What is Functional Threshold Power?
Functional Threshold Power (FTP) represents your ability to sustain the highest possible power output over 45 to 60 minutes, depending on whether you’re a trained athlete or not. As a result 95% of the 20 minute average power is used to determine FTP.
Why measure FTP?
Regular assessments of your FTP give you an indication of whether you are improving your performance. Plus, FTP provides a good ‘benchmark’ on which to base cycling-specific training zones.
How to measure your FTP
The best way to measure your FTP is with a 20 minute test on the Wattbike smart bike. Once you’ve completed the 20 minute test, note your average power and average heart rate.
Tip 1: Make sure you start the 20 minute test at an intensity you can sustain throughout but also one that allows you to give maximal effort. The above image shows an even well-paced 20 minute test.
Calculating your FTP
Your FTP score is calculated using 95% of your average power across your 20 minute test.
FTP training zones defined
Once you have calculated your FTP score, you can use this as a base for your training zones:
| Training Zone | Purpose | Physiological adaptions | How this helps | Average Power | Average HR |
| Zone 1 | Active Recovery | Increase blood flow to muscles to flush out waste products and provide nutrients | Promotes recovery and therefore training response | < 55% | < 68% |
| Zone 2 | Endurance | Improves fat metabolism and ability to use oxygen, produce power and increases efficiency. Increases economy | More efficient use of energy. Able to produce more power with the same level of effort, works on technique/skill | 56-75% | 69-83% |
| Zone 3 | Tempo | Improves carbohydrate metabolism, gives fast twitch muscle slow-twitch muscle characteristics | Improved sustainable power, good for all cycling events | 76-90% | 84-94% |
| Zone 4 | Lactate Threshold | Improves carbohydrate metabolism, develops lactate threshold, changes some fast twitch muscle to slow-twitch | Improved sustainable race pace, useful during tapering or pre-competition periods: too much time in this zone can cause staleness | 91-105% | 95-105% |
| Zone 5 | V02max | Develops cardiovascular system and VO2max, improves anaerobic energy production and speeds turnover of waste products | Improved time trialling ability and resistance to short-term fatigue | 106-120% | >106% |
| Zone 6 | Anaerobic Capacity | Increases maximum muscle power, develops cardiovascular system and VO2max, increases threshold | Sprint speed, ability to accelerate away from a group and tolerate lots of hard work, such as mountain climbing | 121-150% | N/A |
How to improve your FTP
You can improve your FTP score by following one of our structured training plans.