A foot support insole is disclosed comprising an elongated, resilient, and semi-flexible body. The body has a size and a plan configuration which generally conform to the size and general shape of the foot of the user. The rearward portion of the body includes a relatively depressed heel cup. The heel cup is defined by a floor surrounded by a raised wall extending continuously around the lateral and rear sides of the floor. The wall is contoured to provide lateral and rear support for the foot heel.
The body also includes a metatarsal arch, or raised feature, located in its forward portion. The metatarsal arch has a relatively wide front section and a relatively narrow rear section. Between the metatarsal arch and the heel cup is a longitudinal medial arch, also providing a raised feature. The medial arch is more specifically located on an inner, medial portion of the body. Generally opposing the medial arch on the body is a longitudinal lateral arch. This raised feature is located on an outer, lateral portion of the body, extending from the raised wall of the heel cup forwardly past the rear section of the metatarsal arch.
As disclosed herein, this basic insole construction may be adapted to suit a wide variety of foot sizes and shapes. There are hundreds of different foot shapes among the human species and all include the same basic structural and operational features. However, the area of each foot that varies considerably from person to person is the medial arch, also called the dynamic arch. The medial arch flexes downward to transfer weight to a support surface. It also springs back up, to return forces to the lower limbs of the person, while walking. The principal characteristics of this arch are its elasticity and the considerable number of small joints between its component parts. When these factors are taken into account, especially for a person with a particularly high medial arch, it can be appreciated that adequate support of the medial arch is critical to foot comfort and well-being.
It is for this reason that the primary focus and design considerations for the present invention revolve around the medial arch. The foot support insole herein is preferably constructed in four different degrees of medial arch support. These four different degrees of support satisfy arch support requirements for the vast majority of feet, and eliminate the need for expensive custom orthopedic supports in most instances. By selecting the foot support insole having the proper degree of medial arch support for their feet, the user will enjoy maximum support with even distribution of body weight over the foot.
A lateral arch support is also provided. The lateral arch is longitudinal in configuration, and is located on the outer, lateral portion of the foot support insole, on the opposite side of the insole from the medial arch. The lateral arch is formed from an outer support wall, and has a standard degree of height which corresponds approximately to one-half the height of the medial arch. The length of the lateral arch also increases with increased shoe size for the support insole. The purposes of the lateral arch are to control supination (an outward turning of the foot) of the foot, to control unwanted foot motion or shifting within the shoe, and to provide equal lateral balance for the foot.
A metatarsal arch, having a section which is transverse to the longitudinal axis of the foot support insole, is also included. The raised extent of the metatarsal arch is somewhat circular or tear-drop shaped in configuration, providing support for the foot by distributing pressure more evenly on the forefoot and toes. The metatarsal arch has the characteristics of a "hemi-arch" or half dome which has a portion directed downwardly and rearwardly toward the medial arch. Thus, when the medial borders of the feet are placed in apposition to the foot metatarsal, a complete tarsal dome is formed. With the inclusion of this metatarsal arch in the foot support insole, body weight will be distributed more evenly over the metatarsal bones of the forefoot. It is a physiological fact that the metatarsal arch does not vary in degree from person to person as much as the medial arch. Thus, the foot support insole of the present invention employs a height for the metatarsal arch which varies only slightly, for varying degrees of medial arch and for varying shoe sizes for the insoles.
The heel portion of the foot is an extremely important part of the foot that is normally overlooked in most supportive insoles. Because the bottom of the foot heel resembles the curvature of a tennis ball, it is not difficult to visualize that an unsupported foot heel will tend to move and roll from side to side within a shoe. In addition, the bottom of the heel will have more of a high pressure, point contact with the shoe, since certain bottom and lateral portions are unsupported. Consequently, the foot support insole disclosed herein includes a weight-bearing deep heel cup. The heel cup includes a continuous wall, extending from one side, around the rear side, and ending on the opposite side. The wall includes a downwardly and inwardly inclined contoured portion extending to the floor of the cup. This contoured portion is configured to accommodate the curved portion of the heel snugly and comfortably.
The foot support insole is readily manufactured in standard shoe sizes. As will be discussed in more detail below, the primary variables for insoles of different shoe sizes are the length and the width of the insole, the length of the medial arch, and the length of the lateral arch.
A foot support insole of the proper size and providing the proper degree of medial arch support is inserted into the interior of any shoe or boot and adjusted to lie flat on the floor. Then, the user's foot is inserted into the shoe or boot, to lie over the support insole. Owing to the three raised features in the body, at the locations of the medial arch, the lateral arch, and the metatarsal arch, these foot arches are fully supported. The depressed heel cup supports the heel, and helps to restrain lateral and longitudinal movements of the foot. The weight of the user is thereby distributed more evenly across the user's foot bed and unwanted movement and rolling of the foot is inhibited.
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