This seems like a flawed argument. By the logic in this article, wouldn't horses or cows, which weigh multiple times what a human does, have to have stocky rather than slender legs?

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ndr 3 hours ago | parent | next [-]

1. They stand on 4 limbs, rather than 2.

2. That would be assuming that human legs are sized at the max capacity they can carry, which is not true.

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necovek 2 hours ago | parent [-]

Regarding 1, horses in particular are known to jump off two hind legs and land on their two forelegs, putting a lot more force on them than their stationary weight.

On 2, I believe that's the GP's point too — human leg bones (or horses') can obviously take a lot more than their standing/walking/running weight.

	▲	ndr 2 hours ago \| parent [-]
		Agree re 1, but point 2 still stands. They can take more stress than standing, but the scaling law is still there. If you scale linearly height/section the max stress won't scale linearly because the weight will scale cubically.

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maxerickson 2 hours ago | parent | prev [-]

How big is big?

The practical limit for bipeds is probably ability to survive a fall to the ground. It's not super common, but enough people die simply from falling from standing.

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schoen 2 hours ago | parent [-]

On the other hand, people can learn to fall more safely (like in gymnastics and martial arts). Maybe some version of those skills could somehow become instinctual, as maybe the corresponding thing is in cats?

	▲	maxerickson 2 hours ago \| parent [-]
		I guess if there were resources that were much more available to these agile tall people that might happen.