National Geographic News
A comparison of two footprints.

A comparison of two human footprints.

Image courtesy Jeremy Michael De Silva

Harmony Huskinson

National Geographic

Published June 6, 2013

Jeremy DeSilva could see something was afoot. He just couldn't believe it.

As shoeless visitors strolled along a mechanized gait carpet in the Boston Museum of Science's Living Laboratory, sensors detected pressure on the mid-outside portion of some pedestrians' feet. That suggested a midtarsal break—a type of footprint pressure DeSilva and other scientists associated only with gorillas and chimpanzees.

"It was shocking," said DeSilva, an assistant professor of anthropology at Boston University. "I mean, 80 years of research has argued that humans don't do this."

Or at least 80 years in DeSilva's field. Last month, when he published his study in the American Journal of Physical Anthropology, two podiatrists said they'd seen a similar variation in patients' feet. But they weren't familiar with the term "midtarsal break"—suggesting, DeSilva said, the need for "collaboration with as many different disciplines as possible."

Shared Ancestry

DeSilva connected his unexpected discovery—he was originally researching variations in the foot's arch—to a two-million-year-old fossil human called Australopithecus sediba. DeSilva's research suggests it moved like today's apes, which have bendy feet unbound by bones. Chimps, for instance, tumble through the tall trees of the jungle by molding both their hands and their feet around each branch.

In contrast, modern human feet tend to be rigid, with stiff ligaments that maintain bone position and facilitate our bipedal nature. (The same is true of most ancient feet as well; Australopithecus sediba is unique in the fossil record.) With high arches and stiff feet, we spring into our next step. DeSilva says wearing shoes may have played a role in reshaping our feet over the years.

But perhaps some people's feet can still manage ape-like feats. According to DeSilva's study, conducted over the past two summers, about 1 in 13 humans may have the midtarsal break in their feet.

Eyes on Feet

Using the gait carpet, a second footprint device, and a camera rig, DeSilva and his colleague Simone Gill, an occupational-therapy researcher, observed a midtarsal break—also known as  "floppy feet"—in 32 out of 398 adult participants.

"This [opens a] floodgate of questions," DeSilva said. "Who are these people? What is it about them that allows them to produce this motion?"

DeSilva noted that the floppy-footed folks he watched tended to have flatter feet and higher body mass indexes than the stiff-steppers. They also rolled their feet more: Employing a motion called hyperpronation, they landed on the outside of their feet and rolled dramatically inward. That, said DeSilva, allows the foot to relax its joints and ligaments and create a midtarsal break.

But it's all relative. Some subjects with floppier feet didn't technically have a midtarsal break, though their walking pattern came close.

The Walking Test

So how do you know if your feet might have a midtarsal break? Take a stroll on sand, DeSilva suggested. Here are a couple of tips:

  • Don't even bother to test your feet at the beach unless they're flat. If you have high arches, you probably have stiff muscles and ligaments—and decidedly unfloppy feet.
  • If you have a midtarsal break, the fold in your foot will pinch the sand upward. Look for a small ridge in the upper-mid portion of the footprint.

Taking the Next Step

This summer, DeSilva and Gill will take MRIs of many foot types and create models of them with 3-D printers. DeSilva will compare that data with the bones of Australopithecus sediba, while Gill will use the models to explore the relationship between foot anatomy and body types.

Of course, in a way we all have chimp feet. All primates possess—and have always possessed—26 bones in each foot. The structures of those bones all just look a bit different.

Meaning we all swing from the same tree—or once did.

Brian Rothbart
Brian Rothbart

'Floppy Feet' is one of the hallmark findings of the PreClinical Clubfoot Deformity (structure) present in a sizeable number of homo sapiens walking the earth today.  This is a very old foot structure found (I believe) in the foot fossils of Au.sebida.

Philip Tobias's concepts of bipedalism (The Tottering Biped 1982).  felt, as I  do, that modern homo sapien bipedalism is still imperfect.  He states: "After perhaps four million year or more, we have not yet evolved a fault-free mechanism.  Our bodies are still subject to what Sir Arthur Keith called the ills of uprightness. They include flat feet, slipped discs, hernias, prolapses and malposture."

Tobias belief's dovetail into what I have thought and written on the three embryological foot types (PreClinical Clubfoot Structure, Primus Metatarsus Supinatus foot structure and the plantargrade foot) all being present (I suggest) in the A.sebida foot, as they are today in the h. sapien foot (just in different proportions).
These three foot structures function very differently, which is seen in the foot prints they leave behind.  Without this understanding, erroneous conclusions can easily be made when examining the foot prints of our ancestors.
Professor Brian A Rothbart

John Melland
John Melland

As a Bigfoot person, this is great news. Bigfoot has that midtarsal break. Humans having that midtarsal break may show that Bigfoot is more closely related to humans than before. We can all draw some conclusions and theories about this new information. Its exciting news no matter how you walk on it. 

jimson james bringas
jimson james bringas

well i think this happens because of our genetic ape history.dolphins...  some found to have hind limbs reappeared.this is because they came from wolf like ancestor and definitely a land living mammals.therefore during the reproduction and development,the epigenome  changes due to environmental factors that leads to the formation of previous body plans.

Chandra Chauhan
Chandra Chauhan

I don't understand why this is a surprise since science already showed the evolutionary cycle between man and primates.

Sam Poore
Sam Poore

The problem is the test was conducted on "Bring Your Ape To Work Week."

Josh Bailey
Josh Bailey

Another nail in the coffin for creationism. I attempted walking with a midtarsal break. It required tensing of the foot muscles. I would say it would be over tight tendons pulling a bridge.

Lauren R
Lauren R

This is a discovery which is dramatically bigger than the press it's getting.

This is final proof not only of archaic interbreeding in human evolution -- but of it being so major (and likely so recent) as to leave a basic functional difference in some present-day humans.

This is everything that total-replacement Recent Out of Africa was invented by today's leftist-dominated human sciences establishment to cover up.

This is everything that the new revisionist Recent Out of Africa -- that allows only "tiny amounts" of mixing, and with no meaningful consequences -- is supposed to be heading off and damage-controlling, as full-genome DNA testing becomes commonplace.

This is present-day humanity not as a unified species, but as a fundamentally uneven mishmash, of not only different species, but different genuses going back millions of years. Having Australopithecine feet is nothing, compared to having a Homo erectus brain, with an IQ of 70, instead of the 140 of Cro-Magnon Homo sapiens sapiens.

The Denisova tooth is inarguably Australopithecine in morphology. Unless you simply silence the argument, with the current Orwellian total blackout on mentioning the tooth morphology in the science press.

The "Hobbit" from Flores Island shows this basic mechanism of human evolution at work: a local Australopithecine base, getting overlaid with Homo erectus interbreeding, and then Homo sapiens interbreeding.

And these Australopithecine mixes, in distinct regional variations, were present all around the Old World, into recent millennia -- in Ireland, where the ancestors of some of these Boston museum visitors likely came from, called leprechauns.


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