Fitness crazes come and go, often involving special equipment and strange diets. But a new approach that’s gaining popularity is something anyone can relate to. It involves crawling. Yes, the kind of crawling on all fours you used to do as a child. 

Already popularized in physical therapy, crawling has been gaining traction to increase strength and fitness in the U.S. as well as in China.

Why does it work? 

"You can crawl in many ways. You can crawl on your hands and knees. You can also prop up on your toes and just hover, one or two inches above the ground, which is really going to pull in those core muscles and work those muscles effectively," said Danielle Johnson, a physical therapist at Minnesota’s Mayo Clinic Healthy Living Program. "Then, as you start to move, you're working on your shoulder girdle, you're working on your hips. If I could give one exercise to almost everybody, this would be it."

The popularization of such an unexpected exercise comes courtesy of the “Original Strength Training System,” whose expressed purpose is to make people “reset their operating system using a way they already know, one which we all used early in our lives”. 

How do people crawling in a hallway look like? Here’s an Instagram peek from the Original Strength folks:

The “reset” the system’s creators are championing is a way to reboot the central nervous system and re-learn a way to move like a child. 

This is what the creators of the approach aim for (as described on their site):

“We want to reintroduce you to your original self, the one who could squat down to pick things up, look up in the sky to watch birds or see shapes in clouds.  The one who used to walk from place to place or up and down stairs without worry of falling. More importantly, we want to reintroduce you to fun and feeling better with improved energy, memory and the joy of hope and movement.”

The scientific verdict on such a “reset” is still out, with some cautioning that it might not be appropriate for people suffering from knee pain. Still crawling has been making inroads with many professionals, like the chiropractor Justin Klein, whose clients include pro athletes like Denard Span, a San Francisco Giants center fielder.

"It's like resetting the central loop in the nervous system to bring all of the parts involved in coordination, movement and reflexive stability into synchronization," he said to CNN. "You have to really work to be able to breathe, keep your head up and crawl at the same time, all while keeping your pattern," he said. "That's the kind of thing where, if you are being really mindful within your crawl, it is harder than it looks."

Here's how Justin Klein’s “Crawl on the Mall” event in Washington, DC looked like:

Will crawling will make its way over to Congress as a daily fitness (and humility) break?  Let’s hope it catches on. 

The ease of adding crawling to a fitness routine is what excites some people in the fitness industry like Jaclyn Emerick of Shape magazine.

"Crawling is super accessible; it's body weight. To a lot of people, it feels new, so anything that feels new is exciting, and they're more willing to try it, and it's not something that requires you to do for a very long amount of time. You can maybe do some intervals with it," said Emerick. "Crawling doesn't have to eliminate other good things that exist -- you're seeing people compare this, like 'it's the better plank' -- there's room for lots of good things. It's just another cool move, another cool exercise to add to your arsenal."

How do you actually use crawling as exercise? We won’t try to teach you to crawl here but do keep your back straight, when you do it. That’s key according to the experts.

Cover photo: Wombats players crawl up a grass hill during a Singapore Wombats Aussie Rules training session at Fort Canning Park on February 23, 2013 in Singapore. (Photo by Cameron Spencer/Getty Images)