WO2010059716A2

WO2010059716A2 - Footwear with impact absorbing system

Info

Publication number: WO2010059716A2
Application number: PCT/US2009/064977
Authority: WO
Inventors: Robert B. Weaver
Original assignee: Weaver Robert B
Priority date: 2008-11-18
Filing date: 2009-11-18
Publication date: 2010-05-27
Also published as: WO2010059716A3

Abstract

An article of footwear includes an upper portion forming a shell, a sole, and a spring extending between the upper portion and the sole. The spring suspends the heel portion of the shell above the rearward portion of the sole and extends around the shell above the heel portion and further extends around the sole at the rearward portion of the sole. The spring has nesting spring portions at each of the medial and lateral sides of the article of footwear, which form hinges forward of the heel portion and the rearward portion at the lateral and medial sides of the article of footwear.

Description

FOOTWEAR WITH IMPACT ABSORBING SYSTEM TECHNICAL FIELD AND BACKGROUND OF THE INVENTION

The present invention generally relates to footwear and, more particularly, to footwear that provides increased stability, cushioning, and optionally comfort, and, further, optionally enhances the energy return to the wearer of the footwear.

When running, a runner's foot transitions through three phases of contact with each stride. Initially, a runner's foot typically lands on its heel. As a result, the heel experiences a significant impact or shock, which is absorbed by the heel bone (calcaneum). Because this is a dynamic force, the impact on the heel can be multiples of the runner's body weight. Furthermore, this impact is transmitted up toward the runner's leg joints.

The second phase initiates when the runner's body weight shifts forward. When the runner's body weight shifts forward, the force shifts away from the heel towards the middle portion of the foot. In addition, the arch of the foot spreads out, with the sole taking up the entire weight of the body. Then the foot rolls toward the metatarsals, which creates a torsional twisting effect due to asymmetrical nature of the foot, including the varying lengths of the toes. This may cause the foot to tilt toward to the inside (medial portion) of the foot or to the outside (lateral portion) of the foot placing additional strains on the joints and ligaments. As the foot continues to roll forward and the runner's weight is transferred to the forefoot and the metatarsal bones, the force exerted is actually increased to and in some cases several multiples of the runner's body weight. This stress is distributed across the whole width of the forefoot by the muscles, ligaments, and tendons across the metatarsals. In an attempt to reduce the impact forces on knees and ankle joints, current shoe designs incorporate a wide variety of means to cushion the foot. For example, some athletic shoes include air pockets that are incorporated into the sole of the shoe/ However, some researchers believe that some cushioning can actually increase the impact forces. Others believe that not only can cushioning actually lead to an increase in the impact on the wearer's joints but it may also put the wearer at greater risk for injury due to the greater instability of the ankle joint.

Consequently, there is a need to provide footwear that reduces the risk of injury to the wearer, especially to the wearer's ankle, and in a manner that can enhance the wearer's performance, whether that performance is an athletic activity, such as running, playing basketball, playing tennis, hiking, playing racket ball, or a non-athletic activity, such as standing, for example at work, or during therapeutic exercises, such as walking, or may be used as an orthotic, or the like. SUMMARY OF THE INVENTION

Accordingly, the present invention provides footwear that reduces stress on the joints of the wearer and may enhance the wearer's performance.

In one form of the invention, an article of footwear includes an upper portion forming a shell, which has a heel portion and a toe region, a sole, with a rearward portion and a forward portion, and a spring. The spring extends between the upper portion and the sole and suspends the heel portion above the rearward portion of the sole. The spring extends around at least a portion of the shell above the heel portion and extends around at least a portion of the sole at the rearward portion. In addition, the spring includes nesting spring portions at each of the medial and lateral sides of the article of footwear, which form flexible bending arms at each of the medial and lateral sides of the article of footwear. For example, the nesting spring portions maybe forward of the heel portion and of the rearward portion of the sole.

In one aspect, the bending arms are spaced apart to form an inner bending arm and an outer bending arm, which form a gap there between at each side of the spring. In another aspect, the spring includes three nesting spring portions at each of the medial and lateral sides of the article of footwear, which are optionally spaced apart to form two gaps or openings at each side of the spring.

In other aspects, the spring includes a generally U-shaped upper portion and a generally U-shaped lower portion, with the upper portion of the spring wrapping around the shell above the heel portion, and the lower portion of the spring wrapping around the sole at the rearward portion. Further, the cross-section of the upper portion may increasing from its rearward end adjacent the rearward-most portion of the shell to its forward end adjacent the bending arms, hi further aspects, each of the upper portion of the spring and the lower portion of the spring includes a proximal end, which is forked or multifurcated. The multifurcated proximal ends of the upper portion are joined with the multifurcated ends of the lower portion to thereby form the nesting spring portions.

In yet other aspects, the article of footwear may optionally include a compressible body positioned between the heel portion of the shell and the rearward portion of the sole.

In further aspects, the compressible body may include one or more wedge-shaped recesses wherein the compressible body initially folds about the wedge-shaped recess and closes the wedge-shaped recess when a user applies a load to the heel portion of the shell. For example, the compressible body may have an accordion shape body. hi one embodiment, the compressible body comprises a compressible bladder, such as an air chamber. Further, the bladder may have a valve, including an adjustable valve, to adjust the pressure in the bladder. In another embodiment, the compressible body may comprise a gel body. Further, the compressible body may comprise a compressible bladder with a compressible core that is formed from a compressible material, such as foam or a gel, or another compressible bladder.

According to yet another form of the invention, an article of footwear includes an upper portion, which forms a shell, a sole, with a rearward portion spaced below the heel portion of the shell, and a spring, which suspends the heel portion of the shell above the rearward portion of the sole. In addition, the article of footwear includes a compressible body position between the heel portion and the rearward portion, which has a wedge-shaped recess. When a user initially applies a force at the heel portion, the compressible body folds about the wedge-shaped recess, which generates a first resistance over a first range of motion. When the compressible body is folded about the wedge-shaped recess and the wedge-shaped recess is substantially closed, and a user continues to apply a force at the heel portion, the compressible body generates a second resistance greater than the first resistance due to both the shortening of the moment arm of the spring and the increased resistance of the additional compression and deformation of the compressible body. In one aspect, the compressible body comprises at least one bladder.

In yet other aspects, the spring includes a generally U-shaped upper portion and a generally U-shaped lower portion, with the upper and lower portions being joined at their respective proximal ends forward of the rearward portion of the sole to form flexible, spring arms at lateral and medial sides of the footwear. hi a further aspect, each of the proximal ends of the upper and lower portions of the spring are multifurcated and form nesting spring portions. hi yet another form of the invention, an article of footwear includes an upper portion, which forms a shell, a sole, and at least two nested spring arms mounted at each of the medial and lateral sides of the footwear. Each of the spring arms form flexible bending portions at the medial and lateral sides of the footwear. For example, the bending arms may be forward of the rearward portion of sole and forward of the heel portion of the shell.

In one aspect, the spring arms comprise three generally C-shaped nested spring amis, with the C-shaped arms being forward or rearward facing.

In a further aspect, the spring amis at the lateral side are joined with the spring arms at the medial side.

According to yet further aspects, the article of footwear may also include a compressible member, such as a compressible bladder, positioned between the heel portion of the shell and the rearward portion of the sole.

An article of footwear according to yet another form of the invention includes an upper portion, which forms a shell, a sole, and a spring, which is configured to provide a first resistance over a first initial range of motion or angular rotation when a compressive force is applied to the spring body and a second resistance greater than the first resistance over a second range of motion or angular rotation after the first range of motion. The spring is mounted to the upper portion and the sole and includes generally reverse C-shaped or C-shapcd inner and outer flexible bending arms at the respective medial and lateral sides of the article of footwear that are spaced apart when unloaded. When loaded, the outer flexible bending arms pull closer to the inner bending arms to thereby reduce the strain in the outer flexible bending arms.

In one aspect, the rearward portion of the sole may have a curved sole portion to form a rocker member.

According to yet another form, a piece of footwear of the present invention may incorporate an air movement system that moves air through the footwear to cool the foot of the wearer of the footwear.

In one form of the invention, an article of footwear includes a sole having a heel portion, an upper portion forming a shell for enclosing at least a portion of the user's foot therein, and a fluid movement system. The fluid movement system includes a reservoir and a compressible bladder located beneath the heel portion of the upper portion wherein the bladder deforms from an uncompressed state to a compressed state under the application of a load at the heel portion of the upper portion. The fluid movement system further includes a valve between the reservoir and the bladder, which permits fluid flow from the reservoir to the bladder when the pressure in the reservoir is greater than the pressure in the bladder. The bladder has a discharge valve directing fluid into the upper portion or sole upon the application of the load thereby reducing the pressure in the bladder, and the fluid movement system further including a biasing member to generally at least partially return the bladder to its uncompressed state upon the removal of at least a portion of the load wherein a pressure lower than the pressure in the reservoir is generated in the bladder causing the inlet valve to open and permit fluid to enter into the bladder from the reservoir. hi one aspect, the biasing member is located in the bladder.

According to another aspect, the footwear further includes at least one passageway in the sole and/or the upper portion, which is in fluid communication with the exhaust valve and distributes the fluid exhausted by the bladder into the upper portion or sole. For example, the footwear may include a plurality of passageways for distributing fluid through the upper portion or the sole.

In yet another aspect, the article of footwear further includes a heating or cooling device to heat or cool the fluid in the fluid movement system.

According to other aspects, the reservoir may be located in the upper portion or the sole or may be external to the footwear and may comprise the air surrounding the footwear. In another form of the invention, an article of footwear includes a sole, an upper portion, and a fluid movement system, with the fluid movement system including a self-inflating bladder. A relief valve is in communication with the bladder to release fluid from the bladder into the sole and/or the upper portion when pressure in the bladder exceeds a predetermined pressure. Also provide is an intake valve, which allows fluid to enter the bladder when the pressure in the bladder is less than the pressure external of the footwear.

According to another form of the invention, an article of footwear includes a sole, an upper portion for at least partially enclosing a foot of a wearer of the footwear; and a heating/cooling system, which includes a heat sink for drawing heat from a user's foot located in the footwear, and which is being adapted to exhaust heat external to the footwear.

Li yet another form of the invention, an article of footwear includes a sole, an upper portion for partially enclosing a user's foot, and a cooling system for cooling a user's foot located in the footwear.

Accordingly, the present invention provides an article of footwear that can improve the comfort of a user of the footwear by improving the air flow through the footwear and optionally by providing enhanced heating or cooling features.

Accordingly, it can be appreciated that the footwear of the present invention is particularly suitable for use as athletic footwear, though not limited to athletic footwear.

Further, the energy storage member or members facilitate an enhanced performance on behalf of the wearer and, further, provide a reduced risk of injury to the wearer's foot by providing lateral stability while offering varying degrees of cushioning and energy return.

These and other objects, advantages, purposes, and features of the invention will become more apparent from the study of the following description taken in conjunction with the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is a rear perspective view of the footwear of the present invention; FIG. 2 is a side view of the footwear of FIG. 1; FIG. 3 A is a bottom perspective view of the footwear of FIG. 1 ;

FIG. 3B is a second bottom perspective view of the footwear of FIG. 1 ; FIG. 3C is a bottom plan view of the footwear of FIG. 1; FIG. 3D is a rear elevation view of the footwear of FIG. 1;

FIG. 4 is a side elevation of the footwear illustrating another embodiment of the air chamber;

FIG. 5 is a perspective view of one of a spring of the energy storage system of FIGS . 1 - 4;

FIG. 5 A is a perspective view of the spring of FIG. 5 shown molded as a unit with the heel cup; FIG. 6 is a perspective view of another embodiment of the spring of the present invention;

FIG. 7 is a side view of the spring of FIG. 6; FIG. 8 is a top plan view of the spring of FIG. 7;

FIG. 9 is a bottom plan view of the spring of FIG. 7;

FIG. 10 is a rear elevation view of the spring of FIG. 7;

FIG. 11 is a side elevation view of another embodiment of the spring of the present invention;

FIG. 12 is a side elevation view of another embodiment of the spring of the present invention;

FIG. 12A is a similar view of FIG. 12 illustrating the spring in compression;

FIG. 12B is a similar drawing to FIG. 12 but in color with a color scale showing the . . FIG. 13 is a perspective view of another embodiment of the footwear of the present invention incorporating an air movement system with an air chamber and air flow passages;

FIG. 14 is a second perspective view of the footwear of FIG. 13;

FIG. 15 is a schematic drawing illustrating the flow of heating and cooling fluid through the footwear; FIG. 16 is a perspective view of another embodiment of the bladder in FIG. 13;

FIG. 16A is a similar view to FIG. 16 showing the flow of fluid into and through the bladder;

FIG. 16B is a partial cross-section through the bladder of FIG. 16 illustrating the flow of air through the bladder; FlG. 16C is a cross-section of the bladder of FIG. 16;

FIG. 17A and 17B are cross-section pan views of the bladder of FIG. 16 illustrating a flow control device; and

FIG. 18A and 18B are plan cross-section views of the bladder of FIG. 16 illustrating another embodiment of the flow control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, the numeral 10 generally designates a shoe or article of footwear of the present invention. In the illustrated embodiment, footwear 10 comprises an athletic piece of footwear; however, it should be understood that various aspect of the footwear of the present invention may be incorporated into other types of footwear, including therapeutic footwear, everyday use footwear, industrial use or military use footwear, or just everyday use footwear. As will be more fully described below, athletic footwear 10 incorporates an energy storage system 12 that provides cushioning and reduces ground impact forces and, further, may improve the performance of the wearer of the footwear.

Referring again to FIG. 1, energy storage system 12 provides a spring system 14 that may be configured to reduce the overturning moment forces on the user's ankle to thereby reduce the risk of injury to the wearer by diverting the initial ground reactions forces to a region above the bottom of the heel and, optionally, at or near to ankle joint. This provides lateral stabilization, with the vertical forces directed down to the bottom of the heel; therefore, spring system 14 effectively separates vertical and lateral forces and decouples shoe stability from cushioning and/or energy storage and return,

Footwear 10 includes a sole 16 and an upper portion 18, which forms a shell for at least partially enclosing the foot of the wearer. Sole 16 is formed from a flexible impact absorbing material, such as rubber. As noted above, upper portion 18 forms a shell, which may be sculptured and shaped in order to most accurately conform to the user's foot shape. Suitable shells are made from light weight conventional materials or textiles, such as fabrics, leather, suede, or a combination of one or more of the above. Upper portion 18 may include cushioning material, such as neoprene foam or open celled foam, which may be positioned to evenly distribute forces from the foot to the shell. hi the illustrated embodiment, upper portion 18 forms a low-rise athletic footwear and includes a heel region 20, which extends below the heel of a wearer and further may extend upwardly to surround or semi-encompass the ankle joint of the wearer. Optionally, heel region 20 may extend as high or as above the ankle joint, but without interfering with the naturally dorsi or flexion movements of the ankle joint. With that configuration, heel region 20 may be held firmly against the talus bone by lacing or by a strap (not shown). It should be understood, therefore, that upper portion 18 may comprise a high-top type of shoe and further may include an opening at the ankle joint around the end of the fibula to avoid creating a pressure point at that point of the fibula. As described in U.S. Patent Nos. 6,557,271 and 6,964,119, which are herein incorporated by reference in their entirety, the energy storage system may be configured to provide the ability to directly transfer the lateral forces from the sole to a region above the bottom of the heel and, optionally, at or near the centroid of the ankle, with the ground reaction forces by passing the calcaneus bone and related connective tissues, thus avoiding a potential overturning moment and potential ankle joint sprain.

Referring to FIG. 2, in the illustrated embodiment, spring system 14 is formed from a monolithic spring 22 that includes an upper U-shaped spring portion 24 and a lower U-shaped spring portion 26, which are both arranged to extend at least partially around the rearward end of the shoe. Upper U-shaped portion 24 at least partially extends around and is secured to the heel portion 28 of the shell. Lower portion 26 at least partially extends around heel or rear portion 30 of sole 16. Though described as a monolithic spring, it should be understood that spring 22 may be formed from several springs (e.g. similar to leaf spring arrangements with vertically stacked springs) that are grouped or stacked together to generally form the U-shaped configuration with upper and lower spring portions or may be formed from discrete spring portions that are not joined at their rearward portion, more fully described below.

Spring portions 24 and 26 are sufficiently rigid, as described in the above-referenced co- pending application, to transfer reaction forces at the sole to a point above the bottom of the heel and, optionally, to a point at or near the user's ankle, such as at or near the centroid of the ankle joint. Further, spring portions 24 and 26 are joined at their respective proximal ends to form flexible, bending amis 32 on the lateral and medial sides of footwear 10 but which are sufficiently rigid (or at least in combination with the optimal compressible member described below) to suspend the heel portion 28 of the shell above the rear portion 30 of sole 16.

The result is an increased stability created by both spring portions 24 and 26, which provide both a vertical resistance force and a lateral resistance force and supply lateral forces back towards the ankle joint, which are antagonistic to one another. Furthermore, spring portions 24, 26 may create counteracting lateral forces that serve to provide support in the lateral directions. By connecting upper portion 24 to upper portion 18, spring portion 24 transfers the initial edge forces that occur at sole 16 to upper portion 18 — for example, where the connection point is aligned with the ankle joint, the forces are transferred directly to the height of the ankle joint. By transferring the reaction forces above the bottom of the heel, the energy storage system effectively transfers forces bypassing the calcaneus bone and related corrective tissues. Optionally, the reaction forces are transferred up to the height of the ankle joint centroid; thus, footwear 10 effectively eliminates the instability of the ankle joint by allowing the lateral forces to "bypass" the bottom of the foot heel and be directly transferred into the bottom of the Tibia and Fibula bones.

In addition, by connecting spring portion 24 at or near upper portion 18 and spring portion 26 at rearward portion or heel portion 30 of sole 16, spring portions 24 and 26 will accommodate large amounts of vertical movement through the cushioning process and, further, will provide support throughout the entire cushioning range. Furthermore, this allows the upper portion of the footwear to re-orient the vertical forces back down to the bottom of the user's heel, while leaving the lateral forces transferred to the user at a distance above the user's heel; thus, decoupling the vertical and lateral forces prior to transferring the forces to the user's foot.

Though illustrated as comprising external components, it should be understood that spring portions 24 and 26 may be embedded into the shell 18 of footwear 10, such as by injection molding, so as to integrate the structural components with the finished exterior surface of footwear 10 or may be enclosed by a flexible membrane. As noted, in the illustrated embodiment, spring portions 24 and 26 are formed by a single unitary spring, which may be pre-stressed when mounted in or to upper portion 18. Spring 22 may be formed from a plastic, such as nylon, including reinforced nylon, for example, 610 nylon, or from a metal, as well as fiber, such as carbon fiber, reinforced composites. Alternately, spring portions 24 and 26 may be connected only at their respective flexible bending portions or arms 32 and disconnected at their rearward-most ends so that spring system may be formed from two discrete springs or spring portions — one at the lateral side and the other at the medial side of the shoe, with their distal rearward ends anchored to the upper portion and sole, respectively.

As best seen in FIG. 5, in the illustrated embodiment, each spring portion 24 and 26 has a generally U-shape (as viewed in plan view) and as noted above is joined at its proximal ends to the proximal ends of the other of the spring portion 24 or 26, which together form a generally C- shaped spring on one side (lateral side) of the footwear and a reverse generally C-shaped spring on the other side (medial side) of the footwear, which are connected at their base by a transverse beam 34 in the form of a plate 36. Transverse beam 34 may extend under the rearward portion of sole 16 or may be integrated with the sole, such as by injection molding. Alternately, as described in reference to FIG. 12, the spring may include a reverse C-shaped spring portion at the lateral side of the footwear and a C-shaped spring portion at the medial side.

As noted above, the proximal ends 24a, 26a of the U-shaped spring portions 24 and 26 form flexible bending arms 32 at the medial and lateral sides of the shoe. In the illustrated embodiment, the proximal ends 24a, 26a of the spring portions 24 and 26 are forked or bifurcated to form a pair of nested and generally parallel generally C-shaped spring arms; however, the number of flexible bending arms may be varied. As described below, for example, three or more C-shaped or reverse C-shaped spring arms that form flexible bending arms may be provided.

Each U-shaped spring portion 24 and 26 has a tapered cross-section that increases along its length starting from the distal or rearward end of the spring portion 24, 26 to their respective proximal ends where the springs are forked into two spaced apart spring amis or portions 24a, 26a. Each spring aim or portion 24a, 26a therefore has a reduced cross-section than the cross- section of the portion of the spring adjacent where the fork occurs. With this configuration, spring 22 offers the similar or greater deflection as provided in the springs in U.S. Patent Nos. 6,557,271 and 6,964,119, but has reduced strain because the strain is less concentrated; hence, spring 22 is believed to provide an improved deflection curve and more evenly distribution stresses and strains throughout the body of the spring.

As best understood from FIGS. 1, 2, 3A and 3B, sole 16 includes a forward or toe sole portion 38 and rearward portion 30. In the illustrated embodiment, sole portion 30 extends generally from the middle portion of the footwear to the heel area and, further, is spaced below the heel portion 28 of upper portion 18. Referring to FIGS. 1 , 2, 3 A and .3D, energy storage system 12 may include a cushioning member 40 positioned between heel portion 28 of upper portion 18 and rearward portion 30 of sole 16. Cushioning member 40 may comprise a solid low density polyurethane body, or may comprise a hollow compressible polymeric body that forms an air bladder. Alternately, cushioning member may comprise a molded plastic bladder, such as from a thermal formed plastic, including TPU (thermal polyurethane) and may be molded by injection molding or blow molding. In addition, the bladder may be filled with a liquid or pressured fluid, including pressurized air or other gas, or filled with a gel. Further, the bladder may include a core formed from another compressible body, such as another bladder or a gel or foam body. In addition, when formed as a gas filled bladder, such as an air bladder, the pressure in the bladder may be adjustable. For example, the bladder may have a valve that releases the pressure when the pressure has exceeded a desired, preselected pressure.

Alternately or in addition, the valve may be an adjustable valve that can be adjusted manually or controlled by a microprocessor based control to control the resistance and the deflection of the suspension system. Alternately, the compressible body may comprise a foam body or a structural gel body. In this manner, energy storage system 12 may include two distinct energy absorbing members, such as spring 22 and cushioning member 40. Furthermore, the energy absorbing members may be arranged such that one of the energy absorbing members may provide the dominant resistance over one or more discrete ranges of motion of the footwear.

For example, spring 22 may provide the majority of resistance over a first range of motion or angular rotation, while cushioning member 40 may provide the majority of resistance over a second range of motion or angular rotation, which is due to both the shortening or the moment arm of the spring and the increased additional resistance of the compression and deformation of the cushioning member 40. For example, spring 22 may provide the majority of the resistance over the first range of motion where heel portion 28 of upper portion 18 deflects from its initial unloaded state to an initial loaded state where heel portion 28 deflects. Cushioning member 40 may then provide the majority of resistance over a later, second range of motion when heel portion 28 deflects further from the initial loaded state. In this manner, cushioning member 40 provides the majority of the resistance over the latter range of motion after spring 22 has deflected. Further, as will be more described below, cushioning member 40 itself may be configured to provide a first resistance over a first range of motion and a second, greater resistance over a second range of motion.

Referring again to FIG. 1 , body 40 may include one or more wedge-shaped recesses 42, which reduce the stiffness of body 40 over its initial range of motion. For example, body 40 may have an accordion-shaped body with multiple wedge-shaped recesses, such as shown and described in reference to FIG. 4. Once body 40 folds about the wedge, and the wedge essentially closes, the stiffness of body 40 is then a function of the compressibility of the body rather than from the folding of the body. In this manner, the resistance provided by body 40 is much lower while the wedge is closing so that spring 22 will provide most, if not all, the resistance over the first range of motion. However, when the wedge is closed, compressible body 40 is stiffer than the spring and may be the dominant source of resistance over this latter range of motion.

Similar to the energy storage system described in U.S. Patent No. 6,557,271 and 6,964,119, energy storage system 12 may convert at least some of the impact forces into propulsion forces by returning a portion of the heel strike energy back into the initial forefoot push-off direction (a.k.a. the active portion of the walk run gait). When a wearer is running and entering the first phase of the running profile, upper portion 24 of spring 22 will deflect relative to lower portion 26 and, further, will deflect about flexible bending arms 32. The impact force will cause heel portion 28 of upper portion 18 to compress cushioning member 40 and urge upper portion 24 to move close to lower portion 26. As upper portion 24 deflects about flexible bending arms 32, lower portion 26 will flatten and flexible bending arms 32 will roll forward. As upper portion 24 continues to deflect and body 40 folds to close wedge-shaped recess 42, body 40 and spring 22 will compress until such time that the reaction forces equal to the impact forces. Once the user's foot starts to then roll forward the impact forces will be removed and body 40 and spring 22 will rebound but because of the rolling motion of spring about flexible bending arms 32, upper portion 24 will generate a rebound force but at an angle that is counterclockwise (as viewed in FIG. 1) from the original impact force so as to create a forward propulsion force on the user's foot. In this manner, the spring rolls forward during the absorption of the impact forces, and then releases the stored energy, for example, in a direction generally vertically and into the direction of forward momentum of the user. In other words, as the wearer continues to roll forward unto the forefoot, the spring will be so shaped as to create a zero deflection point at a location somewhere between the beginning or end of the forefoot pad location. This insures a smooth transition of forces from the rear suspension system, unto the forefoot without creating any undesirable force or deflection spikes or irregularities in a continuous and consistent transfer body weight and related internal forces. This creates a tapered deflection wedge with a zero deflection of sole suspension taking place somewhere below an area at or near the forefoot of said shoe. As would be understood, therefore, the vertical and forward components of the released energy can be varied as desired to customize the footwear to the ultimate user's needs. Therefore, in addition to reducing, if not eliminating, the moment forces on the ankle, the energy recovery system can enhance the performance of the user of footwear 10.

In addition, it should be understood that the energy storage members may be adjusted to produce a profile that becomes progressively stiffer as the runner's foot rotates through a stride, as described above, or a profile that becomes progressively less stiff, or a profile that starts soft and becomes stiffer then softens. For example, the cross-section of the spring 22 may be varied along its length. Further, as noted, cushioning member 40 may include an inner core that has a different stiffness than the air or material surrounding the core. It should also be noted that the spring may be modified to provide a different response profile on each side of the shoe to provide, for example, asymmetrical spring resistances, for example, to create an asymmetrical loading response to address corrective measures similar to conventional orthotics that assist in correcting the asymmetrical forces within the wear's foot. In contrast to conventional running shoes, as noted above, footwear 10 lias a non-planar bottom sole 16. In the illustrated embodiment, sole 16 includes a curved bottom surface at its rearward portion 30, which allows the user to run with much less or no ankle rotation. The curved rear sole portion also eliminates premature heel strike and delays the heel strike until later in the running stride; thus reducing the "passive" contact phase of the contact stride

(proportionally to the "active phase of conventional footwear). As a result, the heel strike forces are moved forward on the foot into the mid-foot zone where the forces are more evenly distributed over the foot. Furthermore, by moving the heel strike forces forward, these forces are moved into the active phase of running. The reversed spring with the open end of the C- shaped facing forward will further delay the initial heel contact, and also allow for an even more efficient delivery of the stored heel strike energy even further on into the active forefoot push- off phase. As a result, the runner expends less energy in the passive phase and, instead, applies more of the energy in the active phase. In addition, the curved portion of sole 16 allows for a contact point of varying length to continually change the distance with respect to the anchor point or attachment point of spring 22 to upper portion 18. The curved sole also allows sole 16 to deflect over a prescribed region of the sole. The curved sole also moves initial contact forward from wearer's heel, to a position in front or forward of the heel, thus moving initial contact forward into the 'active' phase of foot/ground contact. This allows the wearer more control of contact forces now located further into contact phase. This reduction of 'passive phase' of foot contact may lead to reduction of potential injury, due to the fact that ankle injuries are more likely to occur or begin in 'passive' contact phase. Other benefits provided by the curve portion include a reduction or elimination in heel contact with the ground while the user is rotating from a forefoot contact to an initial heel contact, typically known as heel scuffing or "catching of the heel". As best seen in FIG. 4, in another embodiment of cushioning member 40', cushioning member 40' includes a plurality of wedge-shaped recesses 42' to form an accordion-shaped body. In this embodiment, therefore, the stiffness is more a function of the folding of the body rather than compressibility of the body.

Referring again to FIGS. 1 and 2, heel portion 28 may be reinforced by a heel cup 28a. Heel cup 28a may be formed from a fabric or a plastic molded paint. Further, as best seen in FIG. 5A, heel cup 28a may be molded with spring 22. For example, spring 22 may be over molded onto heel cup 28a to provide an optionally removable and replaceable spring unit.

Referring to FIGS. 7, the numeral 122 generally designates another embodiment of the spring of the present invention. Spring 122 is of similar construction to spring 22 and includes an upper portion 124, for extending around and mounting to the heal portion of the shell, and a lower portion for extending around and mounting to the rearward portion of the sole. For details of the material and optional methods of forming the spring reference is made to the first embodiment.

In the illustrated embodiment, the proximal ends 124a, 126a of the respective upper and lower portions 124, 126 are similarly forked or trifurcated with three arms, which are joined to form flexible bending arms 132 similar to flexible bending arms 32. It should be understood that other "multifurcated" configurations may be used (e.g. four, five, or more bending arms). The cross-section of upper and lower portions 124, 126 increase along their lengths from their distal or cantilevered ends to the juncture of trifurcation, at which point the thickness or cross- section of the spring is at a maximum. The cross-section of the arms 124a, 126b are generally uniform along their lengths and together may have a total cross-sectional area or thickness that is greater than the cross-section or thickness of the spring adjacent the fork.

By providing trifurcated spring portions, upper portion 124, 126 has greater flexibility about the flexible bending arms and will exhibit greater rolling when the user shifts his or her body weight forward, which may be more suitable in a running application of the footwear. Furthermore, spring 122 will initially generate a softer response than that of spring 22.

Referring to FIG. 11, the numeral 214 generally designates another embodiment of the spring system 214 of the present invention. Spring system 214 incorporates a pair of forwardly facing C-shaped spring portions 224 and 226 at the respective sides of the upper portion 218 and sole 216. Therefore, in the present embodiment, the lateral side of the footwear includes a reverse C-shaped spring portion, and the medial side of the footwear includes a generally C- shaped spring portion. Similar to the second embodiment, spring portions 224 and 226 include nesting flexible bending arms 224a and 226a, which are nested to form an outer flexible bending arm, a medial flexible bending arm, and an inner flexible bending arm, with each spaced apart to form a gap or opening that extends through the spring portions. Por details of the material and optional methods of forming the spring reference is made to the first embodiment.

With the forwardly facing C-shaped spring portions, the springs further delay the initial heel contact and also allow for an even more efficient delivery of stored heel strike energy, which is even further into the active four foot push-off phase. As a result, the runner expends less energy in the passive phase and instead applies more energy in the active phase. Again, the number of flexible bending arms may be decreased or increased to adjust the responsiveness of the spring portions. As described in reference to the previous embodiment, the gaps or openings may be modified, e.g. may incorporate a spring more springs, to adjust the overall characteristics of the spring.

It has been found that footwear of the present invention produces a significantly reduced impact force to a wearer or user of the footwear. Further, with the nesting arrangement of the flexible bending arms the gaps or openings formed between the flexible bending arms allow the outer bending amis to move or deflect toward the inner most bending arm and in to somewhat shorten its length, which reduces the strain on the bending arms outer fibers. The gap, space, or opening, however, can be adapted to control how much the outer bending arm or amis move or deflect, which again, can be used to control or modify the springs stiffness/resistance. For example, these gaps or openings may be filled with a compressible material, which form a spring. Alternately, or in addition, springs may be positioned between one or more of the respective bending arms. These "inserts" may be configured to be removable to allow customization. The gap may be filled by a bladder, which again provides a spring and which may be adjustable.

Referring to FIG. 12, the numeral 22' designates another embodiment of the spring of the present invention. Spring 22' is similar to spring 22 but may include an upper U-shaped spring portion 24' that has a steeper angle relative to lower U-shaped portion 26' and, therefore, may have a greater range of motion, for example, than spring 22. For details of the material and optional methods of forming the spring reference is made to the first embodiment.

At the same time, inner spring portion 24a', which forms the upper part of an inner arm 25a', has a greater cross-section than inner spring portion 26a', which forms the lower part of inner bending arm 25a' to reduce the bending at the upper part of inner bending arm 25a' . With this increase in stiffness and less bending, it has been found that the stresses in spring 22' are more uniformly distributed across the spring as shown in FIG. 12B.

While upper portion of inner bending arm 24' has increased stiffness due to its larger cross-section, lower portion 26a' of inner bending arm 25a' retains its flexibility much like in spring 22 so that both the outer bending arm 25b' and lower portion 26a' of bending arm 25a' still exhibit significant flexing, as shown in FIG. 12 A. Consequently, depending on the degree of stiffness, spring 22' may have three arm portions that flex (arm portions 24b', 26b', and 26a') and one ami portion that remains substantially constant, though it does move closer to lower arm portion 26b' of outer bending ami 25b' when spring 22' is compressed.

From the forgoing it can be appreciated that the footwear of the present invention provides an energy storage system reduces the effect of impact forces on the user's joints, including knees and that may reduce the risk of ankle sprain and injury. The footwear decouples the lateral forces from the vertical forces so that the lateral forces can be transferred above the bottom of the heel and preferably to or near to the height of the ankle joint centroid, thus reducing or eliminating the risk of overturning moments in the ankle that can cause injury while at the same time allowing the ankle to maintain its full range of motion. In addition, the present invention provides both linear elastic and non-linear cushioning members to allow engineering of the impact curve of the shoe. Thus, the footwear of the present invention may provide a low impact walking shoe that can be engineered to have an impact curve with a minimized maximum force observed, for example, by creating a square impact curve. The invention also provides a footwear that produces a low heel strike or a footwear that produces an impulse at the forefoot.

Additionally, it should be understood that the resistance provided by any of the springs of the present invention may be varied considerably based on the material properties and cross- section and other geometric properties of the springs. For example, the resistance provided by any one of these springs may range from about 30% of the user's weight to 500% or more of the user's weight depending on the application. For a walker, the resistance could be lower. Further, the pressure in the bladders may be varied as well. For example, the pressure in the bladder may range from 0 psi to 150 psi or 200 psi or more. Referring to FlG. 13, the numeral 310 designates another embodiment of the shoe or article of footwear of the present invention. In the illustrated embodiment, footwear 310 comprises an athletic piece of footwear; however, as mentioned above in reference to the other embodiments, it should be understood that various aspect of the footwear of the present invention may be incorporated into other types of footwear, including therapeutic footwear or everyday use footwear. As will be more fully described below, footwear 310 incorporates a fluid movement system that increases circulation of fluid, typically air, through the footwear to cool the user's foot. Optionally, the fluid movement system may include a heating and/or cooling device that heats or cools the fluid as it is circulated by the fluid movement system. Footwear 310 includes a sole 314 and an upper portion 316, which at least partially encloses the foot of the wearer. Sole 314 is formed from a flexible impact absorbing material, such as rubber. However, a wide variety of materials may be used to form sole 314. Furthermore, as will be more fully described below, sole 314 may incorporate one or more passageways 324 through the sole for distributing airflow through the footwear or may incorporate a bladder, each with one or more openings or perforations 324a through the sole to direct airflow into the foot cavity of the upper portion 316.

Upper portion 316 forms a shell, which surrounds at least a portion of the foot and may be made from a lightweight conventional material or textile, such as fabrics, leather, suede, or a combination of one or more of the above as is known in the art. Upper portion 316 may include cushioning material, such as neoprene foam or open celled foam, which may be positioned to evenly distribute forces from the foot to the shell by upper portion 316. Further, footwear 310 optionally may incorporate an energy storage system such as described in the previous embodiments or as described in commonly owned U.S. Pat. Nos. 6,557,271 and 6,964,119, which are incorporated by reference herein their entireties. Upper portion 316 may also incorporate passageways 324 with openings or perforations that face inwardly into the foot cavity. It should be understood that the location of the passageways may be varied and, further the number and length of the passageways may be varied. Similarly, the number of openings 324a may be varied. As best seen in FIG. 13, positioned between heel portion 316a of upper portion 316 and heel portion 314a of sole 314 is a compressible reservoir or bladder 318. Bladder 318 may be formed from a plurality of flexible materials, including rubber. Alternately, bladder 318 may comprise a molded plastic bladder, such as from a thermal formed plastic, including TPU (thermal polyurethane) and may be molded by injection molding or blow molding.

In the illustrated embodiment, bladder 318 has an accordion-shaped configuration, which forms a plurality of folds to allow bladder 318 to compress and extend in a generally linear and vertical path, As noted above, footwear 310 incorporates an air movement system. In the illustrated embodiment, air movement system 320 includes bladder 318 and an inlet valve 322, which is in fluid communication with bladder 318 and which provides a one-way valve to allow air to flow from outside footwear 310 to inside bladder 318 when the pressure in bladder 318 is below a predetermined pressure level. In this manner, the outside air acts as a fluid supply reservoir. Further, bladder 318 is provided with a biasing member, such as a spring, which biases bladder 318 in its uncompressed configuration and which is compressed when the user applies pressure at the heel 316a of upper portion 316. When the user ' s foot rolls forward in the footwear, and the heel removes reduces or removes the force on bladder 318, the biasing member will return the bladder to at least a partially uncompressed configuration. hi addition, bladder 318 further includes an exhaust valve 326. As referenced above, air movement system 320 also includes ducting or one or more passageways 324, which are in fluid communication with bladder 318 through valve 326 and which distribute air through the footwear when air is exhausted from bladder 318. In this manner, when bladder 318 is compressed under the load of the user applying force to the heel portion 316a of upper portion 316, bladder 318 will compress to exhaust the fluid (typically air) contained in bladder 318 through valve 326 into passageways 324. Once the air is exhausted from bladder 318 and the user releases the downward force on bladder 318, bladder 318 will be expanded as a result of the biasing force of biasing member, which will generate a vacuum force in bladder 318 and thereby cause valve 322 to open and permit air to enter into bladder 318. In this manner, bladder 318 is a self-filling bladder.

The biasing member may comprise a spring that is either inside or outside of the bladder and may comprise, for example a porous foam body located in bladder 318.

As noted above, footwear 310 includes one or more passageways 324 that extend through the footwear to distribute the air exhausted from bladder 318. For example, in the illustrated embodiment, a pair of passageways 324 are provided that extend through and are incorporated into the upper portion of upper portion 316 of article 310. The number of openings or perforations from the passageways into the inwardly facing side of upper portion 318 may vary depending on the size of the shoe, the desired airflow, or the like. Further, in the illustrated embodiment, one or more of the passageways may extend across the toe portion of the upper portion to provide airflow to the toe region of the user's foot. As noted, passageways 324 may extend through sole 314 with the openings or perforations providing fluid communication between the passageways and the foot cavity.

In addition to providing air movement, the air movement system may also incorporate a heating and/or cooling device. The cooling device may comprise a heat pump, which will take the hot compressed gas/liquid and then direct it through an externally mounted condensing coil section. TMs condensing coil will have an insulation layer placed between it and the outer of the footwear in order to minimize the amount of heat infiltration from the condensing coil back directly to the wearer's foot or leg. The goal of the condenser coil is to transfer heat within the compressed (high pressure) coolant to the outer casing of the coil, and then into the outside surrounding air, using a series of typical radiator fins that create a large amount of surface area for the surrounding air to come into contact with the hot casing for effective heat transfer. Further, an expansion valve may be provided between the condenser coil and the evaporation coil in order to create a high-pressure zone within the condenser coil, and a low- pressure zone within the evaporation coil. This component may be provided anywhere within or upon the shoe sole or upper portion. When coolant leaves the expansion valve, it then enters the low-pressure evaporation coil and will then be transferred into a gaseous state seeking to absorb heat energy from its surroundings. Similar to the ventilation ducting component, the evaporation coil can be located anywhere throughout the perimeter of the wearer's foot in order for the coolant within the evaporation coil to absorb heat energy from within the wearer's footwear or directly from the wearer's foot. The evaporation coil can be located inside the shoe or integrated into the upper portion or sole of the footwear. Absorbed heat from within the footwear and the wearer's foot may be transferred back through the one-way valve located at the beginning of the loop system and back to the heel compressor (heat pump)/pneumatic air chamber ventilation and be compressed once again.

Typical to the general practice and design of heat pump systems, a coolant with favorable material properties for absorbing and ejecting large amounts of heat energy based upon its relative pressure difference from the condensing and evaporation coils, and the corresponding liquid and gaseous states. Industry standard coolants, especially environmentally sensitive coolants and Freon's, among other materials may be used, especially in a closed lop system where the supply reservoir is internal to the footwear. One option is to reverse valving on the ventilation and closed loop heat pump systems, which will allow for a reversal of airflow in the ventilation system and a reversal of the cooling system to become a heating system.

Instead of fresh air from outside, and distributed throughout the interior of the footwear and directly to certain areas of the foot, a reversal of the valving would pull hot moist air from inside of the footwear in and around the foot and eject outside of the shoe. By reversing the valving of the heat pump, it is possible to turn the condensing coil into an evaporation coil and visa versa. Inherently, it takes the wearer's foot pressure to operate the compressor/air chamber.

Referring to FIGS. 16, 16A, 16B, and 16C₅ the numeral 418 references another embodiment of a bladder. Similar to bladder 318, bladder 418 is positioned between the heel portion, for example, heal portion 316a of the upper portion of an article of footwear and the sole, e.g. heel portion 314a of sole 314. Also bladder 418 is formed, such as by molding, from a flexible resilient material, such as rubber, or may be molded from plastic such as described in reference to bladder 318. As best seen in FIG. 16B, bladder 418 has a first body portion 420 with an accordion-shaped configuration and a second body portion 422, which is wedge-shaped and further is hollow and in fluid communication with the chamber formed by first body portion 420 via an exhaust valve 424. A suitable valve is a check valve, which opens when the pressure in the chamber exceeds a predetermined pressure but closes once the pressure drops below a predetermined pressure. For example, the set points on the valve, may be adjusted manually, or may be controlled by a microprocessor based control. Wedge-shaped body portion 422 extends between the shell and sole and includes one or more openings through which fluid is directed into the footwear. Therefore, wedge-shaped body portion 422 forms a conduit and also as described below may be adapted to provide variable volume control. For example, the bladder may incorporate a volume control device that may be controlled manually or may be adjusted using a microprocessor-based control.

Again, referring to FIGS. 16A and 16B, bladder 418 may also have a check valve 426 at its air inlet 428 so that air is drawn into the bladder, for example, after the pressure in the bladder drops. For example, a suitable valve includes a check valve, which allows air to flow into the bladder when the pressure in the bladder drops, for example, below atmospheric pressure. TMs occurs when a compression force is applied to the bladder and the bladder compresses and exhausts air through valve 424. Once the compressive force is removed from bladder 418, the springs of the energy recovery system will cause the bladder to expand, but with much of the air, if not all the air, exhausted from the chamber. This expansion will cause a pressure drop in the bladder and cause valve 426 to open. Once check valve 426 opens, fluid flows into the chamber.

Referring to FIGS. 17A and 17B, as noted above, bladder 418 may optionally include a flow control device 430 located in wedge portion 422 that is in fluid communication with the outlet of valve 424.

Flow control device 430 may comprise a valve, such as a gate valve, a wedge valve, or any other type of valve that provides on/off and gated positions to thereby vary the flow between zero flow to a full flow and anywhere in between. Though it should be understood that an on/off valve could also be used, though it would not provide the same adjustment capability. Referring again to FIGS. 17A and 17B, device 430 includes an actuator 432, such as a lever arm, that is coupled to the flow restrictor 434, such as the valve ball or gate, and extends outwardly from the device to provide a manual lever to control the position of the flow restrictor. Optionally, the actuator may extend into a recessed portion of the lateral or medial side of the shoe where it can be moved by a user's finger. It may also simply project outwardly from the lateral or medial side of the article of footwear through a slot in the side of the footwear.

In alternate embodiment shown in FIGS. 18A and 18B, bladder 418 may incorporate a powered actuator 532. For example, actuator 532 may comprise a motor 534 with a drive gear 536 that drives a driven gear 538, which is coupled to the flow restrictor 434, to thereby move the flow restrictor. Motor 534 is powered by an energy source 540, such as a battery, including a rechargeable battery. The battery 540 may also be located in wedge portion 422. Motor 532 is actuated by a control 542, such as an on/off switch or button or the like, which is mounted so that they are accessible by the user, such as at the lateral or medial side of the footwear. It should be understood that motor 532 may also be controlled using a micro-processor based control system, which may include sensors to adjust the flow rate through device 430 based on one or more parameters detected at the footwear or based on external conditions, such as temperature, surface conditions etc. For example, the sensors may detect deflection of the spring (springs) of the suspension system to change the cushioning or energy return. Further, the microprocessor and its associated hardware may have stored therein preset or programmable profiles that a user may select between depending on their activity or interest.

For example, the microprocessor and programming may allow user to choose various settings of suspension performance, then the system will automatically adjust valve to account for desired performance as it correlates to changing loading from the user. For example, loading can vary due to user's weight and level of G-loading due to accelerations created from walking to running. For example, the G-loading may range from IG to 5 G.

Consequently, bladder 418, like bladder 318, can provide a cushioning or compression element that may also serve as a component of a ventilation system for an article of footwear. As would be understood from the previous embodiment, air exhausted from wedge- shaped body portion 422 is directed into channels or passageways formed in the article of footwear that direct air through one or more openings into the foot cavity or inside of the article of footwear to cool (or heat as noted in reference to the previous embodiment) the user's foot. hi any of these embodiments, the outlet venting may be internally or externally ducted in and around the article of footwear or through the forefoot cushioning and then up into the foot cavity of the article of footwear. While the inlet duct is shown in a raised location, it can also be located elsewhere, for example, including in the midsole adjacent the outlet venting. While several forms of the invention have been shown and described, other forms will now be apparent to those skilled in the art. For example, as described, the springs of the present invention may be formed from a polymer or a metal or a composite material including a fiber, such as a carbon fiber, reinforced composite material, or the like. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention which is defined by the claims which follow as interpreted under the principles of patent law including the doctrine of equivalents.

Claims

I claim:

1. An article of footwear comprising; an upper portion forming a shell, said shell having a heel portion and a toe region; a sole, said sole having a rearward portion and a forward portion; and a spring extending between said upper portion and said sole, said spring suspending said heal portion above said rearward portion and extending around said shell above said heel portion and extending around said sole at said rearward portion, and said spring having nesting spring portions at each of the medial and lateral sides of the article of footwear, said nesting spring portions being forward of said heel portion and said rearward portion.

2. The article of footwear according to claim 1, wherein said spring includes three nesting spring portions at each of said medial and lateral sides of the article of footwear.

3. The article of footwear according to claim 1, wherein said spring includes a generally U- shaped upper portion and a generally U-shaped lower portion, said upper portion of said spring wrapping around said shell above said heel portion, and said lower portion of said spring wrapping around said sole at said rearward portion.

4. The article of footwear according to claim 3, wherein said upper portion has a cross- section along its length, said cross-section increasing from its rearward end to its forward end adjacent said nesting spring portions.

5. The article of footwear according to claim 4, wherein each of said upper portion of said spring and said lower portion of said spring includes a proximal end, said proximal ends being multifurcated, and said multifurcated proximal ends of said upper portion being joined with said multifurcated ends of said lower portion to thereby form said nesting spring portions.

6. The article of footwear according to claim 1, further comprising a compressible body positioned between said heel portion of said shell and said rearward portion of said sole.

7. The article of footwear according to claim 6, wherein said compressible body includes a wedge-shaped recess wherein said compressible body initially folds and closes said wedge- shaped recess when a user applies a load to the heel portion of the shell.

8. The article of footwear according to claim 6, wherein said body comprises a compressible bladder.

9. The article of footwear according to claim 6, wherein said compressible body comprises a gel.

10. An article of footwear comprising: an upper portion, said upper portion forming a shell, said shell including a heel portion; a sole having a rearward portion spaced below said heel portion; a spring suspending said heel portion above said rearward portion; and a compressible body position between said heel portion and said rearward portion, said compressible body having a wedge-shaped recess wherein said compressible body folds about said wedge-shaped recess when a user applies a force at said heel portion which generates a first resistance over a first range of motion, and when said compressible body is folded about said wedge-shaped recess and said wedge-shaped recess is substantially closed said compressible body generates a second resistance greater than said first resistance.

11. The article of footwear according to claim 10, wherein said compressible body comprises a bladder.

12. The article of footwear according to claim 10, wherein said spring includes a generally U-shaped upper portion and a generally U-shaped lower portion, said upper and lower portions being joined at their respective proximal ends forward of said rearward portion of said sole to form flexible bending arms at lateral and medial sides of the footwear.

13. The article of footwear according to claim 12, wherein each of said proximal ends of said upper and lower portions of said spring are multifurcated and form said flexible bending arms.

14. An article of footwear having a medial side and a lateral side, said article of footwear comprising: an upper portion, said upper portion forming a shell, said shell including a heel portion; a sole, said sole having a rearward portion; at least two nested spring amis mounted at each of said medial and lateral sides of the footwear, each of said spring arms having an apex, said apexes forming flexible bending portions at said medial and lateral sides forward of said rearward portion of sole and forward of said heel portion of said shell.

15. The article of footwear according to claim 14, wherein said spring arms comprise three generally C-shaped or generally reverse C-shaped nested spring arms.

16. The article of footwear according to claim 15, wherein said spring arms at said lateral side are joined with said spring arms at said medial side.

17. The article of footwear according to claim 14, further comprising a compressible member positioned between said heel portion of said shell and said rearward portion of said sole.

18. The article of footwear according to claim 17, wherein said compressible member comprises a compressible bladder.

19. An article of footwear comprising: an upper portion, said upper portion forming a shell, said shell including a heel portion; a sole, said sole including a rearward portion; and a spring mounted to said upper portion and said sole, said spring having inner and outer flexible bending amis at medial and lateral sides of said upper portion and said sole, said outer flexible bending arms being spaced from said inner flexible bending arms and forming a gap therebetween, when loaded said outer flexible bending arms bending and moving toward said inner flexible bending arms to thereby reduce the strain on the outer fibers of the outer flexible bending arms.

20. The article of footwear according to claim 18, wherein said spring comprises a unitary spring.

21. The article of footwear according to claim 19, wherein said rearward portion of said sole comprises a curved sole portion to form a rocker member.

22. An article of footwear comprising: a sole having a heel portion; an upper portion forming a shell for enclosing at least a portion of the user's foot therein, the upper portion having a heel portion; and a fluid movement system, the fluid movement system including a reservoir and a compressible bladder located beneath the heel portion of the upper portion wherein the bladder deforms from an uncompressed state to a compressed state under the application of a load at the heel portion of the upper portion, the fluid movement system further including a valve between the reservoir and the bladder, the valve permitting fluid flow from the reservoir to the bladder when the pressure in the reservoir is greater than the pressure in the bladder, the bladder having a discharge valve directing fluid into the upper portion or sole upon the application of the load at the heel portion thereby reducing the pressure in the bladder, and the fluid movement system further including a biasing member to generally at least partially return the bladder to its uncompressed state upon the removal of at least a portion of the load wherein a pressure lower than the pressure in the reservoir is generated in the bladder causing the inlet valve to open and permit fluid to enter into the bladder from the reservoir.

23. The article of footwear according to Claim 22, wherein the biasing member is located in the bladder.

24. The article of footwear according to Claim 22, further comprising at least one passageway in the sole and/or the upper portion, the passageway being in fluid communication with the exhaust valve and distributing the fluid exhausted by the bladder into the upper portion or sole.

25. The article of footwear according to Claim 24, further comprising a plurality of the passageway.

26. The article of footwear according to Claim 22, further comprising a heating or cooling device to heat or cool the fluid in the fluid movement system.

27. The article of footwear according to Claim 22, wherein the reservoir is located in the upper portion or the sole.

28. The article of footwear according to Claim 22, wherein the reservoir is located exteriorly of the upper portion and the sole.

29. The article of footwear according to Claim 22, wherein the reservoir is the air surrounding the footwear.

30. An article of footwear comprising: a sole, an upper portion, and a fluid movement system, the fluid movement system including a self-inflating bladder; a relief valve in communication with the bladder to release fluid from the bladder into the sole and/or the upper portion when pressure in the bladder exceeds a predetermined pressure; and an intake valve allowing fluid to enter the bladder when the pressure in the bladder is less than the pressure external of the footwear.

31. The footwear according to claims 30 further comprising a fluid passageway extending through the sole and/or the upper portion, the bladder exhausting fluid into the passageway for distributing fluid through the footwear.

32. The article of footwear according to Claim 30, further comprising a heating or cooling device to heat or cool the fluid in the fluid movement system.

33. An article of footwear comprising: a sole, an upper portion for at least partially enclosing a foot of a wearer of the footwear; and a heating/cooling system, the heating/cooling system including a heat sink, the heat sink drawing heat from a user's foot located in the footwear, and the heat sink being adapted to exhaust heat external to the footwear.

34. An article of footwear comprising: a sole; an upper portion for partially enclosing a user's foot; and a cooling system for cooling a user's foot located in the footwear.