20 minute field test

I wanted to clear up a little confusion. My training plan came with 20 minute field test at the beginning & end. They have the exact same watts in each. My question is this: How does one know if they improved their FTP if the same watts are being used on each different test? Should I up the watts myself before the last test? FYI I use a smart trainer for these test. Thanks JB

You shouldn’t use a smart trainer for these or any trainer. They are best performed outdoors. You can use your power as a guide, but really should go off feel and not hold back after the first 5 - 8 minutes. If you must use a trainer do not use erg mode. You are trying to determine your FTP, if you knew exactly what to set the watts at on the erg then there would be no reason to do a test. You would know.

In the training plans the field test does have a workout builder and it is set at 105% of your FTP. But use that as a guide and not a end all be all.