I’m out over my skis on this comment due to not being a physiologist, but…
…I’d bet more people on TR are glycolytic rather than oxidative athletes … and I think the training plans likely exacerbate this skew due to their preponderance for intensity.
And I think if you are a glycolytic “sugar burner” your anaerobic contribution to the ramp test will cause it to over estimate your FTP.
Is this sound reasoning at all?
True.
Unfortunately TR has to do this stuff at scale, and so they really need a good quick field test to get everybody up and running without having to provide guidance like a coach would. It’s easy for guys like me to say “har har I’m so smart I use both tests” but getting a large user base to do that AT SCALE is a shit show, at best. I feel for them in that way. Zwift doesn’t care if you mess up you FTP, it’s not the game they are in.
One problem is that by using FTP you are really threading the needle. How many times have we heard 10% under is better than 2% over?
As individuals or ppl who are coached, some combination of the common field tests are just fine. But for TR, might be better off (although now certainly too late) to anchor training off of a metric that falls well below the point at which you “fatigue precipitously but below which you can go much longer”. So “we recommend you use the very awesome TR-TP, or trainer road threshold power, we have seen many athletes blah blah…”. And then TR-TP metric is actually somewhere in 80-90 IF range.
Guys like @DaveWh know how to adjust for this needle threading, as it were (and I’ve done the same trick in the past…be conservative), but as he stated it takes time. Why not just introduce newbies (heck, even old timers) to a lower (even made up) level of intensity as an anchor.
If I see 250w go to 275w with a block of training, who cares if that was FTP or 90% of FTP. Just get most of the TR users in the middle or to the right part of the FLAT part of the PDC, using one test
Neither MAP nor 20min does that without error.
Right now it skews to the left.
Right, it probably seems like it because the folks posting aren’t a random sample.
The other possibility is that 75% is too high even on average, but that seems unlikely based on Stern’s data.
If I used .73 of ramp my FTP would be 50 watts too low. The ramp test isn’t always high, for some like me it’s quite low.
Maybe I’m missing something, but the anaerobic work for the 20 minute test seems to grow linearly with FTP while it grows quadratically for the ramp test.
Shouldn’t the ramp test thus be better at removing the benefit of a higher anaerobic capacity after a certain FTP?
The answer is essentially in the correction factor: 95% vs. 75%.
Suppose your “true” FTP was 250 watts, and that your anaerobic capacity was 10% higher than average.
Instead of maintaining 250/0.95 = 263.1 watts for 20 minutes, you’d be able to maintain 264.4 watts, and your FTP would be overestimated by 1.1 watts (i.e., 95% of the difference between 264.4 and 263.1).
During a ramp test, however, instead of reaching 250/0.75 = 333.3 watts, you’d reach 341.6 watts, and your FTP would be overestimated by 6.2 watts (i.e., 75% of the difference between 341.6 and 333.3).
TL,DR. The shorter the test, the more important intraindividual differences in anaerobic capacity become.
As I’ve said on this forum many times…and posted data to support the assertion…setting FTP at 75% of MAP might be true for a good many riders but 75% is probably just the mean value of a normal distribution. TR doesn’t tell us what the standard deviation of that distribution is!
Which is exactly the point of that blog. Reading between the lines I think this blog is telling us that, based on the author’s review of a great many data sets, standard deviation is on the order of 2.5%. So there will be an unlucky 2.2% or so of riders with actual FTP less than 70% of MAP. Ouch. Those first few weeks of sustained power build are going to crush.
Based on data I’ve seen, standard deviation increases as cycling experience decreases. Among a more inexperienced cohort there are an unfortunate many riders who have actual lactate threshold power that is less than 90% of TR FTP (75% of MAP). Those riders will find it very, very difficult to complete TR plans.
That doesn’t mean the ramp test isn’t a good test. It is a good test. Setting FTP to 75% of MAP for all riders is just too lazy. That’s all. It’s a good business decision…not a good coaching decision.
While your points may be valid, that graph doesn’t really show what you think it does.
@Brennus I agree with this and is what I’m trying to get at with my little “trainer road threshold power” thing above.
So given this, what would you do if you were in TR shoes? (moving forward)
That is some useful information. I would be inclined to take the72%, not the 75%, though I can complete the SSB intervals ok, but probably at a slightly higher effort level than desirable. Where I struggle is the vo2max. Which does suggest my current FTP is 7-10 w too high.
I am also a cx and mtb racer, but think it is worth doing the 20 minute test which I think is perfectly do-able. The 1 hour one is harder, because you need a good idea of how to pace yourself, and many (of us) might be tempted to set an unsustainable pace at the beginning.
I do not see the problem with the 20 minute test. Surely everyone on here actually does 20 minute sessions of ss training, so it’s not that hard!
I don’t think your performance with VO2 max workout necessarily indicates a FTP that is too high. VO2 max intervals in TR are a best guess (120%) and you’re suppose to adjust the intensity up/down to suit you. Your V02 max may be 116% or 122% of your FTP, it’s all individual. Notes from my V02 max workout:
Can you provide some details as to how you do this? Do you use your MAP the same way as we use FTP for lower intensity intervals ie. a certain percentage of MAP for 4 minute intervals, a certain percentage for 2 minute intervals etc.?
Bruce
Do them by feel in the range of power you assume you can do them. With vo2 max it is very simple - pedal as hard as you can for a given time:) I started this season doing a lot of my workouts by feel and it is liberating, you learn to pace the efforts and often you are surprising yourself.
I’ve done ramp and 20m tests and have gotten very, very similar results.
In the end, none of these are right. They change daily and hourly.
The differences in results can be smaller than the error rates in trainers.
People spend way too much time fixated on which test is best, when the are all variable.
You need something to base your training off of. The ramp does this in a simple way that is easy to repeat and retest without derailing training.
I’ll keep doing the ramp and maybe I’m off by 1%. Doesn’t matter in the slightest to my training. My day to day is far more variable than the test I take.
I think we both probably agree this would be a trivial problem to solve in a 1-on-1 coaching relationship. 
You could also do it in a more automated fashion using a follow up workout after the ramp test & a trick I learned from a Bulgarian weightlifting coach about 20 years ago. Just a way to normalize HR observations & then observe HR response at a workrate you think is LT. A very bulgarian approach…let’s see what you can do today and then set your workout based on that. Anyhow, if your HRR pinches off…well…that wasn’t FTP. 
While the TR Vo2 max intervals are based on FTP, you really shouldn’t use FTP as your guideline for intensity above FTP. While it is a good start, you may need to adjust based on RPE. Chad has mentioned this a few times on the podcast and Coggan came out with a paper several years after his book on power meters that changed the intensity of his training intervals above FTP to base them on RPE.
Bruce
@bhammond58
My 30-30s are at my MAP +/- 5%.
FTP 300w
MAP 405w
So SweetSpot is 88-92% of 300w. Tempo, other sub-threshold intensity same. Based off 20min test FTP.
So the fact that those 30-30s are 130% (or whatever it is) of FTP is not important.
I’m sorry I cannot translate those to TR workouts. That would make what I’m saying a bit clearer I think. But when the workout is designed to target VO2max I don’t put in my FTP and take a percentage of that. I take a percentage of my MAP power (400 in example above) to do those intervals.
Agree with your answer to @Lydiagould. Her FTP isn’t necessarily wrong because she has to adjust workouts well above FTP. Just base VO2max workouts off of a number that is closer to power at VO2max, not FTP. Then use FTP for all else.
Are you referring to the iLevels in WKO4/5? If so, they’re still power-based targets, not based on RPE.
yep. No doubt.
Interesting. Yeah maybe a follow up workout right after ramp. The “TrainerRoad Validation protocol”, or however they would market and document it. Basically a formalized way of doing what they (and many on the forum) often recommend “adjust based on how you feel with the workouts”. For many (certainly for me a few years ago), I don’t know what I should be looking for in terms of HR, power, RPE. How do I know SweetSpot feels like this, threshold feels like that. The numbers under threshold behave like this, slightly above behave like that.
Aren’t all efforts best based on what you can actually do, and not on FTP?