Now you’re playing with power!

After taking delivery of, and setting up, my Wahoo KICKR SNAP smart trainer, the first thing I did with it…was leverage its power meter and perform an FTP test.


FTP, or “functional threshold power,” is the maximum amount of power you can put out through the pedals sustained over one hour – by which time, your muscles may be at their threshold of holding lactic acid, a natural byproduct of exercise and an agent of fatigue. This metric, measured in watts, has long been held as a benchmark by which a cycling athlete’s workouts should be based on. The thinking is, once you know your FTP, you now have a basis to structure your training zones around – which can then inform your training and workouts. The middle-term objective is to raise your FTP in future tests.

So it makes sense, then, for me to do an FTP test at the earliest possible time…if I’m going to maximize the use of the KICKR SNAP.

The Fitbit app allowed me to set a custom heart rate zone, seen here in green, roughly equivalent to what I believed then was my functional threshold heart rate, +/-5%.

Previously, prior to having my own power meter, I had already done an FTP test, but mainly to establish my FTHR, or “functional threshold heart rate.” Simply, this is what you would expect your heart rate to be while cycling at FTP.

Since power meters are not cheap, a heart rate monitor was the next best thing to train against, but it’s not without its limitations. Chief of these is heart rate’s susceptibility to external influences – such as caffeine intake, a bad night’s sleep, even a nervous or anxious mental state. Power measurements are supposed to eliminate that external influence, as they are computed solely via applied leg torque and pedaling cadence. With power data available, heart rate data now becomes a real-time barometer of your physical condition.


Since FTP is the maximum amount of output power you can sustain over an hour, you could probably do that. However, there are other accepted ways of testing for FTP without having to spend so much time.

I went with the 20-minute FTP test. In reality, this test requires quite a bit of warmup, pacing, and preparation, which means the “20-minute” FTP test really lasts a minimum of 56 minutes, plus any cool-down you need (and you will need it, as an FTP test is never easy).

As shared by Global Triathlete Network, the full procedure of a 20-minute FTP test is below:

Photo credit: Global Triathlon Network. Click on the photo for the source video.

That’s quite a bit of prep work you need to do before you get to the “meat” of the test, the twenty-minute all-out FTP effort.

I find that it’s very important you pace yourself well when you attempt this. You want to keep enough in the tank and in your legs to last through the fast-cadence and initial five-minute all-out blocks. However, you also want to ride as hard, yet as measured, as you can, such that when the final minute of the twenty-minute all-out FTP effort ends…you, your lungs, and your legs are all thoroughly cooked.

Once your test is done, calculating FTP is a simple matter of taking your average power through the twenty-minute all-out FTP effort, then taking 95% of that. Congratulations, you now have your FTP!


For a very long time, I was curious about how exactly Strava “guessed” my power figures whenever I uploaded rides to it. It’s probably the result of some sort of algorithm, and not really worth reading too much into, as it’s not based on any actual direct measurements, hence not very scientific.

Screenshot from the Wahoo training app.

Now that I know my FTP…while it’s not all that high, it just makes sense. Riding the KICKR SNAP in erg mode (where it attempts to keep you at a preset power level, regardless of your cadence or gearing), at just under my FTP, it feels very believable that I can sustain that sort of effort for an hour. It feels like I judged my efforts in my FTP test just fine, and it’s a good benchmark for the next six weeks…the time where many people would say is best to repeat your FTP test, to see if you’ve had any progress.

As American cycling legend Greg LeMond is fond of saying, “it never gets easier – you just get faster!”


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