What’s the difference between hiking 2 mph and 3 mph? About 5 miles of bonus wilderness a day. When it comes to a picking up the pace, lightweight gear can only do so much; improved fitness will do the rest. To get there, we recommend interval training-a method that alternates brief, intense exercise with recovery periods.

Intervals will help you go farther, says Jenny Hadfield, veteran adventure racer and co-owner of Chicago Endurance Sports, but they’ll also condition you to trek through the toughest terrain with less fatigue. She shares her three favorites at right. Do two workouts a week, with at least one day of recovery between. Warm up and cool down with 10 minutes of jogging and stretching.

3 On, 3 Off

Powerful lungs mean powerful climbs. To increase your body’s ability to utilize energy, run hard for 3 minutes (an 8 on a 1 to 10 intensity scale), then recover by walking or jogging for 3 minutes (intensity level 3). Start with four reps, build to eight.

Calisthenics

Alternating strengthening exercises and running conditions the body to keep moving even when it’s tired. Alternate 3 minutes of calisthenics (intensity level 8) with 3 minutes of moderate jogging. Do one set each: Push-ups, walking lunges, jumping jacks, ab crunches, and jump squats (jumps from a squat position) for a 30-minute workout.

Stair Repeats

Running up and down the relentless pitch of stairs builds both lung and leg power and mimics the terrain of a tough trail. Find a long flight of stairs (office building, stadium). Strap on a weighted pack (start with 10 pounds, progress to actual pack weight). Ascend hard by stepping fast or taking two steps at a time (intensity level 8). Descend in a slow, controlled manner. Start with 20 minutes; build to 50.

First-aid Ready: Restock your kit after every trip. Replace bandages, painkillers, and moleskin.