The Human Foot Is a Design Disaster - Cheddar Explores

this guy made history in 2012 for being the first amputee runner to compete in the Olympic Games its Oscar Pistorius who you might also know for murdering his girlfriend but this is a video about feet so let's set that aside Pistorius had to fight for his right to compete in the Olympics by proving to officials that his blade-like prosthetic feet didn't give him an extra advantage over athletes running on regular old flesh feet there are other blade runners fighting the same fight behind him the German long jumper Marcos rim was barred from competing in the Rio Olympics the college track athlete hunter Woodhall had to make the case to the NCAA and Paralympian Blake Leeper is gearing up for the same fight to compete in the 2020 Olympics and it all makes you wonder why does the foot designed in a lab look so different from the biological human foot it might be because the human foot is kind of a design disaster podiatry is a five billion dollar industry a majority of Americans will experience significant foot pain at some point in their lives and as many as 10 percent of us will experience inflammation in the band of tissue along our arches otherwise known as plantar fasciitis why though weren't humans evolved to walk long distances and isn't walking upright on two legs the trait that first separated us from other primates so why hasn't natural selection selected a cooler better less injury-prone foot for us some theories posit that we're so plagued by foot problems because we evolved to walk barefoot out of nature over soft sweet earth but now we've thrown off the delicate biomechanical balance of our feet by wearing big mushy cushiony tennis shoes meanwhile our bones take a beating from walking and standing on super hard surfaces like concrete but other researchers say it goes back way further than that jeremy de silva is an anthropologist who studies human evolution and argues that foot problems exist way back in the fossil record fossils show evidence of osteoarthritis and compression fractures and flat arches which means foot pain millions of years ago DeSilva makes a convincing case that the real source of our foot problems is the janky design as I mentioned earlier what we're looking at are our paper clips and duct tape our primate ancestors spent most of their time in trees our feet then were originally meant for climbing and grasping but four million years ago and possibly earlier some Apes started dabbling in bipedalism experts haven't agreed on why hominins developed this trait perhaps it was a more efficient way to travel while scavenging for food or maybe it was to enable persistence hunting tracking prey over such long distances that they became overheated and simply laid down from exhaustion no weapons required whatever the reason bipedalism is the defining trait of humans going bipedal involved some painful and atomic ultradox including everything from where the spine attaches to the skull to the angle of the femurs and of course the shape of our feet let's talk mechanics a foot is a propulsive lever it needs to be stiff enough that we can push off the ground and propel ourselves forward but it needs to be elastic enough to store the mechanical energy that's generated each time the foot strikes the ground that's how designers ended up with this blade shaped for athletes the human foot on the other hand has 26 bones 33 joints and over a hundred muscles tendons and ligaments that's because it was built for grasping all those joints let it flex so it's not inherently rigid enough to give us the propulsive power we need here's what had to change back when we were climbers our big toe used to be opposable like our thumbs but to help make the foot more rigid it became shorter stiffer and in line with our other toes and we developed arches to absorb the force of impact each time our foot hits the ground our ligaments got thicker to help hold all these small bones firmly in place bipedal locomotion is a notoriously complex mechanical engineering puzzle that scientists have been working on for decades and in the case of human feet you could say natural selection is still in the early design phase DeSilva uses the ostrich as an example of a foot from the natural world that resembles the prosthetic blades that were perfectly designed for running on two feet but he also points out birds have a big bipedalism head start just look at their ancestors they've been bipedal for 230 million years while we've only been bipedal for about five million and a big take away from his talk natural selection isn't selecting from an endless menu of options rather it's a constant series of small modifications to the original design so in our case it slowly modified flexible grasping hands into more rigid propulsive levers which left us kind of vulnerable to some aches and pains but considering our feet are modified a pans they do a pretty good job and considering where the most successful primate neh mammal neh species on the planet it's a pretty decent compromise thanks for watching if you're super interested in the scars of human evolution you can see the whole talk on Boston University's YouTube page if you liked this video hit the bell icon so that you can get notified each time cheddar posts a new video thanks again we'll see you next time

Channel: Cheddar

Views: 2,436,078

Keywords: Cheddar, cheddar explores, the human foot, human foot, feet, medical, the human body, podiatry, podiatrist, evolution, oscar pistorius, foot pain, bones, human structure, foot bones, foot injuries, evolution of walking, explainer, explainer video, ankle, foot, plantar fasciitis, health, toes, heel pain, ankle sprain

Id: kd-FZptfGUE

Length: 5min 36sec (336 seconds)

Published: Thu May 30 2019