No disagreement from me on this point. My question is why it seems that workouts at or below FTP (so Threshold/SS) do bump progression levels for lower zones, while those above (VO2, anaerobic) don’t.
I see that now, that is an interesting observation. I’m guessing its because its harder to extrapolate how well you could do on longer sweet spot or threshold intervals based on your performance in shorter VO2 max intervals. I think the true threshold PL for the workout you shared Birks is definitely a lot higher than 1.1 but TR doesn’t want to risk overestimating it and is assuming you are going to be doing threshold workouts as well
I’ve been doing a TR plan. The only thing I changed was using alternates available to me and letting it do the adaptations.
I don’t see the issue? The second ride fits in the 56-75% window. The first is just below, but then again, it was 5 h, so…
Are you doing a specialty plan like the criterium specialty? If you are in base or build your endurance PLs should be ramping up similarly to your others. If you are in criterium specialty that could explain why you keep getting harder VO2 workouts and not harder endurance workouts.
I used the plan builder. Was that not the right thing to do?
Plan builder is great, and if you are in specialty phase right now getting ready for an event there is nothing wrong with that. I was just trying to make sense of how your VO2 progression level got so high relative to everything else. If you want more focus on endurance, sweet spot, and threshold I would suggest doing a base block next. Since you used plan builder you should be able to see on the calendar what block you have coming up next
I’m not in a specialty phase. It did force me to choose a discipline, even when I said I wasn’t training for anything, so I picked rolling road race. The only thing I set it for was a 2 month expiration, as I’m going on vacation at the end of Jan and wanted it to wrap up before I was off for a whole week.
@The_Cog so, my takeaway here is that a 1 or 1.5 hour indoor “endurance” ride with an IF of, say, .6 to .65 isn’t good enough if training stimulus (as opposed to a recovery ride, or just spinning the pedals for the sake of it) is the goal of that session. Is that correct?
An interesting thread.
I haven’t spent any time looking at the IF or % of my ftp that I do my z2 rides at. Mostly I just go on what I consider to be m z2 hr, and work out backwards from there. Of course this has a tendency to shift depending on the duration of the ride, where there is some drift upward as duration increases.
This seems to correlate pretty well with the idea of a flat % of ftp zone and an IF based upon duration being fundamentally different things, which I hadn’t considered. I love the idea of the fluctuation of outdoor or unstructured riding having an impact on IF and that being a better description of the effort. Very cool.
Generally my z2 / 3 crossover is somewhere in the mid .70s, especially if you go off what I consider a more accurate FTP than the TR AI version. Given that gap TRs highest IFs are actually lower by value than I’d expect but in pure watts pretty accurate for the z2 % I am comfortable riding at.
I’ve just come back to TR and what I’m hoping to do is simply push the endurance alternates until I get closer to a z2/z3 crossover hr that matches my expectation, both for durations I want to ride at, and intensities that make sense for those durations.
I think a lot of the struggle is getting into the slipstream of the TR model as it were. I’m hoping some early hand holding (and occasional corrections) will lead to a smoother experience in a few blocks.
Here’s hoping for the best in 2024. 
Correct, it’s too easy, at least for anything less than probably a 5+ h ride.
For anyone who wants to dispute that statement: let’s toss out measurement of power, the notion of FTP, etc., and just think of it in traditional terms, i.e., relative to VO2max.
In that realm, anything less than about 55% of VO2max would be considered low intensity exercise, too low to induce significant physiological adaptations, at least/especially in an individual who is already endurance trained. Relatedly, Seiler places his “lower pole” around 60% of VO2max. Yet, on average an IF of 0.60-0.65 corresponds to only 48-52% of VO2max, because the average trained cyclist has an FTP of about 80% of VO2max.
If somebody suffers from cumulative fatigue from doing their “moderate intensity filler workouts” at an IF of 0.75-0.85, odds are that they have either overestimated their FTP and/or their diet isn’t high enough in carbohydrate.
I have taken the liberty of bolding the key word here. These are workouts, not noodling around that some like to suggest “endurance” training is.
I just go by perceived exertion.
PPP: if it feels hard, it is hard.
…did I do it right?
My problem is that I’m late to cycling, in my late 60’s and retired, so to all practical purposes have unlimited time to ride my bike and I’m still trying to figure it all out so I can get fitter and better without feeling knackered all the time whilst still enjoying the long group rides with my friends. I’m also definitely not built as a cyclist!
I find your contributions on here incredibly useful but still confusing sometimes.
It may or may not be tangential, but when 90 minutes at 70% of ftp feels hard (generally ‘a slog’) that is, for me, a 100% reliable indicator that I need a rest week.
In ERG mode Normalized Power is approximately equal to average power, therefore to get an IF of 0.75-0.85 for a “moderate intensity filler workout” the power target needs would need to be set at 75-85% FTP?
Your math is correct.
How long of a training session at approx 85% FTP (indoor erg mode) would you still consider to be “endurance” work? And thank you for being so generous with your knowledge.
I’m not really sure that I understand your question.
But, in my own case I would do 1 h at that intensity as a “moderate intensity filler workout” between more strenuous sessions, or up to 2 h if the weather prevented me from getting outdoors on a Saturday or Sunday.