If you’ve ridden with enough veteran cyclists or have ever worked with a coach, you might have come across the term functional threshold power or FTP. While it sounds a little intimidating and even more confusing, it is a smart way to inform your training and to make the most of your rides so you can improve performance.

Here’s what you need to know to incorporate it into your riding life.

What is FTP cycling?

Simply put, FTP is the average number of watts that a rider can sustain in an hour, and acts as a current measure of fitness. Ideally, it refers to a steady effort, not the up-and-down levels you might see looking at your power during a hilly ride or cyclocross race or of course, a HIIT workout.

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FTP, which is typically calculated by a 20-minute test, is useful because “it’s a number that you can track, so you can see improvements as you test regularly,” explains Jane Marshall, a CTS cycling coach in Littleton, Colorado. “A lot of the time, we ride and think we’re getting faster, but FTP is one way to know for sure if we’re getting faster, versus just thinking it’s because of a group ride that went well or a good day on the hills.”

Plus, you’ll need to know this number if a coach prescribes training zones with power.

While FTP can be helpful, Marshall says, it’s also “one of the most misunderstood things in cycling.”

How do you measure FTP?

First, you need a power meter. Then, you need a place where you can ride for at least 20 minutes straight. Optimally, you would do the FTP test in a one-hour time trial, but that isn’t realistic for most riders. Instead, the standard procedure (and the option that works well for your first FTP test) is the following:

  • Calibrate your power meter
  • Warm up for 10 to 15 minutes
  • Ride at an all-out effort for 5 minutes
  • Follow that by 10 minutes of easy spinning
  • Finally, ride at an all-out effort for 20 minutes, aiming for a pace that’s your hardest consistent effort—it should remain steady and not undulate (for easier calculation, make sure you press the lap button before you start your 20-minute effort)
  • After, ride easy for about 10 minutes to cool down

Then, take the average power of that 20-minute effort and multiply it by 0.95 to get your FTP. For example, if you average 200 watts, your FTP will be 190 watts.

Once you’ve got your FTP and feel comfortable taking the test, you can graduate to a more advanced FTP test method. This one is recommended by Bicycling’s coach David Lipscomb.

You can gauge your effort by your rate of perceived exertion (RPE), a 1–10 scale with 1 being an effortless spin and 10 being an all-out sprint or use your previous FTP results. Cool down post-test with 10 to 20 minutes of easy pedaling followed by five minutes of your favorite lower-body stretches. To ace it, get Coach David’s tips for taking this test here.

Start with a three-part, 20-minute warm-up:

  • 0:00–07:00: Easy spin, slowly increasing effort (RPE 2 to 4)
  • 7:01–14:00: Steadily ramp up to RPE of 8 out of 10 (or 115% of your last FTP) and hold that 8 RPE effort for one minute.
  • 14:01–20:00: Recovery spin (RPE 2 to 3), hydrate

Follow immediately with a three-part FTP test:

  • 0:00–2:00: Start at an RPE of 7 to 8 (or 110% of your last FTP)
  • 2:01–10:00: Settle into your pace and hold it there
  • 10:01–10:30: At this midpoint, take 15 to 30 seconds to drop to around 60rpm while increasing resistance to maintain your power. This will lower your heart rate and provide a mental break
  • 10:31–17:00: Bring your rpms back up and cruise at 7 RPE—this section is the hardest and will push your mental toughness; focus on maintaining your cadence, while staying relaxed
  • 17:01–20:00: Empty the tank and aim for 8 to 9 RPE or about 15 to 30 watts higher than you’ve been averaging (or 106 to 109% of your last FTP); finish strong!

It doesn’t matter if you test inside or outdoors. Just make sure you ride in repeatable conditions, says FasCat Coaching founder Frank Overton. If you test outside, aim for a gentle hill with a 20-minute or longer climb, or at least a stretch of road that won’t involve frequent stops or steep downhills.

Can an FTP test improve performance?

Absolutely, for two reasons: First, testing every few weeks gives you a great indicator as to whether your training plan is working how it is intended. Second, it pushes you to do a relatively hard workout regularly, which can be great for someone who hates intervals and tends to skip out on high-intensity work.

How should I use FTP results in my training?

Coaches will often use FTP when programming workouts in order to get more specific about interval sets. In fact, it’s Overton’s primary reason for wanting his athletes to test, as FTP doesn’t just give you a threshold number; it helps create “power zones,” similar to heart rate zones like recovery, endurance, tempo, VO2, and sprint, which can be used to hone your training.

More importantly, regular testing can show progress, or lack thereof. So while it isn’t a training tool by itself, analyzing FTP test results does reveal if your training is working for you—or if you need to change something to see better results.

A steady increase is ideal, but don’t expect big leaps. Simon Marshall, author of The Brave Athlete, says a 2.5 percent increase in FTP in a training cycle (about six to eight weeks) is a good power increase. Anything more is unsustainable. If you see your FTP decline or stay stagnant for more than two tests in a row, it’s time to consult with your coach or adjust your training.

How do I know if my FTP is good?

To get a sense of how your FTP in cycling stacks up, Overton recommends converting it to a power-to-weight ratio—your FTP divided by your weight in kilograms. (A 150-pound rider with a threshold of 200 would have a power-to-weight ratio of 2.9.)

Overton says the average newer rider with some fitness will hover in the 2.0 range, while top cyclists in the world hover around 7.0. That number won’t affect your training at all, but it’s a good way to see how you compare to other riders.

What if my FTP sucks?

Don’t stress about it. These numbers don’t exist in a vacuum. Your FTP will fluctuate depending on your season of training and current health status, plus any number of external factors during testing. A harsh headwind, extreme heat or cold, or even just a stressful week at work could all have an effect.

While having a good FTP test is ideal, just remember: You might be in a phase of training where your endurance is improving for longer, easier efforts, or your high-end power for quick bursts is on the rise.

So rather than fixate on one bad test, keep training steadily, and you should see that number rise over time.

How often should I do an FTP test?

If you get a number you’re not happy with, it’s tempting to repeat the test as soon as possible. Resist that urge. Testing monthly is perfectly fine, and since it’s an all-out effort, you don’t want to do it too often.