Functional threshold power (FTP)
Functional threshold power (FTP) is the highest average power, in watts, that a cyclist can sustain for roughly an hour. It marks the boundary between efforts you can hold for a long time and efforts that tire you quickly, which makes it the anchor for power-based training zones.
How to test your FTP
The classic test is a 20-minute all-out effort after a thorough warm-up: your FTP is about 95% of your average power for those 20 minutes. A ramp test is shorter and easier to pace. Power rises every minute until you can't hold it, and your FTP is estimated at about 75% of your best one-minute power.
Both are estimates. Ramp tests can overestimate FTP for riders with a strong anaerobic kick and underestimate it for diesel-type riders, so stick with one protocol and retest every 6–8 weeks.
What a good FTP is
Raw watts favour heavier riders, so FTP is often compared as power-to-weight in watts per kilogram. Many recreational riders sit around 2–3 W/kg, strong amateurs above 4 W/kg, and professionals above 5.5 W/kg. The more useful comparison is with your own FTP from last season.
How to use FTP in training
Once you know your FTP, every interval can be written as a percentage of it: endurance rides at 56–75%, sweet spot at 88–94%, threshold at 95–105% and VO2 max intervals at 106–120%. That keeps the workouts right for your fitness rather than someone else's.
In The Next Race
The Next Race's ramp test estimates your FTP as 75% of your best minute and offers to save it. Every bike interval in its plans is written as a percentage of FTP, so the targets update when your FTP does — and ERG mode holds them on a smart trainer.