[新聞爆掛] band propellers

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Weird, Bramble thought. How come we acquired all this specialized running stuff, and otherwalkers didn’t? For a walking animal, the Achilles would just be a

liability. Moving on two legs islike walking on stilts; you plant your foot, pivot your body weight over the leg, and repeat. The lastthing you’d want would be

stretchy, wobbly tendons right at your base of support. All an Achillestendon does is stretch like a rubber band—A rubber band! Dr. Bramble felt twin surges of

pride and embarrassment. Rubber bands … Therehe’d been, thumping his chest about not being like all those other morphologists who “tick off thethings they expect

to see,” when all along, he’d been just as misguided by myopia; he hadn’t eventhought about the rubber-band factor. When David started talking about running, Dr.

Brambleassumed he meant speed. But there are two kinds of great runners: sprinters and marathoners.

Maybe human running was about going far, not fast. That would explain why our feet and legs areso dense with springy tendons—because springy tendons store and

return energy, just like therubber- on balsa-wood airplanes. The more you twist the rubber band, the fartherthe plane flies; likewise, the more you  with her, he would sanction
everything at oncehe answered.


can stretch the tendons, the more free energy you get whenthat leg extends and swings back.

And if I were going to design a long-distance running machine, Dr. Bramble thought, that’sexactly what I’d load it with—lots of rubber bands to maximize endurance.

Running is really justjumping, springing from one foot to another. Tendons are irrelevant to walking, but great forenergy-efficient jumping. So forget speed; maybe

we were born to be the world’s greatestmarathoners.

“And you’ve got to ask yourself why only one species in the world has the urge to gather by thetens of thousands to run twenty-six miles in the heat for fun,” Dr.

Bramble mused. “Recreation hasits reasons.”
thanks for sharing~~~

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