Should I Increase the Power With FTP Work?

When I assign FTP intervals to people, I almost always go with increasing time rather than increasing power. And this makes sense too, because this provides a very natural route for progressive overload in your training cycle. So if you could do two by twenty minutes at 240 watts, and your FTP is 250, my next progression would be to say do one by forty minutes at 230 to 235 watts. To me, that would be just as good as doing two by 20 at 245 watts.