What a new durability study just proved

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Here is a problem you have probably lived. You test well. Your numbers look respectable on a fresh day. Then the race or the hard group ride gets long, the efforts start stacking up, and you are the one going backwards while riders you usually match ride away. On paper you belong with them. On the road you do not.

A new study put a number on exactly that gap. Researchers took 25 cross-country mountain bikers and tested them twice: once fresh, and once after a 140-minute fatigue protocol of repeated hard efforts. Each time they did three short repeated-effort tests, then later completed a race-style time trial. The question was simple. Which version of you predicts race performance better, the fresh one or the tired one?

The tired one won, and it was not close. The fatigued tests tracked race performance more tightly than the fresh tests across the board. One fatigued test alone explained about 89 per cent of the difference in race times. Your fresh test explained less. In other words, how you perform when you are already worked is a better read on your real ability than how you perform rested.

Then they split the field into the stronger and weaker performers, and the durability gap showed up clearly. After the same fatigue protocol, the stronger riders lost roughly 6 to 10 per cent of their power. The weaker riders lost roughly 15 to 20 per cent. Same fatigue, very different ability to hold power through it. Worth noting, the stronger riders were also fitter and leaner to begin with, so durability was not the only difference. But it added something the fresh numbers missed, and both groups reported feeling equally cooked. The stronger riders did not feel fresher. They just held their power anyway.

This is the whole idea we keep coming back to. Fitness is not only what you can do fresh. It is what you can still do when fatigue arrives. This study measured that directly, and it says the fade is the thing that separates riders.

What to do with this

If you race or ride hard finishes: stop judging yourself on fresh numbers. Put some of your key efforts late, after two or three hours, or deep into a long ride, and pay attention to what you can actually hold there. That late number is closer to your race self than any rested test.

If you ride big hours: you already accumulate the fatigue. The mistake is spending all of it riding steady. Add a few structured efforts deep into your long rides, when you are tired, because that is where durability is built rather than just endured.

If your time is capped: you cannot always ride long, but you can pre-fatigue. A solid endurance or tempo block followed by short hard efforts at the end exposes the fade and trains it, even in a session that fits a normal life.

Citation: Inoue A, Mateo-March M, Protzen G, Crivoi do Carmo E, Lattari E, Pereira Costa V, Bezerra da Silva E. Durability Predicts Performance in Olympic Cross-Country Mountain Biking: Evidence From Intermittent Tests Under Fatigue. Scandinavian Journal of Medicine & Science in Sports. 2026;36(6):e70324. doi:10.1111/sms.70324

On my mindA plateau in your routine comes before a plateau in your fitness

I have been thinking about plateaus, and I am increasingly convinced that a plateau in your routine comes before a plateau in your fitness.

The body adapts to stress. No new stress, no new adaptation. If you ride the same loops, at the same efforts, in the same order, week after week, you should not be surprised when progress stalls. That sameness is fine for holding onto fitness. It is not how you build more. To keep progressing you have to keep giving the body something it has not already solved, and sometimes that means rethinking more of the week than you would like.

It can even mean going backwards on purpose for a while to come forward later. I have used that with athletes more than once, dropping load or intensity deliberately so there is somewhere to climb back to. But you do not always need anything that dramatic. Often the fix is small. If you feel stuck, look hard at your routine before you blame your fitness, and change one or two rides in the week. See what that does. The plateau is frequently in the habit, not the legs.

Damian