Most cyclists can produce more power riding outdoors than when training indoors. In this episode, coaches Neal Henderson and Mac Cassin look at the reasons behind this discrepancy, including how the way you ride outside can help identify specific weaknesses and areas for improvement. Learn More: https://www.wahoofitness.com/blog/ask-experts-indoor-cycling-power-vs-outdoor-power/
As the northern hemisphere starts to hear the first whispers of spring, cyclists' thoughts turn to riding outside. If you’re training outdoors with a power meter and this is your first time doing structured workouts outside, you may notice a difference in your ability to sustain power out on the road versus on your trainer. This isn't in your head. Most cyclists can produce considerably more power outside. In this episode, Wahoo Sports Science coaches Neal Henderson and Mac Cassin look at the reasons behind this discrepancy, including how the way you ride outside can help identify specific weaknesses and areas for improvement. Get out there.
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Hello and welcome back to another episode of the knowledge podcast by Wahoo, I am Neal Henderson head of Wahoo sports science.
Mac Cassin 0:31
And I'm Matt Cassin senior sports scientist, they are going to talk about some of the differences we see between indoor and outdoor power output and a few of the primary causes for those differences.
Neal Henderson 0:43
Mac powers power, right. I mean, is what is an indoor watt, not the same as an outdoor watt?
Mac Cassin 0:50
That's a pretty loaded, loaded question there. Neil. I
Neal Henderson 0:53
know I set you up. Sorry.
Mac Cassin 0:55
So in some ways, yes. In other ways? No, what we'll say is it depends. Hashtag. That's copyright. By the way, no one else is
Neal Henderson 1:06
allowed to use that. Okay, I'll try not to.
Mac Cassin 1:10
So the difference is between indoor and outdoor power. There's, there's a few different factors here. And those basically break down to those are the physiological factors. There are psychological factors. And then there are factors like equipment. So.
Neal Henderson 1:25
So in that way, it's your ability to generate that power that is affected by those things. But, an indoor watt is still equal to an outdoor watt, right? Yes. Okay. Watts, or watts,
Mac Cassin 1:40
unless the cadence changes, but we've got a whole other episode on that.
Neal Henderson 1:43
Definitely. Yeah, you can check that one out. All right. So when we talk about these physiologic aspects of power production, and the variation that we see or differences that we often see between indoor power generating capacity and outdoor power generating capacity, are what are some of the key things that you think about the back?
Mac Cassin 2:03
So one of the big ones that I think a lot of people will actually feel in some ways when you're indoors on a trainer, you're the bikes locked in, it's not moving underneath you. So the general alignment that you're going through as you pedal is different. You see some people again, boy, it was the best example of this, you know, he would when he was going hard, he'd weave back and forth, quite a bit. Yeah, some lateral movement, right. And that's really to, you know, get the alignment between hip knee, ankle pedal, it changes a bit when you can rock the bike back and forth. And so without that change, you know, the biomechanics are a little bit different. Now, that's not necessarily the case on something like rollers. So some people prefer rollers for that reason, they're a bit more comfortable, we have a whole episode going into the different types, of trainers and whatnot. But it's, it's a really fascinating problem if you actually look at the physics of it. Because even like just how a bicycle stays stable is still one of those, quote, unquote, like Unsolved Mysteries of physics, where, like, we don't fully know how it works, but suffice it to say it's more complex than just allowing a bike to rock side to side.
Neal Henderson 3:15
Yep. Though, having a little bit of movement may be a nice thing. For your indoor setup.
Mac Cassin 3:21
Definitely, it can make it for me, it's, it's a big difference to make it feel more comfortable, less, less, less static
Neal Henderson 3:27
and locked in. Right. Okay. So yeah, I can definitely see that like, out of the saddle sprinting, especially, but even at you know, moderate effort steady-state, you would definitely still see a little bit of more side to side movement, generally outdoors than you might see indoors. And so that might impact the amount of force and power that you're able to put into the pedals.
Mac Cassin 3:50
Yeah, and that's a great point, like out of the saddle sprinting, that's probably where you'll see people see the biggest difference if they are looking at power indoors versus outdoors, you'll probably see, you know, you can see upwards of a couple 100 Watts difference indoors versus outdoors.
Neal Henderson 4:03
Yeah, definitely. And actually, we did a little bit of assessing a few riders and a couple of us both our indoor and outdoor ability to produce power at basically what we use for our full frontal test. Protocol, five seconds sprint, five-minute effort 20-minute effort, one-minute effort maxes out all of those. We did it both indoor and outdoor within one week, just to see you know, how much variation there was, and it seemed like there was less difference around say FTP, the 20 Minute type of value, a little bit more at a map, continued increase difference at AC and the most difference definitely occurring in that neuromuscular kind of five seconds sprint power.
Mac Cassin 4:43
Yeah, so essentially, if you're doing a workout outdoors and you have specific power targets, basically the higher those power targets are supposed to be indoors, you know, there's going to be a larger variation when you go and try and do those outdoors.
Neal Henderson 4:57
Yep, so you would not recommend using them What you've done outdoors to set your targets as you train indoors,
Mac Cassin 5:04
right? Absolutely. And there are a few other reasons that we'll get into when we get to the equipment side of things. But yeah, definitely, it's the same as you know, if you're testing on a road bike, and then doing all your training on a TT bike, there's going to be the difference in power output. So you really shouldn't do intervals on your TT bike based on what you did on the road bike,
Neal Henderson 5:24
for sure that specificity of position is important. And something that relates to that as your core strength, stability, flexibility position on the bike, even say, like, doing an effort in the drops versus sitting up on the tops on a road bike, you often see some differences there, right?
Mac Cassin 5:41
Yeah. Some of the, you know better time trials in the world who you might have worked with from time to time, you know that there are some people who there's very little difference in power there. And then you have other people where there's a massive drop-off in power just from that slight change in position.
Neal Henderson 5:58
Yeah, I would say on average, most people produce less power in a time trial position compared to what their ability to generate power in a road bike is so most people always say like, well, how much? How much less Do do you produce in a TT position compared to erode position? Well, it's really variable. And individuals like Evelyn Stevens, like Rohan, Dennis, like Cameron die, who's retired now, but professional triathlete very, very successful at nondrafting races and TT position, they all hit their highest peak power is actually even Taylor Phinney hit their highest peak power for many, many durations, longer type things, five minutes, 10 minutes, 20 minute, hour, etc, in a TT position, compared to on the road bike, because the specificity of what they were training for, where their goals were, and they were set up to be able to generate power in those positions and go fast. Some others who, you know, don't have that time trialing as their focus, well, we might see, you know, generally a five to 10% lower power and in some cases, extreme drops a 15, or 20%. In a TT position, if somebody is not positioned well, or if they are truly a, you know, climber who loves to get out of the saddle a lot. And just the position that they can generate power compared to what they do in a fetal position could be so variable, and those differences will clearly be impacting indoor and outdoor how they ride.
Mac Cassin 7:24
Yeah, I think another really good similarity there between the, you know, the differences you see on a road bike versus TT bike that and how they apply to, on the trainer indoors versus outdoors is that core strength is stability, again, that wobble back and forth not just isn't just for explicit alignment of your legs, but it also has to do with what is the backboard your legs are pushing against, if you have a weak core, you're going to be prone to wobble back and forth a lot more often. And so, again, because on a trainer, you're fixed, that lack of core and you need to rock when you're outside, to give that good backboard to push against once you're locked in on a trainer. If you have a weak core, you're just going to essentially bleed out power.
Neal Henderson 8:09
Yep, that'll be exploited there. Yeah, interestingly, I've seen some really high-level athletes at that limit where they're pushing as hard as they possibly can. And they still have the really good output that sometimes you see more of like a salmon where they're going side to side kind of wiggle. And then we have others that are kind of having this forward, backward rock. And so it's kind of interesting that you know, where that where the mechanics start to break down, while an athlete is still producing a lot of power can definitely vary. And so there's no one perfect way of doing things, for sure, right, based on your strengths, weaknesses, etc.
Mac Cassin 8:45
There's no perfect way to do it. But there's probably a number of wrong ways to do it
Neal Henderson 8:50
a lot of wrong ways. Definitely, I've done most of the wrong ways. And so
Mac Cassin 8:53
with that, you know, if you find that you have a really big difference in indoor-outdoor power, maybe, and you have been lacking on your core or stretching, you know, it's not gonna hurt to do either of those things. And it might help with that improvement.
Neal Henderson 9:05
Yeah, and I do find doing indoor training sometimes allows you to focus on that position, even more so than you might outdoors. And so being able to think about engaging core, especially like to say, transverse abdominus, and being able to belly breathe, all of those things are things that you can concentrate a little bit more in the indoor training that then when you go outside, you have maybe some cues that you can be like, oh, yeah, engage and just, you know, kind of click into a little bit better mechanics and be able to potentially produce more power even than when you're outside.
Mac Cassin 9:35
And not to continue to harp on the time trial, but I think you and I are both a bit biased towards it. But even that, as you know, positions these days are quite extreme and aren't really safe to do out on the road necessarily. So again, the trainer, you know, it's a good time to practice you're keeping your head tucked, being able to see enough for a close racecourse that you might otherwise you wouldn't be recommended on open roads.
Neal Henderson 9:57
Yeah, definitely. I'm definitely a fan of positions where you can see is still being an important factor for success over time. So we can train effectively as well as race effectively at that. But definitely, it takes to take some time and the indoor environment provide some benefit, where we can work on that position to improve them that ability to produce power when we go outside.
Mac Cassin 10:18
So what's the, what's the other big one for that? Just from a physiological standpoint?
Neal Henderson 10:24
Yep, heat. And when we ride a bike wheel, we're only you know, say 20 to 25%. Efficient, right? Generally, in terms of internal work, our body does, what actually ends up going into the pedal. So if I'm pedaling at 200 Watts, as my power meter reads, My internal work total being done is somewhere you know, closer to 800, maybe even 1000 watts of total work being done 200 That going into the pedal, so the rest of that is predominantly released as he heat production. So pretty high efficiency that might be 600 watts of heat being generated at that 200
Mac Cassin 11:04
Watt output. Just like just having a toaster just sitting inside you crank
Neal Henderson 11:09
it exactly. And just think if you had that toaster oven sitting next to you putting the heat into you, you'd probably feel not so comfortable. The same exact thing happens if you're sitting on in on a trainer indoors and don't have any air moving over you, which is known as convection.
Mac Cassin 11:28
Right? So that yeah, that's the big thing. Since you're not actively moving through the air, there's no wind going over you. And it's also the same with climbing you can the speeds are lower, you're working very hard. That's why you can overheat quite easily. That's one of the things that's been most fascinating to me about Miguel and Duran. And regardless of some of the methods that might have been going on at the time. He was a big dude and like 80 kilos, putting out like 500 Plus watts on climbs in the tour, you know, granted, he's going pretty fast. So there was some wind, but you know, that's capitalistic, 2000 watts of heat being produced that he's having to mitigate. Wow, going slowly, in a French oven, essentially going up a climb. It's just that to me is just mind-boggling.
Neal Henderson 12:14
Yeah, absolutely. Especially if you've ever gone up a climb and you have a tailwind. Man for like summertime here. Sometimes we get upslope winds and going up a climb like say lefthand Canyon, putting out a lot of effort like going as hard as you possibly can with a tailwind is like it just sweltering. I know, the external world championships in Maui. One year we had a tailwind going up one of our steeper climbs that I mean, it's 80. Some degrees, I think the humidity is in the 80%, the sun is beating down. And I honestly had to slow down. And the first time I had water, there was a water break partway up, I grabbed a cold bottle of water and just poured it over my head. And that made all the difference in the world for about two minutes before that night the heat was was back in the water was empty. Yeah, it helped temporarily,
Mac Cassin 13:04
right. And so that heat buildup becomes a problem because what your body wants to do, it wants to cool down for safety, it doesn't want the internal temperature to get too high. And one of the main ways it does that is it starts to divert more blood to the surface of your skin. That's why you'll get flushed like red if you get overly hot. And so that blood is then going into your skin instead of towards your muscles, your
Neal Henderson 13:26
your working muscles carry that oxygen and those fuels are being distributed across your entire circulation, not just the working muscle. So that means that working muscle gets a little bit less to work with a little bit less fuel a little bit less clearance of byproducts. And hence output will be reduced.
Mac Cassin 13:45
Right. And that actually leads right quite nicely into the next component. But one of the things that excess heat causes is it causes your rate of perceived exertion for a given effort to increase. And so that's where the psychological component of indoors and outdoors becomes another factor here. And honestly, sometimes it just feels harder to ride indoors than it does
Neal Henderson 14:08
outdoors. Yep, there's less distraction when you're indoors for the most part now yeah, you can like to crank up the music, you can, you know, get a screen with something interesting in front of you, you could be doing a workout that has a bunch of stuff. But still, comparatively, the relative distractions that you may have in that indoor setup that is more static, not moving compared to being outside riding, you know, through the air up a mountain on a road-going fast. You don't have as many things going on in that internal environment. And so you sometimes focus in and even more so on some of that level of what I call exercise-induced discomfort that may come along with working pretty hard.
Mac Cassin 14:50
Right? I think, basically 99 Out of every 100 people who ride a bike indoors do it because they enjoy riding a bike outdoors and they
Neal Henderson 14:59
want to be able to do it better when they go outside, or they don't have the opportunity to do it exactly because of the weather or the conditions or the time of day or whatever. And so,
Mac Cassin 15:09
yeah, that we come to the bike for the enjoyment of being outside. So being stuck inside to same with runners. And I think that the term for a treadmill is that a lot of them use the treadmill.
Neal Henderson 15:19
Yep, yep, that is a very common way of looking at it. But
Mac Cassin 15:25
so with that increased, you know, rate of perceived exertion, you know, you can either, if you're doing a time to exhaustion, maybe you can't hold the same power for as long, or maybe you're just going to put out less power for a given duration, again, just from the mental component of it, especially if you start playing in your head that you already have a bit of a decrease in power output indoors, if that starts to mess with your mind about oh, I should be able to do X amount of watts for this long, and then it kind of negatively spiral. And yeah, being mentally positive, is a massive thing. And that's probably for a lot of people, that's is an untapped area that they could focus on, too.
Neal Henderson 16:06
Yeah. And so paying attention to what you do generally can be pretty beneficial. But if you have too much attention being drawn exactly to what you're doing, like if you're focused on that power output value, and it's not right where you want to be, you're getting a lot of negative feedback at that point. And you can really, really actually, you know, be consumed from that mental perspective with all those negative thoughts and not being able to hit the target and having all that go on, is not going to help you. And so in some cases, I recommend folks kind of looking at something else or thinking about something else. Breathing is a nice one when you're riding inside during doing dirt, different efforts to think about controlling your breath, how are you breathing, as you know, or you may know, when you're stressed, you're typically doing a little bit more chest breathing, and you're just, and that's kind of that exact, you know that that rapid, shallow breathing, which isn't super effective for oxygen transfer at the lung. And so getting those deeper belly breaths where you draw that air down, you get a little bit more surface area being exposed, you have a better exchange of otoo, and co2. So being able to work on getting that kind of deeper, controlled breathing, rather than that rapid kind of exasperated, stress breathing can actually help you produce a little more power because you have a better exchange of vote to co2. That's gonna help you. Yeah, so
Mac Cassin 17:35
again, another reason why there are some benefits, there are enough benefits that outweigh the negatives for riding indoors. And again, being able to focus on these key things. No, there are not as many distractions going on as you get outside. But it is a great opportunity for you to focus on some of these other areas that won't, they're not just going to help you produce more power inside, but they're going to help improve your training, which again, it's going to help you right outside. Yep,
Neal Henderson 18:00
definitely. Well, let's move into this third area that we're thinking about, and equipment, specifically, the kind of trainer you're on is one of those things, if you go back to Episode 17, we talked about the ins and outs of indoor trainers. Definitely a lot of information, we're not going to rehash all of that right now, but for sure, different types of trainers can yield different kinds of resistance and may make it a little bit easier or more difficult to do certain types of efforts indoors on a trainer. But that being said, you have all kinds of other things that may impact that if you're on a different bike if you use as an old bike as a trainer bike, that might not be in the same position it might not have the same saddle you know, the crank length may be different, especially when you go to a different power meter. If you have a different source of power measurement, you can see, you know, some pretty drastic differences most power meters and trainers are plus or minus somewhere between one and a half and 2% accuracy. That means if you see a three or 4% difference from one power meter to another, honestly you're in the acceptable range of both of them. And 2% doesn't sound like much but if you're doing some hard efforts and let's just say you're at you know 300 watts on one but the other one is reading 309 Well geez, you know that 3% difference is something pretty real and physiologically is if there is you know, a nine-watt difference in something like that could actually be the difference between success and failure for certain intervals. And so making sure you're kind of comparing the same power measurement from one to another definitely can be quite useful in that
Mac Cassin 19:40
Yeah, especially if the power meter used indoors comes from a trainer because a lot of times you need to calibrate especially newer trainers have auto-calibration features which are really awesome in my opinion. But older trainers sometimes need to calibrate them because they do warm-up significantly and when you're talking about If they're using any type of strain gauge temperature makes a really big difference on how much strain a given amount of wattage produces. So there's, you know, you can have an instance where your trainer just is reading low or high, no one ever complains about a trainer reading high, the only hear people can train to complain about a trainer eating low, and I'm very guilty of that. But yeah, just that trainer itself can be, you mean, if you take your same power meter, a lot of people will just see different values from the trainer and their bike power meter. And that's not necessarily a bad thing. It's just
Neal Henderson 20:34
just an offset in many cases, right. And establishing and knowing what that offset is from one to another can help you adjust your targets. Because ultimately, that's kind of the important thing of having the right target that you're shooting for. In whatever setting you're in whether you're indoors or outdoors, make sure that the target that you have is set appropriately to what power meter you may have, and what that situation is, right.
Mac Cassin 21:01
And so like we were talking earlier with, you know, the difference in position and whatnot, it's important that you train for the given environment scenario, whatever that you're in. And sometimes that just means two different power meters reading differently. That's, again, it's not a bad thing. It's just if you can make those adjustments and not let it mentally get to you that I train your power trainers reading 20 Watts low, and letting that mentally defeat you out of the gate. That's, you know, there's no winning out of that. Yep, definitely.
Neal Henderson 21:31
And a lot of times, we do see like at the say, in the summer, people who've been riding outdoors almost all summer, they come inside, and they notice, man, my ability to produce power indoors is definitely less than it was outdoors, it may take you a little bit of time to kind of transition to getting used to riding the training and being able to put out a little bit more power consistently over time indoors. And then you often find when you go outside, then it's a little bit easier. Your Individual results may vary. You know, not everyone has the same experience there. But there is that bit of specificity. Either way, if you haven't been riding a trainer much at all, and you just get started well, you often see a bigger difference than somebody who has been consistently riding indoors, you have a little bit easier time hitting those targets.
Mac Cassin 22:18
And so we've been talking a lot mainly in the aspect of why your indoor power might be lower. But there are some scenarios where that isn't the case, especially if you are using the same bike or same fit indoors and outdoors. If you're used to what the trainer is all that stuff. If you have high motivation. What a trainer allows you to do is actually go so hard that you're you can go to a point where if you're riding outside, you crash, you go so deep, so hard eyes closed, clenching, whatever you put so much effort in. And there's a great photo montage of Sir Chris Hoy, who's a track sprinter. He's doing these Eric sessions and literally, he literally has a mat next to his train crash pad because he'll do efforts and go so deep that he just has to basically fall off the bike lane off leader position. If he was doing that out on the road. He you know, I'm crashing like 40 miles an hour. That's generally not the best training.
Neal Henderson 23:12
Definitely, especially as a track rider when you're clipped in on a fixed gear. That's super dangerous. I think he actually tied the kilo record riding outside. Did he not in Bolivia? Yep. And he said he wouldn't try again. Because he was afraid that he was actually going to basically go so hard that he might like blackout crash, etc.
Mac Cassin 23:32
Another fun fact about that is that his front five-spoke was on backward that probably cost him when you're point 000 the same time. Yeah, slight oversight. But yeah, that ability to just dig super deep is, you know, it's not something for everyone, but it is a benefit to indoor riding indoors and the power you can produce. You don't you do that enough times indoors, you're gonna raise your capacity outdoors.
Neal Henderson 24:00
Yeah. And you know, from a lab rotatory and like physiological perspective, you know, when we have triathletes, who you know, want to do a vo two max test are like, Well, should I do it running or should I do it on a bike running generally does have higher vo to values because your body weight is supported your upper body is moving a little bit on a bike, you don't have that. But on a treadmill going to your absolute limit where you fail has some potential risk involved unless you have a really good setup where somebody is rigged up with a harness and you can literally hoist them in the air when they fail. They have to control their they're getting off the treadmill which again puts in a little bit of fear of getting hurt. Whereas on a bike you can literally go to that absolute limit fail and all you do is coast you stop put your head down on the bars and that's about it. So you know you can go a little bit deeper in that indoors and even the other thing I think in training indoors I know in 2020 My highest one our power definitely has And indoors on a trainer because it was super consistent. I didn't have any variation, I could just set it and go. Whereas every time I did it outside, you know, say around here in Boulder going up a climb. There are some climbs that you know, are somewhat continuous for an hour. One of my favorite ones, though, is up sunshine Canyon, and there's a little downhill segment, you know, maybe halfway through or so, and getting back on it is kind of hard with that little break. And we also have the increasing elevation. And so actually the ability to produce power just because of the impact of altitude, which Man that sounds like a good episode to talk about altitude the future. Can you note that Mac put that down for a future episode?
Mac Cassin 25:40
Being noted.
Neal Henderson 25:41
But that increase in elevation means it's often more difficult to produce that power who wants to get really high, moderately high. And so you know, the indoor environment, I don't have to worry about that. That one, you know, same elevation and don't have any extra things worry about the road going downhill or a stop sign or a turn or anything. So can be nice for those some of those long efforts to just focus on doing them inside.
Yep. So well, Mac, I think, you know, we talked about those, those three different things to consider. When we're looking at our indoor and outdoor power, the physiological differences, the psychological differences in the equipment differences, paying attention to each of those and making sure that your targets are appropriate for what you're doing. It's going to help you train effectively, both inside and outside.
Mac Cassin 26:40
Yeah, I hope you've taken away that it's not necessarily a bad thing, that there's a difference in power indoors now or it's just a thing and something to be aware of.
Neal Henderson 26:50
Well, that's it for another episode of the knowledge podcast by Wahoo. Thanks for listening and we'll catch you next time.