Running stands out from other endurance sports because a weekly volume of 10 hours is sufficient to reach the top 0.1% of practitioners, due to the physical limit imposed by impacts which prevents increasing volume indefinitely.

noli's read

The idea that running has a stricter physiological limit due to joint and muscular impact is a classic concept in sports physiology, often discussed in literature on training load management (observational studies on overtraining syndrome). While the 10-hour volume is an interesting indicative figure, framing it as a universal threshold for the 'top 0.1%' is a simplification: world-class elites often accumulate more volume, frequently distributed between running and cross-training to circumvent these mechanical constraints. The notion that running 'is unforgiving' is supported by research on running-related injuries (RCTs and cohort studies), confirming that increasing volume too quickly is the primary risk factor. However, asserting that it is the *only* sport allowing such performance with this volume is a subjective view, as other sports with high technical or physiological demands present different barriers. The statement is therefore a relevant observation on the specific mechanical constraints of the discipline, while being a high estimate regarding elite performance.

the sources

No named source held this one up — that absence is part of the verdict.