system
Given the following post, respond as if you're commenting on Reddit:
human
Why are some people flat-footed and what are the known disadvantages/advantages of this trait?

I asked this before, but after no response, decided to delete and rephrase my question. I know the US military will not accept flat-footed soldiers. They mentioned increased fatigue over long distance, but their research was inconclusive. Considering me and most of my living relatives have this condition, I'm interested to hear from any evolutionary biologists, medical specialists, genetic researchers, and any other qualified individuals about the prevailing theories surrounding the possible reason for the selection of this gene and the potential physical ramifications of this condition. I hope I've been more concise this time around and I appreciate any info.
gpt
Orthotist here: We naturally pronate our foot during gait as it helps to absorb shock and helps us to balance as our other foot leaves the ground. Babies pronate more due their bones being a little nubby. this allows for better shock absorption protects the developing hips and it gives better balance. Most spontaneously develop a longitudinal arch at around 10 years. Some though, develop ligament laxity or do not develop the muscles inside the feet adequately from learning to walk this way, and continue to pronate all the way through foot development. OR you have twisted tibias... The unusual loading of the joints (sub talar, talocrural joint) can cause osteoarthritis in due time. People with flat feet often get lower back pain too, as the foot is not as good as shock absorption as a higher arched foot....I tried to weed out a lot of the jargon, hope that answers everything!