Workout

Warm-up (600)
200 swim
200 drill
200 kick

Set (400)
8 x 50's build on :50

Set (2000)
6 x 150 free 
...descend 1-3on 2:30 
500 free on 6:30
4 x 150 free on 2:15

Set (400)
8 x 50 kick on 1:05  
...25 hard, 25 EZ 

Cool-down (200)
200 EZ