Workout

Warm-up (600)
400 swim
200 kick

Set (600)
600  reverse IM 
...50 drill/50 kick/50 swim 
...free/breast/back/fly 

Set (800)
4 rounds 
4 x 50's choice 
#1 on 1:00 (Last 12 1/2 HARD) 
#2 on 1:10 (Last 25 HARD) 
#3 on 1:20 (Last 37 1/2 HARD) 
#4 on 1:30 (50 ALL HARD) 

Set (800)
2 rounds
4 x 100's on 2:00
...d1-4

Cool-down (400)
200 kick
200 EZ