Patent ID: 6915598

Claim:
An insole for insertion into footwear, comprising: (a) a first layer including: a heel portion of a first thickness, a forefoot portion, a mid portion connecting together said forefoot portion and said heel portion, said mid portion having a second thickness which is lees than the first thickness of the heel portion, and having an upward curvature, an upper surface extending along said forefoot portion, mid portion and heel portion and on which a person stands, said upper surface having said curvature at said mid portion, and a lower surface extending along said forefoot portion, mid portion and heel portion, said lower surface including a shallow recess in said mid portion, and said lower surface having said curvature at said mid portion, said first layer being made of a material having a first hardness; and (b) a flexible and resilient thin arch spring insert of a substantially constant thickness secured in said recess and following the curvature of the mid portion, said arch spring insert comprising a material having a second hardness which is greater than said first hardness; wherein the arch spring insert has a stiffness in a range between about 5 and 60 pounds/inch that permits flexion and elongation of the mid portion am an arch of a foot flattens during a stride.