Vernillo et al. 2016, an extreme mountain ultra-marathon decreases the cost of uphill locomotion

Field study in Frontiers in Physiology measuring locomotion economy before and after the Tor des Géants (about 330 km, +24,000 m). Despite severe fatigue, the net energy cost of uphill walking fell about 11.5% and of uphill running about 7%, with kinematics largely unchanged, suggesting prolonged repetitive climbing drives a specific economy adaptation. Small field sample; an observational signal that uphill-specific economy is trainable, consistent with the broader durability literature.