That’s what the PDC does with far more detail.
Did I say it was the epitome of training data or the most basic?
A PD curve absolutely tells you more, but there isn’t one in the TR app (at least when I left) and it’s way more complex than the average rider needs. IIRC, back in the day Ivy talked about not caring what her FTP was, and just leveraging PLs—it might not be been FTP, but she definitely talked about using PLs more.
That being said, I use WKO, so it’s safe to say it was too simplified for my enjoyment. But that doesn’t mean it can’t be leveraged by those who want to be less bogged down by training theory.
We need more info!!
Thank you.
Guess it needed an update!
It’s literally on TR’s blog.
…sometimes, your relative strengths and weaknesses can change, even while your FTP stays the same. That’s where Progression Levels come in, tracking your current capabilities in each power zone to monitor every aspect of your cycling fitness.
I think that blog post could do with a tweek 
The link between an athletes progression levels and capabilities is indirect.
All they indicate is that what workouts have been completed.
If two athletes with wildly different capabilities decided for some reason to do the exact same workouts for a while then they would end up with the exact same progression levels.
If the athletes are on a plan with different prescribed workouts then the progression levels would start to diverge but even then it’s only the relative progressions - not actual capabilities - that will be shown.
If an athlete who is really strong at VO2max does a few months of just sweetspot then their sweetspot progression levels will be high and their VO2max levels would be low …. but they could still be more capable at VO2max relatively than sweetspot.
Agreed. Also with PLs I think it’s important to make the distinction between an effort that is part of normal training & an effort that is well beyond that, such as one requiring both a taper before & considerable rest afterward. Or oppositely, someone on the old SSB HV plans (who’s doing sweetspot literally every. single. day) probably has deflated PLs (or a deflated FTP) in comparison to their self doing sweetspot just twice plus one threshold-or-above each loading week. I would argue that one’s PLs are only valid if the work that led to them is part of a normal, uninterrupted training cycle. Not first workout back after a recovery week then needing four days to recover. This is part of why I suspect WLv2 has been so hard to get over the line.
Then there’s the implications for a set of PLs being offered for that big hero ride on the weekend. Jonathan went on the podcast years ago & described our PLs as being like our video game character’s superpowers, (& I think it can feel that way!) so naturally I think it seems attractive to chase them, perhaps encouraging us to go out & do big, unstructured efforts, ignoring that they’ll likely interrupt our training.
I went in an informal race on Wednesday. Whilst it wasn’t a “big” ride, it fatigued me enough to fail a proxy for a reduced version of the scheduled workout which I attempted immediately afterward (
d’uh!), &… well TR passed me-but I call it a fail-on today’s (Friday) workout in which I couldn’t hold the power targets for the last half of the last interval. I probably don’t deserve a PL for the race because it interrupted my next two interval sessions.
I’m less inclined to chase PLs now because I feel their role has been made redundant by the big ticket items that were released in the last three years: detection of FTP, workout selection, & plan builder, all powered by AI analysis. I think PLs were a great idea when they were first released in the absence of this trained AI stuff. But PLs as currently presented seem a bit primitive in comparison. It would be a brave move but I think TR could get by without them. If PLs are staying then I think they need an update. I’m really interested to see which way TR goes with it all. Exciting times! 
Probably important to remember that PLs are not some scientifically validated result. Just a tool that TR created that made sense in their eco-system. You wouldn’t go to some other coach and tell them your PL scores.
As someone that creates my own plans on TR, I use the PL values as a way to either progress my hard workouts or keep the easy ones easy. It is way simpler than trying to compare TSS or IF or anything else given how many workouts there are. I don’t care whatsoever about trying to lift my PL’s just for the sake of “high scores” in my game.
TR suggested a 9.4 Vo2 Max (Bolton Brown -1) today which was double by current PL. I went with, but I was obviously nervous. To the system’s credit, I was able to finish, but the first set of 2m intervals were all out. Completing is prompted an AIFTP bump of 1.8%.
All in all, not sure. While I could complete the workout, it felt more like dropping a race effort into my training, especially in December, but it also didn’t misrepresent my capabilities.
This is similar to what I’m experiencing after signing up two weeks ago. It has me doing a 7.9 SS workout already, which is 94-97% of FTP for pretty much 50 minutes straight (tiny 15 second breaks every 10 min). Can I do it, yes, but the AI seems to be testing a too low starting FTP by giving me higher level workouts. If I complete this for say a “moderate” post ride feedback, will the AI just bump my FTP or keep pushing the PL?
On the 9.4 I did, I got the same WL recommended whether I rated it very hard or all out.
Hopefully they don’t “throw the baby out with the bathwater” on PLs. They have utility for me in judging progression. I appreciate that Trainnow can spot where PLs aren’t “right”, but a jump from 4 to 10 is still substantial, and I might want to take it more as guidance that I should try Stretch or Breakthrough.
I think workout levels will give you all the relative difficulty information you are looking for, though they could use some fine tuning with the help of AI.
Progression levels, with their formulaic decay, certainly aren’t accurately telling us what we can do. If they revamp them to show what the AI would recommend as a workout on that day, then they would be much more helpful.
I think it will a predicted FTP at the end of training blocks…….or some sort of future FTP forecast.
Now what would make you think that? 
I love their style!