If you don’t attempt an obstacle, you can’t climb over it.

It’s basic logic, but it’s also at the foundation of the training that strength coach and obstacle course veteran Todd Cambio recommends to rookies who hesitate to sign up for their first obstacle course race (OCR).

“Sign up. Forget worrying that you can’t do it. You’ll figure out the rest,” Cambio said.

Exactly what the rest is depends on the OCR you choose. Generally speaking, OCRs stitch together a series of obstacles with running segments between each new challenge. The obstacles can range from diving through mud pits to belly crawling under barbed wire to climbing over walls. And the distances vary greatly, too. OCRs for beginners start in the 5K range, or about 3 miles of total running between the various obstacles. More grueling challenges exist in OCRs that cover half or even full marathon distances (that means the latter of the two covers 26.2 miles, plus all the obstacles). These down and dirty races continue to be a popular draw. The United States Obstacle Course Racing (USOCR) association estimates that 3 million people worldwide participated in an OCR in 2016.

Cambio, a former college athlete, got his start in OCRs after a stint as a downhill mountain bike racer. He liked the obstacle elements of those races, which drew him to obstacle course racing. He signed up for the OCR nearest to his home in New Hampshire and was quickly hooked. Such races are now available nationwide, and he has traveled to many.

Some take place in stunning nature areas. Others are contained inside of professional sports stadiums, with the challenges including stair climbing and sprints through the corridors. There’s an OCR race for everyone, Cambio said.

Cambio enjoys OCRs for many reasons, including how they challenge the whole body — pulling up, squatting down, etc. He lists three essential elements an OCR novice should focus on before an event. First, a good sense of general athleticism goes a long way toward completing an OCR.

He also encourages novices to work on two other skills: time on their feet and grip strength. Time on your feet includes staying mobile for the time you plan to spend on the course.

“If you’re doing a 5K version, be sure you can walk around for 45 minutes,” he said.

The third element, grip strength, helps you grab onto ropes or the edges of obstacles slickened by rolling through muddy water. Fortunately, Cambio said, whole-body exercises such as pull ups, deadlifts and kettlebell routines improve general athleticism and grip strength at the same time.

A fourth unnamed element might be a little bit of grit. Cambio encourages any novice to give OCRs a try. After the finish line, a first-timer can assess what happened and work on a faster time or find more efficient ways through the obstacles. If anything is too tough the first time around, Cambio added OCR challengers can find assistance along the way.

“Someone is willing to help. If you’re struggling on a rope, they’ll help. There are always people who are willing to help. It’s such a community,” he said.

It can be a challenge. It is called an obstacle race, after all. But that’s part of the fun.

“Some things may be hard. But get out there and experience it,” Cambio said.