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WHAT IS FTP AND WHY DOES IT MATTER?

By Anthony WalshRoadman CyclingUpdated

WHO THIS IS FOR

IS THIS YOU?

The rider who just bought a power meter

You keep seeing FTP referenced everywhere and want to understand what it actually is before testing.

The rider whose zones feel off

Your easy rides feel hard and your intervals feel easy — a sign your FTP anchor is wrong.

THE ROADMAN VIEW

The Roadman view

Here's the thing nobody explains clearly when you first hear the term: FTP is not a mystical fitness score. It is one plain physical fact about you — the power you can hold for about an hour before you fall apart. That's it. Everything else in power-based training is built on top of that single number. When Anthony first started training with power, the penny dropped the moment he stopped thinking of FTP as a leaderboard stat and started treating it as a calibration tool. Get it right and the whole training system clicks into place.

The reason it matters so much is reach. Every zone you train in is a percentage of FTP. Your easy zone 2 is 56–75% of it. Your threshold intervals are 91–105% of it. Your VO2max work sits above it. So if your FTP is set 15 watts too high, every single one of those sessions runs slightly too hard, and you spend months wondering why you're tired and not improving. If it's set too low, your hard days aren't actually hard. The number is the foundation. A cracked foundation cracks everything above it.

What FTP physiologically approximates is your lactate threshold — the intensity above which your body produces lactate faster than it can clear it. Alex Welburn, the physiologist Anthony had on to talk about the metrics Pogačar's team actually uses, made the point that FTP is a useful field proxy for that threshold, not a perfect lab measurement. You don't need a lab. You need an honest test, a consistent protocol, and the discipline to retest as you get fitter. That's the whole game.

EXPERT EVIDENCE

WHAT THE EXPERTS SAY

  • Alex WelburnCycling coach and physiologist; PhD researcher at Loughborough University on critical power and W'

    FTP is best understood as a practical field estimate of the metabolic threshold — the boundary between sustainable aerobic effort and the rapidly-fatiguing zone above it. It is not a perfect physiological marker, but as a reference for setting training zones it is the most actionable number an amateur can build their week around.

    Hear it: Why Your CTL Is Wrong | Roadman Cycling Podcast
  • Joe FrielAuthor of The Cyclist's Training Bible; co-founder of TrainingPeaks

    FTP functions as the organising principle of structured power training. Every zone is a percentage of it, every interval target is derived from it, and progress is tracked against it. The discipline that matters is keeping it current — a stale FTP quietly mis-calibrates an entire training block.

    Hear it: Joe Friel's Cycling Training Plan Structure | Roadman Cycling

PRACTICAL APPLICATION

DO THIS WEEK

  1. Establish your FTP with a single repeatable test

    Pick one protocol — a 20-minute test or a ramp test — and run it rested. That first number becomes your baseline. Don't agonise over a few watts; you need a starting anchor, and you'll refine it every block.

  2. Calculate your zones from it immediately

    Feed your FTP into the FTP Zone Calculator. Zone 2 = 56–75%, threshold (zone 4) = 91–105%, VO2max (zone 5) = 106–120%. These watt bands are what actually drive your training, not the FTP figure on its own.

  3. Treat W/kg as the companion number

    Divide your FTP by your body weight in kilograms. A 250 W rider at 75 kg is 3.3 W/kg. FTP in watts governs flat-road speed; W/kg governs climbing. Track both so you know which lever to pull.

COMMON MISTAKES

WHAT CYCLISTS GET WRONG

  • MISTAKETreating FTP as a fixed personal score rather than a moving training input.

    FIXFTP changes with fitness, fatigue, heat and form. Retest every 6–8 weeks and update your zones — the number is meant to move.

  • MISTAKEComparing your FTP in raw watts to other riders.

    FIXConvert to W/kg before any comparison. Raw watts without body weight tells you almost nothing about relative fitness.

  • MISTAKESetting FTP high to feel good, then training to inflated zones.

    FIXAn honest FTP makes your easy days easy and your hard days hard. An inflated one turns every session into grey-zone fatigue. Test honestly.

FAQ

FREQUENTLY ASKED QUESTIONS

Is FTP the same as my one-hour power?
Almost. FTP is defined as the power you can hold for roughly 60 minutes. In practice most riders test over 20 minutes and take 95% of that figure, because a true all-out 60-minute test is brutal and rarely repeatable. The 20-minute proxy is close enough for setting zones.
What does FTP stand for?
Functional threshold power. 'Functional' because it's a usable field measure rather than a lab value, 'threshold' because it sits near your lactate threshold, and 'power' because it's measured in watts. The term was popularised by Andrew Coggan and Hunter Allen.
Do I need a power meter to have an FTP?
To measure it precisely, yes — a power meter or smart trainer. You can estimate a rough equivalent using heart rate (threshold HR is about 90–95% of max) or RPE, but those methods are noisier and less reliable for tracking small changes over time.
Is a higher FTP always better?
For flat-road and time-trial speed, raw FTP is decisive. For climbing and head-to-head racing, what matters is FTP relative to body weight (W/kg). A higher FTP helps everywhere, but it's only half the picture — weight is the other half.
How is FTP different from VO2max?
VO2max is the maximum rate your body can use oxygen — a ceiling on your aerobic engine. FTP is the sustainable power you can hold near your lactate threshold, which sits below VO2max. You can raise FTP toward your VO2max ceiling with training; raising the ceiling itself is harder.
Does FTP matter for casual riders who don't race?
Only if you train with structure. If you ride purely for enjoyment with no interval work, FTP is optional. But the moment you want to train efficiently — to get faster in limited hours — FTP is the number that lets you target your sessions instead of guessing.

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