Steve hasn't had enough racing during the pandemic to keep his ego in shape;)
Years ago when I could swim I sometimes did a related set.
Nx200 scy fr
Start on 3:00 interval. Decrease interval by 5s each 200. See how far you can get before you miss the interval. As I recall my best efforts I would come in right on 2:25 on #8 and making the interval on #9 was hopeless.
I am unsure if I can still swim today. If I can, even the 3:00 interval would likely be impossible.
