Patent Publication Number: US-2022218067-A1

Title: Article of footwear having cushioning system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE 
     This application is a continuation of U.S. patent application Ser. No. 16/685,748 filed on Nov. 15, 2019, which is incorporated by reference herein in its entirety for all purposes. 
    
    
     BACKGROUND 
     Field of the Invention 
     The present disclosure relates to footwear, and more particularly relate to a sole and article of footwear having a fluid-filled bladder. 
     Background Art 
     The human foot possesses natural cushioning and rebounding characteristics. However, the foot alone is incapable of effectively overcoming many of the forces encountered during every day activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with every day activity is more acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters; muscle, tendon and ligament damage; and bone stress fractures. Improper footwear can also lead to other ailments, including back pain. 
     Proper footwear should complement the natural functionality of the foot, in part, by incorporating a sole, which absorbs shocks. Therefore, a continuing need exists for innovations in providing cushioning to articles of footwear. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure includes various embodiments of a sole for an article of footwear that provides a desired cushioning effect to a wearer&#39;s foot. 
     In accordance with one embodiment, a sole for an article of footwear comprises an upper sole; a fluid filled bladder coupled to the upper sole, the bladder comprising a plurality of chambers extending below the upper sole; and a plurality of recesses disposed between the upper sole and the bladder, and wherein the plurality of recesses each define an air pocket between the upper sole and the bladder. In some embodiments each of the recesses is disposed between a respective chamber and the upper sole. 
     In some embodiments, the plurality of chambers comprises a set of peripheral chambers exposed along a lateral side of the sole or a medial side of the sole. In some embodiments, each of the peripheral chambers comprises an upper chamber surface, a bottom chamber surface, and a chamber sidewall, and the upper chamber surface comprises a recess indented toward the bottom chamber surface. In some embodiments, each of the recesses is defined by a respective recess formed in the upper chamber surface of a respective peripheral chamber. 
     In some embodiments, the upper sole comprises a plurality of bulges disposed along the lateral side of the sole and the medial side of the sole. In some embodiments, the upper sole comprises a plurality of bulges disposed along the lateral side of the sole and the medial side of the sole. In some embodiments, each of the bulges comprises a convex-shaped exterior surface protruding outward from the sole. 
     In some embodiments, the side chamber surface of each peripheral chamber extends continuously from the exterior surface of a respective bulge. In some embodiments, each of the bulges comprise ribs extending in a vertical direction. In some embodiments, the chamber sidewall of each peripheral chamber comprises ribs extending continuously from the ribs of a respective bulge. 
     In some embodiments, the set of peripheral chambers includes a lateral row of peripheral chambers disposed along the lateral side of the sole and a medial row of peripheral chambers disposed along the medial side of the sole. In some embodiments, the upper sole comprises an exposed outer lateral edge disposed along a lateral side of the sole. In some embodiments, the bladder extends beyond the exposed outer lateral edge of the upper sole such that the lateral row of peripheral chambers forms a lateral sidewall of the sole. In some embodiments, the upper sole comprises an exposed outer medial edge disposed along a medial side of the sole. In some embodiments, the bladder extends beyond the exposed outer medial edge of the upper sole such that the medial row of peripheral chambers forms a medial sidewall of the sole. 
     In some embodiments, the plurality of chambers comprises a central heel chamber disposed in a heel region of the sole between the medial and lateral rows of chambers. In some embodiments, the bladder comprises a plurality of heel conduits fluidly connecting the central forefoot chamber to the medial and lateral rows of peripheral chambers located in the forefoot region of the sole. 
     In some embodiments, the plurality of chambers comprises a central heel chamber disposed in a heel region of the sole between the medial and lateral rows of peripheral chambers. In some embodiments, the bladder comprises a plurality of heel conduits fluidly connecting the central heel chamber to the medial and lateral rows of peripheral chambers located in the heel region of the sole. 
     In some embodiments, the upper sole comprises a flat bottom sole surface and a projection extending along the bottom sole surface and disposed between the medial and lateral rows of peripheral chambers. In some embodiments, the projection includes a projection wall engaging against at least one peripheral chamber disposed along the lateral side of the sole and at least one peripheral chamber disposed along the medial side of the sole. 
     In accordance with one embodiment, an article of footwear comprises an upper; and a sole coupled to the upper. In some embodiments, the sole comprises an upper sole; a fluid filled bladder coupled to the upper sole, the bladder comprising a plurality of chambers extending below the upper sole; and a plurality of recesses disposed between the upper sole and the bladder, wherein ambient air is disposed within the plurality of between the upper sole and the bladder. 
     In some embodiments, the bladder is comprised of a blow-molded elastomeric material such that the lateral and medial sidewalls formed by the peripheral chambers are flexible. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
       The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles thereof and to enable a person skilled in the pertinent art to make and use the same. 
         FIG. 1  shows a side view of an article of footwear according to embodiments. 
         FIG. 2  shows a rear view of an article of footwear according to embodiments. 
         FIG. 3  shows a bottom view of an article of footwear according to embodiments. 
         FIG. 4  shows a cross-section view of an article of footwear taken along line A-A in  FIG. 3  according to embodiments. 
         FIG. 5  shows a cross-section view of an article of footwear taken along line B-B in  FIG. 3  according to embodiments. 
         FIG. 6  shows a cross-section view of an article of footwear taken along line C-C in  FIG. 3  according to embodiments. 
         FIG. 7  shows a side view of a sole for an article of footwear according to embodiments. 
         FIG. 8  shows a perspective view of the upper sole for a sole according to embodiments. 
         FIG. 9  shows a bottom view of the upper sole for a sole according to embodiments. 
         FIG. 10  shows a bottom view of a bladder for a sole according to embodiments. 
         FIG. 11  shows a top view of a medial row of chambers for a bladder according to embodiments. 
         FIG. 12  shows a perspective view of a medial row of chambers for a bladder according to embodiments. 
         FIG. 13  shows a side view of a medial row of chambers for a bladder according to embodiments. 
         FIG. 14  shows a first perspective view of a lateral row of chambers for a bladder according to embodiments. 
         FIG. 15  a second perspective view of a lateral row of chambers for a bladder according to embodiment. 
         FIG. 16  is a cross-section view of an article of footwear taken along line C-C in  FIG. 3  according to embodiments. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present inventions will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings, in which like reference numerals are used to indicate identical or functionally similar elements. References to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     The following examples are illustrative, but not limiting, of the present inventions. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in the field, and which would be apparent to those skilled in the art, are within the spirit and scope of the inventions. 
     One attempt over the years to improve cushioning and resiliency of shoes is incorporating a multi-chamber pod in the shoe sole so that air is transferred between the heel and forefoot areas of a shoe during the wearer&#39;s gait motion. However, there are several difficulties associated with using a multi-chamber pod filled with pressurized fluid within a shoe sole. Namely, it is difficult to maintain consistent air pressure within the chambers of the pod due to leakage, thereby failing to provide the wearer&#39;s foot a stable cushioning effect. Consequently, performance of shoe soles employed with pressurized pods may be erratic at times, thereby compromising the performance of the shoe. 
     Unlike multi-chamber pods filled with pressurized fluid, fluid cushioning devices holding ambient air generally will not leak or lose as much as air due to the lack of pressure gradient between the fluid cushioning device and the ambient environment. However, shoe soles employing ambient air-filled fluid cushioning devices typically fail to provide the dynamic cushioning effects achieved by pressurized pods during the wearer&#39;s gait cycle. 
     Accordingly, there is a need for an improved fluid cushioning sole that provides dynamic cushioning support to the wearer&#39;s foot during the wearer&#39;s gait cycle, while still having pockets of ambient air disposed within the sole (e.g., fluid-filled bladder pod with air pockets) so that the shoe sole still provides a stable cushioning effect to the wearer&#39;s foot during limited foot movement. 
     According to various embodiments described herein, the sole of the present disclosure may overcome one or more of the deficiencies noted above by comprising an upper sole, a fluid-filled bladder coupled to the upper sole, and one or more recesses disposed between the upper sole and the bladder. One or more of the recesses defines an air pocket between the bladder and the upper sole. The recesses and the chambers of the bladder together provide a desired cushioning effect to the wearer&#39;s foot, while maintaining a stable fluid transfer between the chambers of the bladder. 
       FIGS. 1-7  illustrate an article of footwear  10  having an upper  20  and a sole  100  coupled to the upper  20  according to one embodiment of the present disclosure. In various embodiments, sole  100  may include a heel region  101 , a midfoot or arch region  102 , and a forefoot region  103  extending between a lateral side  104  and a medial side  105  of sole  100 . In some embodiments, as shown in  FIG. 1 , for example, sole  100  may include an upper sole  110  coupled to upper  20  and a bladder  120  disposed below and coupled to upper sole  110 . In some embodiments, sole  100  may include a lower sole  130  is disposed below and coupled to bladder  120 . In various embodiments, bladder  120  may include a pod assembly of fluid-filled chambers fluidly connected in series such that bladder  120  allows the stored fluid to flow in a manner complementary to the wearer&#39;s stride and to the forces applied to the anatomical structure of the wearer&#39;s foot. 
     In various embodiments, as shown in  FIGS. 4-6  for example, sole  100  may include a plurality of recesses  140  disposed between upper sole  110  and bladder  120 . In various embodiments, each recess  140  defines an air pocket disposed between upper sole  110  and bladder  120 , such that ambient air is disposed within each recess  140 . In various embodiments, the air pockets defined by recesses  140  provide a stable cushioning effect to the wearer&#39;s foot. In some embodiments, recesses  140  may be extended into bladder  120  to define air pockets between upper sole  110  and bladder  120 . In some embodiments, recesses  140  may be extended into upper sole  110  to define air pockets between upper sole  110  and bladder  120 . In some embodiments, recesses  140  may be extended into both upper sole  110  and bladder  120  to define air pockets between upper sole  110  and bladder  120 . In various embodiments, each recess  140  is disposed entirely within a perimeter of bladder  120  so that ambient air disposed in recess  140  may act in concert with pressurized air held in bladder  120  to provide a desired cushioning effect to wearer&#39;s foot. 
     In various embodiments, the arrangement, size, and shape of the recesses  140  may be adapted to provide a desired cushioning effect to a wearer&#39;s foot and stabilize air flow within bladder  120 . In various embodiments, upper sole  110  and bladder  120  may be adapted to alter the arrangement, size, and shape of the recesses  140 , as described herein. 
     In some embodiments, with reference to  FIGS. 1 and 2 , for example, upper sole  110  may be attached to the upper  20  by adhesive bonding, welding, or any other suitable technique. In some embodiments, as shown in  FIGS. 4-6 and 8 , for example, upper sole  110  may include a top surface  112  generally shaped to accommodate the contours of the foot. In some embodiments, as shown in  FIGS. 4-6 and 9 , for example, upper sole  110  may include a flat bottom surface  113  and one or more projections  114  formed along bottom surface  113 . In one embodiment, as shown in  FIG. 9 , for example, upper sole  110  may include a single projection  114  extending from along bottom surface  113  from heel region  101  to the forefoot region  103 . In some embodiments, projection  114  may include a projection wall  115  sized and shaped to engage a portion of bladder  120  (e.g., a chamber of bladder  120 ). In some embodiments, projection  114  may define a ground-contacting surface comprising ridges  114 A protruding downward away from sole  100  to increase strength of projection  114 . 
     In some embodiments, as shown in  FIGS. 1, 2, 4-6, 8, and 9 , for example, upper sole  110  may include a plurality of bulges  116  disposed along lateral side  104  and medial side  105  of sole  100 . In some embodiments, with reference to  FIGS. 1, 2, 4-6, and 8 , each bulge  116  may comprise a convex-shaped exterior surface  117  protruding outward from sole  100 , where bulges  116  disposed along lateral side  104  of sole  100  define an exposed outer lateral edge  117 A and bulges  116  disposed along medial side  105  of sole  100  define an exposed outer medial edge  117 B. In some embodiments, as shown in  FIGS. 1 and 8 , for example, bulges  116  may define a corrugated-shaped upper edge  118  extending from heel region  101  to forefoot region  103  of sole  100 . In some embodiments, as shown in  FIGS. 1, 2, and 8 , for example, plurality of bulges  116  comprise ribs  119  protruding from exterior surface  117  and extending in a vertical direction. In some embodiments, ribs  119  are configured to increase stiffness of the sides of the upper sole  110 . 
     In various embodiments, upper sole  110  may be comprised of a foam material, such that the upper sole  110  is configured to absorb shock and provide cushion to wearer&#39;s foot. In some embodiments, upper sole  110  may be comprised of a foam-based material that includes ethylene vinyl acetate (EVA). In some embodiments, upper sole  110  comprises thermoplastic urethane (TPU). In some embodiments, upper sole  110  comprises expanded thermoplastic foam, such as, for example, expanded thermoplastic urethane (eTPU). In embodiments, upper sole  110  may be comprised of a foam-based material that includes materials, such as elastomers, thermoplastic elastomers, foam-like plastic, and gel-like plastics. In some embodiments, upper sole  110  may be comprised of an open-cell foam-based material or a closed-cell foam-based material. 
     In various embodiments, bladder  120  may be comprised of an elastomeric, resilient material and filled with a fluid such that bladder  120  is configured to compress upon the application of force and expand with the delivery of a fluid, thereby providing continuous cushioning support for wearer&#39;s foot. In some embodiments, bladder  120  may be fluid-filled. In some embodiments, bladder  120  is filled with ambient air. In some embodiments, bladder  120  may be filled with air set at a pressure above ambient pressure, such as, for example, in a range between 4 psi and 8 psi above ambient pressure. In some embodiments, bladder  120  may be filled with other types of gases, such as helium or nitrogen. In some embodiments, bladder  120  may further be filled with other materials, such as, for example, a gel, a paste, foam, a plurality of particles (e.g., polymer particles, eTPU particles, foam particles, cellulose particles, rock, or rubber particles), or a combination thereof. In various embodiments, bladder  120  may provide continuous cushioning to the wearer&#39;s foot such that a wearer&#39;s stride forces the fluid (e.g., air) or material (e.g., foam particles) within bladder  120  to flow in a manner complementary to the wearer&#39;s stride. 
     In some embodiments, bladder  120  may be comprised of a thermoplastic elastomer or a thermoplastic polyurethane. In other embodiments, bladder  120  may be comprised of other materials suitable for providing elastomeric, resilient properties, such as, for example, thermoplastic olefins, thermoplastic vulcanates, rubber, or a combination thereof. In some embodiments, bladder  120  may be formed by an extrusion blow-molded technique such that all the elements of the bladder  120 , as described herein, are provided as a unitary “one-piece” component. In some embodiments, the blow-molded technique for forming the bladder  120  may include injection blow molding, stretch blow molding, or frame blow molding. In other embodiments, bladder  120  may be formed by other processes, such as, for example, thermoforming and sealing, injection molding and sealing, vacuum forming and sealing, or radio frequency/high frequency welding. 
     In various embodiments, with reference to  FIG. 10 , for example, bladder  120  comprises a plurality of fluid-filled chambers  121 ,  123 ,  125  extending below upper sole  110 . In various embodiments, bladder  120  comprises a plurality of peripheral passages  122 , a plurality of forefoot conduits  124 , and a plurality of heel conduits  126  fluidly connecting the plurality of chambers such that fluid (e.g., air) may be diffused between the various chambers upon the application of force against sole  100 . 
     In some embodiments, the plurality of chambers include a set of peripheral chambers  121  exposed along either lateral side  104  or medial side  105  of sole  100 . In some embodiments, each peripheral chamber  121  is located directly beneath a respective bulge  116  of upper sole  110 . In some embodiments, set of peripheral chambers  121  include a lateral row  127  of peripheral chambers  121  disposed along lateral side  104  of sole  100  and a medial row  128  of peripheral chambers  121  disposed along medial side  105  of sole  100 . In some embodiments, lateral row  127  and medial row  128  of peripheral chambers  121  extend from heel region  101  to forefoot region  103  of sole  100 . 
     In some embodiments, lateral row  127  and medial row  128  of peripheral chambers  121  are fluidly connected in series via peripheral passages  122  such that each pair of adjacent peripheral chambers  121  are interconnected by a respective peripheral passage  122 . In some embodiments, as shown in  FIG. 10 , for example, peripheral chambers  121  disposed at the forward most end of lateral row  127  and medial row  128  are each directly connected to only one peripheral chamber  121 . In some embodiments, as shown in  FIG. 10 , for example, peripheral chambers  121  disposed at the rearward most end of lateral row  127  and medial row  128  are directly connected together by a respective peripheral passage  122 . 
     In some embodiments, as shown in  FIG. 10 , for example, the plurality of chambers include a central forefoot chamber  123  disposed in forefoot region  103  of sole  100  between the lateral and medial rows  127 ,  128  of peripheral chambers  121 . In some embodiments, plurality of forefoot conduits  124  are located in forefoot region  103  of sole  100  and fluidly connect central forefoot chamber  123  to at least one of peripheral chambers  121  disposed along the lateral row  127  and at least one of peripheral chambers  121  disposed along medial row  128 . In one embodiment, as shown in  FIG. 10 , for example, bladder  120  includes a total of four forefoot conduits  124  that fluidly connect central forefoot chamber  123  to two peripheral chambers  121  disposed along later row  127  and two peripheral chambers  121  disposed along medial row  128 . 
     In some embodiments, as shown in  FIG. 10 , for example, the plurality of chambers include a central heel chamber  125  disposed in heel region  101  of sole  100  between the lateral and medial rows  127 ,  128  of peripheral chambers  121 . In some embodiments, plurality of heel conduits  126  are located in heel region  101  of sole  100  and fluidly connect central heel chamber  125  to at least one of peripheral chambers  121  disposed along the lateral row  127  and at least one of peripheral chambers  121  disposed along medial row  128 . In one embodiment, as shown in  FIG. 10 , for example, bladder  120  includes a total of three heel conduits  126  that fluidly connect central heel chamber  125  to two peripheral chambers  121  disposed along later row  127  and a single peripheral chamber  121  disposed along medial row  128 . 
     In some embodiments, the plurality of chambers include a central midfoot chamber disposed in midfoot region  102  of sole  100  between the lateral and medial rows  127 ,  128  of peripheral chambers  121 . In some embodiments, the plurality of conduits include a set of midfoot conduits located in midfoot region  102  of sole  100  and fluidly connecting central midfoot chamber to at least one of peripheral chambers  121  disposed along the lateral row  127  and at least one of peripheral chambers  121  disposed along medial row  128 . 
     In some embodiments, the cross-section opening formed along selective portions of peripheral passages  122 , forefoot conduits  124 , and heel conduits  126  may be reduced to control air flow between adjacent chambers. In one embodiment, for example, a portion of peripheral passages  122  located in midfoot region  102  of sole  100  may include an orifice so that upon heel strike, air in peripheral chambers  121  along heel region  101  gradually flows to peripheral chambers  121  along forefoot region  103 , rather than flowing rapidly to peripheral chambers  121  along forefoot region  103 . In some embodiments, bladder  120  may include valves at various locations in peripheral passages  122 , forefoot conduits  124 , and heel conduits  126  to regulate air flow between portions of the sole  100 . In one embodiment, for example, valves may be disposed in peripheral passages  122  located in midfoot region  102  of sole  100  to substantially isolate the peripheral chambers in the heel region  101  of sole  100 . 
     In some embodiments, with reference to  FIGS. 4-6 and 11-15 , for example, each peripheral chamber  121  may include an upper chamber surface  210  disposed against bottom surface  113  of upper sole  110 , a bottom chamber surface  220  configured to engage a ground surface, and a chamber sidewall  230  extending from upper chamber surface  210  to bottom chamber surface  220 . In some embodiments, upper chamber surface  210  defines a substantially oval shape. In other embodiments, upper chamber surface  210  may define other round shapes, such as a circle. In some embodiments, bottom chamber surface  220  defines a convex, curved shape bulging away from bottom surface  113  of upper sole  110 . In some embodiments, chamber sidewall  230  defines a convex, curved shape bulging outwards, such that bottom chamber surface  220  and chamber sidewall  230  collectively define a rounded (e.g., semi-elliptical-shaped) edge that allows peripheral chamber  121  to gradually collapse under pressure. By gradually collapsing under pressure, peripheral chamber  121  forces stored fluid to flow to other locations along the bladder  120  while still providing cushioning support to wearer&#39;s foot. In some embodiments, sidewall  230  of each peripheral chamber  121  protrudes outward beyond outer lateral edge  117 A and outer medial edge  117 B of upper sole  110  to form a sidewall of sole  100 . 
     In various embodiments, the size and shape of chamber sidewall  230  may be adapted to increase the structural integrity of peripheral chamber  121 . For example, in some embodiments, chamber sidewall  230  comprises a transverse dimension (e.g. thickness) that is greater than a transverse dimension of either bottom chamber surface  220  and upper chamber surface  210 . In some embodiments, the transverse dimension of chamber sidewall  230  may range from about 0.8 mm to about 3.5 mm, such as from about 1.5 mm to about 2.5 mm. In some embodiments, the transverse dimension of chamber sidewall  230  may vary based on the material compound used to form bladder  120 . In some embodiments, the transverse dimension of chamber sidewall  230  may be set at a particular transverse dimension to provide a desired feel or effect to the wearer&#39;s foot. In some embodiments, chamber sidewall  230  includes ribs  234  protruding outward and extending in a vertical direction to increase the strength of chamber sidewall  230 . In some embodiments, ribs  234  of each chamber sidewall  230  extend continuously from the ribs  219  of a respective bulge  116 . In some embodiments, ribs  234  may be configured to add strength to bladder  120  so that bladder  120  may provide adequate against the wearer&#39;s foot while comprising less material and less weight. In some embodiments, the shape and design of ribs  234  may be configured to tailor cushioning characteristics provided by sole  100  according to a wearer&#39;s gait cycle. In some embodiments, the shape and design of ribs  234  may be configured to provide visual distinction or impact. 
     In various embodiments, the shape of peripheral chambers  121  may be adapted to promote snug contact with upper sole  110 , thereby ensuring a secure connection between bladder  120  and upper sole  110 . In some embodiments, as shown in  FIGS. 11-15 , for example, chamber sidewall  230  may extend above an outer edge of upper chamber surface  210  such that a groove  212  is defined along the outer edge of upper chamber surface  210 . In some embodiments, a portion of upper sole  110  may be received in groove  212 , such that upper sole  110  is partially contained by chamber sidewall  230 . In some embodiments, as shown in  FIGS. 11, 12, and 14 , for example, chamber sidewall  230  may include a shoulder  236  protruding away from an inner edge of upper chamber surface  210 . In some embodiments, a portion of projection  114  may engage shoulder  236  of sidewall  230  such that each peripheral chamber  121  is flushed against projection wall  115 . In some embodiments, projection  114  of upper sole  110  may be disposed between lateral row  127  and medial row  128  of peripheral chambers  121  such that projection wall  115  engages peripheral chambers  121  disposed along lateral and medial sides  104 ,  105  of sole  100 . 
     In some embodiments, with reference to  FIGS. 4-6 and 9 , for example, chamber sidewalls  230  of peripheral chambers  121  collectively define a corrugated-shaped upper edge  238  and a corrugated-shaped lower edge  239  that extend from heel region  101  to forefoot region  103  and corresponds to the shape of upper edge  118  defined by bulges  116  of upper sole  110 . In some embodiments, upper edge  238  of peripheral chambers  121  is disposed flushed against outer lateral edge  117 A and outer medial edge  117 B of bulges  116  such that chamber sidewall  230  of each peripheral chamber  121  extends continuously from exterior surface  117  of bulges  116 . In some embodiments, chamber sidewalls  230  of peripheral chambers  121  disposed along lateral row  127  protrude beyond outer lateral edge  117 A of bulges  116  such that lateral row  127  of peripheral chambers  121  form a lateral sidewall of sole  100 . In some embodiments, chamber sidewalls  230  of peripheral chambers  121  disposed along medial row  128  protrude beyond outer medial edge  117 B of bulges  116  such that medial row  128  of peripheral chambers  121  form a medial sidewall of sole  100 . 
     In some embodiments, as shown in  FIGS. 4-6 , upper chamber surface  210  includes a recessed portion  240  indented toward bottom chamber surface  220  such that bottom surface  113  of upper sole  110  and recessed portion  240  of upper chamber surface  210  collectively define the outer boundary of recess  140 . In some embodiments, recess  140  may hold ambient air held between recessed portion  240  of upper chamber surface  210  and bottom surface  113  of upper sole  110 . In some embodiments, the ambient air disposed in recess  140  may be at a pressure lower than the pressure of fluid held in bladder  120 . In some embodiments, peripheral chamber  121  may hold a volume of fluid (e.g., air) greater than the volume of ambient air held in recess  140 . 
     In some embodiments, ambient air disposed in recess  140  may act in concert with pressurized air held in peripheral chamber  121  to provide a desired cushioning effect to wearer&#39;s foot. For example, in some embodiments, recess  140  and peripheral chamber  121  may be configured to provide a dual phase cushioning system by the ambient air disposed in recess  140  providing a baseline cushion against the wearer&#39;s foot and the air stored in peripheral chamber  121  providing additional support against the wearer&#39;s foot. In some embodiments, air disposed in recess  140  may support upper chamber surface  210  such that the arrangement between recess  140  and peripheral chambers  121  provides a more stable platform. In some embodiments, the dual phase cushioning system furnished by recesses  140  and peripheral chambers  121  may provide a smoother and more supportive feel compared to previous single stage bladder systems. 
     In some embodiments, recessed portion  240  may define a shape corresponding to the shape (e.g., semi-elliptical) of bottom chamber surface  220 . In some embodiments, recessed portion  240  may define an opening along upper chamber surface  210  with a shape corresponding to the shape (e.g., oval) of upper chamber surface  210 . In some embodiments, recessed portion  240  may define other shapes, such as circular, semi-spherical, oblong, conical, tubular, parabolic, sinusoidal, tapered, sinusoidal, polyhedral (e.g., cubical), rounded, and trough. In some embodiments, recessed portion  240  is indented toward bottom chamber surface  220  by a predetermined depth in a range between about 4 mm and 10 mm so that an adequate volume of air may be disposed in recess  140 . In some embodiments, the depth of recessed portion  240  may be proportional to the size of peripheral chamber  121 . For example, in some embodiments, peripheral chambers  121  disposed along lateral and medial rows  127 ,  128  gradually increase in volume from forward-most peripheral chamber  121  to rearward-most peripheral chamber  121 , and a depth of recessed portion  240  may gradually increase in length from forward-most peripheral chamber  121  to rearward-most peripheral chamber  121 . 
     In some embodiments, upper chamber surface  210  of each peripheral chamber  121  may include a recessed portion  240  such that a recess  140  is defined between each peripheral chamber  121  and upper sole  110 . In some embodiments, recesses  140  may not be defined in one or more of the peripheral chambers  121  of bladder  120 . For example, in some embodiments, one or more peripheral chambers  121  may not include a recessed portion  240  in upper chamber surface  210  such that recesses  140  are not defined between selected peripheral chambers  121  of bladder  120  and upper sole  110 . In some embodiments, one or more peripheral chambers  121  located in heel region  101  of sole  100  may not include a recessed portion  240  so that more pressurized fluid may be held in heel region  101  of sole  100  to cushion against the stronger forces applied during heel strike. In one embodiment, the largest peripheral chamber  121  located in heel region  101  of sole  100  may not include a recessed portion  240  so that more pressurized fluid may be held in heel region  101  of sole  100 . 
     In some embodiments, a portion of upper chamber surface  210  surrounding recessed portion  240  may be inclined from edge of recessed portion  240  to outer and inner edges disposed against chamber sidewall  230 . In some embodiments, a portion of upper chamber surface  210  surrounding recessed portion  240  may be flat and level against bottom surface  113  of upper sole  110 . In some embodiments, upper surface  210  may comprise a ridge  211  defining the perimeter of recessed portion  240  and disposed between associated recess  140  and groove  212 . In some embodiments, ridge  211  protrudes above the remaining portions of upper surface  210 . 
     In some embodiments, as shown in  FIG. 16 , for example, bottom surface  113  of upper sole  110  may include recessed portions  113 A, such that the upper surface of bladder  120  and the recessed portions  113 A of bottom surface  113  of upper sole  110  collectively define the outer boundary of recess  140 . In some embodiments, the recessed portions  113 A of bottom surface  113  may be located directly above upper chamber surface  210  of each peripheral chamber  121 . 
     In some embodiments, recesses  140  may not be defined in one or more of the chambers of bladder  120 . For example, in some embodiments, central forefoot chamber  123  and central heel chamber  125  may each include an upper surface that does not comprise a recessed portion such that the substantially entire upper surface of central forefoot chamber  123  and central heel chamber  125  is flush against bottom surface  113  of upper sole  110 . In some embodiments, central forefoot chamber  123  and central heel chamber  125  may each include an upper surface that comprises a recessed portion such that the bottom surface  113  of upper sole  110  and recessed portions of the upper surface of central forefoot chamber  123  and central heel chamber  125 . 
     In various embodiments, the number, size, and shape of the plurality chambers  121 ,  123 ,  125  of bladder  120  may be varied to provide the desired ride characteristics. 
     In one embodiment, as shown in  FIG. 10 , for example, bladder  100  may include a total of four peripheral chambers  121  located in heel region  101  of sole  100  and six peripheral chambers  121  located in forefoot region  103  of sole  100 , whereby lateral and medial rows  127 ,  128  each include two peripheral chambers  121  disposed in heel region  101  and three peripheral chambers  121  disposed in forefoot region  103 . In other embodiments, bladder  120  may include any number of peripheral chambers  121  in heel region  101  and forefoot region  103  to provide desired support for wearer. 
     In some embodiments, as shown in  FIG. 10 , for example, peripheral chambers  121  located in heel region  101  are larger in volume than peripheral chambers  121  located in forefoot region  103 . In some embodiments, peripheral chambers  121  disposed along lateral and medial rows  127 ,  128  gradually increase in volume from forward-most peripheral chamber  121  to rearward-most peripheral chamber  121 . By providing larger volume peripheral chambers  121  in heel region and gradually increasing volume of peripheral chambers  121  from forefoot region  103  to heel region  101  of sole  100 , bladder  100  provides added support and cushioning in heel region  101  to account for larger downward force applied by wearer during the heel strike. 
     In various embodiments, peripheral chambers  121  may include a height in a range between about 7 mm to about 26 mm. In some embodiments, a ratio between height of recessed portion  240  and height of peripheral chamber  121  may range from about 15% to 60% so that an adequate volume of air is held recess  140  and sufficient strength is provided for peripheral chamber  121 . In various embodiments, peripheral chambers  121  may include a transverse dimension (e.g., diameter) in a range between about 25 mm and 60 mm depending on location of peripheral chamber  121  along sole  100 . For example, peripheral chambers  121  disposed in heel region  101  of sole  100  may comprise a larger transverse dimension than peripheral chambers  121  disposed in forefoot region  103  of sole  100 . 
     In some embodiments, central forefoot chamber  123  and central heel chamber  125  are each triangular in shape, as opposed to the more oval shape of peripheral chambers  121 . In some embodiments, central forefoot chamber  123  and central heel chamber  125  are each slightly flatter than the peripheral chambers  121  to account for the lack of force applied toward the center of wearer&#39;s heel upon heel strike as compared to amount of force applied against the outer edges of the wearer&#39;s heel. 
     In various embodiments, with reference to  FIGS. 1-6 , lower sole  130  is coupled to selected portions of a bottom surface of bladder  120  and/or projection  114  of upper sole  110 . In some embodiments, lower sole  130  may be coupled to only the bottom surface of chambers  121 ,  123 ,  125 , peripheral passages  122 , and forefoot and heel conduits  124 ,  126 , without being coupled to any portion of upper sole  110 . In some embodiments, lower sole  130  is coupled to both the bottom surface of chambers  121 ,  123 ,  125 , peripheral passages  122 , and forefoot and heel conduits  124 ,  126  and projection  114  of upper sole  110 . In some embodiments, lower sole  130  may comprise ridges  132  protruding downward away from sole  100  to increase rigidity and strength of lower sole  130 . 
     In some embodiments, as shown in  FIGS. 4-6 , for example, lower sole  130  may include an outer edge  134  extending along lateral side  104  and medial side  105  of sole  100 . In some embodiment, outer edge  134  of lower sole  130  may be corrugated-shaped and disposed flushed against lower edge  239  defined by chamber sidewalls  230  of peripheral chambers  121  such that an exterior surface of lower sole  130  extends continuously from chamber sidewalls  230  of peripheral chambers  230 . 
     In some embodiments, all or a portion of the lower sole  130  may comprise a wear-resistant material. For example, wear-resistant material for lower sole  130  may include synthetic or natural rubber, thermoplastic polyurethane, a wear-resistant foam, or a combination thereof. 
     In some embodiments, sole  100  may include an insole and/or sockliner disposed on top surface  112  of upper sole  110 . 
     The foregoing description of the specific embodiments will so fully reveal the general nature of the invention(s) that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention(s). Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance. 
     The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.