Cool, have you done other Ultras? How would you compare 50k to a marathon?
I've done 3 marathons, 2 50Ks and a 12 hour overnight run (45 miles on difficult terrain).
The difference I've seen is that marathons tend to be pretty flat road races that you plan to run straight through (except for pauses at water stops), while ultras usually have steeper hills and tougher terrain that will force some walks. I don't find that I have to train much harder for a 50K, but I do make sure I spend a lot of time on trails.
There's a lot less focus on time in ultras. While you might run a tougher marathon course 5-10 minutes slower than a fast one, the difference between my 50Ks was over an hour, and I ran both pretty well. Some of the difference was due to the first one being at least 3 miles too long, which is not uncommon with ultras. Ultras are generally more laid-back than marathons. Some marathoners scoff at the slower times and the amount of walking done in ultras, but if you can get them to try a rocky course they'll learn respect. I like both races but prefer the trails. In my opinion the varied terrain reduces the repetitive stress injuries you get from road running.
You also have to learn to handle food in ultras since you'll be out there longer, whereas you can just get by with water and gatorade-like drinks and maybe a gel shot (gu or Clif Shot) or two in a marathon. Aid stations are a smorgasbord or salts, sweets, carbs, etc. Your body craves what you need. Once you're in shape for a 100 miler, one of the big challenges is whether you can keep down food to keep your calorie intake up. Another is to balance electrolytes. That's important for marathoners too, but when you're out for a much longer time and often alone, it's critical. Didn't Patton say "an army travels on it's stomach"? That's true for an ultrarunner too.
For night running, or probably cycling too, many of us prefer green LED flashlights over white. It gives a lot better depth perception.
. Good luck to all the runners out there in 2008!
