How to Properly Conduct a Functional Threshold Power (FTP) Test - Coach Tip Tuesday

Power-Based Training.  It’s all the rage, especially since indoor cycling training platforms have surged in popularity over the last several years.  Power is the metric that popular platforms such as Zwift, TrainerRoad, Rouvy, and FulGaz leverage to have riders utilize their software, and the ability to measure power is available on many new indoor cycling trainers.  Additionally, since power meters themselves have become more cost-effective in the last 8-10 years, more and more athletes are interested in purchasing them and using them for their outdoor training as well as their indoor training.

As I’ve discussed in the past, power is a great and wonderful tool for athletes to leverage when they are riding.  It does provide the most accurate measure of exactly how much work a rider was doing in a workout or ride.  When interacted with frequently and consistently throughout all cycling training, power can be a very meaningful way for athletes to ensure that they’re imposing a stimulus that is appropriate for them to make adaptations and see gains in performance over time.

What is Functional Threshold Power (FTP)?

In order to train by power in cycling, athletes need to establish their Functional Threshold Power, more commonly known as “FTP”.  Without establishing an accurate FTP, athletes cannot train by power.  Period.  Some athletes try to get around this by guessing their FTP or by using the algorithmically generated numbers provided by training devices and software.  As you’ll see, this is a flawed way to approach power-based training; it sets up an athlete’s training so that it is not imposing the proper stimulus, which can lead to a lack of adaptation (read: a lack of gains or progress) or even worse, an injury.

The term “threshold” is honestly a confusing one for many athletes, as there are so many different definitions of what “threshold” means in terms of athletic training and performance.  There are also a lot of different words (Lactate Threshold (LT), Anaerobic Threshold (AT), and Maximal Lactate Steady State (MLSS), among others) for essentially the same concept.

Exercise physiologists have known for decades that every athlete has an exercise intensity where lactate begins to accumulate in the blood.  Lactate is a bi-product constantly produced in the body during normal metabolism and exercise.  Lactate does not increase in concentration in the blood until the rate at which the body is producing it exceeds the rate at which the body is removing it from the blood.  This point where lactate begins to accumulate in the blood is called Lactate Threshold, and it is a very powerful predictor of endurance athletic performance because it is an indirect marker of biochemical events (such as fatigue) happening within a muscle.

As outlined by Hunter Allen, Dr. Andrew Coggan, and Dr. Stephen McGregor in Training and Racing with a Power Meter: Third Edition, Functional Threshold Power (FTP) is “the highest power that a rider can maintain in a quasi-steady state without fatiguing for approximately one hour.”  FTP is a numerical representation of an athlete’s approximate Lactate Threshold.  When a rider’s power exceeds their FTP, fatigue will occur much sooner.  When a rider rides below their FTP, fatigue does not occur as quickly and they are able to maintain their effort for longer.  

FTP is a highly individualized metric; each athlete’s FTP is going to be different based on a variety of things, to include genetics, chronological age, training age, experience, and more.  It's important to note that you shouldn't go into an FTP Test trying to cultivate or target a specific number or result (aka you shouldn't be seeking to get a specific FTP).   An FTP Test is about establishing this tool; it is not a goal in and of itself.  

Once an athlete’s FTP is determined, training can be planned precisely because we know exactly when the athlete will start to fatigue, and therefore we know how much stimulus is too much or too little for a given athlete.  As such, power-based workouts are planned based on percentages of an athlete’s FTP and they are all designed to impose a specific stimulus and - collectively - to yield specific adaptations for that athlete over time.  This - its application in properly individualizing the training of an athlete - is why FTP is so important.

How to Determine Functional Threshold Power (FTP)

Since FTP is a measure of the highest effort an athlete can sustain for an hour, the best way to determine FTP would be to have athletes ride for an hour at this effort while recording their power data.  That being said, as most riders will agree, riding for a full 60 minutes at your highest sustained effort is an intimidating proposition.  Additionally, the truth of the matter is that most athletes (and especially age-group athletes) would have trouble correctly executing a one-hour effort like this, as it is very challenging for athletes to self-determine what hard effort they can sustain at the same output for a full hour.  Most athletes will inevitably start off too hard and fade.  In order to glean accurate data from this assessment, it is important that the athlete sustain that same high effort for the duration of the testing interval.

As a result, other methods of determining FTP have sprouted up over the years.  While all FTP testing protocols are challenging, there are some that are less intimidating and therefore are tolerated better by athletes.  The most common of these is a variation where, after a proper warm-up, the athlete rides at the hardest effort they can sustain for 20 minutes.  Then, they cool-down.  Using the data from that 20-minute interval, both Power Training Zones and Heart Rate Training Zones can be determined.

To determine FTP from the 20-Minute Test, we take the average power from that 20-minute interval.  Then, we multiply it by 95% (a factor of 0.95), and the result of that equation is the athlete’s FTP.  (So, for instance, an athlete whose average power is 150 watts for the 20-minute interval has an FTP of 143 watts because 150 x 0.95 = 142.5.  (We round up or down if the equation’s result is a fraction.))  It has been shown in numerous case studies over the years that a properly executed effort in the 20-Minute Test is about 95% of the effort that the athlete would be able to sustain if they rode for the full 60 minutes.

Once that FTP is determined, an athlete’s individualized Power Training Zones are set.  There are many different formulas available to calculate Power Training Zones; I personally use Dr. Coggan’s formula, which is:

• Zone 1 - Active Recovery - <55% FTP
• Zone 2 - Endurance - 56-75% FTP
• Zone 3 - Tempo - 76-90% FTP
• Zone 4 - Threshold - 91-105% FTP
• Zone 5 - VO₂ Max - 106-120% FTP
• Zone 6 - Anaerobic Capacity - 121-150% FTP
• Zone 7 - Neuromuscular Power - >150% FTP

While an FTP Test can be conducted either indoors or outdoors, I’ve found that conducting it indoors on a bicycle trainer is the best option since this generates consistent testing conditions year-round in all locations.  Controlled, consistent testing conditions are important in gleaning accurate data that can be compared against other data points over time.  If conducting the test outdoors, it should be conducted on a flat, open stretch of road that is rideable in all seasons without anything (such as stop lights or stop signs) that will interfere with the athlete’s ability to ride uninterrupted for 20 minutes.  If conducting the test indoors, it should be conducted on Resistance Mode on a smart trainer (not Erg Mode) or on a fluid or magnetic (aka “dumb”) bike trainer with the tension set at the same point.

Over time, this test is repeated.  Assuming that the athlete trains consistently and follows the prescribed workouts (meaning that the athlete trains by power for 95% or more of their workouts), FTP Tests should be repeated every 6-10 weeks.  (How often FTP Tests are scheduled will depend on the athlete’s training and how they’re adapting to the workouts they are doing.)  For the best and most consistent results over time, they should be scheduled following a recovery week in the athlete’s training plan.  Re-testing at this frequency ensures that the stimulus being imposed in training is always appropriate for an athlete’s current abilities.

The Important Elements of the Functional Threshold Power Test (FTP Test)

It’s important to note that every time I’ve talked about executing an FTP Test, I’ve referred to the athlete needing to execute the hardest effort that they can sustain for the duration of the testing interval.  Effort.  Effort, aka how you feel.  Effort isn’t a tangible number or metric that will be provided by any fitness device that you can latch onto.  Some of the most meaningful measures of athletic performance are challenging - if not impossible - to measure tangibly.  Effort is one such example of this.  So during an FTP Test, it is incredibly important that an athlete execute the workout/test on effort,  and effort alone.  If you cannot trust yourself not to look at the numbers that are being recorded, cover all sources of numbers/data and only look at the data after the FTP Test is concluded.

There are several important directions that must be followed in order to glean accurate results from an FTP Test.

• If you are unwilling to train by power in your cycling workouts consistently (aka follow power-based targets in almost all (95%+) of your workouts), then do not put yourself through the process of doing an FTP Test.  There is no point to incurring the mental and/or physical cost of an FTP Test if you’re not actually going to be truly training by power.
• I typically have a philosophy of “something is better than nothing”, but fitness assessments (to include FTP Tests) are one of the only times when everything must go as planned and prescribed.  If you complete the FTP Test but don't do it as specified, then you will need to redo it, and due to the high physiological impact of the test, you will need to wait at least three (3) weeks to redo it.  Much to the dismay of many athletes, it’s as simple and as hard as that.
• If you are sick or feel like you are getting sick on the day that an FTP Test is scheduled, do not do the FTP Test.  Choose something else to do that day instead or (ideally) rest.
• An FTP Test must be preceded by a rest day to be most effective, and if it's completed on a day when there's another workout, the FTP Test should be the first workout of the day.
• The data must be recorded. Getting accurate data is the only reason for doing an FTP Test.  Remember, the data gleaned from this test is going to be used to plan all of your cycling workouts moving forward.  Thus, if you cannot link your devices, do not do the FTP Test.

• Make sure your power meter is zeroed out (Garmin calls this “calibration”) and is actively connected to your fitness device before you begin the FTP Test.
• Make sure your heart rate monitor is being worn correctly and is actively connected to your fitness device before you begin the FTP Test.

• Record your nude weight before you begin the workout.

• This enables you to track your power-to-weight ratio which, even more than FTP, is a more accurate indicator of your fitness and power over time.

‍What is Being Tested

Over the years, I have seen fitness assessments, and especially FTP Tests, cause an extraordinary amount of stress and anxiety for athletes.  Athletes have reported impaired sleep, upset stomachs, an inability to eat, higher heart rates, and higher levels of anxiety for not only the days leading into the day of the FTP Test, but during and after the test itself.  FTP Tests have caused such high levels of stress and anxiety for people that multiple athletes who I’ve coached over the years have either called off of work or taken time off of work on the day of the FTP Test because the thought of the test was so consuming for them.

There are many reasons why this is so consuming and why this causes so much stress and anxiety for some athletes, but one of the main ones is the use of the term “test” in the protocol for determining FTP.  As a result, I’ve actually moved away from labeling this as a “test” in athlete training plans (I now call it a “checkpoint”), but the hard reality is that it is still a testing protocol, and altering what I call it doesn’t change that truth.  If anything, it masks it.

The actual issue isn’t actually so much the use of the word “test,” but what athletes perceive that the word “test” means about them when it comes to this workout/protocol.  Athletes see the word “test” and think that they personally are being tested (which is actually synonymous with “judged” in this instance) based on the result that is produced. Whether consciously or unconsciously, they think that the result of the FTP Test is a statement about and a reflection of their humanity, their self-worth, who they are as a person, and how they stack up against other people.  I am here to say - simply, yet firmly - that this is 100% inaccurate.

What is true is that we are seeking to establish an accurate accounting of the athlete’s abilities.  These abilities are not inherently “good” or “bad” or “pass” or “fail.”  They just are.  Yes, they may be more or less than a different athlete.  Yes, these abilities may be more or less than where an athlete has previously been.  But that doesn’t make them (either the athlete’s abilities or the athlete themselves) “good” or “bad,” and it certainly doesn’t mean that the athlete is any better or worse of a human.

Understanding an athlete’s current ability is important because accurately understanding an athlete’s current ability allows us to establish the best training and pathway to get them to their desired goals and results over time.  We need to first understand where we are so we know where are relative to where we want to go.  Then, we need to train where we are so we can get to where we want to go.  

Truthfully, all training is testing.  This is because all training - each individual workout - is an assessment of where we currently are relative to where we started, where we currently are relative to our goals, and of how effective our current skills, strategies, and tactics are.  It is only when we can accurately assess where we really are skill-wise and ability-wise that we can establish the most effective training as we move through a macrocycle or an annual training plan. 

All of this being said, there are many things that an FTP Test is actually testing, and all of them have a valuable place and use in an athlete’s training.  An FTP Test is testing:

• The highest effort an athlete can sustain, and the power number that currently corresponds with that effort
• How effective the previous training block has been for the athlete and what changes might be prudent to make in the next training block
• The athlete’s ability to pace themselves (i.e. Can the athlete accurately self-assess where they can and should start off effort-wise and maintain that effort over the course over the interval?)
• The athlete’s ability to execute a physically and mentally difficult and demanding workout
• The athlete’s ability to manage stress
• The athlete’s ability to follow a protocol (aka the athlete’s ability to read directions)
• The athlete’s ability to utilize (and appropriately ignore/discard) multiple tools in their Athlete's Toolbox

While what an athlete does in an FTP Test is not the exact specificity of what they would do in a race, there is a tremendous amount about an athlete that can be learned from an FTP Test and implemented in their training to make them smarter, stronger, and faster.  For this reason, fitness assessments, including FTP Tests, are included in athlete training plans.

The Bottom Line

Properly conducting an FTP Test is much more complex than it may appear at face value.  That being said, properly conducting an FTP Test is a skill, and therefore like so many things, it is something that athletes can get better at over time.  For athletes wanting to train by power, FTP Testing is an essential component of their training.  Simply put, an athlete cannot train by power if they are unwilling to establish their FTP via testing.

Learning how to properly execute an FTP Test and to approach it mentally in a healthy way is a valuable skill for any athlete who wants to train by power and see performance gains over time.  Doing so can really help athletes see what a powerful tool it is (pun intended).  If you currently train with power or desire to train with power in your cycling, take the time to learn this skill so you can add another tool to your Athlete’s Toolbox and help unlock your potential.