If you plan on doing any structured Zwift training, the first step is determining your functional threshold power (FTP). Your FTP is the wattage you can stay below and sustain for longer durations, while going above it causes fatigue to occur very quickly. FTP is a key metric for tracking cycling fitness, and it is also used to set power targets for workout intervals.
Set it too high and your workouts will be difficult or impossible to complete. But set it too low and your workouts won’t push you hard enough!
The best way to determine your FTP is with an FTP test, and Zwift offers three built-in methods found under Workouts>FTP Tests:
- FTP Test
- FTP Test (shorter)
- Ramp Test
All three tests involve a skill component and require some mental toughness. And any of them will give you a reasonably accurate value for your “threshold” power. So why are there three tests, and which is best for you? Read on to find out!
The first two options are essentially the same in terms of effort and results, but the shorter version reduces the warmup and cooldown time. In these tests, riders complete a warmup which includes a strong 5-minute effort to get the legs pumping. The actual test which follows is 20 minutes long, and your FTP will be automatically calculated as 95% of your average wattage during that 20-minute period.
The ramp test is completely different. It begins at a low wattage which increases steadily each minute until you aren’t able to turn the pedals any further.
Which test should you take? That depends on your experience level and what you are training for.
The ramp test is easier to do “correctly,” so if you’ve never taken an FTP test before this is the best place to start.
In contrast, the standard 20-minute test requires a high degree of mental toughness due to the longer effort, and it can be a real challenge to pace properly for best results.
Experienced cyclists training for endurance events should probably choose the 20-minute test since it more closely mimics the longer-interval training you will be doing for your events.
Alternatively, if you are an experienced rider training for shorter events such as criteriums which involve lots of short intervals, the ramp test may be best since it mimics the kind of intervals you will be training.
When properly paced, the 20-minute test is considered more accurate than the ramp test since it more closely simulates the long, steady, aerobic effort which FTP measures.
If your strength is holding high power over short time periods you may receive slightly inflated results from the ramp test, since it is based on your best 1-minute power. In contrast, the 20-minute test is based on a 20-minute average, so a strong 1-minute effort will do little to skew the results.
The ramp test only begins to hurt the legs in the final 3-5 minutes, making it the least painful option.
The 20-minute test, on the other hand, will involve 10+ minutes of significant suffering, even when properly paced.
The ramp test is as simple as it gets: just start pedaling and keep going until you can’t go anymore!
The 20-minute test’s 20-minute window can be very difficult to pace if it’s your first time (see FTP pacing tips). Even if it’s not your first time, if your FTP has changed significantly or you go too hard too early, pacing can prove a real challenge!
Suggestions for First-Timers
If you’ve never taken an FTP test, start with the ramp test since it is the simplest, least painful option. This will give you a very solid estimate of your FTP which will be automatically applied to your structured workouts.
One last suggestion: make sure you’ve got a fan, water, and towel ready before starting so you don’t have to stop in the middle.
Whatever FTP test you choose, we know you’ll give it everything you’ve got. Go get it!