Brakken Kraker had just finished college in 2011 when he decided to take on his first Spartan Race. Though he’d been casual about his training since graduation, the former Division III runner believed he was by far the favorite to win.

“I had that really bad elitist mentality that most runners have,” Kraker, now a Spartan Pro Team member, says with a laugh. “Then I did my first barbed-wire crawl and I couldn’t lift my arms up.”

Many runners come into obstacle course racing (OCR) confident in their aerobic ability. But take it firsthand from some of the best in the world: Just because you’re crushing local 5Ks doesn’t mean you’re guaranteed a spot on the Spartan podium.

But you can get there—it’ll just take some adaptive training. We culled the best tips from runners-turned-OCR-pros to figure out how to best transition from the predictability of the road to the ever-changing demands of Spartan’s mud, fire, and ropes.

GET SPARTAN FIT! SIGN UP FOR OUR WORKOUT OF THE DAY NEWSLETTER AND HAVE OUR BEST TRAINING PLANS DELIVERED TO YOUR INBOX DAILY.

1. Lift and pull

Max King was a standout track athlete and marathoner before he moved to obstacle racing, so it was the upper body strength that concerned him most. After examining the obstacles, King discovered they could be distilled into two major movements: pulling and carrying. “I needed to focus on some specific movements rather than trying to add it all together,” he says. By throwing in kettlebell carries and pull-ups two or three times a week, he prepped himself for sandbags and rope climbs.

2. Embrace your weaknesses

While upper-body training is critical, you don't want to throw yourself in too fast. Rose Wetzel, a former Georgetown University scholarship half-miler who finished fifth at last year’s Spartan World Championship, had suffered a stress reaction in school. So in preparing for obstacles, she knew that sandbags and bucket-carries posed an injury risk. "I have to be mindful of putting a lot of load on my frame,” she says. So she eased her way into training, carrying just 20 pounds once a week for five minutes. After five months, she began to upshift. “After that, my body started to adapt, and then I worked my way up,” she says. The point: Be honest about your limitations, and then practice dedicated patience to overcome them.

3. Buy a ladder

Faye Stenning is a Canadian prep record-holder in the 3,000-meter (approximately two miles), so she spent most of her early life running in a straight line or around the track. “I did very little side-to-side work,” she says. Her solution—and one that helped her become the 2016 Spartan Championship Series runner-up—was to add lateral-mobility work to her routine. She now works out with an agility ladder—the same type that football players use.

4. Keep on running

After Kraker’s first humbling experience in a Spartan Race, he threw himself into strength training, hammering intervals on the track with pushups and squat jumps in between. He’d do it as often as four times a week, ignoring his regular running routine. Two months later, at the World Championships? “I could do obstacles now, but I sucked at running distance,” he says. His advice: If you’re serious about your race time, then don't let new workouts completely displace the running routine that got you where you are. “A new obstacle hits, and then athletes all put a ton of emphasis on that,” he says. “Eventually, everyone’s good at it, and it comes down to a footrace again.”

5. Change up the scenery

Of course, the terrain at a Spartan race is nothing like that of a track. Road runners are used to the predictability of asphalt, but OCR has anything but. “I realized that my beautifully groomed trails weren’t cutting it for me,” says Wetzel. So she moved to Colorado for six months to gain access to gnarlier terrain. You don't necessarily have to move to Colorado, but you should move at least some of your runs to hiking trails—the rougher the better. Hills, mud, and rocky terrain are all critical training tools.

6. Time your strength work

Stenning discovered something about resistance training: It can throw off your long-run days. “It definitely affects your training quality,” she says. “You’re not going to be able to run quite as fast the days after.” So the best time to do strength work, she says, is the same day of your harder runs, ideally immediately following your last stride. Sound hard? It is. And that's the point.