Originally Posted by mollusk

Not trying to be snarky, but what is the point of it other than to break the monotony of Z2 base riding? I keep seeing posts about doing 2x20's at fractions a fair bit less than FTP and I am at a loss to figure out why. I have always done them above FTP when doing them for effect. Am I doing them wrong?

Throwing some in during a base period just to keep things interesting is fine. I try to throw at least one 1.5 hour SST ride in after a couple of weeks of base and some frisky riding with friends on 4+ hour rides is also a good thing. Base is horribly boring, but it is the foundation upon which you build.