About Your Feet
There are 28 different bones in the human foot that contribute to the biomechanics of walking and running. People who stand a lot during the day often complain of having tired feet, but these joints in your foot take on the weight of your entire body when you walk and up to five times your body weight when running.
When we walk, our feet go through a repetitive motion where the arch falls or flattens out and then gets elevates and this allows the foot to “lock” and “unlock” when going through the gait cycle. When the arch collapses, the foot “unlocks” and allows us to adapt to uneven terrain like being barefoot in a field. We evolved to have the ability to unlock the foot and allow it adapt to prevent injury. We did not evolve to walk in shoes on hard flat surfaces like cement sidewalks and this can be the source of our foot problems. (Incidentally, cultures where the population does not wear shoes do not have the same foot problems that developed nations do.) When the arch elevates, it “locks” the foot in place to allow us to transmit force more efficiently. When you are walking or running, you need to push off of a stable, rigid surface to propel yourself forward effectively.
The root of most biomechanical foot disorders is that the arch falls too much or over-pronates when the foot is weight-bearing. The vast majority of the population are over-pronators. These problems with the biomechanics of gait can easily be corrected by custom foot orthotics.