Traditional endurance training focused on V02 max, lactate threshold, and running economy. However, these metrics failed to predict race outcomes accurately. Athletes with lower scores often outperformed those with higher scores.

Researchers are now quantifying durability, or fatigue resistance, to understand these discrepancies. This factor may be the 'fourth pillar' of endurance performance. Durability explains why athletes with similar scores can have vastly different race results. Read more culture coverage.

Alex Hutchinson discusses the latest findings on fatigue resistance on The Shakeout Podcast. The podcast explores what durability entails and its implications for runners. Sign up for the Shakeout Run event on Oct 15. Related: Indigenous Runners Honored on Orange Shirt Day.

This original Runner World brief is based on reporting from Canadian Running. Visit the source for its complete reporting, context and any later corrections.