Infiny'flamme Trail - Luynes is a spring trail race held in Luynes, Touraine, utilizing a 6.6 km backyard-ultra loop. It is organized by the Amicale des sapeurs-pompiers de Ouest Agglo, the local firefighters' association. Rather than a single fixed race, participants select from options of two timed loops, three timed loops, or the Infini'flamme format, where the race concludes when only one runner remains to start each hour.
The procedure is straightforward: complete the loop, await the next hourly start, and continue; missing the start or withdrawing ends your participation. The two-loop choice is available for ages 16 and older, covering 13.2 km with 122 m elevation gain. The three-loop option begins at age 18, spanning approximately 18.8 km with 183 m elevation gain. The complete Infini'flamme is intended for runners aged 20 and above, with no set finish time as the final competitor determines the outcome. This format originates from the Backyard Ultra concept, established in the United States in the early 2010s, emphasizing consistent pacing and perseverance alongside speed.