I was not meaning to be precise, but was riding over 600 miles a week back then and had just one speed - just under threshold. I read about some pros in the 80s who trained 700 mile weeks to prep for the tour and figured I needed to do the same for my 45 min crits and 20 mile TTs, but I was going pro too I was young and had no life and no clue about anything. I started out a 20 mph on each ride and then would hold it until I dropped and then ride home. So while I am sure I was not at 90% FTP for the whole ride, every ride, that was my style and I would categorize every ride as an SST, every day - go just under as hard as you can and hold it. I only trained with a speedometer, my final week of training before blowing a gasket was over 700 miles ... an no I did not average 20 mph for the entire 700 miles, but that was just my only ride goal - and I would say I was near SST for most of my rides. I was not riding smart.

My point was to place a dig on blindly following advice from pros without a complete package, and that SST training should be longer than 20 minutes and not considered an interval, in my book. Neither of which was really needed at the time, but I added my 2 cents anyways.

So yes I am the guy on the internet who rides for 4 hours at SST and then sprints at 40 mph ... and of course the answer to that is no chance.