Patent Publication Number: US-11039662-B2

Title: Tethered fluid-filled chamber with multiple tether configurations

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is continuation of U.S. application Ser. No. 15/714,255, filed on Sep. 25, 2017, which is a continuation of U.S. patent application Ser. No. 14/718,449, filed on May 21, 2015, now U.S. Pat. No. 9,801,428, which is a continuation-in-part of U.S. application Ser. No. 13/563,458, filed Jul. 31, 2012, now U.S. Pat. No. 9,271,544, which is a divisional of U.S. application Ser. No. 12/630,642, filed Dec. 3, 2009, now U.S. Pat. No. 8,479,412, and claims the benefit of each of the aforementioned applications which are incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present teachings generally include an article comprising a chamber including a barrier forming a fluid-filled cavity with tethers connecting portions of the barrier. 
     BACKGROUND 
     Articles of footwear generally include two primary elements, an upper and a sole structure. The upper is formed from a variety of material elements (e.g., textiles, foam, leather, and synthetic leather) that are stitched or adhesively bonded together to form a void on the interior of the footwear for comfortably and securely receiving a foot. More particularly, the upper generally extends over the instep and toe areas of the foot, along the medial and lateral sides of the foot, under the foot, and around the heel area of the foot. In some articles of footwear, such as basketball footwear and boots, the upper may extend upward and around the ankle to provide support or protection for the ankle. Access to the void on the interior of the upper is generally provided by an ankle opening in a heel region of the footwear. A lacing system is often incorporated into the upper to adjust the fit of the upper, thereby permitting entry and removal of the foot from the void within the upper. The lacing system also permits the wearer to modify certain dimensions of the upper, particularly girth, to accommodate feet with varying dimensions. In addition, the upper may include a tongue that extends under the lacing system to enhance adjustability of the footwear. 
     The sole structure is located adjacent to a lower portion of the upper and is generally positioned between the foot and the ground. In many articles of footwear, including athletic footwear, the sole structure conventionally incorporates an insole, a midsole, and an outsole. The insole is a thin compressible member located within the void and adjacent to a lower surface of the void to enhance footwear comfort. The midsole, which may be secured to a lower surface of the upper and extends downward from the upper, forms a middle layer of the sole structure. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), the midsole may limit foot motions or impart stability, for example. The outsole, which may be secured to a lower surface of the midsole, forms the ground-contacting portion of the footwear and is usually fashioned from a durable and wear-resistant material that includes texturing to improve traction. 
     The conventional midsole is primarily formed from a foamed polymer material, such as polyurethane or ethylvinylacetate, that extends throughout a length and width of the footwear. In some articles of footwear, the midsole may include a variety of additional footwear elements that enhance the comfort or performance of the footwear, including plates, moderators, fluid-filled chambers, lasting elements, or motion control members. In some configurations, any of these additional footwear elements may be located between the midsole and either of the upper and outsole, embedded within the midsole, or encapsulated by the foamed polymer material of the midsole, for example. Although many conventional midsoles are primarily formed from a foamed polymer material, fluid-filled chambers or other non-foam structures may form a majority of some midsole configurations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a lateral side elevational view of an article of footwear. 
         FIG. 2  is a medial side elevational view of the article of footwear. 
         FIG. 3  is a cross-sectional view of the article of footwear, as defined by section line  3 - 3  in  FIG. 2 . 
         FIG. 4  is a perspective view of a first chamber from the article of footwear. 
         FIG. 5  is an exploded perspective view of the first chamber. 
         FIG. 6  is a side elevational view of the first chamber. 
         FIG. 7  is an exploded side elevational view of the first chamber. 
         FIGS. 8A and 8B  are cross-sectional views of the first chamber, as defined by section lines  8 A and  8 B in  FIG. 4 . 
         FIGS. 9A-9D  are partial cross-sectional views corresponding with an enlarged area in  FIG. 8A  and depicting further configurations of the first chamber. 
         FIGS. 10A and 10B  are cross-sectional views corresponding with  FIG. 8B  and depicting a force acting upon the first chamber. 
         FIGS. 11A-11C  are perspective views depicting further configurations of the first chamber. 
         FIGS. 12A-12N  are cross-sectional views corresponding with  FIG. 8B  and depicting further configurations of the first chamber. 
         FIG. 13  is a perspective view of a second chamber. 
         FIG. 14  is an exploded perspective view of the second chamber. 
         FIG. 15  is a side elevational view of the second chamber. 
         FIG. 16  is an exploded side elevational view of the second chamber. 
         FIGS. 17A and 17B  are cross-sectional views of the second chamber, as defined by section lines  17 A and  17 B in  FIG. 13 . 
         FIGS. 18A-18D  are cross-sectional views corresponding with  FIG. 17A  and depicting further configurations of the second chamber. 
         FIG. 19  is a perspective view of a third chamber. 
         FIG. 20  is an exploded perspective view of the third chamber. 
         FIG. 21  is a side elevational view of the third chamber. 
         FIG. 22  is an exploded side elevational view of the third chamber. 
         FIGS. 23A and 23B  are cross-sectional views of the third chamber, as defined by section lines  23 A and  23 B in  FIG. 19 . 
         FIGS. 24A-24D  are cross-sectional views corresponding with  FIG. 23A  and depicting further configurations of the third chamber. 
         FIG. 25  is a perspective view of a fourth chamber. 
         FIG. 26  is an exploded perspective view of the fourth chamber. 
         FIG. 27  is a side elevational view of the fourth chamber. 
         FIG. 28  is an exploded side elevational view of the fourth chamber. 
         FIGS. 29A and 29B  are cross-sectional views of the fourth chamber, as defined by section lines  29 A and  29 B in  FIG. 25 . 
         FIGS. 30A-30C  are cross-sectional views corresponding with  FIG. 29A  and depicting further configurations of the fourth chamber. 
         FIG. 31  is a schematic illustration in bottom view of a fifth chamber. 
         FIG. 32  is a schematic cross-sectional illustration of the fifth chamber taken at lines  32 - 32  in  FIG. 31 . 
         FIG. 33  is a schematic cross-sectional illustration of the fifth chamber taken at lines  33 - 33  in  FIG. 32 . 
         FIG. 34  is a schematic illustration in bottom view of a sixth chamber. 
         FIG. 35  is a schematic cross-sectional illustration of the sixth chamber taken at lines  35 - 35  in  FIG. 34 . 
         FIG. 36  is a schematic illustration in bottom view of a seventh chamber. 
         FIG. 37  is a schematic illustration in bottom view of an eighth chamber. 
     
    
    
     DESCRIPTION 
     An article comprises a chamber that includes a barrier formed from a polymer material. The barrier has a first portion that forms a first surface of the chamber, and a second portion that forms an opposite second surface of the chamber. The barrier forms at least one interior cavity between the first portion and the second portion. The barrier retains fluid in the at least one interior cavity. 
     The chamber includes a plurality of first tethers having a first configuration in the at least one interior cavity. The plurality of first tethers operatively connect the first portion to the second portion at a first area of the chamber. The chamber also has a plurality of second tethers having a second configuration in the at least one interior cavity. The plurality of second tethers operatively connect the first portion to the second portion at a second area of the chamber. The first configuration of the first plurality of tethers imparts a first compression characteristic to the chamber at the first area, and the second configuration of the second plurality of tethers imparts a second compression characteristic to the chamber at the second area. The second compression characteristic is different than the first compression characteristic. 
     The first and second compression characteristics can be imparted due to a variety of configurations of the tethers. For example, in an embodiment, the first configuration of the first plurality of tethers includes a first density and the second configuration of the second plurality of tethers includes a second density different than the first density. In the same or a different embodiment, the first configuration includes a first material, and the second configuration includes a second material different than the first material. In the same or a different embodiment, the first configuration includes a first length, and the second configuration includes a second length different than the first length. 
     In an embodiment, the chamber comprises a first polymer sheet including the first portion of the barrier and a second polymer sheet including the second portion of the barrier. The first polymer sheet and the second polymer sheet are bonded to one another so that the at least one interior cavity includes a first interior cavity and a second interior cavity. The plurality of first tethers is in the first interior cavity and the plurality of second tethers is in the second interior cavity. For example, the article may be an article of footwear having a heel region, a midfoot region, and a forefoot region. The first interior cavity may be in one of the heel region, the midfoot region, and the forefoot region, and the second interior cavity may be in any other one of the heel region, the midfoot region, and the forefoot region. 
     In an embodiment, the article is an article of footwear having a heel region, a midfoot region, and a forefoot region. The chamber comprises a first polymer sheet including the first portion of the barrier and a second polymer sheet including the second portion of the barrier. The first polymer sheet and the second polymer sheet are bonded to one another so that the at least one interior cavity includes a first interior cavity and a second interior cavity. The first interior cavity is in each of the heel region, the midfoot region, and the forefoot region, and the second interior cavity is in at least one of the heel region, the midfoot region, and the forefoot region. The plurality of first tethers is in the first interior cavity and the plurality of second tethers is in the second interior cavity. 
     In various embodiments, the second area borders the first area, and the second area may at least partially surround the first area. For example, the article may be an article of footwear having a heel region, a midfoot region, and a forefoot region. The chamber may comprise a first polymer sheet including the first portion of the barrier and a second polymer sheet including the second portion of the barrier. The first polymer sheet and the second polymer sheet may be bonded to one another so that the at least one interior cavity includes a first interior cavity and a second interior cavity. The first interior cavity may be in at least one of the heel region, the midfoot region, and the forefoot region, and the second interior cavity may be in at least one of the heel region, the midfoot region, and the forefoot region. The plurality of first tethers and the plurality of second tethers may both be in the first interior cavity or may both be in the second interior cavity. In another example embodiment, the first interior cavity is in each of the heel region, the midfoot region, and the forefoot region, the second interior cavity is in any one of the heel region, the midfoot region, and the forefoot region, and the plurality of first tethers and the plurality of second tethers are both in the first interior cavity or are both in the second interior cavity. 
     In an embodiment, the chamber includes a first plate secured to an inner surface of the first portion, and a second plate secured to an inner surface of the second portion. The plurality of first tethers is joined to the first plate and to the second plate. The plurality of second tethers may also be joined to the first plate and to the second plate, or, in an embodiment in which the chamber further includes a third plate secured to the inner surface of the first portion, and a fourth plate secured to the inner surface of the second portion, the plurality of second tethers may be joined to the third plate and to the fourth plate. 
     An article may comprise a chamber including a barrier formed from a first polymer sheet and a second polymer sheet bonded to one another to form a first interior cavity and a second interior cavity. The first and second interior cavities are filled with fluid retained by the barrier. A first tether element is in the first interior cavity and operatively connects the first polymer sheet to the second polymer sheet. A second tether element is in the second interior cavity and also operatively connects the first polymer sheet to the second polymer sheet. 
     In an embodiment, the first tether element includes a first plate secured to an inner surface of the first polymer sheet, a second plate secured to an inner surface of the second polymer sheet, a plurality of first tethers joined to the first plate and to the second plate and extending between the first plate and the second plate in the first interior cavity, and the second tether element includes a third plate secured to the inner surface of the first polymer sheet, a fourth plate secured to the inner surface of the second polymer sheet, and a plurality of second tethers joined to the third plate and the fourth plate and extending between the third plate and the fourth plate in the second interior cavity. The plurality of first tethers may have a first configuration that imparts a first compression characteristic to the chamber at the first tether element, and the plurality of second tethers may have a second configuration that imparts a second compression characteristic different than the first compression characteristic to the chamber at the second tether element. 
     In another embodiment, the first tether element includes a plurality of first tethers having a first configuration operatively connecting the first portion to the second portion at a first area of the chamber, a plurality of second tethers having a second configuration operatively connecting the first portion to the second portion at a second area of the chamber. The first configuration may impart a first compression characteristic to the chamber at the first area, and the second configuration may impart a second compression characteristic different than the first compression characteristic to the chamber at the second area. In such an embodiment, the second area may border and at least partially surround the first area. Furthermore, the article may be an article of footwear having a heel region, a midfoot region, and a forefoot region, and the first interior cavity may be in at least one different one of the heel region, the midfoot region, and the forefoot region than the second interior cavity. 
     The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the modes for carrying out the present teachings when taken in connection with the accompanying drawings. 
     “A,” “an,” “the,” “at least one,” and “one or more” are used interchangeably to indicate that at least one of the items is present. A plurality of such items may be present unless the context clearly indicates otherwise. All numerical values of parameters (e.g., of quantities or conditions) in this specification, unless otherwise indicated expressly or clearly in view of the context, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. In addition, a disclosure of a range is to be understood as specifically disclosing all values and further divided ranges within the range. 
     The terms “comprising,” “including,” and “having” are inclusive and therefore specify the presence of stated features, steps, operations, elements, or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, or components. Orders of steps, processes, and operations may be altered when possible, and additional or alternative steps may be employed. As used in this specification, the term “or” includes any one and all combinations of the associated listed items. The term “any of” is understood to include any possible combination of referenced items, including “any one of” the referenced items. The term “any of” is understood to include any possible combination of referenced claims of the appended claims, including “any one of” the referenced claims. 
     Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively relative to the figures, and do not represent limitations on the scope of the invention, as defined by the claims. 
     The following discussion and accompanying figures disclose an article of footwear, as well as various fluid-filled chambers that may be incorporated into the footwear. Concepts related to the chambers are disclosed with reference to footwear that is suitable for running. The chambers are not limited to footwear designed for running, however, and may be utilized with a wide range of athletic footwear styles, including basketball shoes, cross-training shoes, cycling shoes, football shoes, soccer shoes, tennis shoes, and walking shoes, for example. The chambers may also be utilized with footwear styles that are generally considered to be non-athletic, including dress shoes, loafers, sandals, and boots. The concepts disclosed herein may, therefore, apply to a wide variety of footwear styles, in addition to the specific style discussed in the following material and depicted in the accompanying figures. The chambers may also be utilized with a variety of other products, including backpack straps, mats for yoga, seat cushions, and protective apparel, for example. 
     General Footwear Structure 
     An article of footwear  10  is depicted in  FIGS. 1-3  as including an upper  20  and a sole structure  30 . For reference purposes, footwear  10  may be divided into three general regions: a forefoot region  11 , a midfoot region  12 , and a heel region  13 , as shown in  FIGS. 1 and 2 . Footwear  10  also includes a lateral side  14  and a medial side  15 . Forefoot region  11  generally includes portions of footwear  10  corresponding with the toes and the joints connecting the metatarsals with the phalanges. Midfoot region  12  generally includes portions of footwear  10  corresponding with the arch area of the foot, and heel region  13  corresponds with rear portions of the foot, including the calcaneus bone. Lateral side  14  and medial side  15  extend through each of regions  11 - 13  and correspond with opposite sides of footwear  10 . Regions  11 - 13  and sides  14 - 15  are not intended to demarcate precise areas of footwear  10 . Rather, regions  11 - 13  and sides  14 - 15  are intended to represent general areas of footwear  10  to aid in the following discussion. In addition to footwear  10 , regions  11 - 13  and sides  14 - 15  may also be applied to upper  20 , sole structure  30 , and individual elements thereof. 
     Upper  20  is depicted as having a substantially conventional configuration incorporating a plurality of material elements (e.g., textiles, foam, leather, and synthetic leather) that are stitched or adhesively bonded together to form an interior void for securely and comfortably receiving a foot. The material elements may be selected and located with respect to upper  20  in order to selectively impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. An ankle opening  21  in heel region  13  provides access to the interior void. In addition, upper  20  may include a lace  22  that is utilized in a conventional manner to modify the dimensions of the interior void, thereby securing the foot within the interior void and facilitating entry and removal of the foot from the interior void. Lace  22  may extend through apertures in upper  20 , and a tongue portion of upper  20  may extend between the interior void and lace  22 . Given that various aspects of the present discussion primarily relate to sole structure  30 , upper  20  may exhibit the general configuration discussed above or the general configuration of practically any other conventional or non-conventional upper. Accordingly, the structure of upper  20  may vary significantly within the scope of the present invention. 
     Sole structure  30  is secured to upper  20  and has a configuration that extends between upper  20  and the ground. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), sole structure  30  may provide traction, impart stability, and limit various foot motions, such as pronation. The primary elements of sole structure  30  are a midsole element  31 , an outsole  32 , and a chamber  33 . Midsole element  31  is secured to a lower area of upper  20  and may be formed from various polymer foam materials (e.g., polyurethane or ethylvinylacetate foam) that extend through each of regions  11 - 13  and between sides  14  and  15 . Additionally, midsole element  31  at least partially envelops or receives chamber  33 , which will be discussed in greater detail below. Outsole  32  is secured to a lower surface of midsole element  31  and may be formed from a textured, durable, and wear-resistant material (e.g., rubber) that forms the ground-contacting portion of footwear  10 . In addition to midsole element  31 , outsole  32 , and chamber  33 , sole structure  30  may incorporate one or more support members, moderators, or reinforcing structures, for example, that further enhance the ground reaction force attenuation characteristics of sole structure  30  or the performance properties of footwear  10 . Sole structure  30  may also incorporate a sockliner  34 , as depicted in  FIG. 3 , that is located within a lower portion of the void in upper  20  and is positioned to contact a plantar (i.e., lower) surface of the foot to enhance the comfort of footwear  10 . 
     When incorporated into sole structure  30 , chamber  33  has a shape that fits within a perimeter of midsole element  31  and extends through heel region  13 , extends into midfoot region  12 , and also extends from lateral side  14  to medial side  15 . Although chamber  33  is depicted as being exposed through the polymer foam material of midsole element  31 , chamber  33  may be entirely encapsulated within midsole element  31  in some configurations of footwear  10 . When the foot is located within upper  20 , chamber  33  extends under a heel area of the foot in order to attenuate ground reaction forces that are generated when sole structure  30  is compressed between the foot and the ground during various ambulatory activities, such as running and walking. In some configurations, chamber  33  may protrude outward from midsole element  31  or may extend further into midfoot region  12  and may also extend forward to forefoot region  11 . Accordingly, the shape and dimensions of chamber  33  may vary significantly to extend through various areas of footwear  10 . Moreover, any of a variety of other chambers  100 ,  200 , and  300  (disclosed in greater detail below) may be utilized in place of chamber  33  in footwear  10 . 
     First Chamber Configuration 
     The primary components of chamber  33 , which is depicted individually in  FIGS. 4-8B , are a barrier  40  and a tether element  50 . Barrier  40  forms an exterior of chamber  33  and (a) defines an interior cavity that receives both a pressurized fluid and tether element  50  and (b) provides a durable sealed barrier for retaining the pressurized fluid within chamber  33 . The polymer material of barrier  40  includes a first or upper barrier portion  41 , an opposite second or lower barrier portion  42 , and a sidewall barrier portion  43  that extends around a periphery of chamber  33  and between barrier portions  41  and  42 . Tether element  50  is located within the interior cavity and has a configuration that includes a first or upper plate  51 , an opposite second or lower plate  52 , and a plurality of tethers  53  that extend between plates  51  and  52 . Whereas upper plate  51  is secured to an inner surface of upper barrier portion  41 , lower plate  52  is secured to an inner surface of lower barrier portion  42 . Either adhesive bonding or thermobonding, for example, may be utilized to secure tether element  50  to barrier  40 . 
     In manufacturing chamber  33 , a pair of polymer sheets may be molded and bonded during a thermoforming process to define barrier portions  41 - 43 . More particularly, the thermoforming process (a) imparts shape to one of the polymer sheets in order to form upper barrier portion  41 , (b) imparts shape to the other of the polymer sheets in order to form lower barrier portion  42  and sidewall barrier portion  43 , and (c) forms a peripheral bond  44  that joins a periphery of the polymer sheets and extends around an upper area of sidewall barrier portion  43 . The thermoforming process may also locate tether element  50  within chamber  33  and bond tether element  50  to each of barrier portions  41  and  42 . Although substantially all of the thermoforming process may be performed with a mold, each of the various parts of the process may be performed separately in forming chamber  33 . Other processes that utilize blowmolding, rotational molding, or the bonding of polymer sheets without thermoforming may also be utilized to manufacture chamber  33 . 
     Following the thermoforming process, a fluid may be injected into the interior cavity and pressurized. The pressurized fluid exerts an outward force upon barrier  40  and plates  51  and  52 , which tends to separate barrier portions  41  and  42 . Tether element  50 , however, is secured to each of barrier portions  41  and  42  in order to retain the intended shape of chamber  33  when pressurized. More particularly, tethers  53  extend across the interior cavity and are placed in tension by the outward force of the pressurized fluid upon barrier  40 , thereby preventing barrier  40  from expanding outward and retaining the intended shape of chamber  33 . Whereas peripheral bond  44  joins the polymer sheets to form a seal that prevents the fluid from escaping, tether element  50  prevents chamber  33  from expanding outward or otherwise distending due to the pressure of the fluid. That is, tether element  50  effectively limits the expansion of chamber  33  to retain an intended shape of surfaces of barrier portions  41  and  42 . 
     The fluid within chamber  33  may be pressurized between zero and three-hundred-fifty kilopascals (i.e., approximately fifty-one pounds per square inch) or more. In addition to air and nitrogen, the fluid may include any of the gasses disclosed in U.S. Pat. No. 4,340,626 to Rudy, which is incorporated by reference in its entirety. In some configurations, chamber  33  may incorporate a valve or other structure that permits the wearer or another individual to adjust the pressure of the fluid. 
     A wide range of polymer materials may be utilized for barrier  40 . In selecting materials for barrier  40 , engineering properties of the material (e.g., tensile strength, stretch properties, fatigue characteristics, dynamic modulus, and loss tangent) as well as the ability of the material to prevent the diffusion of the fluid contained by barrier  40  may be considered. When formed of thermoplastic urethane, for example, barrier  40  may have a thickness of approximately 1.0 millimeter, but the thickness may range from 0.25 to 4.0 millimeters or more, for example. In addition to thermoplastic urethane, examples of polymer materials that may be suitable for barrier  40  include polyurethane, polyester, polyester polyurethane, and polyether polyurethane. Barrier  40  may also be formed from a material that includes alternating layers of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos. 5,713,141 and 5,952,065 to Mitchell, et al. which are incorporated by reference in their entireties. A variation upon this material may also be utilized, wherein a center layer is formed of ethylene-vinyl alcohol copolymer, layers adjacent to the center layer are formed of thermoplastic polyurethane, and outer layers are formed of a regrind material of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer. Another suitable material for barrier  40  is a flexible microlayer membrane that includes alternating layers of a gas barrier material and an elastomeric material, as disclosed in U.S. Pat. Nos. 6,082,025 and 6,127,026 to Bonk, et al., which are incorporated by reference in their entireties. Additional suitable materials are disclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy, which are incorporated by reference in their entireties. Further suitable materials include thermoplastic films containing a crystalline material, as disclosed in U.S. Pat. Nos. 4,936,029 and 5,042,176 to Rudy, which are incorporated by reference in their entireties, and polyurethane including a polyester polyol, as disclosed in U.S. Pat. Nos. 6,013,340; 6,203,868; and 6,321,465 to Bonk, et al., which are incorporated by reference in their entireties. 
     As discussed above, tether element  50  includes upper plate  51 , the opposite lower plate  52 , and the plurality of tethers  53  that extend between plates  51  and  52 . Each of plates  51  and  52  have a generally continuous and planar configuration. Tethers  53  are secured to each of plates  51  and  52  and space plates  51  and  52  apart from each other. More particularly, the outward force of the pressurized fluid places tethers  53  in tension and restrains further outward movement of plates  51  and  52  and barrier portions  41  and  42 . 
     Plates  51  and  52  impart a particular shape and contour to the upper and lower surfaces of chamber  33 . Given that plates  51  and  52  exhibit a planar configuration, the upper and lower surfaces of chamber  33  exhibit a corresponding planar configuration. As discussed in greater detail below, however, one or both of plates  51  and  52  may be contoured to impart a contoured configuration to surfaces of chamber  33 . Although plates  51  and  52  may extend across substantially all of the length and width of chamber  33 , plates  51  and  52  are depicted in  FIGS. 8A and 8B  as being spaced inward from sidewall barrier portion  43 . That is, plates  51  and  52  are depicted as only extending across a portion of the length and width of chamber  33 . In this configuration, upper plate  51  extends adjacent to at least fifty percent of upper barrier portion  41 , and lower plate  52  extends adjacent to at least fifty percent of lower barrier portion  42 . Without tether element  50 , chamber  33  would effectively bulge or otherwise distend to a generally rounded shape. Plates  51  and  52 , however, retain an intended shape in barrier portions  41  and  42 , and tethers  53  limit the degree to which plates  51  and  52  may separate. Given that areas where plates  51  and  52  are absent may bulge or distend outward, extending plates  51  and  52  adjacent to at least fifty percent of barrier portions  41  and  42  ensures that central areas of barrier portions  41  and  42  remain properly shaped. Although peripheral areas of barrier portions  41  and  42  may protrude outward due to the absence of plates  51  and  52 , forming chamber  33  such that plates  51  and  52  extend adjacent to at least fifty percent of barrier portions  41  and  42  ensures that chamber  33  remains suitably-shaped for use in footwear  10 . 
     A variety of structures may be utilized to secure tethers  53  to each of plates  51  and  52 . As depicted in an enlarged area of  FIG. 8A , for example, tethers  53  are merely secured to upper plate  51 , and a similar configuration may be utilized to join tethers  53  to lower plate  52 . A variety of securing structures may also be utilized. Referring to  FIG. 9A , ends of tethers  53  include enlarged areas that may assist with anchoring tethers  53  within upper plate  51 .  FIG. 9B  depicts a configuration wherein each of tethers  53  are secured to a restraint  54  located on an upper surface of upper plate  51  (i.e., between upper plate  51  and upper barrier portion  41 ). Each of restraints  54  may have the configuration of a disk that is joined to an end of one of tethers  53 . In another configuration, as depicted in  FIG. 9C , a single tether  53  extends through upper plate  51  in two locations and runs along the upper surface of upper plate  51 . The various tethers  53  may, therefore, be formed from a single strand or other element that repeatedly passes through plates  51  and  52 . As another example, individual tethers  53  may be secured to a lower surface of upper plate  51 , as depicted in  FIG. 9D , with an adhesive or thermobonding. Accordingly, tethers  51  may be secured to plates  51  and  52  in a variety of ways. 
     Plates  51  and  52  may be formed from a variety of materials, including various polymer materials, composite materials, and metals. More particularly, plates  51  and  52  may be formed from polyethylene, polypropylene, thermoplastic polyurethane, polyether block amide, nylon, and blends of these materials. Composite materials may also be formed by incorporating glass fibers or carbon fibers into the polymer materials discussed above in order to enhance the overall strength of tether element  50 . In some configurations of chamber  33 , plates  51  and  52  may also be formed from aluminum, titanium, or steel. Although plates  51  and  52  may be formed from the same materials (e.g., a composite of polyurethane and carbon fibers), plates  51  and  52  may be formed from different materials (e.g., a composite and aluminum, or polyurethane and polyethylene). As a related matter, the material forming barrier  40  generally has lesser stiffness than plates  51  and  52 . Whereas the foot may compress barrier  40  during walking, running, or other ambulatory activities, plates  51  and  52  may remain more rigid and less flexible when the material forming plates  51  and  52  generally has greater stiffness than the material forming barrier  40 . 
     Tethers  53  may be formed from any generally one-dimensional material. As utilized with respect to the present invention, the term “one-dimensional material” or variants thereof is intended to encompass generally elongate materials exhibiting a length that is substantially greater than a width and a thickness. Accordingly, suitable materials for tethers  53  include various strands, filaments, fibers, yarns, threads, cables, or ropes that are formed from rayon, nylon, polyester, polyacrylic, silk, cotton, carbon, glass, aramids (e.g., para-aramid fibers and meta-aramid fibers), ultra high molecular weight polyethylene, liquid crystal polymer, copper, aluminum, and steel. Whereas filaments have an indefinite length and may be utilized individually as tethers  53 , fibers have a relatively short length and generally go through spinning or twisting processes to produce a strand of suitable length. An individual filament utilized in tethers  53  may be formed form a single material (i.e., a monocomponent filament) or from multiple materials (i.e., a bicomponent filament). Similarly, different filaments may be formed from different materials. As an example, yarns utilized as tethers  53  may include filaments that are each formed from a common material, may include filaments that are each formed from two or more different materials, or may include filaments that are each formed from two or more different materials. Similar concepts also apply to threads, cables, or ropes. The thickness of tethers  53  may also vary significantly to range from 0.03 millimeters to more than 5 millimeters, for example. Although one-dimensional materials will often have a cross-section where width and thickness are substantially equal (e.g., a round or square cross-section), some one-dimensional materials may have a width that is greater than a thickness (e.g., a rectangular, oval, or otherwise elongate cross-section). Despite the greater width, a material may be considered one-dimensional if a length of the material is substantially greater than a width and a thickness of the material. 
     Tethers  53  are arranged in rows that extend longitudinally along the lengths of plate  51  and  52 . Referring to  FIG. 8B , nine tethers  53  extend across the width of chamber  33 , and each of the nine tethers are within one of the longitudinally-extending rows. Whereas the central row of tethers  53  is oriented to have a generally vertical orientation, the more peripheral rows of tethers  53  are oriented diagonally. That is, tethers  53  may be secured to offset areas of plates  51  and  52  in order to induce the diagonal orientation. An advantage of the diagonal orientation of tethers  53  relates to the stability of footwear  10 . Referring to  FIG. 10A , a force  16  is shown as compressing sole structure  30  and thrusting toward lateral side  14 , which may correspond to a cutting motion that is utilized in many athletic activities to move an individual side-to-side. When force  16  deforms chamber  33  in this manner, tethers  53  adjacent to medial side  15  are placed in tension due to their sloping or diagonal orientation, as represented by various arrows  17 . The tension in tethers  53  adjacent to medial side  15  resists the deformation of chamber  33 , thereby resisting the collapse of lateral side  14 . Similarly, referring to  FIG. 10B , force  16  is shown as compressing sole structure  30  and thrusting toward medial side  15 , which may also correspond to a cutting motion. When force  16  deforms chamber  33  in this manner, tethers  53  adjacent to lateral side  14  are placed in tension due to their sloping or diagonal orientation, as represented by the various arrows  17 . The tension in tethers  53  adjacent to lateral side  14  resists the deformation of chamber  33 , thereby resisting the collapse of medial side  15 . Accordingly, the diagonal orientation of tethers  53  resists deformation in chamber  33 , thereby enhancing the overall stability of footwear  10  during walking, running, or other ambulatory activities. 
     The overall shape of chamber  33  and the areas of footwear  10  in which chamber  33  is located may vary significantly. Referring to  FIG. 11A , chamber  33  has a generally round configuration that may be located solely within heel region  13 , for example. Another shape is depicted in  FIG. 11B , wherein chamber  33  has a configuration that extends through both heel region  13  and midfoot region  12 . In this configuration chamber  33  may replace midsole element  31  such that chamber  33  extends from lateral side  14  to medial side  15  and from upper  20  to outsole  32 . A similar configuration is depicted in  FIG. 11C , wherein chamber  33  has a shape that fits within a perimeter of sole structure  30  and extends under substantially all of the foot, thereby corresponding with a general outline of the foot. In this configuration chamber  33  may also replace midsole element  31  such that chamber  33  extends from lateral side  14  to medial side  15 , from heel region  13  to forefoot region  11 , and from upper  20  to outsole  32 . 
     Although the structure of chamber  33  discussed above and depicted in the figures provides a suitable example of a configuration that may be utilized in footwear  10 , a variety of other configurations may also be utilized. Referring to  FIG. 12A , chamber  33  exhibits a tapered configuration. One manner of imparting the tapered configuration relates to the relative lengths of tethers  53 . Whereas tethers  53  are relatively long in the areas of chamber  33  exhibiting greater thicknesses, tethers  53  are relatively short in the areas of chamber  33  exhibiting lesser thicknesses. By varying the lengths of tethers  53 , therefore, tapers or other features may be incorporated into chamber  33 . The taper in  FIG. 12A  extends from lateral side  14  to medial side  15 . A taper may also extend from heel region  13  to forefoot region  12 , as in the configuration of chamber  33  depicted in  FIG. 11C . Another configuration of chamber  33  is depicted in  FIG. 12B , wherein a central area of chamber  33  is depressed relative to the peripheral areas. More particularly, upper plate  51  is contoured to have a non-planar configuration, thereby forming a depression in the central area. When incorporated into footwear  10 , the depression may correspond with the location of the heel of the wearer, thereby providing an area for securely-receiving the heel. A similar depression is also formed in the configuration of chamber  33  depicted in  FIG. 11C . In other configurations, upper plate  51  may be contoured to form a protruding arch support area, for example. As a related matter, the relative lengths of tethers  53  vary throughout the configuration depicted in  FIG. 12B . More particularly, tethers  53  in the peripheral areas have greater lengths than tethers  53  in the central area. 
     Various aspects relating to tethers  53  may also vary. Referring to  FIG. 12C , each of tethers  53  exhibit a diagonal orientation. In some configurations, tethers  53  may cross each other to form x-shaped structures with opposing diagonal orientations, as depicted in  FIG. 12D . Additionally, the spacing between adjacent tethers  53  may vary significantly, as depicted in  FIG. 12E , and tethers  53  may be absent from some areas of chamber  33 . While tethers  53  may be formed from any generally one-dimensional material, a variety of other materials or structures may be located between plates  51  and  52  to prevent barrier  40  from expanding outward and retain the intended shape of chamber  33 . Referring to  FIG. 12F , for example, a variety of other tethers are located between plates  51  and  51 . More particularly, a fluid-filled member  55  and a foam member  56  are bonded to plates  51  and  52 , both of which may resist tension and compression. A textile member  57  may also be utilized and may have the configuration of either a woven or knit textile. In some configurations, textile member  57  may be a spacer knit textile. A truss member  58  may also be utilized in chamber  33  and has the configuration of a semi-rigid polymer element that extends between plates  51  and  52 . Additionally, a telescoping member  59  that freely collapses but also resists tension may be utilized. Accordingly, a variety of other materials or structures may be utilized with tethers  53  or in place of tethers  53 . 
     Although a single plate  51  and a single plate  52  may be utilized in chamber  33 , some configurations may incorporate multiple plates  51  and  52 . Referring to  FIG. 12G , two plates  51  and two plates  52  are located within the interior cavity of barrier  40 . An advantage to this configuration is that each of plates  51  may deflect independently when compressed by the foot. A similar configuration is depicted in  FIG. 12H , wherein a central bond  45  joins barrier portions  41  and  42  in the central area of chamber  33 . Bond  45  may, for example, form separate subchambers within chamber  33 , which may be pressurized differently to affect the compressibility of different areas of chamber  33 . As an additional matter, each of plates  51  or each of plates  52  may be formed from different materials to impart different properties to various areas of chamber  33 . 
     A further configurations of chamber  33  is depicted in  FIG. 12I  as including a tether element  60  that has an upper tie piece  61 , a lower tie piece  62 , and a tether  63 . Whereas upper tie piece  61  is secured, bonded, or otherwise joined to upper barrier portion  41 , lower tie piece  62  is secured, bonded, or otherwise joined to lower barrier portion  42 . Additionally, tether  63  is joined to each of tie pieces  61  and  62  and extends through the interior cavity. In this configuration, tether  63  is placed in tension by the outward force of the pressurized fluid within chamber  33 . Tie pieces  61  and  62  are similar to plates  51  and  52 , but are generally associated with a single tether  63  or a relatively small number of tethers  63 , rather than multiple tethers. Although tie pieces  61  and  62  may be round disks with common diameters, tie pieces  61  and  62  may have any shape or size. By modifying the lengths of tethers  63 , various contours may be imparted to chamber  33 . For example,  FIG. 12J  depicts chamber  33  as having a tapered configuration, and  FIG. 12K  depicts chamber  33  as having a central depression. In further configurations, tie pieces  61  and  62  may be offset from each other to impart a diagonal configuration to tethers  63 , as depicted in  FIG. 12L . 
     Some configurations of chamber  33  may have both a tether element  50  and one or more tether elements  60 , as depicted in  FIG. 12M . That is, chamber  33  may have (a) a first area that includes tether element  50  and (b) a second area that includes a plurality of tether elements  60 . Given the difference in sizes of tether element  50  and the individual tether elements  60 , the compression characteristics of chamber  33  differ in areas where tether element  50  is present and in areas where tether elements  60  are present. More particularly, the deflection of chamber  33  when a force is applied to a particular area may be different, depending upon the type of tether element that is utilized. Accordingly, tether element  50  and tether elements  60  may both be utilized in chamber  33  to impart different compression characteristics to different areas of chamber  33 . 
     As discussed above, chamber  33  may have (a) a first area that includes tether element  50  and (b) a second area that includes a plurality of tether elements  60  in order to impart different compression characteristics to the first and second areas of chamber  33 . As an example, the plurality of tether elements  60  may be utilized in lateral side  14  to impart greater deflection as the heel compresses sole structure  30 , and tether element  50  may be utilized in medial side  15  to impart a stiffer deflection as the foot rolls or pronates toward medial side  15 . As another example, the plurality of tether elements  60  may be utilized in heel region  13  to impart greater deflection as the heel compresses sole structure  30 , and tether element  50  may be utilized in forefoot region  11  to impart a stiffer deflection. In other configurations, the plurality of tether elements  60  may be utilized in forefoot region  11  and tether elements  60  may be utilized in heel region  13 . In either configuration, however, tether element  50  and a plurality of tether elements  60  may be utilized in combination to impart different compression characteristics to different areas of footwear  10 . Moreover, any of the additional tether element configurations shown in  FIG. 12F  may be utilized in combination with tether element  50  and one or more of tether elements  60  to vary the compression characteristics in different areas of chamber  33  or other chambers. 
     Some conventional chambers utilize bonds between opposite surfaces to prevent the barrier from expanding outward and retaining the intended shape of the chamber. Often, the bonds form indentations or depressions in the upper and lower surfaces of the chamber and have different compression characteristics than other areas of the chamber (i.e., the areas without the bonds). Referring to  FIG. 12N , chamber  33  has a configuration wherein areas with the various tether elements  60  form indentations in barrier portions  41  and  42 . That is, barrier portions  41  and  42  form depressions in areas where tie pieces  61  and  62  are secured to barrier  40 . In some configurations, these depressions may be molded or otherwise formed in barrier portions  41  and  42 , or barrier  40  may take this shape due to the pressure of the fluid within barrier  40 . In other configurations, a variety of other tensile members (e.g., foam members, spacer textiles) may be utilized in place of tether elements  60 . 
     Second Chamber Configuration 
     The various configurations of chamber  33  discussed above provide examples of fluid-filled chambers that may be incorporated into footwear  10  or other articles of footwear. A variety of other fluid-filled chambers may also be incorporated into footwear  10  or the other articles of footwear, including a chamber  100 . Referring to  FIGS. 13-17B , chamber  100  has a barrier  110  and a plurality of tether elements  120 . Barrier  110  forms an exterior of chamber  100  and defines an interior cavity for receiving both a pressurized fluid and tether elements  120 . Barrier  110  includes a first or upper barrier portion  111 , an opposite second or lower barrier portion  112 , and a sidewall barrier portion  113  that extends around a periphery of chamber  100  and between barrier portions  111  and  112 . In addition, barrier  110  includes a peripheral bond  114 , which may be absent in some configurations. Tether elements  120  are located within the interior cavity and have the configurations of textile or polymer sheets, for example. Either adhesive bonding or thermobonding, for example, may be utilized to secure tether elements  120  to barrier  110 . Any of the manufacturing processes, materials, fluids, fluid pressures, and other features of barrier  40  discussed above may also be utilized for barrier  110 . 
     Tether elements  120  are secured to each of barrier portions  111  and  112  in order to retain the intended shape of chamber  100  when pressurized. More particularly, tether elements  120  extend across the interior cavity and are placed in tension by the outward force of the pressurized fluid upon barrier  110 , thereby preventing barrier  110  from expanding outward and retaining the intended shape of chamber  100 . That is, tether elements  120  prevent chamber  100  from expanding outward or otherwise distending due to the pressure of the fluid. 
     Although a variety of materials may be utilized, tether elements  120  may be formed from any generally two-dimensional material. As utilized with respect to the present invention, the term “two-dimensional material” or variants thereof is intended to encompass generally flat materials exhibiting a length and a width that are substantially greater than a thickness. Accordingly, suitable materials for tether elements  120  include various textiles, polymer sheets, or combinations of textiles and polymer sheets, for example. Textiles are generally manufactured from fibers, filaments, or yarns that are, for example, either (a) produced directly from webs of fibers by bonding, fusing, or interlocking to construct non-woven fabrics and felts or (b) formed through a mechanical manipulation of yarn to produce a woven or knitted fabric. The textiles may incorporate fibers that are arranged to impart one-directional stretch or multi-directional stretch. The polymer sheets may be extruded, rolled, or otherwise formed from a polymer material to exhibit a generally flat aspect. Two-dimensional materials may also encompass laminated or otherwise layered materials that include two or more layers of textiles, polymer sheets, or combinations of textiles and polymer sheets. In addition to textiles and polymer sheets, other two-dimensional materials may be utilized for tether elements  120 . In some configurations, mesh materials or perforated materials may be utilized for tether elements  120 . 
     Each of tether elements  120  are formed from a single element of a two-dimensional material, such as a textile or polymer sheet. Moreover, each of tether elements  120  have an upper end area  121 , a lower end area  122 , and a central area  123 . Whereas upper end area  121  is secured, bonded, or otherwise joined to upper barrier portion  111 , lower end area  122  is secured, bonded, or otherwise joined to lower barrier portion  112 . In this configuration, central area  123  extends through the interior cavity and is placed in tension by the outward force of the pressurized fluid within chamber  100 . 
     Although the structure of chamber  100  discussed above and depicted in the figures provides a suitable example of a configuration that may be utilized in footwear  10 , a variety of other configurations may also be utilized. Referring to  FIG. 18A , tether elements  120  are secured to offset areas of barrier portions  111  and  112  in order to impart a diagonal orientation to central areas  123 . More particularly, end areas  121  and  122  are secured to offset locations to induce the slanting or diagonal orientation in central areas  123 . As discussed above, the diagonal orientation resists deformation in chamber  100 , thereby enhancing the overall stability of footwear  10  during walking, running, or other ambulatory activities. Referring to  FIG. 18B , a single tether element  120  is joined to barrier portions  111  and  112  in various locations and has a zigzagging configuration within chamber  100 . By modifying the lengths of tether elements  120 , various contours may be imparted to chamber  100 . For example,  FIG. 18C  depicts chamber  100  as having a tapered configuration, and  FIG. 18D  depicts chamber  100  as having a central depression. Each of these contours are formed by selectively utilizing tether elements  120  with varying lengths. 
     Third Chamber Configuration 
     In the various configurations of chamber  100  discussed above, each of tether elements  120  are formed from a single element of a two-dimensional material. In some configurations, two or more elements of a two-dimensional material may be utilized to form tether elements. Referring to  FIGS. 19-23B , a chamber  200  having a barrier  210  and a plurality of tether elements  220  is depicted. Barrier  210  forms an exterior of chamber  200  and defines an interior cavity for receiving both a pressurized fluid and tether elements  220 . Barrier  210  includes a first or upper barrier portion  211 , an opposite second or lower barrier portion  212 , and a sidewall barrier portion  213  that extends around a periphery of chamber  200  and between barrier portions  211  and  212 . In addition, barrier  210  includes a peripheral bond  214 , which may be absent in some configurations. Tether elements  220  are located within the interior cavity and are formed from at least two elements of a two-dimensional material, such as textile or polymer sheets. Either adhesive bonding or thermobonding, for example, may be utilized to secure tether elements  220  to barrier  210 . 
     Tether elements  220  are secured to each of barrier portions  211  and  212  in order to retain the intended shape of chamber  200  when pressurized. More particularly, tether elements  220  extend across the interior cavity and are placed in tension by the outward force of the pressurized fluid upon barrier  210 , thereby preventing barrier  210  from expanding outward and retaining the intended shape of chamber  200 . That is, tether elements  220  prevent chamber  200  from expanding outward or otherwise distending due to the pressure of the fluid. Each of tether elements  220  are formed from an upper sheet  221  that is joined to upper barrier portion  211  and a lower sheet  222  that is joined to lower barrier portion  212 . Each of sheets  221  and  222  have an incision or cut that forms a central tab  223 . Whereas peripheral areas of sheets  221  and  222  are joined with barrier  210 , tabs  223  are unsecured and extend into the interior cavity. End areas of both tabs  223  contact each other and are joined to secure sheets  221  and  222  together. When chamber  200  is pressurized, tabs  223  are placed in tension and extend across the interior cavity, thereby preventing chamber  200  from expanding outward or otherwise distending due to the pressure of the fluid. 
     Any of the manufacturing processes, materials, fluids, fluid pressures, and other features of barrier  40  discussed above may also be utilized for barrier  210 . In order to prevent tabs  223  from being bonded to barrier  210 , a blocker material may be utilized. More particularly, a material that inhibits bonding between tabs  223  and barrier  210  (e.g., polyethylene terephthalate, silicone, polytetrafluoroethylene) may be utilized to ensure that tabs  223  remain free to extend across the interior cavity between barrier portions  211  and  212 . In many configurations, the blocker material may be located on tabs  223 , but may also be on surfaces of barrier  210  or may be a film, for example, that extends between tabs  223  and surfaces of barrier  210 . 
     Although the structure of chamber  200  discussed above and depicted in the figures provides a suitable example of a configuration that may be utilized in footwear  10 , a variety of other configurations may also be utilized. Referring to  FIG. 24A , tether elements  220  are secured to offset areas of barrier portions  211  and  212  in order to impart a diagonal orientation. Referring to  FIG. 24B , a single sheet  221  and a single sheet  222  define a plurality of tabs  223 . Whereas each of sheets  221  and  222  may form a single tab  223 , sheets  221  and  222  may form multiple tabs  223 . By modifying the lengths of tabs  223 , various contours may be imparted to chamber  200 . For example,  FIG. 24C  depicts chamber  200  as having a tapered configuration, and  FIG. 24D  depicts chamber  200  as having a central depression. Each of these contours are formed by selectively utilizing tabs  223  with varying lengths. 
     Fourth Chamber Configuration 
     Another configuration wherein two or more elements of a two-dimensional material are utilized to form tether elements is depicted as a chamber  300  in  FIGS. 25-29B . Chamber  300  having a barrier  310  and a plurality of tether elements  320 . Barrier  310  forms an exterior of chamber  300  and defines an interior cavity for receiving both a pressurized fluid and tether elements  320 . Barrier  310  includes a first or upper barrier portion  311 , an opposite second or lower barrier portion  312 , and a sidewall barrier portion  313  that extends around a periphery of chamber  300  and between barrier portions  311  and  312 . In addition, barrier  310  includes a peripheral bond  314 , which may be absent in some configurations. Tether elements  320  are located within the interior cavity and are formed from at least two elements of a two-dimensional material, such as textile or polymer sheets. Either adhesive bonding or thermobonding, for example, may be utilized to secure tether elements  320  to barrier  310 . 
     Tether elements  320  are secured to each of barrier portions  311  and  212  in order to retain the intended shape of chamber  300  when pressurized. More particularly, tether elements  320  extend across the interior cavity and are placed in tension by the outward force of the pressurized fluid upon barrier  310 , thereby preventing barrier  310  from expanding outward and retaining the intended shape of chamber  300 . That is, tether elements  320  prevent chamber  300  from expanding outward or otherwise distending due to the pressure of the fluid. Each of tether elements  320  are formed from an upper sheet  321  that is joined to upper barrier portion  311  and a lower sheet  322  that is joined to lower barrier portion  312 . Each of sheets  321  and  322  have circular or disk-shaped configuration. Whereas peripheral areas of sheets  321  and  322  are joined with each other, central areas are joined to barrier portions  311  and  312 . Once placed in tension, sheets  321  and  322  may distend to form the shapes seen in the various figures. When chamber  300  is pressurized, sheets  321  and  322  are placed in tension and extend across the interior cavity, thereby preventing chamber  300  from expanding outward or otherwise distending due to the pressure of the fluid. 
     Any of the manufacturing processes, materials, fluids, fluid pressures, and other features of barrier  40  discussed above may also be utilized for barrier  310 . In order to prevent peripheral areas of sheets  321  and  322  from being bonded to barrier  210 , a blocker material may be utilized. More particularly, a material that inhibits bonding between the peripheral areas of sheets  321  and  322  and barrier  310  may be utilized to ensure that sheets  321  and  322  remain free to extend across the interior cavity. 
     Although the structure of chamber  300  discussed above and depicted in the figures provides a suitable example of a configuration that may be utilized in footwear  10 , a variety of other configurations may also be utilized. Referring to  FIG. 30A , the peripheral areas of sheets  321  and  322  are bonded to barrier  310 , whereas the central areas of sheets  321  and  322  are bonded to each other. By modifying the diameters or other dimensions of sheets  321  and  322 , various contours may be imparted to chamber  200 . For example,  FIG. 30B  depicts chamber  300  as having a tapered configuration, but a central depression or other contour may also be formed by selectively varying the dimensions of sheets  321  and  322 . 
     Fifth Chamber Configuration 
       FIG. 31  shows a fifth chamber  400  that may be used in the article of footwear  10 . The chamber  400  has a barrier  402  formed from a polymer material. For example, the barrier  402  may be formed from a first polymer sheet  404  and a second polymer sheet  406  bonded to one another at a peripheral bond  408 . The chamber  400  may be formed as described with respect to chamber  33 , and the polymer material from which the chamber  400  is formed may be any of the materials described with respect to chamber  33 , such as a gas barrier polymer capable of retaining a pressurized gas such as air or nitrogen, as discussed with respect to chamber  33 . 
     For example, the first and second polymer sheets  404 ,  406  are bonded to one another at the peripheral bond  408  to form at least one interior cavity  410 A. In the embodiment of  FIG. 32 , the first polymer sheet  404  and the second polymer sheet  406  are also bonded to one another at several intermediate locations  409 , referred to as webbing, surrounded by the peripheral bond  408 . The additional bonding at locations  409  causes the first and second polymer sheets  404 ,  406  to form and define multiple interior cavities, such as the interior cavities  410 A,  410 B,  410 C,  410 D,  410 E,  410 F, and  410 G. For purposes of discussion, interior cavity  410 A is referred to as a first interior cavity, and interior cavity  410 B is referred to as a second interior cavity. The interior cavities are also referred to as pods, and the barrier  402  is referred to as podular. In other embodiments, the first polymer sheet  404  may be bonded to the second polymer sheet  406  only at the peripheral bond  408  so that only a single, large interior cavity is formed. The first and second sheets  404 ,  406  may be shaped and bonded to one another in a thermoforming mold assembly. The second sheet  406  is molded to have stiffening ribs  413  in the midfoot region  12 . 
     As shown in  FIG. 31 , the first and second polymer sheets  404 ,  406  also form channels  411  between various adjacent ones of the interior cavities  410 A,  410 B,  410 C,  410 D,  410 E,  410 F, and  410 G so that the interior cavities  410 A,  410 B,  410 C,  410 D,  410 E,  410 F, and  410 G are fluidly interconnected, and may be filled with fluid through a common port between the sheets  404 ,  406 , which is then plugged. Alternatively, one or more of the various interior cavities  410 A,  410 B,  410 C,  410 D,  410 E,  410 F, and  410 G can be isolated from the remaining interior cavities so that different fluid pressures can be maintained within the various interior cavities  410 A,  410 B,  410 C,  410 D,  410 E,  410 F, and  410 G. 
     As shown in  FIG. 33 , the first polymer sheet  404  includes a first portion or upper barrier portion  412 . The second polymer sheet  406  includes a second portion or lower barrier portion  414 , as well as a sidewall barrier portion  416 . The first barrier portion  412  forms a first surface of the barrier  402 , which is an inner surface  418  of the first polymer sheet  404 . The second barrier portion  414  forms a second surface of the barrier  402  opposite to the inner surface  418 . The second surface is an inner surface  420  of the second polymer sheet  406 . As discussed, portions of the inner surfaces  418 ,  420  are bonded to one another at the web  409 . 
     Different tethers of different configurations can be in the at least one of the interior cavities, operatively connecting the first portion to the second portion, and providing different compression characteristics to the chamber  400  at different areas of the chamber  400 . Various tether elements are within the interior cavities and operatively connect the inner surface  418  to the inner surface  420 . For example, with reference to  FIGS. 31 and 32 , a first tether element  450 A is positioned in the first interior cavity  410 A, a second tether element  450 B is positioned in the second interior cavity  410 B, and additional tether elements  450 C,  450 D,  450 E,  450 F, and  450 G are positioned in interior cavities  410 C,  410 D,  410 E,  410 F, and  410 G, respectively. The tether elements  450 A,  450 B,  450 C,  450 D,  450 E,  450 F,  450 G may be configured as described with respect to tether element  50  discussed herein. For example, as shown in  FIG. 33 , the first tether element  450 A includes a first plate  451 A secured to the inner surface  418  of the first portion  412 , and a second plate  452 A secured to the inner surface  420  of the second portion  414 . The plates  451 A,  452 A can be a thermoplastic material that thermally bonds to the first and second polymer sheets  404 ,  406  during thermoforming of the polymer sheets  404 ,  406 . 
     A plurality of first tethers  453 A having a first configuration are secured to the first plate  451 A and the second plate  452 A and placed in tension between the plates  451 A,  452 A by fluid in the interior cavity  410 A. Multiple rows of tethers  453 A are present and extend across a width of the tether element  450 A. Each tether  453 A shown in the cross-section of  FIG. 32  is in a different one of the rows. The tethers  453 A may be a variety of configurations, such as described with respect to tethers in  FIGS. 1-30C , including single strands secured at each end to plates  451 A,  452 A, or repeatedly passing through one or both plates  451 A,  452 A. The tethers  453 A therefore operatively connect the first portion  412  of the barrier  402  to the second portion  414  of the barrier  402  at a first area A 1  of the chamber  400 . The first area A 1  is generally the area of the barrier  402  above and below the tether element  450 A in  FIG. 32 , and is represented by the area of the second plate  452 A shown in  FIG. 31 . 
     The second tether element  450 B includes a plurality of second tethers  453 B having a second configuration that are secured to a third plate  451 B and the fourth plate  452 B and placed in tension between the plates  451 B,  452 B by fluid in the interior cavity  410 B. Multiple rows of tethers  453 B are present, and each tether  453 B shown represents a single row. The third plate  451 B is secured to the inner surface  418  of the first polymer sheet  404  in the second interior cavity  410 B, and the fourth plate  452 B is secured to the inner surface  420  of the second polymer sheet  406  in the second interior cavity  410 B. The tethers  453 B may be a variety of configurations, such as described with respect to tethers  53  in  FIGS. 8A-9D , including single strands secured at each end to plates  451 B,  452 B, or repeatedly passing through one or both plates  451 B,  452 B. The tethers  453 B therefore operatively connect the first portion  412  of the barrier  402  to the second portion  414  of the barrier  402  at a second area A 2  of the chamber  400  via the plates  451 B,  452 B. The second area A 2  is generally the area of the barrier  402  above and below the tether element  450 B in  FIG. 32 , and is represented by the area of the third plate  452 B in  FIG. 31 . 
     As shown in  FIG. 31 , the first area A 1  of the first tether element  450 A is in the heel region  13  of the chamber  400 , and the second area A 2  of the second tether element  450 B is in the forefoot region  11  of the chamber  400 . Although the first and second tethers  453 A,  453 B are shown and described with respect to separate tether elements  450 A,  450 B in separate interior cavities  410 A,  410 B, the differently configured first and second tethers  453 A,  453 B could instead be within the same tether element, i.e., attached between the same two plates, such as is shown and described with respect to the embodiments of  FIGS. 34-37 . 
     The first configuration of the first plurality of tethers  453 A imparts a first compression characteristic to the chamber  400  at the first area A 1 , and the second configuration of the second plurality of tethers  453 B imparts a second compression characteristic different than the first compression characteristic to the chamber  400  at the second area A 2 . For example, as shown in  FIG. 32 , the tethers  453 A are longer than the tethers  453 B, enabling the first polymer sheet  404  to be spaced further from the second polymer sheet  406  in the interior cavity  410 A than in the interior cavity  410 B under pressure from the fluid in the interior cavity  410 A. Depression of the chamber  400  under loading may be greater in the heel region  13  than in the forefoot region  11  and the greater lengths of the tethers  453 A may provide greater cushioning in the heel region  13 . Pluralities of tethers  453 C and  453 D within the interior cavities  410 C and  410 D in the forefoot portion  11  and midfoot portion  12 , respectively, have lengths greater than tethers  453 B and less than tethers  453 A. The lengths of the tethers of the tether elements  450 B,  450 C,  450 D,  450 A in the chamber  400  thus increase from the forefoot region  11  to the heel region  13 . Additionally or alternatively, the tethers  453 A could be thicker or thinner than tethers  453 B, or could be a different material than the tethers  453 B, imparting different compression characteristics to the chamber  400  at the first area A 1  than at the second area A 2 . The tethers  453 A could be spaced more densely relative to one another than the tethers  453 B, or tethers  453 B could be spaced more densely relative to one another than the tethers  453 A, within the same row of tethers, or adjacent rows could be spaced more densely to impart different compression characteristics. 
     Sixth Chamber Configuration 
       FIGS. 34 and 35  show a sixth chamber  500  with multiple interior cavities containing different tether elements, at least some of which have different pluralities of tethers having different configurations in the same tether element. For example, a first plurality of tethers  553 A with a first configuration is bordered by and may be partially or completely surrounded by a second plurality of tethers  553 AA with a second configuration in the same tether element  550 A. The chamber  500  has a barrier  502  formed from a polymer material. For example, the barrier  502  may be formed from a first polymer sheet  504  and a second polymer sheet  506  bonded to one another at a peripheral bond  508 . The chamber  500  may be formed as described with respect to chamber  33 , and the polymer material from which the chamber  500  is formed may be any of the materials described with respect to chamber  33 , such as a gas barrier polymer capable of retaining a pressurized gas such as air or nitrogen, as discussed with respect to chamber  33 . 
     For example, the first and second polymer sheets  504 ,  506  are bonded to one another at the peripheral bond  508  to form at least one interior cavity  510 A. In the embodiment of  FIG. 34 , the first polymer sheet  504  and the second polymer sheet  506  are also bonded to one another at several intermediate locations  509 , referred to as webbing, surrounded by the peripheral bond  508 . The additional bonding at locations  509  causes the first and second polymer sheets  504 ,  506  to form and define multiple interior cavities, such as the interior cavities  510 A,  510 B, and  510 C. For purposes of discussion, interior cavity  510 A is referred to as a first interior cavity, and interior cavity  510 B is referred to as a second interior cavity. The interior cavities are also referred to as pods, and the barrier  502  is referred to as podular. In other embodiments, the first polymer sheet  504  may be bonded to the second polymer sheet  506  only at the peripheral bond  508  so that only a single, large interior cavity is formed. The first and second sheets  504 ,  506  may be shaped and bonded to one another in a thermoforming mold assembly. 
     As shown in  FIG. 34 , the first and second polymer sheets  504 ,  506  also form channels  511  between various adjacent ones of the interior cavities  510 A,  510 B, and  510 C so that the interior cavities  510 A,  510 B, and  510 C are fluidly interconnected, and may be filled with fluid through a common port between the sheets  504 ,  506 , which is then plugged. Alternatively, one or more of the various interior cavities  510 A,  510 B, and  510 C can be isolated from the remaining interior cavities so that different fluid pressures can be maintained within the various interior cavities  510 A,  510 B, and  510 C. 
     As shown in  FIG. 35 , the first polymer sheet  504  includes a first portion or upper barrier portion  512 . The second polymer sheet  506  includes a second portion or lower barrier portion  514 A, as well as a sidewall barrier portion  516 . The first barrier portion  512  forms a first surface of the barrier  502 , which is an inner surface  518  of the first polymer sheet  504 . The second barrier portion  514  forms a second surface of the barrier  502  opposite to the inner surface  518 . The second surface is an inner surface  520  of the second polymer sheet  506 . As discussed, portions of the inner surfaces  518 ,  520  are bonded to one another at the web  509 . 
     Different tethers of different configurations can be in the at least one interior cavity  510 A, operatively connecting the first portion  512  to the second portion  514 , and providing different compression characteristics to the chamber  500  at different areas of the chamber  500 . Various tether elements are within the interior cavities and operatively connect the inner surface  518  to the inner surface  520 . For example, with reference to  FIG. 35 , a first tether element  550 A is positioned in the first interior cavity  510 A, a second tether element  550 B is positioned in the second interior cavity  510 B, and an additional tether element  550 C is positioned in interior cavity  510 C. The tether elements  550 A,  550 B,  550 C may be configured as described with respect to tether element  50  discussed herein. For example, as shown in  FIG. 35 , the first tether element  550 A includes a first plate  551 A secured to the inner surface  518  of the first portion  512 , and a second plate  552 A secured to the inner surface  520  of the second portion  514 . The plates  551 A,  552 A can be a thermoplastic material that thermally bonds to the first and second polymer sheets  504 ,  506  during thermoforming of the polymer sheets  504 ,  506 . 
     A plurality of first tethers  553 A having a first configuration are secured to the first plate  551 A and the second plate  552 A and placed in tension between the plates  551 A,  552 A by fluid in the interior cavity  510 A. The tethers  553 A may be a variety of configurations, such as described with respect to tethers  53  in  FIGS. 8A-9D , including single strands secured at each end to plates  551 A,  552 A, or repeatedly passing through one or both plates  551 A,  552 A. The tethers  553 A therefore operatively connect the first portion  512  of the barrier  502  to the second portion  514  of the barrier  502  at a first area A 11  of the chamber  500 . The first area A 11  is generally the area of the barrier  502  above and below the tethers  553 A in  FIG. 35 , and can be represented by the area within the phantom line  570 A in  FIG. 34 . 
     A plurality of second tethers  553 AA are also attached to the same first plate  551 A and second plate  552 A as the plurality of first tethers  553 A in the same first interior cavity  510 A. The second tethers  553 AA are operatively connected to the first portion  512  of the barrier  502  and to the second portion  514  of the barrier  502  at a second area of the chamber  500 . The second area is generally the area above and below the tethers  553 AA in  FIG. 35  and can be represented by the area A 21  between the hidden line of the boundary of the tether element  550 A and the phantom line  570 A representing the boundary of the area A 11  of the first tethers  553 A. Accordingly, the second area A 21  borders the first area A 11  and surrounds the first area A 11 . The tethers  553 A and the tethers  553 AA are both in the heel region  13  of the chamber  500 . 
     The first configuration of the first plurality of tethers  553 A imparts a first compression characteristic to the chamber  500  at the first area A 1 , and the second configuration of the second plurality of tethers  553 B imparts a second compression characteristic different than the first compression characteristic to the chamber  500  at the second area A 21 . For example, as shown in  FIG. 35 , the tethers  553 A are less dense (i.e., spaced further from one another) than the tethers  553 AA. Depression of the chamber  500  under loading may be greater in the area A 11  than in the area A 21  due to the less dense tethers  553 A, potentially providing greater cushioning in the area A 11  of the heel region  13 . Additionally or alternatively, the tethers  553 A could be thicker or thinner than tethers  553 AA, or could be a different material than the tethers  553 AA, imparting different compression characteristics to the chamber  500  at the first area A 11  than at the second area A 21 . The tethers  553 A could be longer or shorter than the tethers  553 AA, either within the same row, or adjacent rows to impart different compression characteristics. For example, the tethers  553 A and  553 AA could be any of the tethers shown and described with respect to  FIGS. 1-30C . 
     The second tether element  550 B includes a plurality of tethers  553 B having a second configuration that are secured to a third plate  551 B and the fourth plate  552 B and placed in tension between the plates  551 B,  552 B by fluid in the interior cavity  510 B. The third plate  551 B is secured to the inner surface  518  of the first polymer sheet  504  in the second interior cavity  510 B, and the fourth plate  552 B is secured to the inner surface  520  of the second polymer sheet  506  in the second interior cavity  510 B. The tethers  553 B may be a variety of configurations, such as described with respect to tethers in  FIGS. 1-30C , including single strands secured at each end to plates  551 B,  552 B, or repeatedly passing through one or both plates  551 B,  552 B. The tethers  553 B therefore operatively connect the first portion  512  of the barrier  502  to the second portion  514  of the barrier  502  at an area A 12  of the chamber  500  via the plates  551 B,  552 B. The area A 12  is generally the area of the barrier  502  above and below the tethers  553 B in  FIG. 35 , and can be partially represented by the area A 12  within the phantom boundary line  570 B in  FIG. 34 . Differently configured tethers  553 B are connected to the plates  551 B and  552 B generally bordering and surrounding the tethers  553 B and impart a compression characteristic to the chamber  500  at the area A 22  in  FIG. 34 . The tethers  553 B and the tethers  553 BB are both in the forefoot region  11  of the chamber  500 . 
     The tether element  550 C includes a plurality of tethers  553 C that are secured to a plate  551 C and a plate  552 C and placed in tension between the plates  551 C,  552 C by fluid in the interior cavity  510 C. The plate  551 C is secured to the inner surface  518  of the first polymer sheet  504  in the interior cavity  510 C, and the plate  552 C is secured to the inner surface  520  of the second polymer sheet  506  in the second interior cavity  510 C. The tethers  553 C may be a variety of configurations, such as described with respect to tethers  53  in  FIGS. 1-30C , including single strands secured at each end to plates  551 C,  552 C, or repeatedly passing through one or both plates  551 C,  552 C. The tethers  553 C therefore operatively connect the first portion  512  of the barrier  502  to the second portion  514  of the barrier  502  at an area A 13  of the chamber  500  via the plates  551 C,  552 C. The area A 13  is generally the area of the barrier  502  above and below the tethers  553 C in  FIG. 35 , and can be partially represented by the area A 13  within the phantom boundary lines  570 C and  570 D in  FIG. 34 . Differently configured tethers  553 CC are connected to the plates  551 C and  552 C generally bordering and surrounding the tethers  553 C and impart a compression characteristic to the chamber  500  at the area A 23  in  FIG. 34 . The area A 23  surrounds area A 13 . The area A 13  is split into two sub-areas by the surrounding area A 23 . The tethers  553 C and the tethers  553 CC are both in the midfoot region  12  of the chamber  500 . 
     Seventh Chamber Configuration 
       FIG. 36  shows a chamber  600  configured similarly to chamber  500  except with an additional interior cavity. The chamber  600  is formed from first and second polymer sheets having multiple interior cavities  610 A,  610 B,  610 C,  610 D fluidly connected with one another by channels  611 , as described with respect to chamber  500 , and has tether elements  650 A,  650 B,  650 C, and  650 D within the interior cavities. The tether elements  650 A,  650 B, and  650 C are configured similarly to tether elements  550 A,  550 B, and  550 C, respectively, with plates secured to inner surfaces of the first and second polymer sheets, and different configuration of tethers connecting the plates. The tether elements can be any of those shown and described herein, such as in  FIGS. 1-35 . Accordingly, a phantom boundary line  670 A separates a first plurality of tethers having a first configuration from a second plurality of tethers having a second configuration in the interior cavity  610 A. Different compression characteristics are provided at the different areas. A phantom boundary line  670 B separates areas of the chamber  600  having different compression characteristics due to the different configurations of tethers in the interior cavity  610 B. Phantom boundary lines  670 C and  670 D separate different configurations of tethers in the interior cavity  610 C. Tether element  650 D includes first and second plates connected by tethers that may all be of a first configuration. 
     Eighth Chamber Configuration 
       FIG. 37  shows a chamber  700  configured with only two interior cavities, including chamber  710 A which extends over the forefoot region  11 , the midfoot region  12 , and the heel region  13 . The chamber  700  is formed from first and second polymer sheets having multiple interior cavities  710 A and  710 B fluidly connected with one another by a channel  711 , as described with respect to chamber  500 , and has tether elements  750 A and  750 B within the interior cavities  710 A,  710 B. The interior cavity  710 A extends from and is in the forefoot region  11  to the heel region  13  and is in the forefoot region  11 , the midfoot region  12 , and the heel region  13 . The tether elements  750 A and  750 B are configured similarly to tether elements  550 A and  550 B, with plates secured to inner surfaces of the first and second polymer sheets, and different configuration of tethers connecting the plates. Accordingly, a phantom boundary line  770 A separates a first plurality of tethers having a first configuration from a second plurality of tethers having a second configuration in the interior cavity  710 A. The second plurality of tethers is in the area between the boundary of the tether element  750 A and the phantom boundary lines  770 A,  770 A 1 ,  770 A 2 , and  770 A 3 . Boundary lines  770 A 1 ,  770 A 2 , and  770 A 3  separate additional pluralities of tethers, which may be of the same or of different configurations from the first plurality of tethers, from the second plurality of tethers that surround each of the plurality of tethers within the boundary lines  770 A,  770 A 1 ,  770 A 2 , and  770 A 3 . The tether elements can be any of those shown and described herein, such as in  FIGS. 1-35 . 
     In the interior cavity  710 B, the tether element  750 B has configurations of tethers connected to first and second plates and operatively connecting the first and second polymer sheets and within the boundary lines  770 B 1  and  770 B 2 . A plurality of tethers of a different configuration is in the area between the boundary of the tether element  750 B and the phantom boundary lines  770 B 1  and  770 B 2 . 
     CONCLUSION 
     The above discussion and various figures disclose a variety of fluid-filled chambers that may be utilized in footwear  10  or other articles of footwear, as well as a variety of other products (e.g., backpack straps, mats for yoga, seat cushions, and protective apparel). Although many of the concepts regarding the barriers and tensile elements are discussed individually, fluid-filled chambers may gain advantages from combinations of these concepts. That is, various types of tether elements may be utilized in a single chamber to provide different properties to different areas of the chamber. For example,  FIG. 30C  depicts a configuration wherein chamber  300  includes each of tensile elements  60 ,  120 ,  220 , and  320 , as well as fluid-filled member  55 , foam member  56 , and truss member  58 . Whereas tensile elements  60 ,  120 ,  220 , and  320  may have a configuration that collapses with the compression of chamber  300 , members  55 ,  56 , and  58  may form more rigid structures that resist collapsing. This configuration may be utilized, therefore, to impart compressibility to one area of chamber  300 , while limiting compressibility in another area. Accordingly, various types of tensile elements may be utilized to impart different properties to a fluid-filled chamber. 
     While several modes for carrying out the many aspects of the present teachings have been described in detail, those familiar with the art to which these teachings relate will recognize various alternative aspects for practicing the present teachings that are within the scope of the appended claims. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not as limiting.