DE68929355T2 - Rounded midsole side with greater strength - Google Patents

Abstract

A construction for a shoe (20), particularly an athletic shoe such as a running shoe, includes a sole (28) provided with at least one bulge having concavely rounded inner and outer surfaces (30, 31). The bulge may be located on a side of the shoe sole (28) at a location which substantially corresponds to the location of one of the essential structural support and propulsion elements of an intended wearer's foot when inside the shoe. The thickness of the bulge decreases gradually in at least one of an anterior or posterior direction to a lesser thickness, as viewed in a horizontal plane when the shoe sole (28) is in an upright, unloaded condition.

Description

Background of the invention

The invention relates to a shoe, such as a street shoe, a sports shoe, and in particular to a running shoe having a contoured sole. More particularly, this invention relates to a novel design of a contoured sole for a running shoe which improves its inherent stability and effective movement of the shod foot under extreme loading. Even more particularly, this invention relates to a running shoe wherein the shoe sole conforms to the natural shape of the foot, particularly its sides, allowing the shoe to react naturally with the ground as it would if the foot were bare, while still protecting and cushioning the foot.

For the purposes of introduction, it is very rare for barefoot runners to incur "overuse" injuries despite very high activity levels. In contrast, such injuries are very common for runners in shoes, even for activity levels well below "overuse." Consequently, a persistent problem for runners in shoes is to reduce or eliminate such injuries and to improve cushioning and protection for the foot. A novel proposed solution according to this invention with an improved shoe is primarily directed toward understanding the causes of such problems.

There are a wide variety of running shoe designs available that are intended to provide stability but result in a restriction in the natural effective movement of the foot and ankle. However, designs that provide free, flexible movement rather than a lack of control or stability. A popular existing shoe design consists of an inward-turned, outward-turned sole, with the bottom surface wider than the heel-engaging portion. However, such shoes are unstable in extreme situations because when the sole is inward-turned or on edge, it is immediately supported only by the sharp edge of the sole where the entire weight of the body, multiplied by a factor of approximately three at peak running, is concentrated. Since an unnatural lever arm and moment of force are created under such conditions, the foot and ankle are destabilized and in extreme cases, beyond a certain pivot point about the articulation point of the edge of the sole, inevitably cause ankle strain. In contrast, the bare foot is always in stable equilibrium without a comparable lever arm or moment of force, and the bearing base of the bare ankle broadens substantially inward at the maximum range of its rotation, approximately 20º, when the heel bone comes into contact with the ground. This is in contrast to the underside of the conventionally available shoe sole, which maintains a sharp unstable edge.

Existing running shoes disrupt the natural foot and ankle biomechanics, destroying natural stability and effective natural movement. They do this because the natural position of the foot relative to the ground is altered during the weight-bearing phase of running or walking. The foot, in its natural, bare state, is in direct contact with the ground, so its relative distance from the ground is apparently constant at zero. Even when the foot naturally tilts from side to side, either moderately during running or extremely during a stumble or misstep, the distance always remains constant at zero.

In contrast, existing shoes maintain a constant distance from the ground - the thickness of the shoe sole - only when they are perfectly flat on the ground. As soon as the shoe is tilted, the distance between the foot and the ground begins to change in an unnatural way as the shoe sole pivots around the outer edge. In conventional sports shoes the gap most typically increases and then decreases due to the raised sides; many street shoes with a relatively wide heel follow this pattern, although some with narrower heels only decrease. In all existing shoes, the gap decreases over the entire range when tilted 90 degrees to zero, leading to ankle sprains and fractures.

However, a corrected shoe sole design avoids such an unnatural interference by neutrally maintaining a constant distance between the foot and the ground even when the shoe is tilted sideways, as if in reality a sole were only there to cushion and protect. Unlike existing shoes, the corrected shoe would move with the natural sideways inward and outward turning movement of the foot. There are two possible geometric solutions to the problem of using a shoe sole to maintain a natural constant distance during that sideways movement, depending on whether only the lower horizontal plane of the shoe sole surface changes to achieve a natural contour or whether both the upper and lower surface planes change.

In the two-plane solution, the naturally contoured design described in Figs. 1 to 28 changes both the upper and lower sides or planes of the shoe sole to match the natural contour of the human foot. The two-plane solution is the most basic concept and of course the most effective. It is the only true geometric solution to the mathematical problem of maintaining a constant distance between the foot and the ground and the optimal one in the sense that round is the only shape for a wheel and perfectly round is the optimal one. On the other hand, it is the least similar to existing designs of the two possible solutions and requires computer-aided design and computer-aided injection molding manufacturing techniques.

In the more conventional one-plane solution, the quadrant contour side design described in Figs. 29 to 37, the side contours are defined by changes in the bottom surface alone. The top surface or plane of the shoe sole remains unchanged flat in front plane cross sections, as in most existing shoes, while the plane of the bottom shoe sole is variable at the sides to provide a contour that maintains natural foot and joint biomechanics. Although the single plane quadrant contour side design is less optimal than the two plane solution, it is the only optimal single plane solution to the problem of avoiding disruption of natural human biomechanics. The single plane solution is closest to existing shoe sole designs and is therefore the easiest and cheapest to manufacture with conventional equipment. The single plane quadrant contour side design is preferred for dress or street shoes and for light loads such as walking because it is more conventional in appearance than the two plane solution, but also less biomechanically effective.

It is therefore an overall object of this invention to provide a novel shoe design which approximates the bare foot. It has been found by examining the most extreme range of ankle motion up to near the point of ankle sprain that the abnormal motion of an ankle sprain in inversion, which is a tipping outward or outward rotation of the foot, is accurately simulated when stationary. With this observation, it can be seen that the extreme range stability of the conventionally shod foot is significantly less than that of the bare foot and that the shoe itself creates a gross instability which would not otherwise exist.

Even more importantly, a normal barefoot running motion, which consists of approximately 7º of inward rotation and 7º of outward rotation, does not occur in the shod foot, where 30º of inward rotation and 30º of outward rotation are common. Such a normal barefoot motion is geometrically unattainable because the average running shoe heel is approximately 60% wider than the width of the human heel. The result is that the shoe heel and the human heel cannot rotate together naturally; rather, the human heel must rotate within the shoe, but this rotation is counteracted by the heel reinforcement of the shoe, the motion control features and the lacing and tying of the shoe at the top and also by the various types of anatomical supports within the shoe.

Consequently, it is an overall objective to provide an improved shoe design that does not build on the current contradiction inherent in current shoe designs that make the goals of stability and effective natural movement incompatible and even mutually exclusive. It is a further overall objective of the invention to provide a new contour design that simulates the natural barefoot movement when running and thus avoids the contradictions inherent in previous designs.

It is a further object of this invention to provide a running shoe which overcomes the problem of the known prior art.

It is a further object of this invention to provide a shoe in which the outer extent of the raised part of the sole includes all the support structures of the foot, but does not extend further than the outer edge of the flat part of the sole of the foot, so that the outline of the horizontal plane of the top of the flat part of the shoe sole coincides as closely as possible with the load-bearing part of the sole of the foot.

It is a further object of the invention to provide a shoe having a sole with a side contoured to and conforming to the natural shape of the side or edge of the human foot.

It is a further object of this invention to provide a novel shoe structure in which the contoured sole has a shoe sole thickness which is exactly constant at both side panels and contoured panels as measured in frontal plane cross sections and thus biomechanically neutral even when the shoe is tilted to either side, forward or backward.

It is a further object of this invention to provide a shoe in which a sole is completely contoured like and consistent with the natural shape of the unloaded human foot and which flattens under load in exactly the same way as the foot does.

It is yet another object of this invention to provide a new stable shoe design in which the rise or wedge of the heel increases or the taper of the toe decreases in the sagittal plane of the shoe sole thickness so that the sides of the shoe sole which naturally coincide with the sides of the foot also increase or decrease by exactly the same amount so that the thickness of the shoe sole in a frontal plane cross section is always constant.

It is a further object of this invention to provide a shoe having a sole having a naturally contoured design as described herein, wherein the sides of the shoe are shortened to essential structural support and propulsion elements to provide flexibility and wherein the shoe sole can be increased in size to compensate for the increased loading.

It is a further object of this invention to provide a sole design having a plurality of freely articulated essential structural support elements in the sole of the shoe which are mated with the sole of the foot and are freely movable independently of one another to follow the movement of the freely articulated bony structures of the foot.

It is yet another object of this invention to provide a shoe of the type described in which the material of the sole is removed except under essential structural support elements of the foot.

It is yet another object of this invention to provide a shoe of the type described with treads having an outer or base surface which follows the theoretically ideal stability plane.

It is yet another overall object of this invention to provide a shoe construction which has a shape defined by the natural shape of an unloaded foot and which deforms under load so that it loaded foot and which deforms under load so that it at least approaches the theoretical stability level.

It is yet another object of this invention to provide a shoe construction in which a graphical representation of the range of inward and outward rotational movement defines a curve with substantially no change in the vertical component over a range of at least 40 degrees.

It is yet another object of this invention to provide a shoe having a sole edge surface terminating in a laterally extending portion made of a flexible material and structured to terminate after loading in a position approximating or parallel to the theoretically ideal stability plane.

It is yet another object of this invention to provide a shoe having a plurality of frontal plane slots arranged at predetermined locations in the shoe sole.

It is yet another object of this invention to provide a proper method for measuring the thickness of shoe sole contours.

It is still a further object of the invention to provide a shoe having a rounded sole edge contoured like the natural shape of the side or edge of the human foot, but in a geometrically precise manner so that the shoe sole thickness is exactly constant even when the shoe sole is tilted to either side, forward or backward.

It is a further object of this invention to provide a novel shoe structure in which the contoured sole has a contoured surface at the outer edge portions described by a radius equal to the thickness of the shoe sole with a center of rotation at the outer edge of the top of the shoe sole.

It is a further object of this invention to provide a sole structure of the type described having at least portions of outer edge quadrants, the outer edge of each quadrant coinciding with the horizontal plane of the upper surface of the sole when the outer edge is perpendicular thereto.

It is yet another object of this invention to provide a shoe sole of the type described, wherein the bottom or outsole of the shoe has most or all of the special contours of the new design, while other parts of the shoe, such as the insole and heel riser, are made in a conventional manner.

It is yet another object of this invention to provide a shoe of the type described which has further improvements incorporated in the structure which defines the theoretically ideal stability plane.

It is yet another object of this invention to provide a shoe of the type described in which the improvements contained in the structure defining the theoretically ideal stability plane are applied to the two-plane embodiments of the invention as described herein.

These and other objects of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Short description of the drawings

The drawings show in

Fig. 1 is a perspective view of a typical running shoe known in the prior art to which the invention can be applied;

Fig. 2 in Fig. 2A and 2B the hindered natural movement of the shoe heel in a frontal plane cross-section when turning inwards and outwards, whereby the shoe sole has a raised bottom as in a conventional design of the known prior art, as in Fig. 1, and in Figs. 2C and 2D the effective movement of a narrow rectangular shoe sole design;

Fig. 3 is a frontal plane cross-section showing a shoe sole of uniform thickness which conforms to the natural shape of the human foot and the novel shoe design according to the invention;

Fig. 4 in Figs. 4A - 4D the load-bearing flat component of a shoe sole and a naturally contoured stability side component and also a preferred horizontal perimeter of the flat, load-bearing part of the shoe sole when the sole of the invention is used;

Fig. 5 is a schematic sketch showing in Figs. 5A and 5B the novel contoured side sole design according to the invention with variable heel elevation;

Fig. 6 is a side view of the novel stable contoured shoe according to the invention showing the contoured side design;

Fig. 7D is a plan view of the shoe sole shown in Fig. 6, wherein Fig. 7A is a sectional view of the forefoot portion along lines 7A of Fig. 6 or Fig. 7; Fig. 7B is a section along lines 7B of Figs. 6 and 7; and Fig. 7C is a sectional view along the heel along lines 7C in Figs. 6 and 7;

Fig. 8 is a drawn comparison between a conventional raised shoe sole of the known prior art and the contoured sole design according to the invention;

Fig. 9 in Figs. 9A - 9C the extremely stable conditions for the novel shoe sole according to the invention in its neutral and extreme situations;

Fig. 10 is a side sectional view of the naturally contoured sole side, showing in Fig. 10A how the sole maintains a constant distance from the floor during rotation of the shoe edge; and showing in Fig. 10B how a conventional The sole of the shoe cannot maintain a constant distance from the floor;

Fig. 11 in Figs. 11A - 11E a plurality of side cross sections in the sagittal plane showing examples of thickness changes of the conventional sole to which the invention can be applied;

Fig. 12 in Figs. 12A - 12D are sectional views in the frontal plane of the shoe sole according to the invention, showing a theoretically ideal stability plane and blunting of the sole side contour to reduce the shoe volume;

Fig. 13 in Figs. 13A - 13C the contoured sole design according to the invention applied to various tread and Velcro patterns;

Fig. 14 shows, in a rear view, an application of the sole according to the invention to a shoe in order to provide an aesthetically pleasing and functionally effective design;

Fig. 15 a fully contoured sole design that follows the natural contour of the bottom and also the sides of the foot;

Fig. 16 is a schematic frontal plane sectional view of static forces acting on the ankle joint and their position relative to the shoe sole according to the invention during normal and extreme inward and outward rotational movement;

Fig. 17 is a schematic front plane view of a plurality of motion magnitude curves of the center of mass for various degrees of inward rotation for the shoe sole according to the invention in contrast to the movements shown in Fig. 2;

Fig. 18 in Figs. 18A and 18B a schematic view of a human heel from behind in relation to a conventional shoe sole (Fig. 18A) and to the sole of the invention (Fig. 18B);

Fig. 19 the naturally contoured side design extended to the other natural contours under the load-bearing foot, such as the main longitudinal curvature;

Fig. 20 the fully contoured shoe sole design, extended to the bottom of the entire unloaded foot;

Fig. 21 the fully contoured shoe sole design, shortened along the sides to only essential structural support and forward movement elements;

Fig. 22 illustrates the application of the invention to provide a street shoe having a properly contoured sole in accordance with the invention and side edges perpendicular to the floor as is typical of a street shoe;

Fig. 23 a method for producing the theoretically ideal stability plane using a plumb-tangent method;

Fig. 24 a circle radius method for producing the theoretically ideal stability plane;

Fig. 25 an alternative embodiment of the invention, wherein the sole structure changes in use to follow a theoretically ideal stability plane according to the invention during deformation;

Fig. 26 an embodiment in which the contour of the sole according to the invention is approximated by a plurality of line segments;

Fig. 27 an embodiment in which the stability sides are geometrically determined as a section of a ring;

Fig. 28 a shoe sole design which enables unrestricted inward/outward rotational movement by providing torsional flexibility in the instep area of the shoe sole;

Fig. 29 is a diagram showing in Figs. 29A-29C the outer contoured sides relative to the sole of the novel shoe design according to the invention;

Fig. 30 is a schematic study showing the novel contoured side sole design according to the invention with variable heel elevation in Figs. 30A and 30B;

Fig. 31 is a side cross-sectional view of the quadrant sole side showing how the sole maintains a constant distance from the floor during rotation of the shoe edge;

Fig. 32 in Figs. 32A - 32C are frontal plane cross-sectional views of the inventive shoe sole showing a theoretically ideal stability plane and stumps of the sole edge quadrant to reduce the bulk of the shoe;

Fig. 33 in Figs. 33A-33C are heel cross-sectional views of a conventional street shoe (Fig. 33A) and the application of the invention shown in Fig. 33B to provide a street shoe (Fig. 33C) with a properly contoured sole according to the invention;

Fig. 34 is a schematic rear view showing a relationship between the heel bones of the foot and the use of a wedge in the shoe according to the invention;

Fig. 35 an alternate embodiment of the invention, wherein the sole structure deforms in use to follow a theoretically ideal stability plane according to the invention during deformation;

Fig. 36 an embodiment in which the sole contour according to the invention is approximated by a plurality of tendon segments;

Fig. 37 is a schematic view of the theoretically ideal stability plane;

Fig. 38 various designs, with the outsole having most or all of the special contours of the new design and containing a flat surface;

Fig. 39 in Figs. 39A - 39C frontal plane cross sections of an improvement of the previously described embodiment;

Fig. 40 in Fig. 40A - 40C the improvement of Fig. 39 applied to the naturally contoured side embodiment of the invention.

Detailed description of the preferred embodiment

In addition to the various embodiments disclosed in the description below, the present invention claimed herein relates to a particular embodiment of the contoured shoe sole design shown in Figure 38A and illustrated in Figures 11A-11E, 19A-19F, 20A-20E and 21 of the description.

In Fig. 1, there is shown a perspective view of an athletic shoe, such as a typical running shoe, according to the known art, wherein a running shoe 20 has an upper portion 21 and a sole 22. Typically, such a sole has a truncated outwardly swept construction of the type best seen in Fig. 2, with the lower portion 22a of the sole heel being significantly wider than the upper portion 22b where the sole 22 joins the upper 21. A number of alternative sole designs are known in the art, including the design shown in U.S. Patent No. 4,449,306 to Cavanagh, in which an outer portion of the sole of the running shoe has a rounded portion having a radius of curvature of approximately 20 mm. The rounded portion is located along approximately the rear half of the length of the outer surface of the insole and heel edge areas, with the remainder of the edge area, except for a transition zone, being provided with a conventional pull-up. U.S. Patent No. 4,557,059 to Misevich also shows an athletic shoe having a contoured sole bottom in the area of first foot strike in a shoe that otherwise has an inwardly turned pull-up sole.

In such prior art designs, and particularly in athletic and running shoes, the typical design attempts to achieve stability by raising the heel, as shown in Figs. 2A and 2B, to a width of, for example, 3 to 3 1/2 inches for the lower outsole 22a of the average man's shoe size (10D). On the other hand, the width of the corresponding impression of the heel of the foot housed in the upper 21 is only about 2.25 inches for the average foot. Therefore, a misfit occurs in that the heel is locked by the mold into a rigid shoe heel pad which supports the human heel by holding it in place, which may be further enhanced by control means to stabilize the heel. Thus, in a natural movement as shown in Figs. 2A and 2B, the human heel would move within a normal range of motion of about 15º, but as shown in Figs. 2A and 2B, the human heel can only pivot within the shoe and is resisted by the shoe. Thus, Fig. 2A illustrates the impossibility of pivoting about the central edge of the human heel, as would be conventional for a barefoot bearing, about a point 23 defined by a line 23a perpendicular to the heel which intersects the lower edge of upper 21 at a point 24. The lever arm moment of force of the flared sole has a maximum at 0º and is only slightly less for a normal movement inward or outward of 7º and thus presents a strong resistance to such movement as illustrated in Figs. 2A and 2B. In Fig. 2A, the outer edge of the heel must compress to accommodate such movement. Fig. 2B illustrates that the normal natural movement of the shoe is ineffective in that the center of mass of the shoe and the shod foot are pushed upward, as discussed later in connection with Fig. 17.

A narrow rectangular shoe sole design with a heel width approaching the width of the human heel is also known and is shown in Fig. 2C and 2D. It is apparently more effective than the conventional raised sole shown in Fig. 2A and 2B. Now that the sole width is the same as the human sole width, the shoe can pivot naturally with the normal inward/outward turning motion of the walking bare foot of 7º. With such a design, the lever arm length and the vertical movement of the center of mass are approximately half that of the raised sole in a normal 7º in/out walking motion. However, the narrow rectangular shoe design with the human heel width is extremely unstable and is therefore susceptible to ankle distortion, so it has not been well received. Consequently, none of these wide or narrow designs is satisfactory.

Fig. 3 shows in a frontal plane cross-section at the heel (mid-ankle) the general concept of Applicant's design: a shoe sole 28 that conforms to the natural shape of the human foot 27 and that has a constant thickness in frontal plane cross-sections. The surface 29 of the bottom and sides of the foot 27 should exactly correspond to the top 30 of the shoe sole 28. The shoe sole thickness is defined as the shortest distance (s) between any point on the top 30 of the shoe sole 28 and the bottom 31 (Figs. 23 and 24 discuss the measurement methods more fully). In fact, Applicant's general concept is a shoe sole 28 that wraps around and conforms to the natural contours of the foot 27, as if the shoe sole 28 were made from a theoretical single flat sole layer of a constant thickness sole material that is wrapped around without any distortion or deformation of that layer as it is bent to the contours of the foot. To overcome the real-world deformation problems associated with such bending or wrapping around contours, the actual manufacture of the uniform thickness shoe sole contours preferably involves the use of multi-layer lamination or injection molding techniques.

4A, 4B and 4C illustrate in frontal plane section a significant element of Applicant's shoe design in its use of naturally contoured stabilizing sides 28a on the outer edge 28b of a shoe sole 28, generally illustrated at reference numeral 28. It is therefore a key feature of Applicant's invention to eliminate the unnatural sharp bottom edge, particularly of high-top shoes, in favor of a naturally contoured shoe sole outer side 31, as shown in Fig. 3. The side or inner edge 30a of the shoe sole stability side 28a is shaped like the natural shape on the side or edge of the human foot, as is the outer side 31a of the plantar stability side 28a, to follow a theoretically ideal stability plane. According to the invention, the thickness (s) of the shoe sole 28 is kept exactly constant even when the shoe sole is tilted to one side, forward or backward. Consequently, the naturally contoured stabilizing sides 28a according to Applicant's invention are defined to have the same thickness as the thickness 33 of the shoe sole 28 so that in cross section the shoe sole consists of a stable shoe sole 28 having at its outer edge naturally contoured stabilizing sides 28a with a surface or outer edge 31a which form part of a theoretically ideal stability plane and are described by naturally contoured sides equal to the thickness (s) of the sole 28. The top of the shoe sole 30b coincides with the loaded footprint of the wearer of the shoe, since in the case shown the foot is assumed to be loaded and therefore flat along the floor. An upper edge 32 of the naturally contoured stability side 28a may lie at any point along the contoured side 29 of the foot, while the inner edge 33 of the naturally contoured side 28a coincides with the vertical sides 34 of the loaded shoe sole 28. In practice, the shoe sole 28 is preferably formed in one piece from the parts 28b and 28a. Thus, the theoretically ideal stability plane includes the contours 31a which merge with the bottom 31b of the sole 28.

Preferably, the peripheral extent 36 of the loaded portion of the sole 28b of the shoe includes all of the support structures of the foot, but does not extend beyond the outer edge of the sole of the foot as defined by a loaded footprint as shown in Fig. 4D, which is a top view of the upper shoe sole surface 30b. Fig. 4D thus illustrates a foot outline at numeral 37 and a recommended sole outline 36 relative thereto. Consequently, an outline in the horizontal plane of the upper portion of the loaded portion of the shoe sole should therefore, excluding the contoured stability sides, preferably coincide as closely as practicable with the loaded portion of the sole of the foot with which it comes into contact. Such a horizontal outline should, as best seen in Figs. 4D and 7D, remain uniform throughout the thickness of the shoe sole and eliminate negative or positive pull-up of the sole so that the sides are exactly perpendicular to the horizontal plane, as shown in Fig. 4B. Preferably, the density of the shoe sole material is uniform.

Another significant feature of Applicant's invention is illustrated schematically in Fig. 5. Preferably, as the heel riser or heel wedge 38 having a thickness (s1) increases the total thickness (s + sl) of the combined insole and outsole 39 having a thickness of (s) toward the rear of the shoe, the naturally contoured sides 28a increase in thickness by exactly the same amount in accordance with the principles discussed in connection with Fig. 4. Thus, according to Applicant's design, the thickness of the inner edge 33 of the naturally contoured side is always equal to the constant thickness of the loaded shoe sole 28b in the frontal cross-sectional plane.

As shown in Fig. 5B, for a shoe that follows a more conventional horizontal plane contour, the sole according to Applicant's invention can be significantly improved by adding a naturally contoured side 28a which varies accordingly with the thickness of the shoe sole and which varies in the frontal plane according to the heel rise 38 of the shoe. Thus, as illustrated in Fig. 5B, the thickness of the naturally contoured side 28a in the heel cross-section is equal to the thickness (s + s1) of the shoe sole 28, which is thicker than the thickness (s) of the shoe sole 39 by an amount equivalent to the thickness of the heel rise (s1). Thus, in the generalized case, the thickness (s) of the contoured side is always equal to the thickness (s) of the shoe sole.

Fig. 6 illustrates a side sectional view of the shoe to which the invention has been applied, and this is also shown in a top plan view in Fig. 7. Thus, Figs. 7A, 7B and 7C represent frontal plane cross sections along the forefoot, at the base of the fifth metatarsal and at the heel, thereby illustrating that the shoe sole thickness is constant in each frontal plane cross section even though that thickness changes from front to back due to the heel riser 38 as shown in Fig. 6, and that the thickness of the naturally contoured sides is equal to the sole thickness in each cross section of Figs. 7A-7C. Moreover, in Fig. 7D, an overview of the left foot in a horizontal plane, it can be seen that the contour the sole follows the preferred principle of adaptation to the loaded sole imprint as shown in Fig. 4D as closely as practically possible.

Fig. 3 thus contrasts, in frontal plane cross-section, the conventional raised sole 22 shown in dashed outline and illustrated in Fig. 2 with the contoured sole 28 according to the invention as shown in Figs. 3-7.

Fig. 9 is useful for analyzing the shoe sole design according to Applicant's invention by contrasting the neutral situation shown in Fig. 9A with the extreme situations shown in Figs. 9B and 9C. Unlike the sharp sole edge of a conventional sole as shown in Fig. 2, the effect of Applicant's invention, which has a naturally contoured side 28a, is completely neutral, allowing the foot to react naturally with the ground 43, either turning inward or turning outward. This occurs in part because of the unchanging thickness along the sole edge, which keeps the sole of the foot equidistant from the ground in a preferred case. Furthermore, because the shape of the edge 31a of the contoured shoe side 28a exactly matches the edge of the foot, the shoe is enabled to react naturally with the ground in a manner that simulates the foot as closely as possible. Thus, in the neutral position shown in Fig. 9, any point 40 closest to the ground on the side of the shoe sole 30b is a distance (s) from the ground surface 43. That distance (s) remains constant even for extreme situations, as seen in Figs. 9B and 9C.

A key point of Applicant's invention is, as illustrated in Figs. 9B and 9C, that the design shown is stable in an extreme situation. The theoretically ideal stability plane is where the stability plane is defined as the sole thickness which is constant among all load-bearing points of the sole of the foot for any amount of rotation of the sole from 0º to 90º to either side or forward or backward. In other words, the foot remains stable as shown in Fig. 9 when tilted from 0º to 90º to either side or from 0º to 90º to either side, representing a bending of the foot from 0º to 90º to the back or a bending of the foot from 0º to 90º to the sole, because the sole thickness (s) between the foot and the ground always remains constant because of the precisely contoured sides. By maintaining a constant distance from the ground, the stable shoe allows the foot to react to the ground as if the foot were bare, while allowing the foot to be protected and cushioned by the shoe. In their preferred embodiment, the naturally contoured sides will effectively position and hold the foot on the loaded footprint of the shoe sole, reducing or eliminating the need for heel reinforcements and other relatively rigid control devices.

Fig. 10A illustrates how the inner edge 30a of the naturally contoured sole side 28a is maintained at a constant distance (s) from the ground over various degrees of rotation of the edge 31a of the shoe sole, as shown in Fig. 9. Fig. 10B shows how a conventional shoe sole pivots about its lower edge 42, which is its center of rotation, rather than about its upper edge, which as a result is not maintained at a constant distance (s) from the ground as in the invention, but is lowered to 0.7 (s) at 45° rotation and to zero at 90° rotation.

Fig. 11 shows typical conventional shoe sole thickness changes in the sagittal plane, such as heel risers or wedges 38 or a toe taper 38a or full sole taper 38b in Figs. 11A-11E and how the naturally contoured sides 28a are the same and thus change with those changing thicknesses as discussed in connection with Fig. 5.

Fig. 12 illustrates an embodiment of the invention which utilizes varying portions of the theoretically ideal stability plane 51 at the naturally contoured sides 28a to reduce the weight and bulk of the sole while accepting a loss of some stability of the shoe. Thus, Fig. 12A illustrates the preferred embodiment as discussed in connection with Fig. 5, wherein the outer edge 31a of the naturally contoured sides 28a follows a theoretically ideal stability plane 51. As in Figs. 3 and 4, the contoured surfaces 31a and the bottom of the sole 31b lie along the theoretically ideal stability plane 51. The theoretically ideal stability plane 51 is defined as the plane of the side 31 of the bottom of the shoe sole 31, the shoe sole conforming to the natural shape of the foot, particularly the sides, and having a constant thickness in frontal plane cross sections. As shown in Fig. 12B, a technical compromise results in a shortcut within the theoretically ideal stability plane 51 by forming a naturally contoured side surface 53a which approaches the natural contour of the foot (or more geometrically regular, which is less preferred) at an angle relative to the upper plane of the shoe sole 28, so that only a minor portion of the contoured side 28a defined by the constant thickness, which lies along the surface 31a, is coplanar with the theoretically ideal stability plane 51. Figs. 12C and 12D show similar embodiments in which the technical compromise shown results in increasingly smaller portions of the contoured side 28a which lie along the theoretically ideal stability plane 51. The part of the surface 31a merges into the upper side 53a of the naturally contoured side.

The embodiment of Fig. 12 may be desirable for parts of the shoe sole that are less frequently used so that the additional part of the side is used less frequently. For example, a shoe can typically roll sideways in an inward turn up to about 20º on the order of 100 times for each time it rolls out to 40º. For a basketball shoe shown in Fig. 12B, the additional stability is needed. Nevertheless, the additional shoe weight to cover that infrequently encountered range of motion is approximately equivalent to covering the frequently encountered range. Now, since in a racing shoe this weight may not be desirable, a compromise engineering solution of the type shown in Fig. 12D is possible. A typical running/jogging shoe is shown in Fig. 12C. The range of possible variations is unlimited here.

Fig. 13 shows the theoretically ideal stability plane 51 in defining embodiments of the shoe sole having different tread or velcro patterns. Thus, Fig. 13 illustrates that the invention is applicable to shoe soles having conventional ground tread patterns. Accordingly, Fig. 13A is similar to Fig. 12B, but also has a tread portion 60, while Fig. 13B is also similar to Fig. 12B, with the sole including a velcro portion 61. The surface 63 to which The surface on which the Velcro bases are attached should preferably lie in the same plane and parallel to the theoretically ideal stability plane 51, since on soft ground this surface will bear the load more than the Velcro. The embodiment in Fig. 13C is similar to Fig. 12C, but shows an alternative tread construction 62. In any case, the load-bearing outer side of the tread or Velcro pattern 60-62 lies along the theoretically ideal stability plane 51.

Fig. 14 shows in a sectional view from behind the application of the invention to a shoe to produce an aesthetically pleasing and functionally effective design. Consequently, a practical design of the shoe incorporating the invention is feasible even when applied to shoes with heel risers 38 and a combined insole and outsole 39. Thus, the use of a sole surface and an outer contour of the sole which follow the theoretically ideal stability plane does not compromise the commercial appeal of shoes which incorporate the invention.

Fig. 15 shows a fully contoured sole design which follows the natural contour of the entire foot, both the lower surface and the sides. The fully contoured shoe sole is based on the assumption that the slightly rounded bottom when unloaded will deform and flatten under load in the same way that the bottom of the human foot is slightly rounded when unloaded but flattens under load; therefore the sole material must be of such a composition as to allow a natural deformation following that of the foot. The design is particularly applicable to the heel, but also to the rest of the shoe sole. By providing the closest fit to the natural shape of the foot, the fully contoured design allows the foot to function as naturally as possible. Under load, Fig. 15 would deform to look like Fig. 14. Viewed in this light, the naturally contoured side design in Fig. 14 is a more conventional, conservative design, which is a special case of the more general fully contoured design in Fig. 15, which is closest to the natural shape of the foot, but the least conventional. The amount of deformation allowance used in the design in Fig. 14, which obviously changes under different loads, is not an essential element of the applicant's invention.

Fig. 14 and 15 both show in frontal plane cross-section the essential concept underlying this invention, the theoretically ideal stability plane, which is also ideal for efficient natural movements of all kinds, including running, jogging or walking. Fig. 15 shows the most general case of the invention, the fully contoured design, which conforms to the natural shape of the unloaded foot. For any given person, the theoretically ideal stability plane 51 is determined first by the desired shoe sole thickness (s) in a frontal plane cross-section and second by the natural shape of the person's foot surface 29.

For the specific case shown in Fig. 14, the theoretically ideal stability plane for any specific person (or average size of persons) is determined firstly by the given shoe sole thickness (s) of the frontal plane cross-section; secondly by the natural shape of the person's foot; and thirdly by the width of the person's loaded footprint in the frontal plane cross-section, which is defined as the top of the shoe sole that is in contact with and supports the human foot sole, as shown in Fig. 4.

The theoretically ideal stability plane for the specific case is conceptually composed of two parts. In Figs. 14 and 4, the first part is shown as a line segment 31b of equal length and parallel to 30b at a constant distance (s) equal to the shoe sole thickness. This corresponds to a conventional shoe sole directly under the human foot and also corresponds to the flattened part of the bottom of the loaded foot sole 28b. The second part is the naturally contoured stability side outer edge 31a located at each of the first part, the line segment 31b. Each point of the contoured side outer edge 31a is located at a distance which is exactly the shoe sole thickness (s) from the nearest point on the contoured side inner edge 30a.

In summary, the theoretically ideal stability plane is the essence of the invention because it is used to create a geometrically accurate bottom contour of the To construct a shoe sole based on a top contour that corresponds to the contour of the foot. This invention specifically claims the precise geometric relationship just described. It can be unequivocally stated that any shoe sole contour, even if of similar contour, that exceeds the theoretically ideal stability plane will restrict the natural foot movement, while those that are less than that plane will degrade the natural stability in direct proportion to the amount of deviation.

Fig. 16 illustrates in a curve 70 the range of inward/outward rotational motion of the ankle center of mass 71 of the shoe according to the invention shown in a frontal plane cross-section at the ankle. Thus, in a static case where the center of mass 71 is approximately at the center of the sole, and assuming that the shoe rotates from 0º to 20º to 40º inward or outward, as shown in progressions 16A, 16B and 16C, the locus of motion points for the center of mass defines the curve 70, where the center of mass 71 maintains a motion of constant magnitude with no vertical component over 40º of inward or outward rotation. For the embodiment shown, the shoe sole stability equilibrium point is at 28º (at point 74) and in no case is there a pivoting edge to define a rotation point as in the case of Fig. 2. The inherent stability of the design from side to side provides for inversion (or outversion) control as well as lateral (or inversion) control. In marked contrast to conventional shoe sole designs, Applicant's shoe design creates virtually no abnormal torque to counteract natural inversion/outversion rotation or to destabilize the ankle joint.

Fig. 17 thus compares the range of motion of the center of mass for the invention as shown in curve 70 compared to curve 80 for the conventional wide heel pull-up and a curve 82 for a narrow rectangle the width of a human heel. Now, since the shoe stability limit at inward rotation is 28º, the shoe sole is stable at the inward rotation limit of about 20º for the bare foot. That factor and the wide bearing base, rather than the sharp bottom edge of the known prior art, make the contour design is stable even in the most extreme case as shown in developments 16A - 16C and allow the inherent stability of the bare foot to prevail without interference unlike existing non-interference designs by providing a constant, unchanging sole thickness in frontal plane cross sections. The stability superiority of the contour side design is thus evident when one observes how much flatter its center of mass curve 70 is than the existing popular wide upswept design 80. Curve 70 demonstrates that the contour side design has a significantly more efficient natural inward/outward rotation movement of 7º than the narrow rectangular design 82 the width of a human heel and is much more efficient than the conventional wide upswept design 80; at the same time, in extreme situations the contour side design is more stable than any conventional design due to the absence of a destabilizing moment.

Fig. 18A illustrates in pictorial form a comparison of a cross-section at the ankle of a conventional shoe with a cross-section of a shoe according to the invention when engaged with a heel. As can be seen in Fig. 18A, when the heel of the wearer's foot 27 engages an upper surface of the shoe sole 22, the shape of the heel of the foot and the shoe sole is such that the conventional shoe sole conforms to the contour of the bottom 43 and not to the contour of the sides of the foot 27. The result is that the conventional shoe sole 22 cannot follow the natural 7° inward/outward rotational movement of the foot and that the natural movement is counteracted by the shoe upper 21, particularly when reinforced by rigid heel reinforcements and motion control devices. This disruption of natural movement represents the fundamental misconception of currently available designs. This misconception on which existing shoe designs are based is that while the uppers of the shoe are considered part of the foot and conform to the shape of the foot, the sole of the shoe is functionally considered part of the floor and is therefore shaped like the floor and not like the foot.

In contrast, the new design as shown in Fig. 18B illustrates a proper conception of the shoe sole 28 as part of the foot and an extension of the foot with shoe sole sides contoured exactly like those of the foot and where the frontal plane thickness of the shoe sole between the foot and the ground is always the same and therefore completely neutral to the natural movement of the foot. With this basic proper conception as described in connection with this invention, the shoe can move naturally with the foot rather than constraining it, so that both natural stability and natural efficient movement coexist in the same shoe without any inherent conflict of design goals in the shoe.

Thus, the contoured shoe design of the invention brings together in a shoe design the cushioning and protection typical of modern shoes with the freedom from injury and functional efficiency, i.e. speed and/or stability, typical of barefoot stability and natural freedom of movement. Significant improvements in speed and durability are expected based on both improved effectiveness and the ability of a user to train harder without injury.

These figures also illustrate that the heel of the prior art shoe of Fig. 18A cannot pivot plus or minus 7º. In contrast, the heel of the shoe of the embodiment of Fig. 18B pivots with the natural movement of the heel of the foot.

Figures 19A-D illustrate in frontal plane cross sections the naturally contoured side design extended to the other natural contours under the weight-bearing foot such as the main longitudinal arch, the metatarsal (or forefoot) arch, and the instep between the heads of the metatarsal bones (forefoot) and the heads of the distal phalanxes (tips of the toes). As shown, the shoe sole thickness remains constant as the contour of the shoe sole follows the sides and bottom of the weight-bearing foot. Figure 19E shows a sagittal plane cross section of the sole conforming to the contour of the bottom of the weight-bearing foot with the thickness changing according to the heel rise 38.

Fig. 19F shows a horizontal plane top view of the left foot showing the regions 85 of the shoe sole that correspond to the flattened parts of the sole of the foot that are in contact with the ground under load. The contour lines 86 and 87 show approximately the relative height of the shoe sole contours above the flattened load-bearing regions 85, but within roughly the peripheral extent 35 of the upper surface 30 of sole 28. A horizontal plane bottom view (not shown) of Fig. 19F would be the exact inversion or mirror image of Fig. 19F (i.e., the contours of peaks and valleys would be exactly reversed).

Fig. 20A-D show in frontal plane cross sections the fully contoured shoe sole design extended to the bottom of the entire unloaded foot. Fig. 20E shows a sagittal plane cross section. The shoe sole contours under the foot 27 are the same as in Fig. 19A-E except that there are no flattened areas 85 corresponding to the flattened areas of the loaded foot 27. The purely rounded contour of the shoe sole follows that of the unloaded foot 27. A heel riser 38, the same as that of Fig. 19, is included in this embodiment but is not shown in Fig. 20.

Fig. 21 shows the horizontal plane view from above of the left foot according to the fully contoured design as described in Fig. 20A-E, but abbreviated along the sides to only essential structural support and propulsion elements. The density of the shoe sole material may be increased at the non-abbreviated essential elements to compensate for any increased compressive loading there. The essential structural support elements are the base and lateral tuberosity of the calcaneus 95, the heads of the first and fifth metatarsals 96, and the base of the fifth metatarsal 97. They must be supported both inferiorly and lateralwardly for stability. The main driving element is the head of the first distal phalanx 98. The medial (inner) and lateral (outer) sides supporting the base of the calcaneus are shown roughly along either side of the subtalar horizontal plane ankle axis in Fig. 21, but may be arranged more conventionally along the long axis of the shoe sole. Fig. 21 shows that the naturally contoured stability sides need not be used except in the essential areas identified. Weight savings and flexibility improvements can be made by eliminating the non-essential stability sides. Contour lines 85 through 89 show approximately the relative height of the shoe sole contours within roughly the peripheral extent 35 of the undeformed top surface 30 of shoe sole 28. A horizontal plane view (not shown) from below of Fig. 21 would be exactly opposite or inverted to Fig. 21 (ie, peaks and valleys of the contours would be exactly reversed).

Fig. 22A shows a development of street shoes with naturally contoured sole sides incorporating the features of the invention. Fig. 22A is the development of a theoretically ideal stability plane 51 as described above for a street shoe, where the thickness of the naturally contoured sides is equal to the sole thickness. The resulting street shoe with a properly contoured sole is thus shown in frontal plane heel cross-section in Fig. 22A with the side edges perpendicular to the ground, as is typical. Fig. 22B shows a similar street shoe with a fully contoured design including the bottom of the sole. Accordingly, the invention can be applied to an unconventional heel-elevated shoe, such as a simple wedge, or to the most conventional design of a typical hiking shoe, in which the heel is separated from the forefoot by a cavity under the instep. The invention can be applied to the heel of the shoe alone or to the entire sole of the shoe. When the invention is used in this way, the natural movement of any existing shoe design, except high heels or pointed heels, can be significantly enhanced by the naturally contoured shoe sole design.

Fig. 23 shows a method for measuring the shoe sole thickness to be used to construct the theoretically ideal stability plane of the naturally contoured side design. The constant shoe sole thickness of this design is measured at any point on the contoured sides along a line which, first, is perpendicular to a line tangent to that point on the surface of the naturally contoured side of the sole of the foot and which, second, passes through the surface point of the same sole of the foot.

Fig. 24 illustrates another approach to constructing the theoretically ideal stability plane, and one that is easier to use, the circle radius method. In this method, the pivot point (center of the circle) of a compass is placed at the beginning of the natural lateral contour of the sole of the foot (frontal plane cross-section), and a rough arc of 90º (or much less if accurately estimated) of a circle radius equal to (s) or the shoe sole thickness is drawn, describing the area farthest from the sole contour. This procedure is repeated over the entire natural lateral contour of the foot at very small intervals (the smaller the more accurate). When all the circle segments are drawn, the outer edge farthest from the sole contour (again frontal plane cross-section) is made at a distance of "s", and that outer edge coincides with the theoretically ideal stability plane. Both this method and the one described in Fig. 23 would be used for both manual and CADCAM applications.

The shoe sole according to the invention can be manufactured by approximating the contours as indicated in Figs. 25A, 25 and 26. Fig. 25A shows a frontal plane cross-section of a construction wherein the sole material in the areas 107 is so relatively soft that it easily deforms to the contour of shoe sole 28 of the proposed invention. In the proposed approximation as seen in Fig. 25B, the heel cross-section has a sole top 101 and a lower sole edge surface 102 which, when deformed, follows an inserted theoretically ideal stability plane 51. The sole edge surface 102 terminates in a laterally extending part 103 which is connected to the heel of the sole 28. The laterally expanding part 103 is made of a flexible material and structured to cause its bottom 102 to end up during deformation so that it is parallel to the employed theoretically ideal stability plane 51. Sole material in specific areas 107 is extremely soft to allow sufficient deformation. Consequently, in a dynamic case, the outer edge contour assumes approximately the theoretically ideal stability shape described above as a result of the deformation of the part 103. The top 101 deforms in a similar manner so that it is approximately runs parallel to the natural contour of the foot, as described by the lines 30a and 30b shown in Fig. 4.

It is presently envisaged that the controlled or programmed deformation can be provided by one of two techniques. One involves cutting or scalloping the shoe sole sides, particularly the insole, so that the outsole bends inward to the correct contour under pressure. The second uses a readily deformable material 107 in a conical shape on the sides to deform to the correct contour under pressure. While such techniques produce stability and natural movement, which is a significant improvement over conventional designs, they are inherently inferior to contours produced by simple geometric shaping. First, the actual deformation must be produced by pressure, which is unnatural and does not occur in a bare foot, and second, only approximations by deformation are possible, even with sophisticated design and manufacturing techniques, taking into account the particular gait or body weight of the person. Consequently, the deformation is limited to a less significant effort to correct the contours from surfaces that approximate the ideal curve to a first approximation.

The theoretically ideal stability plane can also be approximated by a plurality of line segments 110, such as tangents, chords, or other lines, as shown in Figure 26. Both the top of the shoe sole 28, which coincides with the side of the foot 30A, and the bottom 31a of the naturally contoured side can be approximated. While a single approximation of the flat plane 110 can correct many of the biomechanical problems encountered in existing designs because it can provide a rough approximation of both the natural contour of the foot and the theoretically ideal stability plane 51, the single plane approximation is not currently preferred because it is the least optimal. By increasing the size of the flat plane surfaces formed, the curve more closely approximates the ideal precise design contours, as described above. Single and dual plane approximations are shown as line segments in the cross section illustrated in Fig. 26.

Fig. 27 shows a frontal plane cross-section of an alternative embodiment for the invention showing a stability side component 28a which is mathematically determined to be approximately consistent with the sides of the foot. (The central or load bearing portion of the shoe sole 28b would be as described in Fig. 4.) The side portions 28a would be a quadrant of a circle of radius (r + r¹), where the distance r must be equal to the sole thickness (s); consequently, the sub-quadrant of radius (r¹) is removed from the quadrant (r + r¹). In geometric terms, therefore, the component side 28a is a quarter or other portion of a ring. The center of rotation 115 of the quadrants is chosen to achieve an upper sole side surface 30a which very closely approximates the natural contour of the side of the human foot.

Fig. 27 provides a direct link to another invention by the applicant, a shoe sole design with quadrant stability sides.

Fig. 28 shows a shoe sole design which allows unimpeded inward/outward rotational movement of the calcaneus by providing maximum flexibility of the shoe sole, particularly between the base of the calcaneus 125 (heel) and the metatarsal heads 126 (forefoot) along an axis 120. Unnatural torsion occurs about that axis when flexibility is insufficient, so that a conventional shoe sole interferes with inward/outward rotational movement by restricting it. The object of the design is to allow the relatively more mobile calcaneus (in inward and outward rotation) to articulate freely and independently of the relatively more fixed forefoot than the fixed or fused structure of the two in conventional designs. In a sense, freely moving joints are created in the shoe sole which run parallel to those of the foot. The design is intended to eliminate virtually all sole material between the heel and the forefoot, except under one of the essential structural support elements described above, the base of the fifth metatarsal 97. Optimal support for the main longitudinal arch 121 can also be maintained for runners with significant foot inversion, although this would not be necessary for many runners. The forefoot can be divided (not shown) into its essential Support and propulsion elements, the individual metatarsal heads and the heads of the distal phalanxes are subdivided so that a freely articulated shoe sole support and propulsion element is connected in parallel to each main articulation set of the foot, an anthropomorphic design; various aggregations of the subdivisions are also possible. An additional advantage of the design is that it provides for better flexibility along axis 122 for the forefoot during the toe-off phase of the running stride even in the absence of any other embodiments of Applicant's invention; that is, the benefit also applies to conventional shoe sole designs.

Fig. 28A shows, in a sagittal plane cross-section, a special design that maximizes flexibility, with large non-essential sections removed for flexibility and connected only by a top layer (horizontal plane) of non-stretching fabric 123, such as Dacron polyester or Kevlar. Fig. 28B shows another special design with a thin top sole layer 124 instead of fabric and a different structure for the flexibility sections: a design variation that provides greater structural support but less flexibility, although still more than conventional designs. Not shown is a simple, minimalist approach consisting of individual frontal plane slits in the shoe sole material (all layers or part thereof): the first midway between the base of the calcaneus and the base of the fifth metatarsal, and the second midway between that base and the metatarsal heads. Fig. 28C shows a bottom view (horizontal plane) of the inward/outward rotation flexibility structure.

Fig. 29 shows a frontal plane cross-section of an important element of Applicant's shoe design for stabilizing the quadrants 26 on the outer edge of a shoe sole 28b, shown generally by the reference numeral 28. It is therefore a key feature of Applicant's invention that the unnaturally sharp edge, particularly in high-top shoes, is avoided and instead a rounded shoe sole edge 25 is preferred as shown in Fig. 29. The side or edge 25 of the shoe sole 28 is contoured similarly to the natural shape of the side or edge of the human foot, but in a geometrically precise manner to follow a theoretically ideal stability plane. According to the invention, the thickness (s) of the shoe sole 28 is kept exactly constant even when the shoe sole is tilted to one side or forward or backward. Accordingly, the side stabilizing quadrants 26 according to Applicant's invention are defined by a radius 25a corresponding to the thickness 34 of the shoe sole 28b so that the shoe sole in cross section has a stable shoe sole 28 having a surface 25 at the outer edge quadrants 26 which represents part of a theoretically ideal stability plane and is described by a radius 25a corresponding to the sole thickness (s) and a quadrant center of rotation at the outer edge 41 on the top of the shoe sole 30b which coincides with the load-bearing footprint of the wearer. The outer edge 32 of the quadrant 26 coincides with the horizontal plane of the top of the shoe sole 28b, while the other edge of the quadrant 26 is perpendicular to the edge 32 and coincides with the vertical sides 34 of the shoe sole 28b. In practice, the shoe sole is preferably formed integrally from the sections 28b and 26. The outer edge 32 can also extend at an angle to the sole surface. The theoretically ideal stability plane includes the contours 25 which merge into the bottom 31b of the sole 28b.

Preferably, the peripheral area of the shoe sole 36 includes all of the support structures of the foot, but extends no further than the outer edge of the flat part of the sole of the foot 37 as defined by a loaded footprint as shown in Fig. 4D, which is a plan view of the shoe sole surface 30b. Fig. 4D thus shows a foot contour with the reference numeral 37 and a corresponding recommended sole contour 36. A horizontal plane contour of the shoe sole top surface should thus preferably match as closely as possible the loaded portion of the sole of the foot with which it comes into contact. As best seen in Fig. 4D, such a horizontal contour should remain consistent throughout the thickness of the shoe sole so as to eliminate negative or positive pull-up of the sole so that the sides are exactly perpendicular to the horizontal plane as shown in Fig. 29B. Preferably, the density of the shoe sole material is uniform.

Another important feature of Applicant's invention is shown schematically in Fig. 30. While the heel riser or wedge increases the thickness (s) of the shoe sole in the longitudinal direction of the shoe, the side quadrants 26 preferably increase by exactly the same amount according to the guidelines discussed in connection with Fig. 29. According to Applicant's embodiment, the radius 25a of curvature (r) of the side quadrant is always equal to the constant thickness (s) of the shoe sole in the frontal cross-sectional plane.

As shown in Fig. 30B, in a shoe that follows a more conventional horizontal plane contour, the sole can be significantly improved according to Applicant's invention by adding an outside quadrant 26 with a radius that varies accordingly with the thickness of the shoe sole and changes in the frontal plane according to the shoe heel rise. As shown in Fig. 30B, the radius of curvature of quadrant 26a is thus equal to the thickness s1 of the shoe sole 28b, which is thicker than the shoe sole (s) shown in Fig. 30A by an amount equivalent to the heel rise (s - s1). In the generalized case, the radius (r1) of the quadrant is therefore always equal to the thickness (s) of the shoe sole.

Fig. 31, in contrast to Fig. 10B, shows how the center of rotation of the quadrant sole side 41 is maintained at a constant distance (s) from the ground through various degrees of rotation of the shoe sole edge 25. By maintaining a constant distance from the ground, the stable shoe allows the foot to respond to the ground as if it were barefoot, while providing protection and cushioning. In a preferred embodiment, the new contoured design assumes that the shoe uppers 21, including the heel leathers and other motion control devices, effectively position and hold the foot on the loaded footprint area of the shoe sole.

Fig. 32 shows an embodiment of the invention which uses only a part of the theoretically ideal stability plane 51 in the quadrants 26 to reduce the weight and volume of the sole, while accepting a certain loss of stability of the shoe. Fig. 32A shows the preferred embodiment described above in connection with Fig. 30, wherein the outer quadrant 50 follows a theoretically ideal stability plane 51 around a center 52 and has a surface 53 which is coplanar (or at an angle) to the surface of the shoe sole 54. As in Fig. 29, the contoured surfaces 50 and the bottom of the sole 54A lie along the theoretically ideal stability plane. As shown in Fig. 32B, an engineering compromise results in a shortcut within the ideal stability plane 51 by forming a quadrant surface 53a at an angle to the upper plane of the shoe sole 54 such that only a portion of the quadrant defined by the radius along the surface 50a is coplanar with the theoretically ideal stability plane 51. Fig. 32C shows a similar embodiment wherein the engineering compromise results in a region 50b which lies along the theoretically ideal stability plane 51. The region 50b merges into a second region 56 which in turn merges into the surface 53a of the quadrant.

The embodiment of Fig. 32 may be advantageous for areas of the shoe sole that are used less frequently, so that the additional side portion is used less frequently. For example, a shoe can typically roll out laterally in an inward turn up to about 20º, on the order of 100 times for each time it rolls out to 40º. The additional shoe weight to cover this entire area is still approximately equivalent to covering the limited area. Since in a racing shoe this weight may not be desirable, a compromise solution of the type shown in Fig. 32C is possible.

Fig. 33 shows in Figs. 33A - 33C a further development of a street shoe with a contoured sole incorporating the features of the present invention. Fig. 33A shows the cross-section of a heel of a typical street shoe 94 with a sole region 79 and a heel riser 81. Fig. 33B shows a theoretically ideal stability plane 51 as described above for such a street shoe, wherein the radius (r) of curvature of the sole edge and the shoe sole thickness are equal. The corresponding street shoe with a correctly contoured sole is thus shown in Fig. 33C, with a reduced side edge thickness for a less bulky and more aesthetically pleasing appearance. Accordingly, the present invention can be used for an unconventional shoe with a heel riser, e.g. a simple wedge, or for a completely conventional design of a typical hiking shoe in which the heel is separated from the forefoot. separated by a cavity under the instep. For the embodiment of Fig. 33, the theoretically ideal stability plane is determined by the shoe sole width and thickness based on an optimum width of the human heel measured along the width of the hard human heel tissue on which the heel is to rotate in an inward/outward rotation. With the invention thus applied, the stability and natural movement of any shoe design, except high heels or stilettos, can be greatly improved by contouring the outsole to the theoretically ideal stability plane.

34A and 34B show that it may be desirable to use wedge inserts 84 in the sole of the invention to support the heel bones. As can be seen from Fig. 34A, when a prior art shoe is rotated inwardly through an angle of 20 degrees, the heel bone 99 is not supported. This is about the greatest natural inward rotation of the heel at which the heel bone, located laterally on the heel bone, comes into contact with the ground and restricts further sideways movement. When a conventional wide shoe sole reaches such a limit of inward rotation, the heel bone 99 in the region 100 is not supported at all by the sole; however, when the foot is bare, the heel bone is in contact with the ground and provides secure support. To this end, a wedge 84 of relatively firm material, usually approximately equivalent to the density of the insole and heel rise, is placed on the shoe sole beneath the insole to provide lateral support to the heel bone. Such a wedge support may also be used in the inventive sole shown in Fig. 34B. Typically, such a wedge tapers toward the toe of the shoe and is contoured to conform to the heel bone and its bone. If preferred, the wedge may be integrated into and be a part of a typical heel of an insole.

The shoe sole according to the invention can be manufactured by approximating the contours as shown in Fig. 35 and 36. In the approximation proposed in Fig. 35, the heel cross-section includes a sole top 101 and a sole edge top 104 which follow the theoretically ideal stability plane 51. The sole edge surface 104 ends in a laterally extending section 105 connected to the heel 106. The laterally extending section 105 consists made of a flexible material and is designed so that its underside 105a ends at the theoretically ideal stability plane during deformation. In a dynamic case, the outer edge contour therefore assumes approximately the shape described above as a result of the deformation of section 105.

Currently, it is believed that controlled or programmed deformation can be achieved by two methods. In one, the sides of the shoe sole, particularly at the insole, can be tapered or grooved so that the outsole bends inwards to the correct contour under pressure. The second method uses a slightly deformable material in a tapered shape on the sides that deforms to the correct contour under pressure. While such methods can achieve stability and natural movement, which is a significant improvement over conventional designs, they are inherently inferior to contours created by simple geometric shaping. Firstly, the actual deformation must be created by means of pressure, which is unnatural and does not occur with a bare foot. Secondly, even with sophisticated design and manufacturing processes, only approximations through deformation are possible when taking into account the specific walking style or body weight of a person. The deformation is therefore limited to a minor attempt to correct the contours of surfaces that primarily approximate the ideal curve.

The theoretically ideal stability curve 51 can also be approximated by a plurality of line segments 110, such as tangents and tendons, as shown in Figure 36. While a single flat plane approximation can correct many of the biomechanical problems encountered in current designs by almost completely removing the region outside the theoretically ideal stability plane 51, a single plane approximation is not currently preferred because it is the least optimal. By increasing the number of flat planar surfaces, the curve more closely approximates the ideal design contour, as described above.

Fig. 37 shows in a frontal plane cross-section the basic idea underlying the invention, the theoretically ideal stability plane, which also ensures efficient natural movements of all kinds, including running, jogging and walking, are theoretically ideal. For each individual person (or the average size of individuals), the theoretically ideal stability plane is determined first by using the given shoe sole thickness (s) and then by using the width of the foot of the person's loaded footprint 30b in the frontal plane cross-section; the loaded footprint 30b is defined as the top of the shoe sole that is in physical contact with and supports the human foot sole.

The theoretically ideal stability plane consists conceptually of two parts. The first part is a line segment 31b of equal length and parallel to 30b at a constant distance (s) equal to the shoe sole thickness. This corresponds to a conventional shoe sole directly under a person's foot. The second part is a quadrant edge 25 or a quarter of a circle (which can be extended to a semicircle) on both sides of the first part, i.e. line segment 31b. The quadrant edge 25 lies at the radius (r) corresponding to the shoe sole thickness (s) from a center of rotation 41, which forms the outermost point on both sides of the line segment 30b. In summary, it can be said that the theoretically ideal stability plane forms the most important point of the invention, since it serves to determine a geometrically precise lower contour of the shoe sole. Furthermore, the present invention expressly claims the precisely defined geometric relationship just described. Clearly, any shoe sole contour, even those of similar quadrant contour, that exceeds the theoretically ideal stability plane will restrict natural foot movement, while any smaller contour will impair natural stability.

It is thus possible to make an adaptation to a definition related to the previous idea empirically rather than theoretically at some point in the future. It is conceivable that, unlike the rest of the foot, a definition of line segment 30b at the base of the human heel could be the width of the very hard tissue (bone, cartilage, etc.) rather than the loaded footprint, since the heel width may be the geometrically effective turning width that the shoe heel must exactly match in order to turn optimally with the human heel. For the typical size 10D man, this width of the very hard tissue is 1.75 inches versus 2.25 inches for the loaded footprint of the heel. Smaller values for the heel width 30b, even much smaller ones, can, although not optimal, be used in street shoes other than sports shoes to achieve most of the increase in stability and efficiency achieved by the invention, while maintaining the appearance of conventional shoes, especially that of shoes with higher heels.

However, this is a matter of experience, not theory. Until more experience has been gained, the optimal heel width must be estimated. However, the optimal width of the human heel pivot is a scientific question that must be determined empirically, if possible, and does not represent a change to the basic concept of the theoretically ideal stability plane claimed by the invention. Furthermore, the more precise the definition, the more important an accurate fit becomes and relatively minor misalignments could lead to problems with pronation control, for example, negating any possible benefits.

Fig. 38 shows a non-optimal but interim or low cost approach to shoe sole construction, where the insole and heel riser 127 are manufactured conventionally or nearly conventionally (leaving at least the bottom of the insole flat while the sides may be contoured), while the bottom of the outsole 128 has most or all of the special contours of the new design. Not only would this completely or largely limit the special contours to the outsole, which would be specially molded, it would also facilitate assembly since two flat surfaces of the bottom of the midsole and the top of the outsole could be mated with less difficulty than two contoured surfaces, as would otherwise be the case. The advantage of this approach can be seen in the naturally contoured design example illustrated in Fig. 38A, which shows some contouring on the relatively softer midsole sides, which are subject to less wear but would benefit from a greater tensile force for stability and ease of deformation, while the relatively harder contoured outsole provides good wear characteristics for the stressed areas.

Fig. 38B shows in a quadrant side design the concept applied to conventional street shoe heels which are usually separated from the forefoot by a hollow step-in area under the main longitudinal arch. Fig. 38C shows in a foreplane cross section the concept applied to the quadrant side or single plane design and in Fig. 38D indicates in the dashed area 129 of the outsole the area that should have a honeycomb pattern (with the axis on the horizontal plane) to reduce the density of the relatively hard outsole to that of the midsole material so as to provide a relatively uniform shoe density. Fig. 38E shows in a bottom view the outline of an outsole 128 made of flat material that can be topologically matched to a contoured insole in either a single or two-plane configuration by limiting the lateral surfaces to be matched to the essential areas discussed in Fig. 21; by this method the surfaces of the contoured insole and the flat outsole can be made to satisfactorily merge into one another by a close coincidence, which would be topologically impossible if all of the lateral surfaces were retained in the outsole.

39A-39C, frontal plane cross sections, show an improvement over the previously described embodiments of the invention of the naturally contoured shoe sole side. As previously stated, a primary purpose of that design is to allow the shoe sole to easily pivot with the foot 90 from side to side, thereby following the natural inward and outward pivoting motion of the foot; in conventional designs shown in Fig. 39A, such foot motion is forced to occur in the upper of the shoe 21, which counteracts the motion. The improvement is to accurately position and stabilize the foot, particularly the heel, relative to the preferred embodiment of the shoe sole; doing so facilitates the responsiveness of the shoe sole in following the natural motion of the foot. Correct positioning is essential to the invention, especially when the very narrow or "hard tissue" definition of heel width is used. An incorrect or shifted relative position will reduce the inherent efficiency and stability by reducing the effective thickness of the Quadrant side 26 to a thickness less than that of the shoe sole 28b. As shown in Figs. 39B and 39C, naturally contoured inner stability sides 131 maintain the pivoting edge 31 of the loaded sole of the foot in the proper position for contact with the flat top of the conventional shoe sole 22 so that the sole thickness (s) is maintained at a constant thickness (s) in the naturally contoured sides 28a as the shoe is rotated inwardly or outwardly following the theoretically ideal stability plane 51.

The form of the improvement is in the form of inner sole stability panels 131 that follow the natural contour of the sides 91 of the heel of the foot 27 and thereby cover the heel of the foot. The inner stability panels 131 can be placed directly on the top of the sole and heel structure or directly under the shoe insole (which is inseparably connected thereto) or anywhere in between. The inner stability panels are similar in construction to heel caps incorporated into insoles as are currently in common use, but differ because of their material density, which can be relatively firm like the insole, not soft like the insole. The difference is that because of their higher relative density, preferably like that of the top insole, the inner stability panels function as part of the shoe sole, providing structural support for the foot and not just the gentle cushioning and abrasion protection of a shoe insole. In the most general sense, insoles should be considered structurally and functionally part of the shoe sole, just like any shoe material between the foot and the ground, such as the bottom of the upper leather in a plain-finished shoe or the edge in a welted shoe.

The improvement in internal lateral stability is particularly useful in converting existing shoe sole design embodiments 22, as made within the known art, into an effective embodiment of the lateral stability quadrant 26 of the invention. This feature is of importance in the manufacture of prototypes and initial production of the invention and also in beginning processes of low cost production, since such production would be very close to the known art.

The improvement of the inner side stability is most essential in covering the sides and back of the heel of the foot and is therefore essential at the top of the heel 27 of the shoe sole 28, but can also be extended around the rest of the shoe sole top in whole or in part. The size of the inner stability sides should, however, be tapered downward in proportion to any reduction in the thickness of the shoe sole in the sagittal plane.

Fig. 40A-40C, frontal plane cross sections, show the same internal shoe stability side enhancement as occurs in the previously described embodiments of the naturally contoured side design. The enhancement positions and stabilizes the foot relative to the shoe sole 28 and maintains the constant shoe sole thickness (s) of the naturally contoured side design 28a as shown in Fig. 40B and 40C; Fig. 40A shows a conventional design. The internal shoe stability sides 131 conform to the natural contour of the foot sides 29, which determine the theoretically ideal stability plane 51 for the shoe sole thickness (s). The other features of the improvement as in the embodiment 28 with the naturally contoured shoe sole sides are the same as described above with reference to Figures 39A to 39C for the embodiment with the lateral stability quadrants. From a comparison of Figures 40C and 39C it will be apparent that the two different approaches, i.e. that with the quadrant sides and that with the naturally contoured sides, can produce some similarly designed shoe sole embodiments through the use of internal shoe stability sides 31. In essence, both approaches provide an inexpensive or intermediate method for adapting existing conventional "flat plate" shoe manufacture to the naturally contoured design described in the preceding figures.

Consequently, it will be clearly understood by those skilled in the art that the foregoing description has been made in the manner of preferred embodiments and that many changes and modifications may be made without departing from the scope of the present invention, which is to be defined by the appended claims.

Claims (45)

1. Shoe sole (28) for a shoe with: a lateral sole side, a medial sole side and a middle sole section located between the lateral and medial sole sides; a midsole (127) having an inner surface (30) of the midsole (127) and a midsole outer surface, the midsole (127) having portions disposed in at least the central sole portion and a first side of the shoe sole (28); wherein the lateral sole side has a lateralmost portion that is located outside a vertical line running along the lateralmost extent of the inner surface (30) of the midsole (127); wherein the medial sole side has a medial lateralmost portion located outside a vertical line running along the lateralmost extent of the inner surface (30) of the midsole (127); an outsole (128); wherein the midsole outer surface of the portion of the midsole (127) disposed on the first side of the shoe sole (28) extends upwardly along the first side of the shoe sole (28) to a vertical height above the vertical height of the lowest point of the inner surface (30) of the midsole (127), viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state; and wherein the portion of the midsole (127) disposed on the first side of the shoe sole (28) comprises a midsole inner and outer surfaces that is greater than the thickness between the midsole inner and outer surfaces of the portion of the midsole (127) disposed in the central sole portion, viewed in a foreplane cross-section when the shoe sole (28) is in an upright, unloaded condition; characterized in that: the midsole outer surface of the portion of the midsole (127) disposed on the first side of the shoe sole (28) has a lowermost part that is concavely rounded with respect to an intended location of the wearer's foot within the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 2. Shoe sole (28) according to claim 1, wherein the outer surface (31) of a first lateralmost portion of the shoe sole (28) has at least one portion that is concavely rounded with respect to the intended position of the wearer's foot in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state; and wherein the portion of the midsole (127) having a concavely rounded midsole outer surface extends into the portion of the first lateralmost portion of the shoe sole (28) having the concavely rounded outer surface (31), viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 3. Shoe sole (28) according to one of claims 1 to 2, wherein the midsole outer surface of the midsole (127) extends above the vertical height of the lowest point of a side portion of the inner surface (30) of the midsole (127) disposed on the same side of the shoe sole (28), viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 4. Shoe sole (28) according to one of claims 1 to 3, wherein the inner surface (30) of the portion of the midsole (127) which is on the first side of the shoe sole (28) is arranged, further comprising a portion which is concavely rounded with respect to an intended position of the wearer's foot in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 5. The shoe sole (28) of claim 4, wherein the concavely rounded portion of the inner surface (30) of the midsole (127) extends substantially to a lateral-most extent of the inner surface (30) of the midsole (127), viewed in a front-plane cross-section when the shoe sole (28) is in an upright, unloaded state. 6. Shoe sole (28) according to one of claims 4 to 5, wherein the concavely rounded portion of the inner surface (30) of the midsole (127) is substantially coextensive with at least one concavely rounded portion of the midsole outer surface of the same portion of the midsole (127), viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 7. The shoe sole (28) of any one of claims 1 to 6, wherein the concavely rounded portion of the midsole outer surface extends to the most lateral extent of the midsole outer surface, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded condition. 8. Shoe sole (28) according to one of claims 1 to 7, wherein the concavely rounded portion of the midsole outer surface extends uniformly through the lateral-most extent of the midsole outer surface, viewed in a front-plane cross-section when the shoe sole (28) is in an upright, unloaded state. 9. Shoe sole (28) according to one of claims 1 to 8, wherein the concavely rounded portion of the midsole outer surface extends uniformly through the lowermost part of the midsole outer surface, in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 10. Shoe sole (28) according to one of claims 1 to 9, wherein at least a portion of the midsole (127) extends to a second side of the shoe sole (28), viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state; the lowermost part of the midsole outer surface of the portion of the midsole (127) disposed on the second side of the shoe sole (28) is concavely rounded with respect to an intended position of the wearer's foot in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state; and the portion of the midsole (127) disposed on the second side of the shoe sole (28) and having a concavely rounded midsole outer surface further has a thickness (s) that is greater than the thickness of the portion of the midsole (127) disposed in the central sole portion, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 11. The shoe sole (28) of claim 10, wherein the concavely rounded portion of the midsole outer surface of the portion of the midsole (127) disposed on the second side of the shoe sole (28) extends to the lateral-most extent of the midsole outer surface, viewed in a front-plane cross-section when the shoe sole (28) is in an upright, unloaded condition. 12. The shoe sole (28) of claim 10, wherein the concavely rounded portion of the midsole outer surface of the portion of the midsole (127) disposed on the second side of the shoe sole (28) extends uniformly through the lateral-most extent of the midsole outer surface, viewed in a front-plane cross-section when the shoe sole (28) is in an upright, unloaded state. 13. Shoe sole (28) according to one of claims 10 to 12, wherein the first and second sides of the shoe sole (28) are viewed in the same front plane cross-section. 14. Shoe sole (28) according to one of claims 1 to 13, wherein the midsole outer surface of the at least one portion of the midsole (127) disposed on one side of the shoe sole (28) is concavely rounded with respect to the intended position of the wearer's foot in the shoe, at one or more positions that substantially correspond to the positions of the following structural support and locomotion elements of the foot of an intended wearer once in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal (96d, 96g), the base of the fifth metatarsal (95a, 95c), the head of the fifth metatarsal (96e, 96c), and the main longitudinal arch of the foot, viewed in a front plane cross-section at one or more positions when the shoe sole (28) is in an upright, unloaded state. 15. The shoe sole (28) of claim 14, wherein the midsole outer surface of the at least one portion of the midsole (127) disposed on a side of the shoe sole (28) is concavely rounded relative to an intended wearer's foot location in the shoe, at least at positions substantially corresponding to the positions of the following structural support and locomotion elements of the foot of an intended wearer when in the shoe: the base of the calcaneus (95b, 95d), and the lateral tuberosity of the calcaneus (95c, 95a), viewed in a frontal plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 16. Shoe sole (28) according to claim 14, wherein the midsole outer surface of the at least one portion of the midsole (127) arranged on one side of the shoe sole (28) is concavely rounded with respect to an intended wearer foot position in the shoe, at least at positions which substantially correspond to the positions of the following structural support and propulsion elements of the intended wearer's foot when in the shoe: the head of the fifth metatarsal bone (96e, 96c) and the head of the first metatarsal bone (96d, 96g), viewed in a foreplane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 17. The shoe sole (28) of claim 14, wherein the midsole outer surface of the at least one portion of the midsole (127) disposed on a side of the shoe sole (28) is concavely rounded relative to an intended wearer's foot location in the shoe, at least at positions substantially corresponding to the positions of the following structural support and locomotion elements of the foot of an intended wearer when in the shoe: the head of the fifth metatarsal (96e, 96c), the head of the first metatarsal (96d, 96g), the base of the calcaneus (95b, 95d) and the lateral tuberosity of the calcaneus (95c, 95a), viewed in a front plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 18. Shoe sole (28) according to claim 14, wherein the midsole outer surface of the at least one portion of the midsole (127) disposed on a side of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot position in the shoe, at least at positions that substantially correspond to the positions of two of the following structural support and locomotion elements of the foot of an intended wearer when in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal bone (96d, 96g), the base of the fifth metatarsal bone (95a, 95c), the head of the fifth metatarsal bone (96e, 96c), and the Main longitudinal arch of the foot, viewed in a frontal plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 19. Shoe sole (28) according to claim 14, wherein the midsole outer surface of the at least one portion of the midsole (127) which is on one side the shoe sole (28) is concavely rounded with respect to an intended wearer's foot position in the shoe, at least at positions which substantially correspond to the positions of three of the following structural support and locomotion elements of the foot of an intended wearer when the latter is in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal bone (96d, 96g), the base of the fifth metatarsal bone (95a, 95c), the head of the fifth metatarsal bone (96e, 96c), and the main longitudinal arch of the foot, viewed in a frontal plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 20. Shoe sole according to claim 14, wherein the midsole outer surface of at least a portion of the midsole (127) disposed on one side of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot location in the shoe, at least at positions that substantially correspond to the positions of four of the following structural support and locomotion elements of the foot of an intended wearer when in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal bone (96d, 96g), the base of the fifth metatarsal bone (95a, 95c), the head of the fifth metatarsal bone (96e, 96c), and the main longitudinal arch of the foot, viewed in a frontal plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 21. A shoe sole according to claim 14, wherein the midsole outer surface of at least a portion of the midsole (127) disposed on one side of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot position in the shoe, at least at positions substantially corresponding to the positions of five of the following structural support and locomotion elements of the foot of an intended wearer when located in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal bone (96d, 96g), the base of the fifth metatarsal bone (95a, 95c), the head of the fifth metatarsal bone (96e, 96c), and the main longitudinal arch of the foot, viewed in a foreground plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 22. Shoe sole according to claim 14, wherein the midsole outer surface of at least a portion of the midsole (127) disposed on one side of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot position in the shoe, at least at positions that substantially correspond to the positions of six of the following structural support and locomotion elements of the foot of an intended wearer when in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal bone (96d, 96g), the base of the fifth metatarsal bone (95a, 95c), the head of the fifth metatarsal bone (96e, 96c), and the Main longitudinal arch of the foot, viewed in a frontal plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 23. Shoe sole according to claim 14, wherein the midsole outer surface of at least a portion of the midsole (127) disposed on one side of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot location in the shoe, at least at positions that substantially correspond to the positions of the following structural support and locomotion elements of the foot of an intended wearer when in the shoe: the base of the calcaneus (95b, 95d), the lateral tuberosity of the calcaneus (95c, 95a), the head of the first distal phalanx (98, 98a), the head of the first metatarsal bone (96d, 96g), the base of the fifth metatarsal bone (95a, 95c), the head of the fifth metatarsal bone (96e, 96c), and the main longitudinal arch of the foot, viewed in a frontal plane cross-section at these positions when the shoe sole (28) is in an upright, unloaded state. 24. Shoe sole (28) according to one of claims 1 to 23, wherein the outsole (128) extends to a lateralmost portion of the shoe sole (28); and at least a portion of the outer surface (31) of the outsole (128) disposed in the lateralmost portion of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot location in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 25. Shoe sole (28) according to one of claims 1 to 24, wherein the thickness is defined as the shortest distance between a point on the inner surface (30) of the midsole (127) and the nearest point on the midsole outer surface, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 26. Shoe sole (28) according to one of claims 1 to 24, wherein the thickness is defined as a radial thickness; and the radial thickness represents the length of a line extending perpendicular to a line tangent to the inner surface (30) of the midsole (127) from the inner surface (30) of the midsole (127) to the midsole outer surface at the measured position, viewed in a foreplane cross-section when the shoe sole (28) is in an upright, unloaded state. 27. Shoe sole (28) according to one of claims 1 to 26, wherein the midsole outer surface of the at least a portion of the midsole (127) disposed in the central sole portion is substantially planar, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 28. Shoe sole (28) according to one of claims 1 to 26, wherein the midsole outer surface of at least a portion of the midsole (127) arranged in the central sole portion is concavely rounded with respect to an intended wearer's foot position in the shoe, viewed in a front plane cross-section, when the shoe sole (28) is in an upright, unloaded state. 29. Shoe sole (28) according to one of claims 1 to 28, wherein the midsole inner surface of at least a portion of the midsole (127) disposed in the central sole portion is substantially flat, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded condition. 30. Shoe sole (28) according to one of claims 1 to 28, wherein the midsole inner surface of at least a portion of the midsole (127) arranged in the central sole portion is concavely rounded with respect to an intended wearer foot position in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 31. The shoe sole (28) of any one of claims 1 to 30, wherein the at least one portion of the midsole (127) disposed on a side of the shoe sole (28) comprises a midsole portion having a greatest thickness, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state, and at least one tapered portion at a position adjacent to and anterior or posterior to the midsole portion having a greatest thickness, the tapered portion having a thickness that decreases from the portion having a greatest thickness to a lesser thickness, viewed in a horizontal plane when the shoe sole (28) is in an upright, unloaded state. 32. Shoe sole (28) according to claim 31, wherein the thickness of the at least one tapered portion of the midsole (127) gradually decreases from the midsole portion of greatest thickness to a lesser thickness, viewed in a horizontal plane when the shoe sole (28) is in an upright, unloaded state. 33. Shoe sole (28) according to one of claims 31 to 32, wherein the at least one tapered portion of the midsole (127) is concavely rounded with respect to the intended wearer's foot position in the shoe, viewed in a horizontal plane when the shoe sole (28) is in an upright, unloaded state. 34. Shoe sole according to one of claims 31 to 33, wherein the at least one tapered portion of the midsole (127) is arranged in front of the midsole portion with the greatest thickness, viewed in a horizontal plane. 35. Shoe sole (28) according to one of claims 31 to 33, wherein the at least one tapered portion of the midsole (127) is arranged behind the midsole portion of greatest thickness, viewed in a horizontal plane. 36. Shoe sole (28) according to one of claims 31 to 33 with at least two tapered sections of the midsole (127), wherein a tapered section of the midsole (127) is arranged behind the midsole section with the greatest thickness and a second tapered section of the midsole (127) is arranged in front of the midsole section with the greatest thickness, viewed in a horizontal plane. 37. Shoe sole (28) according to one of claims 1 to 36, wherein the thickness of the shoe sole (28) changes, viewed in a sagittal plane, when the shoe sole (28) is in an upright, unloaded state. 38. Shoe sole (28) according to claim 37, wherein the thickness of the shoe sole (28) decreases gradually, viewed in a sagittal plane when the shoe sole (28) is in an upright, unloaded state. 39. Shoe sole (28) according to one of claims 1 to 38, wherein the shoe sole (28) further comprises a heel elevation (127 or 38), a full sole taper (38b) and/or a toe taper (38a). 40. Shoe sole (28) according to one of claims 1 to 39, wherein the shoe is a sports shoe. 41. A shoe sole (28) according to any one of claims 1 to 40, wherein the concavely rounded portion of the midsole outer surface is concavely rounded with respect to a nearest portion of a side of an intended wearer foot layer in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded condition. 42. A shoe sole (28) according to any one of claims 1 to 41, wherein at least a portion of a side of the midsole (127) extends upwardly toward the side of the shoe sole (28) such that the midsole outer surface extends above the lowest point of the outer surface (39) of the foot of an intended wearer when in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded condition. 43. Shoe sole (28) according to one of claims 1 to 42, wherein an inner surface (30) of at least one side of the midsole (127) has at least a portion that conforms to the shape of the outer surface (29) of the foot of an intended wearer (27) when in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 44. Shoe sole (28) according to one of claims 1 to 43, wherein at least one side portion of an outer surface (31) of the outsole (128) is concavely rounded with respect to an intended wearer's foot position in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state. 45. Shoe sole (28) according to one of claims 1 to 44, wherein the outsole (128) extends into a lateralmost portion of the shoe sole (28) and at least a portion of the outer surface (31) of the outsole (128) in the lateralmost portion of the shoe sole (28) is concavely rounded with respect to an intended wearer's foot position in the shoe, viewed in a front plane cross-section when the shoe sole (28) is in an upright, unloaded state.