Originally Posted by
rubiksoval
Andrew Coggan and countless others would disagree with you on that. Working that boundary between zone 3 and 4 (upper z3, lower z4) gives you one of the greatest bang for the buck workouts you can get, and once that's repeatable and sustainable for quite a while. It's generally called "sweetspot" training and is generally around 88-95% of FTP.
I consistently put more time in that zone during the winter months than all the others when I'm only getting in 7-8 hours a week.
Gives an excellent training effect. Same for just straight-line z3. 60-90 min steady in z3 is a very nice workout.
That is true, and I do the same, but it's all about training volume and goals. Probably for low volume and the goal of general fitness, sweetspotting is very good. I supposet there are good arguments to be made for highly polarized training even at low volumes, but those are fine point distinctions most relevant to specific athletes, some of whom may respond better to either method.
In short, there's more than one way to catch a fish.