In her latest workout, Triathlete contributor Sara McLarty has us swimming fast/easy 50s and some hypoxic pulls.

A:

400 choice/200 pull/200 kick
8×75 @ 1:15 (kick/drill/build by 25)
10×50 @ :45 (25 FAST!/25 easy)
600 pull (3/5 breathing pattern by 100)
20×50 @ :40/:60 (1 FAST/1 easy/2 FAST/1 easy/3 FAST/1 easy/etc)
400 pull (3/7 breathing pattern by 50)
200 cool-down (50 frog/150 choice)
*4100 total*

B:

400 choice/200 pull/100 kick
4×75 @ 1:45 (kick/drill/build by 25)
8×50 @ :60 (25 FAST!/25 easy)
400 pull (3/5 breathing pattern by 100)
20×50 @ :50/1:10 (1 FAST/1 easy/2 FAST/1 easy/3 FAST/1 easy/etc)
400 pull (3/7 breathing pattern by 50)
200 cool-down (50 frog/150 choice)
*3400 total*

C:

300 choice/200 pull/100 kick
4×75 w/ :20 rest (kick/drill/build by 25)
6×50 w/ :15 rest (25 FAST!/25 easy)
400 pull (3/5 breathing pattern by 100)
10×50 w/ :10 rest (1 FAST/1 easy/repeat)
200 pull (3/7 breathing pattern by 50)
200 cool-down (50 frog/150 choice)
*2300 total*