200 warm up – just cruise
3x50s moderate w/15 seconds rest
3x50s faster w/ 20 seconds rest.
3x100 w/ 20 seconds rest – “descend” this means swim each one faster: #1 easy (note time, rest 20 sec), #2 faster (note time, rest 20 sec), #3 fastest (note time, rest 20 sec).
20 seconds after you finish the last of those three 100s then swim an EASY 200 – so easy that you continue to recover even while swimming. That’s one round – do three rounds.
If we wrote this out as a math equation it would look like this: 3x(3x100 descend w/ 20 seconds rest, then a 200 easy).
3x50s easy w/ 30 seconds rest.