I’m not exactly sure of the reason, myself, but it could be that many people with flat feet (fallen arches) get sore feet from being on their feet a lot.
When I was 12, the family doctor told my folks that I had fallen arches, and recommended that I see a podiatrist to get the condition corrected with prescription arch supports. Over time, they would have forced a new curve or arch, into the soles of my feet.
For some reason that I couldn’t understand, my mother threw and absolute conniption fit at the idea, once we got home. She was so vehement about my NOT seeing the specialist, that even Dad wouldn’t overrule her.
Fast forward to the day I received my draft notice. Dad looked worried, because the US was at the height of the Vietnam War draft, most of the college deferments had been rescinded, and far too many Americans were dying, over there. Mom just sat there, in her chair at the dinner table, smiled at me, and said, “Don’t worry, honey. You’re not going anywhere, except to college.”
I had to go for my selective service physical, then, and Mom drove me to the Army base where I’d been ordered to report. After 3 hours waiting in line, it was my turn. The docs looked at my feet, and stamped 4-F on my paperwork. On the drive home from the base, my mother simply smiled at me and - years before it became “Hannibal” Smith’s catch-phrase, in “The A-Team” - told me, “I love it, when a plan comes together!” Turns out she’d decided, when I was 12, that the Vietnam war would drag on long enough to put her baby boy at risk, and she planned ahead. It cost me a lot of sore feet on Boy Scout hikes, but it kept me from playing cannon fodder in rice paddies.