How well does %FTP work for you?

This workout will help you see whether your %FTP based intervals are well suited. If your MPA is higher on the second %FTP-based set, %FTP workouts will be too easy. If your MPA is lower on the second %FTP-based set, they will be harder.

If you have a signature of 1000W/20kj/250W both sets will be the same. The percentages are based on this “average” signature.


I’m not sure what to make from this (I’m still learning the intricacies of Xert)
Should we be striving to have both sets be equal?
I opened the workout and it had my MPA lower on the second %FTP based set, so my workouts will be harder.
I want to improve so I expect (wrongly?) that my workouts would be harder.
I also know I’m well below the average signature.
If you could expand on what this means and how I (we) should react to it would be much appreciated.

Hey Albert,

This isn’t a way to evaluate your fitness but is a way to understand what happens when you follow a workout from any system that uses %FTP as the target for the intervals. A generically defined workout that uses %FTP, needs to base the targets on some average athlete. What this shows is that if you’re the average athlete, both first and second interval sets would have the same MPA profile. However, if your signature is a bit different (perhaps you’re more of a sprinter with larger PP and HIE vs. TP or an diesel engine with a big TP and smaller PP and HIE) then the second interval set will be different for you.

Using %FTP as interval targets are well-suited if this workout has 2 equal profiles. If not, you might be training too easy (MPA is higher in the second) or too hard (MPA is lower in the second) than what you should be doing for effective training.

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Thank you
I’m slowly getting theree

So %FTP-based intervals would be too easy for me?

The difference seems pretty significant. Is it? What does it say about my profile?


Just to clarify, I assume you are referring to intervals above threshold, rather than all intervals, when you say they would it find it easier / harder? And the opposite would be true for %FTP intervals below threshold…? Someone with a high HIE would find it relatively easier to hold say 120% FTP for 5 minutes vs someone with low HIE, but presumably much harder to do 30 minute intervals at 90% FTP (as it’s relatively further above LTP / generates more XSSR / difficulty)

That’s a good catch @wescaine Yes. This test applies to intervals above TP. Indeed, intervals below TP are the opposite. However, as an assessment of how well %FTP works, the test is effective in highlighting the issues both above and below FTP. If MPA rises in the second set, above FTP intervals are too easy and below FTP too hard. Vice versa if MPA declines.

If you’re using Xert, and you’re doing intervals based on %FTP rather than MMP aren’t you doing it wrong?

Also if you’re not using Xert. :slight_smile:

I think for workouts below treshold, a comparable test would also be relevant (although I cannot think of how to construct it). I noticed that when I am fit, not only my FTP increases, but Sweet Spot-workouts also become easier. Last year, I really feared the 3x20 Minute @90% Sweetspot (by the way - it appears to me that you have removed it? Why) now it is easy as is the 4x16 Seiler. This coincides with my LTP having risen significantly. My theory: people with a high LTP can ride closer to FTP for longer and have less perceived exertion close to FTP.

For riding above FTP as is the scope of the workout discussed here, I am not sure the MPA-story is the whole truth. People that have a low VO2Max and a comparably high FTP are not necessarily (but can be) limited by their HIE (which I think represents the buffering capacity). They can also be limited by their VO2Max. For me, I notice a difference above FTP as there are two reasons for which I possibly might fail. Legs and Air. Failing legs in my opinion represents HIE depletion as I read that HIE reflects dFRC. DFRC again - afaik - represents the buffering capacity (ability to buffer excess lactate that cannot be metabolized). But what about “air”? Many workouts I cannot complete because I run out of air; my legs are fine (well, not fine, but they could do longer). I also cannot empty my HIE in one huge gulp of suffering. I gradually have to bring it down with rests in between as otherwise, I suffocate. So when I look at VO2Max workouts that aim at 40% MPA - unsustainable for me. I can impossibly get to 40% MPA in one pull; at least not in an 6-8 minute pull. I can “cheat” by sprinting because the delay of the “cardiac punishment” buys me 15-20 seconds.

Search for “sweet” rather than sweetspot or sweet-spot.:wink:
I too used to avoid SS (last year) but haven’t found them too challenging this year.
Not sure why, but I’ll blame it on Xert. :laughing:
I did carry 3 stars status into winter this year so no doubt that is a factor.
I dialed IR down to reduce hours when starting Base, but I already feel stronger this year with over a month to go (TED arbitrarily set to Aprill 11).

Nah, the workout is gone. Cannot even find it when sorting according to duration and then go to the “1:36:00” section.

Search for “takes two”.

Brings up 2x20@90%. There also was a 3x20@90%, duration 1:36:00. “Takes three” neither did the trick ;).

Perhaps someone made one and had shared it?
I suppose you could make the argument it wasn’t “Classic”. :slight_smile:

Hmm do shared workouts appear under “Standard” in the workout section? Do not think so.

Easiest way to add it would be to open the 3x20@82%, Copy, change to 90%, and save as 3x20@90%. Then it’s in your Personal folder.
However, I think we have gone OT. :slight_smile: I believe the gist of which is why use %FTP when there are better ways to train using SMART intervals that scale to your signature.
Doesn’t the traditional 75, 82, 90+ method fall apart at some level?
I’d much rather ride variable intervals that pass through or wander about in aqua/green when I have a choice. That is what you end up doing outdoors if you want to focus on that zone.

An untrained HIE will have you struggling to handle the discomfort of high intensity intervals. Remember as your training loads go up, it both raises signature numbers and improves your capacity to express them.

Your Low Training Load might be well developed but if your High Training Load isn’t, you will struggle with all intensities above TP. Cheeky efforts to sneak past MPA with a short burst might be ok for a second or two but won’t often yield a breakthrough with the best results.

Type “Sweet” in the search bar on the Standard Workout Library page and you should see all workouts that are related.

If you haven’t read our blog on Sweet-spot and keen to understand how things work in Xert (and elsehwere), read it here. Made a copy of 82% as suggested and increased to 90%.