Bk in workouts?

I assume backstroke 

usually the most common short hand is:  Bk = backstroke. BR = breaststroke, FR= free.

Thank you Allen and Camillevh1.

I have the same question as ZNMXZ.  

We understand that the abbreviation bk itself stands for backstroke.

But in the context of the emailed workout listed the letters bk that come after the words warm up are confusing because what follows is 200 Free which indicates the stroke to be freestyle. The letters bk also follow the title and each segment of the workouts that I am emailed and the stroke style is listed after the distance.

Why is bk entered after the title and each segment of the workouts when stroke style is listed after each distance?  Perhaps someone who works with USMS training section would be able the help clarify?

ZNMXZ it appears those are the initials for the person writing the workout Brenda Kottke (bk) for the Basic Training workouts in the USMS Workout Library.  www.usms.org/.../ladder-again-bk-18253

Thank you.

Ah!  That makes sense.  I had the same qeustions from looking up workouts.