Functional Threshold Power
What is FTP or Functional Threshold Power?

FTP is supposed to represent the Power you can hold for 1 hour.

There are many different tests on how you can calculate your FTP:

  1. 1 hour Test

  2. 20min Test: 95% of the power you were able to sustain in a 20min max effort

  3. 8min Test: 2x8min at max power. FTP is 10% of the average of the 8min efforts

  4. Ramp Test such as found on Zwift

Why FTP matters? Well, the question is: does FTP matter?

Zwift Ramp Test
Zwift Ramp Test
FTP is supposed to represent your one hour power. An Athletes Functional Threshold Power is, as long as this Athlete trains with Power, often used to indicate and dial in your Zones based on statistics which come from the brought public. For example 6-Zone Model below

Just like with all Thresholds, also FTP is just a number on a given day that represents a value from a given test. This number can be influenced by your fatigue, sleep, temperature, indoor/outdoor etc. etc. etc.
Also not to forget is that the number can vary from test to test. 20min to 8min and % of results.
How is FTP now defined? It depends on who you ask. The question you need to ask yourself is rather - if your FTP is, lets say. 300W, do you think you can sustain that power over an hour? For a lot of Athletes the answer is NO, which raises the questions: is FTP accurate? Another ankle to look at is that FTP is often described as a Lactate Threshold of 4mmol. But when we test Athletes they are often surprised that their 4mmol Threshold is somewhere totally different then their FTP number.
What is right and what is wrong then? How should an Athlete determine his or her Zones? The answer is, the more accurate an Athlete wants to dial in the Training Zones and therefore to train more efficient, the more information is needed. Not necessarily with a Lactate Test, but for example through a VO2Max Steptest paired with a NIRS device. With this test one would get not only Training Zones as a result but also information about the current fitness level and when tests are repeated the info if the Athlete improved and also in which areas. There are correlations between Lactate and SmO2 and also VT1/VT2 (Ventilation Thresholds)

With those Threshold we could make another indication on where those Thresholds are. With the VT1/VT2 info and the de-oxynation curve from the NIRS device we can dial in the Zones more accurately as when we would look only at the FTP number.
Maybe let us take a step back and look at the bigger picture. With the FTP we want to define our Training Zones. But the definition of a Zone is not a fixed point and gives us a range. While it is save to say that Thresholds are never at the same point, we should focus more on the Zones itself. If now the Athlete cannot sustain their FTP for one hour the questions is again, will the zones be correct? Sweet Spot training is a really efficient and good working tool to improve your fitness, but if you constantly train above that zone you are loosing a lot of that efficiency and even train total something totally different. So calculating the Zones from a wrong starting point, gives us a wrong break down for the Zones!
The most important aspect of Zones is that they are individual and that the percentages of FTP for the Zones, as described in the table above, is really only a picture of throwing all Athlete Data in one big bucket, doing a little math and based on statistic determine what the Zones for everyone should be. Unfortunately this is not how it works and those statistics break down on the individual level.
Determining your Zones from other values, such as from a VO2Max Test or other methods are therefore more accurate and will lead to a more efficient training. Why Zones from VO2Max work better? Simply because during a VO2Max test we get a very good idea of your top end number, while FTP is mostly a predicted number based on calculations and the layout of Zones comes brought public perspective.

"Continuous tests throughout the season and understanding your physiology is Important to train the most efficient way possible and get the best improvements for the time you spend exercising"

A Golden Rule to follow therefore is: Rather stay a 5-10% under then 2% over the Target-Zone to hit your workout specific goals.


FTP is really only a number, nothing else. FTP is not important at all when it comes to your own performance. There are way more important Information which really matter to look at.

So in your next conversation about FTP, think about this article, and if you still want to compare yourself by FTP against others... at least ask for the other Athlets weight and do the conversion into W/KG. :) You will also get a laugh out of it lot of times since lot of people answer always with: "well my weight, ahm, i am a little heavier then normal currently"

Functional Threshold Power

FTP just a Number or does it really matter?



Subscribe to be updated about latest news and blog posts and to follow what is happening in a magical land of Bali.