WO2022185059A1

WO2022185059A1 - An aid for fitness training

Info

Publication number: WO2022185059A1
Application number: PCT/GB2022/050556
Authority: WO
Inventors: Kevin Charles JARRETT; David Riley; James Kennedy
Original assignee: Hammer Fit
Priority date: 2021-03-02
Filing date: 2022-03-02
Publication date: 2022-09-09
Also published as: GB202102936D0; GB2604360A

Abstract

The invention relates to a fitness training aid (50) for joining together a first striking device (42) and a second striking device (44), wherein the fitness training aid (50) comprises a connector (52) in the form of a sleeve that defines an interior surface (54), the connector (52) extending along a longitudinal axis (L) from a first end (52a) to a second end (52b) opposed to the first end (52a), wherein the connector (52) is configured to receive the first striking device (42) at the first end (52a) and the second striking device (44) at the second end (52b), in use. The invention also relates to a fitness training device (10), in the form of a striking device, the fitness training device (10) comprising a handle portion (30) and a head portion (20), wherein the head portion (20) comprises a striking surface (26) and a cavity (70) that extends into the head portion (20) and behind the striking surface (26).

Description

AN AID FOR FITNESS TRAINING

FIELD OF THE INVENTION

The invention relates to the field of equipment for fitness training. In particular, the invention relates to a fitness training aid, a fitness training assembly and a fitness training device.

BACKGROUND

Fitness training, and in particular functional training, has become increasingly popular in recent years. Functional training focuses on movement patterns that are designed to strengthen the body in a way that directly translates to activities in everyday life, with a particular focus on compound movements that engage more than one muscle group at a time. In many cases, the practical application of functional training is to make everyday activities easier to perform.

As functional training has become more popular, so there has been an increased demand for equipment to use while training that extends beyond the traditional boundaries of fitness training equipment, such as dumb bells, bar bells and the like, thereby opening up new methods of training. It is against this background that the invention has been devised.

SUMMARY OF THE INVENTION

Against this background, the invention provides in a first aspect a fitness training aid for joining together a first striking device and a second striking device. The fitness training aid comprises a connector in the form of a sleeve that defines an interior surface, the connector extending along a longitudinal axis from a first end to a second end opposed to the first end. The connector is configured to receive the first striking device at the first end and the second striking device at the second end, in use.

In the context of this invention, the term ‘striking device’ relates to any device specifically adapted for the purposes of striking another object (e.g. the floor or a mat on the floor).

The connector may be made from a flexible material and the interior surface of the connector may define an inner volume having a substantially elliptical cross-section. The elliptical cross- section of the inner volume can allow the connector to receive a correspondingly shaped handle. An exterior surface of the connector may also define a substantially elliptical cross section such that the connector is ergonomically designed to be held by a user. The exterior surface of the connector may also comprise first and second grip portions located at the first and second ends of the connector, respectively, to further assist gripping of the connector by the user.

In the fitness training aid, the connector may comprise a locating element, configured to locate the first striking device relative to the second striking device within the connector, in use.

The locating element may comprise an at least partially circumferential protrusion extending inwardly from the interior surface of the connector. The locating element may be positioned substantially centrally along the connector with respect to the longitudinal axis.

The connector may comprise a first retaining element located toward the first end of the connector and a second retaining element located toward the second end of the connector. The first and second retaining elements may be configured to retain the striking devices within the connector, in use. The first and second retaining elements may together comprise the locating element of the connector.

Each of the first and second retaining elements may comprise at least one protrusion from the interior surface of the connector.

In a second aspect, the invention provides a fitness training assembly, comprising a fitness training aid as described above, a first striking device, and a second striking device. The first striking device is inserted into the first end of the connector and the second striking device is inserted into the second end of the connector.

When assembled, the first striking device may abut a first locating surface of the locating element and the second striking device may abut a second locating surface of the locating element when inserted therein, wherein the first and second locating surfaces are opposed to one another. The first and second striking devices may also engage with the first and second retaining elements of the connector, respectively.

The flexible material of the connector may be selected to permit bending of the assembly along the longitudinal axis under the weight of the first and second striking devices by at least 5 degrees, preferably by at least 10 degrees. The material of the connector may also be selected to permit bending of the assembly along the longitudinal axis under the weight of the first and second striking devices by at most 25 degrees, and preferably by at most 20 degrees. In a third aspect, the invention provides a fitness training device, in the form of a striking device. The fitness training device comprises a handle portion and a head portion, wherein the head portion comprises a striking surface and a cavity that extends into the head portion and behind the striking surface.

The handle portion may extend from a handle surface, wherein the handle surface is adjacent to the striking surface. The handle surface may be defined by a top surface of the head portion.

The cavity may extend into the head portion from a cavity surface, wherein the cavity surface is adjacent to the striking surface and opposed to the handle surface. The cavity surface may be defined by a base surface of the head portion. The cavity may extend into the head portion at least 50% of the height of the head portion, and preferably between 55% and 70% of the height of the head portion.

The fitness training device may include a retaining bore which passes through the handle portion and the head portion to define a channel for receiving a fixing member to provide a mechanical connection between the head portion and the handle portion.

In one embodiment, the retaining bore may be a blind bore which extends perpendicular to the longitudinal axis of the handle portion.

The cavity surface may be substantially planar and may define a base of the fitness training device.

The head portion may be substantially frusto-spherical in shape.

The cavity may be annular in shape.

In certain embodiments, the cavity may comprise a first cavity portion and a second cavity portion. In other embodiments, the cavity may be housed entirely within the head portion and may not comprise any external opening onto the cavity surface.

A fitness training assembly may comprise a first fitness training device and a second fitness training device as described above, and a connector. When assembled from a kit of parts, the first fitness training device may be inserted into a first end of the connector and the second fitness training device may be inserted into a second end of the connector, the second end being opposed to the first end. It will be appreciated that preferred and/or optional features of any aspect of the invention may be incorporated alone or in appropriate combination in one or more of the other aspects of the invention also.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that it may be more easily understood, the invention will now be described, by way of example only, with reference to the following drawings in which:

Figure 1 shows a side view of a fitness training device of a first aspect of the invention;

Figure 2 shows a perspective view of the fitness training device of Figure 1;

Figure 3 shows a bottom view of the fitness training device of Figures 1 and 2;

Figure 4 shows a side view of the fitness training device of Figures 1 to 3, additionally comprising a retaining pin received within a retaining bore;

Figure 5 shows a side view of a fitness training assembly comprising first and second fitness training devices, as in Figures 1 to 3;

Figure 6 shows a perspective view of the fitness training assembly of Figure 5;

Figure 7 shows a side view of a fitness training aid according to a second aspect of the invention;

Figure 8 shows a perspective view of the fitness training aid of Figure 7;

Figure 9 shows a cross sectional view of the fitness training aid of Figures 7 and 8, taken along a plane normal to the axis L;

Figure 10 shows a cross sectional view of the fitness training aid of Figures 7 and 8, taken along a plane containing the axis L;

Figure 11 shows a cross-sectional view of a central portion of an alternative fitness training aid; Figure 12 shows a stiffening element for a fitness training aid;

Figure 13a shows a cross-sectional view of the stiffening element of Figure 12 received within a fitness training aid, taken along a plane containing the axis L;

Figure 13b shows a cross-sectional view of the stiffening element of Figure 12 received within a fitness training aid, taken along a plane normal to the axis L;

Figure 14 shows a perspective view of a head portion of a fitness training device of Figures 1 to 3; and

Figure 15 shows a cross-sectional view of the fitness training device of Figures 1 to 3 comprising the head portion of Figure 14.

DETAILED DESCRIPTION

Figures 1 to 3 show various views of a fitness training device 10 in accordance with a first embodiment of the invention. The fitness training device is a striking device 10 in the form of a hammer and may be considered to extend substantially along a longitudinal axis L. The striking device 10 comprises a head portion 20 and a handle portion 30. The head portion 20 comprises three separate surfaces: a planar base surface 22, a planar top surface 24 opposed to the base surface 22 and a curved striking surface 26, which separates the base surface 22 and the top surface 24 from one another. The base surface 22 acts as a base for the striking device 10, its planar nature allowing the striking device 10 to stand upright when it is rested thereupon. The top surface 24 defines a handle surface at which the handle portion 30 connects to the head portion 20.

The striking surface 26 is curved so as to provide one continuous surface that extends around the entire head portion 20 between the base surface 22 and the top surface 24. The continuous nature of the striking surface 26 avoids edges in the striking surface 26 and maximises the surface area which can be used for striking. As the striking device 10 is intended to be used for fitness training, rather than for any sort of construction purpose, the provision of a continuous and uniform striking surface 26 advantageously allows the user to focus on the movement used in striking, rather than on achieving optimal contact between the striking device and the target. To take a real-world example, when using a sledgehammer to break a wall the striking surfaces are provided at ends of the head portion of the sledgehammer. The positioning of the striking surfaces in the sledgehammer are positioned so as to optimally transfer force from the motion of the sledgehammer to the target and the user must therefore focus on achieving accurate and optimal contact between the striking surfaces and the target for the sledgehammer to be effective. On the other hand, the striking device 10 of the invention allows the user to focus on the movement used for striking, rather than the end goal of optimally transferring force to a target based on the equivalency of different positions around the head portion 20. Functionally, therefore, the manner in which the striking device 10 of the invention is used, and the considerations of use, are quite different to those for a conventional hammer tool.

In embodiments of the invention, the head portion 20 may define a substantially frusto- spherical shape, such that the striking surface 26 substantially defines a zone of a sphere, that is, the curved surface of a sphere cut by two parallel planes. In further embodiments, the head portion 20 may be symmetrical about a plane P normal to the axis L that passes through the head portion 20 mid-way along its height as measured from the base surface 22 to the handle surface 24, such that the handle surface 24 and the base surface 22 define substantially identical circular areas.

As mentioned above, the handle portion 30 extends from a first end 30a, that connects to the handle surface 24 of the head portion 20 along the axis L, to a second end 30b. The handle portion 30 comprises a main body 32, which takes the form of a substantially elliptical cylinder, and a flared connecting portion 34, which extends between the main body 32 and the head portion 20, with a slightly larger cross section at the end that connects to the head portion 20, which corresponds to the first end 30a of the handle portion 30. The elliptical shape of the main body 32 of the handle portion 30 allows the striking device 10 to fit better into the hands of a user, making it more comfortable to hold during use, and particularly considering the types of movement with which the user manoeuvres the striking device 10, in use.

In use, the striking device 10 is designed so that a user strikes a target mat on the floor with the head portion 20 while holding the handle portion 30. In some embodiments, the striking device 10 is a unitary moulded product; this consequently puts great importance on the choice of material used for the handle portion 30 and the head portion 20, which must have a great enough stiffness that the handle portion 30 does not experience a great deal of flexion during striking whilst also being compliant enough to absorb the energy of the strike within the head portion 20 without transmitting vibrations up the handle portion 30 to the user. An important material property of the head portion 20 in particular is its resilience, in other words how much energy that it can absorb under elastic loading.

In other embodiments, the handle portion 30 and the head portion 20 may be formed of separate moulded parts. This may allow tailoring of the material properties of each portion 20, 30 for optimised user comfort and functional purpose, such as making the handle portion 30 from a stiffer material and the head portion 20 from a more compliant material. In one embodiment, the handle portion 30 may be made from a polypropylene outer section, supported and stiffened by a core made from carbon fibre composite. The head portion 20, meanwhile, may be made from a silicone material or a natural rubber material, which is more compliant and resilient than the handle portion 30.

In manufacturing the striking device 10, the head portion 20 may be moulded around the flared connecting portion 34 of the handle portion 30. The shape of the connecting portion 34 therefore prevents the head and handle portions 20, 30 detaching from one another. This effect can be augmented by the inclusion of an open bore traversing the connecting portion 34. When the head portion 20 is moulded around the connecting portion 34, the resin fills the open bore to form a retaining or fixing member (not shown) of the head portion 20, extending through the connecting portion 34 to form a direct mechanical bond between the head and handle portions 20, 30, thus providing an additional means of securing the head and handle portions 20, 30 together.

As an alternative, the head portion 20 may be moulded around a blank, which is subsequently removed, with the flared connecting portion 34 of handle portion 30 inserted into the negative space left by the blank while the head portion is still hot enough to be soft, so that the flared connecting portion 34 can be received within the head portion 20. As the head portion 20 cools, it contracts around the flared connecting portion 34 to retain the handle portion 30 in place.

Regardless of how the striking device 10 is assembled, and referring to Figure 4, subsequent to assembly of the striking device 10 a blind retaining bore 35 may be drilled into the head portion 20 in a direction substantially perpendicular to the axis L that passes through a first side of the head portion 20, through the entirety of (i.e. the full width of) the flared connecting portion 34 of the handle portion 30 and into an opposing side of the head portion 20. The retaining bore 35 defines a channel for receiving a fixing member (37). The fixing member is in the form of a retaining pin 37 which is then inserted into the blind retaining bore 35 such that a first end of the retaining pin 37 is fully received in the blind end of the retaining bore 35 on the opposing side of the head portion 20, while a second end of the retaining pin 37 is located in the first side of the head portion 20. The retaining pin 37 may have a larger diameter than that of the retaining bore 35 to hold the retaining pin 37 in place and prevent egress of the retaining pin 37 out of the open end of the retaining bore 35. For example, the retaining bore 35 may have a diameter of 7 mm, while the retaining pin 37 has a diameter of 8 mm. The retaining bore 35 and retaining pin 37 provide an additional mechanical bond between the head and handle portions 20, 30 to help retain the portions together, and may be used in place of, or in addition to the open bore through the connecting portion 34 discussed above.

Turning now to Figures 5 and 6, a fitness training assembly 40 is shown that comprises a first fitness training device 42 and a second fitness training device 44, both of which take the form of striking devices as described above, and a fitness training aid, referred to generally as 50, in the form of a connection means for the devices 42, 44. The three components of the fitness training assembly 40 are aligned along a common longitudinal axis L, which corresponds to the longitudinal axis L shown in Figures 1 to 3. The fitness training aid 50 is made primarily from a flexible material, such as a rubber material, and extends from a first end 50a to an opposed second end 50b along the common axis L and comprises a connector 52 in the form of a sleeve. Typically, the connector 52 is a moulded part and may be primarily made from a moulded rubber material, such as nitrile butadiene rubber or styrene butadiene rubber, or a combination thereof. Additional components, such as polyvinyl chloride, may also be present. The connector may have a hardness of 85, as measured on the Shore A hardness scale. The connector 52 also extends from a first end 52a to an opposed second end 52b along the common axis L, the ends 52a, 52b of the connector 52 substantially corresponding with the ends 50a, 50b of the fitness training aid 50. The connector 52 is best shown in Figures 7 to 10.

The connector 52 may be hollow and tubular in form. Consequently, the connector 52 defines an interior surface 54. The interior surface 54 of the connector 52 defines an inner volume 56 having a substantially elliptical cross-section, which is configured to substantially match that of the handle portion 30 of the first and second striking devices 42, 44 so that they fit conveniently within the connector 52.

The connector 52 also defines an exterior surface 58 that comprises a first grip portion 60 at the first end 52a of the connector 52 and a second grip portion 62 at the second end 52b of the connector 52. The grip portions 60, 62 each comprise a series of undulating ridges and grooves that run around the circumference of the exterior surface 58 of the connector 52 and are shaped to fit the user’s fingers within the grooves. The grip portions 60, 62 therefore provide an ergonomic means for the user to hold the fitness training assembly 40, whilst also indicating the correct position for the user’s hands while doing so.

It should be understood that, although the inner volume 56 of the connector 52 defines a substantially elliptical cross-section, there is no requirement that the external cross-sections of the connector 52 and/or first and second grip portions 60, 62 are also elliptical. However, since the connector 52 is also designed to be held by a user, an elliptical external cross- section, as shown in Figure 9, may have similar ergonomic benefits to those experienced by the handle portions 30 of the striking devices 42, 44. In other words, there are no functional restrictions on the external cross-section of the connector 52, while the only functional restriction on the internal cross-section is that it must substantially match the cross-section of the handle portion 30.

The connector 52 further comprises a locating element 64, positioned on the interior surface 54 of the connector 52. The locating element 64 takes the form of a protrusion that runs circumferentially around the interior surface 54 and extends inwardly into the inner volume 56. In the examples shown in the Figures, the locating element 64 runs around the entire circumference of the interior surface 54. The locating element 64 therefore represents a localised reduction in the cross-section of the inner volume 56 of the connector 52. Ideally, the locating element 64 is located substantially centrally along the connector 52 with respect to the common axis L. The locating element 64 is configured to locate the first striking device 42 relative to the second striking device 44 within the connector 52, in use. In particular, the locating element 64 provides a stop which serves to limit the extent to which each of the first and second striking devices 42, 44 can be inserted into the inner volume 56.

In addition to the locating element 64, the connector 52 may also comprise first and second retaining elements (not shown). The first and second retaining elements each comprise at least one inwardly extending protrusion from the interior surface of the connector 52 that is configured to engage with corresponding recesses (also not shown) in the handle portions 30 of the first and second striking devices 42, 44, in use. In an example, the first and second retaining elements take the form of a nipple protruding from the interior surface 54 of the connector 52. The first and second retaining elements may be located towards the first and second ends 52a, 52b of the connector 52, or may be located closer towards the locating element 64.

Turning back to the fitness training assembly 40 shown in Figures 5 and 6, the handle portions 30 of the first and second striking devices 42, 44 are inserted into the connector 52 at the first and second ends 52a, 52b, respectively. Both striking devices 42, 44 are inserted into the inner volume 56 to the maximum extent possible, until they engage with the locating element 64, one on each side thereof. In practice, this engagement occurs when the handle portion 30 of the first striking device 42 abuts a first locating surface 66 of the locating element 64 and the handle portion 30 of the second striking device 44 abuts a second locating surface 68 of the locating element 64, with the second locating surface 68 being opposed to the first locating surface 66. This therefore ensures that the first and second striking devices 42, 44 are inserted sufficiently far into the connector 52 for the intended use of the assembly and that they are located centrally and symmetrically within it, thereby ensuring even weight distribution along the fitness training assembly 40.

As shown in Figure 11 , the connector 52 may alternatively comprise two locating elements 64a, 64b, each of which is co-operable with the end of the handle portion 30 of a respective one of the first and second striking devices 42, 44,. The two locating elements 64a, 64b are similar in form to the single locating element 64 described above and are located such that they are substantially equidistant from the centre of the connector along the common axis L. The two separate locating elements 64a, 64b each work in the same way as if there was only one locating element 64 present, to locate the positions of the striking devices 42, 44 when received within the connector. The first locating surface 66 is formed on the outwardly-facing surface of a first one of the locating elements 64a and the second locating surface 68 is formed on the outwardly-facing surface of the second locating element 64b. In other words, the first and second locating surfaces 66, 68 are the surfaces of the locating elements 64a, 64b that are closest to the first and second ends 52a, 52b of the connector 52.

If the connector 52 comprises a retaining element, the or each protrusion of the first and second retaining elements engages with a respective recess on the handle portion 30 of each of the first and second striking devices 42, 44. The retaining element and the locating element (or locating elements) 64 of the connector 52 co-operate such that when the first and second striking devices 42, 44 are correctly located within the connector 52, they will be also be at the correct longitudinal position within the connector 52 for the first and second retaining elements to engage with the corresponding recesses in the respective handle portions 30, rotation of the first and second devices 42, 44 about the common axis L notwithstanding. This engagement retains the first and second striking devices 42, 44 within the fitness training assembly 40 and ensures that they do not fall out of the connector 52.

In the absence of first and second retaining elements, a natural retaining effect may be achieved by the friction generated by between the handle portions 30 of the first and second striking devices 42, 44 and the interior surface 54 of the connector 52. Since the connector 52 and the first and striking devices 42, 44 are moulded products, there is, in general, a high coefficient of friction between the handle portions 30 and the interior surface 54 of the connector 52. Therefore, even in the case where the connector 52 does not comprise retaining elements, the first and second striking devices 42, 44 are still effectively retained within the fitness training assembly 40 through friction alone.

In some embodiments, the first and second retaining elements may also function together as separate locating elements 64 for the first and second striking devices 42, 44. Since the protrusions from the interior surface 54 of the connector 52 correspond to recesses in the respective handle portions 30, engagement between the protrusions and the recesses only occurs when the respective striking device 42, 44 is located at the correct position within the connector 52.

In use, the fitness training assembly 40 is designed primarily for use in training the core and abdominal muscles of the user. The assembly 40 is designed to be gripped by the user at the grip portions 60, 62 on the exterior surface 58 of the connector 52 and moved backwards and forwards by pulling back and pushing forwards their arms. When the direction of movement of the assembly 40 is changed, the inertia associated with the mass of the striking devices 42, 44, and the head portions 20 of the striking devices 42, 44 in particular, causes the connector 52 to bend or flex relative to the axis L. The flexing arises as the central portion of the assembly 40 - the connector 52 and parts of the handle portions 30 inserted therein - changes direction more quickly than the ends of the assembly, which are made up of the heavier head portions 20 and parts of the handle portions 30 not received within the connector 52. This provides a more effective exercise for the core and abdominal muscles than if the assembly 40 were stiff and rigid. The degree of bending of the fitness training assembly 40 along the longitudinal axis L may be at least 5 degrees and may preferably be at least 10 degrees. The degree of bending of the fitness training assembly along the longitudinal axis L may preferably be at most 25 degrees and may preferably be at most 20 degrees in normal use.

In positioning the handle portions 30 at the same distance from the centre of the connector along the common axis L as each other, the locating element, or locating elements, 64 ensures even weight distribution across the fitness training assembly 40 and avoids potential overworking of one side of the user’s body compared to the other. The natural retentive effect of the high coefficient of friction between the handle portions 30 and the interior surface 54 of the connector 52 minimises longitudinal displacement of the first and second striking devices 42, 44 during use of the assembly 40; this effect is augmented by the inclusion of the retaining elements on the interior surface 54 of the connector 52. If the striking devices 42, 44 were to start to slip longitudinally within the connector 52, one of the two striking devices 42, 44 of the assembly 40 may eventually fall out of an open end of the connector 52, which naturally is undesirable and must be avoided. The synergy between the locating element, or locating elements, 64, retaining elements and the natural friction between the connector 52 and handle portions 30 of the striking devices 42, 44 therefore plays an important role in allowing the fitness training assembly 40 to function properly.

The stiffness of the connector 52, and the resulting ease of flexion of the fitness training assembly 40, can be altered by changing the extent to which the locating element 64 protrudes into the inner volume 56, with the connector 52 becoming stiffer as the locating element, or locating elements, 64 protrudes further into the inner volume 56. The stiffness of the connector 52 may also be altered by changing the extent of the length of the locating element, or locating elements, 64 in the direction of the common axis L or by altering the length of the connector 52 itself. It will be apparent that the same effect could be realised by selecting a stiffer material for the connector 52.

Alternatively or additionally to the stiffness-adjusting mechanisms discussed above, the fitness training aid 50 may comprise a stiffening element 80 to increase its stiffness. As will be appreciated from the following description, the stiffening element 80 may take a number of forms that all serve to increase the flexural stiffness of the fitness training aid 50; examples of the stiffening element 80 include ribs or wire strands located along the connector 52. However, the stiffening element 80 is preferably a tubular insert 82, such as that shown in Figure 12, as this is relatively straightforward to manufacture and incorporate into the connector 52.

The insert 82 may be formed of a metal or alloy, such as steel, to provide a significant stiffening effect. As shown in Figure 12, when initially formed the tubular insert 82 may have a substantially circular cross-section. This can, however, be modified if required through deformation, either before or during the moulding process, such that the insert 82 matches either the external or internal cross-section of the connector 52. Alternatively, the insert 82 can be formed at the outset with a cross-section that substantially matches either the internal or external cross-section of the connector 52.

As seen in Figures 13a and 13b, the insert is received entirely within the connector 52 such that no surface of the insert 82 is exposed. This can be achieved by moulding the connector 52 around the insert 82. Although Figure 13a shows a connector 52 with two locating elements 64, it will be appreciated that connectors incorporating only one locating element 64 may also incorporate an insert 82, or other stiffening element 80.

In other embodiments, rather than having an insert which is permanently moulded into the connector 52, the insert may be removable.

In cases where the connector 52 is moulded around the insert 82, the insert may include one or more flow promoters 84 in the form of holes, as seen in Figure 12. The flow promoters 84 enable the liquid precursors used when moulding the connector 52 to more easily flow into the space inside the insert 82, ensuring that the mould is filled and the connector 52 has the desired internal dimensions. This also ensures that there is a strong mechanical bond between the insert and the connector. In Figure 12, three holes 84 are used. By using an odd number of holes 84, the middle hole can conveniently be used to simply locate the insert 82 centrally within the mould and the connector 52, ensuring that the stiffness imparted by the insert 82 is symmetric about the axial centre point.

In Figure 13a, the insert 82 only extends along a central portion of the connector 52. However, the length of the insert 82 can be tailored to fit the stiffness requirements of different connectors 52 and so the insert may be longer, or shorter, than that shown in Figure 13a. Typically, the length of the insert 82 may span between 20-40% of the overall length of the connector 52.

Although the above paragraphs relate to an intended primary use of the invention, the fitness training assembly 40 may also be used for a number of secondary uses. For example, the lighter weight of the fitness training assembly 40 when compared to a traditional bar bell arrangement allows users who may be new to fitness training with free weights to initially practice exercises such as squats, cleans and deadlifts with a far reduced risk of injury, allowing them to learn the correct form and technique for performing such exercises. The invention lends itself especially to the use of striking devices 42, 44 which have a relatively light weight so that the devices can be safely retained within the connector 52 in a way which may not be so secure for heavier devices 42, 44.

Figures 14 and 15 show an alternate embodiment of a head portion 20 for the striking device 10 shown in Figures 1 to 3. The head portion 20 comprises all the features of the head portion 20 of the previous embodiment, but also comprises a cavity 70 that extends into the head portion 20 and behind the striking surface 26. In the embodiment shown in Figure 14, the cavity 70 is annular in form and extends into the head portion 20 from the base surface 22 of the head portion 20, which defines a cavity surface.

In general, the cavity 70 extends into the head portion 20 at least 50% of the height thereof from the cavity surface 22, as can best be seen in Figure 15. Preferably however, the extent of ingress of the cavity 70 into the head portion 20 may be between 55% and 70% of the height of the head portion 20.

The purpose of the cavity 70 in the head portion 20 is to provide damping to the head portion 20 as the striking surface 26 strikes the ground. As a strike occurs, there is localised compression of the head portion 20. The head portion 20 is able to compress into the space of the cavity 70, allowing for dissipation of the energy absorbed by the head portion 20 in contact with the ground and preventing vibrations from travelling through the head portion 20 and up the handle portion 30 to the hands of the user. The cavity 70 therefore increases user comfort during use of the striking device 10.

The cavity 70 may take different forms to that shown in Figure 14. For example, the cavity 70 may comprise a first cavity portion and a second cavity portion that together make up a nearly annular cavity 70. The first and second cavity portions may each be substantially semi-circular in cross-section. Alternatively, the cavity 70 may be housed entirely within the head portion 20 and does not comprise any external opening onto the cavity surface 22. In this case, it may be necessary to manufacture the head portion 20 in two parts that are subsequently joined together.

It will be apparent that the first striking device 42 and the second striking device 44 of the fitness training assembly 40 described above may correspond to the striking device 10 of the embodiment shown in Figure 14, as well as that shown in Figures 1 to 3.

While description here has focused on the use of the fitness training aid 50 as a connector for use in the fitness training assembly 40, the fitness training aid 50 may also find use on its own to train the grip strength of a user. The flexible nature of the fitness training aid 50 means that a user holding onto the grip portions 60 of the fitness training aid 50 can train their crush grip by squeezing the grip portions. Crush grip is an important component in a number of sports and activities. It will be appreciated that many alterations may be made to the embodiments of the invention described above and shown in the Figures, even beyond those already discussed in the description, while still falling within the scope of the appended claims.

Claims

1. A fitness training aid (50) for joining together a first striking device (42) and a second striking device (44), wherein the fitness training aid (50) comprises a connector (52) in the form of a sleeve that defines an interior surface (54), the connector (52) extending along a longitudinal axis (L) from a first end (52a) to a second end (52b) opposed to the first end (52a), wherein the connector (52) is configured to receive the first striking device (42) at the first end (52a) and the second striking device (44) at the second end (52b), in use.

2. The fitness training aid (50) of Claim 1, wherein the connector (52) is made from a flexible material.

3. The fitness training aid (50) of Claim 1 or Claim 2, wherein the interior surface (54) defines an inner volume (56) having a substantially elliptical cross-section.

4. The fitness training aid (50) of any preceding claim, wherein the fitness training aid (50) further comprises a stiffening element (80).

5. The fitness training aid (50) of Claim 4, wherein the stiffening element (80) is a tubular insert (82).

6. The fitness training aid (50) of Claim 4 or Claim 5, wherein the stiffening element (80) is made of metal.

7. The fitness training aid (50) of any of Claims 4 to 6, wherein the connector (52) of the fitness training aid (50) is a moulded product and is moulded around the stiffening element (80) so that the connector (52) entirely surrounds the stiffening element (80).

8. The fitness training aid (50) of Claim 7, wherein the stiffening element (80) comprises flow promoters (84) that promote flow of a liquid precursor around the stiffening element (80) when moulding the connector (52).

9. The fitness training aid of Claim 8, wherein the flow promoters (84) take the form of holes in the stiffening element (80).

10. The fitness training aid (50) of any preceding claim, wherein the connector (52) comprises one or more locating elements (64), configured to define first and second locating surfaces (66, 68) to locate the first striking device (42) relative to the second striking device (44) within the connector (52), in use.

11. The fitness training aid (50) of Claim 10, wherein the or each locating element (64) comprises an at least partially circumferential protrusion extending inwardly from the interior surface (54) of the connector (52).

12. The fitness training aid (50) of Claim 10 or Claim 11, wherein the or each locating element (64) is positioned substantially centrally along the connector (52) with respect to the longitudinal axis (L).

13. The fitness training aid (50) of any of Claims 10 to 12, wherein the connector (52) comprises a first retaining element located toward the first end (52a) of the connector (52) and a second retaining element located toward the second end (52b) of the connector (52), the first and second retaining elements being configured to retain the striking devices (42, 44) within the connector (52), in use.

14. The fitness training aid (50) of Claim 13, wherein each of the first and second retaining elements comprise at least one protrusion from the interior surface (54) of the connector (52).

15. A fitness training assembly (40), comprising the fitness training aid (50) of any preceding claim, a first striking device (42) inserted into the first end (52a) of the connector (52), and a second striking device (44) inserted into the second end (52b) of the connector (52).

16. The fitness training assembly (40) of Claim 15, when dependent on any of Claims 10 to 14, wherein the first striking device (42) abuts the first locating surface (66) and the second striking device (44) abuts the second locating surface (68) when inserted therein, wherein the first and second locating surfaces (66, 68) are opposed to one another.

17. The fitness training assembly (40) of Claim 15 or Claim 16, when dependent on any of Claims 2 to 14, wherein the flexible material of the connector (52) is selected to permit bending of the fitness training assembly (40) along the longitudinal axis (L) under the weight of the first and second striking devices (42, 44).

18. The fitness training assembly (40) of Claim 17, wherein the extent of bending of the fitness training assembly (40) along the longitudinal axis (L) under the weight of the first and second striking devices (42, 44) is at least 5 degrees and preferably at least 10 degrees.

19. A fitness training device (10), in the form of a striking device, the fitness training device (10) comprising a handle portion (30) and a head portion (20), wherein the head portion (20) comprises a striking surface (26) and a cavity (70) that extends into the head portion (20) and behind the striking surface (26).

20. The fitness training device (10) of Claim 19, wherein the handle portion (30) extends from a handle surface (24), wherein the handle surface (24) is adjacent to the striking surface (26).

21. The fitness training device (10) of Claim 20, wherein the cavity (70) extends into the head portion (20) from a cavity surface (22), wherein the cavity surface (22) is adjacent to the striking surface (26) and opposed to the handle surface (24).

22. The fitness training device (10) of Claim 21 , wherein the cavity surface (26) is substantially planar and defines a base of the fitness training device (10).

23. The fitness training device (10) of any of Claims 19 to 22, wherein the head portion (20) is substantially frusto-spherical in shape.

24. The fitness training device (10) of any of Claims 19 to 23, wherein the cavity (70) is annular in shape.

25. The fitness training device (10) of any of Claims 19 to 24, wherein the cavity (70) comprises a first cavity portion and a second cavity portion.

26. The fitness training device (10) of Claim 19 or Claim 20, wherein the cavity (70) is housed entirely within the head portion (20) and does not comprise any external opening onto the cavity surface (22).

27. The fitness training device of any of Claims 19 to 26, including a retaining bore (35) which passes through the handle portion (30) and the head portion (20) to define a channel for receiving a fixing member (37) to provide a mechanical connection between the head portion (20) and the handle portion (30).

28. The fitness training device (10) as claimed in 27, wherein the retaining bore is a blind bore (35) which extends perpendicular to the longitudinal axis of the handle portion (30).

29. A fitness training assembly (40), comprising a first fitness training device (42) and a second fitness training device (44), both of which accord to any of Claims 19 to 26, and a connector (52).

30. The fitness training assembly (40) as claimed in Claim 29, wherein in use the first fitness training device (42) is inserted into a first end (52a) of the connector (52) and the second fitness training device (44) is inserted into a second end (52b) of the connector (52), the second end (52b) being opposed to the first end (52a).