The FTP diaries: A long, meandering relationship with training and watts

With the threat of COVID19 and the reality of my work shift both not accommodating much in the way of riding outdoors, I started training myself using a power meter in the middle of 2020. All the necessary hardware had finally gotten to a somewhat approachable price point, although I won’t deny that all of it still costs the equivalent of a new mid-range bike. I had better make it count, then.

The cornerstone of most power-based training is the FTP test. For the uninitiated, FTP, or “functional threshold power,” is a measurement, in watts, of how much power a cyclist can output for a given period of time – and the usual time benchmark is one hour. In the interest of time, most FTP testing is done over 20 minutes of the hardest sustainable effort a cyclist can muster, After that, taking 95% of that interval’s average power output results in that cyclist’s FTP.

Once FTP is known, it becomes the basis for many a training plan, with six or seven “zones” based off percentages of that FTP figure. Conventional wisdom is to repeat the FTP test after about six weeks as a barometer of progress.

Starting in July 2020, I embarked on my first FTP test with uncertainty in terms of expectations.

How correct is this value, really?

Prior to this, Strava had published an “estimated average power” with each ride I logged since 2013, and it will continue to do so for every cyclist that doesn’t use a power meter. It’s a nice figure to look at, and it could be an ego boosting thing, but emphasis has to be put on the word “estimated.” Unfortunately, if all you’re doing is running the smartphone app, Strava has zero clue of how much power you are making because it has no method of making direct measurements of torque and cadence. It’s nothing more than a wild guess.

So, after years of looking at – and deluding myself with – this “estimated average power” figure, you can imagine how chagrined I was to find out my actual FTP of 126 W, after performing a proper test on the Wahoo KICKR SNAP. At the same time, though, it was a figure I knew was undeniably correct. I rode an honest maximal 20-minute effort and I wouldn’t have been able to better it in my condition at the time. At least, it was a good foundation to start from.

Over the following months it became my objective to improve my FTP. I’m not a racer, and I don’t have interest in joining competitive cycling events. I just wanted to see how far I could push myself in improvements, and how much I could build on that initial 126 W FTP figure. With more training miles and more structured riding under my belt, I was able to make decent gains. A month later I was in the 153 W range, and by March 2021 I had pushed into 185 W.

Maybe, just maybe, I had what it took to get to 200 W?

That question kept getting a negative response for the rest of the year. I was making smaller and smaller gains per FTP test, which was fine, but there also emerged a pattern where posting new personal-best power numbers, inching ever closer to 200 W, would immediately get followed by some reason for me to stop cycling. In the closing four months of 2021, those reasons were injuries. I had a sesamoiditis scare on my left foot in September, which I found was down to incorrect cleat position and got fixed, along with ten days off the bike. More egregiously, I ended the year nursing a nasty left ankle sprain for two weeks. Unable to stand or walk properly without pain, much more ride a bike, this first-ever sprain threw a lot of uncertainty over my future as a cyclist. That put me in a funk.

Fortunately, by the first week of January 2022, the recuperation and binding of my left ankle was at a point where I could dare to get back on the bike and pedal on the trainer. Mindful of my left ankle, I just spun the pedals at a relatively light effort, but did not stop pedaling. I realized how cycling was a non-weight-bearing exercise for the most part, and I could actually do this comfortably for an hour or two.

After that first couple of rides on flat courses, I started progressively loading up my left ankle with more pedaling torque, consistent with medical advice to do more weight-bearing activities by the third week after the sprain. I started pedaling out of the saddle, pushing more torque at lower cadences. The week after, I started on the rolling hills and climbing courses on RGT, pushing more watts up 7% slopes. I even challenged the virtual Passo dello Stelvio again – that steep Italian climb with all its hairpins and slopes exceeding 12% for two hours.

By the last week of January, I was in good condition. I thought of testing myself again. What gains did I get? Had I lost any power in recuperating from the ankle sprain? The FTP test would tell.

I did the test and…I got 194 W. This was the same FTP I had at the end of November 2021. No worries; at least I didn’t lose any fitness, I thought.

But something felt off. I measured that effort perfectly; I didn’t run out of puff midway through the 20-minute test interval and I felt like I had done more than 194.

The next day, I suddenly remembered – when was the last time I checked the air pressure on Hyro’s rear training tire?

Let this be a lesson, kids. Wheel-on smart trainers need consistent rear tire air pressure.

Sure enough, it had been too long. The rear tire on Hyro’s training wheel was at 55 psi; it really should have been at 100. A dozen strokes of a track pump later, I hopped back on the trainer and did another FTP test. Never mind the sheer exhaustion an FTP test typically brings; I sabotaged the last attempt by doing it on a wheel-on smart trainer with a half-deflated rear tire. I felt like I had enough in the tank and in my legs to exact my “revenge.”

As with the previous day, the effort was spot-on. Unlike in previous FTP tests where I went too hard at the start and wheezed on empty with five minutes remaining, this day I pushed as hard as I can, for as long as I can. By the 20-minute mark I was in oxygen debt yet again, but I had done well enough in the interval that mattered.

RGT told me it detected an FTP increase to 202 W.

Would I like to update it? the prompt said.

Oh, hell yes.

The power curve from this particular FTP test, courtesy of the Elevate plugin for Strava on the Chrome web browser. 95% of 213.6 W over 20 minutes equates to 202.92 W. RGT was being conservative.

I look back at this occurrence and chuckle it off as the rolling resistance of bicycle tires being a real thing, exacerbated by low inflation pressure. It was real enough to rob me of 8 W worth of FTP, even when I was using the 4iiii Precision crank-based power meter for all the testing.

Since then, I’ve continued training with my zones based off this shiny new 202 W FTP personal best. I don’t know how much farther I can push my power gains, as I’m not exactly young any more, but I’ll keep on working on it for as long as I can. As Greg LeMond famously said, “it never gets easier – you just get faster.”


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