82. HOW TO TRAIN DURABILITY?

Photo by Stefan Scheepmaker on Unsplash

In the previous KisW Research Notes we saw some studies on the durability topic.

Here is a summary:

• Definition of Durability

  The ability to decrease as less as possible physiological parameters and performance during prolonged exercise (at least ~3 hours). It can be named also ‘fatigue resistance’ or ‘fatigue resilience’.

• Physiological Mechanisms Determining Durability:

  Durability doesn’t seem to be related to traditional physiological endurance marker like VO2max and threshold’s power output. In other words, having a higher VO2max or FTP doesn’t necessarily mean to have a higher durability. So, we can consider this capacity as an additional independent parameter determining endurance performance. (1) On the other hand, one of the physiological determinant of durability is preserving carbs availability and glycogen levels during prolonged exercise. (2) However, a recent study reported that, in continental level cyclists. when large amounts of carbs are ingested during exercise (100 g/h, a scenario similar to nowadays cycling races) fat oxidation levels during exercise were not related to durability. (3) This can suggest as glycogen depletion and so fat oxidation capacity is only one of the possible physiological determinant of durability and the higher and higher intake of carbs during race are moving the place of durability, at least in part, elsewhere. Where? We don’t know yet but it is likely that it can be:

  • muscle /soft tissues damage: even if it is less compared to other sports with more eccentric contractions like running, some level of muscle damage has been reported even during prolonged cycling;

  • general body inflammation;

  • central fatigue: central nervous system fatigue (brain and spinal cord) that leads to the inability to proper recruit muscles to produce watts;

• How durability can be tested?

  There are 3 ways:

  1. Standardized test (gold standard), that is performing a specific test in a fresh state and then repeat it after a ‘fatiguing’ protocol. When using this method, the durability score is the % decrease in the performance marker between fresh and fatigued state.

  2. Record Power Outputs after a certain energy expenditure (kilojoules) However, we should consider that just using a kilojoules benchmark (e.g. 3000kjs) can be misleading as the performance decrease during prolonged exercise depends also on the intensity and duration of the ride and not only on the energy expenditure.

  3. Power-Heart Rate Decoupling

  Higher the heart rate drift during the second ride to produce a certain power output, lower the durability. Lower the heart rate drift during the second part of the ride to produce a certain power output, superior the durability.

  To learn more about these testing methods you can refer here.

So, on the durability topic we have the definition, some physiological underpinnings and testing methods. What about the best training strategies to improve durability?

How durability might be trained?

A review by Professor Andrew Jones (the scientific director of Eliud Kipchoge’s ‘Breaking Two’ historical marathon record sponsored by Nike) and Brett Kirby (University of Exeter, UK) published in 2025 on Scandinavian Journal of Medicine & Science in Sports tried to answer this question.

Please, note that this is a preliminary work as durability is a relatively new topic in sport science. So, as the original title of the review indicates (Physiological Resilience: What Is It and How Might It Be Trained?), the training strategies outlined are ‘just’ hypothesis supported by some preliminary data (but still quite interesting), while more studies in the future will help us to understand more on the topic.

Have a good read of our summary!

Image from Jones and Kirby 2025. (4)

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1. DURABILITY IS A TRAINABLE CHARACTERISTIC

First: durability is a trainable characteristics and not only a genetic trait. This is the starting point, so that we are sure that it makes sense to speak about training strategies to improve durability. This information rises from the fact that trained people have superior durability compared to untrained people. For example, in 2024 Unhjem (Nord University, Bodø, Norway) reported that, after 1h of running in zone 3 (in a 5/7 zones model), ‘active’ adults increased more oxygen cost and reduce more VO2max when compared to endurance trained runners. So, given that durability is trainable, we can proceed to see how it might be trained.

2. FOR THE NEWBIERS: SIMPLY DOING ANY TIPE OF ENDURANCE TRAINING IMPROVES DURABILITY

It is the same as for improving VO2max/Thresholds/FTP/critical power. If you are not already (well) trained, everything you will do at the beginning will improve your durability regardless of the details of the training performed (high volume vs high intensity or short high intensity intervals vs long high intensity intervals, etc. …). For example, a study published by the Finnish group led by Matomäki and Colleagues (University of Jyväskylä) reported a similar improvement in durability after 4 weeks of extensive low‐intensity training vs much lower volume high‐intensity training in sedentary/recreationally active participants. (5)

3. BEST TRAINING STRATEGIES TO IMPROVE DURABILITY

While for the newbiers everything works, here some more suggestions from data and anectodal evidence from world-class athletes that can help to boost durability in already trained endurance athletes.