The #1 Fitness Trend Of 2015

American soldiers have been doing a simple fitness activity since the American Revolution, and it’s turned our military into the fittest, most feared fighting force in the history of the world.

That activity: rucking, or walking with a weighted pack on your back.

The activity gets its name from “ruck sacks,” which is military speak for “backpack.” “Rucking” is marching or walking while wearing your ruck sack (which is always loaded down with gear).

In training camps and in the field, soldiers may ruck up to 25 miles (or more) a day, grunting a pack that weighs upwards of 200 pounds.

But to build the body of a Navy SEAL, you don’t have to (nor should you) carry a pack weighing the equivalent of grown man. Just add a bit of weight to any old pack you have lying around the house, take a walk, and you’ll open up a whole new world of fitness.

“Rucking is great for the average person,” says Doug Kechijian, Doctor of Physical Therapy at Peak Performance, in New York City, and a former US Special Forces soldier. “It’s simple, and it delivers a lot of health and fitness benefits.”

It Crushes Calories
For the average guy, a 30-minute walk burns about 125 calories, according to the Compendium of Physical Activities. But throw a weighted backpack on and take that exact same walk, and you burn about 325 calories, also according to the Compendium of Physical Activities.

Just wearing a backpack with some weight in it makes walking incinerate nearly three times the calories!

Think about that. Let’s assume you take three, 30-minute walks each week. If you begin wearing a weighted pack, you’ll burn 31,200 more calories over the course of a year. That’s the amount of calories contained in nine pounds of fat.

“Rucking will make you look better, no doubt,” says Dan John, a famed strength coach located in Salt Lake City, Utah, and the author of Can You Go? “It’s especially great for fat loss.”

It Can Relieve and Prevent Back Pain
If you work out, you will probably experience back pain at some time. Why?

You probably spend a significant portion of your day sitting, with your back flexed forward. You get “used” to that position.

Then, when you hit the gym, if you lift with your back flexed it can cause a potentially-painful disc bulge, says Stu McGill, Ph.D. professor of spine biomechanics at the University of Waterloo in Ontario and the author of Ultimate Back Fitness and Performance.

People who have developed a disc bulge often lean forward when walking. This makes your situation worse, because your body has to fire your back muscles even harder to hold your torso up. “That puts more stress on the disc bulge,” says McGill.

Throwing a weighted backpack on and going for a walk actually helps hold your torso up, so your back muscles don’t have to work as hard.

“The net effect is that less compression is put on your spine, and the flexed forward posture that inflames the disc is reduced,” says McGill. “And it can also work disc gel (a disc bulge is caused by extruded disc gel) back into the middle of your disc, reducing the bulge.”

That, in turn, can help prevent and relieve your pain.