My guess is only upsides. My conclusion is the system is half baked. It lowered my FTP from 306 to 298, glitched to 302 a few days later, then I did a 90 minute Zwift race up Ven-top, holding 305w for 40 minutes, dropping to 298 at 60 minutes, and 289 at 90 minutes. All that while keeping my heart rate average at 162, just under my LTHR of 169. Thanks to this effort my intervals.icu eFTP is 304w based on 26 minutes at 317w, and Zwift post race said congratulations, your FTP is 305w now. I did later change it back to to 302w to honor TR, but found I can no longer backfill workouts to reflect that my race effort closely aligns with a level 9 threshold workout.
Edit:
As far as my profile. I’m a 41 year old who has been doing NYC crit races with CRCA in central park and prospect park since 2016. My training volume in the span has been all over the place.