Patent Publication Number: US-11638463-B2

Title: Sole structure for article of footwear

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 62/937,462, filed Nov. 19, 2019, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     FIELD 
     The present disclosure relates generally to sole structures for articles of footwear, and more particularly, to sole structures incorporating a bladder. 
     BACKGROUND 
     This section provides background information related to the present disclosure, which is not necessarily prior art. 
     Articles of footwear conventionally include an upper and a sole structure. The upper may be formed from any suitable material(s) to receive, secure, and support a foot on the sole structure. The upper may cooperate with laces, straps, or other fasteners to adjust the fit of the upper around the foot. A bottom portion of the upper, proximate to a bottom surface of the foot, attaches to the sole structure. 
     Sole structures generally include a layered arrangement extending between a ground surface and the upper. One layer of the sole structure includes an outsole that provides abrasion-resistance and traction with the ground surface. The outsole may be formed from rubber or other materials that impart durability and wear-resistance, as well as enhance traction with the ground surface. Another layer of the sole structure includes a midsole disposed between the outsole and the upper. The midsole provides cushioning for the foot and may be partially formed from a polymer foam material that compresses resiliently under an applied load to cushion the foot by attenuating ground-reaction forces. The midsole may additionally or alternatively incorporate a fluid-filled bladder to increase durability of the sole structure, as well as to provide cushioning to the foot by compressing resiliently under an applied load to attenuate ground-reaction forces. Sole structures may also include a comfort-enhancing insole or a sockliner located within a void proximate to the bottom portion of the upper and a strobel attached to the upper and disposed between the midsole and the insole or sockliner. 
     Midsoles employing bladders typically include a bladder formed from two barrier layers of polymer material that are sealed or bonded together. The bladders may contain air, and may incorporate tensile members within the bladder to retain the shape of the bladder when pressurized. Generally, bladders are designed with an emphasis on balancing support for the foot and cushioning characteristics that relate to responsiveness as the bladder resiliently compresses under an applied load 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure. 
         FIG.  1    is a side perspective view of an article of footwear in accordance with principles of the present disclosure; 
         FIG.  2    is an exploded view of the article of footwear of  FIG.  1   , showing an article of footwear having an upper, a midsole, and an outsole arranged in a layered configuration; 
         FIG.  3    is a bottom plan view of the article of footwear of  FIG.  1   ; 
         FIG.  4    is a cross-sectional view taken along line  4 - 4  of  FIG.  3   , showing a bladder disposed in a heel region and having a peripheral chamber and an interior chamber separated by a web area; 
         FIG.  5    is a cross-sectional view taken along line  5 - 5  of  FIG.  3   , showing segments of a peripheral chamber of a bladder disposed within a heel region of the sole structure and separated from one another by a web area; 
         FIG.  6    is a cross-sectional view taken along line  6 - 6  of  FIG.  3   , showing a bladder having a peripheral chamber and an interior chamber separated by a web area; 
         FIGS.  7 A and  7 B  are bottom plan views of a bladder of the article of footwear of  FIG.  1   ; 
         FIG.  8    is a top plan view of the bladder of the article of footwear of  FIG.  1   ; 
         FIG.  9    is a side perspective view of an article of footwear in accordance with principles of the present disclosure; 
         FIGS.  10 A and  10 B  are bottom plan views of a bladder of the article of footwear of  FIG.  9   ; 
         FIG.  11    is a side perspective view of an article of footwear in accordance with principles of the present disclosure; and 
         FIGS.  12 A and  12 B  are bottom plan views of a bladder of the article of footwear of  FIG.  11   . 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION 
     Example configurations will now be described more fully with reference to the accompanying drawings. Example configurations are provided so that this disclosure will be thorough, and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that example configurations may be embodied in many different forms, and that the specific details and the example configurations should not be construed to limit the scope of the disclosure. 
     The terminology used herein is for the purpose of describing particular exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. Additional or alternative steps may be employed. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to,” “attached to,” or “coupled to” another element or layer, it may be directly on, engaged, connected, attached, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” “directly attached to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections. These elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example configurations. 
     In one aspect of the disclosure, a bladder for an article of footwear is provided. The bladder extends from an anterior end to a posterior end and includes a first chamber disposed in an interior region of the bladder and including a first interior void having a first pressure, and a second chamber at least partially surrounding the first chamber and including a second interior void having a second pressure. 
     Implementations of the disclosure may include one or more of the following optional features. 
     In some examples, the bladder has a first width adjacent to the anterior end of the bladder, a second width adjacent to the posterior end of the bladder, and a third width in an intermediate portion that is less than the first width and the second width. 
     In some configurations, the second chamber includes an anterior portion having a first cross-sectional area, a posterior portion having a second cross-sectional area, and an intermediate portion connecting the anterior portion and the posterior portion and having a third cross-sectional area. Here, the third cross-sectional area may be less than the first cross-sectional area. Optionally, the third cross-sectional area may be less than the second cross-sectional area. In some examples, the third cross-sectional area may be less than the first cross-sectional area and the second cross-sectional area. 
     In some implementations, the bladder includes a web area disposed between and connecting the first chamber and the second chamber. 
     In some examples, the bladder includes a first barrier layer and a second barrier layer joined together at discrete locations to define the first chamber and the second chamber. Optionally, at least one of the first barrier layer and the second barrier layer is transparent. In some examples, at least one of the first barrier layer and the second barrier layer is translucent. 
     In some configurations, the second chamber completely surrounds the first chamber. 
     In some examples, the second chamber partially surrounds the first chamber. 
     In some implementations, the second chamber includes a plurality of lobes, each lobe having a first end, a second end, and an intermediate portion disposed between the first end and the second end and being larger than the first end and the second end. Here, each lobe may taper from the intermediate portion to the first end and the second end. For each lobe, a thickness of the intermediate portion may be greater than thicknesses of the first end and the second end. Additionally or alternatively, for each lobe, a width of the intermediate portion is greater than widths of the first end and the second end. In some examples, a cross-sectional area of the intermediate portion is greater than the cross-sectional areas of the first end and the second end. Optionally, a plurality of the lobes are arranged in series around the first chamber. 
     In some examples, the plurality of lobes includes a medial anterior lobe and a lateral anterior lobe. Here, the medial anterior lobe and the lateral anterior lobe may be in direct fluid communication with each other. 
     In some implementations, the plurality of lobes includes a posterior lobe disposed at the posterior end of the bladder. Here, the posterior lobe may extend from a first end on a medial side of the bladder to a second end on a lateral side of the bladder. In some configurations plurality of lobes includes a lateral intermediate lobe and a medial intermediate lobe in direct fluid communication with the posterior lobe. Here, the lateral intermediate lobe and the medial intermediate lobe may be smaller than the posterior lobe. In some examples, a cross-sectional area of an interior void of the second chamber is greater at the intermediate portion of the posterior lobe than at the intermediate portions of each of the lateral intermediate lobe and the medial intermediate lobe. In some examples, a thickness of the intermediate portion of the posterior lobe defines a maximum thickness of the bladder. 
     In some implementations, the plurality of lobes includes a lateral intermediate lobe and a medial intermediate lobe disposed between the anterior end and the posterior end of the bladder. 
     In some examples, the first pressure is different than the second pressure. In some examples, the second pressure is greater than the first pressure. In some configurations, the first pressure ranges from 0 psi to 20 psi. In some implementations, the first pressure ranges from 5 psi to 15 psi. In some examples, the first pressure ranges from 7 psi to 10 psi. In some examples, the second pressure ranges from 0 psi to 35 psi. In some configurations, the second pressure ranges from 15 psi to 30 psi. In some implementations, the second pressure ranges from 20 psi to 25 psi. In some examples, the first pressure and the second pressure are atmospheric pressure. 
     In some configurations, a first thickness of the first chamber is greater than a second thickness of the second chamber at the anterior end and less than a third thickness of the second chamber at the posterior end. 
     Another aspect of the disclosure includes a sole structure including the bladder of any of the preceding clauses. 
     Another aspect of the disclosure is directed towards an article of footwear including the bladder described in the preceding paragraphs. 
     In another aspect of the disclosure, a sole structure is provided. The sole structure has a chassis including a bottom surface forming a first portion of the chassis and a recessed surface offset from the bottom surface to define a recess in a second portion of the chassis. The sole structure further includes a bladder disposed within the recess of the chassis and including a first chamber disposed in an interior region of the recess and a second chamber disposed in a peripheral region of the recess. The second chamber at least partially surrounds the first chamber and is fluidly isolated from the first chamber. 
     Implementations of the disclosure may include one or more of the following optional features. 
     In some examples, the second chamber completely surrounds the first chamber. 
     In some implementations, the second chamber partially surrounds the first chamber. 
     In some configurations, the first chamber has a different pressure than the second chamber. 
     In some examples, the chassis includes a cushioning element forming the bottom surface and the interior region of the recesses surface, and a cradle at least partially defining the peripheral region of the recessed surface, the cradle being formed of a different material than the cushioning element. 
     In some configurations, the recessed surface includes a plurality of supports each configured to interface with a respective lobe of the bladder. Here, a first one of the supports may be formed of a first material and a second one of the supports may be formed of a second material that is different than the first material. Optionally, the plurality of supports includes an interior support interfacing with the first chamber and a plurality of peripheral supports each interfacing with a respective lobe of the second chamber. 
     In some examples, the sole structure includes an outsole having a first portion attached to the chassis and a second portion attached to the bladder. Here, the second portion of the outsole optionally includes an interior portion attached to the first chamber and a peripheral portion attached to the second chamber and independently movable relative to the interior portion. 
     Referring to  FIGS.  1 - 6   , an article of footwear  10  includes a sole structure  100  and an upper  200  attached to the sole structure  100 . The article of footwear  10  may be divided into one or more regions. The regions may include a forefoot region  12 , a mid-foot region  14 , and a heel region  16 . The mid-foot region  14  may correspond with an arch area of the foot, and the heel region  16  may correspond with rear portions of the foot, including a calcaneus bone. The footwear  10  may further include an anterior end  18  associated with a forward-most point of the forefoot region  12 , and a posterior end  20  corresponding to a rearward-most point of the heel region  16 . A longitudinal axis A 10  of the footwear  10  extends along a length of the footwear  10  from the anterior end  18  to the posterior end  20 , and generally divides the footwear  10  into a lateral side  22  and a medial side  24 , as shown in  FIG.  3   . Accordingly, the lateral side  22  and the medial side  24  respectively correspond with opposite sides of the footwear  10  and extend through the regions  12 ,  14 ,  16 . 
     The article of footwear  10 , and more particularly, the sole structure  100 , may be further described as including an interior region  26  and a peripheral region  28 , as indicated in  FIG.  3   . The peripheral region  28  is generally described as being a region between the interior region  26  and an outer perimeter of the sole structure  100 . Particularly, the peripheral region  28  extends from the forefoot region  12  to the heel region  16  along each of the lateral side  22  and the medial side  24 , and wraps around each of the forefoot region  12  and the heel region  16 . Thus, the interior region  26  is circumscribed by the peripheral region  28 , and extends from the forefoot region  12  to the heel region  16  along a central portion of the sole structure  100 . 
     With reference to  FIG.  2   , the sole structure  100  includes a midsole  102  configured to provide cushioning characteristics to the sole structure  100 , and an outsole  104  configured to provide a ground-engaging surface  30  of the article of footwear  10 . Unlike conventional sole structures, the midsole  102  of the sole structure  100  may be formed compositely and include a plurality of subcomponents for providing desired forms of cushioning and support throughout the sole structure  100 . For example, the midsole  102  includes a bladder  106  and a chassis  108 , where the chassis  108  is attached to the upper  200  and provides an interface between the upper  200 , the bladder  106 , and the outsole  104 . 
     With reference to  FIGS.  7  and  8   , the bladder  106  of the midsole  102  may be described as extending along a longitudinal axis A 106  from a first, anterior end  112  to a second, posterior end  114  disposed at an opposite end of the bladder  106  than the anterior end  112 . When incorporated into the article of footwear  10 , the anterior end  112  of the bladder  106  is disposed within the heel region  16  or the midfoot region  14  and faces the anterior end  18  of the footwear  10 , while the posterior end  114  is disposed at the posterior end  20  of the footwear  10 . The bladder  106  may be further described as including an intermediate region  116  disposed between the anterior end  112  and the posterior end  114 . The geometry and features of the bladder  106  may also be described relative to the peripheral region  28  and the interior region  26  of the article of footwear  10 . 
     As shown in the cross-sectional views of  FIGS.  4 - 6   , the bladder  106  may be formed by an opposing pair of barrier layers  118 ,  120 , which can be joined to each other at discrete locations to define an overall shape of the bladder  106 . Alternatively, the bladder  106  can be produced from any suitable combination of one or more barrier layers. 
     As used herein, the term “barrier layer” (e.g., barrier layers  118 ,  120 ) encompasses both monolayer and multilayer films. In some embodiments, one or both of the barrier layers  118 ,  120  are each produced (e.g., thermoformed or blow molded) from a monolayer film (a single layer). In other embodiments, one or both of the barrier layers  118 ,  120  are each produced (e.g., thermoformed or blow molded) from a multilayer film (multiple sublayers). In either aspect, each layer or sublayer can have a film thickness ranging from about 0.2 micrometers to about be about 1 millimeter. In further embodiments, the film thickness for each layer or sublayer can range from about 0.5 micrometers to about 500 micrometers. In yet further embodiments, the film thickness for each layer or sublayer can range from about 1 micrometer to about 100 micrometers. 
     One or both of the barrier layers  118 ,  120  can independently be transparent, translucent, and/or opaque. As used herein, the term “transparent” for a barrier layer and/or a fluid-filled chamber means that light passes through the barrier layer in substantially straight lines and a viewer can see through the barrier layer. In comparison, for an opaque barrier layer, light does not pass through the barrier layer and one cannot see clearly through the barrier layer at all. A translucent barrier layer falls between a transparent barrier layer and an opaque barrier layer, in that light passes through a translucent layer but some of the light is scattered so that a viewer cannot see clearly through the layer. 
     The barrier layers  118 ,  120  can each be produced from an elastomeric material that includes one or more thermoplastic polymers and/or one or more cross-linkable polymers. In an aspect, the elastomeric material can include one or more thermoplastic elastomeric materials, such as one or more thermoplastic polyurethane (TPU) copolymers, one or more ethylene-vinyl alcohol (EVOH) copolymers, and the like. 
     As used herein, “polyurethane” refers to a copolymer (including oligomers) that contains a urethane group (—N(C═O)O—). These polyurethanes can contain additional groups such as ester, ether, urea, allophanate, biuret, carbodiimide, oxazolidinyl, isocynaurate, uretdione, carbonate, and the like, in addition to urethane groups. In an aspect, one or more of the polyurethanes can be produced by polymerizing one or more isocyanates with one or more polyols to produce copolymer chains having (—N(C═O)O—) linkages. 
     Examples of suitable isocyanates for producing the polyurethane copolymer chains include diisocyanates, such as aromatic diisocyanates, aliphatic diisocyanates, and combinations thereof. Examples of suitable aromatic diisocyanates include toluene diisocyanate (TDI), TDI adducts with trimethyloylpropane (TMP), methylene diphenyl diisocyanate (MDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), hydrogenated xylene diisocyanate (HXDI), naphthalene 1,5-diisocyanate (NDI), 1,5-tetrahydronaphthalene diisocyanate, para-phenylene diisocyanate (PPDI), 3,3′-dimethyldiphenyl-4, 4′-diisocyanate (DDDI), 4,4′-dibenzyl diisocyanate (DBDI), 4-chloro-1,3-phenylene diisocyanate, and combinations thereof. In some embodiments, the copolymer chains are substantially free of aromatic groups. 
     In particular aspects, the polyurethane polymer chains are produced from diisocynates including HMDI, TDI, MDI, H12 aliphatics, and combinations thereof. In an aspect, the thermoplastic TPU can include polyester-based TPU, polyether-based TPU, polycaprolactone-based TPU, polycarbonate-based TPU, polysiloxane-based TPU, or combinations thereof. 
     In another aspect, the polymeric layer can be formed of one or more of the following: EVOH copolymers, poly(vinyl chloride), polyvinylidene polymers and copolymers (e.g., polyvinylidene chloride), polyamides (e.g., amorphous polyamides), amide-based copolymers, acrylonitrile polymers (e.g., acrylonitrile-methyl acrylate copolymers), polyethylene terephthalate, polyether imides, polyacrylic imides, and other polymeric materials known to have relatively low gas transmission rates. Blends of these materials, as well as with the TPU copolymers described herein and optionally including combinations of polyimides and crystalline polymers, are also suitable. 
     The barrier layers  118 ,  120  may include two or more sublayers (multilayer film) such as shown in Mitchell et al., U.S. Pat. No. 5,713,141 and Mitchell et al., U.S. Pat. No. 5,952,065, the disclosures of which are incorporated by reference in their entireties. In embodiments where the barrier layers  118 ,  120  include two or more sublayers, examples of suitable multilayer films include microlayer films, such as those disclosed in Bonk et al., U.S. Pat. No. 6,582,786, which is incorporated by reference in its entirety. In further embodiments, the barrier layers  118 ,  120  may each independently include alternating sublayers of one or more TPU copolymer materials and one or more EVOH copolymer materials, where the total number of sublayers in each of the barrier layers  118 ,  120  includes at least four (4) sublayers, at least ten (10) sublayers, at least twenty (20) sublayers, at least forty (40) sublayers, and/or at least sixty (60) sublayers. 
     The bladder  106  can be produced from the barrier layers  118 ,  120  using any suitable technique, such as thermoforming (e.g. vacuum thermoforming), blow molding, extrusion, injection molding, vacuum molding, rotary molding, transfer molding, pressure forming, heat sealing, casting, low-pressure casting, spin casting, reaction injection molding, radio frequency (RF) welding, and the like. In an aspect, the barrier layers  118 ,  120  can be produced by co-extrusion followed by vacuum thermoforming to form the profile of the bladder  106 , which can optionally include one or more valves  121  (e.g., one way valves) that allows the bladder  106  to be filled with the fluid (e.g., gas). 
     The bladder  106  desirably has a low gas transmission rate to preserve its retained gas pressure. In some embodiments, the bladder  106  has a gas transmission rate for nitrogen gas that is at least about ten (10) times lower than a nitrogen gas transmission rate for a butyl rubber layer of substantially the same dimensions. In an aspect, bladder  106  has a nitrogen gas transmission rate of 15 cubic-centimeter/square-meter·atmosphere·day (cm 3 /m 2 ·atm·day) or less for an average film thickness of 500 micrometers (based on thicknesses of barrier layers  118 ,  120 ). In further aspects, the transmission rate is 10 cm 3 /m 2 ·atm·day or less, 5 cm 3 /m 2 ·atm·day or less, or 1 cm 3 /m 2 ·atm·day or less. 
     In the shown embodiment, the barrier layers  118 ,  120  include a first, upper barrier layer  118  and a second, lower barrier layer  120 . Each of the barrier layers  118 ,  120  includes an interior surface  122 ,  124  and a respective exterior surface  126 ,  128  formed on an opposite side of the barrier layer  118 ,  120  from the interior surface  122 ,  124 . The exterior surface  126  of the upper barrier layer  118  defines an upper surface of the bladder  106  and the exterior surface  128  of the lower barrier layer  120  defines a lower surface of the bladder  106 . As discussed below, thicknesses of the bladder  106  are defined by distances from the exterior surface  126  of the upper barrier layer  118  to the exterior surface  128  of the lower barrier layer  120 , measured along a vertical direction (i.e., perpendicular to the ground surface). 
     In the illustrated example, the interior surfaces  122 ,  124  of the barrier layers  118 ,  120  are joined together at discrete locations to define a plurality of chambers  130 ,  132 . As shown in  FIGS.  4 - 6   , the interior surfaces  122 ,  124  of the upper and lower barrier layers  118 ,  120  are spaced apart from each other to define respective interior voids  134 ,  136  of each of the chambers  130 ,  132 , while the interior surfaces  122 ,  124  are joined or attached to each other to form a web area  138  and a peripheral seam  140  surrounding each of the chambers  130 ,  132 . 
     In the illustrated example, the bladder  106  includes a first, interior chamber  130  disposed in the interior region  26  of the bladder  106  and a second, peripheral chamber  132  surrounding the interior chamber  130 . The web area  138  surrounds the interior chamber  130  and separates the interior chamber  130  from the peripheral chamber  132  such that the interior voids  134 ,  136  of the interior chamber  130  and the peripheral chamber  132  are isolated from each other (i.e., fluid or media cannot transfer between the interior voids  134 ,  136 ). The peripheral seam  140  extends around the outer periphery of the peripheral chamber  132  and defines an outer peripheral profile of the bladder  106 . 
     As shown in  FIGS.  7  and  8   , the interior chamber  130  extends continuously along the longitudinal axis A 106  of the bladder from an anterior end  142  at the anterior end  112  of the bladder  106  to a posterior end  144  at the posterior end  114  of the bladder  106 . When incorporated within the article of footwear  10 , the interior chamber  130  is configured to support a central portion of the heel corresponding to the bottom of the calcaneus bone, while the peripheral chamber  132  provides a separate support structure that receives a portion of the heel therein. 
     A distance from the anterior end  142  to the posterior end  144  defines a length L 130  of the interior chamber  130 . The interior chamber  130  may be described as including an intermediate portion  146  disposed between the anterior end  142  and the posterior end  144 . The interior chamber  130  may be further defined by a lateral side  148  and a medial side  150  each extending along opposite sides of the interior chamber  130  from the anterior end  142  to the posterior end  144 , whereby a width W 130  of the interior chamber  130  is defined by a lateral distance (i.e., perpendicular to the longitudinal axis A 106 ) from the lateral side  148  to the medial side  150 . As provided above, thicknesses T 130  ( FIG.  4   ) of the interior chamber  130  are defined by the distance from the exterior surface  126  of the upper barrier layer  118  to the exterior surface  128  of the lower barrier layer  120  along the length L 130  and width W 130  of the interior chamber  130 . 
     Referring to  FIGS.  4 ,  7 , and  8   , the interior chamber  130  may be configured such that at least one of the width W 130  and the thickness T 130  tapers along a lengthwise direction of the longitudinal axis A 106  of the bladder  106 . Particularly, the interior chamber  130  may have a greater width W 130  and/or thickness T 130  in the intermediate portion  146  than at one or both of the ends  142 ,  144 . Accordingly, the cross-sectional area of the interior chamber  130  may also taper from the intermediate portion  146  to each of the ends  142 ,  144 . In the illustrated example, the interior chamber  130  is formed as an ovoid, whereby the exterior surfaces  126 ,  128  of the upper barrier layer  118  and the lower barrier layer  120  are both convex in shape and each of the sides  148 ,  150  extends along an arcuate path. However, in other examples, either or both of the barrier layers  118 ,  120  may have other geometries, and at least a portion of the interior chamber  130  may have a constant cross-sectional area. 
     With continued reference to  FIGS.  7  and  8   , the peripheral chamber  132  extends along the peripheral region  28  from the anterior end  112  to the posterior end  114  of the bladder  106 . As shown, the peripheral chamber  132  completely surrounds the interior chamber  130  such that the interior void  136  of the peripheral chamber  132  is interminable. As shown, an overall length L 106  and width W 106  of the bladder  106  are defined by the peripheral chamber  132 , and more particularly, by the peripheral seam  140 . 
     Referring now to  FIGS.  4 - 6   , the peripheral chamber  132  is formed with a variable cross-section, such that at least one of a width W 132  and a thickness T 132  of the peripheral chamber  132  changes along a length of the peripheral chamber  132 . Here, the width W 132  of the peripheral chamber is defined as a distance across the peripheral chamber  132  from the web area  138  to the peripheral seam  140 , while the thickness T 132  is defined by the distances between the exterior surfaces  126 ,  128  of the bladder  106 . 
     Referring to  FIGS.  7 A and  7 B , the peripheral chamber  132  may include a plurality of lobes  152   a - 152   e  each forming a portion of the peripheral chamber  132  having a variable cross-sectional area. For example, each of the lobes  152   a - 152   e  includes a first end  154   a - 154   e  having a first cross-sectional area, a second end  156   a - 156   e  having a second cross-sectional area, and an intermediate portion  158   a - 158   e  disposed between the first end  154   a - 154   e  and the second end  156   a - 156   e  and having a third cross-sectional area that is greater than the first cross-sectional area and the second cross-sectional area. Accordingly, each of the lobes  152   a - 152   e  tapers towards the respective first end  154   a - 154   e  and second end  156   a - 156   e  from the intermediate portion  158   a - 158   e . In some examples, both the width W 132  and the thickness T 132  of each of the lobes  152   a - 152   e  tapers from the intermediate portion  158   a - 158   e.    
     As shown in  FIG.  7 B , the variable cross section of the peripheral chamber  132  results in the overall width W 106  of the bladder  106  being variable from the anterior end  112  to the posterior end  114 . Particularly, the bladder  106  has a first width W 106-1  across the intermediate portions  158   a ,  158   b  of the anterior lobes  152   a ,  152   b  adjacent to the anterior end  112 , a second width W 106-2  across the second ends  156   a ,  156   b  of the anterior lobes  152   a ,  152   b  in the intermediate region  116 , and a third width W 106-3  across the intermediate portions  158   d ,  158   e  of the intermediate lobes  152   d ,  152   e  adjacent to the posterior end  114 . Here, the second width W 106-2  is less than the first width W 106-1  and the third width W 106-3 , while the third width W 106-3  is greater than the first width W 106-1  and the second width W 106-2 . 
     The illustrated example of the bladder  106  includes a plurality of the lobes  152   a - 152   e  arranged end-to-end in series around the interior chamber  130  such that the cross-sectional area of the peripheral chamber  132  alternates between larger and smaller sizes. As shown, the plurality of the lobes  152   a - 152   e  includes a first pair of anterior lobes  152   a ,  152   b  disposed at the anterior end  112  of the bladder  106 , a posterior lobe  152   c  disposed at the posterior end  114  of the bladder  106 , and a pair of intermediate lobes  152   d ,  152   e  disposed in the intermediate region  116  of the bladder  106 . 
     The anterior lobes  152   a ,  152   b  of the peripheral chamber  132  include a lateral peripheral lobe  152   a  disposed at the anterior end  112  on the lateral side  22  of the bladder  106 , and a medial peripheral lobe  152   b  disposed at the anterior end  112  on the medial side  24  of the bladder  106 . As shown, the first ends  154   a ,  154   b  of the anterior lobes  152   a ,  152   b  are connected to each other at the longitudinal axis A 106  of the bladder  106 . Each of the anterior lobes  152   a ,  152   b  extends from its respective first end  154   a ,  154   b  and around the anterior end  142  of the interior chamber  130  to its respective second end  156   a ,  156   b  in the intermediate region  116  of the bladder  106 . In the illustrated example, the anterior lobes  152   a ,  152   b  provide the peripheral chamber  132  with an increased width W 132  at the lateral and medial sides of the anterior end  112  such that the anterior lobes  152   a ,  152   b  form a pair of forward-protruding portions at opposite sides of the anterior end  112  of the bladder  106 . 
     With continued reference to  FIGS.  7  and  8   , the posterior lobe  152   c  is disposed at the posterior end  114  of the bladder  106  and the intermediate portion  158   c  of the posterior lobe  152   c  is centrally positioned along the longitudinal axis A 106  of the bladder  106 . In the illustrated example, the posterior lobe  152   c  extends around the posterior end  144  of the interior chamber  130  from a first end  154   a  on the lateral side  22  of the bladder  106  to a second end  156   c  on the medial side  24  of the bladder  106 . As discussed above, the intermediate portion  158   c  has a greater cross-sectional area than each of the ends  154   c ,  156   c.    
     The intermediate lobes  152   d ,  152   e  of the peripheral chamber  132  include a lateral intermediate lobe  152   d  disposed in the intermediate region  116  on the lateral side  22  of the bladder  106 , and a medial intermediate lobe  152   e  disposed in the intermediate region  116  on the medial side  24  of the bladder  106 . As shown, first ends  154   d ,  154   e  of the intermediate lobes  152   d ,  152   e  are connected to the second ends  156   a ,  156   b  of the lateral and medial anterior lobes  152   a ,  152   b , respectively. The second end  156   d  of the lateral intermediate lobe  152   d  is connected to the first end  154   c  of the posterior lobe  152   c  at the posterior end  114  of the bladder  106 . Likewise, the second end  156   e  of the medial intermediate lobe  152   e  is connected to the second end  156   c  of the posterior lobe  152   c  at the posterior end  114  of the bladder  106 . Similar to the anterior lobes  152   a ,  152   b  at the anterior end  112  and the posterior lobe  152   c  at the posterior end  114 , the intermediate lobes  152   d ,  152   e  provide the peripheral chamber  132  with protruding portions along the lateral and medial sides  22 ,  24  of the intermediate region  116  of the bladder  106 . 
     Referring now to  FIG.  1   , the thickness T 106  the bladder  106  generally increases along a direction from the anterior end  112  to the posterior end  114 . However, as discussed above, because the peripheral chamber  132  is formed with a variable cross section, the change in thickness is not constant T 106  and continuous along the length of the bladder  106 . Instead, the thickness of the bladder  106  incrementally increases along the length L 106  of the bladder  106 . For example, the bladder  106  has a first thickness T 106-1  at the anterior end  112  defined by the intermediate portions  158   a ,  158   b  of the anterior lobes  152   a ,  152   b , a second thickness T 106-2  in the intermediate region  116  defined by the intermediate portions  158   d ,  158   e  of the intermediate lobes  152   d ,  152   e , and a third thickness T 106-3  at the posterior end  114  defined by the intermediate portion  158   c  of the posterior lobe  152   c . Here, the second thickness T 106-2  is greater than the first thickness T 106-1  and less than the third thickness T 106-3 , such that an average thickness of the bladder  106  increases from the anterior end  112  to the posterior end  114 . Furthermore, as shown in the cross-sectional view of  FIG.  4   , the thickness of the bladder  106  also incrementally increases along the longitudinal axis A 106 . Accordingly, the bladder  106  has a thickness T 106-4  at the first ends  154   a ,  154   b  of the anterior lobes  152   a ,  152   b  that is less than the thickness T 130  of the interior chamber  130 , which is, in turn, less than the thickness T 106-3  at the posterior lobe  152   c.    
     The chambers  130 ,  132  can be provided in a fluid-filled (e.g., as provided in footwear  10 ) or in an unfilled state. The chambers  130 ,  132  can be filled to include any suitable fluid, such as a gas or liquid. In an aspect, the gas can include air, nitrogen (N 2 ), or any other suitable gas. The fluid provided to the chambers  130 ,  132  can result in the bladder  106  being pressurized. Alternatively, the fluid provided to the chambers  130 ,  132  can be at atmospheric pressure such that the chambers  130 ,  132  are not pressurized but, rather, simply contains a volume of fluid at atmospheric pressure. In other aspects, the chambers  130 ,  132  can alternatively include other compressible media, such as pellets, beads, ground recycled material, and the like (e.g., foamed beads and/or rubber beads). 
     In the illustrated example, the interior void  134  of the interior chamber  130  includes a first fluid at a first pressure and the interior void  136  of the peripheral chamber  132  includes a second fluid at a second pressure. As discussed above, the interior chamber  130  is isolated from the peripheral chamber  132  such that the first pressure and the second pressure may be independently maintained within the interior voids  134 ,  136 . The first pressure and the second pressure may be different from each other. For instance, the first pressure within the interior void  134  of the interior chamber  130  may be less than the second pressure within the interior void  136  of the peripheral chamber  132  when the bladder  106  is in an uncompressed (i.e., natural) state. In some examples, the first pressure ranges from 0 psi to 20 psi, and more particularly from 5 psi to 15 psi, and even more particularly from 7 psi to 10 psi. The second pressure may range from 0 psi to 35 psi, and more particularly from 15 psi to 30 psi, and even more particularly from 20 psi to 25 psi. 
     Providing the bladder  106  with an interior chamber  130  having a lower pressure than the surrounding peripheral chamber  132  allows the interior chamber  130  to provide a softer cushioning response to a point load applied by the central portion of the heel when sole structure  100  contacts a ground surface. Upon initial compression of the interior chamber  130 , the higher pressure of the peripheral chamber  130  provides secondary cushioning around a perimeter of the heel. Furthermore, the higher pressure of the peripheral chamber  132  provides the heel region with enhanced lateral (i.e., side-to-side, front-to-back) stability. Thus, the dual-chamber configuration of the bladder  106  advantageously provides both impact attenuation and stability. 
     With continued reference to  FIGS.  1 - 4   , the chassis  108  of the sole structure  100  extends continuously from the anterior end  18  to the posterior end  20 . The chassis  108  includes a top surface  160  defining a profile of a footbed of the article of footwear  10 . The chassis  108  further includes a bottom surface  162  and a recessed surface  164  formed on an opposite side of the chassis  108  than the top surface  160 . In the illustrated example, the bottom surface  162  extends from the anterior end  18  of the sole structure  100  and terminates at an intermediate portion of the chassis  108  in the midfoot region  14 . 
     The recessed surface  164  is spaced between the top surface  160  and the bottom surface  162 , and defines a recess  166  in the heel region  16  of the sole structure  100  that is configured to receive the bladder  106 . Thus, a depth or height of the recess  166  is defined by the offset distance between the bottom surface  162  and the recessed surface  164 . Here, the height of the recess  166  is configured such that when the bladder  106  is disposed within the recess  166 , the lower surface  128  of the bladder  106  and the bottom surface  162  of the chassis  108  will cooperate to form a bottom support surface of the midsole  102  that attaches to the outsole  104 . 
     As best shown in  FIG.  4   , the recessed surface  164  may include one or more supports  168  configured to interface with the bladder  106 . Particularly, the one or more supports  168 - 168   e  are configured as protruding portions of the recessed surface  164  that oppose the upper barrier layer  118  of the bladder  106 . Accordingly, compression forces applied to the top surface  160  of the chassis  108  in the heel region  16  are transferred to the bladder  108  as localized loads by the one or more supports  168 - 168   e . Thus, the chassis  108  is not in continuous contact with the upper barrier layer  118 , but instead contacts the upper barrier layer  118  at one or more discrete interfaces between a lower support surface  170  of each support  168 - 168   e  and the upper barrier layer  118 . For example, the lower support surfaces  170 - 170   e  of the supports  168 - 168   e  may be configured to contact the uppermost portions of the upper barrier layer  118 . 
     In the illustrated example, the one or more supports  168  includes an interior support  168 - 168   e  formed in the interior region  26  of the recessed surface  164  and configured to oppose the portion of the upper barrier layer  118  forming the interior chamber  130 . The chassis  108  further includes a plurality of peripheral supports  168   a - 168   e  each configured to interface with a respective one of the lobes  152   a - 152   e  of the peripheral chamber  132 . Thus, the chassis  108  is attached to the bladder  106  at the uppermost portions of the interior chamber  130  and each of the lobes  152   a - 152   e , while lower portions of the upper barrier layer  118  (i.e., adjacent to and including the web area  138 ) are spaced apart and detached from the chassis  108 . 
     Optionally, the chassis  108  may be formed as a unitary body or as a composite structure. For instance, in the illustrated example, the chassis  108  is formed as a composite, multi-part structure including a cushioning element  172  and a cradle  174 . The cushioning element  172  is formed as a first part and extends from the anterior end  18  to the posterior end  20 . The cushioning element  172  defines the top surface  160  and the bottom surface  162  of the chassis  108 . The cushioning element  172  further defines a portion of the recessed surface  164  in the interior region  26  of the chassis  108  such that the interior support  168  is included in the cushioning element  172 . 
     The cradle  174  may be formed as a second part and attached to the cushioning element  172 . Here, the cradle  174  extends around the peripheral region  28  of the chassis  108  in the midfoot and heel regions  14 ,  16 . A portion of the recessed surface  164  in the peripheral region  28  of the chassis  108  is defined by the cradle  174 . Particularly, the cradle  174  may include one or more of the peripheral supports  168   a - 168   e . In the illustrated example, the cradle  174  includes all of the peripheral supports  168   a - 168   e . Accordingly, the interior support  168  is formed by the cushioning element  172  and the peripheral supports  168   a - 168   e  are formed by the cradle  174 . 
     Referring to  FIG.  1   , the cradle  174  may further include a peripheral wall  176  that extends upwardly from the recessed surface and at least partially surrounds the upper  200  to provide lateral support around an outer periphery of the sole structure  100  and the upper  200 . Optionally, the peripheral wall  176  may have an undulated profile, such that a height H 176  of the peripheral wall  176  varies along the outer periphery of the upper  200 . In some examples, the peripheral wall  176  of the cradle  174  may cooperate with a peripheral wall  178  of the cushioning element  172  to provide lateral support around the upper  200 . 
     In examples where the chassis  108  is formed as a composite structure including the cushioning element  172  and the cradle  174 , the cushioning element  172  and the cradle  174  may be formed of materials having different properties. For example, the cushioning element  172  may include first materials configured to provide desired levels of cushioning and impact attenuation, while the cradle  174  is formed of one or more materials configured to impart a greater degree of stiffness to the heel region  16  of the chassis  108 . In some examples, the cushioning element  172  may be formed in part of a first foam material and the cradle may be formed in part of a second foam material having a greater stiffness and/or density than the first foam material. As such, the interior support  168  that is formed by the cushioning element  172  may have different properties than the peripheral supports  168   a - 168   e  that are formed by the cradle  174 . However, as provided above, the inclusion of the cradle  174  is optional, such that the entire chassis  108  may be formed as a unitary structure where all of the supports  168 - 168   e  are formed of the same material. 
     With continued reference to  FIG.  2   , the outsole  104  is configured to be attached to the midsole  102  to provide a durable ground-engaging surface  30  to the sole structure  100 . The outsole  104  includes a top surface  180  that attaches to the bottom support surface  128 ,  162  of the midsole  102 , and a bottom surface  182  formed on an opposite side of the outsole  104  than the top surface  180 . The outsole  104  may be described as including a first portion  184  attached to the bottom surface  162  of the chassis  108  and a second portion  186  attached to the lower surface  128  of the bladder  106 . As shown, the outsole  104  is formed as a unitary structure such that the first portion  184  and the second portion  186  are attached to each other and effectively connect the lower surface  128  of the bladder  106  and the bottom surface  162  of the chassis  108  along the bottom of the sole structure  100 . 
     With continued reference to  FIGS.  2  and  3   , the second portion  186  of the outsole  104  may include an interior portion  188  associated with the interior chamber  130  and a peripheral portion  190  associated with the peripheral chamber  132 . The interior portion  188  of the outsole  104  is attached to a portion of the lower barrier layer  120  forming the interior chamber  130  while the peripheral portion  190  is attached to a portion of the lower barrier layer  120  forming the peripheral chamber  132 . 
     In some examples, the interior portion  188  and the peripheral portion  190  are formed separately from each other such that peripheral portion  190  can move completely independently from the interior portion  188 . In this configuration, the interior portion  188  may be spaced apart and separated from the peripheral portion  190  such that the bladder  106  is exposed therebetween. Optionally, the second portion  186  of the outsole  104  may include a flexure  192  disposed between and connecting the interior portion  188  and the peripheral portion  190 . The flexure  192  is configured to allow the peripheral portion  190  to move relatively independently from the interior portion  188 . For example, the flexure  192  may be detached and spaced apart from the bladder  106 , and/or may be formed with different properties (e.g., stiffness, thickness) than the interior and peripheral portions  188 ,  190  to allow relative movement thereof. 
     With continued reference to  FIGS.  3 - 6   , the outsole  104  may be overmolded on the lower barrier layer  120  of the bladder  106  to correspond to the features of the bladder  106 . For example, the peripheral portion  190  of the outsole  104  may be formed with lobes  194   a - 194   e  corresponding to the lobes  152   a - 152   e  of the peripheral chamber  132 , while the interior portion  188  of the outsole  104  conforms to the shape of the interior chamber  130 . As shown in  FIG.  1   , overmolding the outsole  104  onto the lobes  152   a - 152   e  of the bladder  106  provides the outsole  104  and the sole structure  100  with a series of compressible contact points along the ground-engaging surface  30 . 
     The upper  200  is attached to the sole structure  100  and includes interior surfaces that define an interior void  202  configured to receive and secure a foot for support on sole structure  100 . The upper  200  may be formed from one or more materials that are stitched or adhesively bonded together to form the interior void  202 . Suitable materials of the upper may include, but are not limited to, mesh, textiles, foam, leather, and synthetic leather. The materials may be selected and located to impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort. 
     With particular reference to  FIGS.  9  and  10 B , an article of footwear  10   a  is provided and includes a sole structure  100   a  and the upper  200  attached to the sole structure  100   a . In view of the substantial similarity in structure and function of the components associated with the article of footwear  10  with respect to the article of footwear  10   a , like reference numerals are used hereinafter and in the drawings to identify like components while like reference numerals containing letter extensions are used to identify those components that have been modified. 
     In the illustrated example, the sole structure  100   a  includes a midsole  102   a  and an outsole  104   a  having similar characteristics and configurations as the midsole  102  and the outsole  104  described above. However, the midsole  102   a  of this example includes a bladder  106   a  having the interior chamber  130  and a peripheral chamber  132   a  that only partially surrounds the interior chamber  130 . For example, as shown in  FIG.  10   , the peripheral chamber  132   a  includes a first terminal end  196   a  and a second terminal end  196   b  disposed at the anterior end  112  of the bladder  106   a . As shown, the peripheral chamber  132   a  extends along the lateral side  148  of the interior chamber  130  from the first terminal end  196   a , around the posterior end  144  of the interior chamber  130  at the posterior end  114  of the bladder  106 , and along the medial side  150  of the interior chamber  130  to the second terminal end  196   b . Accordingly, the peripheral chamber  132   a  of the bladder  106   a  may be described as being a U-shaped or horseshoe-shaped structure. 
     With continued reference to  FIG.  10   , the terminal ends  196   a ,  196   b  of the peripheral chamber  132   a  are spaced apart from each other along the lateral direction at the anterior end  112 . Here, the web area  138   a  may extend between and connect the terminal ends  196   a ,  196   b  at the anterior end  112 . Optionally, the web area  138   a  may include a valve  121   a  that provides fluid communication with the interior chamber  130  and the peripheral chamber  132   a  during a manufacturing process of the bladder  106   a.    
     As discussed above with respect to the bladder  106 , the peripheral chamber  132   a  of the bladder  106   a  includes one or more of the lobes  152   f - 152   h . In the illustrated example, the peripheral chamber  132   a  includes a lateral anterior lobe  152   f  disposed at the first terminal end  196   a  on the lateral side  22  of the bladder  106   a , and a medial anterior lobe  152   g  disposed at the second terminal end  196   b  on the medial side  24  of the bladder  106   a . The peripheral chamber  132   a  further includes a posterior lobe  152   h  disposed at the posterior end  114  of the bladder  106   a . In this example, the posterior lobe  152   h  may extend from a first end  154   h  that is connected to a second end  156   f  of the lateral anterior lobe  152   f  in the intermediate region  116  of the bladder  106   a , to a second end  156   g  that is connected to a second end  156   g  of the medial anterior lobe  152   g  in the intermediate region  116  of the bladder  106   a.    
     As shown in  FIG.  10 B , the variable cross section of the peripheral chamber  132   a  results in the overall width W 106a  of W the bladder  106   a  being variable from the anterior end  112  to the posterior end  114 . Particularly, the bladder  106   a  has a first width W 106a-1  across the intermediate portions  158   f ,  158   g  of the anterior lobes  152   f ,  152   g  adjacent to the anterior end  112 , a second width W 106a-2  across the second ends  156   f ,  156   g  of the anterior lobes  152   f ,  152   g  in the intermediate region  116 , and a third width W 106a-3  across the posterior lobe  152   h  at the first and second ends  154   h ,  156   h . Here, the second width W 106a-2  is less than the first width W 106a-1  and the third width W 106a-3 , while the third width W 106a-3  is greater than the first width W 106a-1  and the second width W 106a-2 . 
     In the illustrated example, the interior void  134  of the interior chamber  130  includes a first fluid at a first pressure and the interior void  136   a  of the peripheral chamber  132   a  includes a second fluid at a second pressure. As discussed above, the interior chamber  130  is isolated from the peripheral chamber  132  such that the first pressure and the second pressure may be independently maintained within the interior voids  134 ,  136   a . The first pressure and the second pressure may be different from each other. For instance, the first pressure within the interior void  134  of the interior chamber  130  may be less than the second pressure within the interior void  136   a  of the peripheral chamber  132   a  when the bladder  106  is in an uncompressed (i.e., natural) state. In some examples, the first pressure ranges from 0 psi to 20 psi, and more particularly from 5 psi to 15 psi, and even more particularly from 7 psi to 10 psi. The second pressure may range from 0 psi to 35 psi, and more particularly from 15 psi to 30 psi, and even more particularly from 20 psi to 25 psi. 
     With particular reference to  FIGS.  11  and  12   , an article of footwear  10   b  is provided and includes a sole structure  100   b  and the upper  200  attached to the sole structure  100   b . In view of the substantial similarity in structure and function of the components associated with the article of footwear  10  with respect to the article of footwear  10   b , like reference numerals are used hereinafter and in the drawings to identify like components while like reference numerals containing letter extensions are used to identify those components that have been modified. 
     In the illustrated example, the sole structure  100   b  includes a midsole  102   b  and an outsole  104   b  having similar characteristics and configurations as the midsoles  102 ,  102   a  and the outsoles  104 ,  104   a  described above. Here, the bladder  106   b  is formed with the interior chamber  130  and a peripheral chamber  132   b , where the peripheral chamber  132   b  is interminable and includes an elongate posterior lobe  152   k  extending around the posterior end  114  of the bladder  106   b . Optionally, the peripheral chamber  132   b  may include a valve  121   a  that provides fluid communication with the interior chamber  130  and the peripheral chamber  132   b  during a manufacturing process of the bladder  106   a.    
     As shown, the peripheral chamber  132   b  of the bladder  106   b  includes a series of the lobes  152   i - 152   k  including a lateral anterior lobe  152   i  disposed at the anterior end  112  on the lateral side  22 , and a medial anterior lobe  152   j  disposed at the anterior end  112  on the medial side  24 . Here, the first ends  154   i ,  154   j  of the anterior lobes  152   i ,  152   j  are connected to each other along the longitudinal axis A 106b  of the bladder  106   b  and the second ends  156   i ,  156   j  of the anterior lobes  152  extend into the intermediate region  116  on the lateral and medial sides  148 ,  150  of the interior chamber  130 . 
     The posterior lobe  152   k  extends from a first end  154   k  connected to the second end  156   i  of the lateral anterior lobe  152   i  in the intermediate region  116  on the lateral side  22 , to a second end  156   k  connected to the second end  156   j  of the medial anterior lobe  152   j  in the intermediate region on the medial side  24 . Thus, the posterior lobe  152   k  extends continuously around the posterior end  114  from the lateral side  22  of the bladder  106   b  to the medial side  24  of the bladder  106   b . In the illustrated example, the intermediate portion  158   k  of the posterior lobe may include a substantially constant cross-sectional area from the first end  154   k  to the second end  156   k.    
     As shown in  FIG.  12 B , the variable cross section of the peripheral chamber  132   b  results in the overall width W 106b  of the bladder  106   b  being variable from the anterior end  112  to the posterior end  114 . Particularly, the bladder  106   b  has a first width W 106b-1  across the intermediate portions  158   i ,  158   j  of the anterior lobes  152   i ,  152   j  adjacent to the anterior end  112 , a second width W 106b-2  across the second ends  156   i ,  156   j  of the anterior lobes  152   i ,  152   j  in the intermediate region  116 , and a third width W 106b-3  across the intermediate portion  158   k  of the posterior lobe  152   k  adjacent to the first and second ends  154   k ,  156   k . Here, the second width W 106b-2  is less than the first width W 106b-1  and the third width W 106b-3 , while the third width W 106b-3  is greater than the first width W 106b-1  and the second width W 106b-2 . 
     In the illustrated example, the interior void  134  of the interior chamber  130  includes a first fluid at a first pressure and the interior void  136   b  of the peripheral chamber  132   b  includes a second fluid at a second pressure. As discussed above, the interior chamber  130  is isolated from the peripheral chamber  132   b  such that the first pressure and the second pressure may be independently maintained within the interior voids  134 ,  136   b . The first pressure and the second pressure may be different from each other. For instance, the first pressure within the interior void  134  of the interior chamber  130  may be less than the second pressure within the interior void  136   b  of the peripheral chamber  132   b  when the bladder  106   b  is in an uncompressed (i.e., natural) state. In some examples, the first pressure ranges from 0 psi to 20 psi, and more particularly from 5 psi to 15 psi, and even more particularly from 7 psi to 10 psi. The second pressure may range from 0 psi to 35 psi, and more particularly from 15 psi to 30 psi, and even more particularly from 20 psi to 25 psi. 
     The following Clauses provide exemplary configurations for an article of footwear, a bladder for an article of footwear, or a sole structure for an article of footwear described above. 
     Clause 1: A bladder for an article of footwear, the bladder extending from an anterior end to a posterior end and comprising: a first chamber disposed in an interior region of the bladder and including a first interior void having a first pressure; and a second chamber at least partially surrounding the first chamber and including a second interior void having a second pressure. 
     Clause 2: The bladder of Clause 1, wherein the bladder has a first width adjacent to the anterior end of the bladder, a second width adjacent to the posterior end of the bladder, and a third width in an intermediate portion that is less than the first width and the second width. 
     Clause 3: The bladder of Clause 1, wherein the first chamber is an ovoid. 
     Clause 4: The bladder of Clause 1, wherein the second chamber includes an anterior portion having a first cross-sectional area, a posterior portion having a second cross-sectional area, and an intermediate portion connecting the anterior portion and the posterior portion and having a third cross-sectional area. 
     Clause 5: The bladder of Clause 4, wherein the third cross-sectional area is less than the first cross-sectional area. 
     Clause 6: The bladder of Clause 4, wherein the third cross-sectional area is less than the second cross-sectional area. 
     Clause 7: The bladder of Clause 4, wherein the third cross-sectional area is less than the first cross-sectional area and the second cross-sectional area. 
     Clause 8: The bladder of Clause 1, wherein the bladder includes a web area disposed between and connecting the first chamber and the second chamber. 
     Clause 9: The bladder of Clause 1, wherein the bladder includes a first barrier layer and a second barrier layer joined together at discrete locations to define the first chamber and the second chamber. 
     Clause 10: The bladder of Clause 9, wherein at least one of the first barrier layer and the second barrier layer is transparent. 
     Clause 11: The bladder of Clause 9, wherein at least one of the first barrier layer and the second barrier layer is translucent. 
     Clause 12: The bladder of Clause 1, wherein the second chamber completely surrounds the first chamber. 
     Clause 13: The bladder of Clause 1, wherein the second chamber partially surrounds the first chamber. 
     Clause 14: The bladder of Clause 1, wherein the second chamber includes a plurality of lobes, each lobe having a first end, a second end, and an intermediate portion disposed between the first end and the second end and being larger than the first end and the second end. 
     Clause 15: The bladder of Clause 14, wherein each lobe tapers from the intermediate portion to the first end and the second end. 
     Clause 16: The bladder of Clause 14, wherein, for each lobe, a thickness of the intermediate portion is greater than thicknesses of the first end and the second end. 
     Clause 17: The bladder of Clause 14, wherein, for each lobe, a width of the intermediate portion is greater than widths of the first end and the second end. 
     Clause 18: The bladder of Clause 14, wherein, for each lobe, a cross-sectional area of the intermediate portion is greater than the cross-sectional areas of the first end and the second end. 
     Clause 19: The bladder of Clause 14, wherein the plurality of the lobes are arranged in series around the first chamber. 
     Clause 20: The bladder of Clause 14, wherein the plurality of lobes includes a medial anterior lobe and a lateral anterior lobe. 
     Clause 21: The bladder of Clause 20, wherein the medial anterior lobe and the lateral anterior lobe are in direct fluid communication with each other. 
     Clause 22: The bladder of Clause 14, wherein the plurality of lobes includes a posterior lobe disposed at the posterior end of the bladder. 
     Clause 23: The bladder of Clause 22, wherein the posterior lobe extends from a first end on a medial side of the bladder to a second end on a lateral side of the bladder. 
     Clause 24: The bladder of Clause 22, wherein the plurality of lobes includes a lateral intermediate lobe and a medial intermediate lobe in direct fluid communication with the posterior lobe. 
     Clause 25: The bladder of Clause 24, wherein the lateral intermediate lobe and the medial intermediate lobe are smaller than the posterior lobe. 
     Clause 26: The bladder of Clause 24, wherein a cross-sectional area of an interior void of the second chamber is greater at the intermediate portion of the posterior lobe than at the intermediate portions of each of the lateral intermediate lobe and the medial intermediate lobe. 
     Clause 27: The bladder of Clause 22, wherein a thickness of the intermediate portion of the posterior lobe defines a maximum thickness of the bladder. 
     Clause 28: The bladder of Clause 14, wherein the plurality of lobes includes a lateral intermediate lobe and a medial intermediate lobe disposed between the anterior end and the posterior end of the bladder. 
     Clause 29: The bladder of Clause 1, wherein the first pressure is different than the second pressure. 
     Clause 30: The bladder of Clause 1, wherein the second pressure is greater than the first pressure. 
     Clause 31: The bladder of Clause 1, wherein the first pressure ranges from 0 psi to 20 psi. 
     Clause 32: The bladder of Clause 1, wherein the first pressure ranges from 5 psi to 15 psi. 
     Clause 33: The bladder of Clause 1, wherein the first pressure ranges from 7 psi to 10 psi. 
     Clause 34: The bladder of Clause 1, wherein the second pressure ranges from 0 psi to 35 psi. 
     Clause 35: The bladder of Clause 1, wherein the second pressure ranges from 15 psi to 30 psi. 
     Clause 36: The bladder of Clause 1, wherein the second pressure ranges from 20 psi to 25 psi. 
     Clause 37: The bladder of Clause 1, wherein the first pressure and the second pressure are atmospheric pressure. 
     Clause 38: The bladder of Clause 1, wherein a first thickness of the first chamber is greater than a second thickness of the second chamber at the anterior end and less than a third thickness of the second chamber at the posterior end. 
     Clause 39: A sole structure including the bladder of any of the preceding clauses. 
     Clause 40: An article of footwear including the bladder of any of Clause 1-37. 
     Clause 41: A sole structure for an article of footwear, the sole structure comprising: a chassis including a bottom surface forming a first portion of the chassis and a recessed surface offset from the bottom surface to define a recess in a second portion of the chassis; and a bladder disposed within the recess of the chassis and including a first chamber disposed in an interior region of the recess and a second chamber disposed in a peripheral region of the recess, the second chamber at least partially surrounding the first chamber and being fluidly isolated from the first chamber. 
     Clause 42: The sole structure of Clause 41, wherein the second chamber completely surrounds the first chamber. 
     Clause 43: The sole structure of Clause 41, wherein the second chamber partially surrounds the first chamber. 
     Clause 44: The sole structure of Clause 41, wherein the first chamber has a different pressure than the second chamber. 
     Clause 45: The sole structure of Clause 41, wherein the chassis includes a cushioning element forming the bottom surface and the interior region of the recesses surface, and a cradle at least partially defining the peripheral region of the recessed surface, the cradle being formed of a different material than the cushioning element. 
     Clause 46: The sole structure of Clause 41, wherein the recessed surface includes a plurality of supports each configured to interface with a respective lobe of the bladder. 
     Clause 47: The sole structure of Clause 46, wherein a first one of the supports is formed of a first material and a second one of the supports is formed of a second material that is different than the first material. 
     Clause 48: The sole structure of Clause 46, wherein the plurality of supports includes an interior support interfacing with the first chamber and a plurality of peripheral supports each interfacing with a respective lobe of the second chamber. 
     Clause 49: The sole structure of Clause 41, further comprising an outsole having a first portion attached to the chassis and a second portion attached to the bladder. 
     Clause 50: The sole structure of Clause 49, wherein the second portion of the outsole includes an interior portion attached to the first chamber and a peripheral portion attached to the second chamber and independently movable relative to the interior portion. 
     The foregoing description has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but, where applicable, are interchangeable and can be used in a selected configuration, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.