One of the main reasons for a DNF in an ultra is nausea and vomiting (23% of DNFs at the 2009 WSER were for this reason). Even among those that finished, up to 40% of the Western States field [...]
Walking is typically seen as the soft option in running races, however in an ultra its often the smart option. In a hilly race even the elites walk, the difference between them and the back of [...]