These are very effective.
They are all the same workout, except for number of sprints. In order of least to most, it’s Birling, Detling, Charing, Titsey, Rowdow, and Stangate, with 4, 5, 6, 7, 8, and 9 sprints, respectively.
IME, I get diminishing returns after 6 (Charing). The idea being, if I can do 7, 8 or 9, I could have done 5 or 6 at higher power, which IMHO is more beneficial for this type of workout. YMMV.
I do them seated at 120-135RPM cadence. Doing them consistently, 3-4X a week for 4 weeks noticeably improved my 30s to 3 minute power, as well as my ability to repeat 5-15 second efforts. As expected, they did not improve my max power.
As the workout text says, these need to be scaled to your ability, which is different for everyone. If anaerobic ability is one of your strengths, as it is for me, you’ll find yourself bumping up the intensity significantly. 120%, 130%, or higher is all fair game with these.
It’s easy to use some mental tricks to excel at these workouts. For one, you can tell yourself that you can do anything for 20-30 seconds. Second, because the efforts are short and few in number, you can feed your desire to hit vanity numbers. For example, why settle at 590 watts when you can bump it up to 610? Or 690 to 710, or 790 to 810?