Learn how and why you should select certain intervals, how to integrate them into your training plan, when to do them, and how to properly execute them.
Video Transcript
Intro 00:16
Welcome to Fast Talk Laboratories, your source for the science of endurance performance.
Introduction on How To Execute Intervals
Trevor Connor 00:27
Hello, and welcome to another workshop. This is our big workshop on intervals and how to better execute intervals. That’s a huge topic, so I’m going to say right now this is an overview, we’re certainly not going to cover every type of interval possible, but we want to give you some of the principles, some of the ideas, show you a little bit about the execution that’s hopefully going to help you to perform your intervals a little better.
General Principles of Intervals
Trevor Connor 00:52
So, let’s start with talking about some general principles about intervals, and right now you are looking at what is called, My Yearly Training Plan, my YTP. So, I get to use this just to explain some of the concepts here that we want to get across before we look at some specific intervals. So, just to give you a context you can see up here, the calendar runs across horizontally, so we’re right now in April, down here, what I’ve done is created rows for each of the different types of energy systems that I want to hit, which corresponds with a particular type of work, it helps me when I’m mapping out my season plan, and when I’m mapping out an athlete’s season plan to figure out where the focus should be. The dark purple is what I’m focusing on, the lighter purple is kind of secondary, I’ll do it if I can. You’ll notice I’m never really at any one point focusing on everything or a ton of things. So, that’s Principle number one, that I am a big believer in intervals, and Ryan, you can tell me how you feel, but when I see people doing interval work, where every single day, they’re doing a different interval workout, sometimes it’s Tabatas, sometimes it’s threshold, sometimes it’s sprints, and they’re doing that all through the winter or through their season, I think you are hurting your training, you’re hitting too many energy systems, it takes time to develop one. We’re going to talk about how long you need to stick at different types of intervals to see the gains, but if Tuesday you’re doing one type, Thursday you’re doing another type, Sunday you’re doing another type, you’re just all over the map, and you’re sort of hitting every energy system, you’re not hitting everyone really well, and you’re just not going to see the gains. So, you saw our example you can see my Winter, I started in December doing five by five-minute intervals, and only just stopped doing them. So, that was 15 weeks of one type of interval. The only change that I added is I was doing them twice a week for most of the winter, as we got into March, I started doing five by five once per week, and doing hill repeats, eight-minute hill repeats, and the same intensity for the other workout. So basically, I was doing the same type of work for 14 weeks. You could look at my season here, now I’m switching to more of a high-intensity interval session, doesn’t take as long to see a gain. But the key point being again, I’m going to have one type of interval that I am focusing on at any given point. Ryan, any thoughts there?
Ryan Kohler 03:26
Yeah, this is where I think we differentiate between training and more recreation or fitness too, you know, if we’re training, we want to have a purpose to what we’re doing, and like you show here, there’s very specific things that you’re addressing. If we go the other side of the coin and start talking about, you know, recreation and general fitness, I think that’s where those rules can be, you know, well, they get tossed out the window, honestly, I guess. So, not all the time, but we see a lot of people doing workouts that are following plans or doing workouts with an app of some sort, and the workouts are all over the place. It’s the complete opposite of what we see here, and for those folks, it’s, it’s going to be an enjoyable thing, you know, training is not always the most enjoyable process because like you said, you’re doing the same type of workouts for what 15 weeks basically, and some people get bored with that but to improve your performance, improve your physiology, focus on specific targets, and see changes in those that’s really what it takes.
Trevor Connor 04:32
That’s the really important point, are you doing this for fitness and fun or are you doing this for performance? And fun should always be part of this, but what is the focus fitness or performance? And if you’re focused on performance, you need to be a little more committed like this, to saying I’m going to focus on one system, really train that and then make my shift. If you just want that fun, let’s get some fitness, that’s what peloton is great for. We’re going to be focusing for the rest of This conversation on how to do intervals when you are really focusing on, I want to maximize my performance. So, we’re going to buy us a little bit away from that, that fitness side.
Trevor Connor 05:10
I think another important principle that goes hand in hand with this, that Ryan and I have talked a lot about is, what’s more important is picking the right type of work, being committed to it, and look, we’re going to show you good execution. But picking the right type of work to see the sort of adaptations you want to see and sticking with it to get those adaptations is the most important thing. Whether or not you’re doing it at 101% of FTP or 98% of FTP, who cares? That’s within the range of day-to-day fluctuation and your FTP, if you went and tested your FTP every day, it’s not going to be the same. One day, it might be 250, another day it might be 260, on a bad day it might be 230. So, trying to say, should I be doing this at 98? or 99%? or 101%? Doesn’t matter. What’s more important is, are you doing threshold work right now? Why are you doing threshold work? Are you sticking with the threshold work long enough to see those gains? That’s the important question.
Trevor Connor 06:14
Last really important principle is how often should you be doing intervals? And there will be exceptions to this, but for the most part, one to two times per week is optimal. If you are doing intervals four or five times a week, you are doing them too much. That’s gonna cook you, you’re not gonna be able to execute them correctly, you’re probably not doing them with enough quality and intensity. Not what you want to do, I rarely ever do more than two interval sessions a week, even when I was racing full-time at the pro level, two interval sessions a week was just fine with me.
Ryan Kohler 06:48
Yeah, I think a difficult piece with that, is many people are working to dial back from that, so it’s a difficult change. So yeah, one to two times a week is pretty typical, but I find working with a lot of athletes, we’re going from like, three or four days, or even sometimes five days if we’re talking indoor cycling seasons, and it’s a challenge. So, you should if you are finding that you’re working on pulling back, you should feel like you’re not doing enough, if you find that then you’re actually moving in the right direction.
Trevor Connor 07:17
The final thing, sorry there was one other principle here that I wanted to touch on, which is you should rarely ever do interval work to failure. It’s a rare day when you should finish intervals and go, “Oh, I have to limp home right now.” I generally want my athlete’s and this is how I approach my intervals to say that was a good hard workout I think I could have done a little bit more. That’s how you want to finish most, that’s enough to get that training adaptation but doesn’t destroy you so much that it’s now going to take you two or three days before you can train again.
Ryan Kohler 07:47
I’m glad you mentioned that because I find myself asking athletes a lot whenever they if finish, say a three by 10 threshold workout, for example, the first question is always, how many more of those could you have done? Or could you have done two more? I’ll throw in some variety of that at them, and yeah, it’s a great way to get insight.
Trevor Connor 08:05
Every once a while, it’s fun to go out and see how much you can do and do that epic interval session and go, “Wow, I barely made it home from this.” Makes you feel good, it’s good for you mentally doesn’t do that much for your training. So, keep that sparing.
Four Elements of Intervals
Trevor Connor 08:19
So, before we go into the specific interval types, another important thing to remember is there’s basically four different elements to intervals. There’s the intensity that you do them at. There are the rest periods in between the intervals, it’s not an interval session unless you have rest periods. There’s the number of repetitions that you do and the number of sets that you do. Finally, the frequency, so we just addressed frequency, and my recommendation is no more than once or twice per week. But looking at those others, the number of repetitions, the rest length, the intensity, and sorry, actually also the length of the intervals themselves. Those are the things that you can modify in order to increase the load, decrease the load, affect the training stress that you’re putting on your body. So, we’ll show you examples but let’s say you’ve been doing intervals for three weeks, let’s say you’ve been doing four by four minutes, and you’re now saying I can get through this too easily, I need to make this a little harder on myself. You can do that by, I’m going to add another interval, you could do that by potentially saying I could take them from four to five minutes. Be careful about that, because if you really change the length, you’re probably hitting a different energy system. You can do that by saying okay, I think I’m stronger I can up my wattage and get to make the intervals a little bit harder.
Ryan Kohler 09:42
I think at some point, you’re going to run into that wall where you’ve achieved a limit on your volume, and then yeah, it’s the decision of well, okay, can I add more? If not, aright well, let me see if I can add more in the intensity, how do we do that? More reps more power. So yeah, you’re just constantly looking at, how do I adjust these couple areas to get the best overload possible?
Trevor Connor 10:05
The only thing I’m good to advise to be careful about is modifying the interval so much that you are now training a different energy system.
Ryan Kohler 10:13
So, this would be like a four-by-four VO2 max session, and we’re saying we’re going to now go to a four-by-twelve minute VO2 max session, which then is no longer,
Trevor Connor 10:22
A threshold session, training in the different systems. So, be aware of that.
Ryan Kohler 10:28
And we should also probably state that with recovery periods too, we can build in that and say, yeah, the recovery periods can change things pretty drastically. If you’re doing a four-by-four VO2 max with 30 seconds rest, well, that’s no longer going to be a great VO2 max. That’s going to turn into more threshold.
Trevor Connor 10:47
Exactly. Another really good example that I like to give is 20-second sprints. If you do a 20-second sprint and take a two-minute rest, that’s a true sprint workout. If you do a 20-second effort, take a 10-second rest, you’re now doing Tabata intervals, very different workout.
Basic Categories of Intervals
Trevor Connor 11:03
So, what Ryan and I are going to do now is go through some basic categories of intervals. We, as I said, any categories I’m about to talk about thresholds, we could show you 100 different types of interval workouts. So, we’re not going to try to explain every type, what we’re actually going to do is pick some of our favorite workouts show you those, but also give you some general principles on how to execute.
Threshold Intervals
Trevor Connor 11:26
So, I’m going to start with threshold intervals. I love five-by-five-minute intervals with one-minute rest, I tend to really like shorter threshold intervals of five-by-five minutes, four-by-eight minutes. My issue with longer threshold intervals, like doing 20-minute intervals is I don’t think you, it’s very hard to do and with enough intensity, unless you can find, for example, a weekly time trial that’s going on where you’re racing people and you’re really going to rip yourself apart. If you are doing these on your own as intervals, and you want to get to that longer interval type length, what I generally recommend is start with the shorter intervals, do them for a long period of time, get that power up using those, and then you finish it off with like 15 or 20-minute intervals for a couple weeks where you try to teach yourself to maintain that power that you’ve built for the longer duration, so I’ll sometimes do that with athletes. But what I’m showing you right now is an example of five-by-five-minute intervals. So, here you see my heart rate up in this graph up here. Down here, you see my power, the trainer was actually controlling my wattage, so you can see it’s just a flat line, I will also show you in a minute an example where I had myself control my power. But sometimes this can be nice, especially in the early season to just get a trainer that can control the power and just let it do its thing. When I do these threshold intervals, you can see this dotted red line is is my threshold heart rate, and I don’t really let myself go over that.
Focusing on Feel and Heart Rate
Trevor Connor 13:02
So, I set a limit of one beat per minute above that, my threshold I had set at 172, so I don’t want to see above 173. You’ll also notice that heart rate didn’t get there in the first interval, I’m actually okay with that I want to be pretty close in subsequent intervals. So, this particular case, I did the workout saw that I was a little too low on the first and the second, so I bumped up the wattage 10 watts, and that put me right in the right range to see where my heart rate was going to be. So, I don’t do these saying what percentage of FTP power do I want to use? Actually, what I do, and what I have my athletes do is there’s a certain rate of perceived exertion you want, I want to see your heart rate hitting threshold by that that ideally by the third interval or the end of the second interval, I don’t want to see your heart rate going over that, that threshold heart rate. So, whatever power gets you there is the right power for that day. And I had times as winter where on Tuesday, I did them and I was doing them at 350 watts, Friday, I wasn’t feeling great so I did them at 325, but the heart rate profile was always right. So, focus on the feel, focus on the heart rate, power is secondary. The right feel is you should do that all the intervals should be at the same wattage. So again, I don’t care what the wattage is, I just care that it’s consistent. And so, for that first interval, it should feel like, “That was hard, but it could have gotten a little harder,” by the final interval to hit that same water as you should be saying, “Boy, that took pretty much all I had.”
Ryan Kohler 14:41
So what kind of perceived effort system do you use with athletes in addition to this if they’re trying to develop that feel? Are there certain cues that you get them tuned into to know what that should feel like throughout with that first one knowing it’ll be easier and then by the end a little bit tapped out?
Sustainability and Learning Feel
Trevor Connor 14:58
So yeah, it’s exactly that. It’s that sustainability, I want athletes to learn, here’s the given length for my workout, I want to go at the intensity that I can sustain so that I don’t have much left at the end. So, if I gave them for example, let’s say we did something crazy, and I gave them eight-by-eight minutes, it’d be the same thing, something that you could sustain, but that’s going to be a lower wattage than the five-by-fives because the eight-by-eight is obviously a lot more time. So it’s really good as a time trialer to learn, I’m doing a 20 minute time trial, here’s what I can sustain for 20 minutes, I’m doing a 40k time trial, this is going to be 50-55 minutes, here’s what I can sustain for 50-55 minutes. So, to learn that feel so that by the time you get to the end, you feel like I pretty much gave it my all.
Ryan Kohler 15:49
And this is probably one reason why we do something like this around threshold for so many weeks like we saw on your yearly training plan 15 weeks of this, it takes time to work through those different five-by-fives, eight minutes, 10 minutes if we do some 20s, or even some longer ones to develop the feel for those different durations. It takes a while.
Trevor Connor 16:08
Yep. Yeah, I personally, I will give some of my athlete’s progression. I personally like just doing the five-by-fives all winter. Now, there are some coaches, and this is a discussion to be had that prefer to do thresholds during the season and something a little higher intensity during the base. I love the thresholds during the base season, because to see the full gains for these, to see the adaptations, takes about 12 to 14 weeks. So, really the only time you have the only period during the season or year, where you have that sort of time to give 12 to 14 weeks to set intervals is during the base season. But to give you an idea, so this year, I started my five-by-fives in December, I was doing them about 290 watts, I finished them up a week ago, I was doing them about 350. So, 60-watt increase, so it is big.
Trevor Connor 17:00
So just to show you a few more examples quickly, here’s the four-by-eights, this is from a previous year when I was doing them. This is one where I actually controlled by wattage. So, you can see not quite as flat a line, it does vary, but you can see I’m still keeping it pretty steady. This is just stupid. I was on Zwift, I want to get to the top and see if I could get the get the KOM jersey, shouldn’t have done that should have just stuck with my workout. But again, you can see the same thing here actually, on the final interval, my heart rate got a little over threshold, but you can see this was ideal. First interval I’m getting close to threshold and not quite hitting it. The second one, I’m sitting on it. Third one, a little bit over but still within my range. The fourth one was the dumb one, and this was kind of dumb, but this is where I realized I was on a good time for Zwift so I started breaking the rules, and that actually hurt me, this year I’ve been much more careful about that, but you can see the execution.
Trevor Connor 17:58
So let’s just look at a couple others. Here’s, again, five-by-fives. This is again where I controlled the wattage, I think I was outside, so you’ll see a little more variable, but again, look at my heart rate.
Ryan Kohler 18:13
Steady, yeah.
Trevor Connor 18:14
Pretty steady, you know, you can see here, I might have gone a little harder, I think I might have had a hill or something here, unfortunately, no map for this one. But still that trying to focus on keeping it steady, trying to get that heart rate on the right place.
Hill Repeats
Trevor Connor 18:30
Last one I’m going to show this is another type of threshold interval that I really love is hill repeats, and this is a big workout. This is the see how much you can do and crawl home a little bit which was this day for me. But I really like to give athletes hill repeats, where you go and pick a good steady hill that’s that steeper, 6 to 8%. I have them do it almost all seated. So, let me zoom in here on the hill repeats, so you can see relatively steady heart rate. This is a while ago, I have a feeling it was a little fatigued because you can see I wasn’t getting my heart rate really as high as you were saying in the other intervals, but the power was there. So, this is again, some of that adjustment. I don’t think I had heart rate fatigue, I wouldn’t have done the intervals if I was getting heart rate depression, I think this was a day where my heart rate was a little lower, so I adjust. That’s why you need to use RP power heart rate and make those adjustments. But you could see heart rate was very steady each day until the end where I would do a little sprint to the finish line. But the way I do these is you pick a start location, you pick a finish location, and that’s where you do your repeats and you try to hit the same time every time, and over here, you can see my times. Now, sometimes back then I’d get a little over-ambitious and try to take the first one a little too hard, I have a feeling that’s the case here, and yeah, you can see that. So, my first interval was 924, but after I got that out of my system, I calmed down a little bit, and here you can see second one 949, third one 946, fourth one 943, fifth one 940. So, you can see they’re all within 10 seconds of one another, and actually getting a little bit faster each time, which is something I like to see, these first five, this is what I tell my athletes to do is all seated, do not get out of the saddle until the very end, and then just sprint that last 10 seconds to get over the top. So, those are all seated, the last one is all standing. My old coach gave us those and he used to make us take our saddles out and throw them into the back of the car. I don’t do that, but it’s you do not sit down, I am not as fast standing, most athletes are not as fast standing as they are seated, so you can see my time was a little longer, but I was still doing my best to make it hard. That’s a good hard workout, and a great threshold workout. The other thing that’s a little bit nice about is you notice heart rate comes up really quickly, because you tend outside when you’re on a hill to get started, give that little bit of push. So, this is kind of giving credence to Ryan’s Batman intervals, which is that start a little hard, then come down, go a little hard at the end. So, this is this is a very similar to that bat, it looks like the Batman’s cowl or whatever you call it.
Ryan Kohler 21:31
Years coming up there. Yeah, yep.
Trevor Connor 21:34
So, I do a little bit of that when I do the hill repeats, and this is a great workout, very high quality, hard workout. I tell athletes when they do it, that consistent time is important. So, let’s say you do the first two, and you’re right around that 949, and then you do another one and you’re 1010-1015, you quit. I tell my athletes, you stop, you don’t continue the workout, you don’t have the quality anymore. So, it’s really important to try to hit that consistent time.
Ryan Kohler 22:02
And I like on these, they’re not exactly this is how many of six there, right? It’s not six-by-ten-minutes, It’s six hill repeats, and some are 943. Some are 940. So, this is a great example to show that we don’t have to get locked into this perfect workout of, I need six-by-10-minutes with three minutes rest in between, this has a little more variability to that on the climbs, but it’s still a very effective, high quality workout.
Trevor Connor 22:26
Yep, what do you see is I picked the same starting place, same finish place, that’s how I did my repeats. So, there’s a lot of different ways you can do thresholds, I showed you some of my favorites. I’ve seen a lot of different variations. But the couple things I really want to emphasize with threshold intervals are A, consistency, they should be the same intensity, you shouldn’t be doing the first one at 300 watts, and the last one at 225 watts. So, you can do hill repeats where you are shooting for the same time, you can do it by trying to get that consistent power, but they should be very, very consistent.
Intensity of Threshold Intervals
Trevor Connor 23:03
The second thing is you need to use all three metrics, heart rate, power, and rate of perceived exertion. But I will always tell my athletes heart rate and rate of perceived exertion, far more important than power. It’s whatever power is needed to get that right heart rate and right feeling of effort. So, one last thing to mention about threshold intervals is when you talk about intervals, there’s the question of how much time do you spend at intensity, and with threshold intervals I’ve seen some research on this, Dr. Seiler actually talked a lot about this, right around 30 minutes seems to be optimal. So, the five-by-five, that’s 25-minutes, four-by-eights, that’s 32-minutes, when I do a hill repeats there, they can be upwards of 40-minutes, but somewhere in that kind of 25-to-40-minute range is what is optimal. So, with that, Ryan, why don’t you tell us about HIIT work.
HIIT Intervals
Ryan Kohler 24:01
Alright, so we’re moving from threshold to quite a bit above threshold now. So, that that HIIT is this high-intensity interval training. So, we’re still talking about intervals, and this is going to mean that there’s periods of work time where we’re going for a certain duration, and in this case, we’re going to be well above threshold, and then we’ve got recovery periods built-in, and we’re just going to repeat those consistently, and there’s that consistency word again, we’re still looking for consistency within these intervals, even though they vary so much in the duration and the rest periods, we still want some of these key foundational principles to be maintained. So, I’ve got this one pulled up here. Starting this is probably moving I guess from your threshold to just a little above and then we’ll go a little bit above that and we’ll see how these, the times change and the intensity is change.
Training VO2 Max
Ryan Kohler 24:59
So, what were looking at here, this is one of my favorite workouts, this is four intervals of four minutes each in your zone five, or that VO2 max level. So, the goal with the workout like this is to do exactly that train that VO2 max, try to improve it, try to work at those powers that are going to elicit that number. So, compared to our threshold power, this will be quite a bit above that, in some cases. In some cases, it might be a little bit closer, but it’s there’s a range. So, this is one important thing for this type of workout is to again, know that it’s a range, If you have if you’ve done any, let’s say, for example, a MAP Test or you’ve done like that RAMP Test where you do these one-minute bumps up until exhaustion and you get a number that tells you your MAP, or that maximal aerobic power, that’s not your number. So, it’s gonna vary day to day again, but it’s the same process here, we want to have a starting point, know that on good days will be up around that, not so good days will be a little bit below it. But we want to continue that, that process of using the perception of the effort and the heart rate to achieve the workout goals. So, what we’re looking at here is you’ll see a lot of lines here, but let’s focus on this one here that has the nice color-coded bars, and you’ll see it goes it targets the lower intensities as green and then these higher intensities as red, and you can just see up here at the top, there’s a little bit of purple, which is that that top end, kind of that anaerobic power, right? So, what we’re looking at with a workout like this is four-minute intervals, which we see here, this first one that’s that’s marked off as three minutes, 58 seconds, that was auto marked nicely, and the goal here is to drive as much power to the pedals as possible over that four-minute period, but also the next couple of four-minute periods as well. So, this is where that consistency comes into play.
Ryan Kohler 26:58
So, leading into a workout like this, you can see a fairly long warmup period, we had about 26 minutes of warmup, and we did a couple efforts coming into a workout like this, because we’re going to be calling on maximal recruitment of muscle fibers, and we’re going to be tapping into that glycolytic system, and asking those fast-twitch fibers to do what they do and produce high force, then you can see here we’re kicking this off with a couple short sprints to really start to get those systems warmed up. So, once we start this, we look for a nice acceleration to get to that target power, power range, and then we’re going to hold on to it. If we bump up here to just the straight power this purple line, we can see it’s nice and light down in the one-teens, one-twenty, we start the interval, and we’ve driven it right up there 300 plus watts, and you can see it’s maintained very consistently throughout. One of the things that I like to do with a workout like this is take this first interval, and go hard, but make sure, as we said, with a threshold, you can still do more, right? So, you’re always going to feel pretty good on the first one for most cases, and the biggest mistake I find when we’re doing this type of effort is completely blowing yourself out on the first one, and then you’re cooked for the rest of the workout. So, sometimes with athletes, I actually think it’s valuable for them to feel that and achieve that failure where they do one or two intervals and they’re cooked, because well now you found that edge so now we can just work behind it in future workouts. So, we do that this particular one has a three-minute rest period in between, and you’ll notice with this compared to threshold intervals that we’re looking at before with shorter rest periods, this one because we’re now spending more time above threshold, we want to make sure that we can allow those energy systems to start to recover themselves. We’re also generating more lactate at this time, so we want to allow that lactate to start to be combusted and get that recovery.
Maximal Sustainable Power
Ryan Kohler 29:01
The goal here again is maximal sustainable power for each effort, and four minutes is a long time to go hard. So, we’ll see here just looking briefly through these. This one I got a little bit excited on you can see that second one, I must have been feeling pretty good on the first one and had a little bit more in the tank, so pushed pretty good on the first one got the power up a little bit higher. But quickly because I’ve done these a lot settled back in and tried to find that reasonable place, you can even see here, if we look at these colored zones, I went out a little bit too hard, actually came down and dipped in close to threshold there where I just couldn’t maintain that power. So, this interval wasn’t the best one, but it took me a little while to kind of get my way back up there and then finish off better. Then we see the third interval, fourth interval, pretty decently maintained, and then if we go back down here and look at the heart rate, you know, getting into the heart rate that’s one of the big focus points that I look at for workout like this is, how much time can we get that heart rate in roughly that 90% or more of maximum? So, I like to use that as a target to shoot for.
Threshold as an Indicator of a Good Workout
Ryan Kohler 30:11
Some days, I might find that I’m more like 86, 87, 88% of max, but as long as I’m above threshold, I know I’m getting a good workout. And like we saw with the threshold intervals, there might be some fatigue building in where heart rate might be dipping down a little bit, and it’s it’s not rising. Some days, I’ll still do the workout, but then I know I need rest. But if the heart rate is nice and responsive, then what we’re going to see is this nice increase, and just like we saw with the Batman-style approach earlier, that if we have this little kick early on, it’s going to help to drive that heart rate up, and we see this relatively level effort right here where the heart rate plateaus. But you can see as we go on, there’s a little bit more with this heart rate starts to creep up. So, that’s one of the differences that I look for in a VO2 max session like this is we might not necessarily achieve that perfect plateau, and we’re definitely not going to have that heart rate plateau around threshold. So, what we’re going to see is, as we fatigue during these workouts, that heart rate may start to just keep trending up a little bit indicating that, yeah, we’re above threshold, and we’re really digging, you know, digging ourselves a bit of a hole and really getting the overload.
Trevor Connor 31:19
I think that’s a really good point, and that’s something to look forward to your threshold intervals to. If your heart rates not leveling off, if you’re seeing that constant rise, that’s an indicator you’re probably not doing threshold intervals, you’re going too hard. So, you want to see that nice leveling, but if you’re doing something like what you’re showing here, what’s more, called these VO2 max style intervals, you do want to see that heart rate continuing up like that.
Ryan Kohler 31:43
Yeah, yeah, exactly. And that’s why when we have that high heart rate response like I said, recovery is crucial. So, let’s take this third interval, we had a bit of a strong finish here, and then right when it’s over, the power comes off, and we’re just hanging out and pedaling easy at this point, what, especially the harder we go in recovery periods, we don’t need to prove anything, we don’t need to produce power that’s too high, we just want to spin the legs out, continue that active recovery process, allow that lactate to get recycled, and then prepare for the next interval.
Functional Reserve Capacity
Trevor Connor 32:15
So, something I want to point out that’s important when you’re thinking about this high-intensity above threshold intervals, there is a you might have heard of something called watt prime, it goes by different names WKO, calls it functional reserve capacity, or FRC, but your threshold is the highest sustainable power, or the highest power that you can sustain. So, once you get above that threshold, the idea here is you’re on a timer, you have a certain capacity, hence the term functional reserve capacity of energy that you can use before you are depleted. So, now people call that your anaerobic capacity, not quite accurate, because if you just say 110% above the threshold, still generating a lot of that power aerobically, but you’re generating some power anaerobically. So, when you’re doing threshold intervals, that’s not really relevant, you actually want to be at an intensity where you’re not depleting that capacity. So, I’ll actually show you a graph, here’s my of those hill repeats that I showed you earlier, those are really hard hill repeats, I was feeling them by the end of it. This line up here shows the change in my functional reserve capacity or watt prime, and you can see is basically a straight line I wasn’t tapping in at all during the intervals, I’m not quite sure what’s going on here because that’s actually after the intervals, but during the intervals, not tapping into it at all. Let’s take a look at for example a Tabata style workout and see what’s going on with that functional reserve capacity line, and you’re going to see something very different. So, here’s a set of Tabatas that I did, you can see the heat map, that’s really high wattage. Notice my heart rate never got too high, because these were short intervals with quick reps. So, look at my functional reserve capacity. You can see it is just plummeting, this isn’t quite calibrated, but one of the things when you’re doing, especially these above VO2 max like your Tabata style workout, looking at that functional reserve capacity or watt prime could be useful if what you’re trying to actually do is depleted it. Dr. Tabata, when he invented the Tabata intervals, he was actually doing research on watt prime, and felt doing really hard four-minute intervals was just too tough to bring people into the lab to deplete that capacity. So, he invented these intervals as an easier way to deplete your watt prime. But it also turns out they’re a great interval workout and it’s one of the things when you’re doing these high intensity intervals, and I see it I believe your green line there.
Ryan Kohler 34:52
Yep.
Trevor Connor 34:52
And your screen is the same, you want to see that watt prime, functional reserve capacity, whatever you want to call it, you want to see that coming down.
Ryan Kohler 35:02
Yeah, I think it’s great you mentioned the Tabata style, because we see on yours, I mean that functional reserve capacity goes off an edge right off the cliff, and it goes right down to basically nothing, whereas here, these are the four-minute intervals, and you can see they do decline significantly, we’re at 12.9 here, we dipped down, we take out about half by the end, it recovers, and you can see it’s a pretty consistent decline throughout, but not nearly as steep as what we’re seeing with the Tabata style.
Trevor Connor 35:29
That’s exactly why Dr. Tabata embedded these intervals because they are a great way to just absolutely deplete that system, and I’m sure these intervals were killing you, you weren’t able to deplete it.
Ryan Kohler 35:41
Right, right. No. And at the end of this, I didn’t feel like I would after a Tabata-style workout either. These are still hard granted, but different levels of hardness.
Frequency of HITT Intervals
Trevor Connor 35:52
Yes.
Ryan Kohler 35:54
Yeah. So, talking about, you know, the execution of these, I think we’ve covered a lot of that. But how about the frequency of this? When we come to this level of intensity, I really try to avoid at most two of these per week, and that’s really when I’m doing a block of focusing on VO2 max efforts if I’m doing more of a mixed approach, or it’s in the offseason, where I might do a VO2 max session here, and then maybe like a threshold, or maybe it throws Zwift race in there, when I’m not very structured, you know, over the winter, then I’ll throw it in and it’s just fun. When it’s time to really work on this system, and this is something I’ll do, actually, I’ll be doing it coming up here soon to get ready for a spring race. So, I’ll do something like this, about four to six weeks out from the time I want to be ready to race, and that’s where I’ll pick two days a week, and these are the only hard sessions that I’ll do, everything else is built around that to be primarily aerobic and recovery-focused.
Trevor Connor 36:55
These intervals are really damaging, the more, the higher the intensity, the more damaging it is, and I agree with you completely, you need more rest. I can go out and do a good hard threshold interval workout, and then the next day go for a six-hour LSD ride. If I do a really hard Tabata session or VO2 max session, usually the next day is going to be a one-hour super easy spin.
Ryan Kohler 37:17
Yeah, exactly. Yeah, and then looking at when I’m done with these, one of the targets that I’ll check is how much time did I accumulate to know if I’ve gotten that overload? So, I’ll look at my heart rate zones here, and this aerobic capacity you’ll see here is really I want to get at least the time there, I want to hit that, because there’s a bit of a lag in the time that it takes heart rate to respond once power is applied to the pedals, this super threshold or zone five on this platform is also what I’ll use. So, I basically take this zone five and above to say, okay, how much time have I accumulated today, in that appropriate training level? So, same thing here, we can look at it a little bit differently, in this zone five, six, and seven, I can get a rough estimate of how much time I spent there and say, okay, was that appropriate? You know, when I’m looking at these kinds of workouts, I’ll be targeting around 15 minutes, maybe 12 minutes early on upwards of about 15 minutes for one session, and for me that that’s pretty adequate, we can certainly accumulate a little bit more. But again, like Trevor said, these are very damaging, so as you become a better rider more developed rider, and do this over and over, and you have the volume that can accommodate this, yeah, you might get more like 20 minutes, but that’s on the high end. So, there’s a fairly tight range here. Whereas threshold, or if we look at heart rate distributions for threshold, we can accumulate quite a bit more time, but as we get into this zone five VO2 max type of work that really starts to come down significantly.
Shorter vs. Longer Efforts
Ryan Kohler 38:52
Okay, so still on the high-intensity interval training, we were moving from four-minute VO2 max style efforts to now more of a Tabata style effort, where instead of four minutes, we’ve moved these down very, very short. So, like think 20-second efforts, and this will look completely different. So, if we look here at this first set, this is three sets of 20 seconds on 10 seconds off, this first set, you’ll see is very spiky, it’s just you’re on, you’re off, on, off, and we do that over and over again, and what we’ll notice is the heart rate response reflects that it takes a bit of time to initially rise, but then once it’s up there, it just maintains this sort of on-off approach all the way through. We mentioned this earlier that watt prime, or that functional reserve capacity, this is where we see us compared to the four-by-fours we’re not typically going to be able to deplete that. This one, because we’re just hitting the body over and over and over again, we see this continually drop just a little bit of recharge with those short 10 second breaks, but at the end of we’ll even halfway through the first set, we’re pretty well depleted. This one looks a little bit different because these were done outdoors. So, if you’re analyzing your ride, just be aware of doing them inside versus outside. So, this one had a bit of descent in it, and you can see that’s where I actually restored a bit more of that W balance, then we go through here and the profile is basically the same, by the end, it was getting right about down to zero by the very last one. So, big difference there and how these affect the body versus for longer efforts versus shorter efforts.
Tabata Style Workouts
Trevor Connor 40:31
So, a couple of things I will add, I’m a big fan of Tabata-style workout. So, that’s anything that’s short length, and you ever a rest period, that’s half the length. So, 20-10s, 40-20s, I’ve got a really nasty one over here, which is one minute by 30s, which really hurts. But there’s also you can do 15 by 15s, 30 by 30s, a lot of different types of variations here. One of the nice things is you can interchange them a little bit. So, you can see I built this giant Tabata nasty workout here, I never give my athletes this entire thing, but I might give them say, a set of 2010s, and then maybe two sets of 1515s, so you can kind of mix it up and make it a little more interesting, it’s all basically hitting that same system.
Consistency in HIIT Intervals
Trevor Connor 41:16
But the couple of important things to point out are you can’t do these by heart rate, because heart rate is never really gonna catch up. Also, really hard to do them by power, because if you’re staring at your power meter, you’re probably not going hard enough. So, it’s, you’re going again, for consistency, it’s just hit as hard as you can, but don’t blow up. So, if you’re doing 2010s, and you do a really hard one, and then 10 seconds later, you can barely start the next one, you went too hard. So, you do want to see some consistency, and so here’s an example of a set that I did, you can see, they do vary, but for the most part, the power is in about the same range, I didn’t look at power, I didn’t look at heart rate, that was entirely by feel because that’s the only way you can do it.
Ryan Kohler 42:02
That’s what I like about these there. It’s a fun workout because you’re sort of forced to look away from the data and just tune in with your body and go, and yeah, you find out pretty quickly, if the legs can’t turn over the gear, then we’ll take some more rest and try it again. But yeah, tunes you into the body nicely.
Ryan Kohler 42:17
Alright, so we’ve got our threshold, we’ve got VO2 Max, and some of those high-intensity intervals. What if we combine them what happens then?
Over-Under Intervals
Trevor Connor 42:25
Well, let’s talk about a fun interval called over-under, and this is where there are a million variations, there’s a ton of different ways you can do this. So, I get to just pound through a couple examples, but more just kind of give you the general concept here. The idea is you spend a certain amount of time above threshold, and then a certain amount of time below threshold, but it’s not a rest. So, for example, if your threshold was 300 watts, you do some time at like 323-330, but then the quote rest, the under is 270-280, so you’re still close to threshold. This simulates racing where you might do a jump, you might do an attack, but then you can’t take a rest, feels gonna keep going, you’re gonna be out the back if you drop down to 100 watts. So, it’s just learning that ability to go over threshold, but to keep going hard. So, I’ll show you a couple examples really quickly, and just how hard they can, be very quickly the one you’re looking at here, this is what I used to do that I’m not sure I can do anymore, which is four-by-two minutes, so four minutes well above threshold, two minutes just below threshold, that was just 24 minutes or 20 minutes, or whatever is, yeah 24 minutes of just absolute agony. You can see heart rate was going way over threshold, that took everything I have. I’ll show you a workout that Evan Huffman gave to us that I actually really like and sometimes gives my athletes he does this on hills, but this is just an example of some of the variations you can do. So, start with you do a climb for 15 minutes, just below threshold, then he had had you do three minutes just below threshold, two minutes just above for 15 minutes, then three minutes just below, one minute way above, do four repeats for 16 minutes, and then finish it out kind of like a race would, one minute just below, and then a 10-second sprint, and you just repeat that until you’re ready to puke.
Ryan Kohler 44:30
My legs are burning just looking at that workout.
Trevor Connor 44:33
This is a big, hard, tough workout. I rarely get my athletes all four of these, but it just shows you some of the variations you can do. He explains this as it’s kind of like in a race where you have four climbs, the first climb is just going to be steady, the second climb there’s going to be some attacks but not all out, the third climb is where it starts getting painful, and then that fourth climb is we’re attacking full sprints to get to the end. So, it’s a race simulator, that’s what over-under is about. There are a whole lot of different ways you can do it, just some thoughts on this, it doesn’t take long to get the adaptations. So, this is not something to do for weeks and weeks and weeks, consider this topping off the form right before you want to hit the peak of your race season, so I would say at the most, not four to six weeks, but four to six repeats of this type of workout. So, maybe it’s a secondary workout you throw in every once in a while when you’re doing Tabatas or the VO2 max intervals, or you just say, okay, I’m getting close to a target event, so for two weeks, I’m going to do this twice a week. But if you do it for too long, this is a sort of workout that can start pushing you into a non-functional overreach, so you really want to be careful with it. The other thing to really focus on when you do these is when you transition from that over to the under, no rest, don’t give yourself five seconds at 100 watts, it’s if you’re doing 330 and 270 watts, you go right from 330 to 270, and you can see that here with my workouts. There are no little green spaces here where I was doing a couple of seconds ago and easy, really focus on bringing that power right down to the target immediately.
Frequency of Over-Under Intervals
Ryan Kohler 46:19
Yeah, this is a really specific type of workout. So, for racing, this is perfect, and like you said, it’s if you do this too much, it’s almost like racing a couple times a week, and you’re gonna get burned out with that. I also look at this as a fun and confidence-inspiring way to have athlete’s train. Even early in the season, when we’re when we’re doing, say November or December where we’re not doing too much, I’ll use over-unders much, much lighter than this. But I’ll do it in a way where we might just touch on some tempo or some sub-threshold and just go between zones two and three, and that’s an easy way for athletes to sort of get some of that training load going, get some of the feel developed, and even coming back from injury, this can be a great way to say hey, let’s just give you a little bit more pressure, but then we’re going to dial it back while keeping things steady. So, I think it’s a very versatile way to train.
Focusing on Power
Trevor Connor 47:11
Yep. And so where I was telling you with thresholds really focus on heart rate, less so the case here because you can see with my heart rate, it doesn’t ever really catch up. So, this is one where you have to use power and focus on hitting those powers and being consistent about it. Notice how each of these above are basically the same wattage.
Sprint Intervals
Trevor Connor 47:33
Alright, so we’re getting to our last few interval types. Next one that we’re going to talk about is sprint intervals. I mentioned at the very beginning, that rest length can make a big difference where if you’re doing 20 seconds with 10-second rest, you’re doing a Tabata interval, if you do 20 seconds with a two-minute rest, you’re doing sprints.
Rest Is Key
Trevor Connor 47:52
So, when we’re talking to sprint workout, that rest is really, really important. So, you can see some sprints that I did here you can see I do them on a climb, I use about a 4 to 6% climb. I like that for two reasons, one is it means you don’t go too fast when you’re dealing with traffic so it’s safer, second thing is as soon as you finish that sprint and you’re ready to puke, you save just enough energy to turn around and just let the bike roll down the hill. So, if you look at my intervals here, these big red marks are the sprints. You can see almost no power in between them and it’s about a two-minute recovery in between each. If you go to track and watch a track sprinter, they’ll get on the track do their sprint and get off of the bike and lie on the grass for five minutes, then get back up get on the bike do their next sprint, and some of those guys they need to use a special chain because they put out such a big wattage, wattage, they would snap a normal chain. So, it’s big effort, lots of rest. That is the most important things with sprints, and this isn’t do the sprint and then cruise at 150 watts, this is as you can see for mine, it’s like try not to pedal at all, full rest to recharge that anaerobic system. When I give sprint intervals it’s generally somewhere 5 to 20 seconds, though you can see this first one that’s really fun, I actually do this workout where I do two 20 seconds sprints, three 40 second sprints, which is getting more into kind of an interval then a sprint, and then two 30 second sprints, all the rest of these are 20-second sprints. I do that just to build that tolerance, and these 40-second sprints are just the most painful thing in the world. Like I know I’m doing them right when I get to the top of the hill at that end of that 40 seconds and I am gasping for air like I feel like somebody choked me. Not a lot of fun, so unless you want that experience stick with the 20-second intervals. There’s a lot you can do with them.
Variations of Sprint Intervals
Trevor Connor 49:56
So, one of the variations I like which is what I did right here is do a gear cadence. So, since it’s on a climb I might start in a 3921, and completely spin out the gear in that first sprint, trying to go at a really high cadence. Next one will be the 3919, then the 3917, and the idea is you start in a gear that’s too easy, you go four harder, and by that fourth gear, it should be feeling like it’s a little too hard, I couldn’t quite get on top of it, you repeat that and go back up, and finish with the gear that you started with. So, it’s a, it’s a pyramid, that will help also give you that sense of what should the right gear feel like, because you’re going to find one of those gears, you’re going to put out the biggest wattage and that’s what you should be looking for when you’re setting up for a sprint. Another way to do it, which is what I did over here, this third set is big gear spreads. So, on the climb, I put it in the 5311, and I don’t think I ever broke about 45 RPM, and it’s just trying to grind up those spreads really it’s basically strength training on a bike. Another way some athletes particularly track riders like to do it is downhill, and go on for cadence, and see if you can hit 200 RPM. Regardless, however, you do it the right wattage is you are trying to hit the highest wattage you’ve ever hit every single sprint. This is not controlled this is how hard can I go? Ryan, thoughts?
Ryan Kohler 51:34
Yeah, there’s a lot of options for sprints a lot of ways to do it. And I think one big take-home is they’re quite taxing on the body. You can do it through more of a neuromuscular sense if it’s cadence, you can really generate a lot of force with big gear, and so I think it’s, yeah, being aware of what are you trying to accomplish first and go into a sprint workout with some kind of goal.
Trevor Connor 51:58
Yep. They are surprisingly tough, and you could see that a little bit when you look at my watt prime or FRC, you showed your four-minute VO2 max intervals, you never depleted it. I showed you to my Tabatas, it took an entire set of Tabatas to deplete it. Here you can see by the third sprint, I’m depleting every single sprint. So, this is a deceptive workout. It takes an hour, if you add up the total workout time, it’s not a lot, but boy does it rip your legs apart.
Ryan Kohler 52:27
Yeah. And a great technique practice as well.
Trevor Connor 52:31
Yeah.
Ryan Kohler 52:31
Well, because that’s the thing, I like how you’re looking at doing this on a hill, and also mentioned doing it downhill, you might do it on the flats, and getting a sense for that gearing is how your technique changes on a hill, versus downhill, versus flat, because it’s going to be different. And like we talked about getting our feel dialed in that perception of effort, it’s the same thing for sprinting too, knowing what does it feel like when I’m in the right gear? How much pressure should I feel on the pedals or in the legs? When I’m on the flat versus the hill to know, oh, I’m in the gear, I don’t have to look down I can just know.
Stain on the Body and Gains
Trevor Connor 53:03
A couple of other notes about sprints, again, very damaging workout and you see the gains very rapidly. So, it takes about two weeks, if you’re doing sprint intervals twice a week, it takes about two weeks to see the full gains. I never personally do them more than four weeks, and if I go longer than two weeks, I’m just gonna do them once a week. So, four or five sessions are all you need. Okay, Ryan, you want to tell us about neuromuscular work?
Neuromuscular Work
Ryan Kohler 53:31
Yeah, we’ll get touching on that. So yeah, the neuromuscular work, we’ve mentioned it briefly here with the sprints, but when we talk about neuromuscular work, I think of this as how can we start improving this brain-body connection, and there’s, there’s a lot to it, different ways we can approach it.
Cadence and Force
Ryan Kohler 53:51
Cadence and force are two big ones that we just talked about with the sprints, and that’s what we’re going to look at here. This is a warmup that we did a couple of weeks ago, and what you’ll see is really nothing very exciting here until we get into it, and how many minutes that is but we rode for a while before we started doing this, but the goal of a workout like this was really to prepare the body for something else. So, when we’re talking about neuromuscular work, I like to think about it as we’re preparing for something, we’re trying to get the body ready to do something else, and this is akin to even strength training. If we strength train off the bike, that’s neuromuscular work, we’re trying to improve how quickly we can recruit muscles, how many muscle fibers we can recruit, we can do that off the bike, and here’s a way where we can do it on the bike. So, looking at this workout, this was one that we did as an example for openers for a time trial. So, what you’ll see here is five different efforts, and very much like the sprints these are fairly short, so what we did coming into this one was, again, this is one example of many approaches that you can take for neuromuscular work. But what we did is we came into these at very low power, you can see here that you can actually barely see the lower end of that power range in the color band, but we lowered our cadence, we let the power come down very low, speed came down very low, and then when it was go time, it was everything we could do to accelerate the gear, accelerate the bike, and reach a top speed and a top power as quickly as possible.
Recruiting Muscles Maximally
Ryan Kohler 55:36
So, what’s the purpose there? Again, recruit those muscles maximally, and how many muscle fibers can we get to help produce that force? So, we do this, we’re going to, and you can see here, were deep into this purple top end zone here on this color-coded range, we finished our effort, we came right back down, and then it was very, very easy pedaling. And just like we saw with the sprint workouts, that took a good chunk of that, that watt prime away with it, and we do that every time. So, one of the hurdles I find when I’m working with athletes on this is that they want to go into these fast at times. So, one of my preferred workouts is slow speed. So, we start very, very slow, almost to the point where you feel like you’ll tip over, and then we have a large gear, a low cadence, and we hit this and it’s almost like the whole time it tells someone to think about pulling a rubber band, and we just keep pulling and pulling and pulling, and at that time when we say go, that rubber band snaps. So, all that pent-up energy you have now goes on those pedals, as if we’re trying to really just share the pedals off the crank. So, that’s going to be a high force.
Improving Technique
Ryan Kohler 56:51
I Also think about neuromuscular workouts in terms of technique where we focus on cadence, I ride a single-speed mountain bike a lot, and I love riding that for the technique work. It’s not always about force, other times it’s about cadence and being able to spin the legs really fast. So, when I’m commuting into work, there’s a great downhill and then a long flat where the speed is still high, and really, I’m not going to put much force on the pedals unless I’m pedaling at 180 or 200 RPM, so it’s a great place to practice, and I’ll take anywhere between like five seconds up to maybe 10 or 15 seconds, where I just spin as fast as I can, with the goal being keep everything generally relaxed, I’m not going to start gripping the bars really hard, I’m not going to start bouncing all over the saddle, but the goal here is really to say, how quickly can I get these legs turning to allow those muscles to be recruited as quickly as possible and teach them to coordinate? Get used to that coordination, where they can now spin smoothly and freely. So, the smoother we can do that, the better we end up doing when we’re on the road or on the trail, and I find that being able to have both ends of that spectrum that high force, and then also the other side, that low force and high cadence is very helpful in particular as a mountain biker, because I always apply this in different training scenarios and races where we’re on undulating terrain, where if I don’t have time, or I’m just not able to shift a gear to go harder, well, now I have another option, I can spin my cadence from 80 RPM to 115 if necessary, and now I can better maintain momentum. So, I look at these neuromuscular types of workouts as ways to improve technique and improve, improve my approach to training and racing and really help drive that performance a little farther.
Trevor Connor 58:43
There are a lot of different types of neuromuscular work you can do, which makes it kind of fun because you can constantly build different workouts and just keep it interesting. But I fully agree with Ryan, and this is where you train your muscles to fire on the right pattern. There’s something called coactivation, what you don’t want that’s where you have two muscles that are actually antagonists to one another, contracting at the same time, and that’s actually quite frequent because in the pedal stroke, there’s about I think there are over 20 muscles that are involved in that whole pedal stroke, it’s very easy to have to work against one another firing at the same time. That’s a lot of loss of power, neuromuscular training prevents a lot of that. It was very interesting, they did a study where they compared high-level cyclists to high-level triathletes, high-level cyclists do a lot of neuromuscular work, triathletes are notorious for not doing neuromuscular work, and you saw six times as much coactivation in the triathletes as you did in the cyclists. So, just riding your bike isn’t enough you need to do this. I’ll quickly show one thing here, I’m glad Ryan pointed this out, this is focusing on things like cadence, this is not your hard workout. We don’t show it all those other things, threshold workout, high-intensity work, sprints, that’s where you should be putting out your big wattage. There is some neuromuscular work, that should be hard, but this shouldn’t be your killer workout of the week, this should be much more focused on technique. So, here’s a neuromuscular workout that I did, which I’m sharing, you can see I was doing a lot of cadence work, right in the middle there, the green line is my cadence, you can see I did one of my favorite things, which is a cadence pyramid. So, I do a minute at 100 RPM, minute at 110 RPM, all the way up to 130-140, and back down. This whole workout, I averaged, I think 140 watts, 150 watts, if you look at the heat map of my power, I was never going hard. So, a lot of neuromuscular work, doesn’t require hard efforts.
Ryan Kohler 1:00:49
Yeah. And if we talk about, you know, frequency per week, or when to do this during the year, the nice thing about especially cadence drills like that is almost anytime, you can add this into recovery rides, to your base rides, you can do it as we saw in the example here as a warm-up to a time trial or another event, so these are things that you can add in almost any time you’d like.
Trevor Connor 1:01:14
Yep. neuromuscular work is also great, let’s say you fly somewhere, and you get on your bike, great first workout after a flight to get the plane out of your legs, also great if you take a big recovery Week and your legs are feeling flat, it’s a good way to help turn your legs back around before you do your first interval session.
Trevor Connor 1:01:32
Thanks for joining us for that somewhat in-depth look into intervals, believe it or not, that was still just touching the surface. So, we now have our interval pathway, highly recommend you go and look at that. We have deeper dives into many of these different interval types, we have some workouts that you can actually do yourself if you want to try some of these intervals. We also have a little more explanation of the pros and cons of doing interval work and the sort of gains you can get from it. So, we truly hope you enjoy both this video and enjoy that pathway. Thank you.
