I don’t know if it’s allowed to post screenshots of the workouts, so I’ll describe them:
Workout 1:
Tulsa:
Endurance 2.7
1:45 hrs
60 TSS
IF 0.59
Workout 2:
Endurance 4.1
Beech:
1:00 hr
46 TSS
IF 0.68
How is this possible? Sure, Workout 2 has a bit more intensity, but Workout 1 is almost twice as long and has 25% more TSS, yet it has a 1.4 lower Workout Level. After all, both workouts are pure endurance workouts in Zone 2.
I’ve already read the support article, but it didn’t really help me in this case. Maybe someone could explain this?
Does that mean I would make more progress with 1 hour of training than with 1 hour and 45 minutes?
We don’t know the TR proprietary WL equation. It is also important to remember that WLs are not a scientifically proven training principle. It is a tool that TR created to help within their ecosystem.
The biggest clue is the different IF of those workouts. IF is a non-linear average of %FTP. And %FTP is non-linear for training stress / fatigue. Most people can ride at ~85% of FTP for twice as long as they can at 100%. It’s similar as you go further below or above FTP.
That’s why TSS was invented. The idea is to roughly figure out how difficult a ride is. But even then it’s not perfect. And you can’t really compare VO2max TSS to easy ride TSS. VO2max will be more fatiguing.
TR came up with their workout levels as a useful tool for their training system that tries to compare only workouts in the same training zone.
Not all endurance is made equal. If I were to ride at 0.59 IF, that would be 30 watts easier than 0.68 IF. That’s a significant difference in intensity (and energy demand). There’s a difference in TSS due to duration, but completing workout 2 should still feel harder than completing workout 1. At least to me it would.
