EP3056105A1

EP3056105A1 - Exercise shoe sole

Info

Publication number: EP3056105A1
Application number: EP13895363.3A
Authority: EP
Inventors: Kenji Sakamoto; Mai NAKATA; Keizo Nakanishi; Takayuki KAMEUCHI; Jun Takei
Original assignee: Asics Corp
Current assignee: Asics Corp
Priority date: 2013-10-08
Filing date: 2013-10-08
Publication date: 2016-08-17
Also published as: JPWO2015052768A1; EP3056105A4; WO2015052768A1; JP5591420B1

Abstract

A plate is provided located between an upper surface of the outsole and an upper surface of the mid sole and being continuous from a middle foot portion to a rear foot portion, the plate being formed by a material having a greater Young's modulus than the outsole and the mid sole, the mid sole includes: a low-hardness area provided in an area of a majority of the middle foot portion and a majority of the rear foot portion; and a high-hardness area arranged between a Chopart's joint and a rear end of a calcaneal bone, wherein where a medial side portion, a central portion and a lateral side portion are obtained by dividing the rear foot portion in three equal parts in a transverse direction perpendicular to a longitudinal axis of a foot, the high-hardness area is provided in at least a portion of the central portion and/or a portion of the lateral side portion, the high-hardness area having a greater hardness than that of the material forming the low-hardness area, wherein the plate is arranged continuously anterior to, directly below, and posterior to, the high-hardness area.

Description

TECHNICAL FIELD

The present invention relates to a shoe sole of an indoor shoe for handball, basketball, etc., and also to a shoe sole of an athletic shoe suitable for running outdoors or walking as an exercise.

BACKGROUND ART

For example, improvements to the cushioning property are being pursued for running, walking, etc..
In a shooting move in handball, one takes off on one foot. There is a demand for shoes allowing one to jump high on this one-foot takeoff.

CITATION LIST

PATENT LITERATURE

First Patent Document: JP2000-083705A (Abstract)
Second Patent Document: JP2005-279020A (Abstract)
Third Patent Document: JP2003-009903A (Abstract)
Fourth Patent Document: JP2006-000311A (Abstract)
Fifth Patent Document: JP2010-538788W (Abstract)

SUMMARY OF INVENTION

FIG. 6A is a side view schematically showing the movement of a conventional sole on the pivot foot during a jump shot in handball. Note that 1 denotes an outsole and 2 denotes a midsole.
For a one-foot jump, after the run (run-up), one transitions from heel contact HC, at which the rearfoot section of the pivot foot contacts the ground (the floor), to foot flat FF, at which the entire foot sole is in contact with the ground. In the transition from heel contact HC to foot flat FF, a brake is applied on the pivot foot, which cancels the inertia from the run.
However, the inertia from the run cannot be completely canceled out by the brake on the pivot foot, and the brake still acts on the pivot foot at heel rise, at which the heel comes off the floor from foot flat FF. This will result in a loss of the jumping ability.
Moreover, due to the inertia from the run, the center of gravity of the body (the gravity center of the body) will have moved anterior to the pivot foot, so that the jumping ability (power) will unlikely be fully exerted.
Another problem is that during the transition from heel contact HC to foot flat FF, one may feel an impact upon landing of the heel portion.
A first object of the present invention is to improve the cushioning property, and a second object thereof is to provide a structure of a shoe sole of an athletic shoe with which it is possible to increase the jump height in one-foot jump.
In one aspect, a shoe sole of the present invention includes:

an outsole 1 having a tread surface (a ground contact surface);
a mid sole 2 arranged above the outsole 1; and
a plate 3 located between an upper surface of the outsole 1 and an upper surface of the mid sole 2 and being continuous from a middle foot portion 5M to a rear foot portion 5R, the plate 3 being formed by a material having a greater Young's modulus than Young's modulus of material of the outsole 1 and Young's modulus of material of the mid sole 2, wherein:

the mid sole 2 includes:
a low-hardness (low hardness) area 20 provided in an area of a majority (more than half) of the middle foot portion 5M and a majority (more than half) of the rear foot portion 5R; and
a high-hardness (high hardness) area 21 arranged between a Chopart's joint (Chopart joint) JS and a rear end of a calcaneal bone BC, wherein where a medial side portion 2M, a central portion 2C and a lateral side portion 2L are obtained by dividing the rear foot portion 5R in three equal parts in a transverse direction X perpendicular to a longitudinal axis CL of a foot, the high-hardness area 21 is provided in at least a portion of the central portion 2C and/or at least a portion of the lateral side portion 2L;
a hardness of a foam body (foamed material) forming the high-hardness area 21 is greater than that of the low-hardness area 20; and
the plate 3 is arranged continuously anterior to, directly below, and posterior to, the high-hardness area 21. Herein, "between a Chopart's joint JS and a rear end of a calcaneal bone BC" means "between the frontmost (foremost) end of the Chopart's joint and the rear end of the calcaneal bone BC".

For example, in a jump shot in the game of handball, it is preferable to shoot from a position as close to the goal as possible while avoiding contact with the defense when shooting. That is, in the shot, it is preferable to brake with the pivot foot (with one foot) while running and make a one-foot jump from the takeoff position as vertically as possible. However, it is difficult to completely cancel out the inertia from the run by the brake on the pivot foot, and it is therefore inevitable that some of the inertia remains.
The deformation and the effect of the sole during a one-foot jump according to the present invention will be described with reference to drawings.
FIG. 6B is a side view schematically showing the deformation of the sole in a one-foot jump.
In a one-foot jump, first, contact with the ground (the floor) is made starting from the lateral part of the rear end of the heel of the pivot foot. During this heel contact HC, the low-hardness area 20, which is more flexible than the high-hardness area 21, is compressed diagonally, while the high-hardness area 21 is less likely to be compressively deformed, and the rear portion of the plate 3 is inclined diagonally. The plate 3 extends from the rearfoot portion 5R, passing under the high-hardness area 21, which is hard, reaching the middle foot portion 5M. Therefore, the plate 3 is bent (curved, flexurally deformed) so that the plate 3 as a whole protrudes downward to absorb the energy upon landing, and the impulse of the brake will increase. As used herein, "the impulse of the brake" means "the integral value of the force acting as the brake".
Subsequent to the heel contact HC, the cycle transitions to foot flat FF where the entire foot sole contacts the ground. During the heel contact HC, the plate 3 undergoes a flexural deformation, thereby compressively deforming the high-hardness area 21, thus further increasing the apparent hardness of the high-hardness area 21. Therefore, the plate 3 bends (curves) so as to protrude downward with the high-hardness area 21 serving as the fulcrum, but the heel portion side of the plate 3 is less likely to bend. As a result, when transitioning to the foot flat FF, after the exertion of the braking force in response to the heel portion contacting the ground, the entire surface of the foot sole will smoothly contact the ground.
During the foot flat FF, the bent plate 3 restores its original shape by being sandwiched between the foot sole and the floor surface. The restoration of the plate 3 increases the stepping force (vertical force) on the floor surface. The increase in the stepping force will contribute to the increase in the gripping force, and will increase the impulse of the brake.
The foot flat FF is followed by heel rise where the heel comes off the floor surface, and then the player jumps upward, with the entire foot sole coming off the floor surface.
Now, at the heel rise, if there remains a large portion of the inertia from the run, the center of gravity of the body will be located anterior to the foot, which makes it necessary to continue to apply the brake while exerting the upward jumping ability, thereby lowering the jump height.
On the other hand, at the heel rise, if the inertia from the run is small, the center of gravity of the body will be located generally directly above the foot, making it easier to exert the jumping ability. That is, according to the present invention, as described above, there is a large impulse of the brake, which will decrease the inertia from the run while transitioning from heel contact HC to foot flat FF, thereby increasing the jump height.
Another effect is that, as described above, while transitioning from heel contact HC to foot flat FF, the plate 3 is bent (curved) so as to protrude downward after the heel portion contacts the ground, bringing the outsole 1 into a rounded shape, so that the entire foot sole smoothly contacts the ground while the plate 3 functions like a leaf spring, thereby absorbing the impact at first strike by virtue of the deformation of the shoe sole including the plate 3. Therefore, the cushioning property will also be improved when running or walking.
According to the present invention, if the high-hardness area 21 is arranged anterior to the frontmost end of the Chopart's joint or is arranged posterior to the rear end of the calcaneal bone BC, the amount of compressive deformation of the plate 3 or the low-hardness area 20 will likely be insufficient during heel contact HC.
The phrase "the plate 3 being continuous from the middle foot portion 5M to the rear foot portion 5R" means that the plate 3 needs to have such continuity that the deformation received by the plate 3 in the rearfoot portion 5R is transmitted (transferred) to the middle foot portion 5M of the plate 3.
In another aspect of the present invention, a shoe sole includes:

an outsole 1 having a tread surface;
a mid sole 2 arranged above the outsole 1; and
a plate 3 located between an upper surface of the outsole 1 and an upper surface of the mid sole 2 and being continuous from a middle foot portion 5M to a rear foot portion 5R, the plate 3 having a greater Young's modulus than those of the outsole 1 and the mid sole 2, wherein:

mid sole

2

an easy-to-compress area 20A provided in an area of a majority (more than half) of the middle foot portion 5M and a majority (more than half) of the rear foot portion 5R; and
a hard-to-compress area 21A arranged between a Chopart's joint JS and a rear end of a calcaneal bone BC, wherein where a medial side portion 2M, a central portion 2C and a lateral side portion 2L are obtained by dividing the rear foot portion 5R in three equal parts in a transverse direction X perpendicular to a longitudinal axis CL of a foot, the hard-to-compress area 21A is provided in at least a portion of the central portion 2C and/or at least a portion of the lateral side portion 2L, the hard-to-compress area 21A having a greater compressive rigidity than a material forming the easy-to-compress area 20A; and
the plate 3 is arranged continuously anterior to, directly below, and posterior to, the hard-to-compress area 21A, and a lower surface of the plate 3 is attached to an upper surface of the outsole 1 anterior to and posterior to the hard-to-compress area 21A.

Also in this case, one may expect functions/effects similar to those of the first aspect described above. That is, similar effects may be obtained also when the easy-to-compress (easily compressible) area 20A and the hard-to-compress area 21A are formed by the plate 3, for example, without providing different hardnesses in the midsole 2.
However, when the low-hardness area 20 and the high-hardness area 21 are provided in the midsole 2, it will be easier to estimate the behavior of the plate 3, and the effects of improving the cushioning property and improving the jump height will be realized stably.
Note that the following preferred embodiments and combinations thereof can be employed also when the low-hardness area 20 is provided as the easy-to-compress area 20A and the high-hardness area 21 as the hard-to-compress area 21A.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a lateral side view of a shoe sole showing one embodiment of the present invention. Note that the medial side of the foot bone structure is shown in phantom line for ease of understanding of the invention.
FIG. 2 is a plan view showing a midsole according to the embodiment.
FIG. 3 is a bottom view of the midsole.
FIG. 4 is a perspective view showing the midsole as seen from a diagonally rear direction.
FIG. 5 is a perspective view showing the midsole as seen from the reverse side.
FIG. 6A is a cycle diagram showing positions up to immediately before a jump with an ordinary athletic shoe, and FIG. 6B is a cycle diagram showing positions up to immediately before a jump with an athletic shoe having the shoe sole of the embodiment.
FIG. 7A and FIG. 7B show test results.
FIG. 8 is a lateral side view of a shoe sole showing another example.

DESCRIPTION OF EMBODIMENTS

Preferably, the high-hardness area 21 is arranged between the Chopart's joint JS and a medial projection (a medial process) BC2 of a calcaneal tuberosity BC1; and
the low-hardness area 20 is arranged to at least extend anterior to the Chopart's joint JS and posterior to the medial projection BC2.
In such a case, the high-hardness area 21 is arranged anterior to the medial projection BC2 of the calcaneal tuberosity BC1, and therefore, the amount of compression of the low-hardness area 20 is sufficiently large, and the plate 3 will be able to bend (curve) easily.
Therefore, it is possible to further increase the jump height and the cushioning property.
Preferably, the high-hardness area 21 is arranged between a front end of the calcaneal bone BC and a rear end of the calcaneal bone BC; and
the low-hardness area 20 is arranged to at least extend anterior to the front end of the calcaneal bone BC and posterior to the rear end of the calcaneal bone BC.
In such a case, the high-hardness area 21 is arranged posterior to the front end of the calcaneal bone BC, and awkwardness will unlikely be felt on the foot sole due to the high-hardness area 21, which is hard.
Preferably, the high-hardness area 21 is arranged between a front end of the calcaneal bone BC and a medial projection BC2 of a calcaneal tuberosity BC1; and
the low-hardness area 20 is arranged to at least extend anterior to the front end of the calcaneal bone BC and posterior to the medial projection BC2.
In such a case, the amount of compression of the low-hardness area 20 during heel contact HC is sufficiently large, and the plate 3 will be able to bend easily. Therefore, it is possible to further increase the jump height and the cushioning property.
Moreover, the high-hardness area 21 is arranged posterior to the front end of the calcaneal bone BC, and the awkwardness will unlikely be felt.
Preferably, an average value W1 of a first width from a lateral end of the high-hardness area 21 to an opposite end of the high-hardness area 21 from the lateral end is set to 17% to 100% of a whole width W of the midsole 2 in an area where the high-hardness area 21 extends across.
If the first width W1 is less than 17% of the whole width W, the jump height may not increase sufficiently. On the other hand, the first width W1 will not be greater than the whole width W, and the maximum value of the first width W1 is 100% of the whole width W.
However, if the high-hardness area 21, which is hard, is provided extending over the whole width of the midsole 2, awkwardness may be felt while running, for example.
For such reasons, the first width W1 of the high-hardness area 21 is more preferably about 17% to 80% of the whole width W. Most preferably, the first width W1 of the high-hardness area 21 is about 30% to 67% of the whole width W.
Preferably, an average value H1 of a first height of the high-hardness area 21 is set to 25% to 150% of an average value H of a height over a whole width W of the midsole 2 in an area where the high-hardness area 21 is arranged.
If the average value H1 of the first height is less than 25% of the average value H of height over the whole width of the midsole 2, the jump height may not increase sufficiently.
Note that a large roll-up portion is normally provided in the rearfoot portion 5R of the midsole 2, and if the high-hardness area 21 is provided lopsided (positionally deviated) toward the roll-up portion, it may be about 150% of the average value H of height over the whole width.
Preferably, an average value of a flexural rigidity in dorsal flexion, of a front portion 30 of the plate 3 which is anterior to the high-hardness area 21 is greater than an average value of the flexural rigidity in dorsal flexion, of a rear portion 31 of the plate 3 which is posterior to the high-hardness area 21.
In such a case, the average value of the flexural rigidity of the rear portion 31 is less than that of the front portion 30, and the low-hardness area 20 of the midsole 2 in the rear portion 31 will easily be compressed substantially (greatly).
In such a case, the average value of the flexural rigidity of the front portion 30 is greater than that of the rear portion 31, and it will be possible to have a larger energy absorbed by the front portion 30 of the plate 3 bent during heel contact HC.
Therefore, in such a case, one can expect a further increase in the jump height.
Preferably, a width of the plate 3 is greater than a width of the high-hardness area 21.
In such a case, it will be possible to realize improvements to both a good wearability and a sufficient jump height. That is, it is preferred that the first width W1 of the high-hardness area 21 is relatively smaller than the whole width W as described above. On the other hand, it is preferred that the width of the plate 3, which functions like a leaf spring, is larger than the first width W1 of the high-hardness area 21.
Preferably, a front end of the plate 3 is arranged posterior to a front end of a ball O1 of a big toe.
If the plate 3 extends anterior to the front end of the ball O1 of the big toe, it may hinder the flexion of the MP joint, lowering the vertically kicking force, which may lower the jump height. For such reasons, the front end of the plate 3 is preferably set to be posterior to the MP (metatarsophalangeal) joints of the first to fifth toes.
Preferably, a front end of the plate 3 is set at a position posterior to a front end of a ball O1 of a big toe and anterior to a base of a metatarsal bone B14 of a big toe B1.
In such a case, the plate 3 is set at a position anterior to the base of the metatarsal bone B14 of the big toe B1, and therefore, the long front portion 30 of the plate 3 bends substantially, so that one can expect a further increase in the jump height.
Note that the base refers to a portion of each bone that is close to the posterior joint and that is slightly expanding to a greater thickness, and it is referred to also as the proximal head.
Preferably, a rear end of the plate 3 is set at a position posterior to a medial projection BC2 of a calcaneal tuberosity BC1.
In such a case, it is possible to ensure a sufficient amount of protrusion by which the plate 3 protrudes (projects) rearward from the rear end of the high-hardness area 21.
Preferably, a length L30 of a front portion 30 from a front end of the plate 3 to a front end of the high-hardness area 21 is greater than a length L31 of a rear portion 31 from a rear end of the plate 3 to a rear end of the high-hardness area 21.
In such a case, the impulse input from the short rear portion 31 during heel contact HC is accumulated in the long front portion 30. Therefore, the function of the plate 3 to function like a leaf spring is increased, and the energy absorption efficiency will be high.
Preferably, a hardness of a foam body (foamed material) forming the high-hardness area 21 is set to a value that is 5° to 20° greater than a hardness of a foam body (foamed material) forming the low-hardness area 20 in terms of the JIS-C hardness.
If the hardness difference is less than 5° in terms of the JIS-C hardness, the jump height will not improve sufficiently. On the other hand, if the hardness difference is greater than 20°, one may feel an upthrust due to the high-hardness area 21, or the hardness of the low-hardness area 20 will be too low.
Note that the hardness of the low-hardness area 20 is typically preferably about 50° to 60°. On the other hand, the hardness of the high-hardness area 21 is preferably about 60° to 75°, and most preferably about 65° to 70°.

EMBODIMENTS

The present invention will be understood more clearly from the following description of preferred embodiments taken in conjunction with the accompanying drawings. Note however that the embodiments and the drawings are merely illustrative and should not be taken to define the scope of the present invention. The scope of the present invention is defined only by the appended claims. In the accompanying drawings, like reference numerals denote like components throughout the plurality of figures.
One embodiment of the present invention will now be described with reference to FIG. 1 to FIG. 7 .
As shown in FIG. 1 to FIG. 5 , the shoe sole is a shoe sole suitable for an indoor sport such as handball, for example, and includes the outsole 1 having a tread surface to be in contact with the ground surface, the midsole 2 arranged on the outsole 1, and the plate 3.
The main body (majority) of the midsole 2 is made of a foam body (foamed material), it is for example formed by a material suitable for shock absorption such as a foam body containing a resin component such as EVA (ethylene-vinyl acetate copolymer). On the other hand, the outsole 1 is formed by a material having a good wear resistance such as a foam body or a non-foam body (non-foamed material) of a rubber, for example.
As shown in FIG. 2 , the midsole 2 includes the low-hardness area 20 and the high-hardness area 21. Note that in FIG. 1 to FIG. 5 , the high-hardness area 21 is shaded with fine dots, and the plate 3 is shaded with coarse dots.
The foamed material of the midsole 2 of FIG. 1 contains a thermoplastic resin component and another arbitrary suitable component. The thermoplastic resin component may be, for example, a thermoplastic elastomer and a thermoplastic resin. Note that a gel having a high shock-absorbing property may be embedded in the rearfoot portion 5R of the midsole 2, or a well-known reinforcement unit for reinforcing the middle foot portion 5M may be provided on the upper surface of the midsole 2.
An insole (not shown) is inserted on the midsole 2. A sockliner is inserted on the insole inside the upper.
The forefoot portion 5F, the middle foot portion 5M and the rearfoot portion 5R each mean an area covering the forefoot section, the middle foot section and the rearfoot section, respectively, of the foot of FIG. 3 .
As is well known in the art, the forefoot section includes five metatarsal bones and fourteen phalanges. The middle foot section includes a navicular bone, a cuboid bone, and three cuneiform bones. The rearfoot section includes a talus bone and a calcaneal bone BC.
As shown in FIG. 2 , the low-hardness area 20 is provided so as to extend continuously in an area of the majority of the forefoot portion 5F, the majority of the middle foot portion 5M and the majority of the rearfoot portion 5R. The hardness of the foamed material of the low-hardness area 20 is preferably an ordinary hardness of the midsole member, and is set to about 50° to 60° in terms of the JIS-C hardness, for example.
As shown in FIG. 1 , the high-hardness area 21 is arranged between the Chopart's joint JS and the rear end of the calcaneal bone BC, and preferably arranged between the front end of the calcaneal bone BC and the medial projection BC2 of the calcaneal tuberosity BC1. In this preferable embodiment, the low-hardness area 20 is at least arranged anterior to the front end of the calcaneal bone BC and posterior to the medial projection BC2.
The high-hardness area 21 of FIG. 2 is provided in a portion of the central portion 2C and/or a portion of the lateral portion 2L (of the medial portion 2M, the central portion 2C and the lateral portion 2L, which are defined by equally dividing the rearfoot portion 5R three ways along the transverse direction perpendicular to the longitudinal axis CL of the foot); in the present embodiment, it is provided only on the lateral side L of the longitudinal axis CL. Note that the low-hardness area 20 is provided right next to, on the medial side M of, the high-hardness area 21; therefore, the low-hardness area 20 has such a shape that it is partially cut out (notched) or holed by the high-hardness area 21, and the middle foot portion 5M and the rearfoot portion 5R are continuous with each other.
The foamed material of the high-hardness area 21 has a higher hardness than the foamed material forming the low-hardness area 20. The hardness of the foamed material forming the high-hardness area 21 is set to a value that is preferably 5° to 20°, more preferably about 10° to 15°, greater than the hardness of the foamed material forming the low-hardness area 20 in terms of the JIS-C hardness. For example, the hardness of the foamed material of the high-hardness area 21 is set to 65° to 70° in terms of the JIS-C hardness.
The average value W1 of the first width from the lateral end of the high-hardness area 21 to the opposite end thereof from the lateral end is set to 40% to 60% of the whole width W of the midsole 2 in the area where the high-hardness area 21 extends across. Note that the high-hardness area 21 does not need to extend at the right angle (directly horizontal) across the shoe, but may be inclined.
In FIG. 4 and FIG. 1 , the average value H1 of the first height of the high-hardness area 21 is set to 80% to 100% of the average value H of the height over the whole width of the midsole 2 in the area where the high-hardness area 21 is arranged.
As shown in FIG. 1 , the plate 3 is located between the upper surface of the outsole 1 and the upper surface of the midsole 2 and is continuous from the middle foot portion 5M to the rearfoot portion 5R. The plate 3 has a greater Young's modulus than Young's moduli of materials of the outsole 1 and the midsole 2.
The plate 3 is arranged between the upper surface of the outsole 1 and the lower surface of the midsole 2 in the present embodiment, but in a case where the midsole 2 is provided in the form of two, upper and lower, layers, for example, the plate 3 may be provided sandwiched between the upper and lower layers of the midsole 2.
As clearly shown in FIG. 3 , the front end of the plate 3 is arranged at a position posterior to the front end of the ball O1 of the big toe and anterior to the base of the metatarsal bone B14 of the big toe B1. The plate 3 is arranged continuously anterior to, directly below and posterior to the high-hardness area 21 of FIG. 1 . The rear end of the plate 3 is set at a position posterior to the medial projection BC2 of the calcaneal tuberosity BC1 (FIG. 1 ).
The length L30 of the front portion 30 from the front end of the plate 3 to the front end of the high-hardness area 21 is greater than the length L31 of the rear portion 31 from the rear end of the plate 3 to the rear end of the high-hardness area 21.
The width of the plate 3 of FIG. 3 is greater than the first width W1 of the high-hardness area 21 and is slightly smaller than the whole width W of the midsole 2. The width of the plate 3 is preferably about 60% to 95% of the width of the midsole 2. Note that where the width of the plate 3 is narrow, the plate 3 may be lopsided toward the lateral side of the midsole 2.
The average value of the flexural rigidity in dorsal flexion of the front portion 30 of the plate 3 anterior to the high-hardness area 21 is greater than that of the rear portion 31 of the plate 3 posterior to the high-hardness area 21.
Even if the average values are not in such a relationship with each other, the spring effect will be realized to some extent. While a cutout (notch) 32 at the rear end of the plate 3 may be absent (not be provided), the cutout 32 makes it easier to lower the rigidity of the rear portion 31 of the plate 3 and to lower the rigidity of the low-hardness area 20.
Ventilation holes may be provided in the plate 3.
Moreover, the rear end of the plate 3 may extend to a point posterior to the rear end of the foot, as in squash shoes, for example.
Next, the results of a test on the effect of the athletic shoe having the shoe sole of the present embodiment, for the one-foot jump shot in handball, will be described.
In this test, handball shoes according to the embodiment of FIG. 1 to FIG. 5 were used as Test Example, and handball shoes sold on the market were used as Comparative Example. Handball players performed multiple jump shots wearing these shoes, while the jump height at the top of the jump was measured, shown in FIG. 7A , and the distance jumped forward until reaching the top of the jump was measured, shown in FIG. 7B .
As can be seen in FIG. 7A , Test Example had a jump height greater than that of Comparative Example by about 15 mm (a few %). As can be seen in FIG. 7B , the distance jumped forward of Test Example was shorter than that of Comparative Example by about 100 mm (10%).
The impulse of the braking force from heel contact HC to foot flat FF (FIG. 6B and FIG. 6A ) during the jump shots was also measured, and the impulse for Test Example was higher than that for Comparative Example by about 10%. Moreover, the braking force at heel rise during the jump shot was also measured, and the braking force for Test Example was less than that for Comparative Example by about a few %.
The load at first strike when the impact is highest, i.e., at heel contact HC was also measured. As a result, the impact load for Test Example was smaller than that for Comparative Example by about 15%. Therefore, it can be seen that the structure of the present shoe sole is suitable not only for indoor sports, but also for running outdoors or walking as an exercise.
The effect of the shoe sole of the present invention was made clear from these test results.
Next, another embodiment will be described with reference to FIG. 8 .
In the present embodiment, the easy-to-compress area 20A is provided instead of the low-hardness area 20, while the hard-to-compress area 21A is provided instead of the high-hardness area 21.
The easy-to-compress area 20A of FIG. 8 is provided in an area of the majority of the middle foot portion 5M and the majority of the rearfoot portion 5R. On the other hand, the hard-to-compress area 21A is arranged in the same area as in the embodiment of FIG. 1 , and has a greater compressive rigidity than that of the material forming the easy-to-compress area 20A.
The plate 3 is arranged continuously from anterior to the hard-to-compress area 21A to posterior to the hard-to-compress area 21A, and the lower surface of the plate 3 is attached to the upper surface of the outsole 1 anterior to and posterior to the hard-to-compress area 21A.
In the present embodiment, the hard-to-compress area 21A may be provided in the form of a ridge (rib) of the plate 3, or one may employ a structure where the outsole 1 fills in a bent portion of the plate 3, for example.
Other than this, the configuration is similar to that of the embodiment of FIG. 1 to FIG. 5 , and will not be further described below.
Next, a variation of the high-hardness area 21 and/or the hard-to-compress area 21A in each embodiment will be described.
While the high-hardness area 21 of FIG. 4 has a levee-like shape that is generally a rectangular solid, the high-hardness area 21 may have a levee-like shape with a trapezoidal cross section as shown in FIG. 8 , or a levee-like shape with a triangular cross section as shown in FIG. 6B .
Although the high-hardness area 21 of FIG. 1 is provided over the entire height of the midsole 2 from the lower surface to the upper surface thereof, it may be provided over a part of the midsole 2 in the vertical (up-and-down) direction. Where the high-hardness area 21 is thus provided partially, the high-hardness area 21 may be provided in an upper portion, a lower portion or an intermediate portion in the vertical direction of the midsole 2.
The planar shape of the high-hardness area 21 of FIG. 2 does not need to be rectangular, but may be triangular, wave-shaped, trapezoidal, square, or a combination thereof.
For example, a plurality of square high-hardness portions may be arranged in the width direction of the foot while being spaced apart from one another, so that the high-hardness portions together form a single high-hardness area 21. In such a case, the width of the high-hardness area 21 should be considered as being the distance from the lateral end of the most lateral L high-hardness portion to the medial end of the most medial M high-hardness portion.
Where the high-hardness area 21 is triangular or trapezoidal, for example, the length of the high-hardness area 21 along the foot-length (longitudinal) direction may gradually decrease as the high-hardness area 21 extends from the lateral portion 2L toward the central portion 2C.
The high-hardness area 21 may be formed by a high-hardness portion surrounding a part or whole of the perimeter of a low-hardness portion.
Regarding the arrangement of the high-hardness area 21 in the transverse direction X, although a part of the high-hardness area 21 is provided in a roll-up portion 22 on the lateral side L of the midsole 2, the high-hardness area 21 may be absent (not provided) in the roll-up portion 22. The high-hardness area 21 may be provided only in the lateral portion 2L or the central portion 2C.
While preferred embodiments have been described above with reference to the drawings, various obvious changes and modifications will readily occur to those skilled in the art upon reading the present specification.
For example, an area where the hardness is higher than the low-hardness area 20 may be provided, on the medial side, in the middle foot portion 5M or the rearfoot portion 5R of the midsole 2, in order to suppress overpronation.
An area where the hardness is higher than the low-hardness area 20 may be provided in the roll-up portion 22 in the forefoot portion 5F or the middle foot portion 5M of the midsole 2 to suppress lateral shifting (falling (down) to lateral-side) of the foot.
The structure of the present invention may be applied only to a shoe for the pivot foot, or the structure of the present invention may be applied to both feet.
Thus, such changes and modifications are deemed to fall within the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is applicable not only to indoor shoes for handball, basketball, etc., but also to athletic shoes for running or walking outdoors.

REFERENCE SIGNS LIST

1: Outsole
2: Midsole, 2C: Central portion, 2L: Lateral portion, 2M: Medial portion, 22: Roll-up portion
20: Low-hardness area, 20A: Easy-to-compress area,
21: High-hardness area, 21A: Hard-to-compress area
3: Plate, 30: Front portion, 31: Rear portion
5F: Forefoot portion, 5M: Middle foot portion, 5R: Rearfoot portion
BC: Calcaneal bone, BC1: Calcaneal tuberosity, BC2: Medial projection
CL: Longitudinal axis
FF: Foot flat, HC: Heel contact
H: Average height value over whole width, H1: Average first height value
L: Lateral side, M: Medial side
O1: Ball of big toe
W: Whole width, W1: First width

Claims

A shoe sole of an athletic shoe, comprising:
an outsole 1 having a tread surface;

a mid sole 2 arranged above the outsole 1; and

a plate 3 located between an upper surface of the outsole 1 and an upper surface of the mid sole 2 and being continuous from a middle foot portion 5M to a rear foot portion 5R, the plate 3 being formed by a material having a greater Young's modulus than Young's moduli of materials of the outsole 1 and the mid sole 2, wherein:
the mid sole 2 includes:
a low-hardness area 20 provided in an area of a majority of the middle foot portion 5M and a majority of the rear foot portion 5R; and

a high-hardness area 21 arranged between a Chopart's joint JS and a rear end of a calcaneal bone BC, wherein where a medial side portion 2M, a central portion 2C and a lateral side portion 2L are obtained by dividing the rear foot portion 5R in three equal parts in a transverse direction X perpendicular to a longitudinal axis CL of a foot, the high-hardness area 21 is provided in at least a portion of the central portion 2C and/or at least a portion of the lateral side portion 2L;

a hardness of a foam body forming the high-hardness area 21 is greater than that of the low-hardness area 20; and

the plate 3 is arranged continuously anterior to, directly below, and posterior to, the high-hardness area 21.
The shoe sole according to claim 1, wherein:
the high-hardness area 21 is arranged between the Chopart's joint JS and a medial projection BC2 of a calcaneal tuberosity BC1; and

the low-hardness area 20 is arranged to at least extend anterior to the Chopart's joint JS and posterior to the medial projection BC2.
The shoe sole according to claim 1, wherein:
the high-hardness area 21 is arranged between a front end of the calcaneal bone BC and a rear end of the calcaneal bone BC; and

the low-hardness area 20 is arranged to at least extend anterior to the front end of the calcaneal bone BC and posterior to the rear end of the calcaneal bone BC.
The shoe sole according to claim 1, wherein:
the high-hardness area 21 is arranged between a front end of the calcaneal bone BC and a medial projection BC2 of a calcaneal tuberosity BC1; and

the low-hardness area 20 is arranged to at least extend anterior to the front end of the calcaneal bone BC and posterior to the medial projection BC2.
The shoe sole according to any one of claims 1 to 4, wherein:
an average value W1 of a first width from a lateral end of the high-hardness area 21 to an opposite end thereof from the lateral end is set to 17% to 100% of a whole width W of the midsole 2 in an area where the high-hardness area 21 extends across.
The shoe sole according to any one of claims 1 to 5, wherein:
an average value H1 of a first height of the high-hardness area 21 is set to 25% to 150% of an average value H of a height over a whole width W of the midsole 2 in an area where the high-hardness area 21 is arranged.
The shoe sole according to any one of claims 1 to 6, wherein:
an average value of a flexural rigidity in dorsal flexion, of a front portion 30 of the plate 3 which is anterior to the high-hardness area 21 is greater than that of a rear portion 31 of the plate 3 which is posterior to the high-hardness area 21.
The shoe sole according to any one of claims 1 to 7, wherein:
a width of the plate 3 is greater than a width of the high-hardness area 21.
The shoe sole according to any one of claims 1 to 8, wherein:
a front end of the plate 3 is arranged posterior to a front end of a ball O1 of a big toe.
The shoe sole according to any one of claims 1 to 8, wherein:
a front end of the plate 3 is set at a position posterior to a front end of a ball O1 of a big toe and anterior to a base of a metatarsal bone B14 of the big toe B1.
The shoe sole according to any one of claims 1 to 10, wherein:
a rear end of the plate 3 is set at a position posterior to a medial projection BC2 of a calcaneal tuberosity BC1.
The shoe sole according to any one of claims 1 to 11, wherein:
a length L30 of a front portion 30 from a front end of the plate 3 to a front end of the high-hardness area 21 is greater than a length L31 of a rear portion 31 from a rear end of the plate 3 to a rear end of the high-hardness area 21.
The shoe sole according to any one of claims 1 to 12, wherein:
a hardness of a foam body forming the high-hardness area 21 is set to a value that is 5° to 20° greater than a hardness of a foam body forming the low-hardness area 20 in terms of the JIS-C hardness.
The shoe sole according to any one of claims 1 to 13, wherein:
the low-hardness area 20 is arranged anterior to a front end of, and posterior to a rear end of, the high-hardness area 21.
A shoe sole of an athletic shoe, comprising:
an outsole 1 having a tread surface;

a mid sole 2 arranged above the outsole 1; and

a plate 3 located between an upper surface of the outsole 1 and an upper surface of the mid sole 2 and being continuous from a middle foot portion 5M to a rear foot portion 5R, the plate 3 having a greater Young's modulus than Young's moduli of the outsole 1 and the mid sole 2, wherein:
the mid sole 2 includes:
an easy-to-compress area 20A provided in an area of a majority of the middle foot portion 5M and a majority of the rear foot portion 5R; and

a hard-to-compress area 21A arranged between a Chopart's joint JS and a rear end of a calcaneal bone BC, wherein where a medial side portion 2M, a central portion 2C and a lateral side portion 2L are obtained by dividing the rear foot portion 5R in three equal parts in a transverse direction X perpendicular to a longitudinal axis CL of a foot, the hard-to-compress area 21A is provided in at least a portion of the central portion 2C and/or at least a portion of the lateral side portion 2L, the hard-to-compress area 21A having a greater compressive rigidity than a material forming the easy-to-compress area 20A; and

the plate 3 is arranged continuously anterior to, directly below, and posterior to, the hard-to-compress area 21A, and a lower surface of the plate 3 is attached to an upper surface of the outsole 1 anterior to and posterior to the hard-to-compress area 21A.