I spend a lot of time talking about the importance of Functional Threshold Power in  bike training so I thought it would be best to write it up in one place. So here we go….

The importance of FTP for training

Your FTP is the highest power you can sustain on the bike for an hour and is determined by how much power you can put out before the lactate (a by-product of exercise at higher intensity) begins to accumulate in your blood faster than you can flush it out, and you get that familiar heavy burning feeling that you causes you to slow down. (You could also measure your lactate threshold, LT, but given the expense and inconvenience of measuring your LT, we stick with the far more accessible FTP test, which gives very similar results).

By training at or around your FTP you’ll be able to raise that threshold so that, as your body get more efficient at dealing with the lactate, you’ll be able to go harder for longer. 

Typically riders will retest their FTP every 4 -6 week, both so you can ensure you are still training at the right level, and so you can track your progress – if it’s not going up then you know you need to adjust your training plan. The test itself is also great (but painful) training.

How to test your FTP

To find out your FTP there are various tests, the most common one being the 20 minute test. If you have access to a Watt Bike or another bike that records your average power for a work out you can do your own test (this is a hard test so you want a good level of fitness before doing it. Another alternative is a 4 min ramp test on bikes such as the Matrix IC7).

After a good warm up, start a new workout and then hold the maximum power you can sustain for 20 mins (see the 20 minute test on a Watt Bike). Be aware what feel doable at 5 mins in will not feel doable 15 mins in so start off conservatively. Record your average power for the 20 mins and then calculate 95% of it to get your FTP. For more detail, see Joe Friel, the daddy of triathlon training.

Training zones

You can use the calculator on the Watt Bike website to calculate your zones. You can then use these zones for most of the training plans that you’ll find online. The following table (adapted from Suffer Fest) also shows you how to calculate the zones and what each should feel like:

Zone Training type % of FTP What does it feel like
Zone 1 Active recovery < 55%
  • Easy spinning
Zone 2 Endurance 56-75%
  • All day pace or classic long slow distance (LSD) training
Zone 3 Tempo 76-90%
  • ‘Spirited’ group ride
  • Greater sensation of leg fatigue
  • Requires concentration to maintain
  • Breathing deeper, conversation possible but halting
Zone 4 Lactate threshold 91-105%
  • Hey. This hurts. A lot.
  • Just below to just above TT effort
  • Continuous sensation fatigue
  • Continuous conversation difficult at best
  • Mentally very taxing  to sustain
  • Such workouts generally only performed when sufficiently rested/recovered
Zone 5 VO2 Max – (3-8 min intervals to increase VO2 Max)


  • My goodness make it stop. Please.
  • Severe fatigue, more than 30 min total training time close to impossible
  • Conversation limited to few breathless words
  • Consecutive days of level 5 work not necessarily desirable even if possible
Zone 6 Anaerobic capacity – short high intensity intervals 121-150%
  • You’d rather rip out your toenails than do this
  • Severe fatigue, conversation impossible

Using heart rate

It is also possible to use heart rate to map your training zones (the above WattBike zone calculator link also allows you to calculate this). This can be useful because many of us don’t have power meters out on our bikes in the real world. However be aware that these zones can be quite approximate, and I find many people’s power and heart rate zones don’t quite match up. I would always use power where I have the choice and heart rate as a back-up.  Also be aware that you could be a minute or so into the zone before your heart rate catches up so it won’t be much use on shorter intervals.

What’s a ‘good’ FTP?

Everyone always wants to know what their FTP ‘should’ be. It’s usually looked at in terms of watts per kilo, so take your ftp and divide by your weight in kilos. The following is a very rough indication:

  • 1 – Beginner
  • 2- Average rider
  • 3 – 3.5 – Regular and specific training
  • 3 .5 – 3.9 – A great cyclist/ triathlete, consistently comes in top 20% of races
  • 4 – Very solid, podium is in sight or a familiar place for you
  • 5 – Elite amateur
  • 6 – What are you doing reading this, you should be training for this year’s Tour!

Obviously this gives you two ways to improve your result, either lose weight or build your FTP. Your current weight and goals will determine which is most effective for you. If you mostly race short, maximal efforts on the flat (e.g. riding Criteriums or track sprint racing) then you’ll mostly want to focus on building FTP and weight isn’t so important. If you’re regularly riding up hills then losing some weight (depending on your current weight) may also be important.

How to improve your FTP

The main way to improve your FTP is to train around that level, using a structured training plan. Here’s an example of some FTP focused work outs –

7 week progressive build workouts with 90 rpm tracklist 

#ThisGirlCan FTP based workout 

Can you use FTP for running?

If you’re a triathlete who also wants to use this approach for your run training the good news is that you can also set your Functional Threshold Pace. The bad news is the test is a whole 10 mins longer and it’s not quite so useful because it sets a pace which would therefore rely on you training on flat ground (or replicating the test gradient) to use it. Again, see Joe Friel for more.

Happy training all, let me know how you get on.

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