Heads and shoulders essential to running
Study finds upper body coordination keeps us upright
We can thank early human evolution that many of us can enjoy running as much as we do.
Watch anyone with a ponytail run, and you can see their hair repeatedly describe a figure-eight in the air, responding to the forces generated by the running. But their heads stay still, their eyes and gaze level.
If it weren’t for some unique evolutionary advances, our heads would do the same as that ponytail, flopping like a swim noodle when we run, according to a clever new study of how — and why — our upper bodies seem to work the way they do when we run, but not when we walk. The study, which involved treadmills, motion capture, hand weights and an eon’s worth of back story, finds that an unusual coordination between certain muscles in runners’ shoulders and arms helps to keep heads stable and runners upright.
The new findings may answer lingering questions about the role of our upper bodies in running and why we, unthinkingly, bend and swing our arms with each stride. They also add to the mounting evidence that, long ago, distance running began shaping human bodies and lives in ways that still reverberate today.
The possibility that we humans are born to run has inspired many studies, books, lectures and debates in recent years, including journalist Christopher McDougall’s 2009 bestseller, “Born to Run.” The idea is based on fossil research indicating that early humans evolved to have distinctive leg bones and other characteristics that would have aided distance running. The findings suggest that those of our ancestors who could run well dominated in the procuring-food and procreating sweepstakes, so that natural selection started favoring physical characteristics associated with running.
Much of this research came from the mind and laboratory of Daniel Lieberman, a professor of human evolutionary anatomy at Harvard University and author of the new book “Exercised,” which delves into exercise and evolution. At first, most of his and other scientists’ work related to evolution and running centered on lower bodies, since legs play such an obvious part in how we get from one place to another.
But Lieberman also was interested in runners’ upper bodies and, especially, their heads. As a longtime marathon runner himself, he knew that a stable head is critical for successful running, but not necessarily a simple thing to achieve. Running is propulsive. You push off, rise and then brake forcefully against the ground with every stride, placing forces on your head that could make it flop uncontrollably, like that bobbing ponytail.
How we manage to keep our heads stable, however, has not been altogether clear. Like most cursorial species, or animals that run, including dogs and horses, we have a well-developed nuchal ligament, a tissue that connects the skull and neck. That is not the case in species that aren’t natural runners, like apes or swine.
When he was a young scientist, Lieberman recalled, he enticed pigs — who are inelegant runners — onto treadmills to study their biomechanics. Their heads jiggled like bobbleheads when they were forced to run, prompting Lieberman and his colleagues to conclude they lacked a nuchal ligament, a finding borne out by anatomical studies.
But we humans also have the challenge of being upright, on two legs. Presumably to balance ourselves while running, we began, at some point, to swing our arms. Lieberman guessed that the arm swing helped to stabilize our heads. But, if so, there would have to be coordination between the muscles in our forearms and shoulders, he thought, even though these muscles do not physically connect. They would need to fire together and with comparable force during running, if they were to be successful in stabilizing our heads.
He was uncertain about how to test that theory, though, until his colleague Andrew Yegian, a college fellow in the Department of Human Evolutionary Biology at Harvard, suggested weighting runners’ arms and heads. Add mass there, he said, watch how the muscles respond, and you would be able to tell if the arms and shoulders were working together to steady the head or not.
So, for the new study, which was recently published in the American Journal of Physical Anthropology, Lieberman, Yegian and their colleagues fitted 13 men and women with sensors on their upper bodies that track muscle activity and asked them to first walk and then run on a treadmill while the researchers filmed them with motion-capture technology. Then the scientists handed the volunteers light hand weights and asked them to run again. Finally, they strapped weighted masks to the volunteers’ faces and had them run once more, before comparing how everyone’s muscles had responded to each of these interventions.
It turned out that not much of interest happened while the study volunteers walked; the muscles in their forearms and shoulders showed no evidence of coordinated activity.
But those same muscles snapped into synchronized action when the volunteers started to run; the muscles began firing at the same time and with about the same amount of force.
That synchrony grew during the weighted runs. When the volunteers carried weights and their forearm muscles fired with extra force to compensate, the muscles in their shoulders did the same. Similarly, when their weighted faces prompted the runners’ shoulder muscles to fire more forcefully, their arm muscles did likewise.
The study does not explain how these widely separate muscles communicate with one another, though. Nor can the findings pinpoint when, in our existence as a species, they may have started to work together in this way. It also does not prove that all of us are natural born runners; plenty of people do not enjoy the sport.
Still, the results do tell us more than we knew before about our bodies, Lieberman says, and underscore that running molded us as a species.
“If we didn’t have to run” in our early days as humans, he says, “we wouldn’t have this system” of muscular interplay today.
A FedEx driver handcrafting soaps. A hairstylist hawking porkless bao buns. A restaurant manager repurposing denim jackets.
The dream of turning a hobby into a Plan B career is almost a cliche of the gig economy, with countless tips published on selling vintage comic books, brewing beer, playing video games and even telling jokes.
After a year scarred by the coronavirus pandemic, however, in which millions of Americans lost their jobs according to the Bureau of Labor Statistics, it’s starting to look more like a necessity than a fantasy, particularly for people who have been laid off or forced to step away from jobs to tend remote-schooled children.
Yelp recorded nearly 100,000 business closures during the first eight months of 2020, but also a 10% rise in new businesses selling cupcakes, doughnuts, cakes, macarons and other desserts. Etsy saw a 42% spike in new sellers in the third quarter of 2020, compared with the year before.
“It could be that some just wanted to answer their creative calling,” said Dayna Isom Johnson, Etsy’s trend expert. “But for many during this unprecedented time, it’s about people who have faced unexpected financial challenges, whether they are unemployed or furloughed by their jobs.”
Here are three who made the leap during the pandemic:
Pressing vinyl in the basement
“A lot of people are looking to get into IT work,”
said Eric Warner, a web programmer in Chippewa Falls, Wisconsin. “I am looking to get out.”
Quarantine may have given him just the nudge he needed.
While isolated at home with his wife and two children, Warner, 46, started a second career he hopes to make his primary source of income: cutting custom vinyl records in his basement, often as gifts for anniversaries and birthdays.
Two years ago, he bought a $10,000 record lathe.
It is a highly specialized machine that feeds an analog signal to a diamond stylus that carves grooves into a blank disk.
As a former rave producer, Warner dreamed of starting an ambient-music indie label, Abstrakt Xpressions, but
the machine mostly sat in the basement. Until the pandemic.
His wife, Izabella, 43, who designs online courses for universities, was unable to look for work, and he had to cut back on web-design clients to help raise their children, aged 5 and 11. Days were hard and long.
Seeking a more commercial application for his lathe, the couple opened an Etsy shop called Vinylus, selling bespoke albums — basically, vinyl mix tapes — with custom artwork for $95 to $110.
Fancy haircuts to bao buns
As a private hairstylist to Nike designers, Amazon executives and other welloff clients, Thuy Pham was living the life.
“I was able to make good money working only three
to four days a week, which was a great schedule for a single mom,” said Pham,
40, who lives in Portland, Oregon, with her 7-year-old daughter, Kinsley. “I was traveling, going to music festivals. When you have a career like that, why would you consider leaving?”
Then Portland went into lockdown in March, shuttering her business. To pass the time, she began scouring YouTube for Vietnamese meat-free recipes (Pham is vegan), including mock-pork belly made with coconut milk, tapioca and rice starches, in the traditional style of Vietnamese Buddhist monks.
“Cooking for me was always a way to share love and affection with my family,” said Pham, who came from Vietnam to the United States as a refugee in the 1980s.
She was pretty happy with her results, so in April she livestreamed the recipe on Instagram as a way of keeping in touch with her hair clients. “Within minutes of going live, I had customers asking to buy my pork belly slabs,” she said. “I immediately thought that this could be a way for me to make ends meet until I could go back to work as a hairstylist.”
By week’s end, Pham had filled 100 orders. Within two weeks, she was shipping nationwide.
In November, she opened a Vietnamese delicatessen called Mama Dut (which means “mama, feed”) in the city’s Buckman neighborhood, selling porkless bao buns, mushroom banh mi and other signature creations for takeout and bicycle delivery.
Business has been brisk.
Pham hopes to make $350,000 in revenue this year and wants to expand Mama Dut to Los Angeles.
Sudsy side hustle
When schools closed in March because of the pandemic, Tiffany Dangerfield, 31, of Huntsville, Alabama, had a difficult choice: continue working long days as a delivery driver for FedEx or stay at home with her three children.
“There was no way my 4-year old was going to put himself on the live class meeting every morning,” Dangerfield said.
She took over teacher duties at home, while her husband, James Dangerfield, 31, worked as an assembly operator for a local defense contractor. Money was tight, but she soon found another income stream.
About a decade ago, her husband was a corporal in the Army stationed in Vicenza, Italy, and her young son and daughter were suffering from eczema and chronic dry skin. Nothing that doctors on the base prescribed proved helpful, so she started making chemical-free soaps.
She made soaps for family and friends, and when the pandemic hit, they persuaded her to sell them online. Before long, Dangerfield had converted her dining room into a studio cluttered with jugs of oils, mixing bowls and packing materials. And she began selling confectionlike blackberry and vanilla soap, cedar-scented body butter and coconut oil sugar scrubs on her Etsy shop, We Made It Soap Co.
It took months to gain traction. She now fills more than 30 orders a month for whimsical products such as pheromones-activated charcoal soap ($7), coffeewhipped sugar scrub ($8) and black-raspberry-vanilla whipped body butter ($9).