Maybe you’ve had this experience: You walk out to your car in the morning before work, or in the parking lot on your way home, and your heart sinks when you see one of your wheels flush with the ground. Of course, while unexpected flats are an especially unwelcome nuisance, even healthy tires can slowly deflate over time. Something similar can happen with your feet, specifically your arches.
Flat feet is most common in kids under 6 years old; at that age, bones and joints are soft and flexible enough that simply their own body weight is enough to flatten the arch all the way to the ground. Most grow out of it as their bones, muscles, tendons, and ligaments strengthen and become more rigid. However, even adults who at one time formed healthy, medium arches can wind up with flat feet after injuries, illnesses, or just decades of wear and tear. When it happens, it’s called adult-acquired flatfoot, to distinguish it from the “pediatric” version.
Genetics are the primary culprit for those who simply never developed an arch when they were growing up. By contrast (and like our flat tire analogy), adult-acquired flatfoot may have one (or more) of several underlying causes—some preventable, some not. These may include:
- Both traumatic and overuse injuries, which can weaken bones and stretch and pull connective tissues, causing the arch to collapse. Footwear that doesn’t fit or puts too much strain on your feet can also contribute here.
- Diseases that result in loose connective tissues, such as joint hypermobility or Ehler-Danlos syndrome, or those that damage muscles and nerve, like muscular dystrophy or cerebral palsy.
- Obesity. Every pound of weight you carry may add 2-3 points of force (or more) on your feet when you take a step. That much pressure on your feet can gradually lead to sagging arches.
- Aging. Weakening tissues are a normal part of the aging process, and over time it may become more difficult for tendons to maintain the arch’s rigid shape.