Functional Threshold Power (FTP) – What, Why and How


What is FTP?

Functional Threshold Power (FTP) was developed by Dr. Andrew Coggan and is specifically defined as “the highest power a rider can maintain in a quasi-steady state without fatiguing. It is an estimate of the power output that corresponds most closely with the maximal metabolic steady state or metabolic control limit, or what is more commonly referred to as threshold.” (See Training and Racing with a Power Meterby Andrew Coggan.)

In the last several years, many other authors and publications in the media have taken their views on what FTP means, resulting in various definitions. More and more phisiology experts, coaches and athletes are opting for other methods of determining their threshold and training zones, as FTP has many limitations.

Why is my FTP important?

FTP is perhaps the most popular training tool because it is relatively simple to determine by any athlete on their own. If you want to train with purpose, get fitter and faster on the bike overtime, you will need to know your FTP or a similar measurement of your level of fitness to determine your training zones. Your coach will be able to design your workouts by using power zones as a percentage of your FTP.

How do I measure FTP and how often should I test?

There are several ways to measure FTP through riding, indoors or outdoors. These are typically referred to as “FTP tests”.

The most popular and commonly used test is the 20-minute time trial, with the goal of producing the highest average power possible over this period. The FTP will be 95% of the average power produced over the 20-minute period. For example, if your average power for the 20 minute effort was 100 watts, your FTP is 95 watts (100w x 95%).  Why 95%? Because experience shows if you can ride at 100w for 20 minutes, you should be able to ride for 95w for 60 minutes.

By contrast, Dr. Stephen Seiler, one of the most respected physiologists, says that a 60-minute time trial is the most accurate way to determine an athlete’s threshold.

There are other ways to measure your FTP, and the science of performance is quickly evolving. Take a listen to this podcast on the reasons why FTP might not be the “end all, be all” measurement for training.

The frequency of testing should be coordinated with your coach. In the early stages of development, testing every three months is quite satisfying because improvements can be quite large. Over time, and if you are a more seasoned athlete, FTP growth will slow making the test frustrating at times. However, I personally test every three months.

Are there any tricks or tips for performing the FTP test?

Watch this short video I prepared showing a few approaches you can use for the 20-minute FTP test.

Dr. Coggan recommends performing the test on a road that is fairly flat, allowing a strong, steady effort for the entire duration of the test. Starting hard will only get you tired and your power will start to fade.

It’s better to start conservatively for the first two minutes, build speed, then start increasing the effort as you gauge how your legs feel. The test can also be performed indoors on a trainer and even on Zwift (see below).

Another option is to measure your power during a race to determine your FTP. The motivation from the race alone can make a difference, and riders tend to go harder when competing! You would need a power meter for an outdoor test.

FTP Tests on Zwift

You can perform an FTP test on Zwift by selecting any of the two available workouts, described below. Upon saving your ride, you will be notified of your FTP.

FTP Test – Standard

The standard test on Zwift starts with a 20-minute ramp that goes from 30% to 70% of FTP. Next is 3 sets of 3 intervals, each for 20 seconds at 90%, 110%, and 130% of FTP (9 minutes total), followed by 5 minutes at 60%, 5 minutes at 110% and 10 minutes at 60% of FTP. Then the test starts: 20 minute block where you ride as hard as you can sustain for that duration. Cool down for 10 minutes.

FTP Test – Short

This version of the test has a shorter warm up. It starts with a 5-minute ramp going from 30% to 70% of FTP. The next set is 3 intervals of 20 seconds each at 90%, 110%, and 130% of FTP, followed by 3 minutes at 60%, 3 minutes at 110%, 2 minutes at 120%, and 6 minutes at 55% of FTP. Then the test starts: 20 minute block where you ride as hard as you can sustain for that duration. Cool down for 5 minutes.

FTP Standard (short) test on Zwift
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Theia is a licensed professional USA Cycling Level 3 coach with Vision Quest, and coaches athletes from all over the country. A life-long lover of all forms of exercise and dance, she became a certified ballet instructor shortly before entering law school, and discovered her passion for cycling when she got her first road bike from her husband Drew on their wedding anniversary. Theia is also an active member of the cycling community in Zwift, and leads a ladies’ race series for Team ODZ and weekly workouts for Zwift Academy. In addition to coaching, Theia can be found enjoying daily rides and participating in races, long endurance events, and cycling camps.