paywall

I'm not in this space, on either the athlete or the biomedical side - but it sounds like a "more is better" running mindset and mythos is colliding with the biological realities of human bodies which either (1) Were not carefully designed for this kind of duty cycle, or (2) Have accumulated quite a few deleterious mutations in the generations since that design, resulting in frequent operational failures at well below the hoped-for spec.

Might anyone know if indigenous groups such as the https://en.wikipedia.org/wiki/Rar%C3%A1muri - where extreme distance running seems part of their traditional culture - have been studied in this regard?

I wonder if this is due to a lower rate of coaching. I don’t have a ton of first hand knowledge but most other endurance sports the athletes usually come up through well organized teams. Maybe the lack of organization (which is great for other reasons) leads to less coaching and therefore missing someone to tell you to rest and recover before you go over the edge.

Nils van der Poel was* a long distance speed skater who set impressive records and wrote about his training regime. His book is https://www.howtoskate.se/. He trained ambitiously for 3 years, won Olympic gold medals and retired! He followed a very analytically minded path and avoided overtraining.

See also brief overview article about him:

https://runningmagazine.ca/sections/training/olympic-speed-s...

(*) He changed his name to be a more common name so using past tense seemed humorously appropriate.

"Mysterious"

"Overtraining syndrome"

I don't see why it's so mysterious, fatigue accumulates until something tips you over the limit