Over/Unders are superfluous to their stated purpose

Just reading Jesse Fortson’s article ‘5 Indoor Cycling Workouts to Get Faster’. Good article. Linked below. At #1 were ‘Over/Unders’ in the classic sense…a few percent above threshold for a little while, a few percent below threshold for a little while, repeat. I’ve said in the past that these aren’t my favorite workout for the stated purpose because ramp-test derived FTP has a margin of error that exceeds the variation in work rate of these classic over/under intervals. Heck, day-to-day variation in FTP might have greater variation than a classic over/under. So you don’t know, you might just be doing a sweetspot workout instead…or you might just be exploring how the VO2max long-component affects you.

But, also, there are much easier ways to achieve the stated purpose of the workout! From the article:

“The primary objective of over-unders is to increase your ability to tolerate and utilize the metabolic byproducts that accompany riding above your FTP”

Ok. So that’s monocarboxylate transporters, primarily, right? MCT-1 and MCT-4 specifically. Anybody ever ask themselves: how long does it take to up-regulate a monocarboxylate transporter? It takes, like, an afternoon. And you don’t have to grind out big long intervals at or around threshold. Further, like so many transporters in the human body, I suspect that the gradient of up/down regulation is dictated by the gradient of concentration at the boundary. In other words, you are going to up-regulate faster if there is a LOT of lactic acid on one side of the membrane and not to much on the other side…not if you’re just a little bit above the point where you can comfortably clear the lactic acid produced.

So if you want to up-regulate MCT-4, try this novel approach: warm up for 10 minutes, then do 5 or 6 minutes at a pace where you maintain 90% or more of you resting heart rate plus 90% of the difference between your max heart rate and your resting heart rate. Then get off the bike and go about your day. 45 minutes later get on the bike and do it again. Do that 15 times. You’ll well & truly up-regulate increase your ability to tolerate and utilize the metabolic byproducts that accompany riding above your FTP by doing that.

But, doing over/unders? I don’t know. Maybe. Somebody would have to show me the biopsy. Doesn’t mean over/unders aren’t a good workout, though. They’re a good threshold type workout. And good for cultivating mental toughness.


That’s 90 mins over the day just above my LTHR. Does that sound about right?

3hr 45min on the bike, with 15 times on/off the bike, spread out over 15 hours?

Haha, no thanks!

Also this reminds me of doing ‘10 push ups every hour for 8 hours’, which is fine and all but less effective than doing 80 pushups in fewer, larger sets. (not that pushups are the same as cycling training)

It seems like you could get the same benefit with much less time by staying on the bike and extending the work intervals. I feel like at least half of the 5 minute work intervals wouldn’t even be productive training stress as the body warms up to the work.

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Sorry to be pedantic


Another reason from a world tour physiologist and professor that has studied lactate and athletes for almost 20 years:

That approach worked for me, even on time limited 6-8 hours/week.



Thanks for doing that math for me…

But yea, I can sneak in some pushups or squats or something every hour on the hour during my workday and during parental chauffeur duties, but I can’t commit to 15 minutes of every hour on the bike. That’s some goofy life-logic right there.

If it works for you great, but you must have a different day to go about than me. Who really spends 15 hours within arms reach of their bike, and who can commit to 15 minutes of every hour, for 15 hours during a day to riding?

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Ha! Yeah. Well, my understanding of the Cori cycle is that pyruvate meets LDH and you wind up with lactic acid in the sarcoplasm. Of course, a proton dissociates in solution and lactate is transported through the membrane…which is what is found in the blood: lactate. But, for sure, the end result of lactic acid fermentation is lactic acid.

Well, I disagree with this but the end result can be the same: lower blood lactate at a given workrate. It’s not due to improved lactate clearance, though. (at least not if the adaptation stimulus is Z2 work). It’s due to less lactate production. In other words, the athlete has the ability to generate more energy in the Krebs cycle…not as much pyruvate piles up…no need to increase Cori cycle activity…less lactate crosses the membrane…less blood lactate.

I don’t think Z2 work stimulates monocarboxylate transport up-regulation.

And, most certainly, it DID work for you. So there is that!

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It is pretty good to be me!

But this protocol was not developed by me. I’ve just seen the biopsy results, is all. I will say that I have ‘lifted all day’ many times in the past. We used to have watch parties for fights or foot ball games…every round we’d run out to the garage and snatch…or do some cleans…something. Fun times.

Also, again, if the goal is to improve your ability to clear lactate, it might be better to dedicate 12 hours to an EFFECTIVE protocol than spend hours doing over/unders…which don’t help much…over the course of many weeks. But these are decisions we all must make. You may also rationalize it…you know, convince yourself that it doesn’t matter if over/unders don’t do a lot to improve lactate transport but you just like to do over/unders. That’s fine too. It’s not like our lives depend on getting things correct.

This stuff still makes my head spin, maybe I don’t understand lactate clearance. I thought it was primarily about shuttling lactate out of the blood and into the liver, kidney, heart, etc.

Regardless, San Millan and other coaches/physiologists seem to put more emphasis on zone2 work along with some work above threshold. Over/unders? My coach rarely assigns them. Just a metric ton of z2/z3 and some above threshold work, and it has sent my FTP higher than more threshold approaches (TR) and I’m much stronger above threshold.

Do you know of any studies showing decreased lactate accumulation (and hence a higher FTP) by a short up-regulating MCT-4 intervention? Even if it is your own study of n=1.

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There are a few. Definitely even one cycling workout at 60% vo2peak for several hours results in increases in both MCT1 and MCT4 after a few days of recovery. But not by +30% like the protocol I mentioned. Either way, that’s just getting lactate out of the muscle cell. All other things equal that would mean higher blood concetration. :crazy_face:

But to me the bottom line in your workout plan…you sort of solved the puzzle for yourself. I mean, I’m not sure there’s anything for you to figure out, here! MCT up-regulation probably has an upper boundary.

But for those who feel like they need better clearance of lactate from the muscle over/unders may not be accomplishing that task as well as some other methods can. The advantage of z2 work in this respect is that you can do a ton of it w/o overtraining…but it only improves MCT1/MCT4 a little bit after several days. The advantage of repeated 5 minute intervals is that you get a WHOPPING up-regulation after a day of training 90 minutes cumulative VO2max work. And you get some pretty impressive gains in glucose transport, as well.

I’d like to see that data repeated for really well trained cyclists, though. Not just a bunch of schlubs like me with a 5-handle VO2max.

I guess another way to ask the question - is MCT-1/MCT-4 the limiter or is it something else?

You’ve got San Millan and in his work with amateurs and pros, his conclusion is that zone2 is the primary driver of adaptations to improve lactate threshold. His other point is that the other driver is work above threshold.

Z2 reduces lactate production; threshold stuff promotes lactate shutling…or have I got that wrong? : :woozy_face:

My head hurts 😵‍💫

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I did a 6 hour gravel race earlier this year where I was around that heart rate for ~90 minutes total spread throughout the race, is that the same effect as your protocol? What about spreading it over 2-3 days? Same end effect or does the overnight recovery lessen it?

Should I wear the same chamois the whole day, or have 15 different pairs?


I’ve kept all my old bibs for a protocol like this!

I only care about performance, not the underlying mechanism. That said, as I understand it, the explanation starts with having more mitochondria to clear it within the muscle, before pyruvate has a chance to become lactate in the blood stream. And that is a complex process and a couple of key players are mitochondria rich slow twitch muscle fibers + MCT-1, along with the pyruvate generators your fast twitch muscle fibers + MCT-4. Head is hurting again :dizzy_face:

Bottom line - if dancing the conga line will make me faster, I’ll do it (within reason). One thing I know is that @Brennus finds interesting foundational studies and then tries them. So I’ll read and consider anything he posts.


This article explains it far better than I ever could. https://trainingpeaks.com/blog/zone-2-training-for-endurance-athletes/


Dude, you are home way more than me. I am up and off to work within 30 minutes of wake up at 6am. Get home about 9-930pm. Ride for an hour or whatever and then straight to bed and do it again. How can you get close to your bike that many times a day? I’m only home less than nine hours a day. Rest is working.

High five. Way to work hard. If that’s your schedule, that’s your schedule. Gotta deal with what you have.

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