Originally Posted by Zero7

Oh, looks like they're called "Peak & Fade Power Intervals".

Anyway, they're supposed to be max watts, but these are pretty easy to do without a power meter. You just accelerate as hard as you can, then try to maintain. That's why they suck, because there's no "get to this level and sustain it." Instead it's "if you can go any faster, GO FASTER." Your power (speed) will fall after the first 40 - 60 seconds, but you keep pushing. And keep your cadence over 90.

Here's the actual description from the book, The Time Crunched Athlete: These intervals start with a big acceleration rather than a gradual increase in intensity. I want you to go all-out right from the beginning and keep your power output as high as possible as the interval progresses. Because of the hard acceleration, your power output will gradually fall after the first 40 - 60 seconds of the effort. That's expected and perfectly normal; just keep pushing.

Cheers