Upgraded sole for running footwear and related running footwear

Abstract

The present invention relates to a new upgraded sole having separate and specific areas designed to work in conjunction with each other, thus ensuring smooth transitions during stride with the introduction of a stiffening slab crossing the midsole in the median portion diagonally bringing it in direct contact with the tread sole in the frontal portion. It is thus possible to achieve a push-off phase with stable forefoot, from stance to strike, and a progressive displacement of the runner's center of gravity, transforming gravitational, inertial and reaction forces to the ground (as well as muscle tension forces), into propulsion, so as to optimize, at the same time, the energy efficiency of running by reducing shocks and relevant trauma while reducing, at the same time, the overall weight and thickness of the footwear.

Description

[0001] UPGRADED SOLE FOR RUNNING FOOTWEAR AND RELATED RUNNING FOOTWEAR

[0002] Technical Field

[0003] The present invention relates to an upgraded sole for footwear, preferably for running footwear. The invention also relates to running footwear using such an upgraded sole.

[0004] Background Art

[0005] Athletic shoes have undergone significant revolutions over the past three decades, particularly with regard to improvements in running shoes for both the professional and the casual user. In particular, improvements have largely focused on pronation support, shock absorption and increased energy efficiency.

[0006] Some well-known footwear has special structured soles to ensure better lateral stability in order to provide better shock absorption during the phase of first contact. Other shoes, on the other hand, focus on progressive contact systems to optimize the transition from stance to foot strike (roll). Still others are designed to increase propulsion during the push-off phase.

[0007] Kinesiological analysis studies made on runners have shown numerous correlations between biomechanics and running speed. In prolonged runs, such as the marathon, fatigued athletes tend to adopt unwanted and counterproductive gaits. It is very common to observe athletes striking the ground with their heel, generating high impacts and contact pressures that can put strain on the foot, ankle and knee joints, which are subject to damaging and unwanted movements. In more detail, during the phase of first contact with the heel, the foot is in supination and as contact continues it takes on a position of pronation thus allowing partial absorption of the impact forces. During the transition from the medial support to the push-off phase, the load transfers from the lateral side to the forefoot as the foot becomes a rigid lever. This continuous movement results in a transition from the lateral contact to the medial forefoot contact as the foot accelerates during the foot strike phase. Numerous attempts have been developed over the years trying to improve the energy efficiency of running in general. The use of footbed within footwear or slabs fitted into the midsoles is e.g. generally quite well known.

[0008] Patent US 2014 / 0059895 Al, for example, describes an anatomical footbed to be fitted into shoes in order to improve propulsion in walking, running and jumping activities.

[0009] Patent US 10,448,704 B2 describes a rigid slab fitted into the sole to decrease energy expenditure during dorsiflexion of the foot without, however, reducing the mechanical efficiency of the plantar flexors of the ankle when running.

[0010] Patent US 2004 / 0205983 Al describes the correlation between three sole portions during the contact, stance and strike phases and how the ratios between the shapes and materials of these portions are developed in order to more effectively transfer gravitational, inertial and reaction forces to the ground by promoting more efficient running, reducing shocks and relevant trauma in the foot.

[0011] Patent US 2012 / 0266500 Al describes an insert at the front of the sole to allow for greater flexion and extension of the foot when walking, thus giving a mechanical advantage across the metatarsal joint in order to generate an upward plantar force during foot strike so as to increase stride length without changing the walking pattern.

[0012] Patent US 11,109,639 B2 describes a slab formed by a dorsal layer made of soft woven fabric and a hard plantar layer formed by a reinforced composite material. The layer is configured to provide the user with good flexibility and range of foot motion without sacrificing the structural rigidity and / or stability of footwear.

[0013] Description of the Invention

[0014] By virtue of existing prior arts, the Applicant considered improving the known running footwear by making a new upgraded sole having separate and specific areas designed to work in conjunction with each other, thus ensuring smooth transitions during stride.

[0015] Thus, the Applicant found that by introducing a stiffening slab crossing the midsole in the median portion diagonally bringing it in direct contact with the tread sole in the frontal portion, it is possible to achieve a push-off phase with stable forefoot, from stance to strike, and a progressive displacement of the runner’s center of gravity, transforming gravitational, inertial and reaction forces to the ground (as well as muscle tension forces), into propulsion, so as to optimize, at the same time, the energy efficiency of running by reducing shocks and relevant trauma while reducing, at the same time, the overall weight and thickness of the footwear.

[0016] At least the aforementioned objects and benefits are achieved by an upgraded sole for running footwear in accordance with claim 1.

[0017] An additional object of the present invention is achieved by the running footwear in accordance with claim 10.

[0018] Brief Description of the Drawings

[0019] Further characteristics and advantages of the invention will be more evident from the description of some preferred, but not exclusive, embodiments of the sole according to the invention illustrated, by way of an indicative and not limiting example, in the attached tables of drawings in which:

[0020] - Figure 1 is an exploded view of the various layers composing a footwear and containing a stiffening slab in accordance with the invention;

[0021] - Figure 2 is a perspective view from above of the sole of the footwear in Figure 1;

[0022] - Figure 3 is a view from below of the sole in Figure 2;

[0023] - Figure 4 is a perspective view from above of the rear midsole sector according to the invention;

[0024] - Figure 5 is a view from above of the midsole sector in Figure 4;

[0025] - Figure 6 is a perspective view from below of the rear midsole sector in Figure 4;

[0026] - Figure 7 is a view from above of the front midsole sector according to the invention;

[0027] - Figure 8 is a perspective view from below of the front midsole sector in Figure 7;

[0028] - Figure 9 is a view from below of the front midsole sector in Figure 7; - Figure 10a is a view from above of the stiffening slab according to the invention;

[0029] - Figure 10b is a side cross-sectional view of the midsole containing the stiffening slab of the invention;

[0030] - Figure 10c is a side cross-sectional view of the stiffening slab according to a first embodiment;

[0031] - Figure lOd is a side cross-sectional view of the stiffening slab according to a second embodiment;

[0032] - Figures 11 and 12 are perspective views from above and from below of the slab in Figure 10a;

[0033] - Figure 13 is an exploded view of the various layers composing a shoe containing an additional slab in accordance with the invention;

[0034] - Figure 14 is a view from above of the additional slab in Figure 13,

[0035] - Figures 15a- 15d are views from above of special drawings of the adhesion paths or points 9a of the additional slab;

[0036] - Figures 16a- 16c are side cross-sectional views of the behaviors of the stiffening slab and of the additional slab in the different compression / traction configurations of the footwear.

[0037] Embodiments of the Invention

[0038] With reference to the figures mentioned above, reference numeral 1 globally denotes a running footwear comprising an upper 2 and an upgraded sole 3 extended overall along a longitudinal direction X-X. The sole 3 in turn comprises a tread 5 and a midsole 4, the latter being placed altogether between the upper 2 and the tread 5. A footbed (not shown) may also be placed between the upper 2 and the midsole 4. The aforementioned elements are intended to be glued together according to techniques known in themselves and not shown in detail in the remainder of this description as they are common to a technician in the branch.

[0039] As can be observed, the midsole 4 comprises a rear midsole sector 6 and a front midsole sector 7. Specifically, the rear midsole sector 6 substantially represents the backfoot support area of a user while the front midsole sector 7 substantially corresponds to the forefoot support area of the user. The midsole 4 is substantially divided into two parts by means of an imaginary cutting plane T (Figure 2) that identifies: the rear midsole sector 6 and the front midsole sector 7 which may be aligned and joined together, as will be described in detail later in this disclosure. This configuration allows the reduction of the overall thickness, with a reduction in the footwear weight.

[0040] Preferably, the normal of the cutting plane T is directed transversely to the direction X-X by an angle approximately of between 15° and 45°. Preferably, the cutting plane T has a curvilinear profile with concavity facing the front midsole sector 7. Specifically, the cutting plane T has a circular profile with a predefined radius of curvature. It cannot, however, be ruled out that the plane T may have different profile and orientations such as, e.g., sinusoidal shape, irregular shape or with concavity facing the rear midsole sector depending on the specific design requirements and the characteristics required for the midsole.

[0041] In accordance with one embodiment, the rear midsole sector 6 is made at least partly of compression-molded ethylene vinyl acetate for its cushioning properties while the front midsole sector 7 is made at least partly of ethylene vinyl acetate injected with supercritical nitrogen gas to achieve low compression values and high rebound abilities.

[0042] As shown in the examples in Figures 3, 4, and 5, the rear midsole sector 6 extends between a rear terminal end 6b and a front terminal end 6a facing the front of the footwear 1. The front midsole sector 7 extends between a front terminal end 7a and a rear terminal end 7b. The rear terminal end 7b substantially corresponds to the middle part of the footwear 1 and is intended to face the front terminal end 6a of the rear midsole sector 6.

[0043] The rear midsole sector 6 has an upper central depression 6c bounded by the sidewalls 6d, 6e and a plurality of lightening cavities 6f, 6g. In detail, the cavity 6f is a through lightening cavity extended vertically from the lower surface of the rear midsole sector 6 and positioned close to the front terminal end 6a, while the cavity 6g is a lightening cavity close to the rear terminal end 6b formed into the upper central depression 6c. As visible in Figure 5, the lightening cavity 6f is preferably elliptical in shape with a depth of between 4 mm and 8 mm and an overall orientation rotated with respect to the direction X-X by an angle A of between 30° and 45°. Conveniently, the portion of surface closely adjacent to the cavity 6f is the one intended to be directly glued to the upper 2.

[0044] As visible in Figure 4, the joining of the rear midsole sector 6 to the front midsole sector 7 is done by bonding at the two adhesion areas 6h, 6i (indicated by dashed lines) provided in the upper side of the rear midsole sector 6 at the sidewalls 6d, 6e, respectively. The two adhesion areas 6h, 6i extend for stretches of predetermined length from the front terminal end 6a preferably to about half the length of the rear midsole sector 6.

[0045] With reference to the Figure 4, the upper central depression 6c terminates towards the middle of the footwear 1 with a ramp profile having overall downward pattern for a stretch of predetermined length. Specifically, the upper central depression 6c has an initial stretch 6c’ with a substantially straight pattern, a final stretch 6c’” directed by an angle, with respect to the direction X-X, preferably of between 15° and 45° and a connecting stretch 6c”, between the initial stretch 6c’ and the final stretch 6c’”, curved downward.

[0046] As visible in Figures 7, 8 and 9, the front midsole sector 7 extends longitudinally between the front terminal end 7a and the rear terminal end 7b and also has an upper central depression 7c (bounded by the sidewalls 7d, 7e) where a plurality of lightening cavities 7f are made, preferably elliptical in shape, and distributed so as not to interfere with the most heavily loaded areas of the footbed and adapted to promote the deformation of the rear midsole sector 6 in the contact with the ground when running.

[0047] The joining of the front midsole sector 7 to the rear midsole sector 6 is done by axial bonding of the two adhesion areas 7g, 7h (indicated by dashed lines) provided in the lower side of the front midsole sector 7 to the two respective adhesion areas 6h, 6i. The adhesion areas 7g, 7h are placed at the sidewalls 7d, 7e, respectively, and extend for stretches of predetermined length starting from the rear terminal end 7b, preferably, to about half the length of the front midsole sector 7.

[0048] An additional “U-shaped” adhesion area 71 (indicated in Figure 9 by the dots) follows the peripheral profile of the front midsole sector 7 and serves as a bonding area for the tread 5. In one embodiment, the additional adhesion area 71 has a median extension 7i facing the center of the front midsole sector 7.

[0049] As shown, in the lower portion of the front midsole sector 7 there is a lower central depression 7m bounded by the sidewalls 7d, 7e and by the additional adhesion area 71 which, as will be seen later in this description, is intended to receive a stiffening slab 8 by shape coupling.

[0050] With reference to Figure 9, the lower central depression 7m terminates towards the middle of the footwear 1 with a curved pattern having an overall upward pattern for a stretch of predetermined length. In particular, the lower central depression 7m has an initial stretch 7m’ with a substantially curvilinear pattern with concavity facing upward and a final stretch 7m” with a substantially straight pattern directed by an angle, with respect to the direction X-X, preferably of between 15° and 45°.

[0051] As visible in Figures 1 and 3, the tread 5 is preferably made of three pieces, one frontal piece 5a and two back pieces 5b and 5c intended to be glued to the front midsole sector 7 and to the rear midsole sector 6, respectively. In detail, the tread frontal piece 5a has two extensions 5a’, 5a” extending at the front terminal end 6a of the rear midsole sector 6 and glued thereto to increase the overall stability between the midsole sectors 6, 7.

[0052] Conveniently, the tread frontal piece 5 a is glued to the front midsole sector 7 at the additional adhesion area 71, while the extensions 5a’, 5a” are glued to the rear midsole sector 6 at the respective circular adhesion areas 61 bounded by the dashes shown in Figure 6. The two back pieces 5b and 5c of the tread 5 are glued to the rear midsole sector 6 at the adhesion area 6m (bounded by the hatching in Figure 6), the latter being partly formed around the lightening cavity 6f.

[0053] According to one version, the tread frontal piece 5 a may have reinforcement areas 5d intended to increase the stiffness in the bonding areas of the tread 5. The lower surface of the tread 5 is preferably grooved with transverse cut lines to improve traction on hard ground (e.g., road asphalt) characterized by frequent bumps and potholes. Preferably, the design of the tread frontal piece 5a has “V”- or “U”-shaped cut lines with concavity facing the middle part of the footwear 1. Similarly, the design of the two back pieces 5b and 5c also has “V”- or “U”- shaped cut lines with concavity facing the middle part of the footwear 1. It cannot, however, be ruled out that the shape and direction of the cut lines may have different geometries and orientations, such as e.g. circular, elliptical or irregular shapes, depending on the specific design requirements and the required tread characteristics.

[0054] In accordance with one embodiment, the tread 5 is made at least partly of thermoplastic material, such as e.g., acrylonitrile butadiene styrene-based rubber. Advantageously, as anticipated above, the sole 3 comprises a stiffening slab 8 configured to reduce energy loss at the metatarsophalangeal joint while improving foot roll during running. Such a slab thus avoids high energy expenditure during foot dorsiflexion without reducing the mechanical efficiency of the ankle’s plantar flexors during running.

[0055] As shown in Figures 1 and 10a- lOd, the slab 8 extends overall along X-X for a length slightly less than the length of the midsole 4. In the slab 8, there are a front portion 8a, a rear portion 8c and an intermediate connecting portion 8b between the front portion 8a and the rear portion 8c, the latter being intended to be joined by shape coupling to the upper central depression 6c of the front midsole sector 7 and to the lower central depression 7m of the rear midsole sector 6 respectively, and glued thereto. Advantageously, the rear portion 8c of the slab 8 is substantially arranged on top of the rear midsole sector 6, the front portion 8a of the slab 8 is arranged at the bottom of the front midsole sector 7, and the intermediate portion 8b of the slab 8 passes through the midsole 4 at the terminal ends 6a, 7b of the rear midsole sector 6 and of the front midsole sector 7.

[0056] With reference to the examples in Figures 11 and 12, in more detail, in the front portion 8a of the slab 8 there are two opposite surfaces 8a’ and 8a”, upper and lower, respectively; in the intermediate portion 8b there are two opposite surfaces 8b’ and 8b”, upper and lower, respectively; and in the rear portion 8c there are two opposite surfaces 8c’ and 8c”, upper and lower, respectively.

[0057] Specifically, with reference to the front portion 8a of the slab 8 intended to be glued to the front midsole sector 7:

[0058] - the upper surface 8a’ is glued to the lower central depression 7m at the initial stretch 7m’, and

[0059] - the lower surface 8a” is glued to the tread 5, particularly to the frontal piece 5a.

[0060] With reference to the intermediate portion 8b of the slab 8 intended to be glued to both the front midsole sector 7 and the rear midsole sector 6:

[0061] - the upper surface 8b’ is glued to the lower central depression 7m of the front midsole sector 7 at the final stretch 7m”,

[0062] - the lower surface 8b” is glued to the upper central depression 6c of the rear midsole sector 6 at the final stretch 6c’”.

[0063] With reference to the rear portion 8c of the slab 8 intended to be glued to the rear midsole sector 6:

[0064] - the upper surface 8c’ is glued to the footwear 1,

[0065] - the lower surface 8c” is glued to the upper central depression 6c at the initial stretch 6c’ and the connecting stretch 6c”.

[0066] In some examples, the rear portion 8c of the slab 8 extends from the lightening cavity 6f. In other examples, the rear portion 8c of the slab 8 extends around the lightening cavity 6f.

[0067] According to one embodiment, the slab 8 has a substantially uniform stiffness over the entire surface area of the slab 8. According to another embodiment, the slab 8 may be formed by at least two or more layers glued together to impart greater stiffness.

[0068] Preferably, the slab 8 is made of one or more materials selected from the group comprising: carbon fibers, aramid fibers, boron fibers, glass fibers, polymer fibers.

[0069] Preferably, the slab 8 has a substantially uniform thickness between about 0.6 mm and about 3.0 mm. It cannot, however, be ruled out that the thickness of the slab 8 is not uniform, e.g., the slab 8 could have greater thickness in the intermediate portion 8b to better adhere to the midfoot area.

[0070] In accordance with one embodiment, the front portion 8a of the slab 8 may have a central channel 8d extended longitudinally inward from the slab 8 and adapted to receive, by shape coupling, the median extension 7i of the additional adhesion area 71. The central channel 8d substantially identifies a cut in the front portion 8a that divides it into two sides: the right side that substantially corresponds to the big toe support area and the left side for the remaining toes.

[0071] As shown in the example in Figure 10c, the rear portion 8 c of the slab 8 has an overall straight pattern along the longitudinal direction X-X for a stretch of predetermined length, the front portion 8a of the slab 8 has an overall curvilinear pattern with radius of curvature R having a length approximately twice the length of the rear portion 8c and the intermediate portion 8b is directed by an angle a of between 15° and 45° with respect to the longitudinal direction X-X.

[0072] According to the embodiment in Figure lOd, the front portion 8a of the slab 8 has a curvilinear pattern with multiple radii of curvature. In the case illustrated, the front portion 8a terminates, for example, with an upward step bend. It cannot, however, be ruled out that the pattern of the front portion 8a may comprise different designs depending on the construction or stiffness requirements of the footwear 1.

[0073] In accordance with the embodiment shown in Figures 13 and 14, the footwear comprises an additional slab 9 with high tensile strength intended to be glued on top of the stiffening slab 8. Conveniently, the additional slab 9 has low compressive strength. The additional slab 9 has longitudinal pattern along X-X and transverse pattern substantially corresponding to the pattern of the stiffening slab 8. Preferably, the additional slab 9 has a substantially “S” shape to follow the pattern of the foot from the heel towards the big toe capable of making anisotropic properties by adding flexural stiffness only upon load transfer from the lateralposterior portion of the foot to the ball of the foot giving good stability of the sole 3 on uneven ground. Preferably, the additional slab 9 has a substantially uniform thickness of between about 0.2 mm and about 0.5 mm. It cannot, however, be ruled out that the thickness of the slab 9 may not be uniform, e.g., the slab 9 might have greater thickness in its median portion.

[0074] Conveniently, the additional slab 9 has a mechanical strength value (of elasticity or yield strength) substantially corresponding to the mechanical strength value of the stiffening slab 8. Preferably, the additional slab 9 has a lower value of mechanical strength (of elasticity or yield strength) than the value of mechanical strength of the stiffening slab 8.

[0075] Preferably, the additional slab 9 is made of one or more materials selected from the group comprising: carbon fibers, aramid fibers, boron fibers, glass fibers and polymer fibers. These fibers may change their orientation when the slab 9 undergoes compression, e.g. due to stride. Thus, the slab 9 may have a higher strength value in one direction than in another direction, or vice versa. For example, as shown in the example in Figs. 16b and 16c, the slab 9 of the invention shows lower strength if bent upward (Fig. 16c), while it shows higher strength if bent downward (Fig. 16b).

[0076] According to one version, the additional slab 9 may be impregnated with polyurethane aqueous solutions or silicone polyether copolymers in order to maintain high flexibility, promote bonding thereof and possibly prevent the side surfaces from fraying. For this purpose, the non-use of epoxy resins is suggested to maintain maximum flexibility.

[0077] According to one embodiment, the additional slab 9 is configured to be glued to the stiffening slab 8 at predetermined adhesion paths or points 9a (Figure 16a). Each adhesion path 9a is separated by a corresponding non-adhesion path or points 9b in order to promote the bending and detachment of certain zones of the additional slab 9 from the stiffening slab 8, e.g., when the footwear undergoes bending along the direction of dorsal bending of the toes of the metatarsophalangeal joints (Figure 16b). On the other hand, the non-adhesion portions or points 9b are loaded in tension when the footwear is stressed to bend in the opposite direction to that described above, maintaining high stiffness (Figure 16c).

[0078] Advantageously, the adhesion paths or points 9a may have predetermined designs / paths, such as those shown in Figures 14, 15a- 15d. Conveniently, the adhesion paths 9a are made through the use of computerized machines or rollers with preformed paths.

[0079] With reference to the example shown in Figure 10b, a cross-sectional view of the midsole 4 is shown wherein the front portion 8a of the stiffening slab 8 is positioned below the front midsole sector 7, the rear portion 8c is positioned above the rear midsole sector 6, and the intermediate portion 8b is positioned at the cutting plane T between the two midsole sectors 6, 7.

[0080] Again with reference to the example shown in Figure 10b, the front midsole sector 7 has vertically extended through lightening cavities 7n, 7o. Conveniently, the intermediate portion 8b of the slab 8 crosses the through lightening cavities 7n, 7o resulting visible from below at the most central cavity 7o.

[0081] It has in practice been ascertained that the described invention achieves the intended objects, and in particular, the fact is emphasized that the upgraded sole enables high comfort during use and transfers gravitational, inertial and ground reaction forces as effectively as possible so as to enable more efficient running with less energy consumption by minimizing shocks and trauma.

[0082] The type of structural combinations of the upgraded sole as well as of the footwear incorporating it are potentially infinite and obviously a technician in the field, in order to meet contingent and specific needs, will be able to make numerous modifications and variations to the embodiments described above, all of which, moreover, are contained within the scope of protection of the invention as defined by the following claims.

Claims

CLAIMS1) Upgraded sole (3) for running footwear placed between the upper (2) and the tread (5) of a footwear (1), comprising: a midsole (4) extended overall along a longitudinal direction (X-X) and having: a rear midsole sector (6) for the support of a user’s rearfoot, a front midsole sector (7) for the support of the user’s forefoot, wherein the front terminal end (7a) of the front midsole sector (7) faces the rear terminal end (6b) of the rear midsole sector (6), a stiffening slab (8) wherein the following items are identified a front portion (8a), a rear portion (8c), and an intermediate connecting portion (8b) between the front portion (8a) and the rear portion (8c), characterized by the fact that the rear portion (8c) of the stiffening slab (8) is arranged above the rear midsole sector (6), the front portion (8a) of the stiffening slab (8) is arranged below the front midsole sector (7), and the intermediate portion (8b) of the stiffening slab (8) passes through the midsole (4) where the front terminal end (7a) of the front midsole sector (7) and the rear terminal end (6b) of the rear midsole sector (6) are located.2) Upgraded sole (3) according to claim 1 or 2, wherein the rear portion (8c) of the slab (8) has an overall straight pattern along the longitudinal direction (X- X) for a predetermined length.3) Upgraded sole (3) according to one or more of the preceding claims, wherein the front portion (8a) of the slab (8) has an overall curvilinear pattern with radius of curvature (R) having a length approximately twice the length of the rear portion (8c).4) Upgraded sole (3) according to one or more of the preceding claims, wherein the intermediate portion (8b) of the stiffening slab (8) is directed withrespect to the longitudinal direction (X-X) by an angle (X) approximately of between 15° and 45°.5) Upgraded sole (3) according to one or more of the preceding claims, wherein said front midsole sector (6) has an upper central depression (6c) and the rear midsole sector (7) has a lower central depression (7m), and wherein said front portion (8a) and said rear portion (8c) of the slab (8) are intended to be joined by shape coupling to the upper central depression (6c) of the front midsole sector (6) and to the lower central depression (7m) of the rear midsole sector (7), respectively6) Upgraded sole (3) according to one or more of the preceding claims, wherein the midsole (4) is divided into two parts by means of a cutting plane (T) identifying the rear midsole sector (6) and the front midsole sector (7), the normal of said cutting plane (T) being directed transversely with respect to the direction (X-X) by an angle approximately of between 15° and 45°.7) Upgraded sole (3) according to one or more of the preceding claims, wherein said stiffening slab (8) is made of one or more materials selected from the group comprising: carbon fibers, aramid fibers, boron fibers, glass fibers, polymer fibers.8) Upgraded sole (3) according to one or more of the preceding claims, comprising an additional slab (9) glued on top of the stiffening slab (8) and having a substantially “S” shape to follow the pattern of the foot from the heel towards the big toe.9) Upgraded sole (3) according to the preceding claim, wherein said additional slab (9) is made of one or more materials selected from the group comprising: carbon fibers, aramid fibers, boron fibers, glass fibers, polymer fibers.10) Running footwear (1) comprising an upper (2) associated with a sole (3) according to one or more of the preceding claims.

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