then repeat it for three to five sets, which is a huge volume of alactic work. But

we've seen really really good effects on on repeatability.

What you call is, but by the time you get to that second third sprint then it's just, it's pretty aerobic.

But that's kind of one of those things where it's like if you want your conditioning to look either like the sport or if you just want to make it look hard, but you and the athletes know that this is exactly what you're accomplishing, that it's not just, it doesn't just look hard, but it's actually got legitimate application and and transfer. That's, I think, a top tier intervention.

But then if you want to make it a little bit less shitty aerobic and you want it to actually be alactic, okay, well, instead of going every 10 seconds, go every 20 seconds or go every 25 seconds. So now you've got a little bit of alactic emphasis, but then you've also got a little bit of a mechanical emphasis as well because it's like accelerating 10 meters may isn't going to take anyone over 2 seconds, but the quality will be very very high is the longer that rest interval is.

James de Lacey30:26

Obviously, when we're talking I guess energy systems, I guess we're typically referring to actual fuel use versus energy systems just because of the intensities you use will dictate kind of that fuel coming through. And people will talk about okay they do a lot of, well I guess we say aerobic quote unquote and that's kind of more on that kind of fat utilization end, then we have more of the high intensities with with carbohydrates. Now I guess the sports we're mainly talking about would I guess be predominantly carbohydrate driven.

I guess the question is for sports that are not like pure endurance sports where you have maybe a lot of lower intensity fat oxidization going on, do we even need to really focus on dialing in this idea of improving fat oxidization or doing a lot of as we talked about a lot of the zone one or two when we could just maybe fuel, eat more carbs and and basically maximize our ability to I guess use those systems well, lactate, all that kind of stuff that's going to happen on competition day I guess. What are your thoughts around that? Hopefully I worded that well.

Tim Kettenring32:52

No, I I definitely I get where you're coming from with that question. And that's also something I've changed my mind on a lot of this stuff significantly in the last four years, the more I've read and then the more I've applied some of the theoretical frameworks. Early on I would have been like, oh well we can, we can improve fat oxidation for team sport athletes and we need to just do XYZ. But it's not, not only is it not practical, but it may not, I don't necessarily know that that's important.

Because it's like how much time are they going to actually spend oxidizing using fat as a fuel source in competition versus versus glycogen and carbohydrate sources. And which is another thing that I've kind of come around on too is that most fitness issues are actually fueling issues predominantly. I don't know that I've ever seen an athlete who's just unfit, whether it and it's usually a day of fueling issue or 72 to 96 hours prior fueling issue whether that's in training or competition.

But that being said, I do think, I think increasing carbohydrate intake in general, just across the board for most athletes is probably a better strategy than trying to spend time at lower intensities that isn't practical. Because I think you're going to see more again higher ROI on glycogen stores and also from a cramping standpoint as well because I think that that's probably an underemphasized component of or mechanism of cramping is that not having sufficient glycogen stores in the muscle.

James de Lacey32:52

What regarding I guess your, if we come back to this idea of kind of central peripheral I guess conditioning adaptations, what are you looking, is there anything that you're looking at doing testing wise that allows you to maybe see where an athlete is limited?

Tim Kettenring35:21

So regardless of the sport or the athlete, I like to do some sort of capacity assessment, whether that's a Bronco or a 2K row or maybe a 3 or 4K bike, either to get an MAS or just to get an idea of what that athlete's capacity looks like. And it's really not even capacity. It's an aerobic power assessment. It's not an aerobic capacity assessment.

And then some sort of repeatability assessment that is relatively, it looks like the sport in some way. Whether that's mimicking work rest intervals or including some sort of change of direction if it's a running based assessment, or even something like a Wingate protocol I think would be a good assessment that would actually give you good data on both capacity and repeatability.

But one thing, and I mentioned this earlier, but an anaerobic sprint test, seven reps of 7 seconds on 23 seconds off, add a change of direction to that and then give, do it in multiple sets. So do one test, seven reps, give incomplete recovery. So let's say just two minutes and then do it again and then get a fatigue index from those two sets or even fatigue index from one and a fatigue index from the second. Compare the two.

Having a repeatability data point and a capacity data point I think gives a broad enough perspective on what the athlete's needs are or deficiencies. But usually, if an athlete has good repeatability, they're going to have good capacity. Even if it's not great, it's still going to be good, which, good is good enough.

And the athlete doesn't have good repeatability but has good capacity, then that's either going to be a neuromuscular issue or it's going to be more of a peripheral issue. But I've never had, excuse me, an athlete with good repeatability but poor capacity. So which kind of goes along with the oxygen delivery over oxygen utilization principle.

So but that's generally how I would assess most athletes. I think the only sport that maybe I wouldn't use a capacity assessment would be, well I take that back too, basketball probably wouldn't use a capacity assessment and volleyball I probably wouldn't use a capacity. I'd probably just go repeatability with both of those.

James de Lacey35:21

Repeatability, why is that?

Tim Kettenring35:21

The sport volumes aren't high enough to support it. And basketball specifically is highly lactic. So when you look at LPS data between like 28 and 40% of their running volume is high intensity actions. So that tells me that repeatability is much more important and that capacity probably isn't going to be a limiting factor for most basketball athletes. And I don't know that I would want to do a running based capacity assessment for athletes that have like biomechanically are not good runners.

James de Lacey35:21

Got it. And I guess if we come back to some of the max aerobic speed stuff as well, obviously outside of MAS, I guess anaerobic speed reserve has become a popular, I guess you could say method that's kind of been tagged on to MAS to try and individualize the intervals more for the athletes. So if you would run through kind of what it is, how you even test it and then what that data actually tells you and let you, I guess how does it influence?

Tim Kettenring35:21

So anaerobic speed reserve, actually Gareth Sandford's research on it is what kind of kickstarted this whole journey for me, just diving into conditioning and how to do it better, probably almost 10 years ago. The concept is is brilliant, right? You get maximum sprint speed, maximum aerobic speed. The space between is anaerobic speed reserve. And in theory, if you improve maximum sprint speed and maximum aerobic speed, you should have both better capacity and better repeatability.

And I think what's happened with that is people have looked at only improving maximal sprint speed and saying, "Oh, well that's, we're improving speed reserve and thus improving conditioning," but that's obviously not how that works. You can raise the ceiling all you want, but if you also don't bring up the floor along with it, then you're not eliciting the physiological adaptations you think you are.

So in that sense, it's a really valuable data point and then just the concept, and if it's applied with the intent that Gareth did the research, the intent that he had when he did his research, I think it can be a really good principle-based intervention. But again, I say it's probably misapplied at least in the United States more than it is applied well.

James de Lacey41:59

So by misapplied you were talking about just raising that ceiling versus kind of the whole thing.

So how should it be applied then?

Tim Kettenring42:08

Well, I think you raise both concurrently, right? You aim to improve maximal sprint speed through both sprint exposures and acceleration exposures, but then you also aim to improve maximum aerobic speed by raising aerobic power through whatever MAS intervention or tempo intervention that you want. But you can do both concurrently and should.

James de Lacey42:19

If I was going to just, just to try and throw a spanner in the works here. If I'm going to raise both concurrently, why do I need to know my anaerobic speed reserve? Because the training is going to be similar, right? Or is it, are you going to be individualizing further based on what you get?

Tim Kettenring42:19

So, I know the way that Gareth does it is he's got endurance profile athletes who have high MAS, low MSS. He's got speed-based athletes who have high MSS and low MAS. And then he's got hybrid athletes which have either, let's just say good MAS and good MSS, and then applies different training interventions to each group.

So if you've got an endurance profile athlete, you want to raise their maximum sprint speed. They're going to be more on the intensive end and on the sprint-based end. If you've got a speed profile athlete, they need obviously more from the endurance, from the aerobic end. And then if you got a hybrid athlete, they probably need equal measure of both.

So that's, I'm trying to think how I, I've only done an ASR profile on a handful of guys when I was with NOLA Gold and almost all of them were hybrids, which makes sense. I mean, they were all backs, all rugby players for more than five years professionally. So it makes sense that they would have good sprint speed, pretty high MAS.

So what was interesting though with those few guys is they benefited more from the sprint exposures than they did from the aerobic exposures, which kind of goes to the previous point. It's like how much, how many, how much aerobic exposure is enough?

And maybe ASR is a good way to figure that out. Once you, if you're a team sport athlete, I don't remember what thresholds Gareth uses for how to profile each specific group, endurance versus speed versus hybrid, but obviously individualize that to the sport, figure out what they are for your sport. And then once you get to a certain point, let's just say four meters per second as your MAS, good enough level, then start focusing more on that intensive end and on the maximum sprint speed and speed end.

James de Lacey42:19

Is there a reason that you used it a little bit but don't use it I guess as extensively? Do you just find that you can do most things without it?

Tim Kettenring45:35

Yeah, I mean I kind of knew what interventions most guys needed and because I was a staff of one. There was only so much I could do in terms of interventions, which I'm sure you understand.

James de Lacey45:49

All too well.

Now this just, it's an interesting topic because it's kind of, it's somewhat popular but also not at the same time and it's really only applicable in kind of, I guess mostly team and running based sports because you need that maximum sprint speed, right?

So you don't see it too much round, you kind of see a little bit of the application here and there but it's interesting to hear kind of how potentially it's used to individualize some athletes because you hear like okay this person needs longer rest time or whatever between his intervals because of this etc.

Did you ever take it that far?

Tim Kettenring46:28

I didn't. No. And I know Martin Buchheit and Paul Larsen have similar protocols that they've also both done research with with Gareth. So it makes sense that they would take some of those conclusions and then put them into some of their interventions and their HIT Science content and in their book as well.

James de Lacey46:55

Yeah. Yeah. It's actually I've had Paul Larsen on the podcast for anyone who's interested. Have to go back a few episodes, but we covered some interval training stuff and whatnot back then. But I think that's everything I had for you.

Tim Kettenring46:55

You end up running home for one question. I feel bad for it.

James de Lacey46:55

No, perfect.

Where can people find and follow you?

Tim Kettenring47:19

Just Instagram now. Tim Kettenring I think is my handle and then my website is maverickhumanperformance.com.

James de Lacey47:29

Perfect. I'll link all those up in the description for any of the listeners. But I appreciate you coming on.

Tim Kettenring47:29

Appreciate you having me.