FOOTWEAR SUPPORT SYSTEM

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 63/642,568, filed May 3, 2024, the disclosure of which is incorporated herein by reference in its entirety.

FIELD

The field is related to support systems for footwear.

BACKGROUND

Ankle sprains resulting from foot inversion are among the most common types of ankle sprains. People commonly use footwear with ankle support to resist ankle inversions and reduce the chances of an ankle sprain.

SUMMARY

According to some embodiments, an article of footwear is provided. The footwear may include a strap having a lateral strap portion connected to a lateral forefoot region of the footwear and a medial strap portion connected to a medial hindfoot region of the footwear. The footwear may also include a heel counter configured to be positioned adjacent to a user's heel when worn and the heel counter may be stiffer than an adjacent portion of an upper of the footwear. The heel counter may be configured to support the medial strap portion and the strap may be configured to apply a foot inversion resisting tension to a user's foot when the footwear is worn by the user.

According to some embodiments, a method of resisting foot inversion is provided. The method may include connecting a lateral strap portion connected to a lateral forefoot region of a footwear with a medial strap portion connected to a medial hindfoot region of the footwear. The method may also include positioning a heel counter adjacent to a user's heel when the footwear is worn by the user. In some embodiments, the heel counter may be stiffer than an adjacent portion of an upper of the footwear. The method may further include supporting the medial strap portion with the heel counter and applying a foot inversion resisting tension to the user's foot with the strap.

It should be appreciated that the foregoing concepts, and additional concepts discussed below, may be arranged in any suitable combination, as the present disclosure is not limited in this respect. Further, other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments when considered in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

FIG. 1 shows a top view of footwear according to an embodiment;

FIG. 2 shows a lateral side view of the footwear of FIG. 1;

FIG. 3 shows a medial side view of the footwear of FIG. 1; and

FIG. 4 shows an article of footwear having a sole plate, according to an embodiment.

DETAILED DESCRIPTION

Lateral ankle sprains often result from ankle inversions, where a person's foot rolls towards their body. When a person rolls their ankle, their body exerts a lateral torque on their ankle, potentially injuring ligaments in their ankle. The ankle is at a particularly high risk when the foot is plantar flexed and the forefoot region of the foot comes into contact with the ground or some other support surface, such as when stepping out of a vehicle or walking on uneven terrain. This type of sprain is often associated with the term “rolling the ankle”.

Conventional footwear attempting to offer ankle support to resist the likelihood and/or severity of ankle inversions generally provides such support in the hindfoot region of the footwear, such as with heel counters. Such heel counters are generally configured to cup the heel in the hindfoot region to secure the heel of the footwear to the user's foot through the use of shoe laces or hook and loop straps, and to support the hind foot to reduce the likelihood of and/or severity of injury from ankle inversion. However, conventional footwear does not provide adequate support to the lateral forefoot region to adequately resist lateral ankle sprain torque. Ankle sprains often result from ankle inversions originating from the lateral forefoot region, especially when the foot is in a plantar flexed position, so it may be desirable to add additional support to the lateral forefoot region.

The inventor has therefore recognized an advantage to providing a connected force path between the lateral forefoot region and the medial hindfoot region. Such a configuration may allow ankle support in the hindfoot region (e.g. heel counters) to exert an inversion resisting tension to the lateral forefoot region to resist ankle inversion in the lateral forefoot region. However, footwear is generally split by a tongue, and medial and lateral sides of the footwear are connected by conventional fasteners such as lace and eyelets, or other conventional fasteners, which do not adequately transmit force along the connected force path to resisting ankle inversion. The inventor has therefore recognized an advantage to connecting the lateral forefoot region of footwear with the medial hindfoot region of footwear with a strap to create the connected force path between these regions, and supporting the strap along the medial hindfoot region with a heel counter. As the lateral forefoot region of the foot begins to invert during an ankle inversion, the heel counter resists the inversion in the hindfoot region, and applies an inversion resisting tension to the lateral forefoot region through the strap to reduce the lateral torque the lateral forefoot region experiences. Such a configuration allows the heel counter in the hindfoot region of the footwear to provide support to the lateral forefoot to resist/limit injury from forefoot ankle inversions.

In some embodiments, the inventor has recognized an advantage to incorporating the strap into a closure system of the footwear. Such a configuration may allow for customization of the amount of tension the strap applies to the lateral forefoot region by adjusting the closure system. Such a configuration may also eliminate the need for an additional fastener system to secure the strap in place, reducing the number of steps a user must take to fully secure the footwear onto their foot. In some embodiments, the strap is divided into a lateral portion, which connects to the lateral forefoot region, and a medial portion, which connects to the medial hindfoot region. The lateral strap portion and medial strap portion may be connected to each other via the closure system. The closure system may be any suitable closure system (e.g. laces, touch fasteners, etc.).

In some embodiments, the closure system may be arranged asymmetrically such that the closure system is approximately aligned with a dorsal portion of the force path extending in an axial direction between the lateral strap portion and medial strap portion. Such a configuration may allow for the connected force path to be relatively continuous between the strap portions. In some embodiments, the closure system is between 0° and 20° offset from the dorsal portion of the force path. For instance, in some embodiments, a lacing system may be used as the closure system. The medial strap portion and lateral strap portion may include eyelets for the laces to thread through. When the laces are tightened, the strap portions are pulled together, applying inversion resisting tension to the lateral forefoot region. In some embodiments, at least some eyelets are arranged asymmetrically, such that a lateral eyelet is disposed anterior to a corresponding medial eyelet. Such a configuration may result in an asymmetrical lacing pattern, with at least some lace portions extending approximately parallel to the dorsal portion of the force path. Such a configuration may allow for the strap portions to extend along the optimal force path even when the lacing system is tightened and may allow for the lacing system to transfer the tension between the strap portions along the connected force path, resulting in more inversion resisting tension being applied to the lateral forefoot region.

In some embodiments, the strap may have a thickness, the thickness direction being transverse to a length of the strap and parallel to an underlying portion of a footwear upper of the footwear. The strap may be any suitable thickness which allows for effective transfer of the inversion resisting tension form the medial hindfoot region to the lateral forefoot region. In some embodiments, the strap may be of a thickness greater than or equal to 0.3 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or greater. In some embodiments, the strap may be of a thickness lesser than or equal to 6 mm, 5.5 mm, 5 mm, 4.5 mm, 4 mm, 3.5 mm, 3 mm, 2.5 mm, 2 mm, 1.5 mm, 1 mm, or lesser. Combinations of the foregoing are also contemplated. For example, the strap may be of a thickness between 1 mm and 5 mm, between 2 mm and 4 mm, between 2.5 mm and 3.5 mm, or any other suitable thickness range as the disclosure is not so limited. In some embodiments, the thickness of the strap may vary along a length of the strap according to any suitable thickness values disclosed herein.

In some embodiments, the strap may have a larger axial stiffness than adjacent portions of the footwear to allow for more effective transmission of the inversion resisting tension along the connected force path. In some embodiments, this axial stiffness may be greater than or equal to 50 N/mm, 100 N/mm, 150 N/mm, 200 N/mm, 250 N/mm, 300 N/mm, 350 N/mm, 400 N/mm, 450 N/mm, 500 N/mm, 550 N/mm, 600 N/mm, 650 N/mm, 700 N/mm, 750 N/mm, 800 N/mm, 850 N/mm, 900 N/mm or greater. In some embodiments, the axial stiffness of the strap may be less than or equal to 1,000 N/mm, 950 N/mm, 900 N/mm, 850 N/mm, 800 N/mm, 750 N/mm, 700 N/mm, 650 N/mm, 600 N/mm, 550 N/mm, 500 N/mm, 450 N/mm, 400 N/mm, 350 N/mm, 300 N/mm, 250 N/mm, 200 N/mm, or lesser. Combinations of the foregoing are also contemplated. For example, the strap may be of an axial stiffness between 200 N/mm and 900 N/mm, between 400 N/mm and 700 N/mm, between 500 N/mm and 600 N/mm, or any other suitable axial stiffness range as the disclosure is not so limited. In some embodiments, the axial thickness of the strap may vary along a length of the strap according to any suitable axial stiffness values disclosed herein.

In some embodiments, the strap may have a tensile strength greater than adjacent portions of the footwear. In some embodiments, the tensile strength of the strap may be greater than or equal to 250 N, 500 N, 750 N, 1,000 N, 1,250 N, 1,500 N, or greater at yield point. In some embodiments, the tensile strength of the strap may be less than or equal to 2,000 N, 1,750 N, 1,500 N, 1,250 N, 1,000 N, 750 N, 500 N, or lesser at yield point. Combinations of the foregoing are also contemplated. For example, the strap may have a tensile strength at yield point between 500 and 1,750 N, between 750 N and 1,500 N, between 1,000 N and 1,250 N, or any other suitable tensile strength range as the disclosure is not so limited. In some embodiments, the tensile strength at yield point of the strap may vary along the length of the strap according to any suitable tensile strength values disclosed herein.

In some embodiments, the strap may anchor to the lateral forefoot region at a location of the footwear approximately aligned with a user's 5^th Metatarsophalangeal joint (MTP joint), when the footwear is worn by the user. In some embodiments, the strap may anchor to the lateral forefoot region at a first location on the footwear aligned with or posterior to the user 5^th MTP joint when the footwear is worn, and at a second location anterior to the user's 5^th MTP joint when the footwear is worn by the user. In some embodiments, the first location may be at a distance from the user's 5^th MTP joint when the footwear is worn by the user of greater than or equal to 0 mm (i.e., the first location may be located at the user's 5^th MTP joint), 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50mm, 55 mm, 60 mm, 65 mm, 70 mm, or greater. In some embodiments, the first location may be at a distance from the user's 5^th MTP joint of lesser than or equal to 80 mm, 75 mm, 70 mm, 65 mm, 60 mm, 55 mm, 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, or lesser. In some embodiments, the second location may be at a distance from the user's 5^th MTP joint when the footwear is worn by the user of greater than or equal to 0 mm (i.e., the second location may be located at the user's 5^th MTP joint), 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, or greater. In some embodiments, the second location may be at a distance from the user's 5^th MTP joint of lesser than or equal to 50 mm, 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, or lesser. Combinations of the foregoing are also contemplated. For example, the first location may be at a distance of 30 mm from the user's 5^th MTP joint while the second location may be at a distance of 10 mm from the user's MTP joint when the footwear is worn by the user. While such an example is disclosed, any suitable combination of the above first and second location values may be used as the disclosure is not so limited.

In some embodiments, the inventor has recognized that the strap provides a more effective inversion resisting tension when tension is applied through the strap along a force path resulting from the strap being disposed relatively high on the medial hindfoot region. The inventor has therefore recognized an advantage to extending at least a portion of the strap along a relatively high section of the medial hindfoot region and supporting the strap with the heel counter. Such a configuration may allow for the inversion resisting tension to be applied to the lateral forefoot region along an optimal force path. In some embodiments, the strap extends along and is supported by the heel counter at a section of the medial hindfoot region approximately aligned with a portion of the user's talus when the footwear is worn by the user. In some embodiments, the strap extends along and is supported by the heel counter at a section of the medial hindfoot region directly below the axis of rotation of the user's ankle when the footwear is worn by the user. Such a configuration may allow for a relatively high amount of inversion resisting tension applied through the strap while providing minimal interference with the rotation of the user's ankle during ambulation. In some embodiments, the strap extends along and is supported by the heel counter at a section of the medial hindfoot region at a suitable distance below the axis of rotation of the user's ankle. In some such embodiments, a suitable distance below the axis of rotation of the user's ankle may be greater than or equal to 0 mm (i.e., the strap is supported by the heeler counter at a section of the medial hindfoot region located at the axis of rotation), 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, or greater. Likewise, in some embodiments, a suitable distance below the axis of rotation of the user's ankle may be lesser than or equal to 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, or lesser. In some embodiments, the strap extends along and is supported by the heel counter along a section of the medial hindfoot region anterior to the axis of rotation of the user's ankle. In some embodiments, the heel counter may be enlarged (e.g. extends further anteriorly and/or extends further upward) as compared to conventional heel counters to allow for the heel counter to support the strap along the sections of the medial hindfoot region to resist tension in the strap from deforming of the medial hindfoot region and allowing laxity in the strap. This support of the medial hindfoot region could also be provided in various other fashions, including the use of stiffeners, use of additional layers of upper material, or any other suitable fashion for resisting slump and buckling of the medial hindfoot region when the strap exerts tensile force in its generally forward and down direction as the disclosure is not so limited.

As noted above, a strap used to form a force transmission path within a footwear may exhibit an increased stiffness as compared to an adjacent portion of the footwear upper (e.g., the upper flexible portion of the footwear attached to a sole or other base of the footwear). For example, an axial stiffness of the strap may be greater in at least an axial direction extending along a length of the strap relative to an adjacent portion of the footwear. This may help to facilitate the transmission of the desired forces between the intended locations through the strap. Appropriate materials for the disclosed straps may include but are not limited to: webbing, leather, polyurethanes, vinyls, textiles, or any other suitable material as the disclosure is not so limited. Additionally, an appropriate stiffness for a strap may be greater than or equal to 1 N/mm, 3 N/mm, 5 N/mm, 7 N/mm, 10 N/mm, 12.5 N/mm, 15 N/mm, 17.5 N/mm, or greater. In some embodiments, an appropriate stiffness for a strap may be lesser than or equal to 20 N/mm, 17.5 N/mm, 15 N/mm, 12.5 N/mm, 10 N/mm, 7.5 N/mm, 5 N/mm, or lesser.

In some embodiments, the inventor has recognized an advantage forming heel counter from a stiff material, such that the heel counter is stiffer than adjacent portions of footwear. Such a configuration may prevent buckling of the heel counter, allowing a greater amount of tension to be applied, and also maintaining application of the tension along the optimal force path. The stiff heel counter may be constructed out of any suitable material using any suitable process. For instance, the heel counter may be constructed of a three dimensional printed, molded, or other appropriately formed material such as carbon fiber, nylon, thermoplastic polyurethane (TPU), polyurethane (PU), other appropriate polymers, resin-stiffened textiles, leathers, metals, combinations of the forgoing, and/or any other appropriate material.

In some embodiments, the inventor has recognized that it may be desirable to incorporate an exoskeleton into the footwear configured to apply a plantar flexion assisting torque to the user's foot during some portions of the user's gait cycle. For example, in some embodiments, an exotendon spring may be provided which returns energy in the initial portion of the propulsive phase following heel lift. Heel lift may be associated with maximum dorsiflexion, which may range from 10 to 45 degrees of dorsiflexion according to the user and the activity. The end of the initial portion of the propulsive phase may be considered when the foot is within 2 degrees dorsiflexion to 2 degrees plantar flexion, otherwise known as neutral position.

In some embodiments, the heel counter may be a base of the exoskeleton, and the exoskeleton may also include a yoke. The yoke may be attached to the base via lateral and medial rotatable connections, with an axis of rotation of the rotatable connections approximately aligned with the axis of rotation of the user's ankle in the sagittal plane when the footwear is worn by the user. The yoke may span between medial and lateral sides of the footwear, and be configured to contact a front of the user's leg above the user's ankle and below the user's knee. As a user dorsiflexes their foot while ambulating, their leg rotates relative to their foot in a first direction, and contact between the front of the leg and the yoke causes the yoke to rotate in the first direction. In some embodiments, at least one spring may extend between the yoke and the base and is configured to deform as the yoke rotates relative to the base in the first direction. As a user plantar flexes, their leg rotates in a second direction opposite to the first direction. The at least one spring may then return to an original configuration and apply a plantar flexion assisting torque to the user's foot during the user's gait.

In some embodiments, the presence of an exosekeleton can further augment the vertical height of footwear, creating additional surface area on which to anchor the medial strap.

In some embodiments, the inventor has recognized that it may be desirable to incorporate shock-absorbing elements into the exoskeleton that can deform when beyond a material yield point, thus absorbing the energy of a potentially injurious inversion torque, with such shock-absorbing elements being sacrificial and replaceable in some embodiments.

The term “yoke” is used herein to describe a portion of an exoskeleton engageable with an upper portion of a footwear, where the yoke is intended to be located near a portion of a user's lower limb, which may also be referred to as a leg, at or above the user's ankle joint and below a knee of the user when worn.

The term “base” is used herein to describe a portion of an exoskeleton engageable with a lower portion of a footwear, where the base is intended to be located near a portion of a user's lower limb at or below the user's ankle joint. The base may be integrally formed with the footwear or may be selectively or permanently attached to the footwear. In some embodiments, the inventor has recognized an advantage to reducing the amount of time a user's foot is in the plantar flexed position while ambulating, reducing the likelihood of a forefoot inversion resulting in a lateral ankle sprain. In some embodiments an elastic tongue is disposed on a dorsal side of the footwear to apply a dorsiflexion assisting torque to the user's foot. Such an elastic tongue may pull the user's foot from a plantar flexed position to a neutral position, reducing the amount of time a user's foot is in the plantar flexed position while ambulating, and reducing the likelihood of a forefoot inversion resulting in a lateral ankle sprain.

The term “sagittal plane,” also known as the “longitudinal plane”, is used herein to define a vertical plane which spans from the front to the back of the user such that the plane anatomically defines right and left halves of a user's body. This term is used herein in reference to the direction of propulsive movement of a user's body during a gait cycle where the general direction of movement of a user during forward movement (e.g., walking, running, etc.) may be oriented in a horizontal direction parallel to the ground and the sagittal plane when the footwear is disposed on a supporting underlying surface.

The term “frontal plane” is used herein to define a vertical plane which spans from the left to ride side of the user such that the plane anatomically defines front and back halves of a user's body. This term is used herein in reference to the direction of lateral support of a user's body during the gait cycle wherein the lateral direction may be taken in a horizontal direction parallel to the ground and the frontal plane when the footwear is disposed on a supporting underlying surface.

The term “anterior” is used herein to describe a direction that is oriented to the front of a foot of the user. In particular, the anterior direction may be further defined as the direction extending towards the user's toes in the sagittal plane.

The term “posterior” is used herein to describe a direction that is oriented to the back of a foot of the user. In particular, the anterior direction may be further defined as the direction extending towards the user's heel in the sagittal plane.

The term “lateral side of footwear” is used herein to describe a portion of the footwear that is oriented to the outside of a foot of a user. In particular, the lateral side may be further defined as the side of the footwear that is closer to the digitus minimus pedis (i.e., the little toe) of a user's foot.

The term “medial side of footwear” is used herein to describe a portion of the footwear that is oriented to the inside of a foot of a user. In particular, the medial side may be further defined as the side of the footwear that is closer to the hallux (i.e., the big toe) of a user's foot.

The term “dorsal side of footwear” is used herein to describe a portion of the footwear oriented to a top of a foot of a user.

The term “forefoot region of footwear” is used herein to describe a portion of footwear adjacent to the forefoot region of a user's foot which includes the metatarsals and the phalanges of the user's foot.

The term “hindfoot region of footwear” is used herein to describe a portion of footwear adjacent to the hindfoot region of a user's foot which includes the talus and calcaneus of the user's foot.

The term “propulsive support” is used herein to describe the promotion of plantar flexion motion in the sagittal plane of a user's foot during a gait cycle prior to toe-off.

The term “gait cycle” is used herein to describe the various movements a human leg and ankle system moves through during each step while ambulating.

The gait cycle may begin with the first touch of the foot to the ground. This first touch begins the cycle at 0% and the moment immediately prior to the following touch to the ground of the same limb may represent 100% of a cycle. In the normal walking gait, the ankle may experience a small amount of extension after initial contact leading to plantar flexion during the first 10-15% of the cycle, commonly referred to as a loading response. This is then followed by dorsiflexion motion, reaching a midstance, where the user's leg is approximately perpendicular with a support surface which the user is walking on. Dorsiflexion continues to increase after the midstance.

Maximum dorsiflexion is typically achieved at initial heel lift and prior to the initial contact of the opposite foot. This is followed by rapid plantar flexion motion associated with push off. In the push-off phase, the ankle plantar flexes through toe off. This is followed by a swing phase with the foot traveling in the air. During the swing phase, the foot dorsiflexes to a neutral position preparing it for the next cycle.

For simplicity, the ankle system motion during the periods of increasing flexion after initial contact and loading response, through mid-stance, through heel lift, to peak dorsiflexion will be referred to as “dorsiflexion” herein; and the ankle system motion during the periods of increasing extension found during opposite foot contact through toe off will be referred to as “plantar flexion” herein.

Turning to the figures, specific non-limiting embodiments are described in further detail. It should be understood that the various systems, components, features, and methods described relative to these embodiments may be used either individually and/or in any desired combination as the disclosure is not limited to only the specific embodiments described herein.

FIGS. 1-3 show top, lateral, and medial views, respectively, of footwear 100, with footwear upper 101 according to an embodiment. As discussed above, the inventor has recognized an advantage to creating a connected force path between lateral forefoot region 102 and medial hindfoot region 104 in order to increase ankle inversion resistance when a user's foot is in the plantar flexed position and/or in the neutral position. Therefore, in some embodiments, the footwear includes a strap 200, the strap including a lateral strap portion 202 configured to connect to the lateral forefoot region 102, and a medial strap portion 204 configured to connect to the medial hindfoot region 104. The lateral and medial strap portions may be aligned such that a force transmitted from the medial strap portion 204 is directed to the lateral strap portion 202 along dorsal portion 201 of the connected force path. Such a configuration may allow for a continuous connected force path between the lateral forefoot region and the medial hindfoot region when the strap portions 202 and 204 are connected The strap 200 may be supported along the medial hindfoot region with heel counter 302. As a result, as the lateral forefoot region 102 of the foot begins to invert, the heel counter 302 resists inversion in the hindfoot region and applies an inversion resisting tension to the lateral forefoot region 102 through strap 200 to reduce the lateral torque the lateral forefoot region experiences. In some embodiments, the strap portions 202 and 204 have an axial stiffness greater than a stiffness of adjacent portions of the footwear 100 oriented in a direction aligned with the strap portions 202 and 204.

As discussed above, in some embodiments, it may be desirable for the strap 200 to be configured to apply the inversion resisting tension during inversion without requiring the user to perform an additional step of securing the strap. It may also be desirable for the level of inversion resisting tension applied by the strap during ankle inversion to be adjustable. In some embodiments, the lateral strap portion and medial strap portion may be incorporated into a closure system 108 of the footwear 100, such that securing the footwear 100 to the user's foot also sets the level of inversion resisting tension the strap 200 applies. Closure system 108 may be any suitable closure system (e.g. laces, touch fastener strap, etc.). For instance, as seen in FIG. 1, a lacing system with lace 110 is used as the closure system 108. Lace 110 may be a single continuous lace, or a combination of multiple laces. The lateral strap portion 202 includes lateral strap eyelets 112 for receiving lace 110, and the medial strap portion 204 includes medial strap eyelets 114 for receiving lace 110. The lace 110 of the closure system 108 is configured to be received through the lateral strap eyelets 112 and medial strap eyelets 114, as well as lateral footwear eyelets 113 and medial footwear eyelets 115. In such a configuration, as the lace 110 is tightened, the lateral strap portion and medial strap portion are pulled together, tightening the strap and increasing the amount of inversion resisting tension applied through the strap 200 when the ankle inverts.

In some embodiments, it may be desirable for the closure system 108 to secure a portion of the footwear adjacent to the strap to the user's foot in a direction approximately parallel to a dorsal portion 201 of the force path of the strap 200, the dorsal portion 201 extending in an axial direction between the lateral strap portion 202 and medial strap portion 204. Such a configuration may allow for the strap portions to be properly aligned when the footwear is secured onto the user's foot, and may allow the closure system 108 to transfer the inversion resisting tension along the force path. As best seen in FIG. 1, in some embodiments, the closures system 108 may be disposed asymmetrically, such that the closure system 108 extends approximately parallel to the dorsal portion 201 of the force path. For instance, when the closure system 108 is a lacing system, the lateral strap eyelets 112 and/or lateral footwear eyelets 113 may be disposed anterior to the corresponding medial strap eyelets 114 and/or medial footwear eyelets 115. As a result, at least some portions 116 of the lace 110 extend approximately parallel to the dorsal portion 201 of the force path. Such a configuration allows for the strap to be disposed at an optimal angle when the lacing system is tightened, and allows the lacing system to transfer the inversion resisting tension between the strap portions at the optimal angle, resulting in a more optimal force path. In some embodiments, the lace portion(s) 116 may extend at an angle offset relative to the dorsal portion 201 of the force path. In some embodiments, the lace portions may be between 0° and 20° offset relative to the dorsal portion 201 of the force path. In some embodiments, different lace portions 116 may extend at different angles offset relative to the dorsal portion 201 of the force path. The inventor has recognized that conventional lacing arrangements may exhibit an undesirable amount of hysteresis when the medial eyelets are shifted along the longitudinal axis of medial eyestay because there may be limited or no reciprocal force on the lateral side of the footwear. Thus, the inventor has recognized benefits associated with arranging the eyelets asymmetrically with the medial eyelets disposed proximal to the ankle of the user and the lateral eyelets are disposed distal to the ankle of the user. Such a configuration may serve to enable a more rapid onset reciprocal force in the lateral eyelet, thereby reducing hysteresis.

The lateral strap portion 202 may connect to the lateral forefoot region 102 at any suitable location which allows for the application of the inversion resisting tension without interfering with operation of the footwear 100 during ambulation. In some embodiments a posterior end portion 208 of the lateral strap portion 202 may be configured to connect to the lateral forefoot region 102 at a first location 120 aligned with and/or posterior to the user's 5th Metatarsophalangeal joint when the footwear 100 is worn by the user. In some embodiments, the posterior end portion 208 is configured to connect to the lateral forefoot region 102 of the footwear 100 at the first location 120 and an anterior end portion 210 is configured to connect to the lateral forefoot region at a second location 122 anterior to the user's 5th Metatarsophalangeal joint when the footwear is worn by the user.

As discussed above, the inventor has recognized an advantage to connecting and supporting the strap with the heel counter 302 relatively high on the medial hindfoot region in order to apply the inversion resisting tension at a more optimal angle. The inventor has therefore recognized an advantage to incorporating an enlarged heel counter 302 as compared to conventional heel counters to the heel counter 302 may support the strap from a more optimal position then would be possible with conventional heel counters. In some embodiments, the enlarged heel counter 302 may extend further anteriorly and or further up on the footwear 100 as compared to conventional heel counters. In some embodiments, the medial strap portion 204 may be configured to extend across a section of the medial hindfoot region aligned with a portion of the user's talus when the footwear is worn by the user, and the heel counter 302 may extend at least to the section of the medial hindfoot region 104 aligned with a portion of the user's talus and be configured to support the medial strap portion in that section. In some embodiments, the medial strap portion 204 extends proximal to (e.g. directly underneath the axis of rotation 106 of the user's ankle when the footwear is worn by the user, and heel counter 302 may extend at least to directly underneath the axis of rotation 106 and be configured to support the medial strap portion directly underneath the axis of rotation 106. In some embodiments, the medial strap portion 204 may extend across a section disposed underneath the axis of rotation 106 of the user's ankle when the footwear is worn by the user, and heel counter 302 may extend at least to that section disposed underneath the axis of rotation 106 and be configured to support the medial strap portion. In some embodiments, the medial strap may extend across the section disposed underneath the axis of rotation of the user's ankle at a distance of greater than or equal to 0 mm (i.e., the medial strap is positioned at the axis of rotation), 1 mm, 3 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, or greater. Likewise, in some embodiments, the medial strap may extend underneath the axis of rotation at a distance of lesser than or equal to 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, or less. In some embodiments, the heel counter 302 may extend anterior to the axis of rotation 106 and may be configured to support the medial strap portion along a section anterior to the axis of rotation. In some embodiments, the heel counter 302 is an enlarged heel counter (e.g. extends further anteriorly and/or extends further upward) as compared to conventional heel counters to allow for the heel counter 302 to support the strap along the sections of the medial hindfoot region discussed above.

As discussed above, in some embodiments, it may be desirable to incorporate the strap 200 into an exoskeleton 300, the exoskeleton 300 configured to provide propulsive support to a user while ambulating. It should be understood that the strap 200 discussed above may be used in conjunction with an exoskeleton, such as the exoskeleton 300 described below but such usage is not required. In some embodiments, the heel counter 302 may be configured to act as base 302 of exoskeleton 300. Base 302 may be configured to secured to a user's foot when the footwear is worn by the user. The exoskeleton 300 may also include a yoke 304 connected to the base via rotatable connections 306 and configured to contact a front of the user's leg above the user's ankle and below the user's knee when the footwear 100 is worn by the user. In some embodiments, the axis of rotation of the rotatable connections 306 may be approximately aligned with the axis of rotation 106. In some embodiments, the exoskeleton 300 may include rotatable connections 306 disposed on medial and lateral sides of footwear 100. The exoskeleton 300 may also include at least one spring 308 configured to connect between the base 302 and the yoke 304. As disclosed herein, the exoskeleton may further include one or more shock-absorbing elements configured to absorb the energy of a potentially injurious inversion torque. In some embodiments, the one or more shock-absorbing elements may be secured to the straps of the footwear (e.g., strap 200).

As a user ambulates during their gait, their leg rotates about the axis of rotation 106 relative to their foot. Because base 302 is secured to the user's foot, and yoke 304 contacts the front of the user's leg, the yoke 304 rotates about the rotatable connections 306 relative to the base 302 as the user's leg rotate relative to their foot. As the user dorsiflexes, the yoke rotates in a first direction relative to the base 302. As the yoke rotates in the first direction, the spring 308 is deformed from an original configuration (e.g. an unstretched/uncompressed configuration when the user's foot is in the neutral position), storing potential energy. As a user plantarflexes their foot, the yoke rotates in a second direction relative to the base, and the elasticity in the spring causes the spring to return to the spring's original configuration. As the spring 308 returns to the original configuration, the spring exerts a plantar flexion assisting torque on the user's foot, providing propulsive support to a user while the user is ambulating.

It should be understood that the spring(s) 308 may be any elastic device or component which may store mechanical potential energy during deformation. Thus, any suitable type of spring may be used to promote the storing and/or releasing of energy, such as elastic cords, elastic bands, bungee cords, elastic sheets, elastic ribs, shaped elastic components (e.g., formed of any suitable shape from injection-molding, compression molding, 3D printing, etc.), die-cut elastic components, elastic-reinforced fabrics or other structural members, bent wire springs, linear springs, helical linear springs, rotational springs, and/or any other suitable spring capable of elastically deforming to store and release energy. It should be understood that a spring 308 may be appropriately configured to provide a spring stiffness of greater than or equal to 500 N/m, 1,000 N/m, 20,000 N/m, combinations between or equal to any of the forgoing, and/or any other suitable spring stiffness as values both greater and lesser than those noted are also contemplated. The spring may also be comprised of suitable elastic or elastomeric materials such as elastomers, rubbers, silicones, thermoplastics, urethanes, or any other suitable elastic material. In some embodiments, the spring may be a composite spring, including multiple suitable materials which in combination provide desired mechanical spring properties.

Any number and/or type of spring may be attached to the footwear body and/or the exoskeleton in any suitable arrangement as the disclosure is not so limited. For instance, as seen in FIGS. 2 and 3, the spring 308 is integrally formed with the footwear body 100. However, the spring(s) may also be located external and/or external to the footwear body 100 as the disclosure is not so limited.

As discussed above, in some embodiments, it may be desirable for footwear 100 to include an elastic tongue 130 disposed on a dorsal side of footwear 100 and configured to apply a dorsiflexion assisting torque to the user's foot and bias the user's foot to a neutral position. Such a configuration may be desirable to minimize the amount of time the user's foot spends in the plantar flexed position, limiting the likelihood of a forefoot ankle inversion in the plantar flexed position. In some embodiments, such a configuration may also provide drop-foot support. As would be appreciated by one of skill in the art, “drop-foot” refers to conditions that make it difficult for users to lift toes off the ground during the swing phase of gait, thus resulting in the dragging of toes and the creation of a fall-risk. Drop foot may be associated with dorsiflexor insufficiency and a user's inability to lift their foot, also known as a flaccid drop foot. Drop foot may be associated with plantar flexor oversufficiency, also known as spasticity. Such conditions are common after a stroke or the like. In some embodiments, when footwear 100 is secured to the user's foot, closure system 108, and/or a supplementary securing system may be configured to hold elastic tongue 130 against the user's foot and/or leg. As the user plantar flexes their foot during ambulation, the elastic tongue stretches from an original configuration (e.g. an unstretched configuration when the user's foot is in the neutral position). The elastic tongue will then exert a dorsiflexion assisting torque on the user's foot when plantar flexed as the elasticity of the elastic tongue 130 biases the tongue to the original configuration. In some embodiments, the elastic tongue 130 may also be configured to deform (e.g. compress) during dorsiflexion, such that the elastic tongue exerts a plantar flexion assisting torque on the user's foot during ambulation which tends to bias the user's foot to the neutral position form the dorsiflexed position. In some embodiments, the elastic tongue may provide propulsive support along with the exoskeleton 300. In some embodiments, the elastic tongue may provide propulsive support even if exoskeleton 300 is not incorporated into footwear 100.

The elastic tongue may have any suitable elasticity including, but not limited to greater than or equal to 1 N/mm, 2 N/mm, 3 N/mm, 4 N/mm, 5 N/mm, 6 N/mm, 7 N/mm, 8 N/mm, or greater. Likewise, in some embodiments, the elastic tongue may have an elasticity lesser than or equal to 10 N/mm, 9 N/mm, 8 N/mm, 7 N/mm, 6 N/mm, 5 N/mm, 4 N/mm, 3 N/mm, or lesser. In some embodiments, the elastic tongue may be configured to stretch in its axial length at a suitable percentage distance relative to its original length of greater than 3%, 5%, 10%, 15%, 20%, 25%, 30%, or greater. Likewise, the elastic tongue may be configured to stretch in its axial length at a suitable percentage distance relative to its original length of lesser than or equal to 35%, 34%, 33%, 32%, 31%, 30%, 25%, 20%, 15%, 10%, or lesser.

FIG. 4 shows an embodiment of an article of footwear 400 having a footwear body 401 that may be incorporated with the above disclosed embodiments of a footwear. A resilient sole plate 402 may be received within a bottom portion 403 of the footwear body 401. The inventor has recognized benefits associated with providing a resilient sole plate 402 to help provide elastic resistance to the plantar surface of the foot in two directions, e.g., in the sagittal plane bending of the foot along the MTP joint, and in the frontal plane inversion/eversion of the forefoot. Thus, the sole plate 402 may be configured to bias the footwear back to a neutral configuration when deflected in either of these directions in the sagittal plane. In some embodiments, the inventors have recognized that the combination of a resilient sole plate together with the embodiments of straps disclosed herein can provide overall augmented protection. In some embodiments, the resilient sole plate 402 may be constructed of any suitable materials including, but not limited to carbon fiber, other high strength fibers, plastics, polymers, fabrics, high elasticity metals, composites of the forgoing, and/or any other suitable material capable of elastically deforming in the above noted directions within a typical range of motion of a user during walking and other motion cycles as the disclosure is not so limited.

In some embodiments, the inventor has recognized benefits associated with providing a resilient sole plate, an exoskeleton, shock-absorbing elements in the exoskeleton, and/or an elastic tongue as described in the above embodiments together in a singular footwear system to provide overall augmented protection from ankle inversion injuries.

While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art. Accordingly, the foregoing description and drawings are by way of example only.