Workout

Warm Up (600)
Swim 12 x 50's on :50

Set (600)
6  x 100 on 1:45 
...kick/swim

Set (2000)
4 x 200 build on 3:00
…80-85%
4 x 150 on 2:00
…descend 2,4 
4 x 100 hard (90%)
…on 2:00
4 x 50 on :45
…descend 1-4

Cool-down (200)
200 moderate to EZ