What’s your real FTP?…AKA Fatigue Resistance

why stop there? Make all training 20 minutes or less! You can accomplish a lot in 20 minutes, including an FTP test. Yeah I had to bring it back to the thread topic… Bonus points, fatigue resistance at 20 minutes looks incredible! Average speed on Strava? KOMs? Training and riding for only 20 minutes is the real deal. Sprints in sixty, tempo in ten, sweet sixteen, the fast and the furious… I could go on and on but times a wasting, the world needs me to make a website and spread the word. Word.

Not sure what are you trying to say here, honestly. Didn’t try to offend you or your riding stile of choice, just to understand what is it all about. If I get bored spinning hours at a steady low tempo that doesn’t say anything about you, only about me.

I’m only half kidding. I was able to push to a really high peak of fitness by riding 20 minutes full gas on my morning commute, and then in the afternoon ride by how I felt. Which meant sometimes doing a single 30-60 minute hard interval over 75-90 minutes taking the long way home. And next thing you know I was doing ftp for over an hour and it felt awesome to ride so strong and repeatedly knock out hard efforts in my mid fifties with almost no prior experience. No idea if I could ever repeat that, but it worked once over 6 months. And I was a zombie at home and my night owl wife got pissed I was falling asleep at 8:30pm. Decided I like my wife more than my bike.

The boring statement makes it seem like you don’t want to understand or do it. But hey if you want me to write some more website copy, the ‘science’ is to work your slow twitch muscle fibers to make them stronger, and more fatigue resistant. And do it long enough to start recruiting fast twitch fibers and make them more aerobic, more like slow twitch. Which means its ok to toss in short 5-10 second sprints (neuromuscular and your 3rd energy system), but try and keep a lid on the amount of hard efforts that end up recruiting your fast twitch muscle fibers. Use your judgement, those hard digs downhill and uphill will delay what you are trying to do with the slow twitch muscles. So its at this point you need to figure out how to pace these, without going into a lab. I did them by heart rate, then got a power meter, and switched to doing them by power. Some swear by heart rate. Some swear by feeling.


I’ve been doing power tests after a few hundred TSS for the week and then after about 1000Kj for the ride for years now. I only do this doing big miles and low intensity though. Even when I start intensity, unless super flat or a horrible work week (no sleep) I don’t worry about tapering much at all.

Pre ride fueling with more protein seems seems important (for me) for better fatigue resistance. Traditional carbs on the bike consuming something every 30 minutes.

For KJ figures, it’s better to normalize for weight. 40-50 kj per KG is ok. But even then not all KJ’s are created equal. Individual customization given riders profile and objectives seems mandatory.

Some metrics benefit from normalizing by weight, to make a comparison between riders.

I’m still trying to make sense of normalizing kJ work. What is your thinking?

Off the cuff, in terms of fatigue resistance isn’t kJ work directly related to target event duration and FTP? Taking into account stuff like road racing in a peloton will reduce kJ work at the end of a 3 or 5 or 7 hour race, as compared to training.

Haven’t spent time thinking much about it, just a few off-the-cuff random thoughts.

Just trying to give realistic KJ targets vis a vis time to small riders. I know a fair amount of 52kg guys and of course girls.

Which I believe comes back to your ftp, as smaller elites may have a 350-400W ftp and be the same weight as my sister with a 100W ftp.

100W FTP 150W FTP 200W FTP 250W FTP 300W FTP 350W FTP 400W FTP
kJ per hour at steady 60% FTP 216 kJ/hour 324 kJ/hr 432 kJ/hr 540 kJ/hr 648 kJ/hr 756 kJ/hr 864 kJ/hr

Which then makes me think about the metabolic cost of having a higher FTP. Lets assume 120g/hr is maximum carbs you can consume and use, that’s 500 calories per hour, enough to balance out 500 kJ of work per hour. Assuming enough you are eating enough carbs at the table, fueling workouts at 120g/hr might be way too much for someone with a 150W FTP but absolutely essential at and above a 300W FTP.

I think raw watts are more appropriate here, and when talking about comparing riders on flat windy races and flat TTs.

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I disagree here. Specifically with regards to time. Look at a 50kg rider that has a 200w ftp….4 w/kg. How long would it take this rider to do 2500kg of endurance? compare that with the larger athlete….

regardless of W/kg, it would take a 200W ftp rider doing steady 60% IF (lower endurance, where average power = normalized power) about 3.5 5.8 hours to do 2500kJ of work.

The W/kg simply doesn’t matter.

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This is wrong

Power = 200 * 0.6 = 120

2500 = (120 * Seconds)/1000

Seconds/3600 = Time = 5.78h

yes, thx, fixed it above, was juggling too many numbers at work.

Returning to my point, the amount of kJ work is independent of your W/kg. Calculating kJ work comes down to average power, which is dependent on your raw FTP.

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I agree with both of your points, now throw in fat/carb utilization differences for different ftps/vo2max as well as size…then glycogen storage capacity and weve got ourselves a real conundrum

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my pragmatic approach, mentioned above, is you can easily work around that by doing field testing and pulling data from power curve.

Along the lines of this thread, one approach I used this year was to do a ramp test followed by some rest then an all out 12 or 20 min.

When I do it again, I’m going TT style like I did in 2017. And start with fatigue over an hour, like the top-line here:

is a single 71-minute effort at 269W, which dropped only 2 watts versus 60-min at 271W. And still at 260W at 90-minutes. The best 30 minutes was the last 30 minutes of that 71-min effort, a nice negative split.

The 2 hour power for that one was 241. That’s as good as I was able to do back then. I really don’t have any hard 3 hour efforts from that year.

That’s my idea, keep it simple, keep it focused on 1 hour vs 2 hour vs 3 hour portion of the power curve (I’m interested in long climbs and raising ftp for Wed worlds), and keep it inline with actual efforts that can be field tested outside on flats into a headwind, or on long climbs.

In other words, work on lifting up the tail of the power curve:


make the actual power (yellow) and modeled curve (red) as flat for as long as possible.