FTP Testing

As a cycling coach and a Power Zone Training Instructor for Peloton, “FTP Testing” is a frequent topic of conversation as well as debate. “FTP” stands for “Functional Threshold Power” and is typically described as the power or output one could sustain for around one hour. While there are many types of “FTP Tests”, the most well-known is the 20 Min test.  Having completed many FTP tests in my life, it’s easy to understand why this is: They are hard!!

The purpose of this article is to discuss the background behind FTP Testing, revisit why we should care about measuring/estimating FTP and address some common questions I have received. But, before we dive in, it’s important understand what “Power” or, as we refer to at Peloton, “Output” is and how it is used in FTP testing.

Understanding Power

In order to improve one’s fitness, you first must measure it. FTP testing relies on one of the most accurate forms of measuring intensity available to cyclists: Power. Power is a performance-based metric measured in Watts. In physics, the definition of power is work divided by time or, plainly speaking, a rate of work. It essentially combines how fast you are pedaling with how much resistance you are pedaling against in order to calculate how many watts you are producing. Thus, power is a measure of intensity or effort. Therefore, the harder that you work, the more watts you produce and vice versa.

The FTP Test is simply a test to see how much power you can maintain for a certain amount of time. This leads us to our next topic of conversation: What is “FTP”?

What is “FTP”?

“FTP” Stands for “Functional Threshold Power” and is thus an estimate of the power one could sustain while working at threshold intensity. More specifically and according to the creators of the 20 Min FTP Test, Hunter Allen, Dr. Andrew Coggan and Dr. Stephen McGregor define FTP in the third edition of “Training and Racing with a Power Meter” as:

“…the highest power that a rider can maintain in a quasi-steady state without fatiguing. When power exceeds FTP, fatigue will occur much sooner (generally after approximately one hour in well-trained cyclists), whereas power just below FTP can be maintained considerably longer.’

While we could certainly dive deeper into the chemistry behind what “lactate” and “threshold” mean, I think it’s easy to see that at a surface level, as a cyclist’s fitness changes, so does their FTP. This is an important point because it means that your FTP responds to changes in your fitness. Thus, changes in your FTP can not only indicate changes in your fitness but can also help predict performance, specifically endurance performance.

Knowing that one’s FTP is essentially a physiological benchmark of how much power they are producing at threshold intensity gives us a starting point to estimate how hard they are working at other levels of power. Scientists can then study what is going on inside the body when working at different percentages of FTP. These percentages of FTP make up what is called an “intensity continuum” which has been broken down by coaches and exercise physiologists into the generally accepted seven zones that we know in Power Zone Training. These percentage ranges as well as their associated descriptions are provided below:

The zones provided above are the “Classic Levels” that suit the training needs of most people. Notice that 100% of FTP falls in Zone 4, this is why Zone 4 is labeled Lactate Threshold.

Measuring FTP

The truth is that there are many ways to estimate one’s FTP. The most accurate method is generally considered to be testing in a lab. The problem with this is that it is inconvenient and typically expensive. The other reality is that the data has proven the efficacy of lab testing is not much better than the less expensive field tests like our good friend, the FTP Test.

No matter the test however, none are perfect in that they all have advantages and disadvantages. For example, those who are more aerobically gifted will do better with the longer tests whereas those more anaerobically gifted will do better with the shorter tests. Another disadvantage of most field tests is that even though it might not involve riding all-out for an hour, it is still hard. Most of the well-known tests however will likely get you in the range of +/- 5% of what you find in a lab.

Below is a brief list of some of the existing options to estimate ones FTP:

  • Riding all out for an hour (i.e. a one-hour time trial)
  • 20 min Test
  • 30 min Test
  • 8 min Test
  • 5 min Test
  • Reviewing power frequency distribution charts and/or normalized power data from your training and/or racing
  • Ramp Test
  • Estimating based on feel
  • Mathematical modeling
  • Computer modeling

While I am not positive that I listed all the possibilities, I am nearly positive that I know what works: Picking one and sticking to it! I say this because if you are constantly changing testing methods, it’s hard to know whether the change is due a change in fitness or simply a change in testing. Isolate the variables and stick to one. The gold standard is the 20 Min FTP test developed by Hunter Allen. I believe this is a good one (at least to start with) for primarily the same reason he does, because “the best predictor of performance is performance itself.”

What is the 20 Min FTP Test?

The goal of the 20 min FTP Test is to record your highest average power for 20 min. An important part to this test (as well as any) is following the same warm-up protocol. While at Peloton we have structured 10-15 min warm-ups designed for this test, Hunter Allen’s warm-up is 46 min and some are longer! In general, the trend I have seen is the more experienced the athlete, the longer the warm-up. Again, what’s important is that you stick to a protocol that works for you before starting that 20 min effort.

During the 20 min effort, a common question I get is, “What’s the best way to attack the 20 min effort?” In general, the answer is avoid going out too hard too soon and having to stop early. To help people avoid this, I coach them to start on the lower end of where they think their FTP is and build from there. For example, if you think you could average around 180-200 Watts for an hour (i.e. your estimated FTP), start around 180 Watts as you will feel more confident that you are not going out too hard as the test is only 20 minutes.

Since the goal of the test is to record the highest average power possible, you don’t want to stay at the same power you started at. So, I like to break the test down into 4 x 5 min quarters with the goal of raising power a little each quarter. Of course, this is tough because you start to walk a fine line between pushing so hard that you want to stop and not pushing hard enough. That said, it’s a great way to get those new to FTP testing through it with less risk of having to stop early. As you get more experienced with the test, you will get better and better at executing it and probably less reliant on the four-quarter approach. In terms of cadence, I coach the athletes to not worry about a specific cadence but instead stick to whatever feels best in the moment and stay in the saddle as much as possible.

Once you have completed your 20 min FTP Test, you have to remember that “FTP” is the power you could sustain for around an hour. Having only cycled for 20 min, you have to decrease your 20 min average power by around 5% in order to arrive at an estimate of your FTP. 

Where should you test?

Choosing where you test is very important, and the answer is: test where you plan to train. If you are primarily training indoors, test indoors. If you are primarily training outdoors, test outdoors. If you are training both indoors and outdoors, I would test both because there will be a difference with outdoors generally being higher than indoors.

For those of you testing outdoors, be careful! Try to select a course with little to no street crossings and a gently upward sloping terrain. As someone who lives in NYC, we used to test at 5:30am in Central Park in order to limit the risk of running into anyone else on the roads.

When should you test?

In general, you want to test when you are feeling good and ready for a challenge. Avoid testing tired or fatigued. In terms of timing of when to test within a consistent training schedule, it’s generally best to test at least a few days into a recovery week. This way you have had a chance to shed some residual fatigue from the previous week(s) buildup in training load.

How often should you test?

If you are new to Power Zone Training, coming back from time off, and/or are committing to consistent training schedule it’s a good idea to test more often vs less. The following is a brief list of reasons why testing more often in these cases is recommended:

  • You want to do this so that you are sure your training levels (based on your FTP) are appropriate for you. For example, if your training levels are too easy, you will not be progressing as quickly as you could. On the flipside, if your training levels are too hard, you could be overstressing your body and risking injury or burnout.
  • Testing more often helps you get comfortable with testing and helps reduce anxiety around “testing”. I tell my athletes to look at them as hard workouts vs some big event. Testing not only gives you an idea of where your FTP is but also teaches you how to prepare to perform. This is a very important lesson, especially if you plan on racing.
  • During your first few tests, part of your improvement will simply be learning how to test. A good analogy is multiple choice exams in school: With a little practice on strategy, you can improve your results. Eventually however, you will start to get a good read on where your body is at.
  • When you are a beginner or are coming back into consistent training after time away from the bike, your body adapts to the training in much the same way. The best way to visualize what to expect as your training progresses is graphically. Below are two graphs that help represent how your body adapts to training over time. Graph #1 is the “30,000 ft view” whereas Graph #2 is more granular and shows the performance peaks and valleys that we all experience along the way.

Graph #1

Source: “Practical Programming for Strength Training” by Mark Rippetoe and Andy Baker

Graph #1 – Illustrates the relationship between performance improvement, rate of adaptation and training complexity over time. Notice how rate of adaption and performance improvements are significant at first. In order to ensure your FTP represents your current fitness level during this time, you need to test often because your fitness is changing often. As your training progresses, FTP improvements will become harder and harder to achieve. This is where training complexity needs to increase and is thus a good time to sit down with a coach and/or get more strategic with planning out use of the training variables: frequency, intensity and duration. For tips on this, please check out my post on the topic located here.

Graph #2

Source: https://www.trainingpeaks.com/blog/trainingpeaks-success-story-how-michelle-achieved-cat-3-success-by-season-planning-with-tss/

Graph #2 – Shows how fitness (or “CTL” illustrated in grey) has peaks and troughs from year to year and season to season with the athlete’s focus on improving from peak to peak. Notice how peak performances follow significant decreases in performances. This goes to show that not only is the idea of consistently maintaining peak fitness level not realistic but also the importance of analyzing one’s approach to achieving peak fitness each season. For example, in the final peak, this athlete clearly ramped up their training much quicker and for longer than in the past…and it worked!

When it comes to planning out your testing schedule, you can follow a structured or unstructured approach. A structured approach towards testing could be every 3-4 weeks at first. Then, as you gain more fitness and experience you could shift it to every 4-6 weeks or even every 6-8 weeks. Following a consistent testing schedule makes sense for when you are training towards a goal or event because it can serve as a way to not only keep your training levels/zones updated but can also be used to set goals and targets. For example, “My target on my next FTP test is to average XYZ Watts and achieve a 10% improvement from my previous test.”

A less structured approach towards more frequent testing is where you and/or your coach look for signs in your workouts that it’s time to retest. For example, your zones are starting to feel too easy or you start blowing away your testing averages in workouts on accident. These are great signs that it is time to retest and I recommend that you do so because FTP tests are designed to not only help you maximize your average output, but they also offer a standardized approach towards assessing your fitness.

Lastly, testing is often beneficial when your goal is to improve. When your goal is to maintain or just exercise, testing often may not be necessary. Many non-competitive athletes find this approach most enjoyable and throw in tests whenever they feel like it and/or when they feel like their training levels are off (harder or easier). This is certainly okay but know that this approach comes at the cost of slower progress.

Common mistakes and misunderstandings:

Below is a list of some of the common mistakes and misunderstandings that I have seen during my time coaching:

  • Using your 20 min average power to calculate power zones – Remember to use the 20 min avg power minus 5% of your FTP. Remember that FTP is an estimate of your one-hour power. Therefore, using an average power number of anything less than one hour needs to be discounted.
  • Expecting that your FTP is going to go up infinitely – Per Graph #1 above, we are all limited by our genetic potential. As we get closer and closer to that potential, the rate of adaptation decreases and thus our performance gains start to get smaller and smaller. Furthermore, don’t expect your FTP to be at its max all the time. Athletes have seasons for a reason. In-season they are working on specific fitness towards achieving specific goals (in most cases, performing better than they did the previous season). Off season they are focusing more on general fitness and relaxing a little. This is a healthy way of looking at your training. Lastly, remember that even during “in-season” training, there are peaks and troughs along the way, so patience is very important.
  • Hitting structurally hard workouts with new zones – If your zones/levels go up after testing, remember that this means you will be expected to hold higher power in future workouts than you did in the past. This alone can make structurally hard workouts feel impossible. Focus first on building comfort with the lower zones after retesting before blasting yourself with long intervals at higher zones.
  • Guessing one’s FTP based on perceived effort in order to set zones/levels – While this is likely the least accurate way of estimating your FTP, it makes sense in certain situations, for example if you are pregnant or if you are coming back from injury or sickness and your body isn’t ready for an FTP test. In the cases where this makes sense, the athlete is usually more focused on exercising just to exercise vs monitoring their progress. That said, getting into a habit of guessing vs testing beyond the reasons just described can result in a false sense of reality. This is why I tell all my athletes that if they think their zones are higher, they must earn them by proving it in testing.
  • Going too hard too soon – Coming back from injury or time off, it’s important to take it easy at first. In general, the longer the time you have had spent away from the bike, the longer the time you should take it easy when building back up. Just focus on pedaling easy at first and don’t test until your body is ready and you have cleared it with your doctor.
  • Having a higher FTP than someone means that you are faster than them – Not necessarily. You need to look more at what’s called “Power to Weight Ratio” in order to have a better idea of where you stack up. The formula is simple: FTP divided by body weight. There are many charts out there that will show you how your ratio compares. Fair warning: these charts assume that you tested on an accurate power meter. Since many power meters are not calibrated properly, this means your results can be skewed in either direction.
  • Confusing Power Zones with Heart Rate Zones – Workouts are designed to use either heart rate or power to guide intensity, never both. If you are taking a “Heart Rate Zone Class”, focus on heart rate during the workout, not power. If you are taking a “Power Zone Ride”, focus on power during the workout, not heart rate.
  • Focusing more on Heart Rate than Power during a Power Zone Workout – In general it is usually not beneficial to focus on heart rate during a power zone workout. An exception, of course, is if you have a heart condition and need to keep your heart rate below a certain BPM. I coach athletes not to look at heart rate data during power zone rides for four reasons.
    1. Heart rate date is more variable in nature than power. For example, maybe you had a strong espresso before you hopped on the bike. This alone could spike your heart rate.
    2. Focusing heavily on heart rate can be a self-fulfilling prophecy. For example, simply worrying about your heart rate can cause you to breathe heavier, which can make your heart rate go up.
    3. For longer efforts you will likely see cardiac drift occur which is where power stays the same, yet your heart rate drifts up.Instead, looking at heart rate data after power zone workouts can be very insightful as you can see general trends in how your body is handling your zones.
    4. Looking at heart rate data after power zone workouts can be very insightful as you can see general trends in how your body is handling your zones.
  • Expecting FTP Improvements while focusing on improvements in another sport – Running is great example here. Many runners include cycling as part of cross-training however they forget that there are both central and peripheral aspects to performance. The same central (for example cardiovascular) improvements can happen from both forms of exercise however the peripheral (for example musculoskeletal) improvements are very specific to the sport. Thus, my advice to runners is to focus on achieving improvements in running and keep their cycling light and aerobic.
  • I’m too old to train like this – Ha! Studies have shown that most of what we consider “aging” is due to our lifestyle choices. I firmly believe in not training less as we age but instead changing how we train to better accommodate changes in physiology. A good example is taking more time to warm-up as well as stretch. Furthermore, we can improve our fitness at any age. If your goal is to improve, FTP testing can help.
  • Assuming your cycling FTP is the same as your running FTP – While running with power is still pretty new, running FTP’s and cycling FTP’s are typically different because they involve different muscles, biomechanics, and measuring devices. Therefore, it’s best to test them separately.
  • FTP is the only metric that matters – Genetics can make you more gifted aerobically or anaerobically. More simply, you can be more gifted at endurance efforts vs sprints and vice versa. You can also train your body to improve aerobically or anaerobically. FTP is a measure of your ability to ride hard for a long time, thus it’s highly aerobic in nature. That’s why there are three other metrics of interest: VO2 Max, Anaerobic Capacity, and Neuromuscular Power. While there are other tests for these, all four together make up what is called your “Power Profile.”

Closing Remarks

As you can see, it makes sense that FTP Testing is a frequent topic of conversation and debate in cycling. While the field tests can be challenging, there is tremendous value in estimating one’s FTP. From helping us train smarter to helping us predict race performances, FTP is one of the best measures we have available to pretty much everyone.

Just like most things however, there are always exceptions, and nothing is perfect. That’s why I hope this article will help better explain what FTP testing is and how you can use it make more informed decisions about your training in the future!

Train hard, train smart and always have fun!!


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