Bodyweight exercises are often bottom of the list when it comes to getting in shape for a Spartan race. But the burpee? Well, that’s a different beast.

In fact, the burpee has become synonymous with Spartan, and it's best you know why before you show up at the course.

Physiologist Royal H. Burpee had modest expectations for the exercise he created. In his 1940 book, “Seven Quickly Administered Tests of Physical Activity,” Burpee wrote about a four-count move that could test the state of a person’s everyday fitness. The original exercise:

1. Squat with both hands on the floor in front of you.
2. Kick your feet back behind you so you’re in plank position.
3. Jump your feet forward again.
4. Return to standing position.

The exercise has since evolved into a six-count torture device with two key additions: dropping to a pushup after the plank and finishing with a forceful jump up into the air, arms straight above your head.

It’s the quick progression through these different moves that make the burpee so effective, says Caitlin Bailey, a senior personal trainer and Spartan SGX Coach at New York City–based PhilanthroFIT. “Performing the movements in rapid succession increases both your cardiovascular and muscular endurance,” she says. “This improves your anaerobic capacity, which is the body’s ability to produce energy without using oxygen.” That translates to better performance, particularly when you’re exhausted.

For obstacle course racing athletes, intent on claiming a Spartan medal, there’s another good reason to bone up on the burpee. It’s a crucial component of the event itself.

“If you fail an obstacle you must perform 30 burpees before continuing,” explains Bailey, who is a multiple top 10 female Spartan Race finisher. “The more you train, the easier those 30 burpees will feel and the faster you can complete them and get back into the race. Though you always want to race with the goal of not having to do any burpees, train as if you’ll be doing the 30 for almost every obstacle.”

(To do a proper race burpee, your chest must hit ground. Then, stand with full hip extension and jump straight up, hands at least above your ears. Both feet must leave the ground and you must reach full hip extension—body straight and perpendicular to the ground.)

So, for Spartan and burpee newbies, how would Bailey suggest bringing the movement into a workout? “Start small by performing five burpees in a row and then taking a break,” she says. “Do this for six sets so that you get 30 total.” From there, over a period of days and weeks, progress to 30 nonstop.

There are a number of burpee variations, but Bailey—a true Spartan at heart—advises that you go all in or go home. How so? By integrating a heavy medicine ball into the move. “During the race, not only will you be doing many burpees but you will also be picking up and carrying heavy objects. So why not combine the two into one butt-kicking exercise?”

When you’re ready to give it a try, here’s what to do:

1. Plant your hands on the ground and jump your feet back into a plank.
2. Perform a chest-to-ground push up and then jump your feet back in toward your hands.
3. Once your feet are planted firmly, engage your abdominals and use your legs to stand up while lifting a 20- to 50-pound medicine ball. Take a few steps with the weight.
4. Drop the ball and repeat.

When you can do 30 of these nonstop, you’re ready to race.

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