Shoes

Abstract

To provide shoes that ensure both foot stability and ankle flexibility while walking and bending and stretching the knees while supporting a weight load with both feet. [Solution] A lifting shoe (1) comprises a sole (10) and an upper (20). A sole region dividing line (DL) is set on the sole (10) closer to the heel than the MP joint (α), dividing the entire sole region (SA) into a forefoot region (FA) and a rearfoot region (BA). The sole (10) comprises an outsole (11) and a midsole (12). The outsole (11) has an outsole forefoot portion (110) in the forefoot region (FA) that includes the region corresponding to the MP joint (α). When a reference sole shape (SS) is defined as a circumferential foot shape drawn along the outline of a wearer's foot (F), the outsole forefoot portion (110) is set to have a sole shape with an enlarged sole portion (115) whose sole area expands outward from the periphery of the reference sole shape (SS).

Description

[Technical Field]

[0001] The present disclosure relates to shoes. [Background technology]

[0002] Conventional lifting shoes are known to use high-hardness rubber for the outsole material, have a carbon plate in the toe area of ​​the outsole, and have a sole and upper that narrows toward the toes to maximize the force pushing against the floor and floor reaction force when lifting heavy weights, and to prevent the foot from twisting (torsion) inside the shoe and causing it to become unsteady (hereinafter referred to as "Conventional Example 1").

[0003] In weightlifting competitions and training, lifters perform lifting maneuvers such as the snatch, clean, and jerk, jumping while attempting to lift a heavy weight and then landing with their legs spread apart horizontally or vertically. Conventional lifting shoes, on the other hand, use TPU material for the heel to withstand the impact of landing. Furthermore, conventional lifting shoes are designed with a sole and upper in the toe area to ensure sufficient space for the foot, allowing the foot joints, such as the forefoot, to bend easily in response to the landing motion. Patent Document 1 discloses a type of shoe that uses a soft material for the midsole in the forefoot area (hereinafter referred to as "Prior Art 2"). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2024 / 0215679 Summary of the Invention [Problem to be solved by the invention]

[0005] The squat, a lifting technique used in powerlifting competitions and training, involves lifting a (very) heavy barbell from a rack onto the back and shoulders (holding it behind the back), taking several backsteps, deeply bending the knees, and fully straightening the bent knees to stand up. This series of movements is performed while leaning the upper body forward within a specified time frame. Therefore, powerlifters who perform squats as a competitive event and those who perform them in training do not jump when lifting heavy weights, unlike lifting techniques such as snatches, cleans, and jerks. For this reason, squatters desire lifting shoes that ensure both foot stability and ankle flexibility, rather than simply dealing with the impact and movement of landing. Here, "ensuring foot stability" refers to preventing the feet from wobbling in the shoes while walking, including backsteps, and during knee flexion and extension movements, thereby preventing the feet from wobbling while supporting the weight load. Furthermore, "ensuring flexibility of ankle joint bending" means ensuring the mobility of the forefoot, i.e., the ease of bending the foot from the MP joint, so that the center of gravity can be optimized during walking, including backstepping, and the force pushing against the floor and the floor reaction force can be maximized during knee bending and extension movements.

[0006] In contrast, the lifting shoes of Conventional Example 1 use a high-hardness rubber material for the outsole and have a carbon plate in the toe area of ​​the outsole, which suppresses wobbling within the shoe and ensures foot stability. However, the shoe structure of Conventional Example 1 compresses the toes to prevent the foot from wobbling within the shoe, which causes the transverse arch, which expands laterally at the MP joint, to collapse. As a result, the lifting shoes of Conventional Example 1 have the problem that the foot does not bend from the MP joint position during walking while supporting a weight load with both feet and during knee flexion and extension, resulting in a lack of ankle joint bending adaptability.

[0007] Furthermore, the lifting shoes of Conventional Example 2 ensure flexibility of the ankle joint. However, because the shoe structure of Conventional Example 2 uses a soft material for the midsole in the forefoot, the forefoot sinks into the shoe in a twisted state to a certain extent toward the width of the foot, i.e., toward the inside or outside of the foot. As a result, the lifting shoes of Conventional Example 2 have the problem that the foot wobbles in the shoe and lacks foot stability while walking and bending and stretching the knees while supporting a weight load with both feet.

[0008] The present disclosure has been made with a focus on the above-mentioned problems, and aims to provide shoes that achieve both foot stability and ankle flexibility while walking and bending and extending the knees while supporting a weight load with both feet. [Means for solving the problem]

[0009] The shoe of the present disclosure comprises a sole and an upper fixed to the sole and covering the upper portion of the wearer's foot. The sole has a sole region dividing line set at a position closer to the heel than the MP joint, which bends between the metatarsal and phalanges at the base of the toes, and the sole region dividing line divides the entire sole region into a forefoot region on the toe side and a rearfoot region on the heel side. The sole has an outsole with a contact surface that comes into contact with the floor or ground, and a midsole fixed on top of the outsole. The outsole has an outsole forefoot section in the forefoot region that includes the region corresponding to the MP joint. When a circumferential foot shape drawn along the outline of the wearer's foot is used as a reference sole shape, the outsole forefoot section is set to have an enlarged sole section whose sole area expands outward from the periphery of the reference sole shape. The outsole is provided over the entire sole area, which includes the forefoot area and the rearfoot area. The midsole is provided in the rearfoot area. The forefoot area of ​​the outsole is set to have a bending rigidity that allows plantar flexion and dorsiflexion of the foot from the MP joint. The material of the outsole is a high-hardness rubber material. The forefoot area of ​​the outsole is provided with a reinforcing plate made of a material harder than the high-hardness rubber material in the toe area, which includes the area corresponding to the MP joint. [Effects of the Invention]

[0010] The shoes of the present disclosure can ensure both foot stability and ankle joint bending flexibility while walking and bending and straightening the knees while supporting a weight load on both feet. In addition, the reinforcing plate serves the functions of adjusting the bending rigidity of the forefoot region of the outsole, suppressing sinking when the foot is twisted, and improving the force pushing against the floor and the floor reaction force from the floor. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing the appearance of a pair of lifting shoes according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing a sole surface of a lifting shoe. [Figure 3] FIG. 2 is a bottom view showing the bottom surface of the sole of the lifting shoe. [Figure 4] FIG. 2 is a side view showing the side surface of the sole provided on the lifting shoe. [Figure 5] 3 is a diagram showing the planar structure of the sole cover sewn and fixed to the upper and the cross-sectional structure of the sole taken along line AA in FIG. 2. FIG. [Figure 6] 3A is a diagram showing the sole back structure taken along line BB in FIG. 2, FIG. 3B is a diagram showing the sole cross-sectional structure taken along line CC in FIG. 2, and FIG. 3C is a diagram showing the sole cross-sectional structure taken along line DD in FIG. 2. [Figure 7] FIG. 1 is an explanatory diagram showing the skeletal structure of the foot having MP joints. [Figure 8] FIG. 2 is a plan view showing a forefoot portion of the outsole. [Figure 9] 9 is a cross-sectional view showing the cross-sectional structure of the forefoot part of the outsole taken along line EE in FIG. 8. [Figure 10] 10 is an explanatory diagram showing plantar flexion and dorsiflexion of the foot. FIG. [Figure 11] FIG. 1 is an explanatory diagram of a squat competition that explains the method of squat competition. [Figure 12] FIG. 1 is an explanatory diagram showing the transverse arch, lateral longitudinal arch, and medial longitudinal arch. [Figure 13] 10 is a diagram illustrating the foot bending action on the toe side in a shoe of a comparative example. FIG. [Figure 14] FIG. 2 is a perspective view showing the toe break position in the lifting shoe of the first embodiment, viewed from diagonally above the front side. [Figure 15] FIG. 10 is an explanatory diagram of the foot bending action from the toe break position in the lifting shoe of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The shoe of the present disclosure will be described with reference to the accompanying drawings showing a lifting shoe (an example of a shoe) according to a first embodiment of the present disclosure. In the accompanying drawings, the X-axis represents the longitudinal axis that corresponds to the length of the foot, and the Y-axis represents the transverse axis that is perpendicular to the X-axis and corresponds to the width of the foot. In the accompanying drawings, the shoe center line is designated CL0, the toe center line is designated CL1, and the heel center line is designated CL2. The shoe center line CL0 is a line connecting the first toe position P0 and the heel position P2. The toe center line CL1 is a line drawn from the second toe position P1, which is located inside the first toe position P0, to divide the forefoot. The heel center line CL2 is a line drawn from the heel position P2 to divide the rearfoot. In the description of the first embodiment, FIG. 1 will focus on lifting shoes for both left and right feet, and FIGS. 2 to 15 will focus on a lifting shoe for the right foot. (Embodiment 1)

[0013] [Overall structure of lifting shoes (Fig. 1 to 7)] As shown in FIGS. 1 to 6, the lifting shoe 1 comprises a sole 10, an upper 20 fixed to the sole 10 and covering the upper part of the wearer's foot excluding the sole 10, and a sole cover 30.

[0014] As shown in Figure 7, the skeleton of foot F has the following tarsal bones: calcaneus B1, talus B2, navicular B3, cuboid B4, and three cuneiform bones B5, B6, and B7. The skeleton of foot F has the following metatarsal bones: B8, B9, B10, B11, and B12. The skeleton of foot F has the following phalanges: five proximal phalanges B13, B14, B15, B16, and B17, four middle phalanges B18, B19, B20, and B21, and five distal phalanges B22, B23, B24, B25, and B26. The MP joint α is a joint that connects the five metatarsals B8, B9, B10, B11, and B12 with the five proximal phalanges B13, B14, B15, B16, and B17.

[0015] As shown in FIG. 2, the sole 10 has a sole region division line DL set at a position closer to the heel than the MP joint α, which bends between the metatarsal and phalanges at the base of the toes. As shown in FIG. 2, the sole 10 divides the entire sole region SA into a forefoot region FA on the toe side and a rearfoot region BA on the heel side by the sole region division line DL set in the Y-axis direction. For example, when the total length in the X-axis direction is 100%, the sole region division line DL is set at a position approximately 40% from the front tip of the outsole, where the MP joint α is included in the forefoot region FA. The sole 10 has an outsole 11 having a contact surface 111 with the floor G, and a midsole 12 fixed on top of the outsole 11. The sole 10 has both the outsole 11 and the midsole 12 in the rearfoot region BA, and only the outsole 11 in the forefoot region FA.

[0016] The outsole 11 is a sole component used in the portion that comes into contact with the floor G, and is provided over the entire sole area SA, which includes the forefoot area FA and the rearfoot area BA. The outsole 11 is made of a hard rubber material known as high-hardness rubber. The outsole 11 has a contact surface 111, an outsole joining surface 112, an outsole surface 113, and an outsole peripheral wall portion 114. The outsole 11 has an inner surface shape that encloses the toe portion of the foot F in the forefoot area FA, leaving a space between them.

[0017] As shown in FIG. 3, the contact surface 111 has an anti-slip structure for contacting the floor surface G and is a fully flat surface with a flat surface. The sole shape of the contact surface 111 is the same as the enlarged sole shape of the outsole 11, which will be described later. Therefore, the contact area of ​​the contact surface 111 with the floor surface G is enlarged compared to the contact area when the outsole has a standard sole shape. The anti-slip structure has wavy recesses 111a and elliptical recesses 111b. Multiple wavy recesses 111a are formed at predetermined intervals in the X-axis direction, and each of the multiple recesses extends in the Y-axis direction. Multiple elliptical recesses 111b are formed side by side in the Y-axis direction between multiple wavy recesses 111a adjacent in the X-axis direction. The outsole bonding surface 112 is adhesively bonded to the midsole 12 in the rearfoot region BA and integrated therewith. The outsole surface 113 has an outsole recess 113a formed by a depression in the center, as shown in FIG. 2. 4, the outsole peripheral wall 114 rises along the toe area from the area overlapping with the midsole 12. The outsole peripheral wall 114 rises higher in the area overlapping with the midsole 12 and in the outsole front area, and these areas are connected by a smooth concave curve.

[0018] The midsole 12 is a sole component that ensures foot-supporting rigidity in the rearfoot region BA, and is provided only in the rearfoot region BA as shown in Figures 2 and 4 to 6. The midsole 12 is made of hard TPU, which has strength similar to that of hard plastic. TPU stands for "Thermoplastic Polyurethane," and is a thermoplastic polyurethane elastomer. The midsole 12 has a midsole surface 121, a midsole bonding surface 122, a midsole peripheral wall portion 123, and a midsole reinforcement portion 124. The midsole 12 has an inner surface that conforms to the shape of the heel of the foot F in the rearfoot region BA and encases it.

[0019] As shown in FIG. 2, the midsole surface 121 has a plurality of midsole recesses 121a in a bottom surface region that coincides with the sole of the foot in the rearfoot region BA. The midsole recesses 121a form a partial support surface that is continuous with the midsole surface 121. The midsole bonding surface 122 is adhesively bonded to the outsole 11 in the rearfoot region BA and is integrated therewith. As shown in FIGS. 4 and 6, the midsole peripheral wall 123 rises along the outer periphery of the midsole surface 121. The height of the midsole peripheral wall 123 is highest at the heel of the foot F and gradually decreases from the heel toward the forefoot region FA. The midsole reinforcement 124 is formed by a plurality of triangular protrusions that are continuous along the entire outer periphery of the midsole peripheral wall 123, as shown in FIGS. 4 and 6(a).

[0020] As shown in FIG. 1, the upper 20 comprises an upper main body 21, an inner lining 22, a heel lining 23, a tongue 24, shoelaces 25, a first strap 26, and a second strap 27. The upper main body 21 is made of synthetic leather, which is easy to process and to make strong. The upper main body 21 has multiple ventilation holes 21a in the toe area to ensure breathability. The upper 20 has a double-strap structure with the first strap 26 and the second strap 27 secured with hook-and-loop tape, allowing the wearer to easily adjust the tightness of the fit.

[0021] As shown in FIG. 5 , the sole cover 30 is fixed integrally to the upper 20 by sewing along the lower edge of the opening of the upper 20. The sole cover 30 is formed in a flat shape and has a foot-shaped form that matches the sole surface shape of the sole 10. The sole cover 30 is made of a soft TPU cloth material that is more flexible than the hard TPU material of the midsole 12 and has a supple elasticity similar to rubber. The sole cover 30 is fixed integrally to the upper 20 by sewing, and its cover bottom surface is adhesively bonded to the sole surface of the sole 10. That is, the lifting shoe 1 is manufactured through a sole assembling process, an upper assembling process, and a shoe assembling process. In the sole assembling process, the hard TPU midsole 12 is fixed onto the hard rubber outsole 11 with an adhesive. In the upper assembling process, the soft TPU sole cover 30 is pre-sewn to the upper 20. In the shoe assembly process, an adhesive is interposed between the bottom surface of the sole cover 30 sewn to the upper 20 and the surface of the sole 10, and they are bonded and fixed by pressure bonding using a press machine.

[0022] [Detailed structure of the forefoot of the outsole (Fig. 2, Fig. 8 to Fig. 10)] The outsole 11 has an outsole forefoot portion 110 in a forefoot region FA that includes an area corresponding to the MP joint α. The sole shape, bending rigidity, and dimensions of the outsole forefoot portion 110 are described below. The sole shape of the outsole forefoot portion 110 is set to have an expanded sole portion 115 whose sole area expands outward from the outer periphery of the reference sole shape SS. The reference sole shape SS is a circumferential foot shape drawn along the outline of the wearer's foot F. As shown by the hatching in Figures 2 and 8, the area of ​​the expanded sole portion 115 is determined to be sufficiently large, taking into account variations in the reference sole shape SS due to individual differences between wearers. In other words, the outsole forefoot portion 110 is shaped to form a forefoot accommodation space that ensures free movement of the forefoot around the entire periphery of the reference sole shape SS while absorbing variations due to individual differences between wearers.

[0023] The flexural rigidity of the outsole forefoot portion 110 is set to a rigidity that allows plantar flexion and dorsiflexion of the foot F from the MP joint α. Here, plantar flexion of the foot F refers to the movement of bending the portion from the MP joint α to the toe downward, as shown in FIG. 10. Dorsiflexion of the foot F refers to the movement of bending the portion from the MP joint α to the toe upward, as shown in FIG. 10. The sole configuration is such that the outsole 11 is located over the entire sole region SA, which includes the forefoot region FA and the rearfoot region BA, and the midsole 12 is located only in the rearfoot region BA. Therefore, the flexural rigidity of the outsole forefoot portion 110 is determined by the flexural rigidity set by the combination of the portion of the outsole 11 that extends forward from the end (sole region division line DL) of the rearfoot region BA that includes the midsole 12, and a reinforcing plate 117 (described later) provided in the toe portion.

[0024] The outsole forefoot portion 110 is provided with a reinforcing plate 117 made of a material harder than high-hardness rubber in the toe area including the region corresponding to the MP joint α. As shown in FIGS. 2 and 5, this reinforcing plate 117 is fitted and fixed into an outsole recess 113a formed in the outsole forefoot portion 110. The reinforcing plate 117 is made of, for example, a carbon plate made of carbon resin. The depth of the outsole recess 113a is equal to the thickness of the reinforcing plate 117. As shown in FIG. 8, when the region corresponding to the MP joint α is referred to as a boundary region, the reinforcing plate 117 has a first plate portion 117a located on the heel side of the boundary region, a second plate portion 117b located on the toe side of the boundary region, and a plate connecting portion 117c located in a position corresponding to the boundary region. The first plate portion 117a has a bifurcated shape extending from the position of the MP joint α toward both the diagonally outward and inward directions of the foot width to a position slightly beyond the sole region dividing line DL. The second plate portion 117b has a protruding shape extending from the position of the MP joint α toward the diagonally outward direction of the foot width. The vertical bending rigidity of the first plate portion 117a of the reinforcing plate 117 is set higher than that of the second plate portion 117b. The plate connecting portion 117c, which connects the first plate portion 117a and the second plate portion 117b at the outer portion of the foot width, is set to a constricted shape with a smooth concave curve. In other words, if the aim was only to increase rigidity, the plate shape of the reinforcing plate 117 would have an outer shape including the dashed line. However, by making this outer shape constricted by removing the hatched portion 118 in FIG. 8, bending from the position of the MP joint α is promoted.

[0025] As shown in FIGS. 9 and 10 , the expanded sole width dimension FW of the outsole forefoot portion 110 is set to the dimension obtained by adding the medial expanded width ΔWin and the lateral expanded width ΔWout to the reference sole width dimension SW of the reference sole shape SS. The medial expanded width ΔWin is the width expanded medially from the reference sole shape SS. The lateral expanded width ΔWout is the lateral expanded width expanded medially from the reference sole shape SS. The portion of the outsole forefoot portion 110 that is the sum of the medial expanded width ΔWin and the lateral expanded width ΔWout forms the expanded sole portion 115. The expanded sole portion 115 is set to a shape in which the medial expanded width ΔWin and the lateral expanded width ΔWout gradually expand from the sole region division line DL toward the region corresponding to the MP joint α. In other words, the expanded sole width dimension FW is set to be the widest dimension in the region corresponding to the MP joint α. Therefore, as shown in Figure 9, the cross-sectional structure of the region corresponding to the MP joint α is a structure in which an MP joint accommodating space is formed by the inner surface of the sole with the expanded sole width dimension FW in the forefoot region FA where the MP joint α is located and the inner surface of the upper 20. The MP joint accommodating space is a space around the foot F that ensures free movement of the MP joint α. The position where the sole width expansion begins in the sole 10 is the position corresponding to the arch of the foot F (the position indicated by the dashed line at the bottom of Figure 8), where the sole width dimension is narrowest. Therefore, the sole 10 has a common expanded sole portion that is common to the outsole 11 and midsole 12, in the range from the position corresponding to the arch to the sole region dividing line DL.

[0026] As shown in Fig. 8, a toe division line JL that divides the toe area is set at a position a predetermined distance inward from the second toe position P1 in the outsole forefoot portion 110. The portion formed by narrowing the sole width from the toe division line JL toward the toe is the toe sole portion 116. Here, the toe division line JL is set in a direction perpendicular to the toe center line CL1 that starts at the second toe position P1 of the sole 10, and at a position a predetermined distance (for example, approximately 45 mm) away from the second toe position P1, which is the front tip of the outsole, toward the heel.

[0027] The sole shape of the toe sole portion 116 has a sole width at the toe division line JL that is wider than the sole width at the toe division line JL in the reference sole shape SS. The sole shape of the toe sole portion 116 is set so that the reduction rate of the sole width from the toe division line JL toward the toes is lower than the reduction rate of the sole width in the reference sole shape SS. As shown in FIG. 8, the toe sole portion 116 has a sole shape that is determined to have sufficient width, taking into account variations in the reference sole shape SS due to individual differences between wearers. Therefore, the sole cross-sectional structure of the toe sole portion 116 is designed to form a toe-accommodating space that ensures free movement of the five toes while absorbing variations due to individual differences between wearers. The accommodation space for the foot F in the forefoot area FA is formed by the accommodation space for the MP joint and the accommodation space for the toes, and is considered to be a space equivalent to about 8E when converted into shoe size (JIS: Japanese Industrial Standards) based on the foot circumference, which represents the circumference from the base of the big toe to the base of the little toe.

[0028] Specific examples of the dimensions of the toe sole portion 116 are set as follows, where L0 is the foot dimension, L1 is the parting line dimension, and L2 is the toe width dimension. Foot dimension L0 is the length dimension of the foot F from the shoe center line CL0. Parting line dimension L1 is the dimension from the second toe position P1 to the toe parting line JL. Toe width dimension L2 is the effective length dimension of the toe parting line JL. L0:258.94mm, L1:45.05mm, L2:102.71mm L0:268.94mm, L1:45.03mm, L2:104.09mm L0:279.95mm, L1:45.00mm, L2:105.50mm L0:288.95mm, L1:45.01mm, L2:106.75mm In this way, specific examples of the dimensions of the toe sole portion 116 are such that, when the parting line dimension L1 is set to a substantially constant dimension (approximately 45 mm), the toe width dimension L2 is set to be longer as the foot dimension L0 becomes longer.

[0029] The upper 20 includes an upper main body 21 that covers the outsole forefoot portion 110, and a first strap 26 and a second strap 27 arranged in the foot width direction. Hereinafter, when the outsole forefoot portion 110 and the upper main body 21 bend from a position corresponding to the MP joint α, the bending position of the upper main body 21 is referred to as the "toe break position TP." Furthermore, the bending deformation region of the upper main body 21, including the toe break position TP, is referred to as the "toe break area TPA" (see FIGS. 14 and 15). The second strap 27, which is positioned closest to the toe, of the first strap 26 and the second strap 27 is positioned to avoid interference with the toe break area TPA, in other words, to not interfere with the toe break area TPA. Herein, "toe break" refers to bending of the sole 10 and upper 20 in the forefoot. The phrase "the second strap 27 does not interfere with the toe break area TPA" means that they do not interfere with each other in the vertical and foot width directions.

[0030] [Background technology for lifting shoes (Figure 11)] Powerlifting is a sport in which competitors compete to see who can lift the most weight in three events: squat, bench press, and deadlift. Squats are an event that primarily tests leg strength (standing ability), in which participants carry a barbell on their back and shoulders, squat to a specified depth, and then stand up. The following movements are performed: 1. Remove the barbell from the rack, hold it behind your back, and step back to lower yourself to a suitable position. 2. Maintain an upright position with your knees fully extended and wait for the referee's signal to "squat" (Figure 11(a)). 3. After receiving the signal, bend your knees and squat down until the top of your thighs at the hip joints is lower than the top of your knees (Figure 11(b) and (c)). 4. After standing up, straighten your knees, maintain an upright position, and wait for the referee's signal to "ruck" (Figure 11 (d), (e)). 5. After the signal, return the barbell to the rack. Since the squat involves holding the barbell behind the back, it is sometimes called the "back squat" in lifting competitions other than powerlifting and other sports.

[0031] The characteristics of the squat movement in powerlifting competitions are as follows: Feature 1: The competition rules require deep bending and stretching. Because deep bending and stretching movements are performed with (ultra) heavy weights, the upper body leans forward both when standing upright and during the movement (from bending down to standing up), as shown in Figure 11. Feature 2: There is no pushing off from the floor or ground or movement of the feet leaving the floor or ground. It is not necessary to completely lift the sole of your foot off the floor or ground during the backstep. Feature 3: Stability when standing is important. You are required to maintain an upright posture before and after bending and stretching.

[0032] Previous lifting shoes had the following problems: (1) A type in which a carbon plate is inserted in the toe area to increase sole rigidity and narrow the sole and upper toward the toes to prevent the foot from wobbling inside the shoe (conventional product 1). Conventional product 1 has a structure that compresses the toes, which causes the transverse arch formed at the MP joint of the foot to collapse. When the transverse arch collapses, the ankle joint lacks the ability to bend, preventing the arch function of the sole from being fully utilized during backsteps and bending and stretching movements. As a result, conventional product 1 makes it difficult to maintain balance during backsteps and bending and stretching movements, making it difficult to stabilize one's posture and lift heavy weights in squats. The transverse arch will be explained below in the section on the function of the arch of the sole of the foot. (2) A type in which the sole and upper in the toe area provide space for the foot, making it easy to bend the joints of the foot, but the midsole in the forefoot is made of a soft material without a carbon plate in the toe area (conventional product 2). Conventional Product 2 does not have a carbon plate in the toe area and the midsole in the forefoot is made of a soft material, so the forefoot sinks into the shoe with a certain degree of twisting in both the left and right directions. As a result, Conventional Product 2 causes the foot to wobble and lacks foot stability.

[0033] As described above, both Conventional Products 1 and 2 have a trade-off between preventing the foot from wobbling and making it easier to bend the foot joints. In other words, the conventional products only have two choices: prioritize foot stability (foot fixation force) by using a thick, hard material, or prioritize ease of bending the forefoot by using a thin or soft material.

[0034] [Promotes the arch function of the sole of the foot (Fig. 12 to 15)] First, as shown in Figure 12, the arches formed in the sole of the foot include the lateral longitudinal arch extending from the heel toward the ring toe, the medial longitudinal arch extending from the heel toward the big toe, and the transverse arch extending in the width direction of the foot along the MP joint. The main functions of the lateral longitudinal arch and medial longitudinal arch are spring action, cushioning action, and balancing action. The transverse arch also has the functions of shock absorption, which absorbs shocks applied to the foot from the sole, and foot stabilization, which is related to the rigidity (stability) of the foot and reduces wobble in the left and right direction.

[0035] If the function of the plantar arch can be maximized, it is possible to suppress foot wobble during backsteps and bending and straightening movements, and also maximize the pushing force and floor reaction force during bending and straightening movements, allowing for heavier weights to be lifted in squats without injury and in accordance with the rules. To maximize the function of the plantar arch, a wide toe box mechanism is desirable that maintains the transverse arch and the medial and lateral longitudinal arches while not compressing the movement of the foot joints and toes. Furthermore, to maximize the function of the plantar arch, a shoe that allows the toe break position to bend when pushing the foot out during a backstep away from the MP joint, where the foot's natural movement is possible, is desirable.

[0036] In contrast, the tapered toe shoe of Conventional Product 1, which incorporates a carbon plate in the toe area to increase sole rigidity, compresses the toes, reducing the height of the transverse arch, preventing the transverse arch from functioning properly and resulting in a lack of ankle joint flexibility to accommodate backstepping and knee flexion and extension. Furthermore, as shown in the comparative example (=Conventional Product 1) in Figure 13, Conventional Product 1 shoes bend the foot from the proximal phalanx rather than the MP joint during a backstep, resulting in the toe-break being positioned closer to the toes than the MP joint. In other words, with Conventional Product 1 shoes, the weight of the body and the barbell is placed on the front end, closer to the toes. This condition shifts the center of gravity forward during a backstep, requiring the use of calf muscles to avoid this, potentially leading to injury. Furthermore, because the toes are compressed and the toe-break is positioned closer to the toes, the center of gravity tends to remain in the forefoot even after completing a backstep and maintaining an upright posture in preparation for bending and extension. If the center of gravity remains in the forefoot, the calcaneus becomes unstable, making it difficult to maximize the function of the plantar arch when standing upright or squatting.

[0037] Conventional Product 2 shoes, which feature a wide toe box mechanism in the toe sole and upper, ensure flexibility in bending the ankle joint. However, Conventional Product 2 shoes do not include a carbon plate in the toe area and instead use a soft material in the forefoot midsole. Because a portion of the strap interferes with the bending deformation area of ​​the upper body, the forefoot sinks into the shoe with a certain degree of twisting in the width direction of the foot. Therefore, Conventional Product 2 shoes cause the foot to wobble in the shoe during backsteps and knee bending and extension movements, resulting in a lack of foot stability. Furthermore, because Conventional Product 2 shoes require backsteps and knee bending and extension movements with the forefoot in a depressed state, it is difficult for the plantar arch to fully function during these movements. As a result, Conventional Product 1 shoes with a tapered toe and Conventional Product 2 shoes with a wide toe box mechanism are unable to fully utilize the plantar arch function.

[0038] On the other hand, when lifting shoes are specifically designed for squats, whether in competition or for training or practice by athletes or non-athletes, there is no need to lift the entire sole of the foot from the floor or ground, so the shoes do not need to be durable enough to withstand landing impacts. Furthermore, because backsteps are performed while carrying a heavy weight on the back and shoulders, the toe break position of the shoes must be optimized so that the center of gravity does not shift forward and the feet can walk back without wobbling, while maintaining overall balance. Furthermore, to facilitate the lateral arch function and flex the foot joints, the traditional Japanese zori sandal shape, which allows the toes to move as if barefoot, is optimal.

[0039] The inventors have noted that it is important to maximize the arch function of the sole of the foot during backsteps and knee flexion and extension, and that the position of the MP joint is the optimal toe break position when backstepping. They have discovered that in order to optimize the toe break position and maximize the arch function of the sole of the foot, the shoe should have a wide toe box mechanism resembling the shape of a Japanese sandal. Therefore, the inventors have developed a lifting shoe 1 called a "wide toe box shoe" that achieves both the trade-off between preventing the foot from wobbling and making it easy to bend the joints of the foot. Here, "wide toe box shoes" refer to shoes that, when worn, have a sufficient area around the toes, allowing all toes to move freely, and the toe break position is at the MP joint position.

[0040] The inventors of the present invention have designed the sole shape of the outsole forefoot portion 110 of the lifting shoe 1 to have an enlarged sole portion 115, thereby creating a configuration that allows for appropriate flexibility at the MP joint α. Therefore, the lifting shoe 1 ensures foot stability by suppressing wobble of the foot F within the shoe, preventing both feet supporting the weight load from wobbling during backsteps and knee bending and extension. The lifting shoe 1 optimizes the center of gravity during backsteps and maximizes the force pushing against the floor G and the reaction force from the floor G during knee bending and extension, ensuring the flexibility of the ankle joint, ensuring ease of bending the foot from the MP joint α.

[0041] As shown in Figures 14 and 15, the lifting shoe 1 causes the toe break to occur at the MP joint α, which is the optimal toe break position TP, and the foot F is bent appropriately from the MP joint α. The location of the toe break position TP varies depending on the size of the foot F, but it is generally located approximately 70 mm from the toe position. Furthermore, the second strap 27 is positioned so as not to interfere with the toe break area TPA, which includes the toe break position TP, allowing the toe break to occur at the optimal toe break position TP. In addition, the reinforcing plate 117 has a plate connecting portion 117c that is configured as a constricted shape with a smooth concave curve. This creates a difference in bending rigidity between the plate connecting portion 117c, where the bending rigidity is lower than the bending rigidity of the first plate portion 117a and the second plate portion 117b, promoting appropriate foot bending deformation from the MP joint α.

[0042] As a result, lifting shoes 1 exhibit a transverse arch function, allowing the user to perform movements with the rigidity (stability) of outsole forefoot portion 110 fully realized, enabling stable backsteps with an optimized center of gravity and no wobbling of the foot. Furthermore, lifting shoes 1 simultaneously prevent the foot from wobbling and ensure flexibility of the foot joints for bending. As a result, lifting shoes 1 maximize the force pushing against the floor G and the floor reaction force from the floor G, both when squatting from an upright position and when standing up from a bent knee (squatting position), thanks to outsole forefoot portion 110 with reinforcing plate 117. This allows lifting shoes 1 to lift heavier barbells compared to conventional products 1 and 2.

[0043] The foot stabilization effect of the transverse arch is achieved by setting the expanded sole width dimension FW of the outsole forefoot portion 110 to the standard sole width dimension SW of the reference foot shape plus the medial expanded width ΔWin and the lateral expanded width ΔWout, and by providing a reinforcing plate 117 in the toe area (see FIG. 9 ). That is, the outsole forefoot portion 110 exhibits the transverse arch function by ensuring space that allows for easy bending from the MP joint α, thereby enhancing torsional resistance. Additionally, the outsole forefoot portion 110 is provided with a reinforcing plate 117 that increases rigidity in the toe area, including the area corresponding to the MP joint α, thereby suppressing sinking in a twisted state toward the medial or lateral side of the foot F. This suppresses wobble in the transverse direction of the foot during squats under heavy loads, ensuring foot stability.

[0044] Furthermore, the sole width of the toe sole portion 116 at the toe division line JL is wider than the sole width at the toe division line JL in the standard sole shape SS. In addition, the toe sole portion 116 is set to a sole shape in which the reduction rate of the sole width from the toe division line JL toward the toes is less than the reduction rate of the sole width in the standard sole shape SS. As a result, the toe sole portion 116 ensures enough space for the five toes to easily bend from the knuckles and spread apart.

[0045] In this way, the lifting shoe 1 exhibits the transverse arch function by forming an MP joint accommodation space around the foot F that ensures free movement of the MP joint α through the setting of the expanded sole width dimension FW in the outsole forefoot portion 110. Furthermore, the lifting shoe 1 exhibits the lateral longitudinal arch function and medial longitudinal arch function by forming a toe accommodation space that allows the five toes to easily bend from the MP joints and ensures free movement through the shape setting of the toe sole portion 116. Therefore, the lifting shoe 1 exhibits all of the transverse arch function, lateral longitudinal arch function, and medial longitudinal arch function, thereby maximizing the function of the plantar arch.

[0046] [Effects of lifting shoes] The lifting shoes 1 of the first embodiment can achieve the following effects.

[0047] (1) A lifting shoe 1 includes a sole 10 and an upper 20 fixed to the sole 10 and covering the upper portion of the wearer's foot. The sole 10 has a sole region division line DL set at a position closer to the heel than the MP joint α, which bends between the metatarsal and phalanges at the base of the toes of the foot F. The sole region division line DL divides the entire sole region SA into a forefoot region FA on the toe side and a rearfoot region BA on the heel side. The sole 10 includes an outsole 11 having a contact surface 111 with the floor G or ground, and a midsole 12 fixed on top of the outsole 11. The outsole 11 has an outsole forefoot portion 110 in the forefoot region FA, which includes an area corresponding to the MP joint α. When a reference sole shape SS is defined as a circumferential foot shape drawn along the outline of the wearer's foot F, the outsole forefoot portion 110 is set to have an enlarged sole portion 115 whose sole area expands outward from the periphery of the reference sole shape SS. This lifting shoe 1 can ensure both foot stability and ankle flexibility while walking and bending and straightening the knees while supporting a weight load with both feet.

[0048] (2) The outsole 11 is provided over the entire sole area SA, which is the combination of the forefoot area FA and the rearfoot area BA. The midsole 12 is provided in the rearfoot area BA. The outsole forefoot part 110 is set to have a bending rigidity that allows plantar flexion and dorsiflexion of the foot F from the MP joint α. This lifting shoe 1 allows free plantar flexion and dorsiflexion of the foot F due to the setting of the bending rigidity of the outsole forefoot portion 110. This ensures that when bending the foot F under a heavy load, the foot can be properly bent from the position of the MP joint α, which is the natural movement of the foot.

[0049] (3) The outsole is made of a high-hardness rubber material. The outsole forefoot portion 110 is provided with a reinforcing plate 117 made of a material harder than the high-hardness rubber material in the toe area including the area corresponding to the MP joint α. In this lifting shoe 1, the reinforcing plate 117 performs the roles of adjusting the bending rigidity of the forefoot region FA of the outsole 11, suppressing sinking when the foot F is in a twisted state, and improving the force pushing against the floor G and the floor reaction force from the floor G.

[0050] (4) The reinforcing plate 117 has a first plate portion 117a located on the heel side of the boundary region corresponding to the MP joint α, and a second plate portion 117b located on the toe side of the boundary region. The vertical bending rigidity of the first plate portion 117a of the reinforcing plate 117 is set to be higher than the vertical bending rigidity of the second plate portion 117b. The plate shape of the reinforcing plate 117 is set so that the shape of the plate connecting portion 117c connecting the first plate portion 117a and the second plate portion 117b is set to be a constricted shape. In this lifting shoe 1, the plate connecting portion 117c of the reinforcing plate 117 is configured to have a constricted shape, thereby promoting appropriate bending deformation of the foot from the MP joint α.

[0051] (5) The expanded sole width dimension FW of the outsole forefoot portion 110 is the standard sole width dimension SW of the standard sole shape SS plus an expanded medial width ΔWin expanded inward from the standard sole shape SS and an expanded lateral width ΔWout expanded outward from the standard sole shape SS. The expanded sole portion 115 is set to a shape in which the expanded medial width ΔWin and the expanded lateral width ΔWout gradually expand from the sole region division line DL toward the region corresponding to the MP joint α. This lifting shoe 1 has a space for accommodating the MP joint, which can be easily bent from the MP joint α, and the MP joint α can be positioned at the toe break position TP, thereby enabling the transverse arch function to be exerted.

[0052] (6) In the outsole forefoot portion 110, a toe division line JL is set at a predetermined distance inside the front tip position of the outsole to divide the toe area, and the portion formed by reducing the sole width from the toe division line JL toward the toe is the toe sole portion 116. In this toe sole portion 116, the sole width at the toe division line JL is wider than the sole width at the toe division line JL in the standard sole shape SS, and the reduction ratio of the sole width from the toe division line JL toward the toe is set to a sole shape that is smaller than the reduction ratio of the sole width in the standard sole shape SS. The lifting shoes 1 have a toe accommodation space that allows the five toes of the foot F to bend easily from the MP joint α and ensure free movement, and maximizes the function of the plantar arch by demonstrating the transverse arch function, lateral longitudinal arch function, and medial longitudinal arch function.

[0053] (7) The upper 20 includes at least one strap (first strap 26, second strap 27) in the width direction of the foot. The strap (second strap 27) is set at a position that avoids interference with the front and rear toe break areas TPA including the MP joint α when the upper 20 bends from the position corresponding to the MP joint α. In this lifting shoe 1, the strap (second strap 27) does not become a factor that inhibits bending of the upper 20 from the position corresponding to the MP joint α, and bending from the MP joint α can be ensured.

[0054] (8) The upper 20 is fixed integrally along the opening lower end facing the sole 10 and is provided with a sole cover 30 having a shape that matches the sole surface shape of the sole 10. The sole cover 30 uses a material that is more flexible than the material of the midsole 12, and the bottom surface of the cover is adhesively bonded to the sole surface of the sole 10. In this lifting shoe 1, the sole cover 30 is attached to the surface of the sole 10, thereby reducing pain on the sole caused by the unevenness of the sole surface, and improving the comfort of use.

[0055] The above explanation is based on the drawings of the lifting shoe 1 of embodiment 1. However, the specific configuration of the shoe of the present disclosure is not limited to the configuration shown in embodiment 1. The shoe of the present disclosure is permissible to be modified or added to in design as long as it does not deviate from the gist of the invention according to each claim of the scope of the claims.

[0056] In the first embodiment, an example was shown in which the sole region demarcation line DL is set on the heel center line CL2 at a position closer to the heel than the MP joint α and is a line perpendicular to the heel center line CL2. However, the sole region demarcation line is not limited to this setting example, and may be set, for example, on the shoe center line at a position closer to the heel than the MP joint and is a line perpendicular to the shoe center line. Also, the sole region demarcation line may be set on the toe center line at a position closer to the heel than the MP joint and is a line perpendicular to the toe center line. Furthermore, the sole region demarcation line may be set not as a straight line but as a bent line, curved line, or the like.

[0057] In the first embodiment, an example was shown in which the outsole is made of a high-hardness rubber material and is provided with a reinforcing plate 117 made of a material harder than the high-hardness rubber material in the toe area including the area corresponding to the MP joint α of the outsole forefoot portion 110. However, the outsole may not be provided with a carbon plate. In the example in which a carbon plate is not provided, the outsole can be used to adjust bending rigidity, suppress sinking, improve floor reaction force, etc., by selecting the outsole material, setting the sole thickness, setting the sole shape, etc.

[0058] In the first embodiment, the shape of the plate joint 117c on the outer side of the foot width of the reinforcing plate 117 is set to a one-sided constricted shape with a smooth concave curve. However, the shape of the carbon plate is not limited to this. For example, the shape of the plate joints on the inner and outer sides of the foot width of the carbon plate may be set to a constricted shape on both sides. Also, instead of the smooth concave curve, the shape of the plate joint may be set to a constricted shape with a jagged pattern along the concave shape. Furthermore, instead of the smooth concave curve, the shape of the plate joint may be set to a constricted shape with a straight triangular recess.

[0059] In the first embodiment, an example was shown in which the sole cover 30, which is made of a material that is softer than the material of the midsole 12, has its bottom surface adhesively bonded to the sole surface of the sole 10. However, the present invention is not limited to an example in which the sole cover 30 is adhesively bonded to the sole surface, and for example, an insole, which is a removable accessory, may be attached to the sole cover. In the example in which this insole is attached, multiple types of insoles with different thicknesses and sizes are prepared in advance, allowing the wearer to select one according to their preferences, etc.

[0060] In the first embodiment, the shoe is an example of application to a lifting shoe. However, the application of the shoe is not limited to a lifting shoe for powerlifting, weightlifting, etc. The shoe may be, for example, other sports shoes or indoor shoes that do not require much foot push-off or lift-off from the floor or ground, and where cushioning or shock absorption is not important. [Explanation of symbols]

[0061] 1. Lifting shoes (example of shoes) 10 soles 11 Outsole 110 outsole forefoot 111 Contact surface 113 Outsole surface 115 Enlarged sole 116 Toe sole 117 Reinforcement Plate 117a First plate section 117b Second plate section 117c Plate joint 12 Midsole 121 Midsole surface 20 Upper 26 First Strap 27 Second Strap 30 Sole Cover G Floor surface F foot α MP joint DL sole area dividing line SA sole entire area FA forefoot area BA hindfoot area SS standard sole shape FW Expanded sole width dimensions SW standard sole width dimensions ΔWin Inner Expanded Width ΔWout Outer expansion width P1 Toe position JL Toe Divider

Claims

1. A shoe comprising a sole and an upper fixed to the sole and covering an upper portion of a wearer's foot, The sole has a sole region dividing line set at a position closer to the heel than the MP joint, which bends at a position between the metatarsal bone and the phalanges at the base of the toes, and the sole region dividing line divides the entire sole region into a forefoot region on the toe side and a rearfoot region on the heel side, The sole includes an outsole having a contact surface with a floor or ground, and a midsole fixed on the outsole, The outsole has an outsole forefoot portion in the forefoot region including an area corresponding to the MP joint, When a circumferential foot shape drawn along the outline of a wearer's foot is taken as a reference sole shape, the forefoot portion of the outsole is set to have a sole shape having an enlarged sole portion whose sole area is enlarged outward from the periphery of the reference sole shape, The outsole is provided over the entire sole area including the forefoot area and the rearfoot area, the midsole in the rearfoot region, The outsole forefoot portion has a bending rigidity that allows plantar flexion and dorsiflexion of the foot from the MP joint, The material of the outsole is a high-hardness rubber material, The forefoot portion of the outsole is provided with a reinforcing plate made of a material harder than the high-hardness rubber material in a toe area including an area corresponding to the MP joint. These shoes are characterized by:

2. In the shoe described in claim 1, The reinforcing plate includes a first plate portion on the heel side of a boundary region corresponding to the MP joint, a second plate portion located on the toe side of the boundary area, The reinforcing plate has a first plate portion having a higher bending rigidity in the vertical direction than a second plate portion, The reinforcing plate has a plate connecting portion that connects the first plate portion and the second plate portion and is configured to have a constricted shape. These shoes are characterized by:

3. In the shoes described in claim 2, the outsole forefoot portion has an expanded sole width dimension obtained by adding an inner expanded width expanded inward from the standard sole shape and an outer expanded width expanded outward from the standard sole shape to the standard sole width dimension of the standard sole shape, The expanded sole portion is set to a shape in which the inner expanded width and the outer expanded width gradually expand from the sole region dividing line toward the region corresponding to the MP joint. These shoes are characterized by:

4. In the shoes described in claim 3, When a toe division line is set in the outsole forefoot portion at a predetermined inner position from the front tip position of the outsole to divide the toe portion, and the portion formed by narrowing the sole width from the toe division line toward the toe is defined as a toe sole portion, The toe sole portion is configured to have a sole width at the toe division line that is wider than the sole width at the toe division line in the reference sole shape, and a reduction ratio of the sole width from the toe division line toward the toe that is smaller than the reduction ratio of the sole width in the reference sole shape. These shoes are characterized by:

5. In the shoes described in any one of claims 1 to 4, The upper includes at least one strap extending in a width direction of the foot, The strap is set at a position that avoids interference with the front and rear toe break regions including the position when the upper is bent from the position corresponding to the MP joint. These shoes are characterized by:

6. In the shoe according to claim 5, the upper is integrally fixed along an opening lower end portion facing the sole, and includes a sole cover having a shape that matches the sole surface shape of the sole; The sole cover is made of a material that is softer than the material of the midsole, and the bottom surface of the cover is adhesively bonded to the sole surface of the sole. These shoes are characterized by:

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