Spending your life exclusively on flat terrain is not natural. It’s also a little weird that so many people, including myself, suffer from lower back pain.
My lower back pain started when I was a teenager. In the summer right before university, I worked in the Yukon as a soil sampler. Basically I hiked around remote mountains and collected bags of dirt. The dirt was then sent off to a lab in the hopes of finding gold.
Just before I left, I had a horrible flare up in my back. I was terrified of getting to the Yukon and being unable to do the job. But once I started hiking around the mountains, my back pain disappeared overnight.
Years later I realized the doctors and physiotherapists I had visited were full of shit. They told me to stop going to the gym because of my “bad back.” My "bad back" was actually just hip immobility. I've worked on my hips a lot since then, and my back pain has not returned. All I had to do was strengthen those "tiny" muscles around my hips and pelvis.
"Sitting too much" is the usual suspect for tight hips, and there's plenty of reason to believe that assessment.
But when I was 18 and hiking around the Yukon, was it the lack of sitting that made me feel so good? Or was it because I was constantly walking around on uneven terrain which forced me to use those "tiny" muscles around my hips?
It seems unnatural that modern human life is spent almost exclusively on flat terrain. Both urban and rural environments are based around flat surfaces. Flat roads, flat fields, flat sidewalks, flat floors. The most common obstacle we face is stairs, but those are flat too.
I bet rates of back/hip pain would drastically decrease if we all spent 15 minutes/day walking on uneven surfaces. Anyway, here's a carefully selected Reddit thread that agrees with my hypothesis: My thru-hike cured my multi year back pain
Thank you to Joel Christiansen for contributing to this article on Foster