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1| Cross-Training for Endurance Sports

Will O'Connor 0:00

Welcome to the first official episode of the performance advantage podcast with myself. Dr. Will O'Connor and Dr. Matthew Miller from MTB, PhD. Matthew, how are you doing?

Dr. Matt Miller 0:15

Thanks for having me.

Will O'Connor 0:18

And Mike Leishman, aka Kevin, has asked us about cross training.

Dr. Matt Miller 0:27

Ah, see. First episode, first shout out.

Will O'Connor 0:30


Dr. Matt Miller 0:31

Normally you built into the shout outs.

Will O'Connor 0:33

Yeah. Well, I guess we've sort of had a lead in from some of our previous stuff: cross training. I think this is gonna be a debate, to be honest.

Dr. Matt Miller 0:51


Will O'Connor 0:49

Well, I mean, when we talk about you know what.

Dr Matt Miller 0:51

Your intellect.

Will O'Connor 0:54

Yeah, okay.

Dr. Matt Miller 0:55

Okay. Well, maybe what we'll need to do is like, go over there and change your mind. You know how I mean.

Will O'Connor 1:04

No, I don't like the gym.

Dr. Matt Miller 1:06

Yeah, but you used to like the gym. Maybe you're just...

Will O'Connor 1:09

Yeah, I did. This is pre, pre endurance, Will O'Connor. Rugby and gym was definitely my game. Pushing the mass gainer. I definitely enjoyed that I got up to about 85 kgs. And Matthew?

Dr. Matt Miller 1:26

That sounds pretty big for you.

Will O'Connor 1:32

Yeah, it's about 10 kgs heavier than I am now. I've gotten... I found some photos the other day. It's pretty crazy how everybody changes? Matt, why are you pro gym, if we're talking about cross training?

Dr. Matt Miller 1:49

Well, there's lots of reasons why I'm pro strength training. And, the main reason is, because when you do like a really, really hard, heavy lift, you're creating these new neuromuscular junctions to these muscle fibers you already have. So, these muscle fibers are already there. So, if you're doing a squat, you have all these muscle fibers. And a lot of them you're not actually using, you're just kind of using the ones that you're using to bike or run. And there's some other ones in there that aren't being used. When you do a big heavy lift, the one of the very first adaptations that happens from strength training, is you get these new, neural pathways to use these muscles. And that's really good, if you're trying to produce more power, or run faster, or by car,

Will O'Connor 2:37

Would you not just do that on the bike? Or more running or whatever? Why are you specifically needing the gym for that?

Dr. Matt Miller 2:49

Well, because doing a one rep max, or a five rep max squat is way different than, you know, jogging up a hill or pushing a big gear. I consider those endurance training. And strength training is just a different thing that you can't do while you're doing endurance training, in my opinion.

Will O'Connor 3:10

So then, you can't do it on the bike, right? That's sort of understandable, because it's not load bearing. You can't exert enough force in order to recruit that large amount of muscle. So my argument would be just because you train those muscles under load, under weight, like doing a squat; how does that translate into you being able to use them on the bike, if you couldn't do that work on the bike, anyway?

Dr. Matt Miller 3:44

That's a pretty good point. I don't really have an argument against that one, that's a pretty good one. But if you need to do a massive, massive sprint, or you need to start to produce more power, just having those muscle fibers available, ready to use where they weren't before is enough. Because, if you want adaptation, you need to push beyond what you're currently doing. And if your thresholds at, 300 watts, by riding at 320 watts, isn't going to make you create new neural pathways necessarily. It will up to a certain point, and we see hypertrophy, which is the building of muscles that happens in endurance athletes. It's not just for people who spend time strength training, and then it kind of stops because you're using type one muscle fibers, right? Predominantly, we want to use those type two muscle fibers.

Will O'Connor 4:42

Yeah, or type two. Type two, is generally what? So when we say type one, we're talking about aerobics, slow twitch, and then we'd say type two, we're talking about fast, glycolytic fibers which are predominantly high force, very inefficient fibers. Then there's sort of this type two x, which can be, I guess, molded into the type of fiber you would most need it to be. So that's what you keep training long, slow miles, they'll probably get very mitochondrial dense and become very efficient, great at burning fat, and utilizing oxygen. If you're just smashing 10 in the gym, then they're probably just going to build on themselves and remain relatively inefficient.

Dr. Matt Miller 5:32

So we also produce a lot of force.

Will O'Connor 5:35

Yes, lots of force. Yeah. So, there's a juggling act, right? Where if I was to use gym, for endurance, the way I tried to use it for myself was during the boot up to my first ultra marathon. I thought, the main gains I need to make is underload. Because it's not running the 40 to 50 Ks, that's a problem for me it's the running 80 to 100 Ks. And you can't do that in training otherwise, not that you can't do it in training, but you're most probably not going to, because you'll just wreck yourself. So I figured that putting a large amount of weight on my back and squatting it would then recruit those muscles that otherwise, I would have to run for five hours to rely on. If that makes sense. Spatial recruitment principle. You know that.

Dr. Matt Miller 6:36

I don't know that one. I should, because I taught muscle mechanics postgrads last year. I don't think we covered that so I don't remember.

Will O'Connor 6:43

Really? The spatial recruitment is essentially like, the greater the force, the greater the recruitment of muscle fibers. So when you're walking, you recruit. If you had 100 units of muscle, you would recruit the same number 1 to 20. Every time you get out the door, 1 to 20, 1 to 20. So if you need an overload, you need to go one to 25. And as number one to five start fatigue, you start to then rely on number 20 to 25. And then if you started to run, so you went from a walk to a run, you now start to recruit numbers 20 to 50. So that spatial recruitment is the same recruitment pattern every single time until the point where you recruit the fly number 100. Now, doing aerobic exercise, you're never going to get to that point. Whether that's absolutely necessary is arguable. But if you can at least train those fiber types, number 50 to 70, say that, which I would hypothesize is around a type two X. If you convert those to more aerobic that has still high force base fibers, then you should be able to generate a lot of force right at a high power. So I'm at a fast pace run at a fast pace. They still do it relatively aerobically. Ergo here's a quick refresher on your course.

Dr. Matt Miller 6:49

There you go. Thank you. I knew that one. Yeah, yeah, I see what you're saying.

Will O'Connor 8:16

Look, I'll have to refresh it myself. But that's the fundamental principle behind it.

Dr. Matt Miller 8:20

Right. But you're saying it didn't work for you? Is that what kind of what you're telling me?

Will O'Connor 8:24

No, I'm not gonna say it didn't work. I'm sorry. I didn't like it. I didn't noticed like this dramatic improvement. Now in swimming, that's a different story. Because you cannot apply enough force on the water. The water, as a medium, is not dense enough. And there's no gravity whatsoever. So in order to overload your muscles to generate force, it's like impossible. I did notice when I tried gym for swimming, I definitely got a lot of improve--, not a lot of improvement, but an increased amount. But then when I think about cross training, I'm like, geez, we're already trying to train for one sport. Why do we need to throw everything else in?

Dr. Matt Miller 9:15

Yeah, well, gym only one thing that you can do. And I don't like to call it gym. I like to call it strength training. Because gym is something that someone says when they don't do it.

Will O'Connor 9:25

I like the gym. Not the gym. Yeah, like the gym. I run on the treadmill.

Dr. Matt Miller 9:34

Well, they have TVs now. So that's pretty good.

Will O'Connor 9:37

Yeah, magazines. Get on the recumbent bike. Is that what you guys do at the gym?

Dr. Matt Miller 9:42

Yeah, pretty much.

Will O'Connor 9:43

We're kinda cycling.

Dr. Matt Miller 9:45

Yeah, I'll tell you my favorite workout to do in the gym is potentiated plyometrics, where we'll do something like a really, really heavy squat, two times, and then immediately when we run, the barbell will turn around. And we'll do two really quick plyometrics. And even though you're only doing four movements, that's just an amazing exercise. That's one set. And we'll do like three, three to five sets.

Will O'Connor 10:15

Why are you doing it?

Dr. Matt Miller 10:17

Well, because what we want to improve is power, right? And power is something -- that's plyometrics, where we're producing a lot of force really, really quickly. So but you know, what we can do is something called potentiation, where we kind of, we prime these muscle fibers and have them ready to go to do this really, really powerful movement. We do that by doing something like a really heavy squat before doing plyometrics.

Will O'Connor 10:42

Yes, right. So post activation that tension muscle potentiation is well documented in the literature. So that sort of like, it definitely works.

Dr. Matt Miller 10:52

So you definitely do that in the gym.

Will O'Connor 10:55

I know. I don't go to the gym.

Dr. Matt Miller 10:56

Ah, okay. Okay, so what do you do for cross training then?

Will O'Connor 11:00

Well, that's a hard one. So at the moment, I'm predominantly focused on running and marathon and up, currently training for a marathon in two weeks, I'm doing mountain biking for my cross training. Especially with running in single sports, I'll try to get athletes to incorporate something else. Otherwise, depending on the time availability, it allows for, running especially, you can only do so much because of the loading before you inevitably get injured. But like 10 hours of running is a lot of running. But then it's not a huge amount of time across the week. So like myself, I can train probably around 15 hours, just available time and energy wise. So that means I get out on the bike, the mountain bike a bit. One because I enjoy it. Two, it helps energy expenditure and weight maintenance. And then three, it's a specific cardiovascular, aerobic, and also has some, like, eccentric loading in there.

Dr. Matt Miller 12:14


Will O'Connor 12:14

Yeah. And then with triathletes, there's no time. There's no time to try and

Dr. Matt Miller 12:21

You're pretty much are a cross trainer.

Will O'Connor 12:23

Yeah, you're a cross trainer. You're like official exerciser. So with that? Cross training, not so much like we would put in some band work or muscle activation work, but nothing. Nothing specific. Are you choosing to do something completely different at all, like, stand up paddle boarding?

Dr. Matt Miller 12:48

I've never tried. Honestly, I don't touch anything near the water. So yeah, like someone else can do that. If someone's interested in it, then they can keep doing it. But I'm not really sure. Since I've never done that, I can't quite think of how the muscles would kind of work.

Will O'Connor 13:06

I just use that as an example. Like, you what are you doing?

Dr. Matt Miller 13:10

I think like, so if I'm working with a mountain biker, I don't consider road cycling to be cross training. Because that's pretty much what they're doing is they're training to be better at pedaling usually. So I've can, you know, I consider strength training, and road cycling to be just pretty much part of what mountain bikers need to be doing all the time. But some different things that they could be doing would be like hiking, or just straight up walking. A little bit of running, but you need to be careful with running if you're not used to it.

Will O'Connor 13:50

Yeah, running is just just the worst kind of sport to get in. To start it, like once you have built up your tolerance and your lower lung tolerance to training loads, then it's not so bad. Try running again is not as bad become some sort of risk there. But running like I wouldn't, I would not recommend cyclists to running. They all try and do all the roadies try and you know that they're having their time off. After one day, you feel like the fair bastard from Austin Powers. So yeah, that like they'll do like these 20 k runs straight off the bat.

Dr. Matt Miller 14:35

First run back.

Will O'Connor 14:31

Yeah, like the next week and they're in good break?

Dr Matt Miller 14:35

Ready to get back into training now? Yeah. Oh, you're not. You need to like rest.

Will O'Connor 14:40

We have leagues for the last five days. So not with the road cyclists. But then if we go down, across to your more everyday athlete. Often they think that gym, strength training is quite important. These people generally have, you know their time isn't as flexible as is yours, Matthew. They may have fixed nine to five or some other kind of work structure. And then they have that just that other general stresses of time stress. So if they want to they want to run a half marathon to marathon. What are you recommending?

Dr. Matt Miller 18:07

Well, I think if someone has really limited time, I think if they do strength training, one of the things that they can do on the times when they need to be taking a break from their aerobic exercise, is that they can be maintaining energy expenditure at a really high level by just switching the muscle groups that they're using. So for a runner who, maybe really need to lose weight but they can't run every day, then on the days that they can't run, they can be doing a really hard upper body workout. They're not going to have huge increases in mass in their upper body by doing a really hard upper body workout, especially if their main focus is running, because they're just not going to be able to build the mass really,

Will O'Connor 16:23

How does that work with the aerobic development and the stress like this? It's a reasonable amount of physical stress, like a hard gym workout? strength.

Dr Matt Miller 16:36

Stress strength training. Yeah. It would be like I wouldn't like add in. If someone's trying to get better at running, they can't run a whole lot, because they just actually can't handle it. I wouldn't really add in any lower body strength training on top of running. Maybe instead of some running workouts, especially if they can only run 30 minutes before they kind of crack. If you know they can only run 30 minutes a day, for a week, maybe what we need to do is have them do a really big gym session with where they'll have massive energy expenditure in the same amount of time.

Will O'Connor 17:15

Well with running and energy expenditure along these lines, I think we could broach the subject of weight. Endurance sport is powered weight, where essentially the lighter you can be without losing muscle, and the more efficient you're going to be, the faster you're going to go. Running is a huge one for that because of the weight bearing nature of it. So you want to know what kind of workouts you're going to be prescribing. If this person, for whatever reason, due to injuries, maybe their weight, they can't just run and you've got them in the gym, then definitely don't want to build muscle and probably due to the nature of them, they have a predisposition to building muscle. How are you going to structure it? Are you doing high reps, or low reps?

Dr. Matt Miller 18:07

One of my favorite things to do because of the feeling that it gives you. Like in an upper body circuit, because it's kind of aerobic and you get really sweaty, and you're still moving around a lot of weight. So you're still doing quite a bit of work.

Will O'Connor 18:23

You look embarrassed.

Dr. Matt Miller 18:26

You look sweaty. You look cool, right? When you're gymming right. So, an upper body circuit is pretty good with probably like six different workouts, different muscle groups, but push-pull kind of thing with a different muscle groups. Six exercises back to back to back to back to back. Then a short little rest something like that. And you do three sets of that.

Will O'Connor 18:48

Yeah. Okay.

Dr. Matt Miller 18:50

Yeah. That's pretty good. And then you can add some, you know, something really heavy probably before that, and then, finish the circuit. That's a great way to go. And if you're using all these muscles, that's quite a lot of movement, and quite a lot of mass.

Will O'Connor 19:08

Sorry, can you show us those muscles again?

Dr. Matt Miller 19:11


Will O'Connor 19:11


Dr. Matt Miller 19:12

Not gonna. No.

Will O'Connor 19:13

I know. We miss. I missed them.

Dr. Matt Miller 19:15

Yeah, that's right. Yeah, not when we're live. Maybe later.

Will O'Connor 19:20

Yeah, thanks. Ah, right. Okay, so you've got a pretty harsh sort of circuit workout within. How long they're going to take?

Dr. Matt Miller 19:31

You can usually bang out just the circuit in about, 20 to 30 minutes. And you can do it at home, right. Like, there's some that you can do at home, which is really good. Because not everyone wants to go to the gym. You know?

Will O'Connor 19:48

Yeah, yeah, no, definitely. So just a matter of grabbing some frozen water bottles or something like filter sand or something. Yeah, that's gonna allow at least It's a bit of load to be here and there.

Dr. Matt Miller 20:05

Or maybe buy something but sand will do. Yeah. So what what kind of cross training do you think's really good?

Will O'Connor 20:14

Oh, look. I'm just not enlists the athlete specifically enjoys I had one athlete recently and they really enjoy CrossFit. So as you know, like CrossFit is extremely taxing on our adrenal system. So trying to structure that, and within an insurance program is quite hard. But otherwise, I'm not really recommending it. I'm designing a program that I think can have them exercising aerobically more often. That depends on the mentality of runners, or even triathletes who need a run, I deal with the run, walk. So you're getting in enough of a time wise, durational and long distance, but you're breaking the running out with small periods of walking. So if you can get your head around it, it allows that 30 minutes of time where you would normally break down to extend into an hour with 40 to 45 minutes of total running time. That's more how I go about it unless someone specifically wants to get into the strength base side of things.

Dr. Matt Miller 21:40

So can I talk about my favorite cross training?

Will O'Connor 21:46


Dr. Matt Miller 21:47

Because we kind of mentioned it before. And I think just hiking and just walking is just great. It's just great.

Will O'Connor 21:56

By 100%, I try and implement that in as well, especially for marathon runners and ultra runners because the majority, average time for a marathon is gonna be four or five hours. And it's sort of a catch 22 because if you're taking that average amount of time, and then an ultra, it's going to be around 15 to 17 hours. You also answer as well trained as the people who are taking a far less amount of time The professionals are taking two to two to two and a half hours, and you're running the exact same race in four to five hours. They obviously can bang out a very hard session in three hours, which is over what they need to achieve. But then for you to go out and try and run four or five hours every weekend. You just can't but then, you're having to hike or tramp or whatever you you want to call it. You're generally carrying at least two to three kgs. And you're ascending and descending, which just exact exaggerates the load you're putting on your legs to what you'd have to do in the race, and you get tired and sloppy and extend your your stride length and stuff and put more impact through.

Dr. Matt Miller 23:24

Well, I still feel it.

Will O'Connor 23:25


Dr. Matt Miller 23:26

Yeah, definitely. But I think it's really good. Because when I am talking with an athlete, or trying to think about what kind of training we can do to improve their fitness. I'll kind of try and think about what's going on actually inside of the muscle. Right? And normally what we need to do, what we want to do normally for someone doing some sort of aerobic exercise, or even some sort of repeat sprint, is we really want to like increase the mitochondrial density, and we do that through doing low intensity, repetitive exercise, and walking is great. So even though it's different muscles. It's still enough of the same muscles, and you can use them for a really, really, really, really long time at a really low intensity. And I think it just complements a bike training, a cycling training, or a running training program. Just really, really good.

Will O'Connor 24:24