Stu McGill could see my problem the moment I sat down on his couch. I was there to interview him for a magazine story, but what I really wanted to know is why, after decades of lifting, my back had suddenly started to hurt during basic exercises like squats and deadlifts.
So he watched how I positioned myself in a classic manspread, with my torso leaning forward and my feet angled out—a position, I would soon learn, that's determined by the shape and configuration of my hip joints.
McGill, a professor emeritus of spine biomechanics at the University of Waterloo in Canada, is among the world's most sought-after specialists in back pain. He's used to solving the toughest cases, with a client list that includes MMA champions, record-setting powerlifters, and even some doctors who specialize in back problems but can't resolve their own.
My case wasn't tough at all. Unless my form on the squat matched the unique structure of my hips (it didn't), it was only a matter of time before I hurt myself.
Since then I've noticed subtle differences in the ways guys sit—the breadth of their spread, how much they lean forward or back, and whether their feet angle out evenly or asymmetrically. (My left foot goes out farther than my right, another reason conventional exercise form would cause a problem sooner or later.) All reflect the nearly infinite variations in pelvic structure, along with the manspreader's ancestral origins.
But if you see the word "manspread" in an article or opinion piece, you can bet it's not going to be about how it's natural for women to sit with their knees close together and ankles crossed, but the same position can be painful for a guy like me.
You're more likely to read stories like this one from Mic, which accurately notes that any space men and women occupy is "inherently gendered." But it attributes these gender differences not to anatomy, or even to obliviousness on the part of men who don't seem to notice they've expanded beyond any reasonable definition of personal space. Instead, it links manspreading to power dynamics, saying it "doesn't just make people feel more entitled, it also makes them more likely to steal, cheat, and fail to respect traffic laws." That's right: If you manspread, you're basically Trump without the golf courses.
McGill had never heard the term "manspreading" before we spoke, but he immediately thought of a context that explains how it relates to his work with elite strength athletes. Here, for example, is a picture of the legendary Russian weightlifter Vasily Alekseyev sitting side by side with a photo of him lifting.
Pretty much the same angle, right? The same applies to me, even though I'm half the size of the 350-pound Alekseyev. I know that because McGill used the two tests shown in this video to determine my ideal squat form. (You can do the second test, the hip rock-back, on your own.) "Most men will find the least-stressed sitting position is with their knees apart," he says.
Here's what happens when someone like me sits with my knees close together: The round ball at the top of the femur will pinch against the outside edge of the acetabulum (the hip socket), straining the labrum that lines the socket. To get into that position, I have to activate the adductor muscles on my inner thighs. That automatically triggers resistance from the abductor muscles on my outer thighs, creating tension that can reach all the way up into the lower back. The second I release the contraction, my thighs spring apart, leaving a gap of about 15 inches from the center of each kneecap, more than three-quarters of the distance to a proper manspread.
Women, on the other hand, have a wider pelvis and thighbones that more naturally angle in toward the body's midline, rather than away from it. Sitting with the knees close together is a stress-free position most of the time, although that changes during pregnancy, when the weight of the belly pushes the knees out.
Differences in hip anatomy aren't just gender-specific. They differ by your regional ancestry as well. One fascinating consequence of these differences, McGill says, is the close relationship between orthopedic disease rates and athletic ability. Poland, for example, is the epicenter of hip dysplasia—hips coming out of the socket. But because shallow hip sockets allow deep, ass-to-calves squats, Poland also produces a lot of great Olympic weightlifters.
By contrast, those with Celtic hips are far more likely to suffer from hip impingement, a consequence of the limited range of motion caused by their deep hip sockets. Those deep sockets put them at a disadvantage at the bottom of a squat, but allow them to generate tremendous power from a more upright stance. That helps explain why Scots invented golf and caber tossing and Brits popularized upright, bare-knuckle boxing.
Meanwhile, on the other side of the globe, Asian martial arts use a lower center of gravity and extreme hip mobility to turn a potential opponent's size and strength into a disadvantage.
You can even see it in folk traditions. The Ukrainian Cossack dance is made possible by relatively short femurs, while Irish step dancing wouldn't have taken hold in a population where people could easily do a split.
None of this, to be clear, justifies guys being assholes on public transportation, where we all have to put up with a little discomfort to coexist. Nor is it another take on the dick-and-balls defense, which argues that without manspreading we'll crush our testicles between our awesomely powerful adductor muscles. I'm a proud member of the penile-American community, but I guarantee it doesn't take much of a spread to avoid squeezing Frank and his two nutty friends.
But it's not like the anti-manspreading arguments have risen above specious reasoning. Take that study mentioned in the Mic article. Titled "The Ergonomics of Dishonesty," it doesn't actually address gender. Moreover, if you read to the end, you'll see its conclusions aren't entirely negative. It notes that "incidentally expansive postures" can have positive effects, including "resilience from pain and stress" and "prosocial and socially responsible outcomes if the situational cues for such goals are salient."
So I'll put this out there for my fellow bearers of the Y chromosome: With great manspreads come great responsibility. We don't need to apologize for expanding to fill the available space. But when that space isn't available, it's on us to take one for the team and reel that shit in.