To see if you're bending correctly, try a simple experiment.
"Stand up and put your hands on your waist," says Jean Couch, who has been helping people get out of back pain for 25 years at her studio in Palo Alto, Calif.
"Now imagine I've dropped a feather in front of your feet and asked to pick it up," Couch says. "Usually everybody immediately moves their heads and looks down."
That little look down bends your spine and triggers your stomach to do a little crunch. "You've already started to bend incorrectly — at your waist," Couch says. "Almost everyone in the U.S. bends at the stomach."
In the process, our backs curve into the letter "C" — or, as Couch says, "We all look like really folded cashews."
In other words, when we bend over in the U.S., most of us look like nuts!
But in many parts of the world, people don't look like cashews when they bend over. Instead, you see something very different.
I first noticed this mysterious bending style in 2014 while covering the Ebola outbreak. We were driving on a back road in the rain forest of Liberia and every now and then, we would pass women working in their gardens. The women had striking silhouettes: They were bent over with their backs nearly straight. But they weren't squatting with a vertical back. Instead, their backs were parallel to the ground. They looked like tables.
After returning home, I started seeing this "table" bending in photos all around the world — an older woman planting rice in Madagascar, a Mayan woman bending over at a market in Guatemala and women farming grass in northern India. This bending seemed to be common in many places, except in Western societies.
"The anthropologists have noted exactly what you're saying for years," says Stuart McGill, at the University of Waterloo in Ontario, Canada, who has been studying the biomechanics of the spine for more than three decades.
"It's called hip hinging," McGill says. "And I've spent my career trying to prove it's a better way of bending than what we do."
For starters, McGill says, it's "spine-sparing."
When people bend with the cashew shape in their back — like we often do — they're bending their spine. "That puts more stress on the spinal disks," McGill says.
Disks are little rings of collagen found between each vertebra, which form a joint. But they aren't made for tons of motion. "They have the mechanical characteristics of more like a fabric," McGill says.
"If you took a cloth, and you kept bending and stressing it, over and over again, the fibers of the weave of the cloth start to loosen up and delaminate," he says.
Eventually, over time, this fabric can fray, which puts you at risk of slipping a disk or having back pain.
On the other hand, when you hip hinge, your spine stays in a neutral position. The bending occurs at the hip joint — which is the king of motion.
"Hips are a ball and socket joints," McGill says. "They are designed to have maximum movement lots of muscle force."
In other words, your boots may be made for walking, but your hips are made for bending.
"Bending at the hip takes the pressure off the back muscles," says Liza Shapiro, who studies primate locomotion at the University of Texas, Austin. "Instead, you engage your hamstring muscles."
And by "engage the hamstrings," she also means stretching them.
"Oh yes! In order to hip hinge properly, your hamstrings have to lengthen," Shapiro says. "If you have tight hamstrings, they prevent you from bending over easily in that way."
Tight hamstrings are extremely common in the U.S., Kennedy says. They may be one reason why hip hinging has faded from our culture: Stiff hamstrings are literally hamstringing our ability to bend properly.
But hip hinging isn't totally lost from our culture, Shapiro says. "I just saw a website on gardening that recommended it, and many yoga websites recommend bending at the hips, too."
And the hip hinging is sprinkled throughout sports. Weightlifters use it when they do what's called a deadlift. Baseball players use it when they bat. Tennis star Rafael Nadal does it when he sets up a forehand. And in football, players kneel at the line of scrimmage with beautiful hip hinging.
Toddlers younger than 3 years old are great hip hingers. They haven't learned yet from their parents to bend like a cashew.
Whether or not hip hinging will prevent back pain or injuries, doctors don't know yet, says Dr. D.J. Kennedy, a spine specialist at Stanford University and a former weightlifter.
"We don't have these randomized trials, where we have people lifting things hundreds of times and see how their body responds to hip hinging," Kennedy says.
Still, though, Kennedy says he tries to hip hinge as much as possible.
"I think hip hinging intuitively makes sense, just given how the spine functions," he says. "So I try very hard to do it."
So how in the world do you do this mysterious bending? Back in Palo Alto at Jean Couch's Balance Center, she tells me the trick: Find your fig leaf.
"Stand up and spread your heels about 12 inches apart, with your toes 14 inches apart," she says. "Now, if you are Adam in the Bible, where would you put a fig leaf?"
"Uh, on my pubic bone?" I answer shyly.
"Exactly," Couch says. "Now put your hand right there, on your fig leaf. When you bend, you want to let this fig leaf — your pubic bone — move through your legs. It moves down and back."
So I try it. I put my hand on my pubic bone as a pretend fig leaf. Then as I bend my knees a bit, I allow my fig leaf to move through my legs. A little crevice forms right at the top of my legs and my back starts to fold over, like a flat table.
"Now you're using the large muscles of your hips, such as the glutes, to support the whole weight of your body, instead of the tiny muscles of your back," says Jenn Sherer, who co-owns the Balance Center with Couch.
And she's right. My back relaxes, while my hamstrings start to stretch. And boy are they tight!
"Wow! My hamstrings are stretching like crazy," I yell out, while I'm bent over like a table.
"Yes," Couch says, chuckling. "That's why we call it the world's best hamstring stretch. We find that the bend feels so good for some people, they never want to get back up."
STEVE INSKEEP, HOST:
Here's something people do every day that many of us apparently do wrong - bending over, you know, to pick things up or put things down or even just to sit down. Now, a group of scientists who study bending say Americans are doing it in a way that may make back pain more common. NPR's Michaeleen Doucleff reports.
MICHAELEEN DOUCLEFF, BYLINE: We're going to start off with an experiment. Our guide is Jean Couch who's been helping people in Palo Alto, Calif., get out of back pain for 25 years. She says stand up.
JEAN COUCH: Put your hands on your waist.
DOUCLEFF: Now imagine something on the ground in front of you, like a feather.
COUCH: If I said pick up a feather, usually everybody the first thing they move is their head.
DOUCLEFF: And you look down.
DOUCLEFF: That little look down is already making you bend in the wrong way - at the waist.
COUCH: And right away, they've begun to bend the spine.
DOUCLEFF: Oh, yeah, my stomach crunched.
DOUCLEFF: Which makes our backs curve into a C shape. Like...
COUCH: Really folded cashews.
DOUCLEFF: Cashews. In other words, when we bend, we kind of look like nuts - cashew nuts. Seriously, though, in many parts of the world, people don't look this way when they bend. Instead, you see something very different. I first noticed it back in 2014 while covering the Ebola outbreak. I was in eastern Liberia, and women working in their gardens were bending over in a way I had never seen before. Their backs were perfectly flat, and they weren't squatting with a vertical back. No, their backs were horizontal, parallel to the ground. Their backs looked like tables. I started noticing this type of bending in many rural places - women planting rice in Madagascar, men picking up mangoes in Nepal. The bending seemed to be everywhere except here.
STUART MCGILL: The anthropologists have noted exactly what you're saying for years.
DOUCLEFF: That's Stuart McGill at the University of Waterloo in Ontario. He studies the biomechanics of the spine and says people make this table with their back because they're doing a special type of bending called...
MCGILL: Hip hinge.
DOUCLEFF: Hip hinge.
MCGILL: Focusing more of the motion around the hip joint.
DOUCLEFF: Do you think that this is more optimal than the way we bend over?
MCGILL: Oh, absolutely.
DOUCLEFF: McGill says when people been with the C shape in their back like we do, they're bending their spine.
MCGILL: That puts more stress on the spinal discs.
DOUCLEFF: Those little rings of collagen between the vertebrae. McGill says discs aren't the strongest part of our body. They're kind of like a delicately woven fabric.
MCGILL: If you took a cloth and you kept bending it and stressing it over and over again, the fibers of the weave of the cloth start to loosen up and delaminate.
DOUCLEFF: And eventually over time, this fabric can fray. That puts you at risk of slipping a disc. But when you hip hinge, or make the table with your back, your spine stays straight, and the bending occurs at your hip joint, which is the king of motion.
MCGILL: The hips are ball-and-socket joints. They are designed to have maximum movement, lots of muscle force, et cetera.
DOUCLEFF: In other words, your boots may be made for walking, but your hips are made for bending. But most of us aren't using them that way.
MCGILL: So this wisdom of movement really has been lost in our society.
DOUCLEFF: Lost but not totally forgotten. There are a few places where you still see a lot of hip hinging today. Weightlifters use it when they do what's called a deadlift. And...
(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED ANNOUNCER: Evans powering his way forward.
DOUCLEFF: Yep, football.
(SOUNDBITE OF ARCHIVED RECORDING)
UNIDENTIFIED ANNOUNCER: Touchdown.
DOUCLEFF: Players kneel at the line of scrimmage with beautiful hip hinging. D.J. Kennedy is a spine specialist at Stanford University and a former weightlifter. He says doctors don't know enough about hip hinging to say whether or not it will prevent back pain or injuries.
D J KENNEDY: We don't have these randomized trials where we put people lifting things hundreds of times and see how their body responds to it. But I think it intuitively makes sense from how the spine functions.
DOUCLEFF: And so do you hip hinge?
KENNEDY: I try. When I lift weights, I'm very mindful of my form. So I try very hard to do it.
DOUCLEFF: Personally, for me, it took a few months to learn how to hip hinge, but once I got the hang of it, I'm never going back to looking like a cashew. Michaeleen Doucleff, NPR News.
(SOUNDBITE OF SUN GLITTERS' "WHAT ARE WE WAITING FOR")
INSKEEP: To learn how to hip hinge, go online to NPR's health blog, Shots.
(SOUNDBITE OF SUN GLITTERS' "WHAT ARE WE WAITING FOR") Transcript provided by NPR, Copyright NPR.