Footwear having function of correcting posture of human body

Abstract

The present invention provides footwear that has a function adjusting a human body's posture such that it enables a bow-legged or knock-kneed user to land naturally from the heel during walking and to walk while the gravity center moves along an outwardly curved zone. The footwear comprises a sole and a cover part that covers the instep of the foot, and the sole has a toe portion and a heel portion on which the heel is placed. Assuming that the sole is divided into an inner portion including the thumb of the foot and an outer portion including the little finger, a flat thick area is provided on the inner portion, and the other portion of the sole is made to be a flat thin area. The thick area extends from the toe portion to a portion facing the medial longitudinal arch of the foot through a portion respectively facing the thumb and the base portion of the thumb. The thin area continuously extends in the longitudinal direction of the sole from a portion respectively facing the middle finger, the ring finger, the little finger of the foot, and each base portion of the middle finger, the ring finger, and the little finger to the heel portion through a portion facing a lateral longitudinal arch of the foot.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to footwear comprising a sole part on which a user's foot is placed and an upper part covering the user's foot, such as sandals, and particularly relates to the footwear having a function for correcting a human body's posture.BACKGROUND OF THE INVENTION

[0002] Footwear such as sandals is generally configured by attaching an upper part such as a belt or a thong to a flat-plate-shaped sole with a foot sole shape. In addition, sandals having various functions such as stimulating pressure points on a foot sole by projections provided on a bottom surface while walking have also been developed.

[0003] Patent Literature 1 discloses footwear having a sole, a front thong portion, and a thong portion, wherein the sole is formed by bonding a first layer having a thin portion onto a second layer without a thin portion, and wherein the thin portion of the first layer has a structure in which a portion in a little finger side with respect to the front thong portion and in a toe portion side with respect to a heel portion is omitted. According to this structure, when a user walks while wearing the footwear, the gravity center of the user's foot can be corrected to an inner side, and the distance between the knees of a bow-legged user can be narrowed. Patent Literature 1 also discloses the footwear in which a heel area of the sole is cut off in an arc or straight line to make the user walk with his or her toes.

[0004] Patent Literature 2 discloses footwear comprising a sole part on which a user's foot is placed, an upper part covering an instep of the user's foot, and an inner sole part, wherein assuming that a foot sole of the user is divided into two portions of a toe side and a heel side in a vicinity of a plantar arch and the toe side is further divided into a thumb side (inner side) and a little finger side (outer side), a half portion of the little finger side (outer side) is configured to face a thin portion generally. Patent Literature 2 also describes an example in which a portion facing the heel portion of the foot sole is made into a missing portion. Since the footwear described in Patent Literature 2 has the missing portion, the user is placed in a walking position on tiptoe so that walking with the footwear allows the muscles of the calves, backs of the thighs, and the buttocks to be naturally exercised.PRIOR ARTPATENT LITERATURES

[0005] Patent Literature 1: JP 7166035 B Patent Literature 2: JP 7454299 B SUMMARY OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTION

[0006] Landing with the heel of a foot when walking with footwear (heel landing) has been shown to have several advantages. First, by landing with the heel and then receiving an impact of the ground on an entire foot, the impact on the foot, knees, and hips can be alleviated. In addition, the heel landing facilitates stabilization of the gravity center of a body, facilitates balance during walking, and reduces the risk of falling. Further, the heel landing disperses a load on the muscles and joints of the entire foot, making it relatively difficult to tire even after walking for a long time. Furthermore, the heel landing and then pushing the ground using the entire foot sole can reduce energy loss and increase walking efficiency.

[0007] The feet of a bow-legged person tend to tilt outward during walking because the knees are in a state of spreading outward. Therefore, an excessive load is applied to the outer side of a heel or the outer side of the foot, landing from the heel is made unstable, and the landing is biased toward a toe or the inner side of the foot in many cases. Such a landing results in a forward gravity center so that the muscles of the front thighs are used, tending to make the thighs thicker. In addition, it is difficult to maintain balance during walking, and walking tends to be unstable. Further, the ankle joints are overloaded, and if such overloading is left untreated, it can lead to osteoarthritis of the knees.

[0008] On the other hand, the feet of a knock-kneed person may tilt to the inner side during walking because the knees are in a state of leaning to the inner side, pressure is likely to concentrate on the inner side of the foot or the toe, an excessive load is applied to the inner side of the heel or the inner side of the foot, and landing from the heel may be biased. In addition, the weight tends to be biased to one side, it is difficult to maintain balance, walking is made to be unstable, and the risk of falling may increase.

[0009] Each invention disclosed in Patent Literatures 1 and 2 has a configuration in which a user walks with his / her toes and thus has a function of correcting bowlegs while having a simple structure. However, the disadvantage that a bow-legged person is unstable in landing from the heel is not sufficiently improved. Moreover, Patent Literatures 1 and 2 do not refer to a knock-kneed user.

[0010] An object of the present invention is to provide footwear that has a simple structure and a function making it easier to maintain balance and adjust a human body's posture such that it enables a bow-legged or knock-kneed user to land naturally from the heel during walking and to smoothly shift a body's gravity center from the heel to the toe with making the gravity center move along an outwardly curved zone. Further, another object of the present invention is to provide footwear that is designed such that the knees of a user face forward whether the user stands or walks while wearing the footwear, and that the user's pelvis is tightened just by standing while wearing the footwear, thereby supporting the user to have a correct posture just by standing while wearing the footwear. Furthermore, still another object of the present invention is to provide footwear that has a step of the unevenness of an insole to change a landing location, a landing order, and so on of a foot sole when a user walks so that the user can walk while using original correct muscles and skeletons, and supports the user to be able to perform a correct standing and a correct walking so that the muscles and skeleton return to correct positions for the health of the human body.MEANS FOR SOLVING THE PROBLEMS

[0011] According to one aspect of the present invention, footwear of the present invention comprises a sole on which a foot is placed and a cover part that covers an instep of the foot, the sole being shaped around a circumference of the foot and having a toe portion and a heel portion on which a heel is placed, characterized in that, assuming that the sole is divided into an inner portion including the thumb of the foot and an outer portion including the little finger, a flat thick area is provided on the inner portion, and the other portion of the sole is made to be a flat thin area, that the thick area extends in a longitudinal direction of the sole from the toe portion to a portion facing the medial longitudinal arch of the foot through a portion respectively facing the thumb and the base portion of the thumb, and that the thin area continuously extends in the longitudinal direction of the sole from a portion respectively facing the middle finger, the ring finger, the little finger of the foot, and each base portion of the middle finger, the ring finger, and the little finger to the heel portion through a portion facing the lateral longitudinal arch of the foot.

[0012] According to the present invention, the footwear is configured such that when a user walks while wearing the footwear, the user first lands with the heel portion facing the thin area of the sole, and the user's weight moves from the heel portion to an inside portion of the thick portion where a thong exists through the portion facing the lateral longitudinal arch of the foot and an outside portion of the toe portion. Thus, it allows the user's gravity center to shift smoothly from the heel of the foot to the toe portion through the inside while the gravity center moves along an outwardly curved zone. In addition, a portion facing the medial longitudinal arch (plantar arch) of the foot is the thick area to prevent the gravity center of the user's foot from biasing too inward. Therefore, even when the user is bow-legged or knock-kneed, the user's weight smoothly moves from the heel portion to the toe portion while the gravity center moves along the outwardly curved zone. As a result, the user's posture during walking can be kept correct, and consequently, the body's posture can be adjusted. When the user stands and walks while wearing the footwear, the footwear supports the user in performing correct walking so that the muscles and skeleton return to the correct positions for the health of the human body. When a bow-legged or knock-kneed user uses the footwear continuously, the user can adjust the human body's posture and walk while unconsciously landing with the heel so that the abdominal muscles are strengthened and the hips and the pelvis are tightened because the knees face outward.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Fig. 1 is a perspective view showing the appearance of footwear according to a first embodiment of the present invention. Fig. 2A is a plan view of a pair of footwear according to the first embodiment. Fig. 2B is a drawing showing a relation between the footwear of the first embodiment and a user's foot sole. Fig. 3 is a side view of the footwear according to the first embodiment. Fig. 4 is a rear view of the footwear according to the first embodiment. Fig. 5 is an image drawing showing a movement state of the main contact areas (C) where the user's foot sole contacts the footwear and a movement state of a gravity center position (G) where the weight (gravity center) of the user largely acts on the footwear when the user walks while wearing the footwear according to the first embodiment. Fig. 6 is a drawing showing a desirable walking situation of a bow-legged or knock-kneed user wearing the footwear of the present invention to perform walking training. Fig. 7 is another drawing showing the desirable walking situation of the bow-legged or knock-kneed user wearing the footwear of the present invention to perform walking training. Fig. 8 is a front view showing the state of the skeleton when the bow-legged user walks. Fig. 9 is a front view showing the state of the skeleton when the bow-legged user wearing the footwear of the present invention stands upright. Fig. 10 is a side view showing the state of the skeleton when the bow-legged user wearing the footwear of the present invention stands upright. Fig. 11 is a perspective view showing the appearance of footwear according to a second embodiment of the present invention. Fig. 12 is a side view of the footwear according to the second embodiment. EMBODIMENTS OF THE INVENTION

[0014] Hereinafter, the present invention is explained in detail by referring to embodiments according to the drawings.[First Embodiment]

[0015] Fig. 1 is a perspective view showing the appearance of footwear according to a first embodiment of the present invention, and Fig. 2A is a plan view of a pair of footwear. Fig. 2B is a drawing showing a relation between the footwear and a user's foot. The footwear 1 is a so-called beach sandal and comprises a sole 10 on which a user's foot is placed and a thong 20 that functions as a cover part covering an instep of the foot. Fig. 1 shows the footwear 1 to be worn on the user's left foot. The pair of footwear 1 has a right footwear 1R and a left footwear 1L symmetrical with each other (see Fig. 2A).

[0016] The sole 10 is a flat plate-shaped member shaped around the circumference of the foot and formed of rubber material, an EVA urethane material, or the like, and comprises a heel portion 10a on which the heel 202 of the foot 200 of the user is placed and a toe portion 10b on which the toe 201 of the foot 200 of the user is placed. The sole 10 has a flat thick area 120 in an inner portion and a flat thin area 100 in the other portion. A boundary portion 130 between the thick area 120 and the thin area 100 is made to be a chamfered inclined surface.

[0017] The thong 20 is made of cloth or synthetic resin and comprises a front thong portion 21 and a lateral thong portion 22. The front thong portion 21 is disposed on the toe portion 10b of the sole 10 and is made to extend upward from a plate surface of the sole 10 to be interposed between the thumb 204 and the index finger 205 of the user's foot 200. The lateral thong portion 22 is constituted by a string-like or band-like member made of cloth or synthetic resin and is divided into two portions, i.e., an inner lateral thong portion 22a extending toward a side portion (hereinafter, referred to as an inner side portion) on the thumb side on the sole 10 from the front thong portion 21 as a base end, and an outer lateral thong portion 22b extending toward a side portion (outer side portion) on the little finger side. Respective terminal end portions 22e of the inner lateral thong portion 22a and the outer lateral thong portion 22b are fixed to both sides of a plantar arch area of the sole 10. The thick area 120 extends in a tongue-like shape in a longitudinal direction of the sole 10 from the toe portion 10b of the sole 10 to position 122 corresponding to an inner side of the terminal end portions 22e of the lateral thong portion 22.

[0018] Fig. 2B is a drawing showing a relation between the footwear 1 and the user's foot 200. Assuming that a line segment connecting the front thong portion 21 of the footwear 1 and the center of the heel portion 10a on which the heel 202 of the user's foot 200 is placed is a center line O-O, the thick area 120 of the sole 10 extends in the longitudinal direction from an inner portion of the toe portion 10b, i.e., a portion facing the thumb 204 and the base portion thereof, to a boundary portion 130 facing the medial longitudinal arch (plantar arch) 207 of the foot 200, slightly beyond the center line O-O in the transverse direction. That is, the thick area 120 is slightly wide in a lateral direction of the sole 10 in each vicinity of positions corresponding to the toe side of the front thong portion 21 and the inner side of the terminal end portions 22e of the lateral thong portion 22, and is slightly narrow at an intermediate position between them. On the other hand, the thin area 100 continuously extends in the longitudinal direction of the sole 10 from the portion of the toe portion 10b, that is, the portion facing the middle finger, ring finger, little finger 206, and the base portion thereof of the foot to the heel portion 10a through a portion facing the lateral longitudinal arch 208 of the foot. The heel portion 10a is flat without a thick area and is sufficiently large to receive the heel 202 of an unbalanced bow-legged or knock-kneed user.

[0019] Fig. 3 is a side view of the footwear 1, and Fig. 4 is a rear view of the footwear 1. The thin area 100 of the sole 10 has a sufficient thickness to absorb impact forces on the foot during the heel landing. For example, it has a thickness of about 25 mm to 35 mm depending on the size of the footwear 1. The thick area 120 of the sole 10 has a thickness H of, for example, 10 mm to 25 mm, depending on the size of footwear 1. Accordingly, the surface of the thick area 120 has a height of, for example, about 50 mm from the bottom surface of footwear 1.

[0020] The toe portion 10b of the sole 10 is inclined to be higher than the other surface of the thick area. That is, the toe portion is made to be an inclined surface 10C of which the tip is further higher than the thickness H of the thick area 120. Depending on the size of footwear 1, the tip of the inclined surface 10C is, for example, about 10 mm higher than the plane having the thickness H which forms the main part of thick area 120. This is to prevent the toe of the user's foot from slipping forward due to a wedge effect of the inclined surface 10C of the sole 10 in the sandal 1 without a cover.

[0021] Fig. 5 is an image drawing showing a movement state of the user's weight on the footwear when the user walks while wearing the footwear according to the first embodiment. That is, Fig. 5 is the image drawing showing a movement state of the main contact areas (C) where the user's foot sole contacts the footwear 1 and a movement state of a gravity center position (G) where the weight (gravity center) of the user largely acts on the footwear 1 when the user walks while wearing the footwear. Assuming that the user's foot sole is divided into two portions of the toe side and the heel side in the vicinity of the plantar arch and the toe side is further divided into the thumb side (inner side) and the side of the middle finger, ring finger, and little finger (outer side) of the foot, a portion (C3) of a transverse head adductor hallucis muscle positioned in the "outer side" portion of the foot sole and a portion (C2) of a flexor digiti minimi brevis muscle of foot on a lateral side of the plantar arch generally face the thin area 100. During walking, the user wearing the footwear of the present invention first lands on the heel portion 10a (C1), which is a thin area, from the heel. At this time, the gravity center of the user's weight also acts on the heel position (G1) which is the same as (C1). When the user walks while wearing the footwear 1 of the present invention, the main contact area between the user's foot sole and the footwear 1 moves forward along an outwardly curved zone which is along the thin areas (C2), (C3) facing the outer side of the foot sole, and finally lands on the "outer" thumb toe portion (C4). In addition, a concentration position of the user's weight also moves forward along the outwardly curved zone in the same manner as the main contact area. That is, the gravity center of the user's weight also moves forward along the outwardly curved zone from the heel position (G1) of the foot sole to (G4) through (G2), (G3). By directing the user's gravity center from the heel position (G1) toward the portions (G2), (G3) facing the thin areas in this way, it is possible to prevent the gravity center from being unevenly distributed on the front side.

[0022] The thick area 120 faces the vicinity of the plantar arch 207 of the foot sole. This thick area 120 contacts the plantar arch of the user's foot and prevents the user's foot from tilting too inward owing to an inner gravity center. This allows the gravity center of the user's foot to be guided to the thumb portion (G4) from the heel portion (G1) without being guided too inward. That is, even when the user is bow-legged or knock-kneed, it is possible to appropriately maintain an interval between the user's knees and bring a walking form closer to a standard form.

[0023] When a bow-legged or knock-kneed user wears the footwear 1, the gravity center is located on the heel in a stationary state, the skeletal structure is aligned, and a correct posture is achieved. The user's pelvis is tightened when the user simply stands while wearing the footwear 1, for example, sandals. The user is supported to maintain a correct posture when the user simply stands while wearing the sandals. Further, a step of the unevenness is formed on the surface of the sandals by the thin area 100 and the thick area 120, and a landing place, a landing order, and the like of each foot sole during walking are changed by the step of the unevenness, and thus it is possible to walk while using an original correct muscle or skeleton of each foot of the user. Therefore, by walking while maintaining the correct posture, the muscles of the user to be used are changed, and it is possible to obtain effects that the user's buttocks and pelvis are tightened. However, unless consciousness is changed, even though a bow-legged or knock-kneed user walks while wearing the footwear 1, the desired effects will not necessarily be obtained. Walking training for successfully wearing this footwear 1 is necessary. That is, walking training with a consciousness of heel landing is required (see Figs. 6 and 7).

[0024] According to the present embodiment configured as described above, when a bow-legged user wears the footwear 1, it is capable of making the gravity center of each foot of the user move from the heel to the toe along an appropriate outwardly curved zone, and the interval between the user's knees can be corrected to a value close to the standard. Further, when a knock-kneed user wears the footwear 1, it is possible to suppress the user's weight to excessively concentrate on the inner side portion of the foot sole, and it is possible to correct the interval between the user's knees to a value close to the standard. When the user stands and walks while wearing the footwear 1, the sandals of the present invention support the user to be able to walk correctly such that the muscles and skeletal structure return to each correct position for physical health.

[0025] Figs. 6 and 7 are drawings showing a desirable walking situation of a bow-legged or knock-kneed user wearing the sandals which are the footwear of the present invention to perform walking training. As shown in Fig. 6, the user wearing the footwear 1 needs to land on the heel portion 10a which is the thin area, from the heel of the left foot 200 during walking, for example (Point-1). Next, the outer half portion of the left foot 200 on the toe side comes into contact with the thin area 100 of the sole 10, and the user's gravity center is applied to the thin area of the footwear 1 (Point-2). Thereafter, the medial longitudinal arch (plantar arch) 207 of the left foot 200 comes into contact with the thick area 120 of the sole 10, the user's gravity center is applied to the thin area 100 of the footwear 1, and the gravity center of the left foot can be moved to the thumb portion. In the case of a knock-kneed user, an excessive gravity center is less likely to be applied to the thin area 100.

[0026] Further, as shown in Fig. 7, in a state in which the left foot is firmly held on the thin area and the thick area of the sole 10 of the footwear 1 (Point-3), the thumb portion of the right foot having the gravity center at the thumb portion finally leaves from the ground (Point-4). This is because the toe portion of the sole 10 is made to be the inclined surface 10C that is higher than the other surface of the thick area, so that the toe of the left foot is prevented from slipping forward, and the thumb portion of the right foot finally leaves the ground. In this way, even for a bow-legged or knock-kneed user, the gravity center of the foot of the user wearing the footwear 1 can be corrected to an appropriate position on the inner side. Therefore, it is ensured that the body weight smoothly moves from the heel portion to the toe portion through the lateral longitudinal arch of the foot during walking while the gravity center moves along the outwardly curved zone. In other words, even for a bow-legged or knock-kneed user, it is possible to easily walk while maintaining balance without the user's weight being biased to one side.

[0027] Fig. 8 is a drawing showing the state of the skeleton 300 of the human body as viewed from the front when a bow-legged user walks. When the bow-legged user wears a usual footwear, pressure tends to concentrate on the respective outer parts of the right and left feet 200R, 200L where the lateral longitudinal arches are respectively located, resulting in a poor posture in which the femurs 302 are twisted.

[0028] Fig. 9 is a drawing showing the state of the skeleton viewed from the front when the bow-legged user wearing the footwear of the present invention stands upright. When the user wears the footwear 1 of the present invention, as previously described, the user's weight moves from the heel of the foot to the thick area where the front thong portion exists through the inner side portion of the toe portion, that is, the thumb portion. Therefore, the user's legs are not made to be in the bow-legged state, and the correct posture as shown in Fig. 9 is maintained. Also in the case of a knock-kneed user, the user's legs are prevented from being in a knock-kneed state and the correct posture is maintained.

[0029] Fig. 10 is a drawing showing the state of the skeleton 300 viewed from the side when the bow-legged user wearing the footwear of the present invention stands upright. A "good posture" of a human body is said to be a state in which "ears, shoulders, hips, knees, and ankles" are aligned. When the bow-legged user wearing the footwear of the present invention stands upright, the posture is corrected to be straightened from the heel 202 of the foot 200 to the sternum 330. In addition, since the user can walk with an awareness of the heels 202 of the feet 200, the abdominal muscle 320 of the human body is strengthened. Further, since the knees face outward, the buttocks 310 and the pelvis are tightened.

[0030] Fig. 11 is a perspective view showing the appearance of footwear according to a second embodiment of the present invention. Fig. 12 is a side view of the footwear according to the second embodiment. This footwear comprises a sole part (sole) 10 on which a foot is placed and an upper part 23 that is fixed to the outer peripheral portion of the sole part to wrap around at least the instep of the foot placed on the sole part. As in the first embodiment, the sole part (sole) 10 has a thin area 100 and a thick area 120. The respective shapes of the thin area 100 and the thick area 120 are substantially the same as those of the footwear according to the first embodiment of the present invention. The upper part 23 is an alternative to the thong 20 of the first embodiment. Since the upper part 23 prevents the toe of the foot from slipping forward, the footwear of the second embodiment does not have a portion corresponding to the inclined surface 10C of the first embodiment. The respective shapes of the thin area 100 and the thick area 120 of the footwear according to the second embodiment are the same as those of the footwear according to the first embodiment except for the inclined surface, and the operations and effects thereof are also the same as those of the footwear according to the first embodiment.

[0031] As described above, the footwear of the present invention, while having a simple structure, has the function of enabling a bow-legged or knock-kneed user to land naturally from the heel during walking and to smoothly shift the body's gravity center from the heel to the toe with making the gravity center move along the outwardly curved zone, thereby making it easier to maintain balance and adjust the human body's posture. In addition, the footwear is designed such that the user's knees face forward whether the user stands or walks while wearing the footwear, and that the user's pelvis is tightened just by standing while wearing the footwear, thereby supporting the user to have a correct posture just by standing while wearing the footwear. Moreover, the footwear has the step of the unevenness of the insole to change the landing location, the landing order, and so on of the foot sole when the user walks so that the user can walk while using the original correct muscles and skeletons, and supports the user to be able to perform the correct standing and correct walking so that the muscles and skeleton return to the correct positions for the health of the human body. Furthermore, the step of the unevenness of the insole of the footwear of the present invention provides a structure that makes it easy to kick up with the thumb of the foot when the user walks.

[0032] Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments. For example, although the beach sandals have been described as an example in the above-described embodiment, the present invention can also be applied to sandals for a room or the like. In addition, although the foot plate is made of rubber material, an EVA urethane material, or the like, the material of the foot plate is not limited thereto. For example, it may be made of wood.REFERENCE SIGNS LIST

[0033] 1...footwear 10...sole 10a...toe portion 10b...heel portion 100...thick area 10d...thin area 20...cover part 20a...thong 21...front thong portion 22...lateral thong portion 22a...innerlateral thong portion 22b... outer lateral thong portion

Claims

1. Footwear comprising a sole on which a foot is placed and a cover part that covers an instep of the foot, the sole being shaped around a circumference of the foot and having a toe portion and a heel portion on which a heel is placed, characterized in that, assuming that the sole is divided into an inner portion including the thumb of the foot and an outer portion including the little finger, a flat thick area is provided on the inner portion, and the other portion of the sole is made to be a flat thin area, that the thick area extends in a longitudinal direction of the sole from the toe portion to a portion facing the medial longitudinal arch of the foot through a portion respectively facing the thumb and the base portion of the thumb, and that the thin area continuously extends in the longitudinal direction of the sole from a portion respectively facing the middle finger, the ring finger, the little finger of the foot, and each base portion of the middle finger, the ring finger, and the little finger to the heel portion through a portion facing the lateral longitudinal arch of the foot.

2. The footwear according to claim 1, wherein the footwear is configured such that when a user walks while wearing the footwear, the user's weight moves from the heel portion of the sole to a portion facing the base of the thumb through a portion respective facing the lateral longitudinal arch of the foot and the toe portion while the gravity center moves along an outwardly curved zone.

3. The footwear according to claim 1 or 2, wherein the thick area has a thickness of 10 mm to 25 mm further relative to the thin area depending on the size of the footwear, and a boundary portion between the thick area and the thin area is made to be a chamfered inclined surface.

4. The footwear according to claim 1 or 2, wherein the footwear is a sandal that comprises a thong having a lateral thong portion extending over the instep of the foot and the sole to which the lateral thong portion is attached and on which the foot is placed, and wherein the thick area extends from a tip portion of the sole to the portion facing the medial longitudinal arch of the foot through the portion respectively facing the thumb and the base portion of the thumb to have a terminal end portion at a coupling portion between the lateral thong portion and the sole.

5. The footwear according to claim 4, wherein the toe portion of the sole is inclined so as to be higher than the other surface of the thick area.

6. The footwear according to claim 1 or 2, wherein the footwear comprises a sole part on which the foot is placed and an upper part that is fixed to an outer peripheral portion of the sole part to wrap around at least the instep of the foot placed on the sole part.

Images