Training Adaptations - Blog Posts

FTP Increases vs Progression Level Decreases | Training Journal #4

I tabbed a big red button and now somewhat regret it.

After my Monday rest day, I completed a sweetspot and an endurance workout. Nothing special during those.

Then, after I finished last night's endurance ride, Trainerroad (TR) told me that an AI FTP detection was available. I briefly considered postponing it until the end of this week which happens to be my last "proper" week of base 1 (by proper I mean "not recovery" which of course is important as well). But then, you know, these red buttons are enticing. And so I tabbed.

The AI told me that my FTP had increased by 6 watts. Nothing spectacular. But in the TR world, FTP increases come at an opportunity cost: your progression levels (PLs) will go down. If you aren't aware of what PLs on TR are, you can read this blog post. The tl;dr is that PLs assess your capabilities in specific zones based on the workouts you completed and your responses to them. PLs are then used to pick adequate workouts for you in those zones.

Instead of only relying on your FTP number, this means workout selection can be more fine-tuned. PLs will, for example, influence the length of the intervals at a given intensity and the rest periods between them (indirectly, by picking workouts of certain TR-internal scores). And that's exactly where said opportunity cost comes in.

Once I accepted the FTP change - which I once again did have to confirm, so no one to blame but myself - my PLs dropped rather significantly. While I don't know the algorithm TR uses, a Threshold drop from 5 to 3.4 seems significant, especially given the rather small increase in FTP watts.

Those PL drops, then, resulted in a change of my next workouts. I had finally trained up to the point that my upcoming sweetspot workout would have included 15-minute intervals. The workout it was replaced with only has (more) 4-minute intervals.

Why is that bugging me a bit, you wonder?

Well, the below episode of the rather brilliant Empirical Cycling podcast explains why there is a minimum duration that your FTP/Threshold intervals should have in order to effectively stress the targeted energy system and trigger the intended adaptations - around 15 minutes, according to Kolie Moore.

I assume that the same logic applies to other zones/energy systems too. Moreover, the lower the zone/intensity, the longer the minimum time should be. So in the case of sweetspot intervals, 15 minutes is really the bottom end of effective SS work.

Now, don't get me wrong, it's certainly a good choice by TR to ramp people up to higher interval durations. Progressive overload, target audience, and so forth. And the PL system makes a lot of sense to me as well. It's just that I would have certainly preferred to finish my training block with longer intervals, even at slightly lower watts. And I have the hunch that it would have been the better choice in terms of physiological adaptations as well.

As said, Trainerroad gave me the choice and I did have some doubts about going ahead. So I should have postponed the AI FTP detection by a few days. But then, from a system design aspect, it would maybe make more sense, in a situation like mine, to postpone the prominent call-to-action ("new AI FTP detection available") until the recovery week. After all, it's hard to resist the curiosity and potential gratification that might come with a higher FTP.