One of the most common sets coaches use to establish a swimmer’s base is to have them swim 10 x 100 at the fastest pace they can hold “comfortably.” This doesn’t mean their absolute threshold pace for 10 100s. “Comfortably” means getting about 5 to 7 seconds of rest between each 100.
300 Easy
4 x 50 as 25 Fast / 25 Easy
Start a stopwatch. Then, swim:
10 x 100 comfortably with 7s rest
Stop your stopwatch. Divide your time by 10 to determine your base pace.
200 Easy