How to get more out of your power meter
Part two of our guide to power meters; take a look if you want to get more out of them!
Using a power meter on a bike has become an essential tool for athlets who want to improve their performance. It provides a precise measure of the power output, which helps athletes to train smarter and achieve their goals. However, it is not enough to just collect power data; knowing how to interpret it correctly is equally important.
Athletes should understand two critical concepts: decoupling and Intensity Factor (IF). Decoupling is a measure of how much the heart rate (HR) drifts relative to power output during a sustained effort, such as a long climb or time trial. When a cyclist begins a sustained effort, the heart rate increases rapidly and reaches a steady state after some time.
What is Decoupling?
If the athlete maintains a consistent power output, the heart rate should remain constant, indicating that the body is efficiently delivering oxygen to the working muscles. However, suppose the heart rate begins to drift upward. In that case, it is a sign that the body is struggling to maintain the same level of effort, and the efficiency of its oxygen delivery system is declining.
Decoupling is calculated as the percentage increase in heart rate relative to power output over a given period. For example, if a cyclist maintains a power output of 250 watts (W) and a heart rate of 150 beats per minute (bpm) for the first hour of a ride and then maintains the same power output but sees their heart rate increase to 160 bpm in the second hour, decoupling would be calculated as follows:
Decoupling = ((160 bpm – 150 bpm) / 150 bpm) x 100% = 6.7%
What does this mean?
- A decoupling value of less than 5% is generally considered good, indicating that the body is maintaining efficient oxygen delivery to the muscles.
- A value between 5-10% suggests that the body is starting to struggle
- A value greater than 10% indicates that the body is no longer delivering oxygen efficiently, so the effort level needs to be reduced, or distances need to be reduced until the athlete’s fitness has improved enough to maintain <5% decupling.
Decoupling is a valuable metric for long-distance events, such as Ironman triathlons or ultra-endurance cycling races, where efficient oxygen delivery is essential for maintaining a steady effort level. By monitoring decoupling during training, cyclists can identify their limits and work on improving their efficiency to maintain a steady effort for extended periods.
What is Intensity Factor?
Another essential metric for power-based training is Intensity Factor (IF). IF is a measure of the intensity of a workout relative to the cyclist’s maximum sustainable power output. It is calculated as the ratio of the average power output during a ride to the cyclist’s Functional Threshold Power (FTP), the highest power output the cyclist can sustain for an hour.
For example, if a cyclist has an FTP of 300W and maintains an average power output of 240W during a ride, the Intensity Factor would be calculated as follows: IF = 240W / 300W = 0.8
IF values range from 0 to 1, with 0 representing no effort, and 1 representing the highest sustainable power output. The higher the IF, the more intense the workout, and the greater the training stress. IF values are mainly used to determine the appropriate level of effort for specific workouts.
Athletes should understand the relationship between decoupling and IF to get the most out of a power meter. Decoupling is an indicator of the body’s ability to maintain efficient oxygen delivery to the muscles during sustained efforts, while IF measures the intensity of the workout relative to the cyclist’s maximum sustainable power output.
How Can They Be Used?
Together, they provide a comprehensive picture of an athlete’s fitness level and help them to optimise their training. For example, an athlete who wants to improve their efficiency and endurance may focus on reducing their decoupling value. Whereas an athlete looking to race at a shorter distance race such as standard distance may want to use IF to find out at what intensity they can ride whilst still being able to run well of the bike.
Overall, both decoupling and IF can be important for athletes who are starting to use power meters in training and help inform them of their fitness levels and the intensities at which they can sustain good running.