People are obsessed with mastering the obstacles in a Spartan race, and who can blame them? Conquering the Herc Hoist delivers that oh-so-sweet rush of adrenaline and fuzzy feelings of personal accomplishment. But once you scale that wall, climb that rope, or throw that spear, that high quickly fades as you run and run and run—through miles of woods, fields, or straight-up mountain goat trails before hitting another obstacle. If your running endurance is not on point? You. Will. Suffer. This one-month Spartan workout plan is here to help.

“People spend more time running in a race than they will on all of the obstacles combined, and all of our best athletes are great runners,” says Jeff Godin, Ph.D., CSCS. He also points out that being a proficient runner can improve your obstacle performance. “You won’t arrive at the rope climb completely gassed and have to stand around and rest before you attempt it, or miss the obstacle because you are too tired—then have to do burpees,” says Godin.

If you truly want to improve your time, you need to build on your stamina. Godin did the math: “If someone walks, they may average a 20-minute mile. If they jog it drops to a 12-minute mile. And if they’re fast they may average a 10-minute mile. Over an eight-mile course, you could save 60 to 90 minutes.”

Your One-Month Spartan Workout Plan

As written, this one-month Spartan workout plan/program is perfect for the novice or intermediate athlete wanting to run a Spartan Sprint. For a Super, follow this one-month workout plan for two months, and for a Beast three months or more. “To do a Sprint, you have to be able to comfortably run five miles, a Super 10 miles, and a Beast 16 miles,” says Godin. “The actual race distances are shorter, but over-running ensures you have some endurance in the bank when things get tough.”

Related: Hill and Mountain Racing 101

Each week you’ll do five kinds of workouts within the one-month workout plan: lactate threshold (LT) runs, strength + HIIT, hill repeats, long runs, and yoga or recovery. You build both intensity and duration the first three weeks; the fourth week is recovery. “Recovery week should be a 50 to 75 percent reduction in volume,” says Godin. “But the intensity remains the same.”

Lactate Threshold Runs

“The technical definition of lactate threshold is when lactate begins to accumulate in the blood above baseline values,” says Godin. “This accumulation represents a transition from moderate to hard exercise intensity.” LT runs should be done at a comfortably hard pace—you should be breathing heavy and can’t really engage in conversation, you but could put a sentence together if you were crying for help, according to Godin.

For longer races, there’s no progression here—your LT runs should stay the same. “Presumably as fitness improves you will be running faster and cover more distance, thus overloading,” Godin says.

Strength + HIIT Circuit

Do total-body workouts that focus on compound movements using heavier resistance with longer recovery time in between for your strength work. And for HIIT anything is fair game from plyometrics to bodyweight moves to tabatas. For example, if you never hit your spear throw, a good HIIT to practice would be 30 seconds of burpees followed by 10 seconds rest. Repeat ad nasueum to maximize this Spartan workout plan.

Long Runs

Start with a four-mile run in week one and increase that distance by 10 to 15 percent each week. By race day you should be able to cover 5-1/2 miles, no problem. For longer races, Godin recommends continuing the same building pattern until you reach your recommended distance.

And if possible, nix the treadmill. “Running on treadmill engages the muscles differently as compared to running the road or trails,” says Godin. “Trails are very unpredictable. There are constant ups and down and the changes are rapid. The body needs to be ready for these changes.”

Related: Why You Should Be Running Stairs to Get Stronger and Faster

Whether it’s snowing, raining, or beautiful and sunny, do your runs outside on a natural surface. You’ll engage more foot, lower leg, and core muscles as you manage the terrain and will be more prepared to face the elements when they arise—and they will arise. 

Important note: Absolute beginners should log some distance and build an aerobic base before starting this 4-week program. Godin recommends two days a week running two miles at an easy pace. Each week, add a half-mile to those runs. For the third workout, he recommends a 4-mile walk-run at a 1:4 ratio. As you improve, “Progress the distance while keeping the ratio the same,” says Godin. “Once you reach maximal distance for the race you want to do, then work toward more running and less walking.”

Hill Repeats

Find a long hill that takes about 4 minutes to run up. Warm up thoroughly, then sprint up the hill and walk down for recovery. As soon as you hit the bottom sprint up again. Begin with four reps and add a rep every week for two weeks. When training for a longer race, “Hill Repeats can build to 8 reps but any more than that is overkill,” says Godin. “Again, the overload is that you should be doing them faster and harder.”

This is the only workout in this Spartan workout plan where there’s a pass for using cardio machinery. “If you don’t have a hill, you can use a treadmill, or even a parking garage,” suggests Godin.

Yoga or Recovery

Recovery days are important for all athletes, and Godin has included two per week in this Spartan workout plan. Do something that mobilizes your muscles and joints without causing you to sweat profusely, such as gentle yoga, recreational walking, or hiking, or easy biking. This will get your blood moving, shuttle wastes from your cells and gently stretch your muscles.