Flat feet once were considered enough of a disability to bar people from entering the armed forces, but they now are considered a normal variant of human foot shape. Adults may develop a condition called pes planovalgus, or fallen arches or, in some cases, children simply don’t develop an arched foot. Common thinking held that corrective shoes in children might develop an arch, but studies among people who regularly go barefoot suggest shoes on young children are more likely to promote flat feet rather than to cure them.
Most infants begin with flat feet, which should be no cause for concern among parents. Arches develop as children learn to walk and as less baby fat covers the feet. For many children who don’t develop an arch, this isn't a problem; however, in some cases, the flatness can be associated with other feet problems. In particular, children who have anklebones that lean inward may require corrective shoes. Feet that are inflexible and painful may be caused by a condition called tarsal coalition.
Tarsal coalition occurs when two bones in the foot fuse together. This results in a highly inflexible foot and pain during walking, and shoes with arches may make the condition even worse. Children who have flat feet and complain frequently of foot pain should be evaluated by a medical professional, and normally undergo surgical treatment in their pre-teen years to correct the fusing. Surgery needs to be cone while the foot is still growing in order to be effective.
Feet that become flat in adulthood may be called fallen arches. This often happens to women who are pregnant and others who are carrying more weight. Adult-acquired foot changes tend to be permanent, but they may not be related to any specific complications. When this condition does cause painful walking, using specially designed orthotics in shoes and performing foot exercises often helps. Surgery can correct a flat foot, but it is seldom the treatment of choice.
While flat feet were once considered a sign of poor health, the opposite may in fact be true. Most top track stars have feet that are very flat. People with a higher arched foot are four times as likely to turn or sprain an ankle. Feet that are flat are no longer a reason to be excused from army service, and in many cases, create no problems for the person who has them.