Critical Power, VO2max & FTP Cycling Performance Tools - Saddle Up Cycling

Numbers don't make you faster, but they tell you where to look.

Find your Critical Power and the size of your anaerobic battery, set your zones from whatever test you did, see where your watts per kilo place you, and follow the season's trend rather than chasing one result. Then go and do the work. Saddle up.

Body weight (kg)

Sex

Critical Power & W'

Critical Power is the effort you can hold almost indefinitely; W' is the battery above it for hard efforts. Enter a few maximal efforts on separate days and it fits your power-duration curve, estimates FTP at 96% of CP, and tells you how long you could hold any power above CP.

3-minute power (W)

6-minute power (W)

12-minute power (W)

20-minute power (W)

Add more durations for a fuller curve

1-minute power (W)

40-minute power (W)

60-minute power (W)

The 1-minute effort is plotted for context but left out of the fit, since the model holds from about 2 minutes up. The 40 and 60-minute efforts are included.

Power-duration curve

Predict power for a duration (min)

Hold this power (W): time to empty

Interval designer

How many hard reps before the tank runs dry, using your CP and W'.

Interval power (W)

Interval length (s)

Recovery power (W)

Recovery length (s)

FTP & Training Zones

Set your threshold from whichever test you did, then read off your power and heart-rate zones and where your watts per kilo sit.

How did you test?

Threshold heart rate (optional, bpm)

Power zones

Heart-rate zones

Workout targets

The numbers you actually ride, from your FTP.

Target watts

The FTP you would need to reach a chosen watts per kilo at your current weight. A power goal, not a weight one.

Target (W/kg)

VO2max & Fatmax

From a single all-out 5-minute effort, estimate your aerobic ceiling and the power at it, plus the intensity where you burn the most fat. Estimates from power, not a lab cart, so treat them as a guide.

5-minute power (W)

Weight (kg)

Power Profile

Your best efforts at four durations say a lot about the rider you are. Enter them in watts and it places each on the profile, gives a category, and reads whether you lean sprinter, all-rounder or time-triallist. It is normal not to land in the same band everywhere.

Best 5-second (W)

Best 1-minute (W)

Best 5-minute (W)

FTP (W)

FTP Progress

Compare two tests and see the change in watts and watts per kilo, the average weekly gain, and a simple forecast twelve weeks on, in a perfect world without the genetics getting in the way.

Previous test date

Previous FTP (W)

Previous weight (kg)

Recent test date

Recent FTP (W)

Recent weight (kg)

Season Tracker

Log every test as you go and watch the line. The trend matters more than any single number.

Test date

FTP (W)

Weight (kg)

FTP over time

References

Chorley, A., & Lamb, K. L. (2020). The application of critical power, W' and its reconstitution. Sports, 8(9), 123.

Jones, A. M., et al. (2010). Critical power: implications for determination of VO2max and exercise tolerance. MSSE, 42(10), 1876-1890.

Sitko, S., et al. (2022). Five-minute power-based test to predict maximal oxygen consumption. IJSPP, 17(1), 9-15.

Venables, M. C., Achten, J., & Jeukendrup, A. E. (2005). Determinants of fat oxidation during exercise. JAP, 98(1), 160-167.

Allen, H., & Coggan, A. (2010). Training and Racing with a Power Meter. VeloPress. Power profile categories adapted from this work.

Estimates for healthy adult athletes, from field tests rather than a laboratory. We can't do the work for you, but these might help. Questions: ride@saddleupcycling.co.uk