Endurance is a long-distance competition against the clock testing the speed and endurance of a horse and challenging the rider over their effective use of pace, thorough knowledge of their horse’s capabilities and ability to cross all kinds of terrain. Although the rides are timed, the emphasis is on finishing in good condition rather than coming in first. Endurance started as a sport in the United States, where the US cavalry tested its horses on a five-day, 300-mile (483km) ride, with each horse carrying over 200lbs (91kg). It did not become a competitive sport until the 1950s, when Wendell Robie traced the Pony Express route from Nevada to California in under 24 hours. Each rider must safely manage the stamina and fitness of their horse and each course is divided into phases – in principle at least every 40km – with a compulsory halt for a veterinary inspection, or ‘vet gate’, after each. Each horse must be presented for inspection within a set time of reaching each ‘vet gate’, which determines whether it is fit to continue. Arabian horses dominate the Endurance discipline though the most successful rider to date is Spain’s Maria Alvarez Ponton on her French-born gelding Nobby. The premier Endurance rides are the FEI World Equestrian Games™, staged every four years in the middle of the Olympic cycle; the FEI World Endurance Championships, held in every Olympic year; and the biannual FEI European Endurance Championships.