If you’re tired of sweating it out at the gym in hopes of losing weight, a classic military training exercise gets you outside and burning calories fast. But don’t worry — no obstacle course, pushups or sprints are involved. In fact, rucking is deceptively simple.

“Rucking is basically just walking with a weighted backpack or rucksack on,” says Jason McCarthy, founder of GORUCK and a veteran of the U.S. Army Special Forces. Carrying added weight increases the challenge of your walking workout and gets your heart rate up to burn more calories. Think of it as “cardio for people who hate cardio,” says McCarthy.

Here, everything you need to know about rucking for weight loss, according to military fitness pros.

“Rucking is the foundation of Special Forces training,” says McCarthy. “It’s known as a loaded march in the UK Military,” adds John Georgeson, a former Royal Marines Commando and certified personal trainer at Ultimate Performance in London. Out in the field, that means a mix of running and fast-paced walking loaded up with around 50 pounds (23kg) with a rucksack, rifle and gear. For those in the military, rucking is key for safely getting from point A to B, he explains. But for civilians, it’s as simple as strapping on a backpack, adding some weight and going for a walk.

Rucking is active resistance training or a mix of cardio and strength-training, says McCarthy, “which is the perfect combination for burning fat,” he says. “Cardio ups your heart rate and burns calories, while the strength gains from resistance training (carrying extra weight on your back) build lean muscle, which in turn boosts your metabolism.”

“Because you’re essentially doing a lot of repetition on the same muscle groups (your legs, core and back muscles), you’ll help build your endurance, too,” says Georgeson. That means more energy to put in quality sweat sessions and stay on track throughout your weight-loss journey.

What’s more, “by switching up your routine with rucking, you can beat exercise boredom and stay motivated,” says Georgeson. For days when the scale just isn’t moving, seeing how much weight you can carry and how far you can ruck serves as another great way to measure your progress. As you get stronger, adding more weight to your pack can serve as a confidence booster, too.

LACE UP SUPPORTIVE SNEAKERS

“Make sure to wear comfortable shoes with plenty of foot and ankle stability (hiking shoes are a good choice), since you’ll be carrying a heavier load and the ground may be uneven,” says Georgeson.

PICK THE RIGHT BACKPACK 

Choose a rucksack with well-padded shoulder straps and cinch them down. “You want your load to remain high and stable on your back,” says McCarthy.

LOAD IT UP

“Try your first ruck with 20 pounds (9kg),” suggests McCarthy. “If that’s too much, decrease the weight. If it’s not enough of a challenge, add more.” Scale up gradually in 10-pound (4.5kg) increments, keeping in mind the maximum amount of weight recommended on your back is 1/3 of your body weight.

FIND A FRIEND

Before you head out, recruit a workout buddy to join you or take your dog along. “We call it social fitness,” says McCarthy. “Being outside is a basic need we all have as human beings, as is being part of a community. The benefits of a walk outside with a friend, then maybe grabbing a healthy dinner together, are drastically underrated in our modern, busy lives.”

START SMALL

“If you’re just getting started, try rucking on even ground or pavement for 1 or 2 miles,” suggests McCarthy. Over time, you can up your walking routine by adding hills or uneven terrain, he says.

“In addition to a healthy, well-balanced diet, rucking is an ideal workout to do 1–3 times per week for weight loss,” says Georgeson. “Partner it with some full-body, military-style, boot camp workouts, and you’ll get in great shape in no time.”