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Swimming Training Zones
Pace per 100 m rules. Anchor to Critical Swim Speed (CSS) from a 400 m and 200 m time trial; heart rate is hard to read in water.
Pace
Critical Swim Speed (CSS) Calculator
Critical Swim Speed is your swimming threshold pace, found from two time trials: CSS = 200 ÷ (t400 − t200) in metres per second, and pace per 100 m = 100 ÷ CSS. A 400 m in 6:00 and 200 m in 2:50 give a CSS of about 1.05 m/s, or roughly 1:35 per 100 m, your sustainable threshold pace.
PaceField test→