Energy translating platforms incorporated into footwear for enhancing linear momentum

Abstract

The present invention provides soles or platforms incorporated into footwear, preferably athletic footwear, designed to promote a more efficient running technique by an energy-translating sole comprising one or more foot-strike member, angular displacement member and balance-thrust member, as well as other conventional features. Systems and methods of the present invention promote more efficient running technique by facilitating foot-strike to occur at a point under and behind the runner's center of gravity. This may be accomplished, for example, by a foot-strike member, angular displacement member and balance-thrust member working cooperatively to displace the runner's center of gravity and translate gravitational, inertial and ground reaction forces, as well as muscular tension forces, into linear momentum.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/045,299, filed on Oct. 23, 2001, which claims priority to provisional application No. 60/242,742, filed on Oct. 23, 2000. The priority of the prior applications is expressly claimed and their disclosures are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to athletic shoe technology. More particularly, it relates to systems and methods for various forms of energy-translating soles, or platforms, which are incorporated into footwear and are designed to more effectively transfer gravitational, inertial and ground reaction forces into linear momentum thereby promoting a more efficient running technique.

[0004] 2. Description of the Related Art

[0005] Athletic shoe technology has undergone a revolution over the past thirty years, particularly in regards to improvements in running shoes, both for the professional and casual user. In general, the majority of advancements in running shoe technology have largely centered around support, shock absorption and energy efficiency. For example, U.S. Pat. No. 5,909,948 describes an athletic shoe sole having a lateral stability element to provide improved lateral support during heel-strike. U.S. Pat. Nos. 5,247,742 and 5,297,349 describe a cushioning sole for athletic shoes having a pronation control device incorporated into the midsole in order to increase the resistance to compression of the midsole from the lateral side to a maximum along the medial side, and U.S. Pat. No. 5,987,779 describes an athletic shoe having an inflatable tongue or bladder for a more secure fit.

[0006] A major focus in athletic shoe technology has centered on shock absorption. A number of patents describe various systems for shock absorption, such as air channels, miniature pumps, hydraulic systems, gas-filled bladders, elastomeric foam elements, pneumatic inflation devices and spring elements. The following are illustrative of such technologies: U.S. Pat. No. 5,598,645, U.S. Pat. No. 4,535,553, U.S. Pat. No. 5,325,964, U.S. Pat. No. 5,353,523, U.S. Pat. No. 5,839,209, U.S. Pat. No. 5,983,529 and U.S. Pat. No. 4,763,426.

[0007] Embodiments of the present invention are distinct from the athletic shoe technologies pertaining to additional support or shock absorption described above in that systems and methods of the present invention focus on locomotion efficiency.

[0008] There have been several shoe systems related to increasing energy efficiency during running, such as U.S. Pat. No. 4,358,902, which describes a thrust-producing shoe comprising a sole having fluid-filled cavities located in the heel and metatarsal portions with passageways interconnecting the fluid-filled cavities. As the heel cavity is compressed, fluid is forced through the passageways into the metatarsal cavities thereby providing shock absorption and forward thrust in the heel and metatarsal area.

[0009] U.S. Pat. No. 4,030,213 discloses a sporting shoe having an auxiliary sole member that is relatively thick under the toe portion and its outer surface is curved to form nearly a half circle at the forward extremity of the toe section and the rearward extremity at the ball of the foot is relatively flat. An additional embodiment describes a plurality of recesses within the sole of the shoe for housing a number of coil springs.

[0010] U.S. Pat. No. 4,506,460 describes a spring moderator for articles of footwear, wherein a high modulus moderator is positioned beneath the heel or forefoot with a cushioning medium beneath the moderator. The spring moderator operates to absorb, redistribute and store the energy of localized loads.

[0011] U.S. Pat. No. 4,936,030 provides an energy efficient running shoe having an energy-transmission mechanism in the heel portion of the sole to transmit the mechanical energy of heel impact to the storage/thrust mechanism in the front sloe portion, where it is stored and released during thrust. A number of embodiments are described having sophisticated systems employing lever arms, coils springs, hydraulic assemblies and the like for capturing and transferring mechanical energy.

[0012] U.S. Pat. No. 4,949,476 discloses a running shoe having a hard front sole for retaining gripping elements and, from the ball to the shank of the foot, an upwardly extending support cup on the outside of the shoe upper. The front sole extends into the shank portion of the shoe and covers a support wedge member. The wedge member extends from the ball of the foot to the shank and is progressively thicker towards the rear portion of the shoe. The wedge shaped member causes the foot to be brought into an extended position for emphasizing contact with the ground with the front outside ball region of the foot. This configuration serves to increase running efficiency by keeping the heel in an elevated position, which is the preferred attitude during sprinting.

[0013] U.S. Pat. No. 5,586,398 provides an article of footwear for more efficient running and walking wherein the contour of the outer sole at the heel is formed at a dihedral angle to the medial/forefoot portions in order to delay the instant of initial contact and thereby allow a longer length of foot flight and correspondingly longer stride length. An additional embodiment provides for friction management through materials selection, surface coatings, or surface treatments designed to affect friction across one or more interfaces between foot plantar surface and shoe insole.

[0014] U.S. Pat. No. 5,647,145 describes a sculptured sole for an athletic shoe comprising a plurality of forward support pads, rearward support lands, a layer of flexible resilient elastic material interconnecting various components, as well as a plurality of channels, grooves, slots and the like, which complement the natural flexing actions of the muscles of the heel, metatarsals and toes of the foot.

[0015] U.S. Pat. No. 5,680,714 discloses a trampoline effect athletic shoe having elastic return strips running across the sole of the shoe and supported above the bottom surface in a gap between the outsole and insole.

[0016] U.S. Pat. No. 5,829,172 relates to shoe soles of running shoes, particularly for 100 m sprints and the like. The object of the invention is to prevent the heel from touching the ground during running and thereby prevent a decrease in running efficiency. The sole comprises a thickly formed forefoot section for receiving spikes. A Reinforcing member provided in the ball region of the foot is integrated with reward-projecting medial and lateral ribs to form a wedge-shaped plane extending toward the heel. Medial and lateral ribs and reinforcing member form a wedge-shaped inclined plane extending form the ball to the arch of the foot, which serves to maintain the weight distribution of the runner over the ball of the foot and hold the heel of the foot in an elevated position.

[0017] U.S. Pat. No. 5,743,028 describes a spring-air shock absorption and energy return device for shoes in which a shoe heel insert is provided having a heel-shaped outer spring mechanism which serves as an internal spring housing wherein a plurality of compression springs are retained, and wherein the entire unit is filled with a pressurized gas and hermetically sealed.

[0018] U.S. Pat. No. 5,87,568 pertains to an athletic shoe wherein the sole has a rounded heel strike area and gently curved bottom that gradually thins towards the toe section to permit the runner to roll smoothly forward from the initial heel strike. Additional embodiments further provide for a shock-absorbing insert in the heel section.

[0019] U.S. Pat. No. 5,937,544 provides athletic footwear wherein the sole includes a foundation layer of semi-flexible material attached to the upper and defining a plurality of stretch chambers, a stretch layer and a thruster layer attached to the stretch layer such that interactions can occur between the foundation layer, stretch layer and thruster layer in response to compressive forces applied thereto so as to convert and temporarily store energy applied to regions of the sole by wearer's foot into mechanical stretching of the portions of the stretch layer into stretch chambers. The stored applied energy is thereafter retrieved in the form of rebound of the stretched portions of the stretch layer and portions of the thruster layer.

[0020] U.S. Pat. No. 6,006,449 and U.S. Pat. No. 6,009,636 relates to footwear having various forms of spring assemblies incorporated into the sole, which serve to absorb shock and transfer energy.

[0021] The foregoing and other known prior art have fundamental disadvantages in that they are not directed at improving efficiency by synchronizing the three basic phases of the human running cycle, seen illustrated in FIGS. 6A-6C with elements on the shoe that optimize momentum, efficiency, and fluidity of motion through the cycle. For example, prior art shoes place the wearer in a plantigrade stance, as shown in FIG. 7. Generally, a plantigrade stance is created between the balance of two points: one at the calcaneous and the other at the metatarsal/phalanges joints. Relative to the digitigrade stance provided through the novel embodiments of the present invention described below, plantigrade shoe systems are inefficient in that in subject the wearer of the shoe systems to greater breaking forces during running cycles.

[0022] Rather than hydraulic or pneumatic systems; mechanical spring and/or lever assemblies; resilient elastic bands; alteration of the heel-strike region; or reinforcing structures to maintain the heel in an elevated position, the present invention provides systems and methods that promote efficient running technique by providing a sole comprising a specially designed foot-strike member and balance-thrust member, which are integrated with a unique pivot and balance structure that displaces the wearer's center of gravity when running, thereby transferring gravitational, inertial and ground reaction forces, as well as muscular tension generation into linear momentum. Systems and methods of the present invention are an advance in the field of athletic shoe technology by providing a specialized sole design for redirecting the forces encountered during running into linear momentum, while reducing the shock and trauma to the body. The present invention provides novel footwear and components thereof for achieving a more efficient centering of mass that helps improve transfer of momentum energy to a stable platform for propulsion during toe-off (propulsion) phase of gait.

SUMMARY OF THE INVENTION

[0023] Systems and methods of the present invention provide energy-translating soles, or platforms, for footwear, preferably athletic footwear, designed to promote a more efficient running technique. In one aspect, promoting a more efficient running technique is facilitated by an energy-translating sole comprising one or more of the following features: at least one foot-strike member, one or more angular displacement members and at least one balance-thrust member, as well as other conventional features.

[0024] In another aspect, systems and methods of the present invention promote more efficient running technique by facilitating foot-strike to occur at a point under and behind the runner's center of gravity. This is accomplished by the foot-strike member, angular displacement member and balance-thrust member working cooperatively to displace the runner's center of gravity and translate gravitational, inertial and ground reaction forces, as well as muscular tension forces, into linear momentum.

[0025] In a further aspect, systems and methods of the present invention provide one or more foot-strike members, which may be situated in any location along the longitudinal axis (X axis) of the energy-translating sole with a front zone extending into the forefoot area and a rear zone optionally extending into the heel section. Foot-strike member may encompass the entire heel to forefoot sections, and/or any region there between. The medial and lateral margins of foot-strike member may generally follow the natural contours of the foot, and in embodiments wherein foot-strike member extends rearwardly to the heel, foot-strike member generally follows the contour of the heel.

[0026] In yet another aspect, angular displacement member is generally located forward of foot-strike member, and is generally positioned in the forefoot or metatarsal area of the foot. The front margins of angular displacement member may extend well into the toe section of sole with the rear margin optionally extending along the longitudinal axis well into the arch section of the sole. In a related aspect, various embodiments employ specially configured angular displacement members to suit particular running needs.

[0027] In another aspect, angular displacement member may have any number and/or sort of traction-related features, such as, but not limited to, grooves, channels, ribs, points, raised projections of any sort, and the like.

[0028] In still yet another aspect, angular displacement member is geometrically designed to provide a pivoting zone, preferably running transversely in the Z-axis between medial and lateral margins. Pivot zone may be located at or near the sesamoidal line along the longitudinal axis (X-axis) within angular displacement member depending upon the particular embodiment. Preferred embodiments of the present invention have pivoting zone encompassing the metatarsal region of the foot at or near the sesamoid bones of the first metatarsal head.

[0029] In a further aspect, systems and methods of the present invention provide one or more balance-thrust members, which generally encompass the toe section of the sole. Alternative embodiments may provide at least one balance-thrust member further comprising a plurality of traction facilitating members, such as spikes, teeth, ridges, grooves and the like. Medial and lateral margins of balance-thrust member generally follow the natural contours of the anatomical features of the foot, but the overall configuration and orientation of balance-thrust member varies with each particular embodiment.

[0030] In yet another aspect, the present invention provides a plurality of embodiments specifically designed for different running needs, which is partially dictated by the speed and distance involved. Each particular embodiment has a unique configuration and orientation of foot-strike member, angular displacement member and balance-thrust members to accommodate the unique biomechanical requirements of various types of running.

[0031] Other aspects of the present invention provide systems and methods to effectively displace the runner's center of gravity and translate gravitational, inertial and ground reaction forces into linear momentum. In another aspect, the present invention provides a platform that provides a rotational base for dissipating the shock of foot strike, thereby providing a more comfortable running shoe, which helps reduce the risk of injury associated with forceful foot strike.

[0032] These and other objects, advantages, and features of this invention will become apparent upon review of the following specification and accompanying drawings.

BRIEF SUMMARY OF THE DRAWINGS

[0033] FIG. 1A shows a conventional shoe illustrating general features of a running shoe typically found in the prior art.

[0034] FIG. 1B is a lateral perspective of the skeletal system of the human foot depicting the various anatomical features in relation to conventional footwear.

[0035] FIG. 2 shows a stylized plantar view of one embodiment of an athletic shoe sole of the present invention in spatial reference to the human foot.

[0036] FIG. 3 is a cross-sectional side view of an athletic shoe employing systems of the present invention.

[0037] FIG. 4A is an alternative embodiment designed for distance running.

[0038] FIG. 4B is an additional embodiment designed for mid-distance running, such as a 1500 m race.

[0039] FIG. 4C shows yet another embodiment specifically designed for short-distance sprints, such as a 100 m race.

[0040] FIGS. 5A-D illustrate the correlation of foot cycle, that is from foot-strike to angular displacement point, to angle 2 of redirection of energy into maximum linear momentum for and embodiment for short-distance sprints, such as a 100 m race (5A), mid-to-long distance sprints, such as a 800 m race (5B), mid-distance running, such as a 1,500 m race (5C) and long-distance running, such as jogging (5D).

[0041] FIGS. 6A-C illustrate three basic phases of the human running cycle.

[0042] FIG. 7 illustrates the center of mass of a runner achieved using conventional footwear versus the center of mass achieved of a runner using footwear according to the present invention.

[0043] FIG. 8 is a top view of the plantar surface of a sole unit according to the present invention.

[0044] FIG. 9 is the sectional view of the sole unit of FIG. 8 taken along line 9-9.

[0045] FIG. 10 is a top view of the plantar surface of a sole unit according to the present invention.

[0046] FIG. 11 is the sectional view of the sole unit of FIG. 10 taken along line 11-11.

[0047] FIG. 12 is a top view of the plantar surface of a sole unit according to the present invention.

[0048] FIG. 13 is the sectional view of the sole unit of FIG. 12 taken along line 13-13.

[0049] FIG. 14 is a top view of the plantar surface of a sole unit according to the present invention.

[0050] FIG. 15 is the sectional view of the sole unit of FIG. 14 taken along line 15-15.

[0051] FIG. 16 is a top view of the plantar surface of a sole unit according to the present invention.

[0052] FIG. 17 is the sectional view of the sole unit of FIG. 16 taken along line 17-17.

[0053] FIG. 18 illustrates the relationship of certain anatomical parts of the foot to a sole unit according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0054] It is believed that the advantages of the present invention arise from a more efficient, relative forward centering of mass of the runner during the running cycle. In contrast to the inherently inefficient centering of mass of conventional running shoes that places runners in a plantigrade stance during the foot-contact phase of the running cycle, the present invention places runners in a digitigrade stance that more optimally moves the center of mass of the wearer forward through repeated running cycles, as generally indicated in FIG. 7. Moving the center of mass forward of the position achieved in the plantigrade stance allows the counter-balance thruster unit to create a stable forefoot platform, enhancing propulsion, and a smoother transition from foot-strike to toe-off. The present invention also provides a platform for the foot that provides a rotational base for dissipating the shock of foot strike, thereby providing a more comfortable running shoe, which helps reduce the risk of injury associated with forceful foot strike.

[0055] The embodiments of the present invention all relate to a sole unit, such as sole unit 1211, for use in an item of footwear. In general terms, a sole unit is the whole or part of any portion of a shoe that is disposed between a foot of the wearer and the ground. More specifically, the sole unit portion may be the whole or part of the outsole, midsole, insole or combinations thereof. It may be a footwear insert, such as an orthotic. Specific example embodiments of sole units are described in more detail below.

[0056] As noted above, the novel sole units of the present invention are adapted to place the wearer in a "digitigrade" stance. Generally, two points in the forefoot area define a "sesamoidal line": one at about the metatarsal/phalanges joints and one at about a more distal (forward) area. In the digitigrade stance, the sole unit elevates the metatarsal/phalanges joints, including the sesamoid points as shown in FIG. 18. The degree of elevation has a direct relation to the rotation/displacement of the wearer's center of mass: the higher the elevation (within anatomical/biomechanical limits), the greater the rotation/displacement, which correspondingly allows smoother transition of mechanics from foot-strike to toe-off. The rotation possible with a digitigrade stance also spreads the force of foot strike over the time and surface over which the rotation occurs, thereby dissipating impact forces relative to conventional shoes, which do not have a mechanism for a digitigrade stance and rotation/counterbalance, as described below.

[0057] FIG. 18 shows the general positioning of the sole unit relative to a foot of a wearer. It can be seen that the heel 3 of the foot is elevated relative to the sesamoidal region 5. For certain shoes such as running shoes, street, shoe, etc. it will be desirable to provide an in-fill material under some or all of the raised area to support the foot. The in-fill could be in the form of a cushioning material and/or outsole, for example. On the other hand, in the case of a track shoe, where a forefoot foot strike dominants during Use, little or no in-fill need be provided.

[0058] In embodiments of the present invention, an angular displacement member in the area of the metatarsal/phalanges joints achieves the digitigrade stance and a balance-thrust member in a more forward area. In one possible embodiment, the digitigrade stance is based at least in part on a position of balance about a line--"the sesamoid line"--substantially defined by the sesamoid apparatus and the head of the fifth metatarsal. In the various embodiments of sole units described herein, the sole units are adapted to allow the wearer's foot to pivot forward or aft around such a line.

[0059] The balance-thrust member is a counterbalance or stop to help control the forward motion and balance of the wearer, i.e., help keep the wearer from falling forward following the angular forward pivot of the angular displacement member. In this regard, the balance-thrust member may be provided at one or more points forward of the metatarsal bones, preferably at points in a line--the "balance-thrust line--substantially defined by the first distal phalange to about at least the third distal phalange.

[0060] Accordingly, a digitigrade support system according to the present invention: (1) enables the center of mass to move more forwardly during the propulsive phase relative to the position of center of mass sustained by a plantigrade type of support system during the same phase, as illustrated in FIG. 7; or (2) enables the center of mass to move forward more quickly than it would move in a plantigrade support system. In either case, there is direct influence on the forward rotation/displacement of the center of mass, and the digitigrade system helps reduce breaking forces, resulting in greater inertial forces.

[0061] While the invention may be embodied in different forms to achieve more optimal centering of mass, the specific embodiments shown in the figures and described herein are presented with the understanding that they are exemplary of the principles of the invention and are not intended to limit the invention to that specifically illustrated and described herein. FIG. 1A shows a generic form of footwear comprising an upper, indicated generally as 10, and a sole unit which generally may comprise (i) a midsole for energy absorption and/or return; (ii) an outsole material for surface contact and abrasion resistance and/or traction; or (iii) a single unit providing such midsole or outsole functions. For example, the sole unit shown in FIG. 1A includes a midsole 12, an outsole 114 and an insole 16 on the interior lower surface of the footwear. The sole unit can cover some or all of the area of the supported foot.

[0062] As is well known in the art, the sole unit may include resilient elements that provide cushioning against shock. They may also be of a nature that provides energy return (in essence, spring) upon impact. For convenience, unless otherwise expressly or contextually indicated, "resilient element" refers to an element with either energy absorption and/or return functionality. One or more resilient elements may be included in a sole unit at locations where cushioning may be needed. For example, the rearfoot portion of the sole unit would typically require cushioning, and resilient element may be located there. Similarly, forefoot section may include one or more resilient elements.

[0063] The shoe illustrated in FIG. 1A has a conventional shoelace 18 engaged in eyelets 20. Upper 10 is partially split at the central, top portion of the footwear wherein lies some form of closure system 24, such as a conventional tongue. Collar 22 is provided to support the foot and/or ankle. Generally speaking, conventional shoes may be divided into heel (A), arch (B), ball or forefoot (C) and toe (D) regions. These elements of the footwear illustrated in FIG. 1A are generally conventional. Athletic shoes of the present invention comprise such conventional features, as well as others in conjunction with a specially designed sole system. FIG. 1B is a lateral perspective of the skeletal system of the human foot wherein the heel (A), arch (B), ball (C) and toe (D) regions of a conventional shoe align, in a general sense, with the anatomical structures depicted therein.

[0064] FIGS. 2-3 show a stylized plantar view of one embodiment of an athletic shoe sole, namely an energy-translating sole 100 of the present invention, in spatial reference to the human foot. FIG. 3 depicts a cross-sectional side view of the same embodiment. In certain broad aspects, systems and methods of the present invention provide an energy-translating sole unit, that is incorporated into shoes, preferably athletic shoes, including one or more of the following features: at least one foot-strike member 102, one or more angular displacement members 104, with its apex falling at or near the sesamoid apparatus medially and extending under lesser metatarsal heads laterally, and at least one balance-thrust member 106. As illustrated, there may be considerable overlap of the various members 102, 104, 106, but in alternative embodiments, members 102, 104, 106, may not necessarily have appreciable overlap. In general, systems and methods of the present invention promote more efficient running technique by facilitating foot-strike to occur at a point under and behind the runner's center of gravity. Foot-strike member 102, angular displacement member 104, and balance-thrust member 106 work cooperatively, creating a stable forefoot platform and smoother transition from footstrike to toe-off, and to displace the runner's center of gravity and translate gravitational, inertial and ground reaction forces, as well as muscular tension forces, into linear momentum.

[0065] As will be described in greater detail below, systems and methods of the present invention provide a plurality of embodiments specifically designed for different running needs, which is partially dictated by the speed and distance involved. The particular embodiment depicted in FIGS. 2 and 3 comprises footwear designed for running a mid-to-long distance sprint, such as a 400 m race. It is understood that the embodiment depicted in FIGS. 2 and 3 are merely illustrative of the general principles of the present invention and are not meant to be limiting in any respect.

[0066] Foot-strike member 102 is generally made of any conventional dense, semi-deformable, wear resistant material, such as synthetic polymers and plastics of any sort, having sufficient compliance and resiliency features to adequately absorb a relative portion of impact forces imparted to the shoe and body of the runner upon initial contact with a supporting surface. Various embodiments of the present invention may employ materials that are more suitable for that particular application. For example, an embodiment for distance running may utilize a material for foot-strike member 102 having greater indices of compliancy and resiliency than an embodiment for sprinting. Foot-strike member 102 comprises a front zone 112 (FIG. 3) extending towards toe section 126 (FIG. 2) and a rear zone 114 extending towards heel section 120. In preferred embodiments, front zone of foot-strike member 112 is arcuately formed to follow the natural anatomical features of the foot, but alternative embodiments also include additional configurations and foot-strike member rear zone 114 generally follows the anatomical margins of the foot, such as the arch and heel. Foot-strike member 102 may be situated in any location along the longitudinal axis (X axis) of sole 100 with front zone 112 extending into forefoot section 124 rear zone 114 extending into heel section 120 and may encompass the entire heel 120 to forefoot 124 sections, and/or any region there between. The medial 108 and lateral 110 margins of foot-strike member 102 generally follow the natural contours of the foot, and in embodiments wherein foot-strike member 102 extends rearwardly to the heel, foot-strike member 102 generally follows the contour of the heel.

[0067] Foot-strike member 102 may be of a singular uniform molded composition or alternatively, be provided in a layered or composite configuration. Plantar surface 116 of foot-strike member 102 may be integral with and/or adjacent to any conventional outsole having any number and/or type of traction-related features, such as, but not limited to, grooves, channels, ribs, points, raised projections of any sort, and the like. Furthermore, foot-strike member 102 may further comprise any conventional pneumatic and/or hydraulic cells, bladders, chambers and the like to further facilitate and control shock absorption.

[0068] The configuration, dimensions and preferred construction materials of foot-strike member 102, as well as angular displacement member 104 and balance-thrust member 106, is largely dependent upon the particular embodiment. The embodiment presented in FIGS. 2 and 3 show foot-strike member 102 having a generalized elliptical form having a thickness ranging from 0.5 to 10 cm, with front zone 112 tapering towards, and transitioning with and/or into angular displacement member 104 and rear zone 114 tapering and transitioning with and/or into one or more support bases 158. Naturally, the tapered ends of foot-strike member may fall outside the provided ranges. Support base 158 may be may be integral with and/or adjacent to any conventional outsole having any number and/or type of traction-related features, such as, but not limited to, grooves, channels, ribs, points, raised projections of any sort, and the like.

[0069] Angular displacement member 104 is located forward, towards forefoot 124 and toe regions 126, of foot-strike member and is generally positioned in the forefoot or metatarsal area 124 of the foot. Front zone 128 of angular displacement member 104 is generally arcuately designed and may extend well into toe section 126 of sole 100 and rear zone 130 of angular displacement member 104 may extend along the longitudinal axis well into arch section 122 of sole 100. Alternative embodiments envision angular displacement member 104 being more compact, that is, encompassing less surface area, and more discreetly positioned over the metatarsal and/or metatarsal-phalanges areas of the foot. Dorsal surface 134 of angular displacement member 104 is integrated with or fixedly adhered to support base 158. Plantar surface 132 of rear zone 130 of angular displacement member 104 is fixedly integrated with and/or adhered to dorsal surface 118 of front tapering zone 112 of foot-strike member 102, such that a relatively smooth transition between foot-strike 102 and angular displacement 104 members is achieved and a strong, permanent bond or integral component is provided. In preferred embodiments, plantar surface 132 of angular displacement member 104 may have any number and/or sort of traction-related features, such as, but not limited to, grooves, channels, ribs, points, raised projections of any sort, and the like. Medial 136 and lateral 138 margins of angular displacement member 104 generally follow the natural anatomical profile of the foot and, preferably, flow smoothly into respective medial 108 and lateral 110 margins of foot-strike member 102.

[0070] Angular displacement member 104 is geometrically designed to provide a pivoting zone 140, preferably running transversely in the Z-axis between medial 136 and lateral 138 margins. Preferred embodiments of the present invention have pivoting zone 140 in the forefoot 124 region, and more preferably encompassing the metatarsal region of the foot at or near the sesamoidal line. Pivot zone 140 may be located anywhere along the longitudinal axis (X-axis) within angular displacement member 104 depending upon the particular embodiment. Pivot zone 140 may be variously shaped, but in preferred embodiments, is arcuately formed to follow the natural curvature and anatomical structures of the foot, such as, but not limited to, the metatarsal-phalanges articulations, as well as accommodate and exploit the natural lateral to medial rolling of the foot during running. Systems and methods of the present invention are designed to promote more efficient running technique by facilitating foot-strike to occur at a point under and behind the runner's center of gravity. Foot-strike member 102, angular displacement member 104, and balance-thrust member 106 work cooperatively, creating a stable forefoot platform and smoother transition from footstrike to toe-off, and to displace the runner's center of gravity and translate gravitational, inertial and ground reaction forces, as well as muscular tension forces into linear momentum.

[0071] Front zone of angular displacement member 128 is integral with, and/or fixedly adhered to, rear section 148 of balance-thrust member 106 in an overlapping or abutting manner. Balance-thrust member 106 is located forward (i.e., towards toe section 126) of angular displacement member 104 and generally encompasses the front part of forefoot section 124 and all of toe section 126 of sole 100. Depending upon the particular embodiment, balance-thrust member 106 may be formed of semi-deformable material or essentially non-deformable material, but in general, comprises a material having relatively less compliancy and resiliency than that of foot-strike member 102, such as conventional synthetic polymers and/or plastics, such that significant levels of kinetic and mechanical energy are not overly dampened by deformation of the material. In select embodiments, such as depicted in FIGS. 2 and 3, as well as others, balance-thrust member 106 may be provided with a plurality of traction-facilitating elements projecting from plantar surface 150, such as, but not limited to, spikes, teeth, cleats, ridges and the like. Such traction-facilitating elements may be fixedly connected to, and/or releasably integrated with, and/or integrally formed from balance-thrust member 106 by any conventional methods. Choice of construction materials for balance-thrust member 106 should have sufficient hardness, as determined by conventional methods, to retain traction-facilitating elements and effectively transmit forces from sole 100 to supporting surface and vice versa.

[0072] Front zone 146 of balance-thrust member 106 extends up to, and in select embodiments, extends beyond, the phalanges distal margin of the first metatarsal bone. Front zone 146 of balance-thrust member 106 ends in a termination point 160, which may be in the form of traction facilitating members, such as spikes, teeth, ridges, grooves and the like, depending upon the particular embodiment. Termination point 160 may be variously located long the longitudinal axis (X-axis) of sole 100. For example, FIG. 2 depicts a shoe designed for mid-to-long distance sprinting and has termination point 160 at a downward-projecting angle and extending somewhat beyond the forward perimeter of support base 158 and upper 10, but other embodiments, such as a distance shoe and/or jogging shoe, may have termination point extend even further beyond the forward perimeter of support base 158 and upper 10 and not have as pronounced a downward projecting angle. Medial 154 and lateral 156 margins of balance-thrust member 106 generally follow the natural contours of the anatomical features of the foot. As with other aspects of the present invention, plantar surface 150 area of balance-thrust member varies with each particular embodiment. For purposes of example, select embodiments, such as in FIG. 2, lateral margin 156 may define a more focused balance-thrust member, that is, delineate plantar surface 150 area of balance-thrust member 106 to encompass the first through fourth metatarsal-phalanges areas of the foot, such that horizontal propulsive forces at toe-off are effectively focused on the most relevant parts of the foot.

[0073] FIGS. 4A-C depict various embodiments of the present invention. As previously mentioned, systems and methods of the present invention are variously configured to accommodate different types of running, such as, but not limited to, long-distance running or jogging (FIG. 4A), intermediate distances, such as 1,500 m racing (FIG. 4B), mid-to-long distance sprints, such as 400 m racing (described in detail above and in FIGS. 2 and 3), and short-distance sprints, such as 100 m racing (FIG. 4C).

[0074] Kinesiological analysis of running has demonstrated different types and speeds of running involve different biomechanics. During a running cycle involving a heel-strike, such as jogging, various portions of the foot undergo a number of movements and are exposed to various forces. When foot-strike, that is heel-strike, is initiated, the foot is in supination and as contact progresses pronation permits partial absorption of impact forces. As the foot transitions from mid-support to takeoff, resupination, or transfer to the lateral ball portion of the foot occurs as the foot becomes a rigid lever. The continuous motion transfers from lateral to the medial ball of the foot as the foot accelerates through toe-off. In contrast, during sprinting, the ground strike occurs in the forefoot or metatarsal area of the foot and the point of impact tends to be under or slightly behind their center of gravity. As a result, this form of running has less of the deceleration phase associated with heel-strike running and propels the body mass forward more efficiently.

[0075] Systems and methods of the present invention provide a range of embodiments to accommodate these biomechanical requirements. In general, the angle of displacement is directly related to the type and speed of running. In short, the faster the running speed, the higher the angle of displacement, as depicted by pivot zone profile 170, and the more proximal to the toe region 126 the pivot zone 140 is oriented. These salient points are most clearly illustrated by contrasting respective foot-strike 102', 102'", angular displacement 104', 104'" and balance-thrust members 106', 106'" in a distance-running embodiment ("running shoe"--FIG. 4A) versus a short-sprint embodiment ("sprinting shoe"--FIG. 4C). As clearly illustrated, the distance-running shoe presented in FIG. 4A has a more extensive foot-strike member 102', with rear zone 114' of foot-strike member 102' extending to completely encompass heel section 120, and is substantially thicker to more effectively absorb impact forces, whereas the embodiment designed for sprinting illustrated in FIG. 4C, has a limited foot-strike member 102'" with rear zone 114'" of foot-strike member 102'" extending from the forward section of the arch region 122 into the forefoot region 124. Foot-strike member 102'" of the embodiment designed for sprinting is oriented to accommodate a running style wherein initial contact with the supporting surface is predominantly in the forefoot area of the foot. Angular displacement member 104' of the distance shoe has a lower pivot area profile 107' as compared to the angular displacement member 104'" of the sprinting shoe's pivot area profile 170'". Additionally, angular displacement member 104" with apex 172 for the running shoe has a larger radius in relation to angular displacement 104'" with member apex 176 for the sprinting shoe. This allows the sprinting to maintain a higher angle of displacement and faster rotation. Furthermore, balance-thrust member 106' of running shoe encompasses a greater surface area of toe section 126, and in some embodiments, front zone 160' may extend beyond toe section of upper, whereas, balance-thrust member 106'" of sprinting shoe encompasses comparatively less surface area.

[0076] During a running cycle, as the initial foot-strike makes contact with the supporting surface, there is a certain amount of supination and the foot is slightly ahead of the center of mass, which serves to minimize deceleration forces and to preserve linear forward momentum. The talocalcaneal, or subtalar, joint plays a major role in converting the rotary forces of the lower extremity into forward motion. In operation, systems and methods of the present invention build upon these natural movements by assisting foot-strike to occur at a point under and behind the center of gravity.

[0077] Following contact with the surface, the support phase is initiated, wherein the runner's body mass is fully supported. As the knee flexes to absorb impact forces and support the runner, the ankle plantar flexes and the subtalar joint pronates, causing heel pronation. Heel pronation permits absorption of compressive shock forces, torque conversion, adjustment to uneven ground contours and maintenance of balance. Eccentric tension in the posterior tibialis, soleus and gastrocnemius muscles cause deceleration of subtalar joint pronation and lower extremity internal rotation. Pronation reaches its maximum during this time and resupination is initiated to permit the foot to pass through its neutral position at the midpoint of the support phase. When the runner's center of mass is at its lowest position, a maximum vertical force is actively generated and transmitted to the supporting surface by the muscles and is often referred to as the active vertical force peak. This active vertical force peak typically reaches 2 to 8 times body weight, depending on the speed of the runner. It is during the support phase that angular displacement member 104, and more particularly, pivot region 140, engage supporting surface, initiating displacement of the runner's center of gravity. Systems and methods of the present invention serve to minimize the support phase, thereby conserving biomechanical energy by limiting energy lost to the supporting surface. Furthermore, embodiments of the present invention reduce shock and trauma to the runner by redirecting gravitational and inertial forces into linear momentum.

[0078] The support phase continues until the heel begins to rise into takeoff during the recovery phase. Generally speaking, the recovery phase is the stage of running in which muscular tension exerts vertical and horizontal forces to the support surface to propel the runner forward. During this time the foot converts from a shock-absorbing structure to a rigid lever for forward propulsion, which is largely due to changes in position of the subtalar and midtarsal joints, and in particular, supination of the subtalar joint. As the knee joint extends, the lower extremity rotates externally, the calcaneus inverts, the midtarsal joint locks, and the foot becomes a rigid lever. The propulsive force is a thrust backward and downward resulting from a combination of hip extension, knee extension and ankle plantar flexion. During the recovery phase, the rotational movement of the runner's foot undergoes a second rotational movement as the runner rolls through angular displacement and balance-thrust members 104, 106, respectively, incurring greater angular acceleration and thereby further displacing the runner's center of gravity forward and translating gravitational, inertial, ground reaction, and muscular tension forces into linear momentum.

[0079] These principles are more clearly presented in FIGS. 5A-D, which illustrate the correlation of a foot cycle, herein defined as being from initial foot-strike to angular displacement point, to angle 2 of redirection of energy into maximum linear momentum. In general, the angle 2 of displacement required for maximal redirection of energy is directly related to the type and speed of running and the faster the running speed, the greater the angle of displacement becomes. For example, embodiments designed for short-distance sprints, such as a 100 m race (FIG. 5A) have a comparatively low foot cycle radius (r), whereas embodiments designed for long-distance running (FIG. 5D) have a relatively large foot cycle radius (r'"). Furthermore, foot cycle radius (r) is inversely proportional to the angle 2 of redirection of energy. In other words, embodiments designed for short-distance sprinting (FIG. 5A) require a larger angular displacement profile 170.

[0080] Further example sole units according to the present invention are illustrated in FIGS. 8-17.

[0081] FIG. 8 generally shows the plantar side of a sole unit 811 formed of a rigidifying element of a substantially rigid nature, such as a substantially rigid plate 813, that may be disposed under at least a forefoot of a wearer. The sole unit is intended for use in a left shoe, as are all other sole units of FIGS. 8-17.

[0082] As used in this document, "substantially rigid" means at least rigid enough to facilitate a forward pivoting about the sesamoidal line while maintaining the sesamoid apparatus elevated relative to the portion of the foot that is forward of the sesamoidal line.

[0083] Preferably, the rigidifying element 813 extends between at least the sesamoidal line 817 and the balance-thrust line 806. The rigidifying element provides a platform for facilitating the digitigrade stance and rotation about the sesamoidal line. Preferably, it should be contoured on the top and/or bottom surface to conform to the foot and/or to facilitate placement of the foot in the digitigrade stance to provide rotation about the sesamoidal line, in conjunction with the angular displacement member. The rigidifying element may also extend rearward of the sesamoid line 817 to the heel. In addition to plates, the rigidifying element may be in the form of elongated bars, rods, fibers, and other such elements that are capable of creating a substantially rigid zone spanning between at least the sesamoidal line and the balance-thrust line.

[0084] A rigidifying element may be made from carbon fiber, wood, fiberglass, nylon, plastics, metal, fiberglass, and other such materials known to persons skilled in the art.

[0085] The sole unit 811 includes an angular displacement member 804, that is preferably disposed substantially along or about the sesamoidal line. The angular displacement member 804 on sole unit 811 may be formed in a continuous line 817 or in one or more separate sections along or about the sesamoidal line or a portion of such line. It may be a straight or curvilinear line, so long as some aspects coincide on or about the sesamoidal line. For example, curvilinear aspects could follow natural flexural axes of the foot.

[0086] Notably, the angular displacement member 804 need only occupy such points along or about the sesamoidal line to enable the foot to pivot around the line. The angular displacement member may be made of any material that will provide such pivoting in relation to adjacent or surrounding material.

[0087] The sole unit 811 also includes a balance-thrust member 806. As earlier noted, a balance-thrust member is disposed along a line forward of the angular displacement member, and it is defined preferably by the first distal phalange and the third distal phalange. The balance-thrust member is disposed at the forward end of the pivoting zone and structurally acts to interrupt and counterbalance the rotational effect provided through the angular displacement member.

[0088] FIG. 9 is a cross-section of sole unit 811 taken along line 9-9 in FIG. 8. It shows that angular displacement member 804 and balance-thrust member 806 are projecting away from the surface of plate 813. The relative height of the angular displacement member raises the sesamoid apparatus and enables the wearer's foot to pivot around the sesamoidal line.

[0089] Angular displacement member 804 and balance-thrust member 806 may be made of a firm or substantially rigid material or semi-resilient material or have a structure that imparts such properties. In any case, the angular displacement member should be configured to allow smooth and even pivoting action. In the case of the balance-thrust member, it should have sufficient firmness or resistance to serve as a check on the rotation imparted by the angular displacement member.

[0090] In FIG. 8, the angular displacement member and balance-thrust member are shown as discrete elements associated with sole unit 811. The angular displacement member and balance-thrust member may be directly affixed to other elements of the sole unit but do not necessarily need to be. For example, they may be free of any direct connection to other material but held in position by adjacent, abutting material, such as midsole. Alternatively, the members may be integrated into a sole unit having a unitary or monolithic structure. For example, using known molding techniques, a sole unit may be formed to integrally include the rigidifying member, angular displacement member, and/or balance-thrust member. In further illustration, the angular displacement member and/or balance-thrust member could be formed in a monolithic or unitary piece of material, with the members having a higher durometer or density or thickness relative to adjacent material such that pivoting and counterbalancing may occur.

[0091] The sole unit of FIG. 8, and the other figures, may include one or more layers or regions of an in-fill material, such as a cushioning material 815 that the displacement member and/or balance-thrust member are adjacent to, covered with, or otherwise integrated with, in whole or part. Such materials may help provide a pivotable configuration for the angular displacement member 804. The in-fill may extend to the heel, depending on comfort needs and the type of the athletic event for which the shoe is intended. From the teachings herein, persons skilled in the art will be able to determine appropriate coverage and thickness for particular applications without undue effort.

[0092] In one example embodiment, a shoe includes an upper associated with a substantially rigid plate, such as a thin, contoured carbon fiber plate 813. A standard foam or rubber midsole is disposed under the plate. An angular displacement member is disposed along or about a sesamoidal line. The angular displacement and the balance-thrust member are integrated into the midsole. A standard rubber outsole is disposed under the midsole. The angular displacement member and balance-thrust members are made of a firmer material than the relatively compliant material of the midsole. The angular displacement member in association with the substantially rigid plate places the foot in a digitigrade stance with rotation around the sesamoidal line.

[0093] FIG. 10 shows another possible embodiment of a sole unit 1011 according to the principles of the present invention. A plurality of substantially rigid discrete elements are disposed along the sesamoidal line and/or the balance-thrust line to provide the angular displacement member and/or the balance-thrust member. In one variant of this embodiment, the discrete elements are a plurality of spikes 1021 or traction elements for a running track surface. This embodiment is otherwise generally similar to the sole unit of 811. Preferably, the angular displacement member and balance-thrust member are disposed on a substantially rigid plate 1013. FIG. 11 shows a cross-section of the sole unit of FIG. 10 taken along line 11-11 in FIG. 10. As illustrated in FIG. 11, the discrete elements 1021 project downwardly from the sole unit so that they support the wearer in a digitigrade stance. Plate 1013 unit may also extend close to or all the way to the heel, consistent with conventional track shoe design. In other possible embodiments, the length of the sole unit may cover the foot to a lesser degree depending on the intended purpose of the shoe. The sole unit 1011 may optionally include some cushioning material or other in-fill material 1015, as described above.

[0094] FIG. 12 shows a plantar view of another possible embodiment of a sole unit 1211 according to the principles of the present invention. The sole unit 1211 includes a first substantially rigid plate 1213A, which is disposed generally on a lateral side of the sole unit. A second substantially rigid plate 1213B is disposed on a medial side of the sole unit. The plates are adjacent or closely separated along an arcuate line 1217 that at least in part coincides with the sesamoidal line. The plates mass material to define the angular displacement member 1204 and balance-thrust member 1206, as indicated in FIG. 13, which is a sectional view of sole unit 1211 along line 13. For a wearer having a normal foot strike profile, the foot would normally land on the heel and roll to plate 1213A and then to plate 1213B. Accordingly, plate 1213A is preferably adapted for cushioning and plate 1213B is relatively firmer for propulsion.

[0095] FIG. 14 shows a sole unit 1411 with an angular displacement member 1404 comprising a plurality of generally parallel rib elements 1422 that are oriented substantially parallel to the longitudinal axis of the sole across the sesamoidal line. The rib elements may be substantially rigid, or may be less compliant than adjacent rearward or forward materials, to facilitate rotation about the sesamoidal line. FIG. 15 is sectional view of sole unit 1411 taken along line 15-15. As illustrated in FIG. 15, the ribs 1422 project downwardly from the sole unit so that they support the wearer in a digitigrade stance. The ribs also have an arcuate profile to facilitate pivoting. A fill-in material 1415 may be included in the sole unit, as per other embodiments.

[0096] FIG. 16 shows a sole unit 1611 with a laterally disposed balance-thrust member 1606 on the lateral and/or medial side of a sole unit. This location may be in addition to or an alternative the balance-thrust members of the earlier embodiments. The balance-thrust member 1606 works in conjunction with an angular displacement member, as described above. A laterally disposed balance-thrust member may be used in shoes intended for lateral cutting movements, such as basketball, soccer, and tennis. FIG. 17 shows a cross-section taken along line 17-17 of the sole unit 1611 of FIG. 16. Preferably, as in other embodiments, this embodiment of a sole unit has the balance-thrust member disposed on a substantially rigid plate 1613.

[0097] While the sole units of the foregoing embodiments may be shown isolated from an entire shoe or sole, from the following details, persons skilled in the art will be capable of integrating the disclosed sole unit into a complete shoe or sole using known techniques.

[0098] While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to various changes and modification as well as additional embodiments and that certain of the details described herein may be varied considerably without departing from the basic spirit and scope of the invention.

Claims

What I claim:

1. A shoe having a sole unit, the sole unit comprising: a rigidifying element disposed between at least a sesamoidal line and a balance-thrust line; an angular displacement member disposed at the sesamoidal line; and a balance-thrust member disposed at a balance thrust line, the angular displacement member and balance thrust member being positioned and adapted so that when both members are in contact with ground, the sesamoid apparatus of the wearer's foot is elevated with respect to the digits, placing the wearer in a digitigrade stance during at least a substantial portion of the support-propulsive phases of the gait cycle.

2. A shoe according to claim 1 wherein the rigidifying element comprises a plate.

3. The shoe according to claim 1 wherein the plate has a contoured surface to facilitate rotation of the foot about the sesamoidal line.

4. The shoe according to claim 2 wherein the plate comprises carbon fiber.

5. The shoe according to claim 1 wherein the plate extends to a heel portion of the sole unit.

6. The shoe of claim 2 wherein the angular displacement member comprises a semi-deformable material and has relatively less compliancy and resiliency than that of a rearwardly adjacent foot-strike member.

7. The shoe of claim 2 wherein the angular displacement member comprises an essentially non-deformable material.

8. The shoe of claim 1 wherein the angular displacement member comprises a rigid material that is disposed along a sesmoidal line and has relatively less rigid material disposed forward or rearward of the sesamoidal line.

9. The shoe of claim 1 wherein the angular displacement member comprises a plurality of rib elements oriented along the sesamoidal line to facilitate fore-aft pivoting of the foot of a wearer about the sesmoidal line.

10. The shoe of claim 1 wherein the sole unit includes a balance-thrust member disposed generally on a lateral or medial side of the sole unit in a forefoot portion of the sole unit.

11. A method of making a shoe comprising: providing a sole unit, the sole unit comprising: a rigidifying element disposed between at least a sesamoidal line and a balance-thrust-line; an angular displacement member disposed at the sesamoidal line; and a balance-thrust member disposed at a balance thrust line, the angular displacement member and balance thrust member being positioned and adapted so that when both members are in contact with ground, the sesamoid apparatus of the wearer's foot is elevated with respect to the digits, placing the wearer in a digitigrade stance during at least a substantial portion of the support-propulsive phases of the gait cycle; providing an upper for covering at least a portion of a top surface of a wearer's foot; and physically associating the sole unit with the upper.

12. A sole unit for a shoe comprising: a rigidifying element disposed between at least a sesamoidal line and a balance-thrust line; an angular displacement member disposed at the sesamoidal line; and a balance-thrust member disposed at a balance thrust line, the angular displacement member and balance thrust member being positioned and adapted so that when both members are in contact with ground, the sesamoid apparatus of the wearer's foot is elevated with respect to the digits, placing the wearer in a digitigrade stance during at least a substantial portion of the support-propulsive phases of the gait cycle.

13. A sole unit according to claim 12 wherein the rigidifying element comprises a plate.

14. A sole unit according to claim 13 wherein the plate has a contoured surface to facilitate rotation of the foot about the sesamoidal line.

15. A sole unit according to claim 12 wherein the plate extends to a heel portion of the sole unit.

16. The shoe of claim 1 wherein the angular displacement member comprises a section of midsole material and the rigidifying element.

17. The shoe of claim 1 wherein the angular displacement member comprises a section of midsole material and the rigidifying element, the section of midsole material being disposed substantially above the rigidifying element.

18. The sole unit of claim 12 wherein the angular displacement member comprises a section of midsole material and the rigidifying element.

19. The shoe of claim 12 wherein the angular displacement member comprises a section of midsole material and the rigidifying element, the section of midsole material being disposed substantially above the rigidifying element.

20. The shoe of claim 12 wherein the angular displacement member comprises a section of midsole material and the rigidifying element, the section of midsole material being disposed substantially above the rigid plate and the sole unit including a section of outsole materials disposed below the rigidifying element.

21. A shoe having an upper and a foot supporting member, the foot supporting member comprising: a substantially rigid member having a dorsal surface and a plantar surface; the plantar surface having an angular displacement member comprising a convex portion and a forwardly disposed balance-thrust member comprising a concave portion, the concave portion extending forward past the tips of the digits and terminating distally at a downwardly projecting balance-thrust member, the convex portion and the concave portion cooperating to accommodate the wearer in a digitigrade stance during at least a substantial portion of the support-propulsive phases of the running cycle.

22. A shoe according to claim 21 further comprising the plantar surface convex includes a curved angular displacement surface below the sesamoid apparatus of the first metatarsal phalangeal joint and defining a first axis of rotation of the foot.

23. A shoe according to claim 22 further comprising the balance-thrust member defining a second axis of rotation of the foot forward of the wearer's foot.

24. A shoe according to claim 22 further wherein curved angular displacement surface and balance thrust member are positioned so that when both are in contact with ground, the sesamoid apparatus is elevated with respect to the digits.

25. A shoe according to claim 21 further comprising a foot strike member adjacent the convex surface.

26. A shoe according to claim 21 further comprising the dorsal surface including a concave portion having a curvature selected to support the digits of the wearer's foot in a dorsiflexed position relative to the metatarsals.

27. A shoe having an upper and a foot supporting member, the foot supporting member comprising: a substantially rigid member having a dorsal surface and a plantar surface; the plantar surface having a convex portion and an adjacent concave portion, the concave portion extending forward past the tips of the digits and terminating distally at a downwardly projecting balance-thrust member; the plantar surface convex portion including a curved angular displacement surface below the sesamoid apparatus of the first metatarsal phalangeal joint and defining a first axis of rotation of the foot; and, the balance-thrust member defining a second axis of rotation of the foot forward of the wearer's foot.

28. A shoe having an upper and a sole member, the sole member comprising: a dorsal surface and a plantar surface; the plantar surface having an angular displacement member and a forwardly disposed balance-thrust member, the angular displacement member and the balance-thrust member cooperating to accommodate the wearer in a digitigrade stance during at least a substantial portion of the support-propulsive phases of the running cycle.

29. A shoe according to claim 28 wherein the angular displacement is disposed at least in part below the sesamoid apparatus of the first metatarsal phalangeal joint and defining a first axis of rotation of the foot.

30. A shoe according to claim 28 wherein the angular displacement has a convexly curved surface, the angular displacement member and the balance-thrust member being positioned so that when both are in contact with ground, the sesamoid apparatus is elevated with respect to the digits.

31. A shoe according to claim 28 further comprising a foot strike member rearwardly adjacent the angular displacement member.

32. A shoe according to claim 28 wherein the shoe includes a sole member comprising a substantially rigid material having a plantar surface; the plantar surface having the angular displacement member disposed thereon.

33. A shoe according to claim 28 wherein the shoe includes a foot supporting member comprising a substantially rigid member having a dorsal surface and a plantar surface; the plantar surface having the angular displacement member disposed thereon and the dorsal surface above the plantar surface having a concave shape for receiving at least a portion of the forefoot.

34. A sole member for a shoe comprising: a foot strike member, an angular displacement member, and a balance-thrust member, the aforesaid members cooperating during at least a portion of the support-propulsive phases of the running cycle to facilitate linear momentum, the angular displacement member being positioned at least in the metatarsal area of a foot and substantially underlying at least an area under the sesamoid apparatus of the first metatarsal, the balance-thrust member being located forward of the angular displacement and is at least in an area underlying or ahead of the distal phalanges.

35. The sole member of claim 34 wherein the dorsal surface has a convex shape above the angular displacement member for receiving at least a portion of the forefoot.

36. The sole member of claim 35 wherein the angular displacement member comprises a semi-deformable material and has relatively less compliancy and resiliency than that of the foot-strike member.

37. The sole member of claim 34 wherein the angular displacement member comprises an essentially non-deformable material.

38. The sole member of claim 34 wherein the angular displacement member comprises a semi-deformable material that has relatively less compliancy and resiliency than that of the foot-strike member.

39. The sole member of claim 38 wherein the angular displacement member comprises an essentially non-deformable material.