It may seem impossible at first, but if you made it this far down the page, with your determination and the right prep you can probably finish an Ultra. For starters, check out Spartan’s curated training plans for Ultra newbies. Once you’ve completed a few Ultras successfully, like any other sport your focus should switch to improving upon your previous efforts.
Gear needs vary with terrain, weather, and if you’re in the mountains. Regardless, you’ll need more gear for the Ultra given the sheer distance. Most Ultra racers rely on a halfway-point drop bin. Consider waterproof layers, spare footwear and socks, sun protection, a hydration pack or vest, nutrition, a headlamp, a small medical kit, and other long haul items.