Sole construction for energy storage and rebound

A sole construction for supporting at least a portion of a human foot and for providing energy storage and return is provided. The sole construction includes a generally horizontal layer of stretchable material, at least one chamber positioned adjacent a first side of the layer, and at least one actuator positioned adjacent a second side of the layer vertically aligned with a corresponding chamber. Each actuator has a footprint size smaller than that of the corresponding chamber, and is sized and arranged to provide individual support to the bones of the human foot. The support structure when compressed causes the actuator to push against the layer and move the layer at least partially into the corresponding chamber. In one embodiment, dual action energy storage and rebound is provided by using a plurality of actuators that move both upwardly and downwardly into corresponding chambers. In another embodiment, lateral stability is improved by using tapered actuators having a convex shape to accommodate the natural rolling movement of the foot.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to articles of footwear, and more particularly, to a sole construction that may be incorporated into athletic footwear or as an insert into existing footwear and the like in order to store kinetic energy generated by a person. The sole construction has a combination of structural features enabling enhanced storage, retrieval and guidance of wearer muscle energy that complement and augment performance of participants in recreational and sports activities.

2. Description of the Related Art

From the earliest times when humans began wearing coverings on their feet, there has been an ever present desire to make such coverings more useful and more comfortable. Accordingly, a plethora of different types of footwear has been developed in order to meet specialized needs of a particular activity in which the wearer intends to participate. Likewise, there have been many developments to enhance the comfort level of both general and specialized footwear.

The human foot is unique in the animal kingdom. It possesses inherent qualities and abilities far beyond other animals. We can move bi-pedially across the roughest terrain. We can balance on one foot, we can sense the smallest small grain of sand in our shoes. In fact, we have more nerve endings in our feet than our hands.

We literally roll forward, rearward, laterally and medially across the bony structures of the foot. The key word is “roll.” The muscles of the foot and ankle system provide a controlled acceleration of forces laterally to medially and vise-versa across the bony structure of the foot. In bio-mechanical terms these motions are referred to as pronation and supination. The foot is almost never applied flat, in relative position to the ground, yet shoe designers continue to anticipate this event.

The increasing popularity of athletic endeavors has been accompanied by an increasing number of shoe designs intended to meet the needs of the participants in the various sports. The proliferation of shoe designs has especially occurred for participants in athletic endeavors involving rigorous movements, such as walking, running, jumping and the like. In typical walking and running gaits, it is well understood that one foot contacts the support surface (such as the ground) in a “stance mode” while the other foot is moving through the air in a “swing mode.” Furthermore, in the stance mode, the respective foot “on the ground” travels through three successive basic phases: heel strike, mid stance and toe off. At faster running paces, the heel strike phase is usually omitted since the person tends to elevate onto his/her toes.

Typical shoe designs fail to adequately address the needs of the participant's foot and ankle system during each of these successive stages. Typical shoe designs cause the participant's foot and ankle system to lose a significant proportion, by some estimates at least thirty percent, of its functional abilities including its abilities to absorb shock, load musculature and tendon systems, and to propel the runner's body forward.

This is because the soles of current walking and running shoe designs fail to address individually the muscles and tendons of a participant's foot. The failure to individually address these foot components inhibits the flexibility of the foot and ankle system, interferes with the timing necessary to optimally load the foot and ankle system, and interrupts the smooth and continuous transfer of energy from the heel to the toes of the foot during the three successive basic phases of the “on the ground” foot travel.

Moreover, in vigorous athletic activities, the athlete generates kinetic energy from the motion of running, jumping, etc. Traditional shoe designs have served merely to dampen the shock from these activities thereby dissipating that energy. Rather than losing the kinetic energy produced by the athlete, it is useful to store and retrieve that energy thereby enhancing athletic performance. Traditional shoe construction, however, has failed to address this need.

Historically, manufacturers of modem running shoes added foam to cushion a wearer's foot. Then, gradually manufacturers developed other alternatives to foam-based footwear for the reason that foam becomes permanently compressed with repeated use and thus ceases to perform the cushioning function. One of the largest running shoe manufacturers, Nike, Inc. of Beaverton, Oreg., has utilized bags of compressed gas as the means to cushion the wearer's foot. A German manufacturer, Puma A G, has proposed a foamless shoe in which polyurethane elastomer is the cushioning material. Another running shoe manufacturer, Reebok International of Stoughton, Mass., recently introduced a running shoe which has two layers of air cushioning. Running shoe designers heretofore have sought to strike a compromise between providing enough cushioning to protect the wearer's heel but not so much that the wearer's foot will wobble and get out of sync with the working of the knee. The Reebok shoe uses air that moves to various parts of the sole at specific times. For example, when the outside of the runner's heel touches ground, it lands on a cushion of air. As the runner's weight bears down, that air is pushed to the inside of the heel, which keeps the foot from rolling inward too much while another air-filled layer is forcing air toward the forefoot. When the runner's weight is on the forefoot, the air travels back to the heel.

In the last several years, there have been some attempts to construct athletic shoes that provide some rebound thereby returning energy to the athlete. Various air bladder systems have been employed to provide a “bounce” during use. In addition, there have been numerous advancements and materials used to construct the sole and the shoe in an effort to make them more “springy.”

Furthermore, midsole and sole compression, historically speaking, can be very destabilizing. This is because pitching, tipping and lateral shear of the sole and midsole naturally rebound energies in the opposite direction required for control and energy transfers. Another perplexing problem for shoe engineers has been how to store energy as the foot and ankle system rolls laterally to medially. These rotational forces have been very difficult to absorb and control.

No past shoe designs, including the specific ones cited above, are believed to adequately address the aforementioned needs of the participant's foot and ankle system during walking and running activities in a manner that augments performance. The past approaches, being primarily concerned with cushioning the impact of the wearer's foot with the ground surface, fail to even recognize, let alone begin to address, the need to provide features in the shoe sole that will enhance the storage, retrieval and guidance of a wearer's muscle energy in a way that will complement and augment the wearer's performance during walking, running and jumping activities.

U.S. Pat. No. 5,595,003 to Snow discloses an athletic shoe with a force responsive sole. However, among the problems with the Snow embodiments is that they teach very thick soles comprised of tall cleats, a resilient membrane, deep apertures, and “guide plates.” The combination of these components is undesirable because they make up a very heavy shoe. Furthermore, Snow shows numerous small parts that would be cost prohibitive to manufacture. These numerous small cleats cannot affect enough rubber molecules through the resilient membrane to provide a competitive efficiency gain without increasing the thickness of the membrane to the point of impracticability. The heavier and taller midsole and sole of Snow also position the foot further from the ground, providing less stability as well as less neuro-muscular input. Moreover, it takes a longer period of time for Snow's cleats to “cycle,” i.e., penetrate and rebound. This produces a limiting effect for performance and efficiency gain potential.

Snow's cleats also require vertical guidance, i.e., anti-tipping, such as by Snow's required guide plate. Snow also fails to provide appropriate points of leverage for specific bone structures of the foot, control over the intrinsic rotational involvement of the foot and ankle system, bio-mechanical guidance, and the ability to produce tunable vertical vectors and transfer energy forward and rearward from heel, midfoot, forefoot and toes and vice-versa.

In my earlier invention disclosed in U.S. Pat. No. 5,647,145 issued Jul. 15, 1997, I teach an athletic footwear sole construction that enhances the performance of the shoe in several ways. First, the construction described in the '145 patent individually addresses the heel, toe, tarsal and metatarsal regions of the foot to allow more flexibility so that the various portions of the sole cooperate with respective portions of the foot. In addition, a resilient layer is provided in the sole which cooperates with cavities formed at various locations to help store energy.

While the advancements in shoe construction described above, including the '145 patent, have provided a great benefit to the athlete, there remains a continued need for increased performance of athletic footwear. There remains a need for an athletic footwear sole construction that can store an increased amount of kinetic energy and return that energy to the athlete to improve athlete performance.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and useful sole construction that may be incorporated into footwear or used as an insert into existing footwear.

It is another object of the present invention to provide a structure for use with footwear that stores kinetic energy when a compressive weight is placed thereon and which releases that energy when the weight is taken off.

It is a further object of the present invention to provide footwear and, specifically, a sole construction therefor, that enhances the performance of a person wearing the footwear.

The present invention provides an athletic footwear sole construction designed to satisfy the aforementioned needs. In one aspect of the present invention, the athletic footwear sole provides a combination of structural features under the heel, midfoot and forefoot regions of the wearer's foot that enable enhanced storage, retrieval and guidance of muscle energy in a manner that complements and augments wearer performance in sports and recreational activities. The sole construction of the present invention enables athletic footwear for walking, running and jumping to improve and enhance performance by complementing, augmenting and guiding the natural flexing actions of the muscles of the foot. The combination of structural features incorporated in the sole construction of the present invention provides unique control over and guidance of the energy of the wearer's foot as it travels through the three successive basic phases of heel strike, mid stance and toe off.

Accordingly, one aspect of the present invention is directed to an athletic footwear having an upper and sole with the sole having heel, midfoot, metatarsal, and toe regions wherein the sole comprises a foundation layer of stiff material attached to the upper and defining a plurality of stretch chambers, a stretch layer attached to the foundation layer and having portions of elastic stretchable material underlying the stretch chambers of the foundation layer, and a thrustor layer attached to the stretch layer and having portions of stiff material underlying and aligned with the stretch chambers of the foundation layer and with the portions of the stretch layer disposed between the thrustor layer and foundation layer. Given the above-defined arrangement, interactions occur between the foundation layer, stretch layer and thrustor layer in response to compressive forces applied thereto upon contact of the heel and midfoot regions and metatarsal and toe regions of the sole with a support surface so as to convert and temporarily store energy applied to heel and midfoot regions and metatarsal and toe regions of the sole by a wearer's foot into mechanical stretching of the portions of the stretch layer into the stretch chambers of the foundation layer. The stored energy is thereafter retrieved in the form of rebound of the stretched portions of the stretch layer and portions of the thrustor layer. Whereas components of the heel and midfoot regions of the sole provide temporary storage and retrieval of energy at central and peripheral sites underlying the heel and midfoot of the wearer's foot, components of the metatarsal and toe regions of the sole provide the temporary storage and retrieval of energy at independent sites underlying the individual metatarsals and toes of the wearer's foot.

In another aspect of the present invention, a sole is adapted for use with an article of footwear to be worn on the foot of a person while the person traverses along a support surface. This sole is operative to store and release energy resulting from compressive forces generated by the person's weight on the support surface. This sole is thus an improvement which can be incorporated with standard footwear uppers. Alternatively, the invention can be configured as an insert sole which can be inserted into an existing shoe or other article of footwear.

In one embodiment, the sole has a first layer of stretchable resilient material that has opposite first and second surfaces. A first profile is formed of a stiff material and is positioned on the first side of the resilient layer. The first profile includes a first profile chamber formed therein. This first profile chamber has an interior region opening toward the first surface of the resilient layer. The first profile and the resilient layer are positioned relative to one another so that the resilient layer spans across the first interior region. A second profile is also formed of a stiff material and is positioned on the second side of the resilient layer opposite the first profile. This second profile includes a primary actuator element that faces the second surface of the resilient layer to define a static state. The first and second profiles are positioned relative to one another with the primary actuator element being oriented relative to the first profile chamber such that the compressive force between the foot and the support surface will move the first and second profiles toward one another. When this occurs, the primary actuator element advances into the first profile chamber thereby stretching the resilient layer into the interior region defining an active state. In the active state, energy is stored by the resilient layer, and the resilient layer releases this energy to move the first and second profiles apart upon removal of the compressive force.

Preferably, the second profile has a second profile chamber formed therein. This second profile chamber has a second interior region opening toward the second surface of the resilient layer so that the resilient layer also spans across this second region. A plunger element is then provided and is disposed in the first interior region. This plunger element moves into and out of the second interior region when the first and second profiles move between the static and active states. Here, also, a plurality of plunger elements may be disposed in the first interior region with these plunger elements operative to move into and out of the second interior region when the first and second profiles move between the static and active states. The plunger element may be formed integrally with the first layer of resilient material.

A third profile may also be provided, with this third profile having a third profile chamber formed therein. This third profile chamber has a third interior region. Here, a second layer of stretchable resilient material spans across the third region. The first profile then includes a secondary actuator element positioned to move into the third interior region and to stretch the second layer of resilient material into the third profile chamber in response to the compressive force. The first profile may also include a plurality of second actuators, and these actuators may extend around a perimeter thereof to define the first profile chamber. The third profile then has a plurality of third chambers each including a second layer of resilient material that spans thereacross. These third profile chambers are each positioned to receive a respective one of the secondary actuators. The first profile in the second actuator may also be formed as an integral, one-piece construction. The third profile and the plunger element may also be formed as an integral, one-piece construction.

The sole according to the present invention can be a section selected from the group consisting of heel sections, metatarsal sections and toe sections. Preferably, the sole includes one of each of these sections so as to underlie the entire foot but to provide independent energy storing support for each of the three major sections of the foot. Alternatively, the present invention may be used in connection with only one or two sections of the foot. In any event, the invention allows either of the first or second profiles to operate in contact with the support surface.

The present invention also contemplates an article of footwear incorporating the sole, as described above, in combination with a footwear upper. In addition, the present invention contemplates an insert sole adapted for insertion into an article of footwear.

In another aspect of the present invention, a support structure provides energy storage and return to at least a portion of a human foot. This support structure comprises a generally horizontal layer of stretchable material, at least one chamber positioned adjacent a first side of the layer, and at least one actuator positioned adjacent a second side of the layer vertically aligned with a corresponding chamber. Each actuator has a footprint size smaller than that of the corresponding chamber. The support structure when compressed causes the actuator to push against the layer and move the layer at least partially into the corresponding chamber. Each actuator is selectively positioned to provide individual support to a portion of the human foot selected from the group consisting of a toe, a metatarsal bone, a midfoot portion and a heel portion.

In another embodiment, an energy storage and return system for footwear and the like is provided. The system comprises at least two stretchable layer portions, each of the portions having an upper side and a lower side. A plurality of actuator elements is provided, wherein at least one of the actuator elements is positioned above a stretchable layer portion and at least one of the actuator elements is positioned below a stretchable layer portion. A plurality of receiving chambers is also provided, wherein each receiving chamber corresponds to one of the actuator elements and is sized and positioned to receive at least partially the corresponding actuator element therein when the actuator elements are compressed toward the receiving chambers. Each of the receiving chambers is preferably located opposite a corresponding actuator element across a stretchable layer portion.

In another aspect of the present invention, an energy return system for footwear and the like is provided. This system comprises at least one layer of stretchable material having a first side and a second side. A plurality of chambers is positioned on either the first side or the second side of the layer. A plurality of actuators each vertically aligned with a corresponding chamber is positioned opposite the chambers across at least one layer of stretchable material, each actuator having a footprint size smaller than that of the chamber. When the footwear receives a generally vertical compressive force, the actuator pushes against the layer and moves at least partially into a chamber. The actuators are patterned according to the structure of the human foot.

In another aspect of the present invention, a sole construction for underlying at least a portion of a human foot is provided. This sole construction comprises a generally horizontal layer of stretchable material having a first side and a second side. A chamber layer having a chamber therein is positioned on the first side of the layer of stretchable material, the chamber having at least one opening facing the first side of the layer of stretchable material. An actuator is positioned on the second side of the layer of stretchable material, the actuator having a footprint size that is smaller than that of the opening of the chamber such that when the sole construction is compressed, the actuator presses against the second side of the layer of stretchable material and at least partially into the chamber of the chamber layer. The actuator is at least partially tapered, which, as used herein, refers to a dimensional reduction in the size of the actuator, either in a vertical or a horizontal direction. For instance, the tapering of the actuator can refer to a vertical decrease in thickness of the actuator, such as by giving the actuator a dome-like shape or sloping surfaces, or by reducing the height or other dimension of the actuator horizontally, such as by tapering or sloping the upper or lower surface of the actuator towards the front of the foot.

In another aspect of the present invention, a sole construction for supporting at least a portion of a human foot is provided. This sole construction comprises a generally horizontal layer of stretchable material having a first side and a second side. A profile piece having a primary chamber therein is positioned on the first side of the layer of stretchable material, the primary chamber having at least one opening facing the first side of the layer of stretchable material. A primary actuator is positioned on the second side of the layer of stretchable material, the primary actuator having a footprint size that is smaller than that of the opening of the primary chamber such that when the sole construction is compressed, the primary actuator presses against the second side of the layer of stretchable material and at least partially into the primary chamber of the first layer. A secondary chamber is positioned within the primary actuator, the secondary chamber having at least one opening facing the second side of the layer of stretchable material. A secondary actuator is positioned on the first side of the layer of stretchable material, the secondary actuator having a footprint size that is smaller than that of the opening of the secondary chamber such that when the sole construction is compressed, the secondary actuator presses against the first side of the layer of stretchable material and at least partially into the secondary chamber.

In another aspect of the present invention, a heel portion for a sole construction is provided. The heel portion comprises a main thrustor, a first layer of stretchable material positioned above the main thrustor, and a satellite thrustor layer positioned above the first layer of stretchable material. The satellite thrustor has an upper surface and a lower surface, the upper surface of the satellite thrustor layer preferably having a plurality of satellite thrusters extending upwardly therefrom. The satellite thrustor layer also has a central opening therein. The heel portion further comprises a second layer of stretchable material positioned above the satellite thrustor layer and a foundation layer positioned above the second layer of stretchable material. The foundation layer preferably has an upper surface and a lower surface and a plurality of satellite openings positioned to receive the satellite thrustors. The heel portion when compressed causes the main thrustor to stretch through the first layer of stretchable material at least partially into the central opening of the satellite thrustor layer and the satellite thrusters to stretch through the second layer of stretchable material at least partially into the satellite openings.

In another aspect of the present invention, a sole construction is provided comprising a generally horizontal layer of stretchable material, a plurality of chambers positioned adjacent a first side of the layer, and a plurality of interconnected actuator elements positioned adjacent a second side of the layer. Each actuator element is vertically aligned with a corresponding chamber and has a footprint size smaller than that of the corresponding chamber. The support structure when compressed causes the actuator element to push against the layer and move the layer at least partially into the corresponding chamber.

These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when considered in connection with the drawings which show and describe exemplary embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The description provided hereinbelow illustrates seven exemplary embodiments of a sole construction according to the present invention. It should be appreciated that each of these embodiments is merely exemplary. Therefore, features from one or more of the embodiments may be added or removed from other embodiments without departing from the scope of the invention. Furthermore, the energy storage and rebound characteristics as described in one embodiment may also be applicable to the other embodiments when similar mechanisms are involved. Moreover, as used herein, the terms “thrustor,” “plunger,” “lug” and “actuator” are substantially interchangeable and generally refer to actuators used for the storage and rebound of energy.

In general, the embodiments described below provide chambered actuators patterned according to the structure of the foot. In these embodiments, patterned rigidity ensures a smooth transfer of energies (the energy “wave”) across the foot. The chambers provide holes for the energy to flow into. Energy always follows the path of least resistance. The staggering of active support actuators and energy exchange chambers balances and supports the intrinsic rolling action of metatarsal bones, toes and heel.

The controlled storing and rebound of energy as described herein do not force the foot into undesired movement; rather it supplies superior position, force and speed information to allow supination and pronation controlling musculature to store and release energy from the energy “wave” process. This produces an efficiency gain, a “tightening up” of the foot's rotational passes through the neutral plane. The resulting sequential stability manages complex energy transfers and storing demands across the foot, enabling the predictable specific vertical vector rebound or thrust of energy required for measurable efficiency gains.

Multiple intrinsic rate limiting factors together control the speed at which the human neuro-muscular system acts and reacts within its natural environment. Rate limiting factors include the contractile proteins actin and myosin, the speed of neuro-muscular input and feedback systems, the natural dash pot effect of involved musculature, the genetic makeup, i.e., ratio of fast to slow twitch muscle fibers, the individual training environment, etc.

With this in mind, there is an optimum speed at which muscles will receive the most energy as well as force, position, perceived resistance and speed information from the environment. Chambered actuators provide a tunable environment for energy and environmental information to be provided to the neuro-muscular skeletal system. Tighter tolerances and shorter drops produce sprint speed efficiency gains, while looser tolerances and increased drops produce slower running speed efficiency gains.

Chambered actuators also resist tipping through the controlled stretching of the membrane externally and more importantly internally, balancing the stretch producing a lateral-to-medial cradling effect. As described below, chambered actuators can utilize either a rigid or rubber internal pattern lug offering optional compression of a rubber lug or the superior vertical guidance of a rigid, e.g., plastic, internal pattern lug.

Raised nesting patterns on the elastic layers provide additional specifically placed thickness while limiting additional weight. Chambered actuators produce a very small footprint in relationship to the amount of surface area, “stretch zone,” activated by impact or weight bearing. This generates more power, less weight, less required actuator penetration and faster cycle time.

With these general concepts in mind, the embodiments of the present invention are described below.

First Exemplary Embodiment

Referring to the drawings and particularly toFIGS. 1 and 2, there is illustrated a first exemplary embodiment of an article of athletic footwear for walking, running and/or jumping, being generally designated10. The footwear10includes an upper12and a sole14having heel and midfoot regions14A,14B and metatarsal and toe regions14C,14D wherein are provided the structural features of the sole14constituting the present invention. The sole14incorporating the construction of the present invention improves the walking, running and jumping performance of a wearer of the footwear10by providing a combination of structural features which complements and augments, rather than resists, the natural flexing actions of the muscles of the foot to more efficiently utilize the muscular energy of the wearer.

Referring toFIGS. 1 and 3to8, the heel and midfoot regions14A,14B of the sole14basically includes the stacked combination of a footbed layer16, an upper stretch layer18, an upper thrustor layer20, a lower stretch layer22, and a lower thrustor layer24. The footbed layer16of the sole14serves as a foundation for the rest of the stacked components of the heel and midfoot regions14A,14B. The footbed layer16includes a substantially flat foundation plate26of semi-rigid semi-flexible thin stiff material, such as fiberglass, whose thickness is chosen to predetermine the degree of flexion (or bending) it can undergo in response to the load that will be applied thereto.

The foundation plate26has a heel portion26A and a midfoot portion26B. The foundation plate26has a continuous interior lip26C encompassing a central opening28formed in the foundation plate26which provides its heel portion26A with a generally annular shape. The flat foundation plate26also has a plurality of continuous interior edges26D encompassing a corresponding plurality of elongated slots30formed in the foundation plate26arranged in spaced apart end-to-end fashion so as to provide a U-shaped pattern of the slots30starting from adjacent to a forward end26E of the foundation plate26and extending rearwardly therefrom and around the central opening28. The slots30are preferably slightly curved in shape and run along a periphery26F of the foundation plate26but are spaced inwardly from the periphery26F thereof and outwardly from the central opening28thereof so as to leave solid narrow borders respectively adjacent to the periphery26F and the central opening28of the foundation plate26. The slots30alone or in conjunction with recesses32of corresponding shape and position in the bottom of the shoe upper12define a corresponding plurality of peripheral stretch chambers34in the foundation plate26.

The upper stretch layer18is made of a suitable elastic material, such as rubber, and includes a flexible substantially flat stretchable body36and a plurality of compressible lugs38formed on and projecting downwardly from the bottom surface36A of the flat stretchable body36at the periphery36B thereof. The peripheral profile of the flat stretchable body36of the upper stretch layer18generally matches that of the flat foundation plate26of the footbed layer16. In the exemplary embodiment shown inFIGS. 1,3and5to8, the compressible lugs38are arranged in a plurality of pairs thereof, such as six in number, spaced apart along opposite lateral sides of the flat stretchable body36. Other arrangements of the compressible lugs38are possible so long as it adds stability to the sole14. For ease of manufacture, the compressible lugs38are preferably integrally attached to the flat stretchable body36.

The upper thrustor layer20disposed below and aligned with the upper stretch layer18includes a substantially flat support plate40preferably made of a relatively incompressible, semi-rigid semi-flexible thin stiff material, such as fiberglass, having a construction similar to that of the flat foundation plate26of the footbed layer16. The flat support plate40may have a heel portion40A and a midfoot portion40B. The support plate40also has a continuous interior rim40C surrounding a central hole42formed through the support plate40which provides its heel portion40A with a generally annular shape. The central hole42provides an entrance to a space formed between the flat stretchable body36of the upper stretch layer18and the flat support plate40spaced therebelow which space constitutes a main central stretch chamber44of said sole14. The peripheral profile of the upper thrustor layer20generally matches the peripheral profiles of the footbed layer16and upper stretch layer18so as to provide the sole14with a common profile when these components are in an operative stacked relationship with one on top of the other.

The upper thrustor layer20also includes a plurality of stretch-generating thrustor lugs46made of a relatively incompressible flexible material, such as plastics, and being mounted on the top surface40D of the flat support plate40and projecting upwardly therefrom so as to space the flat support plate40below the flat stretchable body36of the upper stretch layer18. The thrustor lugs46are arranged in a spaced apart end-to-end fashion which corresponds to that of the slots30in the foundation plate26so as to provide a U-shaped pattern of the thrustor lugs46starting from adjacent to a forward end40E of the flat support plate40and extending rearward therefrom and around the central opening42. The thrustor lugs46run along a periphery40F of the support plate40but are spaced inwardly therefrom and outwardly from the central opening42of the support plate40so as to leave solid narrow borders respectively adjacent to the periphery40F and the central opening42of the support plate40.

The peripherally-located thrustor lugs46thus correspond in shape and position to the peripherally-located slots30in the flat foundation plate26of the footbed layer16defining the peripherally-located stretch chambers34. For ease of manufacture the thrustor lugs46are attached to a common thin sheet which, in turn, is adhered to the top surface40D of the flat support plate40.

The flat support plate40of the upper thrustor layer20supports the thrustor lugs46in alignment with the slots30and thus with the peripheral stretch chambers34of the foundation plate26and upper12of the shoe10. However, the flat stretchable body36of upper stretch layer18is disposed between the stretch generating thrustor lugs46and flat foundation plate26. Thus, with the footbed layer16, upper stretch layer18and upper thrustor layer20disposed in the operative stacked relationship with one on top of the other in the heel and midfoot regions14A,14B of the sole14, spaced portions36C of the flat stretchable body36of the upper stretch layer18overlie top ends46A of the stretch-generating thrustor lugs46and underlie the peripheral stretch chambers34. Upon compression of the footbed layer16and upper thrustor layer20toward one another from a relaxed condition shown inFIGS. 5 and 6toward a loaded condition shown inFIGS. 7 and 8, as occurs upon impact of the heel and midfoot regions14A,14B of the sole14of the shoe10with a support surface, the spaced portions36A of the flat stretchable body36are forcibly stretched by the upwardly movement of the top ends46A of the thrustor lugs46upwardly past the interior edges26D of the foundation plate26surrounding the slots30and into the stretch chambers34. This can occur due to the fact that the thrustor lugs46are enough smaller in their footprint size than that of the slots30so as to enable their top ends46A together with the portions36A of the flat stretchable body36stretched over the top ends46A of the thrustor lugs46to move and penetrate upwardly through the slots30and into the peripheral stretch chambers34, as shown inFIGS. 7 and 8.

The compressible lugs38of the upper stretch layer18are located in alignment with the solid border extending along the periphery26F of the foundation plate26outside of the thrustor lugs46. The compressible lugs38project downwardly toward the support base40. The compressive force applied to the foundation plate26of the footbed layer16and to the support plate42of the upper thrustor layer20, which occurs during normal use of the footwear10, causes compression of the compressible lugs38from their normal tapered shape assumed in the relaxed condition of the sole14shown inFIGS. 5 and 6, into the bulged shape taken on in the loaded condition of the sole14shown inFIGS. 7 and 8. In addition to adding stability, the function of the compressible lugs38is to provide storage of the energy that was required to compress the lugs38and thereby to quicken and balance the resistance and rebound qualities of the sole14

As can best be seen inFIGS. 1 and 3, the stretch-generating thrustor lugs46are generally greater in height at the heel portion40A of the support plate40than at the midfoot portion40B thereof. This produces a wedge shape through the heel and midfoot regions14A,14B of the sole14from rear to front, that effectively generates and guides a forward and upward thrust for the user's foot as it moves through heel strike to midstance phases of the foot's “on the ground” travel.

Referring toFIGS. 2,3and8, the lower-stretch layer22is in the form of a flexible thin substantially flat stretchable sheet48of resilient elastic material, such as rubber, attached in any suitable manner, such as by gluing, to a bottom surface40G of the flat support plate40of the upper thruster layer20. The lower thrustor layer24disposed below the flat stretchable sheet48of the lower stretch layer22includes a thrustor plate50, a thrustor cap52and a retainer ring54. The thrustor plate50preferably is made of a suitable semi-rigid semi-flexible thin stiff material, such as fiberglass. The thrustor plate50is bonded to the bottom surface of a central portion48A of the stretchable sheet48in alignment with the central hole42in the support plate40of the upper thrustor layer20. In operative stacked relationship of the stretchable sheet48of the lower stretch layer22between the stretch-generating thrustor plate50of the lower thrustor layer24and the support plate40of the upper thrustor layer20, the periphery48B of the central portion48A of the stretchable sheet48overlies the peripheral edge50A of the stretch-generating thrustor plate50and underlie the rim40C of the support plate40.

Upon compression of the lower thrustor layer24toward the upper thrustor layer20from a relaxed condition shown inFIGS. 5 and 6toward a loaded condition shown inFIGS. 7 and 8, as occurs upon impact of the heel and midfoot regions14A,14B of the sole14of the shoe10with a support surface during normal activity, the periphery48B of the stretchable sheet48is forcibly stretched by the peripheral edge50A of the thrustor plate50upwardly past the rim40C surrounding the central hole42and into the main central stretch chamber44. This can occur due to the fact that the thrustor plate50is enough smaller in its footprint size than that of the central hole42in the support plate40so as to enable the thrustor plate50together with the periphery48B of the central portion48A of the stretchable sheet48stretched over the thrustor plate50to move and penetrate upwardly through the central hole42and into the main centrally-located stretch chamber44, as shown inFIGS. 7 and 8.

The rigidity of the thrustor plate50of the lower thrustor layer24encourages a stable uniform movement and penetration of the thrustor plate50and resultant stretching of the periphery48B of the central portion48A of the stretchable sheet48into the main central stretch chamber44in response to the application of compressive forces. The thrustor cap52is bonded on the bottom surface50A of the thrustor plate50and preferably is made of a flexible plastic or hard rubber and its thickness partially determines the depth of penetration and length of drive or rebound of the thrustor plate50. The ground engaging surface52A of the thrustor cap52is generally domed shape and presents a smaller footprint than that of the thrustor plate50. The retainer ring54is preferably made of the same material as the thrustor plate50and surrounds the thrustor plate50and thrustor cap52. The retainer ring54is bonded on the bottom surface of the stretchable sheet48in alignment with the central hole42in the support plate40and surrounds the thrustor plate50so as to increase the stretch resistance of the central portion48A of the stretchable sheet48and stabilize the lower thrustor layer24in the horizontal plane reducing the potential of jamming or binding of the thrustor plate50as it stretches the periphery48B of the central portion48A of the stretchable sheet48through the central hole42in the flat support plate40of the upper thrustor layer20.

The above-described centrally-located interactions in the heel and midfoot regions14A,14B of the sole14between the support plate40of the upper thrustor layer20, the flat stretchable sheet of the lower stretch layer22and flat thrustor plate of the lower thrustor layer24of the heel and midfoot regions14A,14B occur concurrently and interrelatedly with the peripherally-located interactions between footbed layer16, the flat stretchable body36of the upper stretch layer18and the thrustor lugs46of the upper thrustor layer20. These interrelated central and peripheral interactions convert the energy applied to the heel and midfoot regions14A,14B of the sole14by the wearer's foot into mechanical stretch. The applied energy is thus temporarily stored in the form of concurrent mechanical stretching of the central portion48A of the lower stretchable sheet48of the lower stretch layer22and of the spaced portions36C of the upper stretchable body36of the upper stretch layer18at the respective sites of the centrally-located and peripherally-located stretch chambers44,34. The stored applied energy is thereafter retrieved in the form of concurrent rebound of the stretched portions36C of the upper stretchable body36and the thrustor lugs46therewith and of the stretched portion48A of the lower stretchable sheet48and the thrustor plate40therewith. The resistance and speed of these stretching and rebound interactions is determined and controlled by the size relationship between the retainer ring54and the rim40C about the central hole42of the support plate49and between the top ends46A of the thrustor lugs46and the continuous interior edges26D encompassing the slots30of the foundation plate26. The thickness and elastic qualities preselected for the lower stretchable sheet48of the lower stretch layer22and the upper stretchable body36of the upper stretch layer18influence and mediate the resistance and speed of these interactions. The stretching and rebound of the lower stretchable sheet48also causes a torquing of the support plate40. The torquing can be controlled by the thickness of the support plate40as well as by the size and thickness of the retainer ring54.

Referring toFIG. 3, the midfoot region14B of the sole14of the present invention also includes a curved midfoot piece56and a compression midfoot piece58complementary to the curved midfoot piece56. The midfoot portion26B of the foundation plate26terminates at the forward end26E which has a generally V-shaped configuration. The curved midfoot piece56preferably is made of graphite and is provided as a component separate from the foundation plate26. The curved midfoot piece56has a configuration which is complementary to and fits with the forward end26E of the foundation plate26. The forward end26E of the foundation plate26cradles the number five metatarsal bone of the forefoot as the curved midfoot piece56couples the heel and forefoot portions14A,14B of the sole14so as to load the bones of the forefoot in an independent manner. The peripheral profiles of the upper stretch layer18and compression midfoot piece58are generally the same as those of the foundation plate26and curved midfoot piece56.

Referring now toFIGS. 1,2and9to11, the metatarsal and toe regions14C,14D of the sole14basically include the stacked combinations of metatarsal and toe articulated plates60A,60B, metatarsal and toe foundation plates62A,62B, a common metatarsal and toe stretch layer64, and metatarsal and toe thrustor layers65A,65B. The metatarsal and toe thrustor layers65A,65B include metatarsal and toe plates66A,66B, metatarsal and toe thrustor caps68A,68B and metatarsal and toe retainer rings70A,70B. Except for a common stretch layer64serving both metatarsal and toe regions14C,14D of the sole14, there is one stacked combination of components in the metatarsal region14C of the sole14that underlies the five metatarsals of the wearer's foot and another separate stacked combination of components in the toe region14D of the sole14that underlies the five toes of the wearer's foot. Except for the upper articulated plates60A,60B, the above-mentioned stacked combinations of components of the metatarsal and toe regions14C,14D of the sole14interact (stretching and rebound) generally similarly to the above-described interaction (stretching and rebound) of the stacked combination of components of the heel and midfoot regions14A,14B of the sole14. However, whereas the stacked combination of components of the heel and midfoot regions14A,14B provide interrelated main and peripheral sites for temporary storage and retrieval of the applied energy, the stacked combination of components of the metatarsal and toe regions14C,14D provide a plurality of relatively independent sites for temporary storage and retrieval of the applied energy at the individual metatarsals and toes of the wearer is foot. The additional components, namely, the articulated plates60A,60B, of the metatarsal and toe regions14C,14D each has a plurality of laterally spaced slits72A,72B formed therein extending from the forward edges74A,74B rearwardly to about midway between the forward edges74A,74B and rearward edges76A,76B of the articulated plates60A,60B. These pluralities of spaced slits72A,72B define independent deflectable or articulatable appendages78A,78B on the metatarsal and toe articulated plates60A,60B that correspond to the individual metatarsals and toes of the wearer's foot and overlie and augment the independent characteristic of the respective sites of temporary storage and retrieval of the applied energy at the individual metatarsals and toes of the wearer's foot.

More particularly, the metatarsal and toe articulated plates60A,60B are substantially flat and made of a suitable semi-rigid semi-flexible thin stiff material, such as graphite, while the metatarsal and toe foundation plates62A,62B disposed below the metatarsal and toe articulated plates60A,60B are substantially flat and made of a incompressible flexible material, such as plastic. Each of the metatarsal and toe foundation plates62A,62B has a continuous interior edge80A,80B defining a plurality of interconnected interior slots82A,82B which are matched to the metatarsals and toes of the wearer's foot. The continuous interior edges80A,80B are spaced inwardly from located inwardly from the peripheries84A,84B of the metatarsal and toe foundation plates62A,62B so as to leave continuous solid narrow borders86A,86B respectively adjacent to the peripheries84A,84B. The metatarsal and toe portions of the borders86A,86B encompassing or outlining the locations of the separate metatarsals and toes of the wearer's foot and of the appendages78A,78B on the articulated plates60A,60B are also separated by narrow slits88A,88B. The pluralities of interconnected interior slots82A,82B define corresponding pluralities of metatarsal and toe stretch chambers90A,90B in the respective metatarsal and toe foundation plates62A,62B.

The common metatarsal and toe stretch layer64is made of a suitable elastic stretchable material, such as rubber, and is disposed below the metatarsal and toe foundation plates62A,62B. The peripheral profile of the common stretch layer64generally matches the peripheral profiles of the articulated plates60A,60B and of the foundation plates62A,62B so as to provide the sole14with a common profile when these components are in an operative stacked relationship with one on top of the other. The common stretch layer64is attached at its upper surface64A to the respective continuous borders86A,96B of the foundation plates62A,62B between their respective continuous interior edges80A,80B and peripheries84A,84B.

The metatarsal and toe thrustor plates66A,66B are disposed below and aligned with the common stretch layer64and the pluralities of interconnected interior slots82A,82B in foundation plates62A,62B forming the metatarsal and toe stretch chambers90A,90B. The metatarsal and toe thrustor plates66A,66B are made of semi-rigid semi-flexible thin stiff material, such as fiberglass. The metatarsal and toe thrustor plates66A,66B are bonded to the lower surface64B of the common stretch layer64in alignment with the pluralities of interconnected interior slots82A,82B of forming the metatarsal and toe stretch chambers90A,90B of the foundation plates62A,62B. In the operative stacked relationship of the common stretch layer64between the stretch-generating metatarsal and toe thrustor plates66A,66B and the respective metatarsal and toe foundation plates62A,62B, portions92A,92B of the common stretch layer64overlie the peripheral edges94A,94B of the metatarsal and toe thrustor plates66A,66B and underlie the continuous interior edges80A,80B of the metatarsal and toe foundation plates62A,62B.

Upon compression of the lower metatarsal and toe thruster plates66A,66B toward the upper metatarsal and toe foundation plates62A,62B from a relaxed condition shown inFIG. 10toward a loaded condition shown inFIG. 11, as occurs upon impact of the metatarsal and toe regions14C,14D of the sole14of the shoe10with a support surface during normal activity, the portions92A,92B of the common stretch layer64are forcibly stretched by the peripheries94A,94B of the metatarsal and toe thrustor plates66A,66B upwardly past the continuous interior edges80A,80B of the metatarsal and toe foundation plates62A,62B into the metatarsal and toe stretch chambers90A,90B. This can occur due to the fact that the metatarsal and toe thrustor plates66A,66B are enough smaller in their respective footprint sizes than the sizes of the slots82A,82B in the metatarsal and toe foundation plates62A,62B so as to enable the metatarsal and toe thrustor plates66A,66B together with the portions92A,92B of the common stretch layer64stretched over the respective thrustor plates66A,66B to move and penetrate upwardly through the slots82A,82B and into the metatarsal and toe stretch chambers90A,90B, as shown in FIG.11.

The rigidity of the metatarsal and toe thrustor plates66A,66B encourages a stable uniform movement and penetration of the thrustor plates66A,66B and resultant stretching of the portions92A,92B of the common stretch layer64into the metatarsal and toe stretch chambers90A,90B in response to the application of compressive forces. The metatarsal and toe thrustor caps68A,68B are bonded respectively on the bottom surfaces96A,96B of the metatarsal and toe thrustor plates66A,66B and preferably is made of a flexible plastic or hard rubber and their respective thicknesses partially determine the depth of penetration and length of drive or rebound of the metatarsal and toe thrustor plates66A,66B. The metatarsal and toe retainer rings70A,70B are preferably made of the same material as the metatarsal and toe thrustor plates66A,66B and surround the respective thrustor plates66A,66B and thrustor caps68A,68B. The metatarsal and toe retainer rings70A,70B are bonded on the lower surface64B of the common stretch layer64in alignment with the interior slots82A,82B and surround the thrustor plates66A,66B so as to increase the stretch resistance of the portion92A,92B of the common stretch layer64and stabilize the metatarsal and toe thrustor plates66A,66B in the horizontal plane reducing the potential of jamming or binding of the thrustor plates66A,66B as they stretch the peripheries of the portions92a,92B of the common stretch layer64into the metatarsal and toe stretch chambers90A,90bin the metatarsal and toe foundation plates62A,62B.

The above-described plurality of stretching interactions between the metatarsal and toe foundation plates62A,62B, common stretch layer64and metatarsal and toe thrustor plates66A,66B of the metatarsal and toe regions14C,14D in their stacked relationship converts the energy applied to the metatarsals and toes by the wearer's foot into mechanical stretch. The applied energy is stored in the form of mechanical stretching of the metatarsal and toe portions92A,92B of the common stretch layer64at the respective sites of the metatarsal and toe stretch chambers90A,90B. The applied energy is retrieved in the form of rebound of the stretched portions92A,92B of the common stretch layer64and the thrustor plates66A,66btherewith. The resistance and speed of these stretching interactions is determined and controlled by the size relationship between the retainer rings70A,70B and the continuous interior edges80A,80B in the metatarsal and toe foundation plates62A,62B. The thickness and elastic qualities preselected for the common stretch layer64influence and mediate the resistance and speed of these interactions. The peripheral profiles of the metatarsal and toe thrustor plates66A,66B are generally the same. The previously described midfoot pieces56,58also provide a bridge between the components of the heel and midfoot regions14A,14B of the sole14and the components of the metatarsal and toe regions14C,14D of the sole14.

The metatarsal and toe regions14C and14D of the first preferred embodiment significantly improve the Snow tipping problem by employing metatarsal and toe thrustor layers with a single torsion armature. As shown inFIG. 9, the thrustor plates66A and66B and the thrustor caps68A and68B each preferably include an armature69extending between the lateral sides of the foot. This single torsion armature thereby interconnects the actuator elements of the plates66A,66B and caps68A,68B, to give the plates or caps the ability to conduct energy laterally to medially across the forefoot and toes across individual actuator elements corresponding to each of the bones of the toe or metatarsal region. This provides superior guidance and synergism between the actuator elements, as well as the opportunity to provide specific leverage points for the bony structure of the foot.

Further control over lateral to medial movement can be accomplished by increasing the height of the lateral and medial borders of the plates66A,66B and caps68A,68B. Raising the outer edges guides the foot's natural lateral to medial movement.

Preliminary experimental treadmill comparative testing of a skilled runner wearing prototype footwear10having soles14constructed in accordance with the present invention with the same runner wearing premium quality conventional footwear, has demonstrated a significantly improved performance of the runner while wearing the prototype footwear in terms of the runner's oxygen intake requirements. The prototype footwear10compared to the conventional footwear allowed the runner to use from ten to twenty percent less oxygen running at the same treadmill speed. The dramatically reduced oxygen intake requirement can only be attributed to an equally dramatic improvement of the energy efficiency that the runner experienced while wearing the footwear10having the heel construction of the present invention. It is reasonable to expect that this dramatic improvement in energy efficiency will translate into dramatic improvement in runner performance as should be reflected in elapsed times recorded in running competitions.

Second Exemplary Embodiment

In a second exemplary embodiment, the present invention is directed to articles of footwear incorporating a sole either as an integral part thereof or as an insert wherein the sole is constructed so as to absorb, store and release energy during active use. Thus, it should be appreciated that the invention includes such a sole, whether alone, as an insert for an existing article of footwear or incorporated as an improvement into an article of footwear. In any event, the sole is adapted to be worn on the foot of a person while traversing along a support surface and is operative to store and release energy resulting from compressive forces between the person and the support surface.

With reference first toFIGS. 12-14, the second exemplary embodiment of the present invention is shown to illustrate its most simple construction. As may be seen inFIG. 1, an article of footwear in the form of an athletic shoe110has an upper112and a sole114. Sole114includes a heel portion16that is constructed according to the second exemplary embodiment of the present invention.

The structure of heel portion116is best shown with reference toFIGS. 13,14A and14B. In these FIGS., it may be seen that heel portion16includes a first profile in the form of a heel piece118that is formed of a relatively stiff material such as rubber, polymer, plastic or similar material. Heel piece118includes a first profile chamber120centrally located therein with first profile chamber120being oval in configuration and centered about axis “A”. A second profile122is structured as a flat panel124that is provided with a primary actuator126that is similarly shaped but slightly smaller in dimension then first profile chamber120. Second profile piece122is also formed of a stiff material, such as rubber, polymer, plastic or similar material. Actuator126can be formed integrally with flat panel124or, alternatively, affixed centrally thereon in any convenient manner.

The first layer128of a stretchable resilient material is interposed between heel piece118and second profile piece122so that resilient layer128spans across first profile chamber120. To this end, it may be appreciated that heel piece118is positioned on a first side130of first resilient layer128while the second profile piece122is positioned on a second side132of first resilient layer128with actuator126facing the second side thereof. Moreover, it may be seen that first profile chamber120has a first interior region134that is sized to receive actuator126.

With reference toFIGS. 14A and 14B, it may be seen that heel piece118and second profile piece122are positioned so that a compressive force between the first and the support surface136in the direction of vector “F” moves heel piece118and second profile piece122toward one another. During this movement, the primary actuator element126advances into the first profile chamber120. As this happens, resilient layer128is stretched into the first interior region134to define the active state shown in FIG.14B. In the active state, energy is stored by the stretching of resilient layer128. However, when the compressive force is removed, resilient layer128operates to release the energy thereby to move heel piece118and second profile piece122apart from one another to return them to the static stage shown in FIG.14A. Accordingly, in operation, when a user places weight on the heel portion116, either from walking, running or jumping, the impact force is cushioned and absorbed by the stretching of resilient layer128. When the user transfers weight away from heel portion116, this energy is released thereby helping propel the user in his/her activity.

Third Exemplary Embodiment

The simple structure shown inFIGS. 12-14can be expanded to make a highly active sole, such as that shown in the third exemplary embodiment of theFIGS. 15-22. With reference toFIG. 15, it may be seen that an article of footwear in the form of an athletic shoe150has an upper152and a sole154with sole154being constructed according to the third exemplary embodiment of the present invention. Sole154includes a heel portion156, a metatarsal portion158and a toe portion160, all described below in greater detail. Thus, when reference is made to a “sole” it may be just one of these portions, a group of portions or a piece that underlies the entire foot or a portion thereof.

Turning first, then, to heel portion156, the structure of the same may best be shown with reference toFIGS. 17-19. In these figures, it may be seen that heel portion156includes a first profile162formed by an annular heel plate164that has a plurality of spaced apart auxiliary actuator elements166positioned around the perimeter. Actuator elements166are formed of a stiff, fairly rigid material and define a first profile chamber168which has an opening170formed in annular heel plate164. A layer of resilient stretchable material172is configured so that it will span across opening170with heel plate164and resilient layer172being secured together such as by an adhesive or other suitable means. Thus, first profile piece162is positioned on one side of resilient layer172, and a second profile piece174is positioned on a second side of resilient layer172and is affixed thereto in any convenient manner. Second profile piece174is in the form of a heel piece but defines a primary actuator element for interaction with chamber170. Thus, when used in this application, the phrase “second profile including a primary actuator element” can mean either that a second profile is provided with an independent actuator element or that the profile itself forms such actuator element.

In any event, it may further be appreciated that second profile piece174has a second profile chamber176formed centrally therein with second profile chamber176being an elongated six-lobed opening. Heel portion156then includes a third profile piece178that is provided with a plunger element180that is geometrically similar in shape to second profile chamber176but that is slightly smaller in dimension. Third profile piece178also includes a plurality of openings182that are sized and oriented to receive secondary actuator elements166noted above. To this end, also, heel portion156includes a second resilient layer184which has an elongated oval opening186centrally located therein. Openings182define third profile chambers each having a third interior region.

With reference now toFIGS. 18 and 19A, it may be understood that, when nested, the various pieces which make up heel portion156form a highly active system for storing energy. Here, it may be seen that plunger180of a selected height so that, when nested, surface188of plunger180contacts the second side190of resilient layer172. Simultaneously, upper surfaces192of secondary actuators166just contact surface194of second resilient layer184. Each of secondary actuator elements166align with a respective opening182with openings182having a similar shape as the configuration of actuator166but slightly larger in dimension. Second profile piece174is then aligned so that second profile chamber176is positioned to receive plunger180when second profile piece174moves into the interior region of first profile chamber168.

This movement, from the static state shown inFIG. 19Ais depicted in the active state of FIG.19B. Here it may be seen that resilient layer172is forced to undergo a dual stretching wherein first profile piece162, second profile piece174and plunger180counteract in a dual piston-like action. Resilient layer172is accordingly stretched both into first profile chamber168(by second profile piece174) and into the interior region of second profile chamber176(by plunger180).

At the same time, second resilient layer184undergoes a single deflection into each of the third profile chambers formed by openings182. It should now be appreciated that by making the third profile chambers small in vertical dimension, the undersurface153of upper152provides a limit stop so that peripheral support is attained by second actuator elements166while the primary energy storing occurs with the coaction of plunger180and second profile piece174on resilient layer172. To further assist in lateral stability, auxiliary positioning blocks196may be employed along with optional soft lugs198which extend downwardly between third profile piece178and second resilient layer184. Moreover, optional metatarsal support plates200may be employed if desired.

With reference again toFIG. 15, it may be seen that sole154is constructed so as to be oriented at a slight acute angle “a” relative to support surface “s” when in the static state, with heel portion156being elevated relative to toe portion160. Preferably angle “a” is in a range of about 2 degrees to 6 degrees. By providing this small angle, the release of the energy from the active state is not simply in the vertical direction during mid-stance to toe-off. Rather, since sole154pivots about the toe portion160, the restorative force therefore is angled slightly forwardly during this movement. This results in a component of the restorative force being transferred to propel the user in a forward direction.

With reference now toFIGS. 20 and 21, the construction of toe portion160may be seen in greater detail. Here, it may be seen that toe portion160is formed by a first profile piece208that includes a first profile by an upstanding perimeter wall212that extends around the peripheral edge of first profile piece208. As may be seen with reference toFIG. 20A, perimeter wall212is configured so that chamber210has five regions216-220, that correspond to each of the human toes. A first resilient layer222is shown in FIG.20B and has a peripheral edge that is geometrically congruent to first profile piece208. When assembled, first resilient layer222spans across first profile chamber210. The structure of toe portion160is completed with the addition of second profile piece224which is shown in FIG.20A. Second profile piece224is shaped geometrically similar to the interior side wall213of perimeter wall212so that it can nest in close-fitted, mated relation into first profile chamber210. Second profile piece224is provided with openings226-229that define second profile chambers which correspond to toe regions216-219. With reference again toFIG. 20A, it may be seen that each of these toe regions is provided with an upstanding plunger236-239which are sized for mated insertion into openings226-229, respectively.

Accordingly, as is shown inFIGS. 21A and 21B, toe portion160provides a dual acting energy storing system. When first profile piece208and second profile piece224are moved from the static state shown inFIG. 21Ato the active state shown inFIG. 21B, resilient layer222undergoes a double deflection. Second profile piece224, which defines the primary actuator, moves into first profile chamber210thus stretching resilient layer222into the interior region thereof. Simultaneously, each of the plungers236-239move into the corresponding opening226-229in second profile piece224thus stretching resilient layer222into the interior region of openings226-229.

For ease of manufacture, it is possible to provide plungers236-239as part of resilient layer222. Accordingly, this alternative structure is shown inFIG. 20Dwherein resilient layer222is shown to have plunger elements236′-239′ formed integrally therewith. InFIG. 20D, the opposite side of resilient layer of222′ is revealed from that shown in FIG.20B.

The structure of metatarsal portion158is similar to that of toe portion160. InFIGS. 22A-22C, it may be seen that metatarsal portion158is formed by a first profile piece218that includes a first profile chamber250formed therein. First profile chamber250is thus bounded by an upstanding perimeter wall252that extends around the peripheral edge of first profile piece208. As may be seen with reference toFIG. 20A, perimeter wall252is configured so that chamber250has five regions255-259, that correspond to each of the metatarsal bones. A first resilient layer262is shown in FIG.22B and has a peripheral edge that is geometrically congruent to first profile piece248. When assembled, first resilient layer262spans across first profile chamber250. The structure of metatarsal portion158is completed with the addition of second profile piece264which is shown in FIG.22C.

Second profile piece264is shaped geometrically similar to the interior side wall253of perimeter wall252so that it can nest in close-fitted, mated relation into first profile chamber250. Second profile piece264is provided with openings265-270that define second profile chambers. With reference again toFIG. 22A, it may be seen that first profile chamber250is provided with upstanding plungers275-280which are sized for mated insertion into openings265-270, respectively. Plungers275-280are oriented to extend between the metatarsal bones of the human foot.

Here again when first profile piece248and second profile piece264move from the static state to the active state, resilient layer262undergoes a double deflection. Second profile piece264which defines the primary actuator, moves into first profile chamber250thus stretching resilient layer262into the interior region thereof. Simultaneously, each of the plungers275-280move into the corresponding chambers265-270in second profile piece264thus stretching resilient layer262into the interior region of openings265-270. The action, therefore, is identical to that described with reference toFIGS. 21A and 21B.

The energy focal points for the toe profile piece224and the forefoot profile piece264center around the chambers226-229and265-270, respectively. These chambers are further stabilized by fore and aft torsion armatures which interconnect the actuator portions of actuators224and264and conduct energy laterally and medially across the forefoot and toe regions. As shown inFIG. 20C, a fore torsion armature230bounds the fore portion of the profile piece224, and an aft torsion armature232bounds the aft portion of the profile piece224. Similarly, as shown inFIG. 22C, a fore torsion armature272bounds the fore portion of the profile piece264, and an aft torsion armature274bounds the aft portion of the profile piece264.

Fourth Exemplary Embodiment

A fourth exemplary embodiment of the present invention is shown inFIGS. 23-27. In these FIGS. a sole insert310is shown to include an upper312and a sole314. Sole314includes a heel section316, a metatarsal318and a toe portion320. The structure of heel portion216is best shown inFIGS. 24 and 27Aand27B. Heel portion316includes a first profile piece322structured generally as flat plate323that has a plurality of first profile chambers324formed therein. Chambers324are formed as cavities in plate323. Alternatively, chambers324could be formed by openings completely through plate323. A second profile piece326includes a plurality of actuator elements328which are sized for engagement into the interior region of a respective chamber324. First profile piece324and second profile piece326sandwich a resilient layer330therebetween so that, when compression forces are exerted, actuator elements328are advanced into first profile chamber324.

Toe portion320is formed by a first profile piece344and a second profile piece346that defines an actuator. The structure of profile pieces344and346are identical to that described with respect to profile pieces208and224, respectively, so that this description is not repeated. Similarly, metatarsal portion318is formed by a first profile piece354and a second profile piece356with the structure of profile pieces354and356being the same as that of profile pieces348and364. One difference that may be noted in the structure of the sole insert310, however, is that the resilient layer330is a common resilient layer that extends along the complete sole of insert310so that resilient layer330provides the resilient layers for storing energy in each of heel portion316, metatarsal portion318and toe portion320.

Fifth Exemplary Embodiment

FIGS. 28-30illustrate a fifth exemplary embodiment of the sole of the present invention. This embodiment is similar to the third exemplary embodiment described above, with one difference being that the heel portion456does not have the optional soft lugs198shown inFIG. 17above. Toe portion460and metatarsal portion458, shown in a bottom view inFIG. 30, are substantially the same as shown in20A-20C and22A-22C, respectively, using like numerals in the 400 series rather than the 200 series.

FIGS. 28 and 29show the heel portion456in an exploded perspective view and an exploded partial cross-sectional view, respectively. The heel portion456includes a first profile462formed by an annular heel plate464that has a plurality of spaced apart auxiliary actuator elements466positioned around the perimeter in a U-shape. Actuator elements466are formed of a stiff, fairly rigid material and define a first profile chamber468which has an opening470formed in annular heel plate464. Actuator elements466are preferably tapered, as shown inFIG. 29, toward the front of the sole, to provide additional support toward the rear of the foot. A layer of resilient stretchable material472is configured so that it will span across opening470with heel plate464and resilient layer472being secured together such as by an adhesive or other suitable means. Thus, first profile piece462is positioned on one side of resilient layer472, and a second profile piece474is positioned on a second side of resilient layer472and is affixed thereto in any convenient manner. Second profile piece474is in the form of a heel piece but defines a primary actuator element for interaction with chamber470.

It may further be appreciated that second profile piece474has a second profile chamber476formed centrally therein with second profile chamber476being an elongated six-lobed opening. Heel portion456then includes a third profile piece478that is provided with a plunger element480that is geometrically similar in shape to second profile chamber476but that is slightly smaller in dimension. Third profile piece478also includes a plurality of openings482that are sized and oriented to receive secondary actuator elements466noted above. To this end, also, heel portion456includes a second resilient layer484which has an elongated oval opening486centrally located therein. Openings482define third profile chambers each having a third interior region.

To assist in lateral stability, auxiliary positioning blocks496are provided between the second resilient layer484and first profile piece464. Additional support blocks or motion control posts502are provided beneath the first profile piece substantially underlying the forward pair of secondary actuator elements466. The tripod configuration of the support blocks502and second profile piece474provides improved stability. The unit is capable of storing energies derived from rotational forces, producing optimal vertical vectors. Shoes requiring additional stability can take advantage of the ability to space the motion control posts further apart. For individuals having flat feet or requiring full support of the midfoot region, an optional active foot bridge is contemplated.

It should be understood that, when nested, the various pieces which make up heel portion456form a highly active system for storing energy. In particular, the heel portion456exhibits substantially similar behavior as the heel portion156depicted inFIGS. 19A and.19B.

The bottom view of the sole portion shown inFIG. 30depicts the arrangement of the heel portion456, metatarsal portion458and toe portion460comprising the exemplary sole of the shoe.FIG. 30also depicts an additional metatarsal support portion500, shown more particularly inFIGS. 31A-31C. As shown inFIG. 31A, the metatarsal support portion500is formed by a first profile piece504that includes a first profile chamber510defined by an upstanding perimeter wall512that extends around the peripheral edge of first profile piece504. A resilient layer506is shown in FIG.31B and has a peripheral edge that is geometrically congruent to first profile piece504. When assembled, resilient layer506spans across profile chamber510. The structure of metatarsal support portion500is completed with the addition of second profile piece508which is shown in FIG.31C. Second profile piece508is shaped geometrically similar to the interior side wall512of first profile piece504so that it can nest in close-fitted, mated relation into profile chamber510. More particularly, second profile piece508and chamber510are positioned to cradle the first and second metatarsal bones.

Sixth Exemplary Embodiment

FIGS. 32 and 33depict an alternative exemplary embodiment of a heel portion556for a sole of the present invention. The heel portion556comprises a main thrustor574, a first resilient layer572, a first profile layer562with actuator elements or satellite thrustors566thereon, interlocking rubber lugs598on a second resilient layer584, and a second profile layer578overlying the resilient layer584. Additionally auxiliary support blocks602are positioned proximal to the resilient layer572beneath the profile layer562.

The embodiment shown inFIG. 32is similar to the heel portion156shown inFIG. 17, with two differences being that the rubber lugs598are provided beneath the resilient layer584instead of the profile piece578, and that the embodiment inFIG. 32does not have a plunger similar to element180in FIG.17.

With reference toFIGS. 32 and 33, it may be seen that heel portion556includes a first profile562formed by an annular heel plate564that has a plurality of spaced apart auxiliary or satellite actuator elements566positioned around the perimeter in a U-shape. Actuator elements566are formed of a stiff, fairly rigid material and define a first profile chamber568which has an opening570formed in annular heel plate564. A layer of resilient stretchable material572is configured so that it will span across opening570with heel plate564and resilient layer572being secured together such as by an adhesive or other suitable means. Thus, first profile piece562is positioned on one side of resilient layer572, and a second profile piece574is positioned on a second side of resilient layer572and is affixed thereto in any convenient manner. Second profile piece574is in the form of a heel piece but defines a primary actuator element or main thrustor for interaction with chamber570. As shown inFIG. 33, second profile piece574preferably decreases or tapers in dimension in a downward direction, and more preferably has a substantially lower dome-like shape with sloping surfaces. This shape provides improved lateral support to the heel through three basic phases of foot movement of heel strike, mid stance and toe off.

Heel portion556includes a third profile piece or foundation layer578that includes a plurality of openings582that are sized and oriented to receive actuator elements566noted above. To this end, heel portion556includes a second resilient layer584. Openings582define second profile chambers each having a second interior region. The upper surfaces of actuators566just contact the lower surface of second resilient layer584. Each of secondary actuator elements566align with a respective opening582having a similar shape as the configuration of actuator566but slightly larger in dimension.

A pair of support blocks or motion control posts602are provided underlying the forward pair of actuators566. Like the second profile piece574, these posts602are preferably convex downward in shape, and are more preferably dome-like in shape and forwardly sloped to provide improved lateral stability to the sole.

The rubber lugs598are provided beneath the resilient layer584to substantially mate and interlock with the actuators566. Both the rubber lugs598and the actuators566are preferably tapered in a forward direction to allow for a more controlled lateral displacement during compression. The side walls of lugs598and566are preferably sloped approximately 3 to 6 degrees. Each of the lugs mirror each other to provide elastically cradled interaction. The space between the rubber lugs598and thrusters566is preferably less than about 0.020 inches, to keep particles larger than 0.020 out. Too tight of a seal creates a vacuum, slowing the rebound process. The interlock allows a sufficient air flow, particularly during rebound as a too-tight-of-a-seal creates a vacuum slowing the rebound process. In anticipation, this design leaves a large space between the motion control posts602to allow for the exit of air, water, etc.

The actuators566preferably have a raised nesting pattern to better interlock with the rubber lugs598. The nesting effect creates a more adaptable environment, improving the conversion of energies from rotational forces to vertical force storage and retrieval. By specifically increasing the thickness of the plate564near the actuators566, weight is also reduced. Nesting patterns also act as a relocator and stabilizer for actuators fostering the energy wave to vertical vectors. Nesting patterns increase the sensitivity of the main thrustor574maximizing the length of propulsion or drive of the rebounding thrustor. They also provide additional force at the end of the thrust cycle, and help keep actuators in place.

Varying the actuator rigidity increases the amount of control over the energy “wave” and the neuro-muscular system's sensitivity to it. If the user's foot naturally supinates, that action tends to put excessive motion control demands on the outer border of the forefoot, metatarsal number five. This excessive undesirable motion is sequentially captured by a chambered actuator, such as actuator574in the sixth exemplary embodiment described above, stored and released quickly enough that the negative motion itself becomes the energy for sending the foot laterally to medially enhancing neutral plane functioning. A more rigid chambered actuator resists tipping or diving to the outer lateral or medial borders, thereby stabilizing the interlocking energy storing process. Further details regarding varying the actuator rigidity is described in the seventh exemplary embodiment below.

Seventh Exemplary Embodiment

FIGS. 34-68illustrate a seventh exemplary embodiment of a sole construction according to the present invention. As used throughout this specification, the term “sole construction” refers to both a whole or a portion of the sole used to support a human foot. Furthermore, because the components described in the seventh exemplary embodiment are similar to many of the components described in the embodiments above, it should be appreciated that the terminology used to describe similar components in the above embodiments may be interchangeable with the terminology used below.

FIG. 34illustrates the preferred sole construction in an exploded perspective view, with each of the components shown upside-down. More particularly, the sole construction includes three regions, namely a heel portion700, a toe portion800, and a metatarsal or forefoot portion900. Heel portion700includes a main thrustor702, a first layer of resilient stretchable material704, a satellite thrustor layer706, a second layer of resilient stretchable material708and a foundation or secondary thrustor layer710. Toe portion800includes an actuator layer802and a chamber layer804. Forefoot or metatarsal portion900includes an actuator layer902and a chamber layer904. Each of the components comprising each portion of the foot is attached preferably using chemical bonding during a molding process as would be known to one skilled in the art. As described herein, the “top” of the sole construction as shown inFIGS. 34-68is designated as being toward the secondary thrustor layer710, and the “bottom” of the sole construction is designated as being toward the main thrustor702. Correspondingly, the heel portion700represents the back or rear of the sole construction and the toe portion800represents the front of the sole construction.

As shown inFIGS. 35-38, the main thrustor702is preferably tapered downward and has a substantially domed bottom surface712(shown toward the top ofFIG. 35) which slopes more in the forward direction, thereby providing lateral stability and allowing rotational movement to the heel bone of the human foot that it substantially directly underlies. The main thrustor702is substantially oval-shaped, as shown inFIG. 36, being longer in the front-to-rear direction than side-to-side. As shown inFIGS. 37 and 38, the main thrustor702includes an upstanding wall714, extending upwardly away from the bottom surface and defining a chamber716within the main thruster. This chamber716preferably has a six-lobed shape, similar to thrustor474in the fifth exemplary embodiment described above (see FIG.30), but is enclosed by bottom surface712. The wall714preferably slopes slightly outward as the wall extends away from the surface712. The main thrustor702is preferably designed to be slightly tapered toward the front of the foot, such that the height of the wall714at the rear end718of the thrustor is larger than the wall at the front end720of the thrustor. This design provides additional support to the rear of the heel while accommodating the rolling motion of the heel. In particular, the curved bottom surface712allows energy to spread out laterally when the sole construction is compressed and allows for more efficient movement as the sole construction crosses the ground.

In the illustrated embodiment, the thrustor702has a rear wall height of about 0.324 inches, which decreases to a height of about 0.252 inches at the front of the wall714. In this embodiment, the wall714is preferably sloped about 1.5 degrees. The bottom surface712connecting the walls and defining the bottom of the chamber716preferably has a thickness of about 0.125 inches. The height of the entire main thrustor702, from the top of the wall714to the bottommost point of the surface712is about 0.536 inches. As shown inFIG. 36, the length of the thrustor702, as measured along line37—37, is about 2.101 inches, and the width of the thrustor702, as measured along line38—38, is about 1.561 inches. It should be appreciated that these dimensions are merely exemplary of one embodiment, and numerous variations can be made to the dimensions of the sole construction. The preferred material for the thrustor702is a plastic such as Dupont HYTREL®, but other materials being more or less rigid may also be used. When greater rigidity is desired, for instance, fiberglass may be used.

FIGS. 39-41illustrate a first layer of resilient stretchable material704that is disposed above the main thrustor702of the sole construction shown in FIG.34. This layer is preferably made out of rubber, and has a substantially oval shape similar to but larger in footprint size than that of the main thrustor702. The layer704also includes a tongue722extending from the front of the layer704, and has corners724and726at the front of the layer704.

As shown inFIGS. 40 and 41, the top surface728of the layer704is preferably planar. The bottom surface730of the layer704preferably has a boundary region732which extends around the perimeter of the layer704in a substantially oval shape. Within this boundary region732is an intermediate region734also having a substantially oval shape, the intermediate region having a greater thickness than that of the boundary region. The increase in thickness between boundary region732and the intermediate region734is preferably gradual, thereby providing a sloped surface736as shown in FIG.41. Within the intermediate region734is a central stretch region738that is slightly recessed relative to the intermediate region734, and is separated from the intermediate region by a boundary ring740. This central stretch region738is sized to have substantially the same shape as the main thrustor702described above, such that when the sole construction is compressed during a walking or running activity, the thrustor702presses against the central region738causing it to stretch.

In the illustrated embodiment, the resilient layer704has a thickness of about 0.06 inches in the boundary region732, increasing to about 0.135 inches in the intermediate region734, and decreasing to about 0.125 inches in the central stretch region738. The length of the layer704, when measured from the front tip of the tongue722to the back of the layer704, is about 3.793 inches. The width of the layer704at its widest portion is about 2.742 inches. The length of the layer704, when measured from the corners724and726to the back of the layer704, is about 3.286 inches. When measured from the back of the layer to the frontmost edge of the intermediate region734, this length is about 3.098 inches. The width of the boundary region as it extends around the oval shape of the layer varies from about 0.298 inches at the rear of the layer to about 0.28 inches at the lateral sides of the layer. The slope of the surface736is preferably about 45°. Again, it should be appreciated that all of these dimensions are merely exemplary of one particular embodiment.

FIGS. 42-44illustrate the satellite thrustor layer706of the sole construction of FIG.34. As shown inFIGS. 42 and 43, the layer706comprises an annular heel plate742including an opening744which serves as a chamber through which main thrustor702and resilient layer704extend when the assembled sole construction is compressed. Thus, the opening or chamber744has a substantially oval shape which is large enough to contain the main thrustor702.

The preferred shape of the heel plate742is substantially annular, further comprising two extensions746and748toward the front of the foot. As shown inFIG. 34, the shape of the extensions746and748depends on whether the sole construction is for a right foot or a left foot. The design shown inFIG. 34is for a left foot, and accordingly, the left extension748preferably has a front surface752which is concave outward while the right extension746preferably has a front surface750which is convex outward. It will be appreciated, of course, that these shapes will be reversed for a sole construction for a right foot. Simply put, for either foot, the front surface of the inner extension is preferably convex outward and the front surface of the outer extension is preferably concave outward.

The top side of the layer706is preferably provided with a plurality of satellite thrustors754arranged substantially in a U-shape around the layer. As shown inFIG. 44, the top surfaces of these thrustors754are preferably tapered toward the front of the layer, as indicated by angle α. Furthermore, each satellite thrustor754preferably has a plurality of holes756extending partially therethrough. The holes756serve to reduce the weight of the satellite thrusters. In the preferred embodiment, two of the satellite thrusters are provided over the extensions746and748, while four thrustors are distributed around the opening744.

At the front of the layer706and extending from the underside of the extensions746and748are support blocks758and760which are preferably integrally formed with the layer706. As shown inFIG. 42, these support blocks preferably have substantially the same shape as the extensions746and748, in that the front surface of the inner support block758is preferably convex outward, while the front surface of the outer support block760is preferably concave outward. As shown inFIG. 44, these support blocks are preferably tapered toward the front of the layer706, as indicated by angle β, and have front and rear walls that are preferably sloped.

As shown inFIGS. 43 and 44, the satellite thrusters754and provided on the upper side of the layer706on a raised nesting pattern762. As shown inFIG. 44, the raised nesting pattern762creates chambers764between the satellite thrusters having a substantially trapezoidal shape as shown.

In the illustrated embodiment, the length of the layer706from the front surface750of extension746to the rear of the plate742is about 4.902 inches. The length of the oval-shaped opening744along its major axis is about 2.352 inches. The width of the layer706, as measured laterally across its widest portion, is about 2.753 inches. The width of the layer, as measured laterally across its narrowest portion, is about 1.776 inches. The satellite thrusters754are tapered, as shown inFIG. 44, about 1.58 degrees, as indicated by angle α. The support blocks758and760are preferably tapered about 3 degrees, as indicated by angle β, and have front and rear walls which are sloped about 7 degrees. The height of the layer706as measured from the underside of the plate742to the top of the tallest satellite thrustor, as indicated by plane B inFIG. 44, is about 0.477 inches. The plate742itself has a thickness of about 0.1 inches at its thinnest point. For the tallest thrustor, the holes756as measured from plane B preferably have a depth of about 0.427 inches. The height of the layer706, as measured from the bottom of the support block758, as indicated by plane C inFIG. 44to plane B, is about 0.726 inches. The layer706, including the satellite thrustors754, are preferably made of a material similar to the layer702, and in one preferred embodiment, is Dupont HYTREL®.

FIGS. 45-47illustrates the second layer708of resilient material. This layer is preferably made of rubber, and is shaped substantially to correspond with the shape of the satellite thrustor layer706. More particularly, like the layer706, layer708has a substantially annular shape with a substantially oval-shaped opening766therein and two extensions768and770protruding forward therefrom. The front surface of the outer extension770is preferably concave outward, while the front surface of the inner extension768is preferably convex outward.

Disposed around the opening760and on the extensions768and770are stretch regions772which correspond to the satellite thrustors754of layer706. These stretch regions772are preferably integrally formed with the layer708and have an increased thickness as shown inFIG. 47as compared to the rest of the layer708to give them a raised configuration. The stretch regions772are preferably substantially rectangular in shape having curved corners to correspond with the shape of the satellite thrusters. Each of these stretch regions772has a footprint size which is larger than that of the satellite thrustors754in order to allow the satellite thrustors to press through the stretch regions when the sole construction is compressed.

A plurality of compressible rubber lugs774and776is also provided around the layer708, preferably disposed between each of the stretch regions772. In the preferred embodiment, five lugs774are provided between the six satellite thrusters, with two additional lugs776provided at the front of layer708underlying extensions768and770. These rubber lugs774and776are preferably integrally formed with the layer708. More preferably, the lugs774and776are substantially rectangular in shape to conform to the shape of the stretch regions772. More particularly, the walls of the lugs774as between each of the stretch regions are preferably concave inward, as shown inFIG. 47, such that they mate with the shape of the stretch regions772. As shown inFIG. 47, the lugs preferably extend substantially downward away from the layer708, and have sloped walls. These lugs are therefore shaped to mate with the chambers764of the satellite thrustor layer706, and provide energy storage and return when the sole construction is compressed causing compression of the lugs774in the chambers764. The lugs776at the front of the layer708are shaped to correspond with the shape of the extensions768and770.

As shown inFIG. 46, for the illustrated embodiment the layer708has a length measured from the back of the layer708to the front surface of extension768of about 5.17 inches. The width of the layer at its widest portion is about 3.102 inches, and at its narrowest portion is about 2.236 inches. The width of the annular portion of layer708measured from the rear of the layer to the rear of the opening766is about 1.02 inches. The distance from the rear of the layer708to the front of the opening766is about 3.138 inches. The width of the opening as measured across its minor axis is about 1.302 inches. The layer708along its outer edge has a thickness of about 0.05 inches. At the raised stretch regions772the thickness is about 0.120 inches, and at the lugs774and776the thickness is about 0.319 inches. The lugs774are preferably sloped about 7 degrees to mate with the chambers764.

The foundation or secondary thrustor layer710is shown inFIGS. 48-51. The thrustor layer710comprises a plate778having a plurality of openings or chambers780therein. This plate778is shaped substantially the same as the resilient layer708and satellite thrustor layer706, in that it is substantially oval-shaped corresponding to the shape of the heel with two extensions782and784extending -from the front. The chambers780are arranged to correspond with the satellite thrustors754of layer706, which will move into the chambers780through resilient layer708when the sole construction is compressed. Accordingly, chambers780have substantially the same footprint shape as the satellite thrusters754, but are sized slightly larger to accommodate the thrustors754.

A secondary thrustor786is provided on the underside of the plate778substantially centered within the chambers780and extending downward therefrom. This secondary thrustor786is positioned such that when the sole construction is assembled, the thrustor786extends through the opening766in resilient layer708and the opening744in satellite thrustor layer706. More particularly, the thrustor786preferably has a six-lobe shape which corresponds with the six-lobe opening716of main thrustor702. Thus, when the sole construction is compressed, the secondary thrustor786presses against the stretch portion738of resilient layer704and into the opening716. As shown inFIGS. 49 and 51, the bottom surface788of secondary thrustor786preferably has a curved or substantially domed shape, and preferably also has a pair of holes790extending partially therethrough to reduce the weight of the secondary thrustor. The layer710of the illustrated embodiment shown inFIGS. 48-51preferably has a length measured from the rear of the plate778to the front of extension782of about 5.169 inches. The width of the layer710across its widest portion is preferably about 3.105 inches, and across its narrowest portion is about 2.239 inches. The width between the outer lateral sides of extensions782and784is preferably about 2.689 inches. The front pair of chambers780preferably each has a length of about 1.25 inches and a width of about 0.63 inches. The plate710preferably has a thickness of about 0.06 inches, and the secondary thrustor preferably has a height as measured from the top side of the plate of about 0.71 inches. The holes790in the secondary thrustor each has a diameter of about 0.35 inches and a depth of about 0.5 inches. The layer710is preferably made of a material such as Dupont HYTREL®, although other similar materials may also be used. For instance, when more rigidity is required, materials such as fiberglass and graphite may also be used.

FIGS. 52-55illustrate the toe actuator layer802of the sole construction of the seventh exemplary embodiment. This layer802is preferably made of rubber, with all of the elements described and shown inFIGS. 52-55being preferably integrally formed. The layer802preferably comprises a main resilient portion806. Provided on the lower side of the main portion806are the toe actuators808,810,812,814and816, corresponding to each of the human toes. As shown inFIG. 54, the toe actuators are preferably raised segments below the main portion806. The first through fourth toe actuators808-814also contain chambers818,820,822and824, respectively, within the actuators, which are substantially oval in shape. As shown inFIGS. 54 and 55, the toe actuator layer is preferably arched. Along the edges of the toe actuator layer802are upwardly-oriented walls826to contain the toe chamber layer804, described below.

The illustrated toe actuator layer802preferably measures about 4.165 inches from side-to-side. The toe actuator layer802preferably has a width measured from its frontmost point to its rearmost point of about 2.449 inches. The main portion806of the layer802preferably has a thickness of about 0.12 inches, with the actuators808-816having a height of about 0.12 inches measured from the underside of the main portion806. The walls826preferably extend about 0.16 inches away from the top side of the main portion806, and are preferably about 0.55 inches thick.

FIGS. 56-59illustrate the toe chamber layer804that corresponds with the toe actuator layer described above. The toe chamber layer804is also preferably made of Dupont HYTREL®, and is formed having an upstanding perimeter wall828that extends around the peripheral edge of the layer804to define a chamber830therein. The toe chamber layer804is shaped geometrically similar to the toe actuator layer and is also preferably arched as shown inFIGS. 58 and 59. As may be seen with reference toFIG. 57, perimeter wall828is configured so that chamber830has five regions832,834,836,838and840, that correspond to each of the human toes. Plungers842,844,846and848preferably having a substantially oval shape are provided in each of the first four regions832,834,836and838, respectively. The plungers are sized to be smaller than the corresponding chambers of layer802. Similarly, the actuators of the layer802press through the main portion806into the chamber830when compressed. Thus, the toe actuator layer and toe chamber layer together provide a dual action energy storage system. The energy storage and return characteristics of the toe portion800is substantially as described with respect toFIGS. 20A-20C, above.

In the illustrated embodiment, the perimeter wall828and the plungers842-848preferably have a height of about 0.16 inches. The layer804has a thickness of about 0.03 inches at its thinnest point within chamber830. The side-to-side length of the layer804is preferably about 4.044 inches and the front-to-rear width of the layer from its frontmost to rearmost point is about 2.326 inches.

The metatarsal or forefoot actuator layer902shown inFIGS. 60-64is designed similar to the toe actuator layer802. More particularly, the layer902is preferably made of rubber, with all of the elements described and shown inFIGS. 60-64being preferably integrally formed. The layer902preferably comprises a main resilient portion906. Provided below the main portion904are the metatarsal actuators908,910,912,914,916and918. As shown inFIG. 62, the metatarsal actuators are preferably raised segments below the main portion904. The metatarsal actuators each contain chambers920,922,924,926,928and930within the actuators, which are substantially oval in shape. As shown inFIGS. 62-64, the metatarsal actuator layer is preferably arched. Along the edges of the metatarsal actuator layer904are upwardly-oriented walls932to contain the metatarsal chamber layer904, described below.

The illustrated metatarsal actuator layer902preferably has a length of about 4.302 inches as measured across the side-to-side expanse of the metatarsals. The metatarsal actuator layer902preferably has a width of about 3.03 inches as measured from the frontmost to rearmost point of layer902. The main portion906of the layer902preferably has a thickness of about 0.12 inches, with the actuators908-918having a height of about 0.12 inches measured from the underside of the main portion906. The walls932preferably extend about 0.16 inches away from the top side of the main portion906, and are preferably about 0.55 inches thick.

FIGS. 65-68illustrate the metatarsal chamber layer904that corresponds with the metatarsal actuator layer902described above. The metatarsal chamber layer904is also preferably made of Dupont HYTREL®, and is formed having an upstanding perimeter wall934that extends around the peripheral edge of the layer904to define a chamber936therein. The metatarsal chamber layer is shaped geometrically similar to the metatarsal actuator layer and is also preferably arched as shown inFIGS. 67 and 68. As may be seen with reference toFIG. 66, perimeter wall934is configured so that chamber936has six regions938,940,942,944,946and948. Plungers950,952,954,956,958and960preferably having a substantially oval shape are provided in each of the regions938-948in the chamber936, respectively, which press downward through the main portion906of layer902into the chambers920-930when the sole construction is compressed. Accordingly, the plungers950-960are sized to be smaller than the corresponding chambers920-930of layer902. Similarly, the actuators908-918of the layer902press through the main portion906of layer902into the chamber936when compressed to provide dual action energy storage and return. This is substantially the same energy characteristic as described above with respect toFIGS. 22A-22C.

In the illustrated embodiment, the perimeter wall934and the plungers950-960preferably have a height of about 0.16 inches. The layer904has a thickness of about 0.03 inches at its thinnest point within chamber936. The length of the layer904is preferably about 4.182 inches, with a width of about 2.908 as measured between the frontmost and rearmost points of the layer904.

The sole construction of the embodiments described above is preferably attached to the underside of an upper of a shoe (not shown). The embodiments described above may further include an outersole or traction layer chemically bonded to the bottom of the sole construction for contact with the ground.FIGS. 69-76illustrate toe and forefoot traction layers designed for contact with the ground. As shown inFIGS. 69-73, the toe traction layer860is sized and shaped to conform substantially to the shape and size of the toe actuator layer802. Similarly, the forefoot traction layer960is sized and shaped to conform substantially to the shape and size of the forefoot actuator layer902. Each of these traction layers is preferably formed from a rubber material, and has lateral and medial borders that are approximately twice as tall as at its center to encourage foot and ankle rotation within the neutral plane. In one embodiment, the traction layers have a thickness of about 0.025 to 0.05 inches, with the thickness at the borders being about 0.05 inches and the thickness at the center being about 0.025 inches. It will be appreciated that traction layers may be also be provided underneath the heel portion, motion control posts and other portions of the sole construction. Furthermore, it is also contemplated that a single traction layer be provided underneath the entire sole construction.

As illustrated above, the actuators of the sole construction may have a varying rigidity to improve stability of the foot and to accommodate the foot's natural rolling motion. As illustrated by the seventh exemplary embodiment, this varying actuator rigidity may be provided by making the satellite thrustors754and secondary thruster786out of a more rigid material, such as 80 to 90 durometer Dupont HYTREL®, and making the main thrustor702out of a less rigid material, such as 40 to 50 durometer Dupont HYTREL®. Similarly, lugs774are preferably made of a less rigid material such as rubber. Thus, the sole construction has alternating rigidity which allows for fine tuning the energy storage and rebound provided by each of the actuators. Actuator rigidity may also be varied according to the desired use of the shoe. For instance, more compliant actuators may be desired to conform to uneven surfaces and for special use applications, such as trail running, golf and hiking. More rigid actuators may be used where greater performance is desired, such as for running and sprinting, vertical leaping, basketball, volleyball and tennis. It should therefore be appreciated that numerous possibilities exist for varying the rigidity of the actuators, in addition to varying their size, shape and position, to provide desired performance characteristics.

Furthermore, the curved shape of the actuators with corresponding curved chambers provides mechanical advantages to the performance of the sole construction. In particular, a curved actuator surface, when loaded, is pressured to a flatter state, causing an expansion of its footprint size into the stretchable layer. This expansion of the actuator increases the amount of stretching that the stretchable layer experiences, thereby leading to an increased storage and rebound of energy.

Experimental Results

The advantages of Applicant's invention are illustrated in the results of experimental tests performed on the shoe described in accordance with the seventh exemplary embodiment of the present invention (“Applicant's shoe”), as compared to a standard shoe. Unless otherwise noted, Mizuno Wave Runner Technology was used for the standard shoe. The results are presented below.

Whole body efficiency measures the consumption and expiration of gases. To determine the improvement of Applicant's shoe as compared to the standard shoe, graded and steady state exercise tests were performed to analyze the expired gases (determine VO2) with 3 or 12 lead electrocardiography during treadmill running on athletes. Specifically, VO2measures O2delivered by the heart/cardiac output.

Test subject athletes reported for testing on two occasions. On the first occasion each subject wore the standard shoe and VO2maxwas determined by a graded exercise test on a treadmill. On the second occasion the standard shoe and Applicant's shoe were compared using a 75-90% VO2maxgraded steady state intensity and absolute intensity protocol. The equipment used was a Sensor Medics Vmax29 metabolic cart equipped with two calibration gas tanks, one laptop computer with software installed, one printer, one VGA monitor and 12/3 lead EKG machines. Additionally, sets of flow sensors, tubing, mouthpieces and headgears, as well as an ample supply of EKG patch electrodes, were used.

In response to the same running protocol, Applicant's shoe demonstrated a reduced O2consumption at the same relative (80%-90%) VO2maxand absolute intensity in all male athletes tested. This finding was notable at intensities representing 80-90% VO2maxand at speeds of 9.5, 10, 10.5 and 11 miles/hr. This finding is consistent with an improved whole body efficiency when running in Applicant's shoe relative to the standard shoe at paces that are typical of those performed during racing and intense recreational training. The average improvement in whole body efficiency at the aforementioned intensities was 13%. However, at the higher absolute and relative intensities, the average improvement in whole body efficiency was 15%. Individual variability was present, as certain individuals demonstrated an average improvement of efficiency of 21% and 18%, respectively, at the same absolute intensity of 10, 10.5 and 11 miles/hr. This individual variation may be credited to initial differences in biomechanics, body mechanics or running style. Interestingly, the least improvement was measured in the ultradistance runners, whereas the greatest effect of the shoe was measured in shorter distance triathletes/duathletes. This finding is consistent with the idea that the ultradistance runners demonstrated improved mechanical or biomechanical efficiency initially when compared with the shorter distance cross-trained athlete. The overall findings were that every subject received whole body efficiency improvements using Applicant's shoe. Results varied between subjects due to biomechanics, body mechanics and running style. In conclusion, Applicant's shoe leads to improved running efficiency as demonstrated by the physiological data of all male athletes tested.

The preliminary data to compare whole body efficiency during like protocol treadmill running using Applicant's shoe and the standard shoe in a female elite athlete is consistent with data previously collected on men. Although the magnitude of the effect was less, the measured VO2was consistently lower at all measured workloads and the discrepancy between males and one female runner may be credited to different running mechanics (specifically, forefoot running in the female). To this effect, when mechanics were made more similar by an imposed grade during very fast treadmill running, the whole body efficiency was improved. It is likely that the improved whole body efficiency measured in an elite female athlete when wearing the experimental is similar to that measured previously in men.

As seen in male runners, in response to the same running protocol, Applicant's shoe demonstrated a reduced O2consumption at the same relative (80-90%) VO2maxand absolute intensity in an elite female runner. This finding was notable at intensities representing (80-95%) VO2maxand at speeds of 8.5, 9, 9.5 and 10 mph. This finding is consistent with an improved whole body efficiency when running in the experimental shoe relative to the standard shoe at paces that are typical of those performed during racing and intense recreational training. Although the magnitude of the improvement measured at different intensities was smaller than that measured in men, it is still a notable (around 3%) difference. To this difference, it was noted that the elite female athlete landed primarily on her forefoot. Hence, the total effectiveness of the shoe may not have been fully measured due to the construction of the shoe which places the major mechanism in the heel of the shoe. Of interest was the VO2measurement during exercise on the treadmill in response to a change in grade. Mechanically for a forefoot runner this grade change at a 10.5 mph speed may force the athlete to spring off from her heel and thereby explain the improvement in whole body efficiency measured. Specifically, we measured a 5-7% decrease in whole body efficiency in the light of an increase in workload. Therefore, this improvement in whole body efficiency in response to grade is greatly underestimated. On the other hand, this preliminary data offers insight as to more areas of investigation for the possibility of improved whole body efficiency due to the mechanics of the experimental shoe.

2. Whole Body Kinematic Test

Applicant has also performed a whole body kinematic test to show how the whole body receives benefits from Applicant's invention in particular, by providing more proper angles at the ankle, knee and hip and less vertical body movements.

A running stride analysis was performed on the two subjects to determine running temporal and kinematic parameters across varying shoes. The shoes tested were as follows: a regular pair of running shoes, and two pairs of running shoes designed to return energy to the runner (“Applicant's shoe”). The concept behind Applicant's shoe is that it absorbs the energy of impact with the ground and is able to transfer that energy back to the runner in the latter phases of stance, thus improving running economy. It was hypothesized that there would be observable changes in the running kinematics, notably, decreased stance time combined with an increased swing time (time in the air) as well as increased leg extension in late stance as the shoe returned energy.

Data was collected on one male (Subject 1) and one female (Subject 2). Eighteen joint markers were placed bilaterally on the following landmarks: the lateral aspect of the head of the 5thmetatarsal, the lateral malleolus, lateral approximation of the axis of rotation of the knee, lateral approximation of the axis of rotation of the hip, iliac crests, lateral approximation of the shoulder axis of rotation, lateral elbow, wrist, forehead and chin. Subject 1 was filmed with 3 video cameras at a frame rate of 30 frames per second while running on a treadmill at 10.0 mph (4.47 m/s). The trial order was: regular shoes, energy return shoes, lightweight energy return shoes. Subject 2 was filmed while running at 8.6 mph (3.84 m/s) and 10.0 mph (4.47 m/s). The video data was analyzed using the Ariel Performance Analysis System (APAS) to generate a three-dimensional image of the subject for each of the three trials. Trial information is provided below:

The temporal measure of the running stride were determined to be as follows:

The general sagittal plane-kinematic variables of stride length, vertical displacement and R foot travel are shown below. Stride length was determined from the stride rate determined above and the treadmill velocity, which was assumed to remain constant. The vertical displacement is the measure of the sagittal plane travel of the forehead marker. The travel of the right foot is the measure of the foot's sagittal displacement through one complete stance and swing cycle.

TABLE 2General Kinematic MeasurementsStrideVerticalR Foot travelSpeedTrialLengthDisplacementduring oneSubject(m/s)Number(m)(cm)running stride (m)14.4712.806.01.9514.4722.835.82.0114.4732.775.01.9423.8412.566.91.9124.4722.895.82.0023.8432.486.41.8624.4742.865.82.01
The lower extremity sagittal plane kinematics were determined for the right side. This included the hip, knee and ankle angles. Hip angle was calculated as the angle between the thigh and the pelvis and an increasing angle equals hip extension. Knee angle was calculated as the angle between the thigh and the shank segments and an increasing angle equals extension. Ankle angle was calculated as the angle between the shank and the foot and an increasing angle equals plantarflexion.

The maximum hip extension was observed just prior to toe off and maximum hip flexion was observed just prior to heel strike.

TABLE 3Hip KinematicsMaximumMaximumRange ofSpeedTrialhip extensionhip flexionmotion of theSubject(m/s)Number(degrees)(degrees)hip (degrees)14.471171.2130.440.814.472166.8128.238.614.473171.2131.040.223.841157.2108.548.724.472151.096.254.823.843157.0113.643.424.474158.2108.949.3
Knee angles indicated a yielding phase of knee flexion during the beginning of stance followed by knee extension through toe-off. During swing the knee rapidly flexed and then extended prior to heel strike. Range of motion of the yielding phase and the extension phase of stance are shown below, as is the maximum knee flexion observed during swing.

Ankle angle ranges of motion are shown in Table 5. The ankle plantarflexed during the initial phase of stance. Ankle dorsiflexion was observed through mid-stance and then plantarflexion from late stance through the initial phase of swing.

This study attempted to quantify kinematic and temporal changes in running mechanics at two speeds with two subjects across different types of footwear. General observations from this study can be made.

There were few changes in the temporal measures of stride rate, stance and swing times. Subject 1 had a slightly shorter stride rate in the third trial, meaning turnover had increased. The lack of differences may in part be due to the frame rate used in this study. The frame rate of 30 frames per second is inadequate to determine the precise moments of foot strike and toe off. This study did not use a mechanical foot switch to determine heel strike more accurately.

Subject 1 had a lower vertical displacement during trial 3 compared to trials 1 and 2. This could be an indication of better running economy. A lower vertical displacement may indicate less energy being expended to raise the body's center of mass, which could result in lower physiological costs.

There was an interesting difference in the kinematic parameters of the knee and ankle when comparing the trials 1 and 2 with trial 3 of Subject 1. There was a relatively higher degree of knee flexion during the yield phase of stance followed by a greater degree of knee extension. This could indicate that energy is being stored during the yield phase of trial 3 and returned to the lower extremity during the push off phase. The energy transfer might be observed as a greater knee extension during push off. The ankle kinematics followed a similar pattern. The range of motion of the ankle was greater in trial 3 than in the other two trials. These differences were not noted in Subject 2 across the same speeds.

It is interesting to note that the “original” energy return shoe showed few differences from the regular running shoe of trial 1. The patterns described above should be examined with a more complete study to determine if the shoe in trial 3 is significantly different than the other shoes.

Two F-Scan Tests were performed to show how Applicant's shoe tends to spread out high pressure areas of the feet from the ground up. Applicant's shoe was tested against Mizuno Wave Rider Technology, which claims to have 22% more shock absorbency than any current midsole technology.

Applicant's invention had a profound ability to spread out high-pressure areas of the foot from the ground up. A close comparison can be drawn to the effect an orthotic gives to the foot. Orthotics correct negative foot movements from the ground up to stabilize the foot in a neutral position instead of over-pronation or over-supination. In the forefoot, or ball of the foot, each metatarsal head gets a more equal share of the load placed upon it. As the biomechanics place heavy loads on certain metatarsals, the load will get shared by the others. The F-scan tests particularly demonstrated the equal loading of the metatarsals, significantly less amount of heel pressure when wearing Applicant's shoe.

4. Shock Absorption Tests

Shock absorption tests were performed on Applicant's shoe and the standard shoe. The shock absorption test uses a heel impact test machine constructed by ARTECH, featuring a one-inch diameter steel rod guided by a pair of linear ball bearings. The rod weighs eight pounds and a three pound weight is clamped to the rod to give a total weight of eleven pounds. A five hundred pound load cell placed under the specimen measures force produced during impact. Force and displacement are recorded by a computer using a 12-bit data acquisition system, for 256 milliseconds at millisecond intervals.

The ARTECH system uses a load cell under the specimen rather than an accelerometer on the drop shaft. G-force is calculated by subtracting the weight of the drop shaft and the spring force from the peak load force, which may offer a more direct measure of comfort.

The computer software calculates peak load and g-force as indicated above, and calculates energy return by comparing the height of the first rebound to the drop height at full compression.

The test data is the average of 10 drops for each style of footwear. In general, lower loads and shock (g value) suggest more comfort to the wearer. High-energy returns, while not as critical for comfort, may provide an appealing “spring” in the step, may reduce energy expenditure, and may indicate a resistance to packing down of the cushion material.

To provide a general comparison to the attached test results, a very comfortable athletic shoe produced a g value of 5.4, which included the rubber sole, EVA midsole and sockliner. A very uncomfortable athletic shoe had a g value of 8.7 and a men's loafer 16.2 fees.

The test procedure was slightly modified while testing these shoes. The submitted shoes were tested with the normal eleven pond weight and then with an added weight to total twenty-two pound weight. The shoes were also tested on a flat surface and at a 30° angle.

The test results are shown in the table below.

Three general phenomenon are observed with Applicant's invention:1. VERTICAL ENERGY RETURN—the shoe vertically returns or rebounds from where the user started.2. GUIDANCE—the shoe actually moves vertically without the side-to-side movement.3. CUSHIONING UPON IMPACT—the shoe continues to move for a longer duration than conventional athletic footwear, creating greater shock absorption.

When the shoe strikes the ground while running, the user decelerates and loses energy. Then, energy is needed to lift the foot and leg up against gravity to start the next stride. Because Applicant's invention returns a quantifiable amount of energy to assist in lifting the foot, heel and lower leg, less work (energy) is needed to run, and less oxygen is required to perform. This energy return can be defined as an “unweighing” of an individual.

A device was utilized that could hold any brand of athletic shoe, impacting the wall vertically and measuring recorded data from the length of rebound off the wall, the distance each shoe returned from the wall (measurements taken at 12″ and 18″) and weighted (117 lbs) giving us the energy return data used in the testing. Shoes used: Nike Air Tailwind, Nike Air Triax, Asics Gel Kayano, Asics Gel 2030, Brooks Beast, Saucony Grid Hurricane and Applicant's shoe. Applicant's shoe returned up to 22% more energy than current athletic shoe offerings.

Two different methods of testing vertical leap may be performed to compare vertical leaping ability of Applicant's shoe with current athletic footwear.

For the first test, at the University of Colorado Boulder campus, the athletic department training room uses a vertical leap-measuring device called a VERTECK. This device is commonly found in university, college and selected high school athletic training centers. The VERTECK is a free-standing, movable, vertically adjustable pole-like device with colored plastic strips representing various measurements.

First, a standing vertical reach is established. Standing flat-footed, with one or both arms extended vertically and stretching the fingertips, the subject tries to move the plastic strips out of the way. The mark where the strips are moved—or height—represents that subject's vertical reach. This height also represents the starting point for measurement vertically.

The subject then warms up by stretching, running, bounding and jumping. Tests may be performed by a minimum of 2 subjects each sequence.

The first subject stands directly under the VERTECK device, crouches down, then leaps vertically, knocking away the plastic strips. The measurement between standing vertical reach (or zero) and the highest plastic strip to move is the vertical leap measurement. The test may then proceed as follows.Round 1: Subject 1 uses Fila footwear—2 attempts (jumps) would be measured.Subject 2 uses Applicant's shoe—2 attempts would be measured.Round 2: Subject 1 uses Applicant's shoe.Subject 2 uses Fila footwear.Continue the Rounds by the subjects until exhausted.Record and compare all Rounds and attempts by each subject.

A comparative test has not yet been conducted using a prototype of Applicant's invention and the VERTECK device. If the VERTECK device is not available, a second measuring protocol may be used. As in method 1, vertical reach may be established by chalking the middle finger-tip of the subject and standing flat-footed, sideways to a vertical wall or 45 degree angle to a vertical wall, or facing the wall.

Reaching vertically, the top of the chalk mark is determined to be the vertical reach. By re-chalking the finger-tip with each vertical leap attempt, and measuring the distance from the vertical reach to the top of the finger-tip chalk mark, the vertical leap is determined. For this test, Applicant recorded subjects, number of attempts and scores with each leap. An average of 10% vertical leap improvement was exhibited using Applicant's shoe versus the Fila shoe in multiple attempts.

It should be appreciated that various elements from the different embodiments described herein may be incorporated into other embodiments without departing from the scope of the invention. It should also be understood that certain variations and modifications will suggest themselves to one of ordinary skill in the art. In particular, any dimensions given are purely exemplary and should not be construed to limit the present invention to any particular size or shape. The scope of the present invention is not to be limited by the illustrations or the foregoing description thereof, but rather solely by the appended claims.