Patent Publication Number: US-10306946-B2

Title: Article of footwear having heel portion with knitted component

Description:
BACKGROUND 
     Conventional articles of footwear generally include two primary elements an upper and a sole structure. The upper is secured to the sole structure and forms a void within the footwear for comfortably and securely receiving a foot. The sole structure is secured to a lower surface of the upper so as to be positioned between the upper and the ground. In some articles of athletic footwear, for example, the sole structure may include a midsole and an outsole. The midsole may be formed from a polymer foam material that attenuates ground reaction forces to lessen stresses upon the foot and leg during walking, running, and other ambulatory activities. The outsole is secured to a lower surface of the midsole and forms a ground-engaging portion of the sole structure that is formed from a durable and wear-resistant material. The sole structure may also include a sockliner positioned within the void and proximal a lower surface of the foot to enhance footwear comfort. 
     The upper generally extends over the instep and toe areas of the foot, along the medial and lateral sides of 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, and the upper may incorporate a heel counter to limit movement of the heel. 
     Various materials are conventionally utilized in manufacturing the upper. The upper of athletic footwear, for example, may be formed from multiple material elements. The materials may be selected based upon various properties, including stretch-resistance, wear-resistance, flexibility, air-permeability, compressibility, and moisture-wicking, for example. With regard to an exterior of the upper, the toe area and the heel area may be formed of leather, synthetic leather, or a rubber material to impart a relatively high degree of wear-resistance. Leather, synthetic leather, and rubber materials may not exhibit the desired degree of flexibility and air-permeability for various other areas of the exterior. Accordingly, the other areas of the exterior may be formed from a synthetic textile, for example. The exterior of the upper may be formed, therefore, from numerous material elements that each imparts different properties to the upper. An intermediate or central layer of the upper may be formed from a lightweight polymer foam material that provides cushioning and enhances comfort. Similarly, an interior of the upper may be formed of a comfortable and moisture-wicking textile that removes perspiration from the area immediately surrounding the foot. The various material elements and other components may be joined with an adhesive or stitching. Accordingly, the conventional upper is formed from various material elements that each imparts different properties to various areas of the footwear. 
     SUMMARY 
     An article of footwear is disclosed that includes a sole structure and an upper coupled to the sole structure. The upper includes a lower edge that is disposed adjacent to the sole structure. The upper further includes a collar defining an opening to a void within the upper. The collar defines an upper edge of the upper that is spaced away from the lower edge. The upper includes a forward portion and a heel portion. The heel portion includes a knitted component of unitary knit construction. The knitted component at least partially defines the upper edge and the lower edge of the upper. The knitted component includes a first side edge that is attached to the forward portion along a first side. The knitted component also includes a second side edge that is attached to the forward portion along a second side. 
     Also, an article of footwear is disclosed that includes a sole structure and an upper coupled to the sole structure. The upper includes a forward portion formed of a first component and a heel portion formed of a second component, the first component being separate from the second component. The forward portion and the heel portion being joined to each other along at least one seam. The heel portion includes a heel knitted component of unitary knit construction. The heel knitted component has a first knitted zone associated with a first amount of stretch resistance and a second knitted zone associated with a second amount of stretch resistance. The first amount of stretch resistance of the first knitted zone is larger than the second amount of stretch resistance of the second knitted zone. 
     Moreover, an article of footwear is disclosed that includes a sole structure and an upper coupled to the sole structure. The upper includes a lower edge that is disposed adjacent the sole structure. The upper includes a collar defining an opening to a void within the upper. The collar defines an upper edge of the upper that is spaced away from the lower edge. The upper also includes a forward portion including a forward knitted component of unitary knit construction. Additionally, the upper includes a heel portion including a heel knitted component of unitary knit construction. The heel portion has a first knitted zone, a second knitted zone, and a third knitted zone. The first knitted zone is associated with a first amount of stretch resistance, the second knitted zone is associated with a second amount of stretch resistance, and the third knitted zone is associated with a third amount of stretch resistance. The first amount of stretch resistance is larger than the second amount of stretch resistance, and the second amount of stretch resistance is larger than the third amount of stretch resistance. The third knitted zone partially defines the collar and the upper edge. The first knitted zone partially defines the lower edge. The second knitted zone is cooperatively surrounded by the first knitted zone and the third knitted zone. The heel knitted component includes a first edge that is joined via stitching to the forward knitted component on a medial side of the upper. The heel knitted component further includes a second edge that is joined via stitching to the forward knitted component on a lateral side of the upper. 
     Other systems, methods, features and advantages of the present disclosure will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the present disclosure, and be protected by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the present disclosure. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1  is a lateral side view of an article of footwear according to exemplary embodiments of the present disclosure; 
         FIG. 2  is a medial side view of the article of footwear of  FIG. 1 ; 
         FIG. 3  is a top view of the article of footwear of  FIG. 1 ; 
         FIG. 4  is a bottom view of an upper of the article of footwear of  FIG. 1 ; 
         FIG. 5  is a rear view of the upper of the article of footwear of  FIG. 1 ; 
         FIG. 6  is a plan view of knitted components of the upper of the article of footwear of  FIG. 1 ; 
         FIG. 7  is a plan view of an exterior surface of a heel knitted component of the upper of the article of footwear of  FIG. 1 ; 
         FIG. 8  is a plan view of an interior surface of a heel knitted component of the upper of the article of footwear of  FIG. 1 ; and 
         FIG. 9  is a plan view of a heel knitted component according to additional embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following discussion and accompanying figures disclose an article of footwear having an upper that includes at least one knitted component. The article of footwear is disclosed as having a general configuration suitable for walking or running. Concepts associated with the footwear, including the upper, may also be applied to a variety of other athletic footwear types, including baseball shoes, basketball shoes, cross-training shoes, cycling shoes, football shoes, soccer shoes, sprinting shoes, tennis shoes, and hiking boots, for example. The concepts may also be applied to footwear types that are generally considered to be non-athletic, including dress shoes, loafers, sandals, and work boots. The concepts disclosed herein apply, therefore, to a wide variety of footwear types. 
     Footwear Configurations 
       FIGS. 1 through 3  illustrate exemplary embodiments of an article of footwear  100 , also referred to simply as footwear  100 . In some embodiments, article of footwear  100  may generally include a sole structure  110  and an upper  120 . 
     For reference purposes, footwear  100  may be divided generally along a longitudinal axis X into three general regions: a forefoot region  101 , a midfoot region  102 , and a heel region  103 . Forefoot region  101  generally includes portions of footwear  100  corresponding with the toes and the joints connecting the metatarsals with the phalanges. Midfoot region  102  generally includes portions of footwear  100  corresponding with an arch area of the foot. Heel region  103  generally corresponds with rear portions of the foot, including the calcaneus bone. Footwear  100  also includes a lateral side  104  and a medial side  105 , which extend through each of forefoot region  101 , midfoot region  102 , and heel region  103  and correspond with opposite sides of footwear  100 . More particularly, lateral side  104  corresponds with an outside area of the foot (i.e., the surface that faces away from the other foot), and medial side  105  corresponds with an inside area of the foot (i.e., the surface that faces toward the other foot). Forefoot region  101 , midfoot region  102 , and heel region  103  and lateral side  104 , medial side  105  are not intended to demarcate precise areas of footwear  100 . Rather, forefoot region  101 , midfoot region  102 , and heel region  103  and lateral side  104 , medial side  105  are intended to represent general areas of footwear  100  to aid in the following discussion. In addition to footwear  100 , forefoot region  101 , midfoot region  102 , and heel region  103  and lateral side  104 , medial side  105  can also independently refer to sole structure  110 , upper  120 , and individual elements thereof. 
     Sole structure  110  can be secured to upper  120  and can extend between the foot and the ground when footwear  100  is worn. In some embodiments, the sole structure  110  can generally include a midsole  111  and an outsole  112 . 
     Midsole  111  can be secured to a lower surface of upper  120  and may be formed from a compressible polymer foam element (e.g., a polyurethane or ethylvinylacetate foam) that attenuates ground reaction forces (i.e., provides cushioning) when compressed between the foot and the ground during walking, running, or other ambulatory activities. In additional embodiments, midsole  111  may incorporate plates, moderators, fluid-filled chambers, lasting elements, or motion control members that further attenuate forces, enhance stability, or influence the motions of the foot. Midsole  111  can also be primarily formed from a fluid-filled chamber. 
     Outsole  112  can be secured to a lower surface of midsole  111 . Outsole  112  can also be formed from a wear-resistant rubber material that is textured to impart traction. 
     The sole structure  110  can further include a sockliner  113  in some embodiments. Sockliner  113  is shown partially in  FIG. 3 . Sockliner  113  can be located within upper  120  and can be positioned to extend under a lower surface of the foot to enhance the comfort of footwear  100 . 
     Although this configuration for sole structure  110  provides an example of a sole structure  110  that may be used in connection with upper  120 , a variety of other conventional or nonconventional configurations for sole structure  110  may also be used. Accordingly, in other embodiments, the features of sole structure  110  or any sole structure used with upper  120  may vary. 
     Upper  120  will now be discussed generally. Upper  120  can define a void  117  within footwear  100  for receiving and securing a foot relative to sole structure  110 . Void  117  is shaped to accommodate the foot and extends along a lateral side of the foot, along a medial side of the foot, over the foot and toes, around the heel, and under the foot. 
     Upper  120  can define a collar  130  with an upper edge  132  that defines an opening  121 . Opening  121  can provide access to void  117  for the wearer&#39;s foot and can be located, at least, in heel region  103 . 
     A tongue  140  can be included forward of collar  130  and can extend longitudinally toward forefoot region  101  and between lateral side  104  and medial side  105 . As shown in the illustrated embodiments, tongue  140  can be integrally attached to forefoot region  101 , lateral side  104 , and medial side  105 . In other embodiments, tongue  140  can be detached from lateral side  104  and medial side  105 . As such, tongue  140  can be moveably received within an open throat area of upper  120  between lateral side  104  and medial side  105 . 
     In some embodiments, closure element  122  can also be included that is used to selectively secure upper  120  to the wearer&#39;s foot. Closure element  122  can be of any suitable type, such as a lace as shown in the illustrated embodiments. In other embodiments, closure element  122  may also include one or more buckles, straps, or other suitable implements for securing upper  120  to a wearer&#39;s foot. 
     In an exemplary embodiment, closure element  122  may be configured to interact with tensile strands  141  to assist with securing upper  120  to a wearer&#39;s foot. In the illustrated embodiment, upper  120  includes a plurality of tensile strands  141  that extend upward along upper  120  from sole structure  110  and extend back down forming looped ends to provide apertures  143  that receive closure element  122 . Tensile strands  141  suitable for use with upper  120  may include the tensile strands and/or tensile elements disclosed in one or more of commonly-owned U.S. patent application Ser. No. 12/338,726 to Dua et al., entitled “Article of Footwear Having An Upper Incorporating A Knitted Component”, filed on Dec. 18, 2008 and published as U.S. Patent Application Publication Number 2010/0154256 on Jun. 24, 2010, and U.S. patent application Ser. No. 13/048,514 to Huffa et al., entitled “Article Of Footwear Incorporating A Knitted Component”, filed on Mar. 15, 2011 and published as U.S. Patent Application Publication Number 2012/0233882 on Sep. 20, 2012, both of which applications are hereby incorporated by reference in their entirety. 
     In this embodiment, apertures  143  provided by strands  141  are spaced apart along axis X and between lateral side  104  and medial side  105 . Accordingly, closure element  122  extends along axis X and alternates between lateral side  104  and medial side  105 . By tensioning closure element  122 , the wearer can modify dimensions of upper  120  to accommodate proportions of the foot. More particularly, closure element  122  can permit the wearer to tighten upper  120  around the foot, and closure element  122  can permit the wearer to loosen upper  120  to facilitate entry and removal of the foot from void  117  through opening  121 . 
     In some configurations, upper  120  can also extend at least partially under the wearer&#39;s foot. For example, sole structure  110  is removed in  FIG. 4 , and as shown upper  120  can include a strobel  125  that is attached along a periphery to a lower edge  160 . Strobel  125  can be attached via stitching  162  as shown in the illustrated embodiments, via fasteners, via adhesives, or via another attachment device. Accordingly, strobel  125  extends under the wearer&#39;s foot. As mentioned above, sole structure  110  can include a sockliner  113  and midsole  111 . In these embodiments, sockliner  113  can be layered over an upper surface of strobel  125  within void  117 , and midsole  111  can be joined to a lower surface of strobel  125 . 
     In further configurations, upper  120  may include additional elements. For example, upper  120  can include a toe guard in forefoot region  101  that is formed of a wear-resistant material. Upper  120  can additionally include logos, trademarks, symbols, and placards with care instructions and material information. Those having ordinary skill in the art will appreciate that upper  120  can include still further elements without departing from the scope of the present disclosure. 
     Many conventional footwear uppers are formed from multiple material elements (e.g., polymer foam, polymer sheets, leather, synthetic leather) that are joined together through stitching or bonding, for example. However, in various embodiments discussed herein, upper  120  can be at least partially formed from a knitted component  130 . Knitted component  130  can at least partially extend through forefoot region  101 , midfoot region  102 , and/or heel region  103 . Knitted component  130  can also extend along lateral side  104 , medial side  105 , over forefoot region  101 , and/or around heel region  103 . In addition, knitted component  130  can at least partially define an exterior surface  119  and an opposite interior surface  115  of upper  120 . Interior surface  115  can define at least a portion of void  117  within upper  120 , and exterior surface  119  can face in an opposite direction from the interior surface  115 . 
     As will be discussed, knitted component  130  can provide the upper  120  with weight savings as compared with other conventional uppers. Additionally, in some embodiments, knitted component  130  can be configured with different zones having different characteristics. For example, one or more predetermined zones can have more stretch resistance than other zones. Also, knitted component  130  can provide the upper  120  with aesthetically pleasing features and textures. Still further, knitted component  130  can provide advantages in the manufacture of footwear  100 . Other advantages due to the knitted component  130  will be explored in detail below. 
     Knitted Component Configurations 
     In some embodiments, knitted component  130  can include a plurality of knitted subcomponents that are independently formed to each have unitary knit construction. Once formed, these knitted components of unitary knit construction can be joined together to define at least a portion of upper  120 . 
     For example, as shown in the illustrated embodiments, knitted component  130  can include a first knitted component or forward knitted component  150  and a second knitted component or heel knitted component  152  that are joined together to cooperatively define knitted component  130 . In one embodiment, forward knitted component  150 , heel knitted component  152 , and strobel  125  can be joined together to cooperatively define upper  120  as shown in  FIG. 4 . 
     For purposes of clarity, forward knitted component  150  and heel knitted component  152  are shown separated and laid substantially flat in  FIG. 6  according to exemplary embodiments. As shown, forward knitted component  150  is formed of unitary knit construction, and heel knitted component  152  is also formed of unitary knit construction. 
     As used herein, the term “unitary knit construction” means that the respective component is formed as a one-piece element through a knitting process. That is, the knitting process substantially forms the various features and structures of unitary knit construction without the need for significant additional manufacturing steps or processes. A unitary knit construction may be used to form a knitted component having structures or elements that include one or more courses of yarn or other knit material that are joined such that the structures or elements include at least one course in common (i.e., sharing a common yarn) and/or include courses that are substantially continuous between each of the structures or elements. With this arrangement, a one-piece element of unitary knit construction is provided. 
     As shown in  FIG. 6 , forward knitted component  150  can include a medial portion  202 , a lateral portion  204 , and a forward portion  200 . Boundaries of forward knitted component  150  can be defined by a first U-shaped peripheral edge  208 , a smaller second U-shaped peripheral edge  209 , a first rear edge  210  that extends transversely between edge  208  and edge  209 , and a second rear edge  212  that extends transversely between edge  208  and edge  209 . 
     Additionally, heel knitted component  152  can include an upper peripheral edge  220 , a lower peripheral edge  222 , a first side edge  224  that extends transversely between upper peripheral edge  220  and lower peripheral edge  222 , and a second side edge  226  that extends transversely between upper peripheral edge  220  and lower peripheral edge  222 . In some embodiments, edges  224 ,  226  may be at least partially angled away from each other as edges  224 ,  226  extend from upper peripheral edge  220  to lower peripheral edge  222 . 
     Forward knitted component  150  can be coupled to heel knitted component  152  to define upper  120  as shown in  FIGS. 1-4 . For example, first rear edge  210  of forward knitted component  150  can be coupled to first side edge  224  of heel knitted component  152  to define a first seam  240  of upper  120 . Also, second rear edge  212  of forward knitted component  150  can be coupled to second side edge  226  of heel knitted component  152  to define a second seam  242  of upper  120 . 
     Forward knitted component  150  can be coupled to heel knitted component  152  along seam  240  and seam  242  in any suitable fashion. For example, knitted components  150 ,  152  can be coupled at seam  240  and seam  242  via stitching, via adhesives, via fasteners, or via any other suitable attachment mechanism. 
     When assembled into upper  120 , medial portion  202  of forward knitted component  150  can define a majority of medial side  105  of upper  120 . Also, forward portion  200  can define a majority of forefoot region  101  of upper  120 . Additionally, lateral portion  204  can define a majority of lateral side  104  of upper  120 . Heel knitted component  152  can define a majority of heel region  103  of upper  120 . Also, second peripheral edge  209  and upper peripheral edge  220  can cooperate to define upper edge  132  of upper  120  as shown in  FIGS. 1-3 . Furthermore, first peripheral edge  208  and lower peripheral edge  222  can cooperate to define lower edge  160  of upper  120  as shown in  FIG. 4 . Moreover, first seam  240  can extend from upper edge  132  to lower edge  160  on medial side  105  of upper  120  as shown in  FIGS. 2, 3, and 4 . Additionally, second seam  242  can extend from upper edge  132  to lower edge  160  on lateral side  104  of upper  120  as shown in  FIGS. 1, 3, and 4 . 
     In some embodiments, forward knitted component  150  may include a plurality of zones that have one or more different physical properties. Boundaries of these zones are indicated by broken lines in the illustrated embodiments. For example, as most clearly illustrated in  FIGS. 3 and 6 , forward knitted component  150  can include a first zone  214 , a second zone  216 , and a third zone  218 . As shown in the illustrated embodiments, third zone  218  can be U-shaped and substantially centered between medial portion  202  and lateral portion  204 , adjacent second peripheral edge  209 . Accordingly, an internal boundary  163  of third zone  218  can be located approximately a uniform distance spaced apart from second peripheral edge  209  so as to be substantially concentric with second peripheral edge  209  as shown in the plan view of  FIG. 6 . Also, second zone  216  can extend forward longitudinally from third zone  218  toward forward portion  200 , and second zone  216  can include a medial branch  219  that extends between forward portion  200  and medial portion  202 . A first portion  221  of first zone  214  extends between third zone  218 , first rear edge  210 , peripheral edge  208 , and second zone  216 . A second portion  223  of first zone  214  extends between third zone  218 , second rear edge  212 , peripheral edge  208 , and second zone  216 . 
     First zone  214 , second zone  216 , and third zone  218  can have one or more different physical properties. For example, first zone  214  can have a larger degree or a larger amount of stretch resistance than second zone  216 , and second zone  216  can have a larger degree or larger amount of stretch resistance than third zone  218 . Stated differently, first zone  214  can be stiffer than second zone  216 , and second zone  216  can be stiffer than third zone  218 . Thus, third zone  218  can stretch readily to allow passage of the wearer&#39;s foot through collar  123  of upper  120 , whereas first zone  214  can be more stretch resistant such that first zone  214  provides support for the wearer&#39;s foot. Moreover, second zone  216  can be stretchable enough to allow upper  120  to comfortably conform to the wearer&#39;s foot. 
     Likewise, in some embodiments, heel knitted component  152  can include a plurality of zones that have one or more different physical properties. Boundaries of these zones are indicated by broken lines in the illustrated embodiments. For example, as most clearly illustrated in  FIG. 6 , heel knitted component  152  can include a first zone  228 , a second zone  230 , and a third zone  232 . 
     In an exemplary embodiment, one or more of the different zones  228 ,  230 ,  232  may be associated with different portions of heel knitted component  152 . By providing different portions of heel knitted component  152  with zones of varying physical properties, the fit, comfort, and/or support provided by heel knitted component to upper  120  may be varied as desired. 
     In one embodiment, third zone  232  may be provided along a peripheral edge of knitted component  152  that is associated with collar  132  and adjacent to opening  121  of upper  120 . An internal boundary  161  of third zone  232  is shown in  FIG. 6  in broken lines and partially demarcates third zone  232  from first zone  228  and partially demarcates third zone  232  from second zone  230 . As shown in  FIG. 6 , third zone  232  can have a substantially constant width and can extend along upper peripheral edge  220 . Thus, internal boundary  161  of third zone  232  can be located approximately a uniform distance spaced apart from upper peripheral edge  220  so as to be substantially concentric with upper peripheral edge  220  as shown in the plan view of  FIG. 6 . 
     In an exemplary embodiment, second zone  230  may be provided in a location along a portion of knitted component  152  that corresponds to a heel and/or Achilles tendon of a foot of a wearer. In this embodiment, second zone  230  may be located approximately in the middle of knitted component  152  along the transverse direction. By providing second zone  230  with a configuration that imparts various physical properties, the portion of knitted component  152  that corresponds to the heel and/or Achilles tendon of a foot of a wearer may have a desired fit, comfort, and/or support. 
     In different embodiments, second zone  230  may have any suitable shape. In one embodiment, second zone  230  may have a substantially symmetric geometric shape. For example, in this embodiment, second zone  230  can be polygonal. As shown in  FIG. 6 , second zone  230  can include an inverted triangular portion  231  and a diamond portion  233  that are arranged end-to-end and that extend from third zone  232  toward lower peripheral edge  222 . Second zone  230  can also be substantially symmetrical and centered with respect to axis X of upper  120 . Moreover, first zone  228  can extend between third zone  232 , first side edge  224 , lower peripheral edge  222 , second side edge  226 , and second zone  230 . 
     First zone  228 , second zone  230 , and third zone  232  can have one or more different physical properties. For example, first zone  228  can have a larger degree or larger amount of stretch resistance than second zone  230 , and second zone  230  can have a larger degree or larger amount of stretch resistance than third zone  232 . Stated differently, first zone  228  can be stiffer than second zone  230 , and second zone  230  can be stiffer than third zone  232 . 
     In some embodiments, first zone  228  of heel knitted component  152  can have similar physical properties as first zone  214  of forward knitted component  150 . Also, second zone  230  of heel knitted component  152  can have similar physical properties as second zone  216  of forward knitted component  150 . Moreover, third zone  232  of heel knitted component  152  can have similar physical properties as third zone  218  of forward knitted component  150 . Thus, for example, first zones  228 ,  214  can have substantially the same stretch resistance or stiffness, second zones  230 ,  216  can have substantially the same stretch resistance or stiffness, and third zones  232 ,  218  can have substantially the same stretch resistance or stiffness. 
     The varying stretch resistance of each zone  214 ,  216 ,  218 ,  228 ,  230 ,  232  can be achieved in various ways. For example, in some cases, each zone  214 ,  216 ,  218 ,  228 ,  230 ,  232  can have a different stitching pattern. Additionally, each zone  214 ,  216 ,  218 ,  228 ,  230 ,  232  may include different types of yarns or strands. More specifically, in one embodiment, third zones  218 ,  232  can be formed using a half-gauge knit to provide a ribbed appearance, and third zones  218 ,  232  can be formed at least partially using one or more elastic yarns, such as spandex. Second zones  216 ,  230  can be formed using a full-gauge knit and can be formed using one or more elastic yarns, such as spandex. In additional embodiments, second zones  216 ,  230  can have a mesh-type of appearance for increased breathability. Furthermore, first zones  214 ,  228  can be formed using a full-gauge knit and can include yarns made from thermoplastic polymeric material. These yarns can be less elastic than yarns included in second and third zones  216 ,  230 ,  218 ,  232 , and these yarns can partially melt and fuse to impart additional stiffness to the respective zones  214 ,  228  after heat is applied to upper  120 . It will be appreciated that these thermoplastic yarns can be absent from second and third zones  216 ,  230 ,  218 ,  232 . It will also be appreciated that the yarns of each zone  214 ,  216 ,  218 ,  228 ,  230 ,  232  can be incorporated and controlled through known intarsia knitting processes. Moreover, the zones  214 ,  216 ,  218 ,  228 ,  230 ,  232  can be formed and incorporated according to the teachings in commonly-owned U.S. patent application Ser. No. 13/691,316 to Podhajny, et al., entitled “Article of Footwear Incorporating a Knitted Component,” filed Nov. 30, 2012, which is hereby incorporated by reference in its entirety. 
     It will be appreciated that the knitted component  130  of upper  120  can provide weight savings for the article of footwear  100 . Also, the knitted component  130  can provide different physical characteristics at different zones  214 ,  216 ,  218 ,  228 ,  230 ,  232  such that upper  120  can be comfortable, can provide localized support to the wearer&#39;s foot, and can be easy to put on and remove. Moreover, the knitting processes used to produce knitted component  130  can reduce waste, can reduce manufacturing time, and/or can provide other manufacturing advantages. 
     Also, as discussed above, knitted component  130  can be formed from a plurality of subcomponents, namely, forward knitted component  150  and heel knitted component  152 . As such, properties of knitted component  130  can be highly controlled during manufacture. For example, it will be appreciated that the heel region  103  of upper  120  can be important for providing support to the wearer&#39;s heel without sliding or rubbing uncomfortably on the wearer&#39;s skin. Thus, heel knitted component  152  can include relatively stiff first zone  228  for providing suitable support. Heel knitted component  152  can also include the more elastic second zone  230 , which can be substantially centered on heel knitted component  152 , such that the second zone  230  can stretch and conform comfortably against the wearer&#39;s heel. The second zone  230  can also stretch and conform as the wearer&#39;s heel flexes during walking, running, and otherwise moves. Thus, the heel knitted component  152  can provide an important balance of stiff support and flexure such that a separate heel counter may not be necessary in the article of footwear  100 . 
     Moreover, because the forward knitted component  150  and heel knitted component  152  are separate and independent and are each of unitary knit construction, portions of upper  120  can be tailored and tuned for particular uses, for particular wearers, or for other purposes. For example, if the heel region  103  of upper  120  is to have a different desired physical property, for example to be made stiffer, then forward knitted component  150  could be joined to a different heel knitted component provided with a smaller second zone than second zone  230 . Alternatively, if heel region  103  is to be made more flexible, then forward knitted component  150  could be joined to another different heel knitted component provided with a larger second zone than second zone  230 . 
     Manufacturing of knitted components  150 ,  152  and upper  120  will now be discussed. As mentioned, knitted components  150 ,  152  can be formed to have one-piece unitary knit construction. For example, knitted components  150 ,  152  can be knit on flat knitting machines. Also, in some embodiments, heel knitted component  152  can be knit such that upper peripheral edge  220  is formed first, and additional courses can be added until lower peripheral edge  222  is formed. As such, upper peripheral edge  220  can have a neat and finished appearance, and raw lower peripheral edge  222  can be eventually covered and bound by sole structure  110 . Likewise, forward knitted component  150  can be formed such that second peripheral edge  209  is formed first, and courses can be added until first peripheral edge  208  is formed. 
     Then, knitted components  150 ,  152  can be joined at seams  240 ,  242  as discussed above. To facilitate this assembly process, heel knitted component  152  can include an indicia  254 , such as an “X” shown in  FIG. 8 , which differentiates between an interior surface  250  of heel knitted component  152  and an exterior surface  252  of heel knitted component  152 . It is noted that exterior surface  252  of heel knitted component  152 , shown in  FIG. 7 , does not include indicia  254 . Thus, even if heel knitted component  152  is substantially symmetric, the manufacturer can differentiate between interior and exterior surfaces  250 ,  252  to assist with orienting heel knitted component  152  for attachment to forward knitted component  150 . 
     It is also noted that interior surface  250  can partially define void  117  of upper  120 , and exterior surface  252  can face outwardly. Thus, indicia  254  as shown in  FIG. 8  can be less visible to the wearer or others when upper  120  is fully assembled. However, it will be appreciated that exterior surface  252  can include indicia  254  instead of interior surface  250 . Also, indicia  254  can be formed by yarns or strands included in the unitary knit construction of heel knitted component  152 , or indicia  254  can be marked separately from unitary knit construction of heel knitted component  152 . Moreover, indicia  254  can be located in any suitable location of heel knitted component  152 . For example, as shown in  FIG. 8 , indicia  254  can be substantially centered on heel knitted component  15  and may be adjacent to lower peripheral edge  222 . 
     Once knitted components  150 ,  152  are joined at seams  240 ,  242 , strobel  125  can be attached to lower edge  160  as shown in  FIG. 4 . Then, sole assembly  110  can be attached as discussed above. 
     Referring now to  FIG. 9 , an alternate embodiment of a heel knitted component  352  is illustrated according to additional teachings of the present disclosure. Heel knitted component  352  can be substantially similar to the embodiments discussed above. For example, heel knitted component  352  can include a first zone  328 , a second zone  330 , and a third zone  332  similar to the embodiments discussed above. However, heel knitted component  352  can define an internal boundary  361  demarcating third zone  332  from first zone  328  and second zone  330  that differs from the embodiments of  FIG. 7 . More specifically, while internal boundary  161  is located approximately a uniform distance from upper peripheral edge  220  in the embodiments of  FIGS. 6-8 , curvature of boundary  361  can be inverted relative to upper peripheral edge  320  such that portions of internal boundary  361  may be spaced apart from upper peripheral edge  320  by varying distances. For example, portions of internal boundary  361  disposed closer to second zone  330  may be spaced apart from upper peripheral edge  320  by a larger distance than other portions. Thus, the width of third zone  332  between upper peripheral edge  320  and internal boundary  361  can vary across third zone  332  in the plan view of  FIG. 9 . This can allow heel knitted component  352  to conform closely to the wearer&#39;s heel for added comfort and support. 
     In summary, footwear  100  can provide several advantages. Footwear  100  can be comfortable to wear. Footwear  100  can provide support to the wearer&#39;s foot. Footwear  100  can also flex with the wearer&#39;s foot and can flexibly conform to the wearer&#39;s foot. Physical properties can vary across different regions of footwear  100  to further enhance performance. 
     While various embodiments of the present disclosure have been described, the description is intended to be exemplary rather than limiting, and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the present disclosure. Accordingly, the present disclosure is not to be restricted except in light of the attached claims and their equivalents. Also, various modifications, combinations, and changes of the features described herein may be made within the scope of the attached claims.