The present invention relates to functional footwear suitable for weightlifting, and in particular to a heel-lift assembly detachably mountable to a sole of a shoe that is adapted to improve the user's weightlifting technique, consequently improving performance and safety during weightlifting.

INTRODUCTION In weightlifting, such as Olympic weightlifting (clean & jerk, snatch), the technique for lifting the weight, as well as, the equipment used to support the technique and the lift, have evolved greatly over a period of many years. The evolution of the technique is connected to improved biomechanical efficiency, including changes in the method of moving the body under the barbell during the lift, and consequently shifting the emphasis away from employing muscles of the upper extremities towards the muscles of the lower extremities.

As a result, in the early 1940's and 1950's, the so called "squat-style" technique has been introduced, where the weightlifter simply moves his feet to the side and fully bends his knees, hips and ankles to squat down under, and "receive" the barbell at the chest for the clean & jerk, or overhead for the snatch. This technique has proven to be superior to all other lifting techniques. However, it was absolutely imperative that both feet are rested flat on the floor, since the weightlifter can lose balance very easily if the heels rise from the floor when in the deep squat position. Figure 1 depicts a weightlifter 10 in the deep squat position with the weight 20 lifted over the head. Both feet 30 are substantially parallel and spread apart to achieve the deepest possible squatting position with the shins tilted forward. The extreme bent at the knees and ankles forces the heels to rise off the floor by a specific angle a. Consequently, a weightlifting shoe having a raised heel portion was developed, allowing the weightlifter to squat down with a reasonably vertical position of the trunk, fully bent knees, forward tilted knees and feet resting flat on the floor, and therefore providing means where the lowest stable position to support the barbell became possible, resulting in a much improved technique and considerable heavier weights being lifted. In particular, Olympic weightlifting shoes typically have a minimum of about 1.3 cm to about 2.5 cm heel, which allows to utilize every aspect of the musculature employed for the lift and allowing the lifter to squat into a deeper position due to the increased range of motion for the ankle joint. So called hybrid Fitness sports, such as CrossFit, promote a broad range of strength and conditioning programs, including, inter alia, Olympic weightlifting, as well as, sprinting, jumping, rope climbing, gymnastic exercises and many more, which are used in combination to evaluate the overall fitness of an athlete. Each one of the numerous disciplines has their own specialist "gear", "kit" or equipment that may help maximizing the athlete's performance in the individual discipline, such as, for example, specialist weightlifting shoes for the Olympic weightlifting workout. However, many athletes may not have the resources to purchase specialist "kit" for every possible discipline that may come up in, for example, a CrossFit competition and/or workout. Also, the space required to store all the specialist "kit", "gear" or equipment, in order to make it available at every occasion, may be far to great to be practically implementable. In addition, recreational athletes, such as typical members of a health club or local gym, may not want to purchase and/or use specialist weightlifting shoes, but may still be interested to occasionally benefit from the specific features provided by such specialist weightlifting shoes.

Accordingly, it is an object of the present invention to provide an accessory or assembly that can be used in combination with any multi-purpose footwear, such as a general-purpose sports shoe or trainer, to provide the advantages of at least one of the specialist "kit", "gear" or equipment. In particular, it is an object of the present invention to provide an assembly that, in combination with any general footwear, is adapted to provide at least some of the advantages of a specialist Olympic weightlifting shoe, but which also allows the footwear to be transformed back to used in other disciplines without any of the drawbacks that may be caused by the specialist feature.

SUMMARY OF THE INVENTION

Preferred embodiments of the invention seek to overcome one or more of the above disadvantages of the prior art.

According to a first aspect of the present invention, there is provided a heel-lift assembly for an article of footwear, comprising:

a heel-lift base member, comprising an upper surface and a lower surface, and demountably attachable to a heel portion of an outsole;

at least one first fastening member adapted to secure said heel-lift base member to the outsole of an article of footwear, and

wherein said heel-lift base member is adapted to raise the heel portion by a predetermined amount with respect to a toe portion of the outsole, and wherein the heel-lift base member is adapted to provide structural support to a foot over the entire raised heel portion. This provides the advantage of a modular specialist weightlifting feature that can be removably secured to any shoe, such as a sports shoe, so as to temporarily transform the shoe, e.g. a general purpose sports shoe, into a specialist weightlifting shoe, entailing at least some of the benefits provided by specialist Olympic weightlifting shoes, but without the need to purchase a dedicated pair of Olympic weightlifting shoes.

Preferably, the at least one first fastening member may comprise a lip protruding from an outer edge of said upper surface, and adapted to matingly and fixedly engage with the heel portion of the outsole.

This provides the advantage of preventing any movement of the shoe sole mounted to the heel-lift assembly past the lip, so as to provide a guide when mounting the engaging heel portion of the shoe sole, as well as a retainer suitably dimensioned to fix the heel-lift assembly to the heel portion of the shoe sole. For example, the lip may be dimensions such that it engages with the lateral surface of the heel portion of the shoe sole via a press-fit, i.e. the lip may have to "stretch" over the lateral surface of the heel portion of the shoe sole, creating sufficient friction between the inner surface of the lip and the lateral surface of the heel portion of the shoe sole to fixedly attach the heel-lift assembly to the heel portion of the shoe sole. In an alternative example, the lip may be dimensioned such that it purely functions as a "stopper" that is adapted to prevent the heel portion of the shoe sole to slide off the upper surface of the heel-lift base member.

Advantageously, the heel-lift assembly may further comprise a second fastening member adapted to fixedly engage said heel-lift base member with an upper of the article of footwear. Preferably, the heel-lift assembly may further comprise a passage through said heel-lift base member that is adapted to receive and engage said second fastening member. Advantageously, at least part of said passage is reinforced with a reinforcement member. Preferably, the second fastening member is a strap. This provides the advantage of providing a secure fit of the heel-lift assembly to the heel portion of the shoe. In addition, the strap may also provide the advantage to secure the foot within the shoe the heel-lift assembly is mounted to, since it allows to apply a tightening force from the upper in a region of the inferior extensor retinaculum towards the calcaneus of the foot, therefore, pressing the heel of the foot further into the heel portion of the shoe. This additional fixture may prevent slippage of the foot within the shoe at a heavy load.

Advantageously, said upper surface of said heel-lift base member may be adapted to cooperate with heel portion of the outsole so as to minimize, or prevent, any movement of said heel-lift base member relative to the external surface of the sole when mounted. Preferably, said upper surface may further comprise a contour and/or profile adapted to maximise friction between the heel portion of the outsole and the upper surface.

Said upper surface may be inclined with respect to said lower surface so as to define a predetermined acute angle.

This provides the advantage of a suitable fit and inclination of the athletes shoe to maximise safety and performance during the exercise. Alternatively, said angle may be selectively adjustable. In particular, the angle may be selectively adjustable by gradually increasing the distance between the upper and the lower surface of the heel-lift base member, for example, by adding additional layers to, or suitable inserts into the heel-lift base member. Said heel-lift base member may be adapted to structurally support the weight of a foot from a posterior end of the foot to at least the anterior end of the calcaneus of the foot. Advantageously, said lower surface of the heel-lift base member and the toe portion of the outsole not raised by said heel-lift assembly, form a planar surface equivalent to the outsole of the article of footwear.

This provides the advantage of distributing the load over a larger area and/or the whole surface area of the shoe sole and foot.

Preferably, said heel-lift base member may be wedge shaped. Advantageously, said heel-lift base member may be made from resilient material. Even more advantageously, said resilient material may be made from a polymer material. BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described, by way of example only and not in any limitative sense, with reference to the accompanying drawings, in which:

Figure 1 shows a weightlifter using the "squat-style" technique to get under the weight in the deepest squat position, and the lift angle of the heel due to the extreme tilt of the shin;

Figure 2 shows a preferred embodiment of heel-lift assembly of the present invention including (a) a perspective view, (b) a rear view and (c) a side view of the heel-lift assembly;

Figure 3 shows lateral views of the heel-lift assembly mounted to the heel portion of a general purpose shoe using (a) a thin standard strap, (b) an alternative strapping feature that is integral with the heel-lift base member and (c) a strapless feature, i.e. the lip of the heel-lift base member is in engagement with the heel portion of the shoe via a press-fit;

Figure 4 shows the preferred embodiment of the heel-lift base member of the present invention from (a) a top view, (b) a lateral view, (c) a medial view, and (d) a rear view,

Figure 5 shows (a) a rear view, (b) a cross section at B-B, and (c) a cross section at C-C of the heel-lift base member in Figure 4(a), and

Figure 6 shows (a) bottom and (b) top view of the preferred embodiment of the heel-lift assembly including a strap..

DETAILED DESCRIPTION OF EMBODIMENTS

Referring now to Figure 2 (a), (b) and (c), a preferred example of the heel-lift assembly 100 comprises a heel-lift base member 102 and a strap 104. The heel-lift base member 102 is wedge shaped having a lower, ground engaging surface 106 and an upper, shoe engaging surface 108. The upper surface 108 is inclined with respect to the lower surface 106 by an acute angle of about 36°. However, the two surfaces 106 and 108 may include any other suitable acute angle. In particular, heel- lift assemblies featuring different angles may be used by athletes of different height or stature, and for different purposes. The heel-lift base member 102 is shaped so as to provide a complementary footprint to a typical heel portion of a shoe sole. A lip 110 or side wall protrudes upwardly from the edge of the upper surface 108 so as to create a recess that matingly fits onto the heel portion of a shoe sole. The overall dimensions of the heel-lift assembly 100 is in accordance to a predetermined shoe size or a limited size range, i.e. an embodiment of the heel-lift assembly of a first size may be suitable to fit the heel portions of a limited range of shoes sizes, or may be specifically dimensioned for the heel portion of a particular shoe size.

The heel-lift base member 102 further includes a transverse passage 112 through the body of the heel-lift base member 102. The strap 104 is threaded through the passage 112 allowing the heel-lift base member 102 to be fastened to the heel portion of a shoe by engaging the posterior edge of the heel portion of the shoe with the inner edge formed by the lip 110 and the upper surface 108 and tying the strap 104 on the opposite side at a region of the upper of the shoe that is close to the ankle or in line with the inferior extensor retinaculum.

Figure 3 (a), (b) and (c) shows various embodiments of the heel-lift assembly 100 when mounted to a shoe. Figure 3(a) shows the preferred embodiment, where a separate strap 104 is threaded through the passage 112, tied around the upper of the shoe and the foot and closed with a clasp 114. Any other suitable means may be used to fasten and tighten the strap around the upper/foot, such as, for example, a Velcro™ connection or a buckle mechanism.

Figure 3(b) depicts an alternative embodiment 200 of the heel-lift assembly, where the strapping member 204 is an integral part of the heel-lift base member 202. However, it is understood by the person skilled in the art that any variation of a strapping member 104, 204 and strapping mechanism may be used to attach or mount and secure the heel-lift base member 102, 202, 302 to the heel portion of a shoe sole.

Figure 3 (c) depicts yet another alternative embodiment 300 of the heel-lift assembly that is mountable to the heel portion of a shoe sole without a strapping member. In particular, the lip 310 is formed in such a way that a press-fit or friction fit is provided with the heel-portion of the shoe. The lip 310 is made of suitably resilient and flexible material to be pulled up and over at least part of the heel portion of the shoe in order to provide a secure fit between the heel-lift assembly and the shoe.

Preferably, the upper surface 108 of the heel-lift base member 102 has a profile pattern and/or contour that maximises the friction between the engaging shoe sole and the heel-lift assembly 100 to minimise slip of the shoe sole from the upper surface 108. The profile pattern or contour may be a tread pattern specifically suited for shoe sole material and/or for displacing any fluid that may be trapped between the surfaces.

Also, when mounted, the heel-lift assembly 102 preferably extends from the posterior edge of the heel portion of the shoe sole to a region past the posterior metatarsal base, i.e. into the medial arch, and forms a continuous and flat surface with the remaining ground engaging front portion of the shoe sole. However, for specific purposes, any length of the heel-lift base member may be used.

Figures 4 (a) to (d), 5 (a) to (c) and 6 (a) and (b) depict various detailed views of the preferred embodiment of the heel-lift base member 102 of the present invention including a cross section view through the heel-lift base member 102 at B-B and at C-C. The heel-lift member 102, 202, 302 and/or strap 104, 204 may be made of any material suitable to raise the heel and provide structural support to the heel portion of the foot during weightlifting exercises. It will be appreciated by persons skilled in the art that the above embodiment has been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departing from the scope of the invention as defined by the appended claims.