At a loss for where to start? Here’s a guide to the most popular obstacle runs.

Tough Mudder

Perhaps the most famous of obstacle runs, the Tough Mudder series features a ten to twelve-mile course and emphasizes teamwork, cooperation, and persistence instead of focusing on who completes the course the fastest.

“Each Tough Mudder has over 20 obstacles, which range from the expected (huge swaths of mud, walls to climb) to the creative and eccentric (10,000 volt electric shocks, plunges into ice-cold water).”

Because of the length of the course and the number of obstacles, a Tough Mudder is guaranteed to take you several hours to finish.

Most people run Tough Mudders as part of a team, and many obstacles require teamwork to overcome. The events are massive: each Tough Mudder can have over ten thousand participants. The number of runners combined with the size of the course means that Tough Mudder events are usually held outside major urban areas, and are often split over two days. The event starts in waves to control traffic on the course.

Since it’s not a formal race with winners and loser, skipping obstacles is totally up to you. If diving through a field of electrified wires isn’t your cup of tea, that’s no problem.

If you’re looking for a challenge from fellow participants as well as the course itself, the Spartan Race might be just what you need. Make no mistake; the focus of these events is competition. All Spartan Races are chip-timed like a marathon, so you’ll be able to see how you stack up against the rest of the field. If you skip an obstacle, you’re forced to do 30 penalty burpees.

“The event comes in several variants, from a three-mile, 20-obstacle “sprint” to a marathon-distance “ultra beast” that includes over 60 obstacles.”

The course is more strength-oriented too—competitors in a Spartan Race often find themselves climbing ropes, carrying heavy stones, and throwing javelins.

As a result, Spartan Race encourages you to train hard for the event. The race’s website includes training tips and even a “workout of the day” to prepare you for the race. Like with the Warrior Dash, the top competitors can qualify for the Spartan Race World Championships. If you were hoping for an easier route to fame and glory, think again—last year’s Spartan Race World Champion is a special forces soldier in the Army National Guard.

Does twelve miles sound a bit too far? A Warrior Dash might be a better place to start, as all events are only five kilometers (3.1 mi) long and take most people less than an hour to finish. Each event boasts a dozen obstacles, and the obstacles are in line with what you might expect on an obstacle course.

“There are wall climbs, barbed wire fence crawls, cargo nets, and yes, plenty of mud. Though there’s no electrical wires, do be ready to leap over a flaming log!”

None of the obstacles require teamwork to overcome, but over 90% of people register as a team.

Unlike Tough Mudder, the Warrior Dash does have a competitive wave. Anyone can register for the competitive wave. Though the event is untimed, the top finishers win a free entry to the annual Warrior Dash World Championships, which features an impressive prize pool. Good luck winning any of it, though—the top two finishers for both men and women last year were professional distance runners!