Flat-footedness Has to Do With Walking, Not Appearances
Published: December 16, 1990
To the Editor:
"The Maligned Flat Foot: Some See an Advantage" (Health page, Nov. 22) questions the old idea that to be flat-footed is to be clumsy and inadequate. Indeed, the conclusion that under certain conditions to be flat-footed could be a functional advantage over being high arched is reasonable. However, you fall short of explaining clearly why flat-footedness has had so much undeserved bad press and why having an arch has long been thought advantageous.
Essentially, the height of one's arch is a poor and misleading method of determining if a person has a good or proper foot. Many people have low arch profiles and have feet that function very well, particularly in activities where high degrees of shock are delivered to the body through the foot.
The flat foot becomes a potential clinical problem when the term is used as a synonym for an excessively pronated foot. This is when a foot flattens or pronates longer in the walking cycle than it should. In the early part of the walking cycle, when the heel strikes the ground, it is desirable to pronate, or roll in, to help dampen shock. Later in the walking cycle, when the heel lifts off the ground, the foot should be stiff, not pronating, allowing stability for the transfer of weight to the other leg.
This prolonged pronation into the push-off phase of walking is rarely desirable or advantageous and, when present, can produce symptoms in the forefoot including bursitis, tendinitis, displacement of bones and arthritic changes.
Having excessive pronation is very different from being flat-footed. Individuals should be evaluated by a qualified professional to determine if they are excessively pronated or merely have a flat foot. When a patient is found to be excessively pronated, shoe inserts are often prescribed. These improve the timing mechanism of the foot to decrease excessive pronation and its related symptoms in the foot.
The conclusion you refer from a 1989 study of Army infantry trainees at Fort Benning, Ga., that "trainees with high arches suffered twice as many injuries, including sprains and stress fractures, as their flat-footed comrades," is a function of this same misunderstanding. The term high-arched foot is often used as a synonym for feet that do not pronate enough during the heel-strike phase of walking. This eliminates an important shock-dampening mechanism and leads to exactly the kind of symptoms that the high-arched trainees suffered from.
It would be unusual for flat feet, which absorb shock well, to suffer the same degree of shock-related injuries as the high-arched stiff foot does. The best foot type to have often depends on the activities that you ask it to perform. RUSSELL G. VOLPE Associate Prof., Orthopedic Sciences, N.Y. College of Podiatric Medicine Farmingdale, L.I., Dec. 3, 1990