Full transcript
0:23Do you know how a horse walks ? Even if
0:26it might seem complex , in reality , a
0:28horse's gait isn't that difficult to
0:29analyze . It’s just a staggered
0:31symmetry between the limbs on the left
0:32side and the limbs on the right . When
0:35the left hind leg moves forward , the
0:36left front leg moves forward as well .
0:38And when the right hind leg moves
0:39forward , the right front leg moves
0:40forward too . But in such a way that
0:42there are always at least three stable
0:43points of contact on the ground . Truth
0:47be told , it’s as simple as that . But
0:49where it gets really interesting is
0:50when you realize that , in fact , all
0:52four-legged animals walk the same way .
1:08And if they walk like this , it’s for
1:10a reason . A very simple reason : they
1:13are lazy . These animals have kept the
1:17instinct of least effort . Each muscle ,
1:19each bone , and each joint plays only
1:21the role that Mother Nature assigned to
1:23it . It is out of the question to waste
1:27energy while walking , so it must be as
1:29efficient as possible . Each step
1:32balances the body to prepare it for the
1:34next one . Which helps preserve their
1:38joints regardless of their weight . But
1:43does this also work for bipeds ? No ,
1:45that’s a real question , because if
1:47nature optimized the locomotion of
1:48four-legged animals , there must also be
1:50an optimal way of walking for those who
1:51, like us , stand on two legs . So what
1:54differentiates us from penguins or even
1:56ostriches , both of which walk on two
1:57limbs ? You’ve got it . Whether it's a
2:03penguin , an ostrich , or any bird , they
2:05literally walk crouching with their
2:06knees tucked against their ribcage .
2:09They belong to the " cheating biped "
2:10category , which includes plenty of
2:11other bipedal animals , so we can't
2:12really compare ourselves to them . So ,
2:15to find out if there is a balanced way
2:17of walking for humans , we just have to
2:19look at humans . So now , we are looking
2:36for the way humans walk , much like we
2:38saw with quadrupeds — a walk that would
2:40minimize effort while preserving our
2:42body and would be common to all . To
2:45answer that , there aren't many
2:46solutions ; you have to observe people
2:47walking . And honestly , what could be
2:49better than a crosswalk ? It's not the
2:54crosswalk itself that interests us ,
2:56because we can agree that observing
2:57every single pedestrian is impossible .
2:58However , this little green man will
3:00give us some major clues , because
3:01depending on where you are , he looks
3:03completely different . For example , here
3:04he is slightly hunched with his back
3:06leg slightly bent . If we change
3:08countries , he has an upright torso with
3:09both legs straight . In another region
3:11of the same country , his front leg is
3:12bent and his torso is tilted . Sometimes
3:15his torso is upright and his legs are
3:16in a wide stance . And we can even find
3:18him in animated form . Basically , each
3:20region represents its own way of
3:22walking . And knowing that there are as
3:24many ways to walk as there are regions ,
3:26the walk that Mother Nature intended
3:27for humans must be somewhere . In theory
3:32, bipedal walking is simpler than
3:34quadrupedal walking . Well yes , there
3:36are only two points of support to
3:36manage . So why do we observe so much
3:38variation in walks ? Because people are
3:40different . That's true , but it has
3:41nothing to do with genetics , culture ,
3:43skin color , gender , or whatever else .
3:46Some human beings have just kept the
3:47instinct for the path of least
3:48resistance , which means they will walk
3:49while wasting as little energy as
3:51possible . And once you have a sharp eye
3:52, it's striking . So , let's sharpen it .
3:56At first glance , when you see this man
3:57walking , nothing shocks you . It's what
3:59we can see regularly in the street and
4:01it's even what is recommended . However ,
4:03it's a series of falls . Basically , to
4:07move forward , he lets his body fall
4:08forward and just as he's about to fall ,
4:10he catches himself with his leg , which
4:12he places right under his body , putting
4:14huge stress on the knee since it's
4:15almost fully extended when it takes the
4:17weight . Since it's a series of falls ,
4:20the glutes no longer work to stabilize
4:21the pelvis , and the back overworks to
4:23prevent us from falling . So if nothing
4:25is working as it should and we're
4:26making the situation worse with every
4:27step , it's no wonder we have back pain ,
4:29actually . So , let's go see how those
4:32whose bodies aren't suffering walk . To
4:41start , we're going to India , in the
4:43Odisha region . Why Odisha ? Because ,
4:46like the small rural village of Bill ,
4:48Odisha has several small villages where
4:49all the inhabitants have excellent back
4:51health . So let's go see that . The first
4:54thing that strikes you in Odisha is how
4:55they carry their heads . Everything is
4:57about balance . The head is in line with
5:00the spine , the faces are projected
5:02forward , and the backs are strong but
5:04supple . Now we just need to see how
5:08that translates into their walk . The
5:13first thing to notice is that all the
5:15women in the video walk the same way .
5:17And before I tell you , do you see a
5:18difference from the walk we analyzed
5:20previously ? To make it simpler , let's
5:23focus on this lady . But it works with
5:25all of them . Since the torso remains
5:26upright thanks to the head carriage ,
5:28the leg must reach for its support to
5:29move forward , which directly results in
5:31bending the knee . The body weight never
5:33moves past the front leg . Thus , it is
5:40the legs that do the work , protecting
5:42the joints while allowing the back to
5:44rest . So yes , it is a walk of balance .
5:47Yes , it only engages the right muscles .
5:49But can we find it elsewhere ? Now that
5:50you have the eye for it , I'll let you
5:51judge . It is literally the walk of the
6:15instinct of least effort . We find it in
6:17rural areas , in places where people
6:18carry things on their heads . And in a
6:21France where people still had this need
6:22for balance every time , the body weight
6:28always kept behind the supporting leg .
6:36But today , this walk has literally
6:37disappeared from big cities . Support is
6:41weaker and much more fragile than
6:43before . What is the reason for this ?
6:46The first part of the answer is that
6:47the body follows the position of the
6:48head . If the head , for one reason or
6:50another , is constantly falling forward ,
6:52the torso will follow , thus forcing the
6:54legs to adapt . So the first thing to
6:57realize is that we are axis-based . The
7:01weight of life , surely . The second part
7:04of the answer is much more vicious and
7:06insidious , because it's another head
7:08falling forward . You can notice it , a
7:11knee extended instead of bent . When you
7:14know what you are looking for , it shows
7:15up again . But feet , do you know how a
7:22duck walks ? A duck moves from fall to
7:26fall because of its webbed feet . In
7:29water , they are excellent propellers
7:30that help it move forward . But on dry
7:32land , not using these propellers , this
7:34waddle is the only way it has found to
7:36move . In humans , the propellers are the
7:39toes , which only function correctly
7:41during the walk of least effort , much
7:42like the duck's feet only in water . But
7:44when that is the case , the foot is
7:46immediately recognizable because all
7:48feet that are working have the same
7:49domed shape at the top with a
7:51well-pronounced arch . Which means that
7:53with the walk of least effort , all feet
7:54that function correctly look the same .
7:56So to know if walking has always been a
7:58series of falls or balance , you just
7:59need to look at the shape of the foot ,
8:01and there's no need to analyze every
8:03person , because just like the
8:04pedestrian crossing , humans have always
8:06liked to represent themselves . K. Are
8:31you passing by ? Ah Don't hesitate to
9:22like if you haven't already , and see
9:24you next time .