Article of Footwear with a Midsole Structure

CROSS-REFERENCE TO RELATED APPLICATION

p-0002The present application is a divisional which claims benefit of U.S. application Ser. No. 12/577,310 filed Oct. 12, 2009, which claims priority to U.S. Application No. 61/104,508 filed Oct. 10, 2008, the contents therein are incorporated by reference.

BACKGROUND OF THE INVENTION

p-00031. Field of the Invention

p-0004The present invention relates to the field of footwear. The invention concerns, more particularly, an article of footwear having an upper and a sole structure with a segmented configuration for flexibility in selected regions and viewing structure.

p-00052. Background

p-0006Conventional articles of athletic footwear include two primary elements, an upper and a sole structure. The upper provides a covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure is secured to a lower surface of the upper and is generally positioned between the foot and the ground. In addition to attenuating ground reaction forces and absorbing energy (i.e., imparting cushioning), the sole structure may provide traction and control potentially harmful foot motion, such as over pronation. The general features and configuration of the upper and the sole structure are discussed in greater detail below.

p-0007The upper forms a void on the interior of the footwear for receiving the foot. The void has the general shape of the foot, and access to the void is provided by an ankle opening. Accordingly, the upper 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. A lacing system is often incorporated into the upper to selectively increase the size of the ankle opening and permit the wearer to modify certain dimensions of the upper, particularly girth, to accommodate feet with varying proportions. In addition, the upper may include a tongue that extends under the lacing system to enhance the comfort of the footwear, and the upper may include a heel counter to limit movement of the heel.

p-0008Various materials may be utilized in manufacturing the upper. The upper of an article of athletic footwear, for example, may be formed from multiple material layers that include an exterior layer, a middle layer, and an interior layer. The materials forming the exterior layer of the upper may be selected based upon the properties of wear-resistance, flexibility, and air-permeability, for example. With regard to the exterior layer, 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. Accordingly, various other areas of the exterior layer of the upper may be formed from a synthetic textile. The exterior layer of the upper may be formed, therefore, from numerous material elements that each impart different properties to specific areas of the upper.

p-0009A middle layer of the upper may be formed from a lightweight polymer foam material that provides cushioning and protects the foot from objects that may contact the upper. Similarly, an interior layer of the upper may be formed of a moisture-wicking textile that removes perspiration from the area immediately surrounding the foot. In some articles of athletic footwear, the various layers may be joined with an adhesive, and stitching may be utilized to join elements within a single layer or to reinforce specific areas of the upper.

p-0010The sole structure generally incorporates multiple layers that are conventionally referred to as an insole, a midsole, and an outsole. The insole is a thin, cushioning member located within the upper and adjacent the plantar (lower) surface of the foot to enhance footwear comfort. The midsole, which is traditionally attached to the upper along the entire length of the upper, forms the middle layer of the sole structure and serves a variety of purposes that include controlling foot motions and providing cushioning. The outsole forms the ground-contacting element of footwear and is usually fashioned from a durable, wear-resistant material that includes texturing to improve traction.

p-0011The primary element of a conventional midsole is a resilient, polymer foam material, such as polyurethane or ethylvinylacetate, that extends throughout the length of the footwear. The properties of the polymer foam material in the midsole are primarily dependent upon factors that include the dimensional configuration of the midsole and the specific characteristics of the material selected for the polymer foam, including the density of the polymer foam material. By varying these factors throughout the midsole, the relative stiffness, degree of ground reaction force attenuation, and energy absorption properties may be altered to meet the specific demands of the activity for which the footwear is intended to be used.

p-0012In addition to polymer foam materials, conventional midsoles may include, for example, stability devices that resist over-pronation and moderators that distribute ground reaction forces. The use of polymer foam materials in athletic footwear midsoles, while providing protection against ground reaction forces, may introduce instability that contributes to a tendency for over-pronation. Although pronation is normal, it may be a potential source of foot and leg injury, particularly if it is excessive. Stability devices are often incorporated into the polymer foam material of the midsoles to control the degree of pronation in the foot. Examples of stability devices are found in U.S. Pat. Nos. 4,255,877 to Bowerman; 4,287,675 to Norton et al.; 4,288,929 to Norton et al.; 4,354,318 to Frederick et al.; 4,364,188 to Turner et al.; 4,364,189 to Bates; and 5,247,742 to Kilgore et al. In addition to stability devices, conventional midsoles may include fluid-filled bladders, as disclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy, for example.

SUMMARY OF THE INVENTION

p-0013The present invention pertains to an article of footwear with a segmented sole structure.

p-0014In one aspect of the invention, an article of footwear includes an upper and a sole structure secured to the upper, the sole structure comprises an outsole unit and a plurality of discrete sole elements disposed within the outsole unit enabling viewing of the sole elements therein. The sole elements being separated by a plurality of flexion regions, the plurality of flexion regions including: a first flexion region in a longitudinal direction with respect to the footwear.

p-0015In another aspect, the first flexion region extends through an entire length of the sole structure. The first flexion region can be spaced inward from a lateral side of the sole structure in at least a forefoot region of the footwear. A second flexion region extends in the longitudinal direction, the second flexion region extending through a portion of the length of the sole structure and ending in a metatarsal region of the sole structure; and a plurality of third flexion regions that extend laterally from the medial side to the lateral side of the sole structure.

p-0016The advantages and features of novelty characterizing the present invention are pointed out with particularity in the appended claims. To gain an improved understanding of the advantages and features of novelty, however, reference may be made to the following descriptive matter and accompanying drawings that describe and illustrate various embodiments and concepts related to the invention.

DESCRIPTION OF THE DRAWINGS

p-0017The foregoing Summary of the Invention, as well as the following Detailed Description of the Invention, will be better understood when read in conjunction with the accompanying drawings.

p-0018<figref idrefs="DRAWINGS">FIG. 1</figref> is a lateral elevational view of an article of footwear according to the teachings of the present invention.

p-0019<figref idrefs="DRAWINGS">FIG. 2</figref> is a cross-sectional view of the article of footwear of <figref idrefs="DRAWINGS">FIG. 1</figref> along an heel-to-axis.

p-0020<figref idrefs="DRAWINGS">FIG. 3</figref> is a lateral elevational view of an outsole structure of the article of footwear of <figref idrefs="DRAWINGS">FIG. 1</figref> with the upper removed for clarity.

p-0021<figref idrefs="DRAWINGS">FIG. 4</figref> is a bottom plan view of the sole structure of the article of footwear of <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0022<figref idrefs="DRAWINGS">FIG. 5</figref> is an elevational view of an insole-midsole structure of the article of footwear of <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0023<figref idrefs="DRAWINGS">FIG. 6</figref> is a top plan view of one embodiment of an insole structure of the footwear of <figref idrefs="DRAWINGS">FIG. 1</figref>.

p-0024<figref idrefs="DRAWINGS">FIG. 7</figref> is a bottom plan view of a midsole structure of the footwear of <figref idrefs="DRAWINGS">FIG. 10</figref>.

p-0025<figref idrefs="DRAWINGS">FIG. 8</figref> is bottom plan view of a midsole structure superimposed with anatomical structure of a foot of a wearer.

p-0026<figref idrefs="DRAWINGS">FIG. 9</figref> is a bottom plan view of an alternative midsole structure.

p-0027<figref idrefs="DRAWINGS">FIG. 10</figref> is a lateral elevational view of an article of footwear with the midsole structure of <figref idrefs="DRAWINGS">FIG. 1</figref>, alternative outsole and upper structures.

p-0028<figref idrefs="DRAWINGS">FIG. 11</figref> is a bottom plan view of an alternative outsole structure for an article of footwear.

DETAILED DESCRIPTION OF THE INVENTION

p-0029The following discussion and accompanying figures disclose an article of footwear <b>10</b> in accordance with the present invention. Footwear <b>10</b> is depicted in the figures and discussed below as having a configuration that is suitable for athletic activities, particularly running. The concepts disclosed with respect to footwear <b>10</b> may, however, be applied to footwear styles that are specifically designed for a wide range of other athletic activities, including basketball, baseball, football, soccer, walking, and hiking, for example, and may also be applied to various non-athletic footwear styles. Accordingly, one skilled in the relevant art will recognize that the concepts disclosed herein may be applied to a wide range of footwear styles and are not limited to the specific embodiments discussed below and depicted in the figures.

p-0030Footwear <b>10</b> is depicted in <figref idrefs="DRAWINGS">FIGS. 1-9</figref> and includes an upper <b>20</b> and a sole structure <b>30</b>. Upper <b>20</b> is formed from various material elements that are stitched or adhesively-bonded together to form an interior void that comfortably receives a foot and secures the position of the foot relative to sole structure <b>30</b>. Sole structure <b>30</b> is secured to a lower portion of upper <b>20</b> and provides a durable, wear-resistant component for attenuating ground reaction forces and absorbing energy (i.e., providing cushioning) as footwear <b>10</b> impacts the ground.

p-0031Many conventional articles of footwear exhibit a configuration that controls the motion of the foot during running or other activities. A conventional sole structure, for example, may have a relatively stiff or inflexible construction that inhibits the natural motion of the foot. Upper <b>20</b> and sole structure <b>30</b> have a structure that cooperatively articulate, flex, stretch, or otherwise move to provide an individual with a sensation of natural, barefoot running That is, upper <b>20</b> and sole structure <b>30</b> are configured to complement the natural motion of the foot during running or other activities. In contrast with barefoot running, however, sole structure <b>30</b> attenuates ground reaction forces and absorbs energy to cushion the foot and decrease the overall stress upon the foot and provide a sense of the ground for movement to strengthen the musculoskeletal performance of a wearer, in particular the foot of a child.

p-0032For a better understanding of the article of footwear <b>10</b>, <figref idrefs="DRAWINGS">FIG. 8</figref> illustrates a bottom plan view of sole structure including a schematical representation with predetermined regions or portions substantially corresponding to the foot anatomy of a human body. For ease of explanation regarding the preferred embodiment, the skeletal structure of a human foot includes three major divisions—the forefoot, the midfoot, and the rearfoot. The forefoot includes forward phalanges interconnected to metatarsal bones. The phalanges and metatarsals bones are formed in five rows in which the medial side starts the first row across to the fifth row on the lateral side of the foot. The heads of the metatarsal bones have a generally bulbous structure that is susceptible to injury in conventional footwear. It should be recognized that the “great toe” structure is the first row, which includes two phalanges and a first metatarsal bone. The midfoot generally includes the arch formed by several interconnecting bones. Finally, the rearfoot includes the heel bone. One of ordinary skill in the art should recognize that foot anatomy also includes interconnecting muscles and other tissues, which are not shown for clarity.

p-0033For purposes of reference as shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, footwear <b>10</b> may be divided into three general regions: a forefoot region <b>11</b>, a midfoot region <b>12</b>, and a rearfoot region <b>13</b>, as defined in <figref idrefs="DRAWINGS">FIGS. 1 and 2</figref>. One of ordinary skill in the art should recognize that each region generally lies beneath the respective forefoot, midfoot, and rearfoot of a wearer when shoe <b>10</b> is properly sized. Regions <b>11</b>-<b>13</b> are not intended to demarcate precise areas of footwear <b>10</b>. Rather, regions <b>11</b>-<b>13</b> are intended to represent general areas of footwear <b>10</b> that provide a frame of reference during the following discussion. Although regions <b>11</b>-<b>13</b> apply generally to footwear <b>10</b>, references to regions <b>11</b>-<b>13</b> may also apply specifically to upper <b>20</b>, sole structure <b>30</b>, or an individual component or portion within either of upper <b>20</b> or sole structure <b>30</b>.

p-0034In forefoot region <b>32</b>, sole structure <b>30</b> is further defined by a forwardly disposed phalanx region <b>35</b>, and a rearward disposed metatarsal region <b>37</b>. Phalanx region <b>35</b> includes at least a first phalanx region <b>39</b> having a distal phalanx region <b>39</b><i>a, </i>and a proximal phalanx region <b>39</b><i>b. </i>Metatarsal region <b>37</b> includes at least—a first metatarsal region <b>40</b>. It should be appreciated that metatarsal region <b>37</b> includes a second through fifth metatarsal region corresponding the second through fifth metatarsal bones. It should be recognized that these regions correspond to the typical anatomy of a human foot, which does not deviate significantly from the norm. Sole structure <b>30</b> includes regions not specifically described as known to one of ordinary skill in the art.

p-0035The various material elements forming upper <b>20</b>, which will be described in greater detail below, combine to provide a structure having a lateral side <b>21</b>, an opposite medial side <b>22</b>, and a tongue <b>23</b> that form the void within upper <b>20</b>. Lateral side <b>21</b> extends through each of regions <b>11</b>-<b>13</b> and is generally configured to contact and cover a lateral surface of the foot. A portion of lateral side <b>21</b> extends over an instep of the foot and overlaps a lateral side of tongue <b>23</b>. Medial side <b>22</b> has a similar configuration that generally corresponds with a medial surface of the foot. A portion of medial side <b>22</b> also extends over the instep of the foot and overlaps an opposite medial side of tongue <b>23</b>. In addition, lateral side <b>21</b>, medial side <b>22</b>, and tongue <b>23</b> cooperatively form an ankle opening <b>25</b> in heel region <b>13</b> to provide the foot with access to the void within upper <b>20</b>.

p-0036Tongue <b>23</b> extends longitudinally along upper <b>20</b> and is positioned to contact the instep area of the foot. Side portions of tongue <b>23</b> are secured to an interior surface of each of lateral side <b>21</b> and medial side <b>22</b>. A lace <b>26</b> extends over tongue <b>23</b> and through apertures formed in lateral side <b>21</b> and medial side <b>22</b>. Tongue <b>23</b> extends under strap <b>26</b> to separate strap <b>26</b> from the instep area of the foot. By increasing the tension in lace <b>26</b>, the tension in lateral side <b>21</b> and medial side <b>22</b> may be increased so as to draw lateral side <b>21</b> and medial side <b>22</b> into contact with the foot. Similarly, by decreasing the tension in strap <b>26</b>, the tension in lateral side <b>21</b> and medial side <b>22</b> may be decreased so as to provide additional volume for the foot within upper <b>20</b>. This general configuration provides, therefore, a mechanism for adjusting the fit of upper <b>20</b> and accommodating various foot dimensions.

p-0037A variety of materials are suitable for upper <b>20</b>, including the materials that are conventionally utilized in footwear uppers. Accordingly, upper <b>20</b> may be formed from combinations of leather, synthetic leather, natural or synthetic textiles, polymer sheets, polymer foams, mesh textiles, felts, non-woven polymers, or rubber materials, for example. In one arrangement, the exposed portions of upper <b>20</b> may be formed from two coextensive layers of material that are stitched or adhesively bonded together. Based upon the above discussion, the various portions of upper <b>20</b> include different combinations of materials. For example, the materials forming the tongue <b>23</b> and around ankle opening <b>25</b> may be different than the materials forming the areas of lateral side <b>21</b> and medial side <b>22</b> that extend through forefoot region <b>11</b> and midfoot region <b>12</b>. In further embodiments, however, different materials may be utilized for the various areas upper <b>20</b>, or upper <b>20</b> may include more than two layers of material. In joining upper <b>20</b> and sole structure <b>30</b>, adhesives, stitching, or a combination of adhesives and stitching may be utilized. In this manner, upper <b>20</b> is secured to sole structure <b>30</b> through a substantially conventional process.

p-0038Sole structure <b>30</b> includes an insole <b>31</b>, a midsole <b>32</b>, and an outsole <b>33</b>. Outsole <b>33</b> includes a plurality of outsole elements that are formed in the lower surface of the outsole. Outsole <b>33</b> is an exterior surface of the footwear <b>10</b> to provide wear-resistance and ground-engagement. Suitable materials for outsole <b>33</b> include any of the conventional rubber materials that are utilized in footwear outsoles, such as carbon black rubber compound. Outsole structure <b>33</b> has a cupped configuration to form an internal cavity or void. Accordingly, midsole <b>32</b> is received within the cavity of the outsole structure <b>33</b> for performance benefits. Additionally, the outsole structure <b>33</b> acts as a protective cover for the midsole <b>32</b>. Outsole structure <b>33</b> provides a cupped feature at least to the connection interface between the upper <b>20</b>. In one arrangement, outsole structure <b>33</b> is constructed of a translucent or transparent material. The outsole structure <b>33</b> is substantially transparent providing clear visibility to the contents in the void of the structure <b>33</b>. In addition, the outsole material alters or enhances the coloration or tint of the midsole to accentuate look of the midsole to the wearer or other individual.

p-0039Outsole structure <b>33</b> has thickness (see <figref idrefs="DRAWINGS">FIG. 2</figref>) so as to provide for the wearer to sense the ground forces via the midsole <b>33</b>, while providing ground engagement and wear resistance. The thickness of outsole structure <b>33</b> is generally defined as the dimension that extends between inner surface and the lower surface. In one arrangement, the thickness of the outsole <b>33</b> may vary along the longitudinal length of outsole <b>33</b>. The thickness is depicted graphically in <figref idrefs="DRAWINGS">FIG. 2</figref> as thickness dimensions t<b>11</b>-t<b>13</b>. Dimension t<b>11</b>, defined in forefoot region <b>11</b>, may be approximately 2-3 millimeters and may range from 1 to 5 millimeters, for example. Dimension t<b>12</b>, provided in midfoot region <b>12</b>, may be approximately 3 millimeters and may range from 1 to 8 millimeters, for example. Similarly, dimension t<b>13</b>, provided in rearfoot region <b>13</b>, may be approximately 2-3 millimeters and may range from <b>1</b> to <b>5</b> millimeters, for example. The thickness of outsole <b>33</b> may, for example, increase in directions that extend from forefoot region <b>11</b> towards rearfoot region <b>13</b> or be the same thickness. One skilled in the relevant art will recognize, however, that a variety of thickness dimensions and variations will be suitable for outsole <b>33</b>.

p-0040In one arrangement, regions of outsole <b>33</b> that exhibit a relatively thin thickness will, in general, possess more flexibility or sensory input to the wearer than regions of outsole <b>33</b> that exhibit a greater thickness. Variations in the thickness of outsole <b>33</b> may be utilized to modify the flexibility of sole structure <b>30</b> in specific areas. For example, forefoot region <b>11</b> may be configured to have relatively high flexibility by forming outsole <b>33</b> with a lesser thickness. A relatively less flexibility may be imparted to midfoot region <b>12</b> by forming outsole <b>33</b> with a greater thickness than in the forefoot region <b>11</b>. Nevertheless, other variations of the thickness are possible.

p-0041Insole structure <b>31</b> is positioned within upper <b>20</b> in order to contact the plantar (lower) surface of the foot and enhance the comfort of footwear <b>10</b>. In one arrangement, midsole structure <b>32</b> is secured to a lower surface of insole <b>31</b> and is positioned to extend under the foot during use. Among other purposes, midsole <b>32</b> attenuates ground reaction forces and absorbs a portion of energy (i.e., imparts partial cushioning) when walking or running, for example. Suitable materials for midsole <b>32</b> are any of the conventional polymer foams that are utilized in footwear midsoles, including ethylvinylacetate and polyurethane foam. The insole structure <b>31</b> may have a stroble material sewn into the upper <b>20</b>.

p-0042A conventional footwear midsole is a unitary, polymer foam structure that extends throughout the length of the foot and may have more stiffness or inflexibility that inhibits the natural motion of the foot. In contrast with the conventional footwear midsole, midsole <b>32</b> has a distinct segmented or podded structure that imparts relatively high flexibility and movement to the foot of a wearer. The flexible structure of midsole <b>32</b> is configured to complement the natural motion of the foot during running or other activities, and may impart a feeling or sensation of barefoot running Midsole <b>32</b> attenuates ground reaction forces and absorbs energy to cushion the foot and decrease the overall stress upon the foot and allows the wearer to sense the ground.

p-0043Insole <b>31</b> an top surface <b>41</b> and an opposite lower surface <b>42</b>. In one arrangement, top surface <b>41</b> is positioned adjacent to upper <b>20</b> and may be secured directly to upper <b>20</b>, thereby providing support for the foot. Top surface <b>41</b> may be contoured to conform to the natural, anatomical shape of the foot. Accordingly, the area of top surface <b>41</b> that is positioned in rearfoot region <b>13</b> may have a greater elevation than the area of top surface <b>41</b> in forefoot region <b>11</b>. If desired, top surface <b>41</b> may form an arch support area in midfoot region <b>12</b>, and other areas of top surface <b>41</b> may be generally raised to provide a depression for receiving and seating the foot. In further embodiments, top surface <b>41</b> may have a non-contoured configuration.

p-0044Midsole <b>32</b> is formed form a plurality of individual, separate sole elements <b>60</b> that are separated by a plurality of heel-to-toe flexion lines or flexion regions <b>62</b><i>a</i>-<b>62</b><i>b </i>and medial-to-lateral flexion lines or flexion regions <b>64</b><i>a</i>-<b>64</b><i>g. </i>Sole elements <b>60</b> are discrete portions of midsole <b>32</b> that extend downward from insole <b>31</b>. In addition, sole elements <b>60</b> are secured to the insole <b>31</b> or may be formed integral with insole <b>31</b>. The shape of each sole element <b>60</b> is determined by the positions of the various flexion lines and the anatomical flexibility desired. As depicted in <figref idrefs="DRAWINGS">FIG. 7</figref>, flexion lines <b>62</b><i>a </i>and <b>62</b><i>b </i>extend in a longitudinal direction along sole structure <b>30</b>, and flexion lines <b>64</b><i>a</i>-<b>64</b><i>g </i>extend in a generally lateral direction. This positioning forms a majority of sole elements <b>60</b> to exhibit a generally square, rectangular, or trapezoidal shape. The rearmost sole elements <b>60</b> have a quarter-circular shape due to the curvature of sole structure <b>30</b> in rearfoot region <b>13</b>.

p-0045With reference to <figref idrefs="DRAWINGS">FIG. 5</figref>, the thickness of the sole elements <b>60</b> may vary in the regions <b>11</b>-<b>3</b>. Specifically, in forefoot region <b>11</b>, the thickness may be approximately 3 millimeters and may range from 1 to 4 millimeters, for example. In the midfoot region <b>12</b>, the thickness may be approximately 5 millimeters and may range from 4 to 6 millimeters, for example. Similarly, in rearfoot region <b>13</b>, the thickness may be approximately 6 millimeters and may range from 4 to 8 millimeters, for example. The thickness of the midsole <b>31</b> may, for example, increase in directions that extend from forefoot region <b>11</b> towards rearfoot region <b>13</b> or be the same thickness in one arrangement. One skilled in the relevant art will recognize, however, that a variety of thickness dimensions and variations will be suitable for midsole <b>32</b> and that the thickness may vary accordingly.

p-0046With reference to <figref idrefs="DRAWINGS">FIGS. 5</figref>, <b>7</b>, <b>8</b>, the shape of each sole element <b>60</b> can be provided by the positions of the various flexion lines <b>62</b><i>a</i>-<b>62</b><i>b </i>and <b>64</b><i>a</i>-<b>64</b><i>g </i>or spaces that extend between sole elements <b>51</b>. Midsole <b>32</b> includes a plurality of flexion lines <b>62</b><i>a</i>-<b>62</b><i>b </i>and <b>64</b><i>a</i>-<b>64</b><i>g </i>that enhance the flex properties of sole structure <b>30</b>. The positions, orientations, and width of flexion lines are selected to provide specific degrees of flexibility in selected areas and directions. That is, flexion lines of the midsole <b>32</b> may be utilized to provide the individual with a sensation of natural, barefoot running In contrast with barefoot running, however, sole structure <b>30</b> attenuates ground reaction forces and absorbs energy to cushion the foot and decrease the overall stress upon the foot.

p-0047Flexion lines <b>62</b><i>a</i>-<b>62</b><i>b </i>also increase the flexibility of sole structure <b>30</b> by forming a segmented configuration in midsole <b>32</b>. Lateral flexibility of sole structure <b>30</b> (i.e., flexibility in a direction that extends between a lateral side and a medial side) is provided by flexion lines <b>62</b><i>a </i>and <b>62</b><i>b. </i>Flexion line <b>62</b><i>a </i>extends longitudinally through all three of regions <b>11</b>-<b>13</b>. Although flexion line <b>62</b><i>a </i>may have a straight or linear configuration, it depicted as having a generally curved arrangement. In forefoot region <b>11</b> and midfoot region <b>12</b>, flexion line <b>62</b><i>a </i>is spaced inward from the lateral side of sole structure <b>30</b>, and flexion line <b>62</b><i>a </i>is centrally-located in forefoot region <b>13</b>. Flexion line <b>62</b><i>b, </i>which is disposed in forefoot region <b>11</b> and a portion of midfoot region <b>12</b>, is centrally-located and extends in a direction that is generally parallel to flexion line <b>62</b><i>a. </i>

p-0048With reference to <figref idrefs="DRAWINGS">FIGS. 7 and 8</figref>, longitudinal flexibility of sole structure <b>30</b> (i.e., flexibility in a direction that extends between regions <b>11</b> and <b>13</b>) is provided by flexion lines <b>64</b><i>a</i>-<b>64</b><i>g. </i>Flexion lines <b>64</b><i>a</i>-<b>64</b><i>e </i>are positioned in forefoot region <b>11</b>. Flexion line <b>64</b><i>e </i>generally extends along the bone-muscle joint between forefoot region <b>11</b> and midfoot region <b>12</b>. Flexion line <b>64</b><i>f </i>generally extends along the muscle joint between midfoot region <b>12</b> and rearfoot region <b>13</b>, and flexion line <b>64</b><i>g </i>is positioned in rearfoot region <b>13</b>. Flexion lines <b>64</b><i>a</i>-<b>64</b><i>e </i>are generally parallel to each and extend in a medial-lateral direction.

p-0049The positions and orientations of flexion lines <b>64</b><i>a</i>-<b>64</b><i>g </i>are selected to complement the natural motion of the foot during the running cycle. In general, the motion of the foot during running proceeds as follows: Initially, the heel strikes the ground, followed by the ball of the foot. As the heel leaves the ground, the foot rolls forward so that the toes make contact, and finally the entire foot leaves the ground to begin another cycle. During the time that the foot is in contact with the ground, the foot typically rolls from the outside or lateral side to the inside or medial side, a process called pronation. That is, normally, the outside of the heel strikes first and the toes on the inside of the foot leave the ground last. Flexion lines <b>64</b><i>a</i>-<b>64</b><i>g </i>promotes a neutral foot-strike position and complements the neutral forward roll of the foot as it is in contact with the ground. Flexion lines <b>62</b><i>a </i>and <b>62</b><i>b </i>provide lateral flexibility to permit the foot to pronate naturally during the running cycle.

p-0050The conventional sole structure, as discussed above, may have a relatively stiff or inflexible construction that inhibits the natural motion of the foot. For example, the foot may attempt to flex during the stage of the running cycle when the heel leaves the ground. The combination of the inflexible midsole construction and a conventional heel counter operates to resist flex in the foot.

p-0051The overall flexibility of sole structure <b>30</b> may be enhanced through the configuration of outsole <b>33</b>. With reference to <figref idrefs="DRAWINGS">FIG. 4</figref>, a lower surface of outsole <b>33</b> is depicted as having a plurality of grooves <b>33</b><i>a</i>-<b>33</b><i>b </i>and grooves <b>34</b><i>a</i>-<b>34</b><i>g </i>that generally correspond with the positions and configuration of midsole flexion lines <b>62</b><i>a</i>-<b>62</b><i>b </i>and <b>64</b><i>a</i>-<b>64</b><i>g</i>, respectively. Groove <b>33</b><i>a </i>extends longitudinally through substantially the entire length of outsole <b>33</b> and generally corresponds with the position of flexion line <b>62</b><i>a. </i>Groove <b>33</b><i>b </i>extends longitudinally through a portion of the length of outsole <b>33</b> and generally corresponds with the position of midsole flexion line <b>62</b><i>b. </i>Similarly, grooves <b>34</b><i>a</i>-<b>34</b><i>g </i>extend laterally from a medial side to a lateral side of outsole <b>33</b> and generally correspond with the positions of midsole flexion lines <b>64</b><i>a</i>-<b>64</b><i>g. </i>This configuration provides additional flexibility to sole structure <b>30</b> and enhances the segmented configuration. A similar configuration is depicted in <figref idrefs="DRAWINGS">FIGS. 9-11</figref>, a lower surface of outsole <b>33</b>′ is depicted as having a plurality of grooves <b>33</b><i>a</i>″-<b>33</b><i>b</i>″ and grooves <b>34</b><i>a</i>″-<b>34</b><i>g</i>″ that generally correspond with the positions and configuration of midsole flexion lines <b>62</b><i>a</i>′ and <b>62</b><i>b</i>′ and <b>64</b><i>b</i>′-<b>64</b><i>g</i>′ of midsole <b>32</b>′. With reference to <figref idrefs="DRAWINGS">FIG. 6</figref>, insole <b>31</b>′ may be a plurality of apertures <b>70</b> therein for mounting of the sole elements <b>60</b> at the specific locations.

p-0052The present invention is disclosed above and in the accompanying drawings with reference to a variety of embodiments. The purpose served by the disclosure, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the embodiments described above without departing from the scope of the present invention, as defined by the appended claims.