The USOL Trail Challenge takes place in early April in Vaugneray, located in the Rhône department west of Lyon. The event focuses on short, intense formats instead of a single traditional trail distance. It features a 12-hour challenge using a repeating loop and a solo uphill time-trial race. Previous event details have also noted a 4.3 km road race for teams of two, indicating a preference for unconventional formats and collaborative efforts over standard trail running.
The 12-hour race allows participants, running solo or in relay teams, to complete as many laps as possible on a loop measuring approximately 6.8 km with around 322 m of elevation gain per lap. The uphill time trial is a 4.5 km climb with 360 m of elevation gain, conducted in two pursuit-style heats. Participant numbers are capped to maintain a small, family-friendly atmosphere, and the event is relatively new, having been held only a few times.