• Boris Clark

FTP misconceptions and problems (and their solutions)

Threshold power has long been coined the most important attribute in endurance cycling performance, but what is it, and why does it exist?


As we wrote in a previous post, FTP (functional threshold power) can be defined in simple terms as the best quassi steady state power an individual can hold for an approximately one hour time trial.


Quite simple, but why does it exist? Why is your FTP only 250 watts, and Chris Froomes is over 400 watts? Why is there this level that we can’t seem to go harder than for an extended time. There is of course a physiological reason for this, but you wouldn’t believe the amount of coaches who will try to sell you a plan to “increase your FTP by XYZ% in XYZ weeks” without actually understanding what FTP is, and what it isn’t.


What FTP is


From a physiological standpoint, what we are trying to define with FTP is the 2nd lactate threshold, also referred to as the anaerobic threshold. This is the point where the output of anaerobic glycolysis (pyruvate/lactate) is being produced at the same rate as it is being combusted by aerobic metabolism for energy.

FTP is therefore a combination of two main parts of physiology. The lactate production rate (VLaMax), and the lactate clearance rate (VO2Max). These two factors explain almost 100% of why your FTP is where it is, with the other factors being efficiency and economy related, ability to shuttle lactate, buffering capacities and the like.


What FTP isn’t

FTP is not a number which training zones can be based off of! This may be the power an athlete can hold for an extended period of time, but even if two athletes have the exact same FTP, the metabolic origin of how that energy is being produced can be vastly different.

If one athlete has a low maximum glycolytic flux rate, and low VO2Max, while another has a high VO2Max, and high maximum glycolytic flux rate, then sure their current steady state time trial performance in terms of power output will be equal, but the training they need going forward to improve their ‘FTP’ further is completely different! One athlete really needs to work on their aerobic conditioning, while the other needs to decrease anaerobic capacity if they want to improve time trial performance.

Having said that, it is important to realise FTP is not the be all and end all of endurance performance. It may be the main determinant of endurance performance, buts its not the only one. Try telling Mark Cavendish that he will never be a successful cyclist because his FTP is too low and see what response you get.

How is FTP measured/calculated?

This really is a mine field with athletes and coaches alike trying to shortcut the process to find their FTP without really understand what it is, and therefore why this is not possible.

The most common method you will hear about is taking your 20 minute time trial power, and taking 5% off this, some may advise a 5 minute max effort beforehand to reduce the anaerobic contribution during the 20 minute effort.

Another test that has become popular is 2X8 minute efforts, and taking 10% off.

A one hour time trial is by definition very close to FTP, but who wants to do that in testing, and as we will discuss later, knowing this number still doesn’t help you with your training.

Finally another slightly better, but still greatly flawed approach is doing a maximum aerobic power (MAP) step test and taking a percentage of this number as the FTP.


Why these tests fail

The 20 minute test and 2X 8 minute test rely heavily on correct pacing, and motivation from the athlete, they are also brutally tough. Worse is the fact that they don’t end up giving you an accurate number, as depending on the physiology of the athlete, they may be able to sustain this level of effort for an hour or longer without much fatigue, or they may have had their power fall off a cliff moments after the test duration had they carried on.

A MAP test does not rely on pacing, but it is pretty brutal going to failure like this test requires, and it still uses a percentage of final power to determine the FTP which is not going to be correct for most athletes.

A one hour time trial paced well is a brutal task, but should yield an accurate FTP number. But this doesn’t tell us anything about why the power number is what it is, or how to improve it.

What do we recommend then? Cue lactate testing.

Lactate testing to find the threshold and to determine future training

Using lactate testing it is possible with a sub-maximal test, which does not rely on athlete pacing or motivation, to find the threshold or ‘FTP’. ‘Blood doesn’t lie’ is a common saying in lactate testing and its true. By looking into what is actually happening in the body we can tell a great more information than power or heart-rate alone could ever tell you.


Now after all that we have written, we are going to say something which may surprise you.


The threshold or FTP number DOES NOT MATTER.


MPS athlete Hannes Bergström Frisk has an 'FTP' of almost 400 watts, and doesn't pack a sprint at all, but that doesn't mean you can't compete in a 'sprinters' race, as he proved when he won the national criterium championships of Sweden

This is not because it’s not important, it is, we already said it’s the most important metric in endurance performance. The reason the number doesn’t matter, is because what really matters is knowing how to improve it.


Using lactate testing we can see physiological breakpoints, and how the power/pace the athlete is working at is being composed. Rather than doing more training based off what power the athlete has been producing in training, we can clearly see why the FTP is where it is, and what would facilitate an improvement in this area. Not only this, but we can see why an athlete performs well in shorter efforts or events, why their short term power is exceptional, or perhaps why they are a complete diesel.


By looking at the lactate data we get a full view of the performance from the athletes body, rather than just an output from a device strapped to their bike. This allows us to tailor training to target individual parts of the physiology to improve whichever part of their performance will yield the most benefit.


Lactate testing can therefore:


· Determine your threshold or ‘FTP’ more accurately than another method

· Determine this threshold more conveniently, with less effort, and with greater repeatability for progress measurement

· Allow training zones to be set from the processes that are occurring within your muscles and body rather than as percentages of an arbitrary number

· Allow training time to be maximised and less time wasted

· Show us exactly why the FTP is where it is, and exactly what is needed to change in order to improve it

· Shows us what is needed to improve other aspects of performance (e.g. short term power, or fatigue resistance)


Let lactate testing help take your training to new levels, Check out our lactate testing and training services today.