120% of FTP for 8 minutes outdoors - is that possible?

Went cycling outdoors today and PR’d up one of the local climbs.

The climb was around 90 minutes into the ride, I’d been doing a steady endurance pace and there were a couple of climbs before that - all of which is to say I didn’t hit the climb on totally fresh legs.

The climb is a 5.2% consistent gradient and typically takes me between 8 & 9 minutes to get up. I’m a heavier rider at around 2.8w/kg.

Today I PR’d the climb, which is great!

Looking at the numbers though, I effectively held 120% of my FTP for the whole 8 minutes. I’d dropped my cadence down to around 60 for the climb. I didn’t feel particularly destroyed at the top - rode the 60 minutes home over undulating roads at a stead endurance pace just fine.

Based on the VO2 max training I’ve done before, this seems like a long time to hold that power. One difference is that I aim for very high cadence in VO2 max training.

So what’s going on here? Is this just a case of the lower cadence allowing me to work at a higher power number for longer?

Any insights appreciated.

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Of course. It’s just a relative number.

Maybe you’ve done your FTP test indoors and you now benefit from better cooling and evaporation outdoors. You are also benefiting from better position in your bike allowing you to activate muscle groups and motor units more efficiently.
Maybe you even haven’t updated your FTP in a while and actually gotten fitter.

Altogether its a known phenomenon that outdoor FTP test numbers are often higher than indoor. So after all maybe you’ve only held 115% or 110%. The fact that you’re 2.8W/kg supports that more, as a few watts more will be a relatively high percentage of your FTP.

Do you want to post some absolute numbers of your FTP, power over the climb before and after?



Sure. I’m currently 80kg, ftp of 225. I held 271 over the climb for 8 minutes.

Last year when my fitness peaked, I did 117 % for 6:50 minutes with an average heart rate of 159 — and I felt as if I had plenty of gas left in the tank, I didn’t even need a breather. So is it possible? Yes, but you probably gotta train for it. At the time, I was doing the crit plan, which focusses on short power. And it delivered.

Regarding your cadence, I don’t think I can give you a simple answer here. Typically, at lower cadences you shift the burden from your cardiovascular system to your muscles. But of course, this is only true to a degree. Personally, I don’t like it too much when my cadence drops to 60 rpm, I prefer 70–85 rpm, but that’s just my preference. I also always stay seated rather than get out of the saddle. Purely personal preference, though.

What do you use to measure power indoors and out, the same power cranks or pedals?

Indoor is the trainer (4iiii fliiight). Outdoor I use assioma pedals.

Different bikes on trainer vs outdoor.

I have compared both before by using my outdoor bikes and pedals on the trainer and they seem reasonably close - 5-10 watts

If your FTP is correct (of which more shortly), 120% for 8 minutes is right at the upper limit of what should be possible: like a fully max, flat out, get off the bike and die effort*.

It doesn’t sound like that, so there’s a number of explanations:

  1. You’ve got fitter (so your FTP is actually higher than you think)
  2. Your previous FTP number was low, perhaps through tiredness, heat stress - there are loads of possibilities
  3. There is a marked disparity between your indoor and outdoor FTP.

What all these things have in common is the idea that you have 1 FTP number. In reality, that number is always contextual (how tired are you, how motivated are you, hydration etc etc) and is always subtly moving. Any test is also both contextual and anapproximation.

So what you now know is you can hold that power, at least outdoors.

Try it indoors and see what happens. Maybe also consider re-testing FTP, or simply bumping it up 5% and seeing how your workouts feel.

*the best I’ve ever managed, looking back at numbers, is 116% for 8 minutes, but (like you) it wasn’t a flat out 1 off effort.


This is a clear demonstration why professional cyclists and anybody wanting to reach their absolute peak, train outdoors.

Peak performances are virtually always achieved outdoors. This is for a million different reasons.

I personally recommend and enjoy indoor training. However, it’s absolutely paramount that you get outdoors and execute your key sessions under ideal outdoor conditions, when possible.

It’s both more fun and generally always results in better performance.

I have the luxury of time, so will never do intervals indoors if I can possibly avoid it. Anything above tempo I do outdoors.

Having tried threshold and V02Max indoors I rapidly learnt that it is almost impossible to provide adequate cooling, regardless of your setup.

This means your training, while convenient indoors, is nearly always sub optimal.

The surprising lesson, is that at low power, indoors riding is considerably more valuable than outdoors. Almost contrary to what many people think. This is particularly so for anyone living in cities.

The issue being, very few humans want to do long Z1/Z2 work indoors. For good reason.

Simple terrain based hill intervals have and likely always will be the ideal solution to peak performance.


Unless you live in flatland!!!

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I just did 126% for 5 minutes on a climb, I didn’t know I could do it until I tried. My lungs hurt for 2 days after it. I can repeat 120% power pretty well up to 4 minutes, but for 8 minutes I don’t know. You don’t know until you try.


Hmm… not sure about that.

I’ve experienced what the OP’s experienced. In my case, I did 125% FTP for 6 minutes to PR a Strava segment, but it was not repeatable and there was a massive anaerobic contribution.

Compare to this to some of TR’s workouts like 6x3min @ 120% or 9x3min at 118%, there’s no question that the structured workouts are more repeatable with longer Time in Zone.

You can certainly do these workouts outdoors if you have the available terrain nearby, but many people don’t.

Yes I used to be able to do 125-130% for 10 minutes when I focused more anaerobic stuff

This season I’ve done 117% of my ftp for 8 mins and 120% for 6 mins 30 seconds. So I would think it’s possible. My FTP is calculated from the same power duration curve on intervals.icu as well so it’s using the max numbers for fitting purposes


Just want to chime in that we’re discussing a VO2Max situation. High % over FTP, and durations in the minutes. These are by definition extremely aerobic. Max aerobic, in fact. While the anaerobic contribution in these efforts is, of course, not to be ignored, it is however not of significant concern, especially in these longer VO2Max intervals ~8-10mins.


Yes but I think as a one off effort you can get quite a big anaerobic contribution. Around this time I could do 210% for 2 min.

Perhaps I will just say I was highly trained at short efforts and not good at longer efforts.

A lot of this is going to depend what percentage of MAP your FTP falls at. For instance if your FTP falls at 70% of MAP, then holding 120% for 8 mins should be straight forward. If your FTP falls at 90% of MAP then it’s a different story.


Yes it is. Those are mainly aerobic - yes, but you have anaerobic contribution even with 20 min test (that’s why it can overestimate your real ftp). So if you have huge FRC, and low fractional utilization at FTP, the precentage will change significantly. The aerobic part will be main driver but anaerobic part is also a big factor. It all depends on your individual PdC. That’s why vo2 max work should be individualised and not done by percentage of FTP based on bell curve.

I rode a similar climb last year at 120% ftp for 8 min and I was feeling smashed. Your ftp is prob higher than when you last tested.

it is if your FTP is set 60%

Before I signed up for TR, I used my Garmin’s estimate. I had an 8 minute power 117% of my FTP. That was part of the data the Garmin used to create my estimate.

Since then, I haven’t retested 8 min power but that same PB is…

132% of my first TR estimate
122% of my current TR estimate

FWIW, my best 12 min power is 118% of my best TR FTP