[quote]Schwarzfahrer wrote:
We certainly aren’t ‘born to squat, bench and clean’, on this we can agree.
But your list is still wonky in my opinion.
It is similar to what vegans write in defense of their herbivore theory.
in other words, just because we can do some things or geown some organs doesn’t have to mean we are exclusive endurance hunters.
Some facts in your list are crazily distorted.
E.g. (Barefoot) walking though the woods is NOT possible with a “virtually inactive” achilles tendon.
or
the account of various anatomical facts- yes we have a nice ass that chimpanzees lack. Which is one big part of the reason they cannot walk upright very well and we can.
What has that to do with the endurance hunting theory?!
For a sound paleontological theory, I’d like to see a timeframe.
Are we talking about a human ancestor? If so why should we care?
He certainly wasn’t successful enough to switch to a full-fledged carnivore. Which is strange, given his superexpensive hunting tactic (see my last post).
Or are we talking about homo sapiens sapiens?
Why did he venture into many non-endurance huntable regions so fast, then?
Why do practically all native tribes today hunt with ridiculously minimal effort? In contrast, I’ve read about one african tribe who supp. engages in endurance hunting.
There are other adaptions that are even more amazing.
Which animal can build and hurl a killing/stunnung device with such precision?
That takes some serious calculation.
So we are ‘throwers’, maybe?
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Rethinking this I think we agree more than disagree. I certainly do not think we have evolved to be exclusive endurance hunters. But we have adaptiations that appear to only be relevant in running.
The point of the achilles, is that it is only active in walking at toe off. In human locomotion, the Pendular mechanics of walking, make the calcaneus very important for initial contact. As I explained earlier, running is not Pendular. In order to take advantage of achilles tendon stretch mechanism, it must first stretch, to gain the potential kinetic energy. This does not occur in walking. Only in running, and primarily (achilles, iliotibial can still stretch from limb complience as a result of vertical displacemnt) only in mid to forefoot strikes. WHich is where Martin Rooney, was wrong a little while back when he stated something to the effect of “then why are we supposed to run on our heels?” …that’s it, we arent, (well sort of). The forefoot should touch down first followed by the heel then toe off again. We work like springs, storing and releasing energy. (the plantar arch returns 17% more energy in running than in walking) As I alse pointed out earlier this is where the “U” shaped Curve of the metabolic cost of locomotion comes into play. To a certain point walking fast is more costly than jogging slow, which is why most humans voluntarily switch to running around 2.3-2.5 m/s. This takes advantage of the mass-spring mechanics of jogging. And to fully do so, requires anatomical features like long achilles tendons, longitudinal arches, IT band, lower shoulders, etc.
The point about our “ass” is that it’s development is directly proportional to the velocity demands of running in Bipeds. The butt is not very active if it all in walking, so why did we develop big butts.
Just taking a look at all top runners, what do they have in common, long achilles, big ass (sprinters, more than endurance athletes). Some might have veriations, but these things are key in running.
Enter toes, as I mentioned earlier longer toes= greater force which in turns means a greater metabolic cost. So what happend to our toes? they shortened.
In Australopthicus, the gelnoid cavity is oriented cranially, which results in shoulders that are elevated, which would aid in climbing, but whould have no obvious hiinderance to bipedal walking, but would clearly impede with the counter rotations on the transverse axis that occur when running.
Nuchal ligament, absent in chimps and australopithecines, is a stabilizing feature with greater use in running, not walking.
These are just a few of the adaptations, that have no other reason to exist other than for running.