Hub · power models
Power Training Zones
Power zones for cycling and running: Coggan FTP 7-zone with Sweet Spot, Critical Power and W′, and Stryd running power. Anchor every watt to a real test.
FTP Calculator & Cycling Power Zones
Functional Threshold Power (FTP) is the highest power you can hold for about an hour. The Coggan model sets seven zones from it: Endurance (Z2) is 56–75% FTP and Threshold (Z4) is 91–105%. At an FTP of 250 W, Z2 is 140–188 W, Z4 is 228–263 W, and Sweet Spot is 220–235 W.
Critical Power Calculator (CP & W′)
Critical Power (CP) is the asymptote of the power–duration curve, the highest power you can sustain almost indefinitely. From two maximal efforts, CP = (P1·t1 − P2·t2) ÷ (t1 − t2) and W′ = (P1 − CP)·t1. A 300 W 3-minute and 250 W 10-minute effort give CP ≈ 229 W and W′ ≈ 12.9 kJ.
Running Power Zones Calculator
Running power zones anchor to your running Critical Power (CP), not cycling FTP. The two are not interchangeable. Stryd's five-zone model runs from Easy below 80% CP to Repetition above 115%. At a running CP of 280 W, Threshold tops out at 280 W and Repetition starts above about 322 W.