Durability
This idea has been showing up more often in the scientific community — a large volume of papers since 2020 — because we needed a way to explain why riders with very similar relative power and physiology (VO2max, MMP) can have such different results in the same race, in the same conditions.
Durability was defined as the onset and the size of the drop in physiological characteristics during prolonged exercise (Maunder et al., 2021).
The thought itself is not new. Experienced coaches and riders already know that to race, you have to limit that drop after long efforts — beyond 3 hours, or beyond about 35 kJ/kg.
That is why this parameter matters as a performance indicator. Without it we may not be collecting everything we need.
You can have two athletes with the same 5-minute MMP and the same body mass. If, after 35 kJ/kg, one of them loses more than 3% more of that capacity than the other, the race tilts towards the rider who held more power.
We still need more research on how to train and measure this reliably. Until then, ignoring it means leaving out part of what decides the race.