Deep Fitness: how to train it?

A term I’ve heard tossed around when it comes to pros and experienced riders describing an ability to perform for long periods of time, under high amounts of fatigue and/or multiple days on end. Some people might call this a “long term base” or another name but the idea is the same.
It it isn’t not quite as easily quantified as, for example, FTP [W/Kg] which is already a good gauge of somebody’s fitness. The first step to training something is quantifying it. there are many metrics that try to grasp the essence of deep fitness such as “tired 20” (20min power after 2000kJ of work), TTE (time to exhaustion: continuous time able to spend at FTP), FRC (functional reserve capacity) ect…
The question remains: these metrics become harder to conceptualize as the list goes on, we know they are the result of having desirable traits, so how to train them? Or can they even be trained for specifically? (maybe they are just the results of training and racing at a high level for years?)
Cycling tradition would have you believe that “piles of miles” will make you a “better cyclist”, modern wisdom would conclude that on a “time budget” TrainerRoad has it all figured out.

If you are willing to put in the work, what is the best way to do so to achieve this?

You are looking for the term “fatigue resistance” which is similar to what it sounds like, i.e. your ability to minimize the gap in your max power for a duration and your max power for a duration after a certain amount of work.

TTE, FRC, etc aren’t necessarily harder to conceptualize, they are just more descriptive and specific than FTP.

They may or may not be desirable, given you are limited by the amount of total work you can recover and adapt from.


Achieve what specifically? Fatigue resistance? Increased TTE? Increased FRC?

Instead of giving you answers to those, here is what I’d encourage you to do:

#1. Figure out the demands of your event, or the demands required to win in a set of likely scenarios
#2. Benchmark yourself against those scenarios
#3. Identify the deficiencies
#4. Analyze the tradeoffs to cover those deficiencies and decide on a plan

All of the terms you mentioned are tools in a toolkit, but if you don’t have a baseline understanding of what you are looking to accomplish, chasing specificty isn’t likely to yield the result you want.


The reason pros are able to put out high power after multiple hours of riding is they have preserved their glycogen stores by utilizing fat earlier in the race.

This is where the concept of FatMax comes into play. Training fat metabolism is something that requires longer duration rides at lower intensities. A higher FTP also helps. But I don’t think is sufficient.

Worth reading thru this, and in particular the section on fat vs carbs.


It’s not always about pushing your power up at a given point on your power curve. You might want to also consider extending the power curve to the right at said given point. For example, let’s say you’re doing 2x20 at 90% FTP, instead of continually raising the power because it’s becoming boring or easy, extend the time (i.e., 2x25, 3x20, 2x30, etc…).

Another example, how long can you ride at 85% FTP? Work on extending that out to 2-3hrs.

There is no best way to do this. There are some fundamental concepts, but so many different approaches which will all get your from A -> B. If there is one thing that is common to all of the approaches, it would have to be consistency, showing up day after day and putting in the work.


I think both are correct. To achieve peak fitness you need piles of miles (with smiles I might add) and structured training to keep giving you the necessary training stimulus