Adaptaciones de los homíninos que los hicieron corredores más eficientes. Transcript: Speaker 1 If you do the calculations correctly, and you look at the scaling relationships, humans are actually just as expensive as we should be for a typical animal of our body size. So went you correct for body mass. So back in the day, it was thought that humans were really costly. In fact, there was a study, the only good study that had been study the e was done on a single individual. I think he was from italy. And he must have been a really bad runner, because in that study, this one guy came out asbout as efficient as a penguin. I think you can imagine that penguins aren’t really great runners. But more recent studies have shown that actually, if your body mass on the ax axis against the cost of transport, humans fall right on the line from mammals. So we’re actually just where we should be. We’re not inefficient. We are very costly, though. And thestuna yo of walking, what’s interesting is hat the animals that we evolve from, chimpanzees, they’re very costly. So chimpanzees spend about twice as much energy to move a kelo of their body at a given distance human. Speaker 2 So there’s an argument here for small feet and big hips making running cheaperwell, it’s not big hips, but it’s, well, mi mechans get abitt complicated. Speaker 1 But most animals run on their toes, right? Everything about dogs, horses, they run on their toes. But we’re primates, right? Primates have these big, ugly, flat plantigrade feet, right? And so but big feet are a problem because you can break them when you run, because though you have really high torks, you have high forces that act over large moment arms too. So, and chimpanzies have really long toes. And australiapiths like lucy have really long toes. But when shou get to genus homo, the toe length gets really shorter. And like, why would that be the case? Well, it actually turns out hasn’t very no effect on walking. You can walk with long toes and its just fine. But when you start running with long toes, it’s a nol serious problem. So we shortened our toes. And that’s clearly an adaptation for running, again, because we’ve proved by mechanically it’s not really very relevant to walking. And also the other thing, as we added an arch to our foot, right? So, chimpases have flat feet, and there are humans to day who have flat feet. About a third of americans, for example, have reasonably flat feet. And the problem with flat feet is not so much walking. As you can tell, most of those americans are able to walk just fine. But the arch of the foot is a spring that in running. And running is a spring like gait, and walking is not. Walking is basely a pentular gait. So adding that spring to our feet was also a really key adaptation that really only makes sense for running and has really nothing to do with walking. Hip’s a another interesting issh. I mean, i o go on. Look, theyre are adaptations, literally, from our toes all the way up to our heads, that help us become better runners. Long achilles tendons, for example, which are key springs. Or chimpanzees have achilles tendons that are like centmeter long, maybe less ite. And it were, as humans, we have these really half the length of your shank, right? And they act as an important spring. We have hips that are mechanically advantageous, not just for walking, but also for running. It reduces the torks and hip. But importantly, we els have waists that enable us to move our thorax, our chests, independently of our hips. So when you run, right, you twist your upper body. Chimpanzees can’t do that. When they rotate their hips, their whole upper body has to rotate with them. But we have this zone of separation between our hips and our thorax that enables us to twist so that our bodies can bestly point forward as we’re rotating our legs as we’re running. And we also have another zone of separation between our thorax, our shoulders and our head, which so chimps can’t do. So when the chimps rotate their thorax, their head rotates with their thorax. So we’ve dropped down, or we’ve lost a lot of the muscles that connect our upper body with our heads. Those are great musclesfor climbing. We lost those, right? But they enable us to keep our heads still while we rotate our thorax. Fron the running. (Time 0:10:01)
adaptación correr eficiencia evolución homo_sapiens simios
adaptación correr eficiencia evolución homo_sapiens simios
The Evolution of Running • Walking is a pentagonal gait, which is different from running which is a hexagonal gait. • The adaptations that make walking better for running include a spring in the feet, a long achilles tendon, and a hip that is mechanically advantageous for running. • The main difference between walking and running is that walking allows the thorax to be moved independently of the hips, while running requires the entire upper body to rotate with the hips. Transcript: Speaker 1 Walking is basely a pentular gait. So adding that spring to our feet was also a really key adaptation that really only makes sense for running and has really nothing to do with walking. Hip’s a another interesting issh. I mean, i o go on. Look, theyre are adaptations, literally, from our toes all the way up to our heads, that help us become better runners. Long achilles tendons, for example, which are key springs. Or chimpanzees have achilles tendons that are like centmeter long, maybe less ite. And it were, as humans, we have these really half the length of your shank, right? And they act as an important spring. We have hips that are mechanically advantageous, not just for walking, but also for running. It reduces the torks and hip. But importantly, we els have waists that enable us to move our thorax, our chests, independently of our hips. So when you run, right, you twist your upper body. Chimpanzees can’t do that. When they rotate their hips, their whole upper body has to rotate with them. But we have this zone of separation between our hips and our thorax that enables us to twist so that our bodies can bestly point forward as we’re rotating our legs as we’re running. And we also have another zone of separation between our thorax, our shoulders and our head, which so chimps can’t do. So when the chimps rotate their thorax, their head rotates with their thorax. So we’ve dropped down, or we’ve lost a lot of the muscles that connect our upper body with our heads. Those are great musclesfor climbing. We lost those, right? But they enable us to keep our heads still while we rotate our thorax. Fron the running. (Time 0:12:14)