True, finding the correct intensity is key for progress in your plan…
If you are well trained and starting from level 1, there is no real challenge in the workouts. (like I experienced)
If I look at level 6-8 workouts, I think i could do them, but it would be (very) hard, and not really sustainable on the long run…
What I did notice, when I got a FTP bump (only a few watts) TR throws me back 2-3 levels…
Then i quickly adjust it back to previous levels (or slightly under) where I think it is still manageable like before…
I’m not chasing higher levels in general, but if I do now 12 minute intervals at FTP, TR will throw me back to 5-6 minute intervals, even when the wattage increase is only 5 watts.
Im some workouts like Threshold/Vo2Max/Sprinting it is ok to push limits, just make sure that you finish the workout without complete exhaustion after the last interval.
Just having experience on the different kind of workouts and make sure you know what you CAN do…
Like my schedule tonight, I have the workout Avalanche Spire +3 (Threshold 5.1) 7x for 8 minutes under/over FTP… It will not be an easy workout, but I feel fit, and I know I can do it.