Bike Testing (10 Mile TT and FTP) - Working out your HR and Power Zones
Cycling is a sport based around speed and power but how do you know you are getting the most out of each training ride? This article explains how power and heart rate can help dictate your training efficiency and staying in the right zone for your particular training sessions.
What is Functional Threshold Power and Lactate Threshold Heart Rate?
Functional Threshold Power (FTP) and Lactate Threshold Heart Rate (LTHR) are terms used to describe a condition called Lactate Threshold. Physiologically, this is considered to be the point when the body accumulates more lactate in the muscles than it can dissipate. It is also thought of as an intensity that an athlete could sustain for approximately one hour. For endurance athletes it is the speed they are going, the power they are outputting at this point that fundamentally dictates how fast they can race. Through training, the purpose is to stress the physiological systems enable a higher power output and therefore speed at this same point. Cyclists have the advantage of technology to estimate what these outputs are and therefore train more within their specific zones suitable for them.
What are Power Profiles?
Power Profiles are calculated by working out the average power sustainable over set times: 5 seconds, 1 minute, 20 minutes and 60 minutes. This is converted into Watts/Kg to normalise the data and put on a scale compared to the very best athletes in the world to approximate the relative standard they are at compared to against all the other cyclists. This standard is of less importance than the over all shape of the graph. In Fig. 1, the athlete is clearly relatively stronger in the right hand side of the graph (as the duration increases) than the left hand side. Therefore, this athlete is suitable for the longer time trials. However if the power profile was sloping down from the right, it would indicate that the strengths lay in the very short sharp sprints. It could be that the individual may have a rise in the middle and be particularly strong over the 5 minute distance. This person would be better suited at attacking in the final few minutes of a cycle race rather than waiting for the sprint to the line or going on an early breakaway. As endurance athletes who do not have the assistance of a peloton to shield them (legally), triathletes would be looking to improve the right hand side of the profile by working in the correct zones to simulate stress in that area.
Fig. 1: The Power Profile of a top age-group long course triathlete. Notice that the 60minute out put is relatively low? This is likely to be because this particular athlete does not race with a power meter and does few reps up to an hour long without recovery. This is an area he could improve in their training
What about Heart Rate?
Does the above mean that everyone should only use power to train and heart rate is void? Not particularly. Power is an output and heart rate can be considered as a process to produce that out put. The best possible way to train would be to use your heart rate in conjunction with a power meter. This means if you are supposed to hit 250W at a heart rate of 165BMP, but your heart rate is considerably higher or lower, then immediately you can sense something is wrong and adjust your training (or in many instances fluid intake!)
Sadly though not everyone has the luxury to train with both systems. Therefore, we can use the LTHR to still work within the same zones and ensure efficient training.
What happens if I don't use power or Heart Rate Data?
We understand that some athletes prefer not to use either heart rate or power as a method for measuring their training. For example many people prefer to use feel. That is fine, but as you can imagine when it comes to working with a coach remotely, it is always easiest to have some sort of data to work with which can improve the quality of feedback.
If you do not use either method, or are unsure of which of our training plan bike portions you should be using, we recommend doing a 10 mile time trial. This short test will give you an idea of what is sustainable and what is unsustainable for 20-35 minutes or so and will give you a fee for what would be about a 6-7/10 on the RPE scale. If you record your time, it gives you a gauge of your standard for your training plan.
How do I calculate my FTP and LTHR?
The testing process for calculating your zones are based around a test called an FTP test.
The FTP test is very simple, yet very effective: 20 minutes as hard as you can go. It is only 20 minutes because if you were to do 60 minutes, not many people would enjoy re-testing every month or so! It has been shown that the difference between the average power and heart rate over 20 minutes and over 60 minutes tends to be approximately 5% loss. Therefore, we take the FTP and LTHR as 95% of the results from the 20 minute test. We also introduce a 5 minute max power test 15 minute before the 20 minute test. This is to help create the power profile above as well as serves the purpose of waking the systems up! As triathletes, we always recommend doing this test in aerobars and aiming to remain seated throughout so the test is as specific to racing as possible.
10 Mile TT
For our downloadable training plans we have based cycling ability around a 10 Mile Time Trial test, as often, it is a result that cyclists will remember. If you haven't done a 10 Mile Time Trial before, and wish to complete one in order to see which category you fit in to, here is how you would do it:
1) Find and measure an appropriate route. Ensure that it is as safe as possible (that you are not turning into on coming traffic for example) and that it is relatively flat.
2) Warm up for 30 minutes prior to the test, do some easy spinning to wake the legs up, followed by some short bursts to increase your heart rate.
3) Go for it! This will take the average person between 20 and 30 minutes to complete so you can afford to go hard from the start. Get into the aerobars to simulate race conditions as much as possible if you have them.
Top Tip: A 10 mile TT can also be used as a substitute for the FTP test (above) so that you can work out your power zones (if you train with power) as well as your heart rate zones. In our training plans, all the cycling sessions are based around heart rate, power and rate of perceived exertion (RPE) so you may as well gather all this data now before you start!
Calculating Your Own Correct Training Zones
Please find your correct zones using either power, or heart rate data from your 20 minute test. There are also RPE values so you can use feel as well.