Threshold power
March 8th, 2011 by Ashleigh Moolman Pasio
In my training blogs, I often refer to threshold power.
Some might be asking, what is threshold power, why is it important and how do I measure it?
Your functional threshold power (FTP) is the exercise intensity at which lactate begins to accumulate in your blood, otherwise known as your lactic threshold (LT).
FTP is important, as it is a powerful predictor of your endurance performance ability.
Knowing your FTP is not only important to predict your endurance performance ability, but it is also a very important training tool, specifically useful in interval training.
If you know you FTP, you can determine your power levels, which can then be used to determine the power you should be holding in specific interval sessions or during regular training rides.
Power levels:
- L1 – Active recovery (0% – 55.6% of FTP)
- L2 – Endurance (56% – 75.6% of FTP)
- L3 – Tempo (76% – 90.8% of FTP)
- L4 – Threshold (91.2% to 105.6% of FTP)
- L5 – VO2 max (106% to 120.8% of FTP)
- L6 – Anaerobic capacity (121.2% of FTP and above)
There are numerous methods of measuring FTP, ranging from lab tests to specific training tests.
However, the most direct estimate of your FTP will be obtained by simply doing a 1 hour time trial. Your average power for this hour effort is then your FTP.
As it is generally quite hard for the average person to pace themselves well over a 1 hour of hard effort, the most common method of determining your FTP is to do a full out 2o minute time trial. This time trial can be performed on any terrain, however a 20min climb is advised as it is easier to hold high power while climbing.
The average power over the 20 minute effort is then multiplied by a factor of 0.95 to more accurately predict your FTP.
This sounds very technical, but mastering it is well worth the effort. The benefits of specific power training definitely outweighs the effort.
