Swim Swap

Missed my swim on Sun, so I swapped today's 500yds for 4x400yds. I rested 2 min between sets and tried to stay within the proscribed 4 seconds, but I came out with some weird times: 6:50, 7:11, 7:16, 7:20. The 6:50 was blazingly fast for me, but I swum my little heart out on the others and couldn't seem to keep pace. That said, it was definitely 100% effort...