This sounds “not bad” from an intensity standpoint due to the long rest intervals. It’s deceptive, however, because it’s more of a muscular endurance workout than a “cardio” workout, and it’s quite challenging due to the high number of intervals.
My strategy was (after the first piece) to try to keep the splits below 1:30, and to start spinning the wheel with 10 seconds left on the rest interval so that I could come in at full speed. I also did it on a light drag factor (111) to simulate racing in an eight vs. a small boat. I figured that rowing at 40+ strokes per minute, each interval would be about 25 strokes of power.
I was able to stick to my strategy for the first 8 intervals before my legs started to get slow in the last 100 meters and I dropped over 1:30 splits. Interestingly, I must have been burning glycogen in the first 8, because I didn’t really get “winded” until the last 4 intervals, corresponding to when I started to slow down. Interesting how you could see the transition between energy systems explicitly in this workout.
I think this workout would have been “easier” in a way on a higher drag factor, as the limiting factor seemed to be not strength, but the ability to retain a quick impulse with the legs at 40+ spm.
Here’s how it shaped up. You can see that the first interval was slow due to the static flywheel at the start, and the splits dropped off at interval #8.