Hub · pace models
Pace Training Zones
Pace-based zones for running and swimming: Daniels VDOT running paces and Critical Swim Speed (CSS). Turn one race result into every training pace.
VDOT Calculator & Running Pace Zones
VDOT is Jack Daniels' single running-fitness number, combining VO₂max and running economy from one race result. A 5 km in 20:00 gives a VDOT of about 49.8. From that one number the model derives every training pace, Easy, Marathon, Threshold, Interval and Repetition, so all your zones come from a single race.
Critical Swim Speed (CSS) Calculator
Critical Swim Speed is your swimming threshold pace, found from two time trials: CSS = 200 ÷ (t400 − t200) in meters 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.
Running Race Time Predictor
A race time predictor estimates your finishing time at one distance from a result at another using Riegel's formula, T2 = T1 * (D2/D1)^1.06. Enter a recent race, such as 45:00 for 10K, and it predicts roughly 21:35 for 5K, 1:39:17 for a half, and 3:27:01 for a marathon.