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What is FTP?

FTP stands for functional threshold power. Power (or watts) is one of the most reliable indicators of cycling performance and is an excellent way to measure training intensity. You get immediate feedback on current training zones and intensities. Completing a field test to determine your FTP has become a generally accepted way to measure an approximation of your lactate threshold power on the bike. From here, you can calculate training zones and develop racing parameters. Lab tests offer the most accurate physiological measurements, but are not always practical or available to all triathletes.

Let’s take a deeper dive on what FTP really is, why it exists, what it means for your training, how to train to improve your FTP and do you want or need to? Are there other options?

What is FTP and why is it important?

One of the best ways to understand how to train with power is to complete a test, in the field or in the lab. This determines your current level of fitness. Remember, that with any test, if you’re doing it for the first time, there can be a learning curve. How hard do you go, what can you sustain? So, it’s ok to do a field test once a week for a couple of weeks as you learn. As Hunter Allen, author of Training and Racing with a Power Meter, often says “training is testing and testing is training”. You gather information and data from every ride you do.

Lactate threshold is a common term, but still one that can bring confusion to new and experienced triathletes alike. Science has established that the point where your body begins to accumulate lactic acid in your blood faster than your body can eliminate it is called the “lactate threshold”. This physiological marker is a powerful predictor of endurance performance in events from a 3k run to an Ironman. Terminology may get confusing, but this is a physiological fact and forms the basis for the creation of the FTP protocols.

The FTP is meant to be a practical test and application of your current capabilities expressed in watts on the bike. FTP and lactate threshold are not the same thing. Lactate threshold can only be determined through blood tests in the lab. But, lactate threshold and FTP are closely related.

Hunter Allen: “FTP is the highest power that a rider can maintain in a quasi-steady state without fatiguing. Your FTP provides a solid basis for any power meter-based training program, because your level of effort when exercising at a given intensity depends upon your power output relative to your power at FTP. When you power output exceeds your FTP, you’ll fatigue quickly. When your power output is just below FTP, you’ll be able to maintain it much longer.”

There is a misconception by some athletes that the FTP is “too anaerobic” to be useful for long course triathletes. In fact, approximately 92% of energy used during the FTP test comes from aerobic energy. Anywhere from 5-10% comes from anaerobic glycolysis (fuel breakdown for fuel using anaerobic energy pathways).

Why use the FTP test and training parameters?

There are several ways to determine or calculate your FTP, but the easiest is the 20-minute FTP test protocol. The data you get is highly useable. The test consists of a good warm up, followed by a 20-minute all out time trial effort which can be done on a trainer or on the road. In fact, it’s good to do it both places depending on where you live, road and weather conditions. Retest approximately two to three times per year to check progress and make adjustments in your training parameters or zones.

Your FTP is calculated as 95% of your 20-minute TT effort. This decrease of 5% is meant to reflect what your effort might be for a full 60-minute TT effort without actually having to do the longer effort. Training zones can then be calculated from your FTP test results. All zones are based on a percentage above and below your FTP. These zones represent specific energy systems pertinent for endurance athletes. So, when you go out for an all aerobic long ride, you know what wattage range will be to keep the effort fully aerobic. Or, if you’re doing VO2 max intervals, you don’t have to rely on heart rate to know where your effort should be.

The FTP test is simple to complete (vs a 60-minute time trial) and is repeatable throughout the training year. You can do this on your own without having to go to the lab and/or have blood samples taken.

What does it mean for your training?

At its most basic premise, training with a power using individually derived zones from your individual effort makes your training most relevant to you and your needs. It makes your cycling training loads manageable. Training in these zones throughout the year makes you fitter, faster and stronger in a measurable way.

Most importantly, on race day, you’ll know what kind of effort you can sustain. Following these parameters will help you race at your best by helping to manage your intensity. Go too hard on the bike at Ironman and you’re left walking the run. Go too easy at a sprint race and your competitors will leave you in the dust.

How to train to improve your FTP? Do you want to or need to?

One goal of any training program is to increase power (or pace) at threshold. This means that you can sustain both a higher aerobic effort before building detrimental levels of lactate. And, with training, that your body is more efficient at buffering lactic acid, so you can also go hard longer.

In order to see that FTP number go higher, you need to train consistently. Initially with aerobic and moderate intensity efforts, your FTP will improve. As you get fitter and stronger over time, you will need to do harder efforts at threshold or VO2 max.

If you’re new to training with a power meter or new to triathlon in general, you definitely want to see your watts go up, especially at FTP. But, if you’re training long course and you’ve been training for many years, you may not see your FTP go up, i.e. it may hit a ceiling. Understand that just because this number doesn’t go up all the time, doesn’t mean you’re not getting fitter. There are other physiological parameters to measure that may be a better indication of your current fitness, such as CHO (carbohydrate) vs fat metabolism, VO2 Max, VLaMax (maximal lactate production rate), etc.

Shortfalls of using FTP.

The reality is that FTP testing has its limitations. For example, you are only measuring one small slice of the exercise physiology “pie”. What about short course athletes, especially those doing ITU or draft-legal racing? The speed requirements at those distances is tremendous.

A more complete picture of your capabilities and physiological gifts or shortcomings is to look at the Power Profile and/or Critical Power. These are somewhat similar concepts.

With the Power Profile (Coggan, Allen, McGregor), you take maximum test data from 5 seconds, one minute, 5 minutes and FTP. You can then look them up on the chart to determine where you measure up among men or women in your category. This will show where your current strengths are and which energy systems are the strongest. Then compare how this stacks up against your current goals as an athlete. For example if your FTP tests high on the scale, then you’re clearly an endurance athlete. But, if your 5-minute power tests highest, your strengths may lie in shorter, speed driven events. FTP is not a great predictor of sprint performance.

Critical power, using mathematical modeling, takes the results of several all-out efforts between 3 and 30 minutes, then plots the watts against time on a graph. By fitting a line across all data points, the slope of the line is called critical power. This value tends to correspond very closely with any determination of FTP.

Other ways to determine your FTP include (data taken from your power meter’s software or coaching software such as WKO or TrainingPeaks): power frequency distribution charts, routine steady power, normalized power, mean maximal power, one-hour time trial, and computer modeling.


Measuring and tracking FTP and using the 20-minute test protocol offers practical, everyday applications to make your training with a power meter robust, meaningful and successful. It is not all things to all athletes in all situations. But there is no one single test that will provide all the information you might need at any given time. There are situations to use other methods and protocols. Focused attention on methods and protocols that are robust for you are probably the best for you.

The best predictor of performance is performance itself.

References & Resources

Allen, Hunter; Coggan, Andrew; McGregor, Stephen. Training and Racing with a Power Meter. 3rd edition, 2019.
Brett, Mat. Training: All you need to know about FTP – what is it? Why is it important? How do you calculate yours? And what are its limitations as a training tool? Nov 11, 2019.
Coggan, Andrew. What is Functional Threshold Power? TrainingPeaks: Training Articles, Feb 10, 2016.
Schmitz, Roger. Comparing critical power and functional threshold power. Mar 12, 2013.
That Triathlon Show (TTS), podcast: FTP, VO2 Max and VLaMax: What triathletes need to know with Sebastian Weber. Episode #169
TTS: podcast Q&A #62.
TTS: Q& Q #20: Testing for half and full distance triathlon
Vromen, Guido; Van Bon, Marco. Should you be evaluating your cyclists using critical periods? Jan 8, 2019. TrainingPeaks Training Articles, Coach Blog.