It was in 2016 that spike sets last featured in my routine but today it felt to be the right thing to do. Actually it wasn't. I didn't want to swim for much over 30 minutes so started with 8 recovery lengths (so the sequence would be 8+2, 6+2, 4+2, 2+2, 2 cool down) giving a total of 1000m. My plan was to do as many of the recovery lengths as possible with bilateral breathing.
Quite early in the session I could tell that I was still tired from yesterday's swim. The 'fast' lengths were terrible at 2:20min/100m at best! For the recovery lengths I couldn't maintain the bilateral breathing even at a slow 2:40min/100m and ended up pausing in a few sets.
Anyway, I completed back-to-back swims again and put some effort in for both.