To be specific… the formula I’d use is he following:
- average your weight with 75 kg. For example, if you’re 75 kg, this stays the same. If you’re 65 kg this becomes 70 kg. This accounts for the fact that efforts on the flats require more W/kg if you’re lighter, and races include both flats and climbing.
- Then apply the power limit: 2.4 W/kg, 3.2 W/kg, 4.0 W/kg.
- This is your critical power limit. For any effort in a race, add 2 minutes to the duration, then determine your maximum work for that duration, and apply that to the actual duration (i.e. you get 2 minutes of effort for free). This comes from the critical power formula: APmax = AWC/T + CP, using a typical value that AWC/CP = 2 minutes (1.5 minutes is more typical, but I rounded up).