What is FTP in cycling and how do I test and improve it?

Recently picked up a power meter or indoor bike and want to get started working on your Functional Threshold Power? Here's everything you need to know

Indoor training on a Wattbike
(Image credit: Future)

Cycling Weekly created this content as part of a paid partnership with Wattbike. The contents of this article are entirely independent and solely reflect the editorial opinion of Cycling Weekly.

Getting started with indoor training can be an absolute game-changer for your riding, but understanding your FTP could be essential to help you maximise the gains.

The term is ubiquitous amongst cyclists and is a common measure of fitness and can even be a source of competition among some riders, but what is it?

FTP stands for Functional Threshold Power and is effectively a measure of the power you can hold for an hour, measured in watts.

But there is a lot more to it than that.

Here we break down all the ways you can use your turbo trainer or indoor bike to help you understand, measure, train and improve your FTP.

FTP is expressed in terms of watts per kilo – the power produced divided by the rider's weight. It's a nominal value based on the theory that you would need more power to go at the same speed, and less if you lose weight – even though taking slope, aerodynamics and rolling resistance into account that isn't always the case.

Where once power meters were reserved for the pro peloton and very dedicated athletes, they've become much more popular in recent years and the arrival of indoor bikes like the Wattbike Atom (opens in new tab) and smart turbo trainers has meant that even more riders have access to the magical world of wattdom.

Knowing how to train with a power meter is crucial to getting the most from one – and understanding FTP is pretty much the first step.

What does FTP tell you?

FTP is often used as the most accessible measure of fitness – when combined with weight and ideally heart rate data.

If you're training for an event, you can measure FTP every four weeks to track progress. If the number goes up without your weight also increasing, you should have become fitter.

The ideal situation is that FTP has gone up, weight has gone down and heart rate to produce the same power is lower – but unless you're starting from a fairly low level of fitness it would be incredibly hard to manage all three.

Coaches and athletes will usually focus on a range of power figures - for example, five-second, one minute, and five minute, as well as FTP numbers when determining a rider's programme - however, FTP still holds a very strong significance. Of course, if shorter efforts are more important to your goals, you may wish to focus your attentions there, instead.

What are the limitations of FTP?

Whilst FTP is an effective measure of fitness, it lacks specificity.

A time trial rider trains their body to cope well with long, sustained efforts. A sprinter focuses on short, sharp accelerations.

The result is that if FTP is used as the only measure of fitness, then the tester will probably appear to be the 'stronger' rider on paper, but the sprinter has their own set of skills which certainly can't be overlooked.

If you're focusing on improving your sprinting, then it's possible you might even lose a little fitness on the endurance side – but a dropped FTP would not represent a failure.

When testing FTP, therefore, it's worth bearing in mind what you've been working on of late, and perhaps testing in conjunction with shorter efforts such as an all-out max five-second assessment.

Indoor training apps such as Zwift, TrainerRoad, and Wattbike Hub include FTP tests, which can be used to set intervals for training, while The Sufferfest (now Wahoo X) has its own selection of comprehensive fitness tests, to give you an accurate measure.

How can you measure FTP?

There are several methods available.

The best option is to complete a time trial that will take about an hour – for example a 25-mile time trial. It's much easier to get your best number when there's another one pinned on your back.

Second best is to complete a one-hour criterium race and take the 'normalised power' number provided. Normalised power uses an algorithm to smooth out accelerations and is surprisingly accurate.

Next, there's the 'FTP test'. The session given in Hunter Allen and Andrew Coggan's book Training and Racing with a Power Meter may be growing in age (our edition dates back to 2010), but it's still widely used and most training apps still stick with the protocol:

  • Warm-up: 10 minutes spin then 3 x 1 minute fast cadence, 1 minute easy, 5 minute spin
  • 5 minute all-out effort - go as hard as you can (press 'Lap' at start and finish)
  • 10 minute recovery
  • 20 minute all-out effort (use that 'Lap' button again)
  • Cool down

Multiply the 20 minute effort by 0.95, to give you the number you'd get over an hour*.

*As a side note, personally I've always found that the number attained during the 20 minute indoor test, and my actual one hour performance in time trials outdoors, match up almost exactly. Perhaps it's the effect of overheating indoors (even with a fan!), the lack of movement on a turbo, the ability to push harder in a race, or maybe even a bit of laziness. These are individual factors though – but certainly do not be surprised if your 'indoor' number is lower than your 'outdoor' number – this is very common – just make sure your expectations in training line up. 

How do you go about improving FTP?

Your FTP will be used to set your training zones.

The exact percentages and training zones vary depending upon the coach that's using them - but in 'Training and Racing with a Power Meter' Allen and Coggan promote those below:

ZonePercentage of FTPUse for
1<55%Active recovery
256-75%Long, endurance rides
376-90%Tempo rides aimed at improving endurance at high effort
491-105%8-30 mintue intervals focused on improving FTP
5106-120%3-8 minute 'V02 max' intervals
6121-150%30sec-3minute efforts focused on improving anaerobic capacity
7N/AEfforts less than 30 seconds, sprinting, neuromuscular power

With these zones, you can establish which systems you want to target. Ideally, this will be periodised so you're working on different attributes to suit your goals through the year.

If improving your FTP is a target, then something like this strength building block of 2x20 would be a good place to start.

Tools like the Pedalling Effectiveness Score from Wattbike can also help you improve your FTP, by giving you an insight into exactly how efficient your pedal strokes are.

With a Wattbike Atom for example, you can measure, adjust and tweak your pedal technique live to improve your pedalling efficiency, potentially increasing your FTP as a result.

There's more indoor cycling sessions suggested here, with information on the target zones and what you'd expect to get out of them.

How 'good' is your FTP?

Firstly, the numbers vary depending upon the power meter used. Only very slightly, by a couple of per cent – but for that reason it's not worth setting up bragging rights between you and your friends. Let your actual performance on the road do that.

If you're desperate to know, however, then there are several handy readily available charts which show average ability across athletes when it comes to FTP, five minute, one minute, and five second power output.

Checking out your performance across all four durations is a really good way of establishing your strengths and weaknesses as a rider. Almost essential if you want to compete in competitive events outside of the endurance realm of time trials.

The basic numbers for FTP - as listed by Allen and Coggan - look a bit like this:

World Class ProDomestic ProCat 1Cat 2Cat 3Cat 4 and 5
Male5.6 - 6.4  w/kg5.2 - 5.7  w/kg4.6 - 5.3  w/kg4.0 - 4.7 w/kg3.4 - 4.1  w/kg2.4 - 3.6  w/kg
Female5.3 - 5.6  w/kg4.5 - 5.2  w/kg4.0 - 4.6  w/kg3.5 - 4.1  w/kg2.9 - 3.6  w/kg 2.0 - 3.1  w/kg

These numbers are based on the US system where categories start at five which is worth bearing in mind.

Alternatives to the FTP test

For one reason or another, the traditional FTP test might not be for you.

If it's the intensity that's putting you off, you should consider trying a ramp test alternative to the conventional FTP test.

Zwift and Wattbike both have the ramp test that might be perfect for your skills - after a brief warm-up, you will then perform a series of one-minute intervals with the power increasing each time.

You will start at 100 watts and then every minute the power will increase until you can't turn the pedals any longer.

Once you stop pedalling, the apps will then calculate your FTP based on how far you got in the session.

It's a less demanding session than the 20-minute FTP test and will still offer a good idea of where your FTP currently sits.

The Sufferfest also offers a revolutionary new version of the ramp test, the Half Monty, which will give you three fitness benchmarks – the FTP, maximal aerobic power (MAP), and lactate threshold heart rate (LTHR).

Or if these options are too general for your tastes, The Sufferfest uses '4DimensionalPower' (4DP), which looks at five-second, five-minute, 20-minute power as well as a one-minute effort following fatigue. The result is a picture of the rider's Neuromuscular Power, Anaerobic Capacity, Maximal Aerobic Power and Functional Threshold Power. Looking at all of these figures each month would give an incredibly accurate representation of overall fitness.

Wattbike also has its own selection of fitness tests, including the classic 20-minute FTP test, a tough maximum ramp test to find your maximal minute power and your max heart rate, the Submaximal Ramp test, and a short, sharp three minute aerobic test, which all help you find your benchmark.

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