FTP: The Number You’re Chasing Wrong

By Ric Stern

FTP. It’s the number we’re all chasing, right? But what if I told you it shouldn’t be?

I know, if you read some of the online training articles you’ll see things like “FTP is wrong, you should be using critical power (CP).” But I mean something different to that.

Winding the clock back

Let’s go back to the beginning of the “power revolution”, around 1998/99. Dr Andrew Coggan came up with a way of capturing power data and measuring it against what you can maximally do for about an hour: Functional Threshold Power. It’s a brilliant concept. He then developed metrics that tie into FTP to measure strain and intensity. Seriously, it’s fantastic stuff. Without Dr Coggan’s work we’d be in a different place entirely.

Independently, and a few years earlier, I was looking at a different metric: maximal aerobic power (MAP), the best 60 seconds of a ramp test to exhaustion. I developed a concept that estimated FTP from a MAP test, along with a lot of other durations. (Technically what I wanted was to estimate the power that could be sustained for about an hour.)

Side note: in the UK, because we’re all bonkers, time trialing was and is hugely popular. We have TTs at 10 miles, 25, 50, 100, 12 hours and 24 hours. I wanted to estimate power values for all of those, as well as for road races and criteriums, from a single ramp test.

You can think of MAP as the power you produce at VO2max. Strictly speaking it captures both your aerobic and anaerobic capacity, which is actually what makes it so useful. It’s an integrated measure of your whole engine, not just one part of it. (Happy to explain the finer details for anyone who wants the full data-nerd version.)

Where “75% of MAP” came from

What I found, after testing a couple of hundred riders, everyone from people doing social group rides to elite World Champions riding the Tour de France, was that all but one fitted into a range: 72 to 77% of MAP gave you your ~1 hour power.

I used to write about this on several power newsgroups I belonged to in the late 90s and early 2000s. One day I got bored of writing “~1hr power/FTP is usually 72 to 77% of MAP” and just wrote “FTP is 75% of MAP.”

And somehow, that stuck. Zwift, Rouvy, MyWhoosh and other indoor training platforms all use it to estimate FTP.

The problem with chasing FTP alone

Here’s the thing FTP on its own can’t tell you.

Two riders can have exactly the same FTP and be completely different athletes underneath. One might have a high MAP and a low ratio: plenty of top-end, less endurance. The other a lower MAP but a high ratio: less headroom, but very efficient at using what they’ve got.

Their FTP is identical. What they need to train is the opposite of each other.

FTP alone can’t tell you which one you are. MAP can.

So what does this mean for you?

First, it gives you another number to improve and work towards. We’ve discussed how VO2max is important, and improving MAP will likely mean improving your efforts above FTP, which are generally shortish (several minutes or so). You know, like smashing up a short hill, or chasing riders down.

Importantly though, it also gives us a clue about how you may need to train.

If you’re training for an ultra-distance event, you want your FTP to be a high percentage of your MAP. So say you tested your MAP tomorrow (that’s the ramp test in Rouvy, Zwift and the rest) and then tested your FTP a few days later with a 20-minute TT, and it came out at FTP/MAP = ~71%, say 192W for the TT and 270W for the MAP. That ratio is below the typical range, which tells you your training should be designed to lift that 192W number.

On the other hand, say you ride criteriums and want to smash the final 500 meters with a huge effort. It’s likely you’ll want to increase the 270W MAP number more than the 192W. That way you’ve got more punch for lighting up your legs and crushing everyone else.

Of course it’s more nuanced than that in practice, but it gives you a starting point.

Putting it into practice

If you’re training yourself, these are the starting points I’d generally recommend looking at. You’d then fit your training around the hours you actually have available, the specific demands of your goal event, and your own strengths and weaknesses.

Of course, if you’re being coached, all of this is taken care of for you.

We’ve just released MAP: The Build, a personalized, structured four-week training block built from your own MAP and delivered straight into your TrainingPeaks calendar, ready to ride. It takes everything above into account, with minimal coach contact, for £25 per four weeks.

Have a look here →

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Ric Stern is founder of CycleCoach and has coached athletes to World Championship gold, Commonwealth medals, and Paralympic podiums across 29 years.