Does this prove over/unders don't work any better than riding at tempo?

TLDR warning.

This is taken from the POL for lower volume cyclists thread & I thought it would be interesting to create a stand alone thread. @GoLongThenGoHome linked a paper that included a reference to this paper comparing polarized vs non-polarized training for cyclists.

In that paper cyclists trained using an 80/0/20 (Z1/Z2/Z3 where Z1 is <1st lactate turn point and Z3 is >2nd lactate turn point) or a 55/45/0 training distribution. So the non-polarized training regimen included NO WORK at or above threshold. The polarized training Z3 work was modeled after the Stepto-Hawley ‘best case’ training from their papers…this workout has been in my custom workouts list for a few years now. It’s basically 4 minutes at ~110% FTP (85% PPO), 90 seconds rest, 8 times…but in this paper they just did 6x 4min @ 85% PPO followed by 2min rest. So not exactly the Stepto-Hawley protocol as they imply but very similar.

The interesting thing wrt to Over/Unders, Hunter took monocarboxylase transporter 1 & 4 pre/post intervention. MCT1 transport lactate from the blood across a cell membrane. MCT4 transports lactate from ‘inside the cell’ to the blood. MCT4 up-regulated dramatically in both groups but THERE WAS NO STATISTICAL DIFFERENCE between polarized and non-polarized training.


If you look at a classic TR Over-Under workout (Emerson) you will see that the purpose of the workout is to ‘effectively train your muscles to process the lactic buildup while still going pretty hard.’ Working a little above FTP ‘flood the muscle with metabolic byproducts’ and then working a little below FTP allows those ‘metabolic byproducts’ to clear.

Sounds like a good theory but the riders in this study were able to up-regulate Lactate-to-bloodstream transport substantially without ever riding at or above threshold. Very, very interesting…and maybe a little humorous that so many riders have slogged through hated over/under workouts that could have been done just as well with a tempo workout.


Is that not much of the point of the ISM training philosophy ?
Increase your ability to deal with lactate via low intensity?

But as for o/u’s themselves, they’re also surely just great IRL specific “suffering practice”?


Ism is about burning fat not dealing with lactic acid

It’s not just about that no. It’s about producing efficient mitochondria within the slow twitch fibres that yes burn fat and help you spare glycogen but also produce lots of MCT transporters so your slow twitch muscles can use the lactate produced by your fast twitch muscle fibres as a fuel.

From FastTalk episode 165

Trevor Connor 18:58
What would you suggest for building that lactate clearance? Is it something that you work on in the base season? Or is this in season training thing?
Dr. Inigo San Millan 19:07
So, I think that the main time to do this is in the offseason, at least this is what I do with my athletes. I do that in the offseason, and this is what I call the zone two, but 25 years ago people would laugh at these concepts and now people are talking about zone two. But yeah, I think that this is very important because this is the exercise intensity where you are stimulating those muscle fibers type ones in the mitochondria to both clear lactate as well as to burn fat, and as we discussed, this is something that it doesn’t take, you know, couple of weeks or so it takes at least two months. So, this is what the best time you have to build this is in the offseason, once you start the season, you don’t have much time to do this, you need, as we discussed, to focus on high-intensity exercise and recovery, but you should at least keep simulating here and there that zone two because you will deteriorate. And this is what I see, and I’ve seen over the years, not just enough in cyclists, but in other athletes, that when they stop completely doing zone two, halfway through the season, or towards the end of the season, you see a decrease in fat burning capacity, as well as in lactate clearance capacity, because all they have done has been racing and recovery, but they haven’t been able to do this translated into the world of professional cycling at the highest level, this is one of the reasons why, you know, more and more athletes pace their competition quite a bit, and even take time off in the middle of the competition to rebuild the base, or to keep stimulating to take a break from competition and in recovery, and put together good solid blocks of training where they revisit zone two, that is that capacity for mitochondrial function, and then also high intensity. But that’s what I’ve seen over the years, both in the real world, as well as in the laboratory looking at fat oxidation and lactate capacity, that’s what it takes.


Interesting side note is Trevor’s reference here to an athlete with what you might call TR/Zwift Racing/Sufferfest/Group ride smash fest/HIIT type fitness.
What he’s describing is someone with tons of MCT4 expression but little in the way of MCT1 to actually make use of it.

Physiology of High-Intensity Work
Trevor Connor 15:08
I’ve talked about this on the show before, but one of the best examples I’ve ever seen of what happens when somebody does a ton of high intensity is there was this master’s athlete that I started working with, he was all intensity all the time, and when I started working with him, he was like, “Oh, let me send you this test result that I did.” It was a bit of an odd test where the examiner just had him ride for an hour at about 240-250 watts, which was below his threshold. So, would have been kind of that between VT1 and VT2 type effort for him, and the entire hour he was maintaining his lactates at like, seven or eight millimoles. Which you just look at and go, how are you sustaining that? And I talked to the guy who gave the test he’s like, “Oh, yeah, I see this master’s somewhat frequently. It’s because it’s not that they’re producing tons of lactate, it’s that they haven’t developed that system.” So, the muscle fibers are pumping the lactate out into the blood, but there are no slow-twitch fibers really taking it back up. So, it just sits there in the blood and accumulates.
Dr. Inigo San Millan 16:23
Yeah, exactly. This is why doing lactate testing is a very good surrogate to know what happens at the mitochondrial level, right? If you have solid mitochondria, and you are able to clear lactate coming from the fast-twitch muscle fibers exported by those transporters that I mentioned earlier, the MCT4, and they’re imported into these slow-twitch muscle fibers into the mitochondria by another transporter, which is MCT1, and they’re metabolized there for fuel. So, you’re not only getting rid of that escape microenvironment, but you’ll see you use lactate as extra fuel, and lactase is a more potent fuel than carbohydrates


Not based on the TR text description accompanying each workout. :crazy_face:

“Emerson’s primary objective is to increase your ability to tolerate and utilize the byproducts that accompany riding above your FTP, all while maintaining a reasonably high power output.”

Which is still true! But if we were to take a survey, ‘What TR workouts are hardest?’ I bet over/under workouts would make the list. Probably at least top 5.

So for all those athletes that hate over/under workouts, I HAVE GOOD NEWS: don’t do them. You can achieve similar adaptation by doing tempo or sweet spot or even just riding a little above your ventilatory threshold.

How quickly do MCT 1 and 4 changes occur (up or down) in response to training or detraining?

It’d be interesting to know whether those adaptations would change over time. Nothing there was an increase in LTP, does that mean the same number of transporters are better at their job, or is that completely independent?

But that’s just marketing surely. Even at my biggest TR fanboi peak I never believed any of that gumph :rofl::rofl:

It’s the same as all the deep-dives and stuff on the podcast: it’s just an illusion to create an image of complexity by association.

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Caveat: over/unders are GREAT preparation for rides/races where you are riding with people who are faster/stronger than you.

For me that’s a reason to do them as well as steady-state intervals.


It’s actually about fat oxidation which occurs in the same aerobic zone as lactate recycling. So as far as I can tell part of the training adaptation is pushing that fat oxidation zone to a higher wattage which has a dual effect of allowing lactate recycling at higher wattages.

For me, regardless of deep diving into the science, I agree with @Helvellyn - there is a lot to be said for actually being able to mentally cope with the feeling being over threshold. You need to know what it feels like and you need to have confidence you can survive over threshold in a race situation or when a steep climb comes up etc.


He preaches metabolic flexibility, but in my experience doing middle zone moves the needle of improving lactate metabolism much better than z2.

This is from lactate measurements. Z2 work does not lower my lactate at a specific percentage of threshold power, but moves the whole curve to the right.

Very commendable, then. You are wise beyond your years!

But shame on you for knowing and never saying so during the many over/under conversations we’ve had on this forum. :rofl: So many have suffered needlessly because you held your tongue.


But shouldn’t the question be: Do this improve your performance? So you have proven data that you can upregulate MCT 1 & 4. But does it actually do anything to improve performance? Do you take your lab results to the race director and say, look, I have more MCT transporters so I win. It’s a cool research paper and looks good on paper, but paper doesn’t win bike races. I’m being slightly facetious here, but it would seem that the end goal of winning a race or setting new KOMs or whatever should be the factor when determining what is best.

Hypothetical, but let’s say you just do Z2 and/or tempo and you upregulate MCT. Other person does over/unders and doesn’t have the same MCT boost, but they increase their FTP, or increase their repeatability, or increase their 5 and 10 minute power. What training is deemed better then?


Well I think you’re just making another argument that over/unders are a waste of time. :smiley:

Mostly I just think it’s funny that so many people hate doing over/unders and the whole time they were slogging them out the intended adaptation they were getting was not much better than riding tempo. C’mon…that’s a little bit funny, right?

As to what is really going on…I’ve always believed that up or down regulation of transporters in any membrane of any critter depends on the relative difference in concentration of the substance being transported on either side of the membrane. If the difference is large there will be material UP regulation.

So if you want MCT4 to up-regulate you need a high concentration of lactate in the sarcoplasm. If you want to up-regulate MCT1 you need a high concentration of lactate in the blood relative to the sarcoplasm. That’s why no up-regulation of MCT1 was observed in this experiement…sarcoplasm already had a high lactate concentration so transport of lactate from the blood to the muscle cell was unlikely to occur (what about up/down regulation of tissues in the body outside the muscle? That’s an interesting though).

So for my money the best way to up-regulate the lactate shuttle is the way that generates the most lactate. I know from futzing around with my own lactate response that the best way is hard start intervals sustained at or around threshold. Next best option would be floats. But this data causes me to question even that.

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If they get better results I’m failing to see how they’re a waste of time. I’m saying you’re focusing on the MCT transporters as an indicator of results. And I’m saying that who cares what happens to MCTs? Results are the results.

Maybe they don’t upregulate MCTs. Who cares. Again, I think performance should be the test. If you think that tempo is going to give you better performance, cool. But if over/unders are getting you FTP gains, or better mental fortitude, or the ability to keep a break away off the front, I’ll take that. At the end of the day, I couldn’t care less what is happening to whatever transporters or proteins if it isn’t making me faster. If it’s proven that an increase in MCTs correlates to better performance then I’m in. If it’s just showing a higher number for one training modality, does it really even matter?

I think they touched upon it in the podcast a few times, but basically they’ve said that it’s fine and dandy to pick out mechanisms and proteins and study them individually. But one, the human body isn’t that simple. Things don’t happen in a vacuum, meaning that looking at a single transporter isn’t the whole picture. But their big take away for me was that performance should be the ultimate determination. Is it making you faster? That’s it.

Not me. I just copied and pasted text from over/under workouts.

The main point is this: the stated primary goal of TR over/under workouts is to “increase your ability to tolerate and utilize the byproducts that accompany riding above your FTP” I didn’t say that. TR said that.

I just think it’s funny that so many people hate doing over/under workouts but they slog through them…but this data indicate tempo work is pretty much as effective at achieving the intended adaptation.

If you want to know what I specifically think about how to adapt and improve your lactate shuttle…first of all, I’m flattered by your interest! & second of all, please review my previous post.

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That’s not performance, surely you are referring to actual results rather than just another number?

If you’re following a plan just shut up and follow it :rofl:
You’ll be telling me you didn’t do Chad’s single legs drills next :yawning_face: :rofl::rofl:


Yea, I’ll give you that. The workout text for over/unders says lactate shuttling is the goal. But it also says “tolerate…riding above FTP,” which can’t be overlooked and doesn’t happen at tempo. And again, who knows if those 2 MCTs are the only factor in lactate shuttling. We can’t look at single mechanisms in a vacuum.

The intended adaptation is better utilization of lactate. The data shows that tempo may be as good at upregulating MCTs. Those may not be the same thing. They could be, but looking at a single mechanism or a single pathway may be missing the whole picture. That’s all I’m saying. Performance is what matters.

That’s why I said race wins or KOMs or whatever your goal is. If your goal is to have a lot of MCTs, cool. I’d rather win.