yeah 20 min test takes a lot more training in the sense that standardized testing takes training. i have definitely realized 15 mins in that i could test higher if i planned better.
im sure some ramp test analogue that takes a bit longer could bridge the gap there but 20 min tests are torture and encourage you to go too soon or go too late imo
FTFM
yeah at that point i’m quitting immediately at 15 minutes when i realize my folly
I’d do the ramp test to get an FTP guess, if that guess is way off and the resulting workouts are too easy or too hard, you can always test again. Or manually nudge your workout FTP number in either direction.
And FWIW ramp tests can be a pacing challenge too - I just did the zwift one this morning and after the fact, think I could have gone another minute there 
The best way for me to push myself and make breakthroughs is having another rider to chase down, so I’m not staring at numbers that I’ve already decided I can/cannot maintain.
If I’m coming off a long period off the bike, I’ll do an 8 minute FTP test to set a baseline. Then 6 weeks later, I’ll do a 20 minute.
I did a ramp test but i feel like it overestimated my ftp as threshold intervals feel way too damn hard, like i can’t more than 4 min at my ftp.
But I’m too proud to lower my ftp so just hoping my fitness catches up
I tried trainer road this winter instead of zwift, and it’s having a bigger impact on my fitness. I seem to have a better time just doing intervals while watching tv than I did in a virtual environment with other people. I find the progression data more engaging, which led me to check out intervals.icu. Now I’m in full on data nerd mode and will be needing to get a power meter for my outdoors bike before spring!
I had the same experience with Xert. Zwift was nice to build a habit, but all the superfluous stuff got boring fast.
i did the test and it raised my ftp. yay? now i can’t do the D races anymore. i did a C race today and actually hung on for 3 of 4 laps which is a new record for me. now my legs hurt real bad.
I went up alpe du zwift too fast and I’m locked out of C. Ain’t no wait in hell I’m winning a C race (unless it’s a pure climb), let alone not getting instantly shelled in B.
they definitely need a thing you can use like 2-3 times a year “i swear i was just on a banger today, please don’t update my ftp based on this one random outlier good performance”
I mean, i did it even faster a month later… but I’m outgunned trying to hang on on the flat, too light, lower absolute power.
have you considered getting heavier and increasing your absolute power
no
this is a zwift flaw IMO. their algorithms make it really hard for anyone on the lighter side to hang on the flats because the draft assistance is not as good as real life. it’s terrible for smaller women, they basically can’t do open group rides without getting dropped.
“double draft” events are much more realistic in this regard.
when i was in good shape, i was firmly a “B” off watts/kg, but i could barely hang in a flattish race.
guess I’ll just try to get my AdZ time under 50min instead. (probably get cat enforced to A then)
why isn’t the draft as strong as real life? what’s the reason to do that?
Zwift drafting mechanics are absolutely whack.
that’s why i did so badly in that one race i did! i swear!