IAU 100 km World Championships

This is the global championship for the classic 100 km road distance. National federations select the elite field, while the accompanying masters championship gives experienced age-group runners a route into the same race setting. The format rewards even pacing and efficient crew work more than tactical trail skills.

The championship uses a nearly flat paved circuit in Ames. The opening loop is 4.8 km, followed by nineteen 5 km laps and short transition sections to complete 100 km. The compact layout makes splits and support easy to follow, but it magnifies small pacing errors across repeated turns.

September in Galicia can be mild and damp. Cool morning air may suit a fast start, while humidity, showers, and a warmer afternoon can make late-race fueling and temperature control more demanding.