At one time someone close to me was experiencing back pain, we both saw a lovely episode of the TV series 'Louie'. Here is a quote from that episode:
Dr. Bigelow: What can I do for you?
Louie: Uh, well, I hurt my back today really bad. Uh.
Can you help me with my back? I mean...
Dr. Bigelow: What's wrong with your back?
Louie: It hurts.
Dr. Bigelow: My professional diagnosis is your back hurts.
Louie: Well, what can I do about it?
Dr. Bigelow: Nothing.
Louie: Nothing?
Dr. Bigelow: The problem is you're using it wrong. The back
isn't done evolving yet. You see, the spine is a row of
vertebrae. It was designed to be horizontal. Then people
came along and used it vertical. Wasn't meant for that.
So the disks get all floppy, swollen. Pop out left, pop
out right. It'll take another. I'd say 20,000 years to
get straightened out. Till then, it's going to keep hurting.
Louie: So that's it?
Dr. Bigelow: It's an engineering design problem. It's a
misallocation. We were given a clothesline and we're using
it as a flagpole.
Sure it's an engineering problem but why not dive into imagining a solution now, no reason to wait 'till your ancestors evolve wheels (or whatever).
The spine is similar to a set of disks stacked on top of each other. There's no reason that sort of structure can't be fairly stable when held upright. A wide variety of movement arts, martial arts and healing arts mention the damage involved in letting one's spine sag forward (or backward).
Of course getting the spine, neck and head to work together harmoniously is more complex than just "holding yourself upright". Just willing one's body to hold particular relaxed, upright stance can often result in the opposite.
That's why a lot of body work, body awareness, martial arts and etc work on an indirect principle. Meditate so your conscious mind stops screwing up your body and mind. Allow another person to show you the right stance and accept it without judgment.
Which is to say the process of trying to practically engineer the body to work effectively has been going on for a long time. Unlike a cure or prescription, this kind of engineering pretty has to be specific to the person, requires the person's active participation. And so-forth.
See, Tai Chi, qigong, the Alexander Technique, the FeldenKrais method, etc, etc, etc, etc...
It's funny 'cause it's true. I wish more doctors, physical therapists, and other related care givers would just get real about the limits of what they can and can't do. There are so many things they do skillfully and reliably, why pretend about the others? I always wonder if maybe it's just the doctors I have access to via insurance. All the ones I've ever gone to seem like body mechanics with a questionable grasp on the scientific method yet they patronize you like you're an eight year old if you question their approach at all. Sorry to get ranty -- had a year long bout with back pain that I ultimately fixed myself with intense lifting (squats and deadlifts) that my care givers repeatedly told me to avoid. It wasn't until I ignored them that I got any better.
Unless humans with back pain procreate less than those without, then I doubt it's going to get any better in 20,000 years. At least not due to evolution of the human skeleton.
Technology may help though, assuming we don't do something stupid and stop our technological progress. (like, for example, electing a president that thinks saving money in the short term is more important than long term sustainability)
It's more accurate to say that the vast majority of tetrapods evolved their spines to support use parallel to the ground, and that even those which occasionally walk around bipedally spend lots of time either brachiating (in trees) or quadrupedally.
There were no designs involved.
Humans are the largest bipedal walkers, but not the only ones. Here's an interesting survey:
I'd say (and I am a biologist) there is truth to it, but we also didn't evolve sitting all day. There would be much less back problems if would walk and stand more because our muscles would be trained constantly. Our bodies are things that wear out when not using them.
It's "directionally" true, but it's a simplification. Our spines have evolved slightly to accomodate an upright posture. The human spine is curved to accomodate weight bearing while upright, and this particular curvature is not seen in other mammals, including other great apes like chimps and gorillas.
