Training the wrong energy system?

My rider type is Attacker, and while my AC appears to be decent, my MAP needs work. So I use a MAP training block to raise it. But after a Full Frontal, I am consistently unable to complete the VO2Max intervals.
Typically, I can hold the prescribed power for a maximum of 1:30 to 2 minutes. As recommended, I then end the interval, and start the next one after a longer recovery and the prescribed target power.
Basically, I’m doing 1:30 to 2:00 intervals (max) regardless of what the workout says, since I can’t hold the power any longer.

Will this type of training do anything for my VO2Max or am I just training my AC?


I would not go so far as to say you are not hitting your MAP by doing 1:30 - 2 Mins … Not all the MAP workouts are 4mins Intervals (eg. Butter is 90 Seconds).

Which workouts are you typically struggling with? If 9Hammers or A Very Dark Place, you will find many posts here of people failing … so do not despair!

A few things to try as recommended by Sufferfest. Try to maintain the target power of the effort as long as possible. If your power begins to dip, end the effort and begin your recovery. Still unable to hold the target power through the end of the effort? Pause the workout and double the recommended recovery time.

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It’s true that when you do “traditional” vo2max intervals, you’re also making use of anaerobic energy production pathways and so i guess you could say training that ‘system’ for lack of a better word. It’s not a bad thing, it’s just there’s no way around it because the power’s so high.

Whether it also is training your Vo2max i think probably a bit depends. There are probably a bunch of different ways to approach this because, well, as you know, the SUF breakdown of NM, AC, MAP and FTP is a simplified model, in reality all these metabolic processes are happening on top of each other and everything kinda overlaps.

So questions, (i) as @Joe asked, what workouts are you doing? (ii) What power are you trying to hit in these intervals in comparison to the MAP value from your full frontal, and (ii) are you starting to fail intervals right from the very outset at the beginning of the workout or does it only happen once you get towards the end?

I ask about FF MAP vs. these intervals because often these vo2max interval workouts give you power targets that are lower than your MAP value from FF. Like I’m looking at the first interval of AVDP and the target is 30 watts below my MAP from FF. So still hard, but if i’m not able to hold it for 5 minutes or longer, it maybe means something is wrong. Like rest, nutrition, recovery wise. Vo2max workouts are demanding and you really do need to put yourself in a position where you can dig deep. Go into it fueled, and relatively rested.

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Thanks for your suggestions and answers, @Joe and @devolikewhoa ! Workouts I recently did and could not complete: There Is No Try, Joy Ride, 14 Vise Grips, Nine Hammers (ok, that one is no surprise).
I used to be able to complete e.g. 14 Vise Grips before doing the FF (coming from a 12 week general road cycling plan).
It’s only the longer intervals I’m failing.

Which workouts I’m doing doesn’t matter that much, generally speaking if it’s yellow and longer than 2 minutes, I’m not able to complete it.

The target power typically is right at or around my MAP result from FF (318). For comparison, my AC is 479. So, it is significantly lower.

What makes me suspicious is that going for 1:30 or 2 minutes is quite “near” the target duration for AC efforts, and I’m not fading away (like what is common during more “FTP-style” intervals), but really failing from one moment to the other. It doesn’t really matter when during the overall workout the interval happens (I do recover very well).

So, to me, it looks a bit like my AC system is doing most of the work at the beginning of the interval, and since it’s not pushed to its limit, it can hold on a bit longer, but once the aerobic system needs to take over, it just fails for whatever reason.

It’s an oversimplification for sure, but VO2Max is my weak spot (always has been) and I really need to train it, and not doing half-hearted AC intervals … :wink:

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I wouldn’t discount the MAP workout you’re still getting by only doing <2min intervals.

E.g. A session like Revolver with all intervals at 1min has more focus on developing MAP than AC (according to the app overview!). Sure, the first few repeats will be leaning on your AC but by the end of the session it’ll all be about MAP since the recovery is short.


You can also try these workouts in LVL mode.
When you start to struggle, just lower your cadence or/and a cog.

I believe this will boost your confidence, because you will still “complete” the interval.
And hopefully, after some time your body will get used to the duration.


Have you tried any of the MAP workouts in Level mode instead of erg? I’d recommend that, as instead of grinding to a halt when you can no longer sustain the power, you can still finish the interval to the best of your ability, even if you fade some. This will ensure that your aerobic system can work and. contribute in the final stages when you would normally quit the interval early.
Give it a shot for a few weeks and see if you notice any improvement!


I think you are right that anaerobic pathways supply the energy that makes your power in the beginning of the interval. But even during that 1 to 2 mins aerobic energy production is ramping up. My (admittedly VERY dilettantish) understanding of how intense intervals increase vo2max is that it’s not necessarily that your aerobic system “takes over” and then you train it but rather that you need to hit your max flux rate of oxygen (max oxygen uptake), and this then creates the signals that drive the central adaptations to improve, and in order to get there, you usually need to be working longer than the AC alone can support, OR with little rest (more on that in a second).

So for the longer intervals, i second what everyone says about trying it on LVL mode. Because if you start out at 318 and then at minute two are dropping to 310 and then 305, you’re still going to be getting those adaptations if the power–even though it dropped–is still high enough to get you to vo2max. And if you see heart rate and breathing still climbing, it probably is. Doing it in erg mode makes the whole thing very binary (pass/fail) whereas in reality there’s a range of power outputs that can achieve what you want.

OR as people also said, you could start out with something like revolver. This gets you up to Vo2max more gradually because the intervals are shorter but the rests are shorter also. In the beginning it probably will feel easy because of your strong AC but by a few intervals in, should feel hard, with HR and breathing way up.


Thanks for all your suggestions and ideas! I will try reducing the power throughout the interval and focus on finishing. With Nine Hammers scheduled for tomorrow, I have a prime candidate for that strategy.

Also, I notice that I seem to be the only one still on a dumb turbo trainer and a crank-based power meter - all my workouts are in Level mode :wink:

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Would it be better to do MAP intervals at a power level you can sustain for the whole interval rather than starting high and fading during the interval? For example next time I attempt 9 Hammers I’m thinking of setting MAP at 90% because 100% is unrealistic for me to hold beyond the 4th Hammer.

I do like the idea of using Level mode too, but again was thinking of targeting what I think I could realistically hold for the interval rather than starting off at 100% and then fading. Maybe start off at 90% and try to hold it throughout or even finish higher if possible.

Whenever I do FF I always aim to hold a constant power over the 5 min MAP interval rather than starting higher and fading toward the end.

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I was going to suggest this. I struggle with longer MAP intervals, but find that level mode is much better and I end up surprisingly close to target, when I would have completely failed it in ERG mode.

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While it may seem like it, I know you’re not the ONLY one not using a smart trainer. I myself didn’t switch to a Kickr until I began working for Wahoo just over a year ago. I think there are benefits to both.

Yes, I think this strategy definitely has merit. I’ve had coaches in the past whose workout strategy was to always finish stronger than you started. And actually, Sir Neal usually advocates for finishing a workout knowing that you can still do a little more, rather than completely smashing yourself on every workout. *Certain workouts don’t really fit this strategy, it’s a 95% rule :wink:


I started on a dumb trainer using virtual watts last year in March and didn’t get my Smart Trainer until October which was a fluke gift. I had planned to stay on a dumb trainer and get power pedals. Anyway…

I find that if you’re having trouble holding the targets in ERG mode, but still have life in your legs, a switch to Level mode really helps. Then I can hold somewhere --close-- to the power target and not hit the death spiral and get a much better workout than if I kept grinding away at a low cadence - or fail altogether and grind to a stop in erg mode.

Today I did Extra Shot in Level Mode. I didn’t have to turn down the intensity. And I was able to get close to the targets when I was able, and then hold power --close–to the targets when I wasn’t. And then I could keep the cadence I wanted instead of grinding into a death spiral and lowering my workout intensity in erg mode.


I’m curious about this too! My weakness is almost always MAP- funny thing is sometimes after FF it rates me as a Time Trialist and other times as an Attacker… never all-arounder and never whatever-you-get-when-you-are-good-at-MAP!

I also have a dumb trainer with speed sensor, selectable by Sufferfest. It works fine.

I like the idea of trying level mode and/or tweaking the targets just a bit on your 3-5 minute efforts to ensure completion. Maybe tweak the targets back up for the last 1 or 2 repeats? I’d defer to a coach on it but that does sound good. You are probably missing out on some metabolic stimulus if you never do repeats in the 3-5 min range.