Notes
Warm-up for fifteen minutes. Next, shift to a relatively large gear, something that you can push hard, with a lot of watts, for thirty seconds.
The session goes like this, after warm-up. 30 seconds easy pedaling, 30 seconds hard effort. After 30 seconds hard, 30 seconds easy pedaling in the same gear, and then repeat. 30s easy, 30s hard, 30s easy, 30s hard, etc.
Do this pattern for 20 minutes. When down, ride easy for 15 minutes, and then endurance for 30 minutes.
My HR monitor seems to be flaking out a little at the beginning of these cascading intervals. It did the same thing last week.