In recent years, a controversy has developed between supporters of short and long format three-day events. Traditionally, three-day events had dressage, endurance, and show jumping. Endurance day consisted of 4 phases: A, B, C and D. Phases A and C were roads and tracks, with A being a medium-paced warm up to prepare the horse and rider for Phase B, a steeplechase format at an extremely fast pace over steeplechase-style fences. Phase C was a slow-paced cool down coming off of phase B, in preparation for the toughest and most demanding phase, D, or cross-country. Before embarking on phase D, in the "ten-minute box", horses had to be approved to continue by a vet, who monitored their temperature and heart rate, ensuring that the horse was sound and fit.