How does Strava estimate FTP?

In this guide, we will talk about how Strava estimated FTP and how you can calculate FTP. Additionally, we will discuss what weighted average power is, what intensity is and what Power Zones are. If you are an avid cyclist or even if you are starting, you may need to know your FTP to also get some additional measures that are important when you are training.

How does Strava estimate FTP?

You may wonder how Strava estimated FTP (or Functional Threshold Power) and here we may have an answer. Strava merely estimates FTP based on what your greatest 60’ effort is on your power curve. There seems to be an algorithm that calculates FTP but there seems to be a downside as having little to no specificity and all power is calculated with factors including GPS, your weight, age and terrain during the ride. 

Your Functional Threshold Power is the maximum average power that you can hold for one continuous hour and it is recommended you test or at least every few weeks to a month while you are training. For instance, if you were to ride a 20k time trial in 60 minutes at an average power of 270W, you could easily calculate your FTP. 

Finally, your FTP is believed to be the keystone to training with power. According to Strava Support, “It allows Strava to determine how hard a ride is for you. You doing 300W might feel much different than someone less trained doing 300W and FTP allows us to gauge just how hard segments, rides, and even weeks or months of training were for you!”.

How can I calculate my FTP?

As we have mentioned, it is recommended to test your FTP at least every few weeks to a month while you are training. But here are some tips on how to get the most out of your FTP training according to Strava Support:

“It’s extremely taxing on your body (and your training program) to continuously push out 60-minute max efforts. It’s also difficult to find a stretch of road where you can ride for 60 minutes uninterrupted and maintain a steady wattage. Thus, the easiest way to calculate your FTP is to test your best average power for 20 minutes. We believe 20 minutes is enough time to stress the same physiological systems as a 60-minute effort would and it is easier to consistently do within your season”.

However, they recommend a tray to reproduce the same conditions during each test, meaning you must use the same stretch of road or at least always use the same trainer/rollers. Moreover, you need to make sure you are fresh, in terms of having some light training load during the previous days. Finally, always remember to properly warm up.

What is weighted average power?

You may probably ride with a power meter and you may notice how your power jumps all over the place based on some factors such as the terrain, grade, wind, among others. The weighted Average Power considers all of the variations and provides an average power for your ride that is a better indicator of your effort than simply taking your average power. 

Training Load

The Training Load is calculated when comparing your power during a ride with your FTP and seeing how much load you put on your body during the workout. Training load seems to be the perfect way to determine how much rest you may need after working out.

Total Work

As you may have noticed or you may know, Total Work is expressed in kilojoules (kJ) which is simply the sum of the watts generated during your ride. As indicated on Strava Support, there is a close one to one ratio with Total Work and Calories expended during a ride.

What is Intensity?

Intensity indicated how difficult the ride was when compared to your FTP. Strava looks at your weighted average power for the ride and compares it to your FTP. “If your Weighted Average Power was 250W and your FTP 300W, the Intensity would 83%. It’s very possible to have an Intensity of over 100% if the ride was shorter than an hour”. 

  • Endurance / Recovery Ride – 65% and lower
  • Moderate Ride – 65-80%
  • Tempo Ride – 80-95%
  • Time Trial or Race – 95-105%
  • Short Time Trial or Race – 105% and higher

What are Power Zones?

We have to consider how your Power Curve is meant to show your best effort during a given period of time and in contrast, Power Zone charts take each 1 second of power of your ride and put it into a bucket. The buckets are based on your FTP as follows and according to Strava Support:

  • Active Recovery (<54% FTP) – Social pace with very little physiological effect on your body. Can be used in between intervals and for recovery rides.
  • Endurance (55% – 74% FTP) – Easy pace that you could ride all day long. Conversation is still possible with little concentration required.
  • Tempo (75% – 89%  FTP) – Brisk pace that can be maintained for a few hours that requires concentration when riding alone. Breathing in tempo is rhythmic and may become strained at the upper end of this zone.
  • Threshold (90% – 104% FTP) – Moderate to hard effort and leg sensations that can be maintained for up to 1 hour. Conversation is difficult and concentration is required.
  • VO2Max (105% – 120% FTP) – Power that is primarily taxing your VO2Max system. Leg sensations are high and conversation is not possible. VO2Max can be maintained for 3-8 minutes.
  • Anaerobic (120% – 149% FTP) – Extremely hard efforts with severe leg sensations that can be maintained for 30 seconds up to 3 minutes.
  • Neuromuscular (>150% FTP) – Sprinting power that is taxing your neuromuscular system and can be maintained for 1-20 seconds.

Why is this blog about How does Strava estimate FTP important?

As we have discussed how Strava estimated FTP, we can conclude that Strava merely estimates FTP based on what your greatest 60’ effort is on your power curve. There seems to be an algorithm that calculates FTP but there seems to be a downside as having little to no specificity and all power is calculated with factors including GPS, your weight, age and terrain during the ride. 

Finally, we have discussed how Functional Threshold Power or FTP is the keystone to training with power and it may allow you to determine other important metrics. Remember to calculate your FTP at least every two to three weeks or a month, recreate or reproduce the same conditions every time, don’t overtrain or demand too much during the previous days and properly warm up.

Please feel free to leave any comments or thoughts about the content of this article!

Frequently Asked Questions (FAQs) about How does Strava estimate FTP

What is FTP in Strava?

FTP in Strava means your Functional Threshold Power which is meant to be the maximum average power that you can hold for one continuous hour. It is said to be the keystone to training with power and it allows Strava to determine how hard a ride is for you.

How is the FTP zone calculated?

FTP zone can be calculated by subtracting 5% from your FTP Test average output number. The result will be an accurate estimate of the average output you could hold for a period of 60 min. For instance, if your average output is 100, find 5% (100×0.05=5), then you need to subtract it from the total number (100-5=95). 

What is the average FTP?

Average recreational cyclists would be about 2.5-3.0 Watts/Kg for FTP. People who race regularly may be between 3.0-3.75. You get above 3.75-4.25 and those are local elite racers. Anything over 4.25 is a domestic pro and it goes up from there.

What percentage of FTP is a sweet spot?

The percentage of Sweet Spot occurs at 83 to 97% of your FTP and riding here can help improve the aerobic, steady-state that characterizes FTP. Sweet Spot gets its name because it is said to be a balanced amount of intensity and volume.

What is a sweet spot in cycling?

The sweet spot in cycling is a balanced amount of intensity and volume that increases an athlete’s functional threshold power (FTP) and improves endurance. In the figure below, the “sweet spot” occurs between a high level/zone 2 and level/zone 4 or 84-97% of one’s FTP.

References 

Support.strava.com 

Power Analysis Features 

Was this post helpful?