"Go slow to get fast" was originally pointed towards me, and I said "not really". I say this because when I think 'Go slow', I think a level 1, recovery type ride. I do see guys riding around at 15 mph with a tailwind. That isn't going to do a damn thing for speed. There is a threshold that you have to reach for the training to be worthwhile.

Riding at the top of zone 2 is effective if done for long time frames. I'm talking a couple hours at a time. One book likens it to Chinese water torture. At first it is absolutely nothing. After a while you notice it. After a while more, it becomes genuinely difficult. Here's the deal. It takes volume, but with sufficient volume it is really effective, and since recovering from such a ride happens quickly, it's physically possible to reach the appropriate volume.

When you start cutting the ride time down, then you need to turn up the intensity. SST work is a perfect middle step to build phases and good in build phases to push up the FTP without pushing the rider into an over-reached condition.

Now to answer Fordfasterr's question. If I had to put money on a rider in a crit that has trained a reasonable volume of SST work or a reasonable volume of VO2 work with no middle ground which would I choose?

Over the course of a single race, I'd probably stick my money on the VO2 trained rider and hope he could stay in the draft. Over the course of a season (say 10 races), I'd stick my money on the SST guy.

Developing aerobic fitness and a strong FTP is absolutely essential for maximum fitness and in the end will really pay dividends over the long haul.