Patent Application
20100071231
This invention relates generally to a stabilizing element for a shoe, and a shoe containing said stabilizing device and, more specifically, to a stabilizing device for controlling the rolling motion of a wearer's foot over a foot strike path.
The complex motions of the foot that can occur during a gait cycle of a wearer have been the focus of a multitude of biomechanical studies with a goal toward injury prevention and generally improved walking and running performance shoes. In particular, it has been an objective in the design of modern athletic shoes to provide support and cushioning where needed over a typical gait cycle. Typically, cushioning is provided in areas of a midsole of a shoe under the heel region to help minimize the impact of initial heel strike. Additional support elements are also typically provided to reduce excessive rolling of the foot toward the inner (medial) side or outer (lateral) side during a gait cycle by appropriate positioning of stiffening materials and structures.
The tendency to roll toward the medial side after initial heel impact, or pronation, is a normal movement of the foot that occurs during walking or running. Immediately following the initial heel strike, the joint between the foot bones called the subtalar joint is unlocked, allowing pronation, a coordinated triplane motion of the foot, to occur during the forefoot lowering events of the loading period of the so-called stance phase. The triplane motions are: (1) abduction, in which the front of the foot is turned outwards at the subtalar joint and away from the line of progression of the wearer; (2) dorsiflexion, in which the front of the foot is angled upwards relative to the heel of the foot at the ankle, or talocrural joint; and (3) eversion, in which the sole of the foot is turned outward relative to the heel of the foot at the subtalar joint. With this coordinated combination of three planes of motions, the foot typically rolls from the lateral side toward the medial side of the foot as the medial aspect of the midfoot area of the foot comes into contact with the running surface. This triplane rolling of the foot as the wearer's body weight begins to move forward allows the foot to transfer some of the loading force to the waling or running surface. The foot remains in a pronated position throughout the mid-stance phase.
Supination typically follows pronation. As one's body weight moves forward over the foot, the subtalar joint locks and a reversal of the events that occurred during the loading period occurs. Supination involves the motions of: (1) adduction, in which the locking of the subtalar joint allows the foot to turn inward toward the line of progression; (2) plantarflex, in which the forefoot is flexed downward relative to the heel at the ankle; and (3) inversion, in which the sole of the foot is turned inward at the subtalar joint relative to the heel. With the combination of these three motions, the foot continues rolling forward onto the toes. During motion through ball and toe contact, the foot rolls outward just before the toes start to leave the ground. The combination of these motions allows the foot to be converted from a mobile adaptor to a rigid lever, which is essential for the forward propulsion of the body.
Though pronation and supination are natural motions, both excessive pronation, often caused by high pronation velocity, and excessive supination are undesirable and can lead to injury. Various approaches have been used in footwear design to control these rotational motions to avoid injury. Traditional so-called medial “post” or “posting” systems typically use a firmer density of ethylene vinyl acetate (“EVA”) or polyurethane (“PU”) foam on the medial side of a shoe in a rearfoot portion of a midsole to control pronation. However, it is difficult to control the density and hardness of such foams. For example, manufactured foams are often softer than specified in production. In addition, it takes more time and costs more to make the denser EVA foams. Such medial posts often use two densities of foam in a wedged configuration to provide a smoother transition for the foot as it rolls from heel to toe. However, both the relative density and thickness of these foams are difficult to control during manufacturing, and the positioning of a wedge of rigid foam over a softer foam does not provide a truly continuous transition of stiffness from heel strike to toe-off.
Prior devices address motion control primarily by altering compression resistance underneath the foot using discrete rigid posts and plates or dual density midsole foams. The prior devices provide little or no transition of compression resistance. In addition, such transition is offered only under the foot and in only one direction—transverse to the longitudinal axis of the shoe. None of the prior devices discloses or suggests a device for precisely and smoothly controlling the motion of the foot along a foot strike path or providing a continuous transition in compression resistance as the foot traverses a strike path.
Accordingly, there is a need, which has not been adequately addressed in the prior art, for a device for precisely and smoothly controlling the motion of a foot along a foot strike path and that also provides a continuous and smooth transition in compression resistance along the foot strike path.
A stabilizing device of the present invention addresses the deficiencies of the prior art by precisely and smoothly controlling the motion of the foot along a foot strike path by providing a continuous variation in stiffness along a medial or lateral side of a wearer's foot. A shoe sole and a shoe which include the stabilizing device are also formed in accordance with the present invention.
In one embodiment, a stabilizing device for use in a shoe sole has a first end and a second end. The first end is adapted to be mounted in the rearfoot region of the shoe and the second end is adapted to be mounted in the arch region of the shoe. The stabilizing device has an elongated portion positioned between the first end and the second end that will extend along a periphery of a shoe sole from the rearfoot region into the arch region. The stabilizing device also has a sidewall portion that extends from the rearfoot region into the arch region. The sidewall portion extends transversely from the elongated portion along the length of the elongated portion. The sidewall portion is adapted for forming a portion of a peripheral wall on either the medial or lateral side of the shoe. The sidewall portion has a stiffness that varies continuously from the first end toward the second end.
In one embodiment, the stiffness of the sidewall portion decreases continuously from the first end toward the second end. In another embodiment, the stiffness of the sidewall portion increases continuously from the first end toward the second end.
In another embodiment the cross-sectional area formed from the sidewall portion and the elongated portion varies continuously from the first end toward the second end. In accordance with this embodiment, the cross-sectional area can also decrease continuously from the first end toward the second end. In another embodiment, the cross-sectional area increases continuously from the first end toward the second end.
In a further embodiment, a stiffness of the elongated portion varies continuously from the first end toward the second end. In accordance with this embodiment, the stiffness of the elongated portion can also decrease continuously from the first end toward the second end. In another embodiment, the stiffness of the elongated portion increases continuously from the first end toward the second end.
In still another embodiment, the stabilizing device is adapted to extend from either the medial or lateral side of the shoe across 20% to 35% of the width of the shoe at the arch region.
In one embodiment, the elongated portion has a surface adapted for being positioned flush with an upper surface of the shoe sole.
In another embodiment, the sidewall portion has a lower portion that is adapted to extend from the elongated portion towards a ground engaging surface of the shoe. In accordance with this embodiment, a lower extension portion can also extend transversely from an end of the lower portion of the sidewall portion away from the elongated portion.
The stabilizing device of the above embodiments may be integrally formed of a thermoplastic material. The thermoplastic material may be injection molded thermoplastic.
In one embodiment, the stabilizing device of any of the above embodiments is adapted to be positioned along the medial side of the shoe. In another embodiment, the stabilizing device is adapted to be positioned along the lateral side of the shoe.
The stabilizing device may further include an extended heel portion. The extended heel portion includes an extended elongated portion. The extended elongated portion is integrally connected to the elongated portion of the stabilizing device. The extended heel portion also includes an extended sidewall portion. The extended sidewall portion is integrally connected to the sidewall portion of the stabilizing device. The extended sidewall portion has a stiffness that varies continuously. The extended heel portion is adapted to extend from one the medial or later side of the shoe, around the heel end of the shoe, to the other of the medial or lateral side of the shoe.
In one embodiment, the stiffness of at least one of the extended sidewall portion and the extended elongated portion increases continuously along the medial and lateral sides toward the rear of the extended heel portion. In another embodiment, the stiffness of at least one of the extended sidewall portion and the extended elongated portion decreases continuously along the medial and lateral sides toward the rear of the extended heel portion.
A shoe formed in accordance with the present invention includes a stabilizing device. The shoe has an upper and a shoe sole. The stabilizing device is disposed along either the medial or lateral side of the shoe sole. The stabilizing device has a first end and a second end. The first end is mounted in the rearfoot region of the shoe and the second end is mounted in the arch region of the shoe. The stabilizing device has an elongated portion positioned between the first end and the second end that extends along a periphery of the shoe sole from the rearfoot region into the arch region. The stabilizing device also has a sidewall portion that extends from the rearfoot region into the arch region. The sidewall portion extends transversely from the elongated portion. The sidewall portion forms a portion of a peripheral wall on either the medial or lateral side of the shoe. The sidewall portion has a stiffness that varies continuously from the first end toward the second end.
In one embodiment, the stiffness of the sidewall portion decreases continuously from the first end toward the second end. In another embodiment, the stiffness of the sidewall portion increases continuously from the first end toward the second end.
In another embodiment the cross-sectional area formed from the sidewall portion and the elongated portion varies continuously from the first end toward the second end. In accordance with this embodiment, the cross-sectional area can decrease continuously from the first end to the second end. In another embodiment, the cross-section area increases continuously from the first end to the second end.
In a further embodiment, a stiffness of the elongated portion varies continuously from the first end toward the second end. In accordance with this embodiment, the stiffness of the elongated portion can decrease continuously from the first end toward the second end. In another embodiment, the stiffness of the elongated portion increases continuously from the first end toward the second end.
In still another embodiment, the stabilizing device extends from either the medial or lateral side of the shoe across 20% to 35% of the width of the shoe at the arch region.
In one embodiment, the elongated portion has a surface positioned flush with an upper surface of the shoe sole.
In another embodiment, the sidewall portion has a lower portion that extends from the elongated portion towards a ground engaging surface of the shoe. In accordance with this embodiment, a lower extension portion can also extend transversely towards the center of the shoe sole from an end of the lower portion away from the elongated portion.
The stabilizing device of the above embodiments can be integrally formed of a thermoplastic material. The thermoplastic material can be injection molded thermoplastic.
In one embodiment, the stabilizing device is positioned along the medial side of the shoe. In another embodiment, the stabilizing device is positioned along the lateral side of the shoe.
The stabilizing device may further include an extended heel portion. The extended heel portion includes an extended elongated portion. The extended elongated portion is integrally connected to the elongated portion of the stabilizing device. The extended heel portion also includes an extended sidewall portion. The extended sidewall portion is integrally connected to the sidewall portion of the stabilizing device. The extended sidewall portion has a stiffness that varies continuously. The extended heel portion extends from one the medial or later side of the shoe, around the heel end of the shoe, to the other of the medial or lateral side of the shoe.
In one embodiment, the stiffness of at least one of the extended sidewall portion and the extended elongated portion increases continuously along the medial and lateral sides toward the rear of the extended heel portion. In another embodiment, the stiffness of at least one of the extended sidewall portion and the extended elongated portion decreases continuously along the medial and lateral sides toward the rear of the extended heel portion.
When positioned on a medial side of the shoe, the stabilizing device reduces pronation velocity of the subtalar joint by providing a precisely controlled stiffness that continuously decreases from the rearfoot region to the arch region along the longitudinal axis and on the medial side of the shoe. When positioned on a lateral side of the shoe, the stabilizing device reduces supination velocity of the subtalar joint by providing a precisely controlled stiffness that continuously decreases from the rearfoot region to the arch region along the longitudinal axis on the lateral side of the shoe.
Referring to
The stabilizing device 201 also includes a sidewall portion 205 that extends transversely from the elongated portion 204 along the length of the elongated portion 204 and preferably beyond. The sidewall portion 205 is adapted to form a portion of an outer peripheral wall on either the medial or lateral side of the shoe in which it is positioned. The sidewall portion 205 has a stiffness that varies continuously from the first end 202 toward the second end 203. In one embodiment, the stiffness of the sidewall portion 205 decreases continuously from the first end 202 toward the second end 203. In another embodiment, the stiffness of the sidewall portion 205 increases continuously from the first end 202 toward the second end 203.
The elongated portion 204 is adapted for mounting no further forward than the arch region of the shoe. By restricting the elongated portion 204 of the stabilizing device 201 to the arch and heel region, the phalanges 102 of the foot 100 are allowed to flex while the wearer is walking or running, which assists in pushoff and enables more efficient movement.
In addition to varying the stiffness of the sidewall portion 205, the stiffness of the elongated portion 204 can also be varied continuously from the first end 202 toward the second end 203. In one embodiment, the stiffness of the elongated portion 204 decreases continuously from the first end 202 toward the second end 203. In another embodiment, the stiffness of the elongated portion 204 increases continuously from the first end 202 toward the second end 203.
In order to control the stiffness of the sidewall portion 205 and/or the elongated portion 204, the cross-sectional area formed from the sidewall portion 205 and the elongated portion 204 can be varied continuously from the first end 202 toward the second end 203. In one embodiment, this cross-sectional area decreases continuously from the first end 202 toward the second end 202. In another embodiment, this cross-section area increases continuously from the first end 202 toward the second end 203.
In another embodiment, the sidewall portion 205 has a lower portion 207 that is adapted to extend from the elongated portion 204 towards a ground engaging surface of the shoe. In yet another embodiment, as best shown in
The stabilizing device 201 is adapted to be positioned along the medial side of the shoe or along the lateral side of the shoe. Referring to
In one embodiment, the lower portion 207 of the sidewall portion 205 extends from the elongated portion 204 towards a ground engaging surface 210 of the shoe sole 200. A lower extension portion 208 extends transversely from the lower portion 207. The lower extension portion 208 can be mounted between two layers of the shoe sole 200, for example, ground engaging surface 209 and midsole 210, as shown in
In one embodiment, shown in
The elongated portion 204 of the stabilizing device 201 extends along a periphery of the shoe 200 and extends from either the medial side or the lateral side of the shoe toward, but not past, the longitudinal centerline of the shoe. In other embodiments, the stabilizing device 201 also extends along the peripheral rear of the shoe, encompassing the heel (
One end 202 of the elongated portion 204 is positioned in the rearfoot region of the shoe 200. In one embodiment, the first end 202 is adapted to be positioned in a portion of the sole situated below the talus bone of the wearer's foot. In another embodiment, the first end 202 is located a distance from the rear end 216 of the shoe 200 that is between about 5% and 35% of the length of the shoe. Most preferably the distance is between about 10% and 20%. In another embodiment, the distance is between about 12% and 18%.
The second end 203 is positioned in the arch region of the shoe 200. For a stabilizing device 201 located on a medial side of the shoe 200, the second end 203 is preferably located a distance from the rear end 216 of the shoe 200 that is between about 50% and 80% of the length of the shoe. Most preferably, the distance is between about 60% to 75% of the length of the shoe. For a stabilizing device 201 located on the lateral side of the shoe 200, the second end 203 is preferably located a distance from the rear end 216 of the shoe that is between about 50% and 80% of the length of the shoe 200. Most preferably the distance is between about 60% to 75% of the length of the shoe 200.
As compared with the stabilizing device 201 shown in
In one embodiment, the stiffness of the extended sidewall portion 215 or the extended elongated portion 214, or both increases continuously along the medial and lateral sides toward the rear of the extended heel portion 213. In another embodiment, the stiffness of the extended sidewall portion 215, the extended elongated portion 214, or both decreases continuously along the medial and lateral sides toward the rear 216 of the extended heel portion 213.
As can be seen most clearly in
The stiffness of the stabilizing devices of the present invention can be directionally varied as needed by changing the thickness of the thermoplastic material. Accordingly, forces created on the shoe by a wearer's foot striking the ground will impact on different thicknesses in various directions along the foot strike path. Regions of thicker material will have a higher stiffness and are positioned where greater resistance is needed compared to thinner regions. In this way, the stabilizing device can be precisely shaped and formed to provide a continuous stiffness profile along a side of a shoe to control the motion of a wearer's foot along a foot strike path and a smooth transition in resistance as the foot rolls from its lateral side on heel strike toward the medial side prior to toe-off.
It is also contemplated that the density of the thermoplastic material itself can be varied to control the stiffness of the stabilizing device of the present invention. One skilled in the art will appreciate that a combination of density and thickness can also be precisely varied to form a stabilizing device having the desired continuous stiffness profile. Accordingly, the stabilizing device of this invention can be formed with any stiffness profile to provide a continuously varying stiffness in any direction to control the motion of a wearer's foot along a predetermined foot strike path.
Though in the embodiments shown, the stabilizing device is positioned in a midsole of the shoe, it is understood that the device can be adapted for mounting in any part or parts of a sole of a shoe, which may include an insole, an outsole, a midsole, or any combination of the foregoing. Generally, the stabilizing device is adapted for positioning anywhere below a plane of a wearer's foot with a sidewall extending above the sole and along the side of a wearer's foot. The sidewall preferably extends along a portion of an upper of the shoe.
Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention and claims are not limited to those precise embodiments, and that various other changes and modifications may be applied therein by one skilled in the art without departing from the scope or spirit of the invention. As will also be apparent to those skilled in the art, various combinations of the embodiments and features taught in the foregoing description are possible and can result in preferred executions of the present invention. Accordingly, it is intended that such changes and modifications fall within the scope of the present invention as defined by the claims appended hereto.
This application claims priority to U.S. provisional patent application Ser. No. 61/133,282, filed Jun. 26, 2008, the entirety of which is incorporated herein by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| 61133282 | Jun 2008 | US |
