The first trailers were probably the gendarmes and the smugglers. There is moreover a trail named “the smuggler” in the North of France. The trails, Anglicism coming from trail running or running on trails, is a term adopted internationally to describe long-distance running races (or endurance), in a natural environment (mountain, desert, forest, plain...) with the minimum of cemented or paved road (which should not exceed 20% of the total distance). The terrain may vary (dirt roads, forest roads, single track trails....) and the course must be properly marked. The race is ideally, but not necessarily, semi-self-sufficiency or self-sufficiency (International Trail Running Association-ITRA). Like triathlon, trail races, which are already rather long, probably seemed bland to some runners, because the ultra-trails appeared quickly. It is about races of 50 or 100 miles or even 24 hours. Because the world of trail evolved rather quickly, the organizations trying to structure it are quite numerous, especially in the US, and their relationships sometimes less obvious. Thus, the" mountain trails, the trails and ultratrails are three disciplines which fall under the umbrella of the Long Distance Running (LDR)” and are managed by the Mountain Ultratrail Running Council which organize its competitions under the auspices of USATF (USA Track & Field). This organism is working in conjunction with the International