This is a one hour video to help you do a 20 minute FTP (Functional Threshold Power) test on an indoor trainer.
It’s not easy to maintain the effort and motivation to ride hard for 20 minutes indoors and this video is intended to help. It probably needs a bit of ‘fine-tuning’ and it would be interesting to get some feedback from anyone who gives it a go.
It consists of a 20 minute warm-up based on the protocol used by British Cycling and Team Sky followed by a 20 minute sequence chasing three cyclists. The footage is fast and is accompanied by high-tempo music.
Please note that you will need to have an accurate Power Meter in order to get accurate results. If you just have a Heart-Rate monitor you can use the test to estimate your Threshold Heart-Rate. There is much debate about estimating FTP on an indoor trainer including the issues of testing indoors compared to outdoors. I recommend you read the resources at the foot of the page before doing any testing.
Testing Indoors Compared to Outdoors
Doing tests indoors is subject to several issues. Some people find they perform better indoors, others not so well while others perform just as well as riding outdoors. Your performance will be influenced by your mood, motivation, etc. but the build up of heat is probably the biggest influence to reduce your power output. This is especially important during a prolonged effort lasting 20 minutes.
I have done several tests comparing the performances using the video to what the riders can achieve riding outdoors and have found that the results are quite an accurate assessment of what the cyclists can maintain for a 60 minute effort outdoors. Heart-Rates have been the same or higher during the indoor tests suggesting that heat build-up is a major influence. Conditions need to be taken into account but an interesting article by F. Grappe found that cyclists rode up to 10% more efficiently outdoors. Alex Simmons findings of a frequent 10% lower power output indoors.
Doing the FTP Test
What you need:
- Power meter
- Heart-rate monitor
- Software to measure the 20 minutes
- Ample cooling
- Lots of motivation
Warm-up : You need to be well rested and motivated to do an FTP test, especially on a turbo trainer, and maintaining a high power output for a prolonged period indoors is not easy for many people. A good warm-up is crucial. The resistance shouldn’t be set so that you start feeling too tired during the warm-up: you should start light sweating and become aware of your breathing after about 10 to 12 minutes. Your heart-rate should get progressively into your Tempo zone.
The Test : It’s all about Pacing. Don’t start too hard. Most testers advise people to split the 20 minutes into 3 sections such as:
- 7 minutes riding just below (say 90%) of what you feel you should be able to maintain for 20 minutes.
- 7 minutes at 100% of what you feel you could maintain for 20 minutes.
- 6 minutes at whatever you can do until the end.
- Go as hard as you can for the last minute.
Before doing the test I would recommend do a couple of run-throughs the week before you do the test. Use the first session as a workout in itself so that you get to know the ride and roughly what resistance settings to have and assess whether you have sufficient cooling. It will also give your mind an idea of how long 20 minutes is. On the second play through you can get to know the video and soundtrack better and maybe have a go at doing a sub-optimal test to practice a suitable pacing strategy.
Interpreting the Results
Andrew Coggan suggests that after your 20 minute test you take 95% of this figure to get your one hour FTP. However, for many people, a more accurate assessment may lie between 89 to 94% (Alex Simmons).
However, it’s increasingly accepted that testing indoors results in a 10% lower power output, so allowing for this your 20 minutes indoor test might be an accurate estimate of your FTP.
Using the FTP Test for Determining Heart-Rate Zones
Due to the issues with heat and each individual’s differing ability to cope with heat, heart-rate can vary from one session to another as the room temperature and cooling ability varies. However, the average heart-rate during the 20 minute test is a good estimation of your Functional Threshold Heart-Rate.
Have a look at the Intensity Levels page in the Video Lounge.
Don’t rely on a single test and don’t get hung-up on trying to be 100% accurate. If you want to be 100% accurate go to a professional lab. Don’t forget that you will be basing your training sessions on Zones and your equipment won’t be 100% accurate either. Remember to keep it fun and enjoyable.
Training and Racing with a Power Meter : Hunter Allen and Andrew Coggan. Velopress.
The Power Meter Handbook : Joe Friel
Joe Friels Blog : Indoor vs Outdoor Bike Performance