system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why exactly are back pains so common as people age?

Why is it such a common thing, what exactly causes it?   
(What can a human do to ensure the least chances they get it later in their life?)
gpt
Keep in mind that humans are pretty unique in our vertical torso set up. Most other animals have the weight of their bodies relatively evenly distributed across 4 points. We put all the weight of supporting our upper half on our lumbar. Even in the best of conditions, problems are bound to happen.