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My question is, how do we make humans more able to resist falls(not just free falls, also normal ones and from a "medium" height, 2-10 meters) and be able to move afterwards, at least for the jumps on the lower end. So "action movies"-like jumps should be possible and leave the jumper not stuck on the ground like a sponge.

Some ideas I've gathered from previous answers or elsewhere:

  • Lighter humans, this old essay here is pretty famous and talks about how smaller animals have it easier in terms of falls given the square-cube law, obviously if we keep humans the same size we have to make them lighter. This is an easy solution, although I'm not sure about the details of such a change, if humans weighted roughly 2 times less, what kind of falls would they be able to survive? As far as I can see, human femurs can resist 30 times the human weight and the terminal velocity is 66m/s for real humans, obviously if humans weight 2 times less the second values will be lower but what would it translate to? It seems to me the bones would still break.

  • Stronger bones, bones not breaking would help a lot, obviously bones that are too stiff and let the rest of the body take all the force is bad, but I imagine this shouldn't be a unsolvable dilemma, can't bones be stronger while retaining their relative elasticity?

  • More cartilage, I'm not sure where there is space to place it while not impeding normal function but I imagine if you can afford some, it wouldn't hurt AFAIK. Also if cartillage can fully regrow it would allow people to rationally risk bad falls to do whatever they need to do at the moment.

  • More internal organ cushions, if we remove some vestigials or semi-vestigials organs and use their space to put some cushions or well placed fat, can it help organs to not become a soup in the process? What is the most worth protecting?

  • Better internal structure, maybe placing vital veins,arteries and nerves in places less likely to be perforated or broke by moving organs/force. I'm not an expert at all. I know the human bodies has some bad designs for some pathways but other than that I'm not sure how much room for expansion there is.

  • Better feet, the video here and the scientist behind the idea say that human feet are especially well made for walking, regardless of that discussion can human feet be tweaked to absorb more force in such falls? Maybe fusing some bones that don't move or putting cartilage or fat everywhere, I'm out of ideas on this front, lol.

I'm looking for some general but concrete ideas, I want humans to look as much as possible like humans on the outside but you can go relatively wild with internal organ layout and so on.

Thanks in advance!

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    $\begingroup$ Stories told by older guys tell me that part of the training for the conscripts back in the days was climbing and jumping a 10 m high wall... so apparently it's already possible $\endgroup$
    – L.Dutch
    May 7, 2020 at 9:22
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    $\begingroup$ how do we make humans more able to resist falls Train them in parkour $\endgroup$ May 7, 2020 at 9:22
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    $\begingroup$ The only reason falls kills us is the direction of impact on the bone . Bones can tollerate a lot of pressure straight top to down, but little to no torque or horizontal pressure. Our bones are so frail to torque and horizontal pressure you can break your own arm by playing Armwrestling and its quite common. So just teach your creatures how to fall properly. $\endgroup$
    – user75545
    May 7, 2020 at 9:32
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    $\begingroup$ @Kyu ummm... The only reason falls kills us is the direction of impact on the bone I wouldn't go so far to claim that's the only reason, but yes, with correct landing techniques and a clean landing area, a 10m fall is not necessarily debilitating much less fatal. $\endgroup$ May 7, 2020 at 9:46
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    $\begingroup$ Accidental falls from 10m and uncontrolled landing, yes, are fatal. Controlled falls and landing, not necessarily. I thought you are asking about "action movies"-like **jumps** should be possible and leave the jumper not stuck on the ground like a sponge. which is quite a far... ummm... jump from "any human must survive a fall from 10m" $\endgroup$ May 7, 2020 at 11:51

4 Answers 4

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Meet Graham - The only person designed to survive on our roads

Hint - hover over the photos, you'll see the internal structure

A selection of attributes pertinent to the question

  1. Graham’s brain is the same as yours, but his skull is bigger with more fluid and more ligaments to support the brain when a collision occurs.

  2. Graham’s skull is a lot bigger, it’s almost helmet like and it’s got these inbuilt crumple zones that would absorb the energy on impact.

  3. the neck uses one of our existing elements of protection, the ribs, and extended them up to reach the skull

  4. Graham’s knees have movement in all directions. His joints are fortified with extra tendons to give added flexibility

  5. An extra joint in Graham’s lower leg gives him a spring loaded jump - more tendons will also help dissipate the energy of the landing and/or help with redirecting it (transitioning from a fall into a roll)

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  • $\begingroup$ The problem with Graham is it goes strongly against my first point, and increases tremendously the weight of the entire being while not really making it have more drag. But the last 2 ideas are good, I wonder if they can work with normal sized humans though. $\endgroup$
    – Blirk
    May 7, 2020 at 10:47
  • $\begingroup$ Also a larger fluid filled cavity actually makes brain injury easier. what graham really needs is more connective tissue in the brain itself so stress of deformation is not taken by the cells with other functions. $\endgroup$
    – John
    May 7, 2020 at 15:29
  • $\begingroup$ @John What could this connective tissue be made of? $\endgroup$
    – Blirk
    May 7, 2020 at 20:10
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    $\begingroup$ There are more than a dozen large nerves run from the brain to the skull, so you can't have the brain moving around without tearing said nerves. It is often claimed that the CSF acts as a shock absorber but that is only for MINOR impacts, against stronger impacts is does the opposite, which is why animals which commonly receive skull impacts, like woodpeckers evolve less CSF not more. asknature.org/strategy/head-cavity-protects-brain To use your analogy the egg in the jar is protected from a little shaking but not say, dropping the jar. $\endgroup$
    – John
    Sep 24 at 11:57
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    $\begingroup$ some of the ideas are good others make no sense, the redesign to the legs makes no sense, but neck ribs are actually normal for everything but mammals. the knee joint actively encourages dislocation, which is incredibly stupid, its like saying the skull can be crushed so we should make it collapsible, completely forgetting the function of the joint. the built in air bags create a massive new point of infection, just awful. thicker skin is a good idea, but humans actually should have thicker skin than we do but constant bathing thins the skin. the protection of the skull and face are fine. $\endgroup$
    – John
    Sep 25 at 14:50
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You'll need them to have another pair of legs so they can tack on the movement without pause. They could transition with their arms as they are, but that wouldn't look very "action moviely".

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  • $\begingroup$ In trying to imagine what you mean the scenario seems very goofy to me. $\endgroup$
    – Blirk
    May 8, 2020 at 10:59
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Prosthetics

You can't break your ankles if you don't have ankles! Falling from 2-10 meters is harsh, but not when you have giant springs attached to your legs. Sure cutting off your feet to fit the prosthetics is a real drag, but this is worldbuilding; where human augmentation is just the beginning and paying $15,000 each to leap off tall buildings in a single bound is a survivable affair.

The flex foot cheetah, (known as blade runners in the popular press), is a prosthetic human foot replacement developed by a biomedical engineer. It and similar models enabled Oscar Pistorious, "the fastest man on no legs", to run more efficiently than any naturally gifted human using 25% less energy than runners with completely natural legs running at the same speed and less vertical motion combined with 30% less mechanical work for lifting the body. However, even this great advantage was not enough for Pistorious to outrun the South African Police, who will be holding him in prison for at least 6 years.

Prosthetic image thanks to: https://en.wikipedia.org/wiki/Flex-Foot_Cheetah

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Are we talking normal falls, or accidents?

If the first, then you need a single mechanism to absorb impacts; not being an unforeseen accident, the body has the time it needs to orient itself to bring the mechanism to bear.

Added flexibility and faster reflexes can reduce the number of possible accidents that prevent the shock absorber from working properly.

The shock absorber itself is just a different knee and pelvis joint, with stronger tendons and muscles, and a reinforced leg bone structure. Let's also add a shock padding to the soles of the feet for good measure.

You will almost certainly require some highly specialized reflex arches to manage the impact: the time involved is too short for conscious thought or even trained reactions (cerebellary routines) to kick in, and properly controlling muscle tension will increase performances significantly.

Upon impact, the lower body will simply undergo a controlled compression into a crouch.

Falling from a height of 20 m yields an impact velocity of 20 m/s; legs and lower body compression gives us, optimistically, one meter of dampening. To shed 20 m/s in 1.0 meters we need an acceleration of (2020)/(9.8121.0) = about 20.1 G and we need to sustain it for 20/(20.19.81) = about 0.1 s.

While 20G is more than an ordinary man can ordinarily survive intact, it's not outside the realm of possibility. Adding a biological spring shock absorber should be more than enough.

(I don't think it's really doable to increase this too much - I have played with the numbers, I was hoping to reach the impact velocity of 55 m/s, because that would have meant being able to fall from any height whatsoever, but damage increases with the square of the impact velocity, and 55 m/s is almost eight times harder).

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