Ultra-running is a form of long-distance running that goes beyond the traditional marathon distance of 26.2 miles. Races can vary in length, often starting at 50 kilometers (about 31 miles) and extending to 100 miles or more. Ultra-runners often compete on trails, which adds an extra challenge due to varying terrain and elevation changes. Participants in ultra-running events, like the Western States Endurance Run or Badwater Ultramarathon, must train extensively to build endurance and mental toughness. Nutrition and hydration are crucial, as runners need to maintain their energy levels over many hours, sometimes even days, of continuous movement.