As recently as 7 years ago, obstacle races were relatively unknown, having just a small, cult following comprised mainly of large men who like to combine tire-flipping with intense cardio activity. In the past few years, though, their popularity has sky-rocketed as the running and cross-fit communities have come together to put on hundreds of races such as Tough Mudders, Warrior Dashes and Spartan Races.
The appeal of these races is self-evident as they combine the challenge of distance running with the exhilaration jumping over fire, charging through a mud pit, army-crawling under barbed wire, and blitzing through a field of electric wires (that last one is genuinely weird).
But how does one train for an event such as this? Short of creating a custom obstacle course in your own backyard, it seems hard to prepare for these races. Actually, the training for an obstacle race is not that different from training for any other race.
First, it is worth noting that each of these races is a different distance and contains a different number of obstacles. The standard distance for a Tough Mudder, for example, is 10-12 miles with around 20 obstacles. There are also half Tough Mudders, which are 5 miles with 13 obstacles, as well as 5k Tough Mudders, 3 miles with 10 obstacles. There is even a 24-hour event, called World's Toughest Mudder, where athletes attempt to complete a 5-mile obstacle course as many times as possible.
For each of these events, the majority of your time will be spent running, so training to improve your running fitness is most important. One of the keys to being successful at an obstacle race is being able to stop running, complete an entirely separate activity, then get back to running.
To become accustomed to this style of exercise, one should complete circuit training workouts that combine running with different strength building exercises. Runner's World put out an article with a great example of a circuit workout here. Also, being sure to practice running on trails is imperative, as you will often be racing on uneven terrain. If you do not have easy access to trails, head to a local park and complete your circuit workout on grass.
Even though running is the majority of most obstacle races, the obstacles can still provide a bit of challenge and being able to get through them quickly will make the race more enjoyable. Since it is impractical for most runners to find or build an obstacle course of their own on which to train, the best way to prepare for obstacles is to be a well-rounded, strong athlete.
Basically, this means adding a core- and strength-building routine into your running schedule. If you choose to utilize circuit workouts, you are already well on your way to getting stronger and, thus, better at obstacle races. If you don't like the idea of circuit training, you can always hit up the old gym.
Body weight exercises such as push-ups, pull-ups and squats are often going to provide you all the strength you need, though if you like to pump iron, more power to you. Just make sure that you are building functional strength rather than just working the glory muscles.
Regardless of how you train for an obstacle race, make sure that you have fun on race day. That is what it's all about!