Hi all,
It’s my first time on this forum so please forgive me if this topic is in the wrong place. For the tl/dr mode, please scroll down 
So a short introduction, since approx febuary 2020 i’ve been using my racing bike. Only outside untill the weather got worse and i bought a KICKR Snap approx a month ago. by now i’ve racked up approximately 5000 km outside and 430 km in Zwift. Today i’ve tried the “FTP test (Shorter)” workout for the first time. The average power output during the 20 minute FTP measurement was 250 W and resulted in a FTP of 241 watts. The interesting part in my opinion is that my estimated FTP by zwift was 273 W before this measurement. I think the problem i’ve got is that my cadance is normally relatively low (80-85) when i’m cycling normal routes (on zwift, only purchased my cadance meter a couple of weeks ago). During the ‘free ride’ in the workout I run into the problem that i have to uphold a higher RPM than usual (90-100). Is it possible to change the settings for the target RPM in the free ride/FTP test in a workout? Or could the problem be something else that i’m missing? after the 45 minute workout i was tired for 1-2 minutes but after this everything was fine again, since it was more a challenge in spinning faster than usual than it was a power-test.
Hope the story makes sense and thanks in advance for any possible solutions/input.
Best,
Jochem