Tom Bell about TR statement that indoor and outdoor FTP is the same

Tom Bell busts the TR myth/cult that indoor and outdoor FTP is the same EVEN IF 95% people feels differently…


I must have missed this myth…:man_shrugging:

I think it is pretty well accepted that many people have a higher outside FTP than inside….motivation, cooling, inertia, etc all being factors.

ETA - this feels very click-baity and Bell is using TR as a target for said clicks. I also have no doubt that this thread will quickly morph into what the definition of FTP actually is.



My kinda snarky 5 min Friday read says:

  1. Mental
    Well, so that doesn’t mean it is or isn’t true, that means it might be true. It might also be true in reverse; perhaps some people can focus better indoors.

  2. Biomechanical
    Another difference comes down to the way resistance is applied throughout the pedal stroke. Older trainers (particularly wheel-on trainers) will apply 360 degree resistance. In other words, you’re pushing against something throughout the entire pedal revolution. In contrast, when you’re riding outside, there are resistance ‘dead-spots’, where your muscles are able to take a very short break from having to turn the cranks. Bertucci et al., (2012) showed that this difference in resistance (also known as ‘inertia’), resulted in different peddling dynamics, which helped explain some of the drop in economy indoors.

Aerodynamic loading outdoors doesn’t come in short bursts timed to your pedal strokes. And we’re just completely glossing over that you can choose a less inertially supported gear in ERG mode? GPLama’s video on erg mode gearing demonstrated this. On the flip side, again, this isn’t always even true outdoors: The amount of pedal intertia and power circle at 53/11 on a -3% down is much different than 34/25 at +8%. This is a major overlook of reality. Inconclusive + LOL.

  1. Overheating and dehydration
    And we all know there’s none of that outdoors. :face_with_diagonal_mouth:

I rate this article meh/10. There are good reasons to not use one number both indoor and out, but I feel like this massive conclusion isn’t as supported as they’re writing it to be.

Pick a number (or two) that works for your training and move on. :man_shrugging:


You’re a few weeks early, we already have a February thread bleating on about FTP.


We’ll just roll this one into May’s.


Here’s a blog post from Coach Chad;

A lot of athletes will report they have a lower FTP when they test indoors than when they test outdoors, and sometimes vice versa. There could be a number of reasons for this, but a good one to look to first is thermoregulation. About 75% of your body’s energy consumption when cycling goes to cooling, or maintaining your body’s temperature. When you’re outdoors this is better-achieved thanks to wind and sometimes temperature. But indoors, you’re reliant on a fan or another cooling mechanism to keep your body from having to work so hard to stay cool.

We could go on and on in this section and try to dissect every little variable that could lead to a difference in test results, but ultimately I think it’s better to end this post simply: Because there are less variables to consider, assessing your FTP inside will provide more sound data, i.e. accurate assessment results, than what you’ll get outside. What’s more, because there are so many variables and differences to consider between the two approaches, you simply cannot compare your test data from an outdoor test to your test data from an indoor test, and vice versa.

How does Tom Bell define FTP?

Click away…


My thoughts exactly. And I Literally just asked the question the other day. How do outdoor TR workouts impact FTP detection/Adaptive Training for indoor rides.

It’s not. Here is the title amongst recent posts:

However this thread has a click bait title.

Read the article. Very well written with references and opinions from working with a leading e-racing team.


It’s not click baity at all and the article is written very well. If you want click baity check trainerroads latest youtube headlines.


I find the High North articles quite balanced and thoughtful. This is why it’s good to have a range in mind if doing a workout outdoors. Don’t be a slave to a fixed absolute number if outdoors; find out where in that range you can work that day. Some days you may be at the top of the range, other days near the bottom.


100%. I find everything easier indoors. If anything I wonder if my indoor FTP is higher than my outdoor.


Me too, there is no way I could ever do the sweetspot/ threshold intervals i do on the trainer outdoors although outdoors i can reach higher NP but average power is generally lower outside

Would you please also share the link to where TR has a myth/cult that says indoor and outdoor FTP are the same? I’ve been a user for many years and can’t remember hearing that.


This is better than the constant “x thing from TR is trying to kill me (emoji)”. I hate those posts so much and honestly wish they were removed or replaced with less inflammatory titles.

This actually has information and not just anecdotes from users.


Ahh. I actually agree with what that article is saying. You don’t get stronger inside or outside, your body is still the same body, but there are other factors at play. This feels more like the “your ftp is different every day” philosophy.


I don’t have a dog in this fight as generally I find my ftp very close between indoors and out. But the article does seem to argue that due to the different conditions indoors and out, that means that your ftp is different. Isn’t the logical conclusion that every day has different conditions, and therefore everyday’s FTP is a special snowflake?

I guess the counter argument is that there is a small variance every day, and that is why we feel we have good days and bad, beyond just how much fatigue we are carrying.

In regards to all these issues, sometimes I wonder if as athletes we should be training (more often) as I did when I started - with only my Timex Ironman watch for a stopwatch, and then I got advanced and bought a heartrate monitor. You did your intervals by time and the feel-o-meter and you know what, I saw similar improvements as I do today. And I never really worried if my FTP was up or down today.






As a human being, we have one functional threshold power cycling because this is a description of our physiology. Not our environment.

Our ability to express it varies by environment.

It’s really not a myth, cult or anything but understanding what Coggan worked on.

On the flame-of-the-week scale of 0-Dylan Thomas, this thread ranks 0.3 for me.