Humans may have moved out of the trees, but some of us are still wandering around with vestiges of our arboreal ancestors: a flexible, chimp-like foot that bends in the middle.
After observing almost 400 adults walking barefoot around the Boston Museum of Science, researchers found that 8 percent of participants had a flexible midtarsal break in their foot, with a plantar pressure signature (where pressure is put on the foot) as had previously only been found in ape footprints.
People with a mid-foot break had flatter feet, and were likely to have a higher BMI than participants with rigid feet. Though the break was obvious to the researchers watching people walk, the subjects themselves were unaware of the difference, and it didn't affect their gait.
It's possible that the flexible joint is a vestige of our tree-climbing primate ancestors, but the study's lead author, Jeremy DeSilva, theorizes that the characteristic could have also popped up more recently due to the way shoes affect our feet. He told New Scientist he plans to test whether or not bendy feet make walking less efficient next.
...waits for the "WE AREN"T MONKEYS!" comments...
WE AREN'T MONKEYS! (We're Apes.)
Ah shucks, look at that boy; he is a chimp of the o'block!
Actually humans are product of development by an ancient interfering alien visitors (Miss name by observing ancient local peoples as Gods and so the name just stuck.) to planet Earth that tweak a few of the more natural develop primates DNA several times.
I think these researchers are missing something pretty obvious. They state that the majority of those showing this bend in the middle of the foot have a high BMI (meaning they're fat), maybe carrying all that extra weight has caused the "usually stiff ligaments that keep the foot from bending there" to become weak, therefore allowing their feet to bend where they shouldn't!
Excellent point sir, even those with lower BMIs could be accounted for by weak ligaments. To conclude it is an atavism is premature. Detailed analysis of the bone and ligament structure of those individuals is needed to determine if there are any anatomical abnormalities.