ENDURANCE EVOLUTION

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Philippides got his place as a running legend tragically, but story has already been told somewhere. Long distance running has been with the human being even before we were called so, and it was of high importance in our evolution. Our closer evolutionally ancestors, the apes, are not designed to run long distances. Their bodies evolved for a forest environment, where this aerobic capability was unnecessary. For most animals the running capability specialization is based in short distances at a high speed, doing sprints, useful to escape or hunt preys. Consequently, most of mammals would be able to beat a full charged Usain Bolt at maximum speed (40km/h approx) during a short sprint. As bipedal specie we are unable to gallop, and consequently our pace is more similar to a trot, that let us run long distances, similarly to animals like horses or dogs. They are also capable of running at this trotting speed for long periods, but get tired easily at galloping speed. For distances like the marathon or longer, the human being would be able to beat any of these animals at a trotting speed.

And what makes us different?

Among these characteristics we could talk about our tendons, that work as powerful springs, storing the energy in a first instant, to release it later on. For example, the size of our Aquiles tendon is considerable bigger than the one in apes. Additionally, the biped position is more economical in energetic terms. Comparing with the chimpanzees, the closer animal species to us, they need as much as double the energy we need to cover a certain distance. There is also a redistribution of our centre of mass during the race, that is almost unused for walking, whose main duty is stabilization. Longer legs also mean less muscles need activation for every step, and the number of them needed to cover a distance. On the contrary of what could be expected the number of legs used doesn´t have any importance.

Nevertheless, there is a key factor, and is our thermoregulatory capacity. Running generates 10 times more energy, in heat form, than walking. Most of mammals must stop galloping after running a short distance because they are unable of cooling their core with quick enough to stop hyperthermia. On the other side, we are able to sweat, a highly specialized mechanism that allows us to cool quickly and run long distances. To do so we have evolutionary removed most of our body hair and increase the number of sweat glands.

Somewhere in Africa, around two million years go, and before developing tools for hunting, we had to compete in the savannah with other mammals simply for food. Lacking the physical attributes of other more powerful predators, our specialization focused on the ability to run long distances efficiently, allowing us to hunt, over running our preys, with a minimal risk.  This evolutionary advantage differentiated us of the other Homo that preceded. Where we will get from here is, at the best, only hypothetical.

Bibliography:

Economy and Endurance in Human Evolution
Pontzer H.
Current Biology 2017, R613–R621

The Evolution of Marathon Running Capabilities in Humans
Lieberman DE and Bramble DM.
Sports Med 2007; 37 (4-5): 288-290

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