WHAT IS YOUR FUNCTIONAL THRESHOLD POWER?

Since the dawn of the online training age, we have become increasingly obsessed with data and metrics. None more so than our FTP. We wear it like a badge of honour, a badge that sometimes… maybe… possibly… every now and then, we embellish a touch… whoops!

Something to bear in mind is that your Functional Threshold Power (FTP) is a moveable feast. We stick a nice tidy number on it but in reality, your FTP changes on a daily basis depending on a number of variables. These include things like how well you slept, accrued fatigue, how warm you are, how well fed you are and even what altitude at which you are training.

In reality, our FTPs should be represented by a power range rather than a specific number because it is intended to represent your aerobic capacity.  Translated, this is essentially the tipping point at which your body can no longer take in enough oxygen to keep up with the production of lactate and buffer the concentration of hydrogen ions that are responsible for fatigue.  As you can probably imagine, your body does not ascribe a specific power output to this tipping point in a strict and consistent way.  In a nutshell though, your FTP is trying to nail down this tipping point and for the purposes of setting up your trainer on RGT, it is certainly sufficient.

Even if your aerobic threshold is changeable, it is still important that your FTP is as accurate as possible. To illustrate why, imagine you have been off the bike for a while, you have detrained somewhat but have not altered your FTP in RGT before trying to perform a threshold focused session.  If your FTP does not accurately reflect your fitness level, you might be trying to perform threshold intervals but in actual fact, you are really hitting your anaerobic energy systems more than desired and fatiguing yourself more than is sustainable.  This fatigue will then likely spill over into future sessions because you simply cannot recover properly before they arrive. All of this can harm your consistency as you struggle to sustain your training volume. The message, therefore, is for better or for worse, your FTP needs to reflect where you are currently at, which we know can be hard for the old ego to take!

What goes into your FTP?

The way we see it, there are two major factors determining what your FTP is: 1) the strength element; and 2) the endurance element.

1)    The strength element

In order to improve your FTP, you need to develop strength so you can push down harder on those pedals and produce greater power.  This is where your threshold and supra-threshold focused sessions come in. Those tough sessions taking you to the edge and back, teaching you to ‘enjoy’ the pain. What these sessions do is raise the point at which your anaerobic energy systems start to really kick in. Your anaerobic energy systems are metabolic processes that produce energy in the absence of oxygen and are responsible for the accrual of lactate and hydrogen ions mentioned above. Build greater strength and your power output will be higher when these systems kick in.

2)    The endurance element

Now this is the element that many do not ascribe the requisite amount of attention. We all know working hard will make us stronger but if you have no aerobic endurance, you will not be able to hold power for very long.

Aerobic endurance focuses on improving your cardiovascular fitness and encourages those metabolic developments we all desire as athletes. Things like increased capillarisation to get more oxygen to working muscles, development of your cardiac output so you can pump more blood per heartbeat, a greater propensity for burning fat for energy as opposed to glucose etc. etc.

The mistake many athletes make is that they do not fully comprehend what low intensity endurance training really means. The main culprits are those that perform their ‘base mileage’ with a group of friends or club at the weekends. These longer endurance rides are where you should be developing your ability to ride for longer before fatigue sets in. When done as part of a group, these sessions can easily slip into a ‘smashfest’ with riders racing up climbs, hitting the front hard and generally having fun (which cycling should of course be) but losing sight of the purpose of the session.  The result is that this supposed endurance session can rapidly devolve into yet another strength focused session.  If you are performing a significant amount of structured high intensity training elsewhere in the week, an endurance ride that turns into a high intensity workout can see fatigue overflow into the next week and the athlete develop chronic fatigue because unwittingly, all their sessions effectively become strength focused sessions.

This is not intended to put you off group riding. The point to make here is that every session should have a clear focus and if your session focus is longer low intensity miles, that power should be kept below about 75% of FTP (the top end of Zone 2 if you use training zones) as much as possible for it to be a genuine endurance session.

Testing for your FTP

As we have discussed, putting a specific number on your FTP is not always helpful.  However, the vast majority of online training platforms do require an FTP to set training intervals, so they are roughly at the right intensity.  They have to use something after all!

Therefore, it is important that your FTP is as accurate as possible, or you could end up training the wrong energy system to that intended by the session objective.

There is a lot of discussion over which testing methodology is the best to use. Here are three of the key methodologies:

Ramp test

Some coaches swear by the ramp test. In short, a ramp test is where every minute the power target increases by a certain amount and keeps doing so until you fail to complete a step at the target power. There are different versions of this test but regardless of the specifics, once you reach failure, a formula is run over that result to predict your FTP or more specifically, the theoretical average power you could hold for a full hour.

Ramp tests are great because they are usually short, around 25 minutes or so (including the warm-up).  They are therefore, the least physiologically demanding form of testing and can be done fairly regularly without requiring tonnes of recovery.

The downside to a ramp test in our opinion, is that they are a bit of a ‘quick and dirty’ methodology.  Because it is so short and essentially takes a result from your final max effort, the formula is relatively complex and has to fill some gaps that other tests do not need to fill.  And anything that requires a greater deal of gap filling through mathematical inputs is likely to be less accurate. Plus, it can favour particular types of riders, i.e. those with great strength but not necessarily a big endurance component to their fitness.

We tend to use ramp tests with inexperienced athletes or those coming back from a big lay off just to give them a starting point with their bike training.

The standard 20-minute FTP test

In this test, after a long warm-up you would perform a 20-minute effort as hard as you can and record the average power for that effort. That average power result is then multiplied by 0.95 to extrapolate out to your FTP or predicted 1-hour power.

This form of test is probably the most commonly used and in our opinion is a step up from the ramp test in terms of accuracy as only a simple formula is used to predict your 1-hour power or FTP.

The major downside to the 20-minute test though, is that it is much more physiologically demanding and therefore, should not be performed as regularly as a ramp test because the fatigue accrued through such an effort will likely overflow into your normal training.

We use the 20-minute test method for athletes that have a good level of fitness but are not perhaps at a level where they could manage a full spectrum test (see below).

Full spectrum testing

This final form of testing can come in various guises. We call it ‘full spectrum’ testing because in essence, it tests all of your energy systems through different types of intervals all in one session.  In the format we use, we test Vo2max power, Anaerobic Capacity (the total amount of work you can do in an anaerobic state), Neuromuscular Power (your max power) and then perform a 20-minute FTP test like that described above.

The logic behind this form of testing is that the 20-minute FTP test should be done at the end because it represents your aerobic capacity (i.e. the max average power you can sustain whilst still in an aerobic state). Therefore, we perform the VO2max and anaerobic efforts to strip away the rider’s anaerobic systems, so those systems are less able help in the 20-minute effort.

The reason we perform this type of test for our more experienced athletes is because we have seen occasions where testing via the ramp or standard 20-minute test on its own has led to a significant FTP inflation. Up to 30 watts inflation in some instances. This means those people were training well outside of the power ranges they should have been training in.

The major downside to this full spectrum testing is how long the session is and how difficult it is. Typically, the session is over 1-hour 30-minutes, and it is brutal. This means plenty of recovery is required afterwards and the riders also need to prepare in a specific way too. We recommend having at least a 12-week gap between full spectrum tests.

How to improve your FTP

Improving your FTP is actually remarkably simple.  You need to balance focused strength workouts with ensuring you consistently perform plenty of low intensity mileage too. The general rule is to look for an 80:20 split, with 80% of your total volume being low intensity sub-threshold training and just 20% made up of structured high intensity work.

The sessions themselves do not even need to be that complicated either. The layer of complication comes when you realise you want more than just a higher FTP and you want to develop as a rider. If you have raced at any level, you will know that a high FTP does not necessarily translate to race wins. Different events emphasise different rider characteristics. So for instance, a course with short punchy climbs like those in the Spring Classics will suit those with a well-developed Vo2max power.  Whereas flatter courses likely to end in a sprint will suit those with good top end anaerobic power. The riders’ FTPs in these scenarios are unlikely to be determinative of success.

Therefore, our advice to you is to figure out what your strengths are, choose events that emphasise those strengths and structure your training around those objectives.

If you need help, that is where well-tailored training plans and experienced coaches come in!