A couple of things, from one diesel to another:
- my understanding is that ramp tests are designed to predict max aerobic power, and from what I’ve seen the TR ramp is pretty good at setting a ceiling on 5-min vo2max power
- TR uses 120% work intervals for vo2max, based on the assumption FTP is 78-85% vo2max power and more precisely 120% level is for someone with FTP at 83% vo2max power ( 1 / .83 = 120%)
So if you fall into the 78-85% bell curve, then vo2 work at 120% is challenging but not crushing.
- its really easy for me to ‘detrain my vo2max’ and when I do its not uncommon for FTP to be 90% of vo2max (based on 5-min best power from ramp test, and FTP from sweet spot or TT effort)
- When FTP is 90% vo2max, I’m an outlier from TR vo2 work interval assumptions and doing the same math as TR, my vo2 power for intervals should be 111% ( 1 / .9 )
- 111% is achieved by reducing intensity down to 93% for vo2max workout that use 120% work intervals ( 111% = 120 * .93)
- before understanding all the above, I independently confirmed setting intensity to 92% or 93% to be my max repeatable vo2 power when in a detrained state (FTP = .9 * vo2max)
If your FTP is close to 5-min vo2max power, then the default 120% VO2 work intervals will crush you and its time to dial down the intensity.
I’ve also “failed” some of my ramp tests, however I like doing the ramp test to assess 5-min power, and another test (or manually estimate) for FTP. That way I can keep track of my vo2 weakness relative to FTP. I’ve been able to raise vo2max such that FTP is 83-85% and when I do the ramp test is a good predictor of FTP. But sometimes even at 88% the ramp test gives a good estimate of FTP. Haven’t really figured out why some of them fail, but unlike you when I fail its because I can’t catch my breath (and not legs).
Another interesting post is from @stevemz over on this thread: Ramp test under achiever - #28 by stevemz
Hope that makes sense, and helps.