Flat feet, also called pes planus or fallen arches, is the condition in humans in which arch of the foot collapses, with the entire sole of the foot coming into complete or near-complete contact with the ground. In some individuals, an estimated 20-30% of the general population, the arch simply never develops, in one foot (unilaterally) or both feet (bilaterally). Horses can develop flat feet too, but that is beyond the scope of this listing. more...
The appearance of flat feet is normal and common in infants, partly due to "baby fat" which masks the developing arch and partly because the arch has not yet fully developed. The human arch develops in infancy and early childhood as part of normal muscle, tendon, ligament and bone growth. Training of the feet, especially by foot gymnastics and going barefoot on varying terrain, can facilitate the formation of arches during childhood, with a developed arch occurring for most by the age of four to six years of age. Although subject to debate among medical professionals, recent medical research indicates that arch support inserts and certain heel cups providing medial arch support, inserted into a growing child's shoes can facilitate the proper development of the longitudinal arch if the foot is held long enough in the correct neutral position while it is growing. The concern that this kind of support can actually result in a weakened arch or a dependency on arch support of this nature has been shown to be unfounded. However, there is little debate that going barefoot, particularly over terrain such as a beach where muscles are given a good workout, is good for all but the most extremely flatfooted (or those with certain flatfoot-related conditions such as plantar fasciitis). One medical study in India, with a large sample size of children who had grown up wearing shoes and others going barefoot, found that the longitudinal arches of the barefooters were generally stronger and higher as a group.
Although frequently a cause of worry by anxious parents who think the cosmetic appearance of a flat foot is not "normal" in their developing child, it is important to repeat that a flat foot is well within the normal range of foot types. Rather than focusing on trying to get an arch to develop in the child's foot, far better to focus instead on the child's (and parents') attitude toward the flatfoot condition, to encourage a healthy self-acceptance of being flatfooted, since a flat foot is still considered by some to be less than aesthetically "ideal". In fact, functionally, a study has shown the complete opposite: soldiers with a flexible flatfoot condition were actually less prone to injury than soldiers with a very high arch--because the flat, more pronating foot is more able to accommodate repeated or unusual pressure than a high arch, which is inherently a poor shock absorber. The high-arched soldiers had an appreciably higher incidence of stress fractures as a result of their inflexibly high arches.
As an example of the kind of attitude adjustment which may be more helpful than surgery, one flatfooter was quoted some years ago as feeling more "grounded", saying "I like the thought of having my entire sole making contact with the ground--it means there's more of me in contact with Mother Earth--plus, I just like the way it feels."
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