Abstract:
An exercise device is suitable for progressively strengthening the intrinsic muscle groups of a limb extremity and the associated limbs of a user. The device has a base unit and a gripping surface. The gripping surface can be gripped by at least one of the digits of the limb extremity of the user. The exercise device further includes a system for applying resistance. The gripping surface is configured to adapt to fit the shape of the digits of the limb extremity of the user.

Description:
FIELD OF THE INVENTION 
     The invention relates to an exercise device suitable for progressively strengthening the intrinsic muscle groups of a limb extremity and the associated limb of a user, the device comprising a base unit, a gripping surface configured to be gripped by at least one of the digits of the limb extremity of said user and a resistence means. 
     BACKGROUND TO THE INVENTION 
     At present, there are no adequate resistant training facilities to train and progressively strengthen the intrinsic muscle groups of the foot and/or hand and the associated lower limbs through resistance training. In particular, it is important to develop and strengthen the muscles in the foot and the lower leg from an early age as developing these muscles will have a positive effect on a person&#39;s health and performance in many sports. However, from an early age, a lack of gripping, climbing and a lack of bare foot activities worsens the condition of the muscles groups, preventing the muscles from working efficiently and therefore weakening the feet. This problem worsens as a person grows older and can lead to many health problems through the lower joints up to the neck and back and can also have a detrimental effect on a person&#39;s balance. Therefore, it is advantageous to have a resistance training facility which progressively exercises the required muscle groups of the foot and lower leg from an early age to prevent such health problems. 
     Furthermore, such a resistance training facility is required for rehabilitation purposes to treat many injuries of the intrinsic muscle groups of the foot and lower leg, including metatarsal injuries, therefore enabling a speedy recovery from such injuries and keeping the muscle groups active and healthy. 
     It is also recognised that such a resistance training facility could potentially be used by an athlete wishing to improve their sport performance by increasing their balance, speed and jumping ability. 
     A previous method of treating injuries of the foot and/or lower leg involves the use of a towel and a dead weight. The injured person sits on a bench with their foot directly below their knee and their toes placed on one end of the towel. The dead weight is placed at the second end of the towel and the person grips the towel with their toes and drags the dead weight towards them. 
     A further method of treating the injuries of the foot and/or lower leg involves the injured person picking up marbles with the toes of their injured foot by gripping the marbles between the joints of the toes. 
     Although such methods are adequate for rebuilding the strength in the foot and lower leg, they cannot be used to progressively strengthen the muscle groups in the foot and lower leg therefore, strengthening the muscle groups against further injuries. Furthermore, such exercises do not allow for eccentric training: training in which the muscles are contracting whilst lengthening, as the toes are gradually returned to their starting position under resistance. 
     U.S. Pat. No. 4,461,472 (Martinez) discloses an exercise device suitable for exercising the metatarsal arch after a metatarsal injury has occurred. The exercise device comprises a housing and a sliding device which is guided by a guiding rod and is spring loaded against the housing, producing resistance against the flexing of the metatarsal arch. 
     The problems with exercise device of U.S. Pat. No. 4,461,472 is that the gripping bar is straight and so the exercise device can only effectively train the big toe and possibly the adjacent second toe. None of the other toes will fit over the gripping bar due to the natural curvature of the toe joints of the user. Therefore, a number of the important muscle groups in the foot and lower leg are not trained by the device. Furthermore, as the sliding device is moved relative to resistance produced by a spring attached to the guiding rod, it is not possible to progressively train the foot and lower leg as is it not possible to increase or decrease the spring resistance and hence the resistance against the flexing of the metatarsal arch. Further, a build up of friction may occur as the sliding base is pushed backwards and forwards against the spring resistance which is detrimental to the operation of the device. 
     An alternative device is disclosed in U.S. Pat. No. 4,577,861 (Bangerter) which describes an exercise machine capable of progressively strengthening the muscles of the fingers and/or toes and associated limbs. This machine comprises a hinged platform attached to a support member upon which the user of the machine places their hand or foot such that their fingers or toes are disposed on the platform. The hinged platform is linked up to a weight stack carrying a load which can be increased or decreased to progressively train the muscles. The platform is pressed down by the fingers or toes against the resistance of the weight stack, thereby flexing the muscles in the hand or foot and the associated limb. 
     The problem with the exercise machine disclosed in U.S. Pat. No. 4,577,861 is that the joint between the hinged platform and support member is straight, whereas the proximal joints of the fingers or toes of the user have a curved arrangement. Therefore, any proximal joints which do not line up with the joint of the machine will not contribute to the exercise and so the associated muscles will not be trained. 
     Furthermore, when all of the digits of the hand or foot are placed on the hinged platform, many of the proximal joints be located in front of the joint and hence pivot of the machine. Therefore, the proximal joints will not be aligned with the joint of the machine, causing a build up of friction as the digits scrap backwards on the hinged platform, when the platform is pressed down, and scrap forwards as the platform returns to its starting position. This also prevents a number of the muscle groups of the foot or hand and the associated limbs from being effectively trained by this machine. 
     The inventor has sought to provide an exercise device which progressively trains all of the intrinsic muscle groups of the foot and/or hand and associated limbs, which may be employed to prevent health problems, overcome sport injuries and improve performance in sport 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a exercise device which progressively trains all of the intrinsic muscles of a limb extremity and the associated limbs. 
     The invention achieves this objective by provision of an exercise device suitable for progressively strengthening the intrinsic muscle groups of a limb extremity and the associated limbs of a user, said device comprising: 
     a base unit; 
     a gripping surface configured to be gripped by at least one of the digits of said limb extremity of said user; and 
     a resistance means; 
     wherein said gripping surface is configured to adapt to fit the shape of said at least one of the digits of said limb extremity of said user. 
     By limb extremity it is meant the foot or hand of the user. The associated limb will be the leg or arm to which the foot or hand is attached. 
     The gripping surface of the exercise device of the present invention fits to the shape of at least one of the digits of the limb extremity of the user by adapting to match the size and distribution of the at least one digit. It is known that the distribution of the digits of a limb extremity is curved and that the curvature of the distribution of digits varies in one person to the next. Therefore, the exercise device of the present invention provides a means for exercising all of the digits of the user regardless of the size and distribution of their digits, to ensure that all of the intrinsic muscle groups of the limb extremity and associated limb are worked and progressively trained by the exercise device. 
     The adaptable gripping surface allows for the contribution of all of the toes or fingers to the exercise, therefore utilising all of the muscle groups of the limb extremity and associated limb. For example, the important intrinsic muscle groups of the foot and lower leg which may be worked by the exercise device of the present invention includes:
         The Flexor Hallucis Longus which runs down the calf of the lower leg to the big toe via the inside of the ankle;   The Flexor Digitoram Longus which runs down the back of the calf to all toes via the inside of the ankle;   The Flexor Digitoram Brevis which runs from the heel of the foot to the toes; and   The Flexor Hallucis Brevis which runs from the heel of the foot to the big toe.       

     The exercise device further allows the user to work the transverse arch and lateral arch of the outside of the foot as well as the arch on the instep of the foot. 
     The adaptable gripping surface design allows for the personalisation of the shape of the gripping surface such that all users can gain maximum results when using the exercise device of the present invention. 
     Preferably, the resistance means is capable of varying the resistance force provided to said exercise device. 
     The exercise device of the present invention will enable the user to strengthen the intrinsic muscles of the limb extremity and associated limb progressively by enabling the user to vary the resistance force acting on the device as the fingers or toes become stronger. Variation of the resistance means also enables the resistance to be adapted to the individual strength of the user, therefore enabling the same exercise device to be used by a person who has recently suffered a muscle injury or a person wishing to improve their performance in sports. 
     In a preferred embodiment of the present invention, the gripping surface comprises a plurality of protrusions extending from said gripping surface; and 
     movement of each of said plurality of protrusions is independent of the movement of each adjacent protrusion. 
     Alternatively, the gripping surface may comprise a plurality of recessed sections extending into said gripping surface; and 
     movement of each of said plurality of recessed sections is independent of the movement of each adjacent recessed sections. 
     In a further alternative embodiment of the present invention, the gripping surface is in the form of a detachable bar, said detachable bar being interchangeable with another detachable bar to adapt said gripping surface to fit the shape of said at least one of the digits of said limb extremity of said user. 
     Preferably, the exercise device further comprises a moveable portion configured to act against said resistance means. 
     In a first preferred embodiment of the invention, the moveable portion is located within a recess of said base unit; said moveable portion being configured to move longitudinally within said recess. 
     In this embodiment, the moveable portion comprises a platform and at least one roller element; 
     said at least one roller element being located within said recess of said base unit; and 
     said platform being disposed upon said at least one roller element. 
     Preferably, the gripping surface is disposed upon the upper surface of said platform and the platform is connected to said resistance means. 
     Roller elements are employed in this first preferred embodiment of the invention as they will reduce the build up of friction as the platform of the removeable portion moves forward and backwards by application of force from the digits of the user, against the resistance means. It further allows smooth movement of the platform from a relaxed to a tensed position, therefore enabling the exercise device to be used effectively for extended periods of time. 
     In a second preferred embodiment of the present invention, the moveable portion extends from a first end of said base unit. 
     In this embodiment, the moveable portion comprises a platform and an inclined frame; 
     said platform being slidably mounted upon said inclined frame. 
     Preferably, the inclined frame is pivotably connected at said first end of said base unit to allow downward and upward movement of said moveable portion. 
     Furthermore it is preferable that the gripping surface is disposed upon said platform and the inclined frame is connected to said resistance means. 
     The provision of a platform which is slideably mounted on the inclined frame of the moveable portion enables the digits of the user the freedom of movement as the inclined platform moves downwards and upwards against the resistance means. This is advantageous as if the digits were held stationary, there would be a build up of friction between the digits and the platform. Therefore, the arrangement of the platform and inclined frame of the moveable portion of the second preferred embodiment enhances the useability of the exercise device of the present invention. 
     Preferably the exercise device further comprises an adjustable heel support means. 
     A heel support can be adjusted to secure variable foot sizes to the device ensuring correct technique and preventing injury. The provision of the heel support prevents the user of the device from performing “cheat movements” wherein the user of the device effects movement of the moveable portion against the resistance means by using their whole leg rather than the digits of their limb extremity as the exercise device requires. In this way, the user would not be working the required muscles of the limb extremity and associated limb, therefore rendering the exercise device ineffective. The heel support prevents occurrence of such “cheat movements”. 
     The resistance means may comprise a pulley system configured to be attached to an external weight stack or alternatively, it may comprise a pulley system configured to be attached to an internal elastic resistance means, said internal elastic resistance means being disposed within said base unit. 
     The pulley system employed in either of the resistance means described above may be identical, therefore allowing the exercise device to be used with either an external weight stack or an internal elastic resistance means. Furthermore, when the pulley system is used with an external weight stack, the arrangement of the pulley system allows the exercise device to be fitted to any existing pulley weight stack in a gym. 
     In a specific embodiment of the present invention, the platform of said moveable portion comprises an inner shell and an outer shell; 
     said outer shell comprising a recessed portion in which said inner shell is disposed; and 
     said inner shell being capable of lateral movement within said recessed portion of said outer shell. 
     Preferably the platform further comprises a resilient means configured to oppose the lateral movement of said inner shell within said recessed portion of said outer shell. 
     The provision of a platform comprising an inner shell and an outer shell, the inner shell being capable of lateral movement opposing resilient means, allows the exercise device of the present invention to directly work the abductors and adductors of the limb extremity. The working of such muscle groups effectively stabilises the limb extremity in the sideward direction. This is particularly important when the device is used to exercise the foot of a user as it heavily influences the functioning of the foot and stabilises movement and balance thereof. 
     In a preferred embodiment of the present invention, the moveable portion comprises a spotting means configured to allow the user of said exercise device to assist the movement of said moveable portion against said resistance means. 
     The provision of a spotting means in the exercise device of the present invention enables the user to assist the movement of the moveable base against the resistance means, therefore providing a number of different elements of training for the use of the device. In particular, the spotting means can enable the user of the exercise device to use a greater resistance force by enabling the limb extremity to reach a tensed position aided by the spotting means, slowly relieve the tension in the spotting means and then hold the limb extremity in the tense position. This teaches the muscle to hold tension more effectively. 
     Alternatively, when the spotting means has assisted the limb extremity to reach the tensed position against a greater resistance, the user may then release the tension slowly with the limb extremity. 
     Furthermore, as it has been identified that the limb extremities are not accustomed to such exercise, the spotting means will enable the limb extremity to reach a fully curled position which could not be reached by use of the muscles in the lower extremity alone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which: 
         FIG. 1  shows a top perspective view of the exercise device in accordance with a first embodiment of the present invention. 
         FIG. 2  shows the exploded top perspective view of the exercise device of  FIG. 1 ; 
         FIG. 3   a  shows a cross-sectional view of the exercise device of  FIG. 1  in a relaxed position; 
         FIG. 3   b  shows a cross-sectional view of the exercise device of  FIG. 1  in a tensed position. 
         FIG. 4  shows a top view of a gripping surface suitable for use in the exercise device of the present invention; 
         FIG. 5  shows a perspective side view of a protrusion suitable for use in the exercise device of the present invention; 
         FIGS. 6   a  to  6   d  show a cross-sectional view of the moveable portion of the exercise device of the present invention in position under a recessed portion of the base unit, as the protrusion of the gripping surface is adjusted to fit the digit of the user; 
         FIG. 7  shows a top perspective view of a moveable portion in accordance with a second embodiment of the present invention. 
         FIG. 8  shows a cross-sectional view of the moveable portion of  FIG. 7 ; 
         FIG. 9  shows the top perspective view of an exercise device in accordance with a second embodiment of the present invention; 
         FIG. 10   a  shows a side view of the exercise device in accordance with a third embodiment of the present invention in a relaxed position; 
         FIG. 10   b  shows a side view of the exercise device of  FIG. 10   a  in a tensed position; and 
         FIG. 11  shows a top perspective view of the moveable portion of the exercise device of  FIG. 10   a.    
     
    
    
     DETAILED DESCRIPTION 
     There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description. 
     With reference to  FIG. 1  herein, there is shown an exercise device  101  in accordance with a first embodiment of the present invention. Exercise device  101  comprises a base unit  103 , a gripping surface  105 , a pulley system  107  and a heel support  109 . 
     Base unit  103  is in the form of a rectangular box having an upper shell  111  and a lower shell  113 . Lower shell  113  forms the base portion and four side walls of the rectangular box shape of the base unit  103 . Lower shell  113  comprises an aperture  115  which is located on the rear lateral side wall thereof. Lower shell  113  also comprises a non-slip material such as rubber, which is attached to the underside of the lower shell  113  of the base unit  103  to prevent movement of the exercise device  101  when in use. 
     Upper shell  111  covers the uppermost edges of the lower shell  113 , having side portions  114  which extend down a portion of the longitudinal side walls of the lower shell  113 . The uppermost surface  116  of upper shell  111  comprises a cushioning means (not shown) to cover a portion of the surface which will be in contact with the foot of the user of the exercise device  101 . Cushioning means may be formed of foam covered with leather or a resilient material such as rubber to provide comfort to the user during use of the exercise device  101 . 
     Gripping surface  115  is disposed at the uppermost surface  116  of the upper shell  111  of the base unit  103 . Gripping surface  105  comprises fifteen protrusions  117  extending upwards therefrom and fifteen corresponding tracks  119 . Corresponding tracks  119  extend in the longitudinal direction over gripping surface  105  and have a plurality of engaging means which protrude slightly from the gripping surface  105 . Protrusions  117  are moveable along the corresponding tracks  119  and are fixed in the required position by engagement with the engaging means of the corresponding tracks  119 . Protrusions  117  may be repositioned by the user of the exercise device  101  so as to fit the size and distribution of their toes. 
     In an alternative embodiment of the present invention, protrusions  117  are replaced with a plurality of recessed sections which are moveable about corresponding tracks  119  to provide the adaptable gripping surface  105 . 
     Pulley system  107  comprises an upper pulley  121  and a lower pulley  123  held in position by a stabilising structure  125 . Pulley system  107  further comprises a cable (not shown) which passes over the lower pulley  123 , then over the upper pulley  121  and is connected to a variable resistance device (not shown), for example an external weight stack or an internal elastic resistance. 
     Pulley system  107  is located on the uppermost surface  116  of the upper shell  111  of the base unit  103  with lower pulley  123  being positioned over a slot  127  in the uppermost surface  116 . In this way, the cable (not shown) of the pulley system  107  is fed over the lower pulley  123  from the interior of the base unit  103 , where it is connected to a moveable portion (not shown). 
     Heel support  109  has a curved shape in order to fit the curve of the heel of a user of the exercise device  101 . Heel support  109  comprises two lugs  129  positioned at either side of heel support  109 , extending downwards thereform. Heel support  109  is located on the uppermost surface  116  of the upper shell  111  of the base unit  103 . 
     Uppermost surface  116  of the upper shell  111  of the base unit  103  comprises a series of holes  131  and a branched track  133  extending parallel to the series of holes  131  in a longitudinal direction along the uppermost surface  116 . The series of holes  131  are aligned with the branches of the branched track  133 . The series of holes  131  and branched track  133  are configured to receive the downwardly extending lugs  129  of the heel support  109  to secure the heel support  109  in position and provide a mechanism for adjusting the heel support  109  to fit any size foot of the user of the exercise device  101 . 
     In use, the user unclips the right-hand lug  129  from the hole  131  in which it is located, moves the left-hand lug (not shown) out of the branch and along the track of the branched track  133  and re-positions the heel support  109  by first inserting the left-hand lug in the required branch of the branched track  133  and then inserting the right-hand lug  129  into the corresponding hole  131 . In this way, the user can position the heel support  109  to fit the size of their foot, such that their toes fit over the protrusions  117  of the gripping surface  105 . 
     With reference to  FIG. 2  herein there is shown an exploded view of the exercise device  101  of  FIG. 1  in which the heel support  109 , the protrusions  117  of the gripping surface  105  and the pulleys  121  and  123  of the pulley system  107  have been removed. Accordingly, many of the features of  FIG. 2  are identical to those of  FIG. 1  and so will not be discussed in relation to  FIG. 2  so as not to repeat the description. 
     Exercise device  101  further comprises a moveable portion  201  comprising a platform  203  and five roller elements  205 . Moveable portion  201  is disposed with a recessed area  211  of the base unit  203 . 
     Platform  203  is rectangular having the gripping surface  105  disposed on the uppermost surface thereof. Platform  203  comprises two attachment means  207  and  209  in the form of two eyelets, located centrally on the front and rear edge of the platform  203 . Attachment means  207  is fitted with a cable (not shown) which feeds through slot  127  to the pulley system  107  which is attached to a resistance device such as an external weight stack or an internal elastic resistance. Attachment means  209  is fitted with a second cable (not shown) which runs out of the lower shell  113  of the base unit  103  via aperture  115 . The second cable is attached to a handle which allows the user of the exercise device  101  to “spot” the movement of the moveable portion  201  against the resistance means. By “spot” it is meant that the user of the exercise device  101  can use the handle to which the second cable is attached to assist the movement of the platform  203  of the moveable portion  201  against the resistance means, therefore enabling the foot to move the platform  203  against a greater resistance force than would be possible by the strength of their foot alone. 
     Roller elements  205  of the moveable portion  201  are disposed within the recessed area  211  of the lower shell  113  of the base unit  103 . Roller elements  205  are held in position within the recessed area  211  via a series of grooves  213 , disposed on the longitudinal side walls of the lower shell  113 . The grooves  213  on either side wall of the lower shell  113  are aligned such that when the roller elements  205  are in position within the recessed portion  211 , they are parallel to one another and to the lateral side walls of the lower shell  113 . 
     Roller elements  205  are cylindrical and are capable of rotation within the grooves  213  of the lower shell  113  of the base unit  103 . Platform  201  is disposed upon the roller elements  205  such that the platform  203  rolls forwards and backwards on the roller elements  205  in use. 
     Upper shell  111  of the base unit  103  comprises a rectangular cut-away section  215 . When the upper shell  111  of the base unit  103  is in position over the lower shell  113  (as in  FIG. 1 ) and the exercise device  101  is not in use, the platform  203  of the moveable portion  201  is positioned in alignment with and beneath the cut-away section  215  of the upper shell  111 . The protrusions (not shown) of the gripping surface  105  extend upwards through the cut-away portion  215 , sufficiently high enough to allow the user of the exercise device  101  to successfully curl their toes around the protrusions. Accordingly, the rectangular cut-away portion  215  is of substantially similar dimensions to the platform  203  of the moveable portion  201 . 
       FIGS. 3   a  and  3   b  shows the exercise device  101  of  FIGS. 1 and 2  in a first relaxed position and a second tensed position respectively. The exercise device  101  of  FIG. 1  is shown in cross-section with the heel support and the cable linking the moveable portion  201  to the pulley system  107  of the resistance means removed. 
     When the exercise device  101  of  FIG. 1  is assembled, the roller elements  205  of the moveable portion  201  are disposed within the recessed area  211  of the lower shell  113  of the base unit  103  and are rotatable about a fixed position. Platform  203  is located upon the roller elements  205  beneath the rectangular cut-away section  215  of the upper shell  111  of the base unit  103 , such that the protrusions  117  of the gripping surface  105  extend upwardly through the cut-away section  215 . 
     A variable resistance device such as an external weight stack or an internal elastic resistance is connected to the platform  203  of the moveable portion  201  via pulley system  107 . The cable (not shown) of the pulley system  107  is secured to the attachment means  207  of the platform  203 . The cable then exits the recessed area  211  of the lower shell  113  of the base unit  103  via slot  127  and passes over lower pulley  123  and upper pulley  121  of the pulley system  107  such that the path of the cable forms an “S” shape. From the upper pulley  121 , the cable is attached to the resistance device. 
     If the exercise device  101  is to be used with an external weight stack, once the cable has passed through pulley system  107 , it may either be connected via a ring clip to an external resistance cable which is attached to the external weight stack, or connected directly to the external weight stack. The load of the external weight stack may be varied to vary the resistance force as required by the user of the exercise device. 
     If the exercise device  101  is to be used with an internal elastic resistance, the internal elastic resistance may comprise a plurality of elastic resistance cords. These elastic cords are fixed within a box housing which is extendable and retractable, allowing freedom of movement to the cords. The box housing is designed to be attached to and detached from the device  101 . In use, the box housing is connected to the front portion of base unit  203  via pegs. The front surface of the box housing is connected to the platform  203  of the moveable portion  201  via pulley system  107  and the attachment means  207 . When the platform  203  is subjected to a pulling force via the gripping surface  105 , resulting in movement of the platform  203  towards the rear of the base unit  103 , the box housing extends causing the elastic cords to stretch, thus supplying elastic resistance to the rear displacement. When the pulling force is removed the elastic cords retract and the platform  203  returns to its relaxed position. The elastic resistance cords may be tightened or loosened to vary the elastic resistance force. 
     A further cable is attached to the second attachment means  209  of the platform  203  of the moveable portion  201 , which exits the recessed area  211  of the lower shell  113  via aperture  115 . The second cable may be used to “spot” or assist the motion of the platform  203  against the resistance means. 
     In preparation for use of the exercise device, the user of the exercise device  101  adjusts the protrusions  117  of the gripping surface  105  by moving them along the corresponding tracks  119  so that the distribution of the protrusions  117  on the gripping surface  115  matches the shape of the toes and the curvature of the joints of the user of the exercise device  101 . The heel support (not shown) which is disposed upon the uppermost surface  116  of the upper shell  111  of the base unit  103  may be adjusted to fit the foot size of the user, such that the toe joints of the user are located at the base of the protrusions  117  of the gripping surface  105  and their toes curled over the protrusions  117 . In this way, the foot is supported by the heel support, ensuring that the user of the exercise device  101  uses the correct technique and also preventing any injuries from occuring. The user of the exercise device  101  then selects the type of resistance device and resistance force provided by the resistance device. 
     The user of the exercise device  101  may then position their foot on the device  101  such that the heel rests against the heel support and the toes curl over the protrusions  117  of the gripping surface  105 , gripping the platform  203  of the moveable portion  201 . In use, the user pulls the platform  203  of the moveable portion  201  towards their heel with their toes, thereby effecting movement of the platform  203  against the resistance provided by the resistance means, as shown in  FIG. 3   b . As the platform  203  of the moveable portion  201  is pulled towards the heel of the user, the platform  203  is drawn over the roller elements  205  of the moveable means  201 . Rotation of the roller elements  205  effects smooth movement of the platform  203  from a relaxed position (as illustrated in  FIG. 3   a ) to a tensed position (as illustrated in  FIG. 3   b ). 
     As the platform  203  of the moveable portion  201  is forced rearwards by the strength of the user&#39;s foot, the cable (not shown) connecting the platform  203  to a resistance device via the pulley system  107  and attachment means  207 , is drawn into the recessed portion  211  of the lower shell  113  of the base unit  103 . The cable moves against the force of the resistance device and hence provides the resistance to the movement of the platform  203 . As the cable is drawn over the lower pulley  123  and the upper pulley  121  of the pulley system  107 , the upper and lower pulleys  121  and  123 , rotate relative to axes  301  and  303 , which are fixed to the stabilising structure  125  of the pulley system  107 . In this way, smooth movement of the platform  203  of the moveable portion  201  against the resistance force is effected. 
     The user of the exercise device  101  has the option of retaining the platform  203  of the moveable portion  201  in a tensed position (as in  FIG. 3   b ) for a certain period of time or alternatively, once the user has reached the fully tensed position, they can release a tension in the cable straightaway, returning the platform  203  to the relaxed position illustrated in  FIG. 3   a.    
     In order to increase the strength of the toes, the user repeats the above action a number of times. As the muscles of the foot and lower leg become stronger, the user can increase the resistance force acting on the platform  203 , in order to progressively train the muscles of the foot and lower leg. 
     Exercise device  101  may further comprise shock absorbing springs or air pressure valves located within the recessed area  211  of the lower shell  113  of the base unit  103 . The shock absorbing springs or air pressure valves provide cushioning of the platform  203  of the moveable portion  201  as it moves from a relaxed position to a tensed position and back to the relaxed position. This further enables smooth movement of the platform  203  of the moveable portion  201 . 
     With reference to  FIG. 4  herein there is shown a gripping surface  401  which may be used in the exercise device of the present invention. Gripping surface  401  comprises fifteen protrusions  403  and fifteen corresponding tracks  405 . 
     Protrusions  403  are substantially square shaped when viewed from above and extend upwardly from the uppermost surface  407  of the platform of the moveable portion on which the gripping surface  401  is disposed. Protrusions  403  move along the corresponding track  405  so as to be adjustable to fit the size of the toes and curvature of the toe joints of the user of the exercise device. 
     Corresponding tracks  405  comprises a central channel  409  and a plurality of engaging means having a plurality of teeth  411  and a plurality of voids  413 . The plurality of teeth  411  are disposed equidistant from one another on either side of the central channel  409 , with the plurality of voids  413  located between each pair of adjacent teeth  411 . The plurality of teeth  411  on each side of the central channel  409  of the corresponding track  405  are aligned. Teeth  411  extend slightly from the uppermost surface  407  of the platform, to about a quarter of the height of the protrusions  403 . 
     In use, the user of the exercise device upon which the gripping surface  401  is disposed moves the protrusions  403  along the corresponding tracks  405  in order to reposition the protrusion  403  to fit the shape of their toes. When the position of the protrusions  403  have been selected, they are secured in place by engagement with the plurality of teeth  411  and the plurality of voids  413  of the corresponding track  405 . 
     The central channel  409  of the corresponding track  405  extends down through the uppermost surface  407  of the platform of the moveable portion. 
     With reference to  FIG. 5   a  herein there is shown a protrusion  501  suitable for use with the gripping surface  401  of  FIG. 4 . Protrusion  501  comprises a body portion  503 , two engager portions  505  and a rod member  507 . 
     Body portion  503  of protrusion  501  has a three-dimensional rectangular shape having one angled edge  509  and one curved edge  511  positioned at the upper section of the body portion  503 . The angled edge  509  of the upper section of the body portion  503  is located at the front edge of the protrusion  501 . The curved edge  511  is located at the rear edge of the protrusion  501  and directs curling of the toe over the body portion  503  of the protrusion  501 . 
     Engager portions  505  extend from the lower surface of the body portion  503  of the protrusion  501  on opposite sides thereof. Engager portions  505  are configured to secure the protrusion  501  in place on the corresponding track of the gripping surface by engagement with the teeth and voids located on either side of the corresponding track. The lower surfaces of engager portions  505  are curved in order to assist the movement of the protrusion  501  from one void over the adjacent teeth towards an alternative void. 
     Rod member  507  also extends from the lower surface of the body portion  503  of the protrusion  501  and is located between the engager portions  505 . Rod member  507  comprises a resilient member  513  surrounding the rod member  507 . Resilient member  513  has an upper flange  515  and a lower flange which are configured to restrict the movement of the resilient member  513 , preventing it from moving up the rod member  507  and entering the space between the engager portions  505 . Rod member  507  further comprises a hexagonal nut  519  which retains the resilient member  513  in place on the rod member  507 . 
     With reference to  FIGS. 6   a ,  6   b ,  6   c  and  6   d  herein, there is shown the protrusion  501  of  FIG. 5  in use in an exercise device of the present invention. 
       FIGS. 6   a  to  6   d  show the protrusion  501  of  FIG. 5  disposed on a gripping surface  601  comprising a corresponding track having a plurality of evenly spaced teeth  603  and a plurality of evenly spaced voids  605  disposed between adjacent teeth  603 . Gripping surface  601  is disposed upon a platform  607  of a moveable portion, the platform comprising a recessed portion  609 . The moveable portion further comprises a number of roller elements  611  upon which the platform  607  is disposed. 
     As in the previous embodiments, moveable portion is located in the recessed area of the base unit of the exercise device, such that platform  607  is located beneath a cut away section  615  in the upper shell  613  of the base unit in a relaxed position. Protrusion  501  extends upwardly from the cut-away section  615  in the upper shell  513  of the base unit. 
     When in position, protrusion  501  is situated on the corresponding tracks of the gripping surface  601  with its engager portions  505  located between adjacent teeth  603 , in the voids  605  of the corresponding track. The rod portion  507  of the protrusion  501  extends from the lower section of the body portion of the protrusion  501  into the central channel (not shown) of the corresponding track, which extends through the upper surface of the platform  607  into the recessed portion  609  thereof. The resilient member  513  surrounding the rod member  507  is located within the recessed portion  609  of the platform  607  and the upper flange  515  of the resilient member  513  retains the resilient means  513  within the recessed portion  609  of the platform  607 . 
     Resilient member  513  prevents the protrusion  501  from moving freely by securing the protrusion  501  on the corresponding track, preventing the engager portions  505  moving out of the voids  605  of the gripping surface  615  once in position. 
     In order to adjust the position of the protrusion  501  to fit the shape of the toes of the user of the exercise device, the use pulls the protrusion  501  upwards, compressing the resilient member  513 . This enables the engager portions  505  to move out of the voids  605  of the corresponding track of the gripping surface  601 , as shown in  FIG. 6   b . The user then pulls the protrusion  501  along the corresponding track, keeping the resilient member  513  compressed, to a position in line with the shape of their toes as in  FIG. 6   c . Once the user has chosen the correct positioning of the protrusion  501  to match the shape of their toes, they release the protrusion  501 , therefore relieving the tension in the resilient member  513  and allowing it to return to its relaxed state. Relaxation of the resilient member  513  draws the engager members  505  of the protrusion  501  into the voids  605  of the corresponding track, thereby securing the protrusion  501  in the required position. 
     Each protrusion is positioned in this way in order to adapt the gripping surface of the exercise device to fit the shape of the toes of the user. The exercise device will then ensure that all of the toes are exercised during use and so all of the intrinsic muscle groups of the foot and lower leg are progressively trained by the exercise device of the present invention. 
     Alternatively, the mechanism by which the protrusions  501  may be repositioned and secured about the gripping surface of the exercise device of the present invention may be by any suitable known means. For example, the resilient member may be located inside of the body portion of the protrusion and rather than having a rod member and engager portions extending from the lower section thereof, the body portion may be rounded at the lower section. Therefore, the protrusion will click and in and out of the voids of the corresponding track as the user of the device pulls them in an upward direction. The mechanism will also comprise a lever which raises the lower portion of the platform, thereby reducing the volume of the recessed portion of the platform and locking the protrusions into position. 
     With reference to  FIGS. 7 and 8  herein there is shown an alternative embodiment of the moveable portion  701  of an exercise device of the present invention. Moveable portion  701  comprises a platform  703  and roller elements  705 . Moveable portion  701  is located in the recessed area of the base unit of an exercise device of the present invention with the platform  703  located upon roller elements  705 , as in  FIG. 2 . Roller elements  705  are fitted into channels of the base unit, as in  FIG. 2 , to allow them to rotate relative to the base unit, in the channels. In this way, platform  703  moves in the longitudinal direction within the recessed area of the base unit, over roller elements  705  as they rotate about their fixed position. 
     Platform  703  comprises an inner shell  707 , an outer shell  709  and a plurality of resilient members  711 . 
     Inner shell  707  comprises a gripping surface  713  disposed on the uppermost surface thereof. Gripping surface  713  comprises fifteen protrusions  715  and corresponding tracks  717  comprising a plurality of teeth and voids. Protrusions  715  extend from the uppermost surface of inner shell  707  and are capable of movement along the corresponding tracks  717 , such that the user of the exercise device can position the protrusions  715 , to fit the shape of their toes. Protrusions  715  may be secured in and moveable along the corresponding track  717  in the same way as described in  FIGS. 6   a  to  6   d.    
     Outer shell  709  is formed of a rectangular box shape having a central recessed portion  719 . Inner shell  707  is disposed upon a series of smaller roller elements  721  within the recessed portion  719  of the outer shell  709 . Inner portion  707  is also of a rectangular box shape and is of equal length to the recessed portion  719  of the outer shell  709  in the longitudinal direction. However, the recessed portion  719  of the outer shell  709  has a greater lateral length than the inner shell  707 . 
     Inner shell  707  is located centrally within the recessed portion  719  of the outer shell  707 . Eight resilient members  711  are located in the free space of the recessed portion  719  of the outer shell  709 , evenly distributed on either side of the inner shell  707 . Resilient members  711  may be in the form of a plurality of rubber springs which may be compressed when the inner shell  707  is moved from side to side. 
     In preparation for use, the user of the exercise device in which the moveable portion  701  is disposed adjusts the protrusions  715  of the gripping surface  713  to fit the shape of their toes, as described in relation to the previous embodiments. When the exercise device has been correctly adjusted to the requirements of the user, their foot has been positioned on the base unit by the heel support (not shown) and the type and strength of the resistance device selected, the user can commence using the exercise device. 
     In use, the user curls their toes around protrusion  715  of a gripping surface  713  and pull the platform  703  rearwards towards their heel, over roller elements  705 . Once the platform  703  is in a tensed position, the user may force the inner shell  707  of the platform  703  from side to side against the resistance of the resilient members  711 , in order to further train the intrinsic muscle groups of the foot and lower leg. In order to effect sidewards movement of the inner shell  707  of the platform  703 , the user may push their toes sidewards against adjacent protrusions  715  on the gripping surface  713 . As the inner shell  707  moves sideways within the recessed portion  719  of the outer shell  707 , small roller elements  721  rotate about a fixed position to allow the inner shell  707  to move smoothly from side to side. If the smaller roller element  721  were removed from this arrangement, movement of the inner shell  707  would be uneven and would experience friction as it scrapes against the lower surface of the recessed portion  719 . 
     In the alternative embodiment, the user of the exercise device in which the moveable portion  701  of  FIG. 7  is employed can carry out the lateral movement of the inner shell  707  within the recessed portion  719  of the outer shell  709  of the platform  703  whilst the platform:  703  is in a relaxed position, i.e. when the platform  703  is stationary. 
     Resistance members  711  may be tightening in order to increase the resistance to the lateral movement of the inner shell  707  within the recessed portion  719  of the outer shell  719 , in order to progressively train the muscles worked during this exercise. 
     In this embodiment, the outer shell  709  of the platform  703  cannot move in the lateral direction but only in the longitudinal direction against the force of resistance of the resistance means. 
     With reference to  FIG. 9  herein there is shown an alternative embodiment of the exercise device  901  of the present invention. Exercise device  901  comprises a base unit  903 , a gripping surface  905 , a pulley system  907  and a heel support  909 . 
     Base unit  903  is substantially rectangular shaped having raised portions  911  and  913  located at each end thereof. Heel support  909  is located in the first raised portion  911  and is adjustable via a ratchet means  915  located on the upper surface  917  of the base Unit  903 . Ratchet means  915  allows the heel support to be pushed forwards in order to be repositioned to meet the requirement of the user of the device  901 . Heel support  909  is moveable only in a forward direction on ratchet means  915 , therefore a lever  919  is provided which releases the heel support  909 , allowing it to return to its original position at the raised portion  911 . 
     In this embodiment, gripping surface  905  comprises a detachable bar  923  and is located on a moveable portion  921 . Moveable portion  921  comprises a platform  925  and roller elements  927 . Roller elements  927  are in the form of a plurality of ball bearings contained within a section of the internal portion of the base unit  903 . Platform  925  is positioned below a cutaway section  929  in the upper surface  917  of the base unit  903 . 
     Detachable bar  923  extends upwardly from the upper surface of the platform  925 . Detachable bar  923  is shaped to fit the shape of the toes of the user and is fixed onto the upper surface of the platform  925  via pegs (not shown) which are located on the underside of the detachable bar  923 . The pegs enable the detachable bar  923  to be clipped onto the upper surface of the platform  925  via receptive peg holes  931 . Detachable bar  923  is detachably mounted on the upper surface of platform  925 , such that if the bar positioned on the platform  925  does not correspond to the shape of the toes of the user, the user can remove the existing detachable bar  923  and replace it with a suitably shaped alternative detachable bar  923 . 
     In this embodiment, detachable bar  923  is connected to pulley system  907  via cables  933 ,  935  and  937  and attachment ring  949 . Pulley system  907  comprises a pulley  939  which is held in place by two stabilising arms  941  and  943  of the raised portion  913  of the base unit  903 . Pulley  939  is rotable relative to stabilising arms  941  and  943  as the cable  937  passing over the pulley  939  is pulled backwards and forwards. Pulley system  907  is connected to a variable resistance device (not shown) via cable  937 . 
     Base unit  903  is also provided with weight bearers  945  located near to the front portion of the base unit  903  which may be drawn from the internal portion of the base unit  903  when required. Weights (not shown) may be rested on weight bearers  945  of the exercise device  901  to prevent the exercise device  901  from lifting from the ground when the device  901  is used in conjunction with a large resistance force. 
     A gage  947  with markings is provided on the uppermost surface  917  of the base unit  903 , adjacent to the gripping surface  905  and the platform  925  in a relaxed position. The gage  947  allows for the range of motion to be visually assessed when the gripping surface  905  and platform  925  are drawn rearwards in use. 
     In preparation for use, the user of the exercise device  901  selects the appropriate detachable bar  923  to fit the shape of their toes and clips it into place on the upper surface of the platform  925  of the moveable means  921 . The user then adjusts the heel support  909  so that the heel support  909  supports their foot whilst their toes are curled over the detachable bar  923 . This is done by pushing the heel support  909  forward along ratchet means  915  until it clicks into the correct position. The user then selects the type and strength of the resistance device and connects it to the exercise device  901  via cable  937 . 
     Once the exercise device  901  has been correctly assembled for use, the user places the joints of their toes on the rear side of detachable bar  923  and curls their toes over the detachable bar  923 . The user then pulls the detachable bar  923  with their toes against the resistance means, back towards the heel of their foot. As the detachable bar  923  is pulled backwards, it draws the platform  925  of the moveable portion  921  backwards, sliding over the roller elements  927  which rotate, thereby allowing smooth movement of the platform  925  and the detachable bar  923 . The user may hold the weight in position for a period of time or slowly release the detachable bar  923 , thereby releasing the tension in the cable  937  and returning the exercise device  901  to a relaxed position. 
     In order to train the muscles of the foot and lower leg, the user repeats this action a number of times. As the muscles in the foot and lower leg become stronger, the resistance force can be increased in order to progressively train and therefore strengthen the muscle groups in the foot and lower leg. 
     With reference to  FIGS. 10   a  and  10   b  herein there is shown a third embodiment of the exercise device  1001  of the present invention. Exercise device  1001  comprises base unit  1003 , gripping surface  1005 , pulley system  1007  and heel support  1009 . 
     Base unit  1003  comprises a first raised portion  1011  located at the rear end of the base unit  1003  and a second raised portion  1013  located at the front end of the base unit  1003 . In these figures, a portion of the raised portion  1013  is illustrated by a dotted line to show the portion in cross section, in order for the features of the exercise device  1001  hidden by the portion of the raised portion  1013  to be visible. 
     Heel support  1009  extends from an upper surface  1015  of the base unit  1003  and is curved at the front side thereof. The curve of the heel support  1001  is configured to match the curve of the heel of the user&#39;s foot  1017 . Heel support  1009  is adjustable on said base unit so that it can fit any size foot of the user. The means by which the heel support  1009  is adjustable may be similar to the corresponding feature in either  FIG. 1  or  FIG. 9 . 
     Base unit  1003  further comprises a moveable portion  1019 . Moveable portion  1019  comprises a platform  1021  and an inclined frame  1023  and extends from the front end of base unit  1003 . Gripping surface  1005  is disposed upon the upper surface of platform  1021  of the moveable portion  1019 . Inclined frame  1023  of moveable means  1019  is pivotably mounted at the front end of the base unit  1003  and platform  1021  is slidably mounted on the inclined frame  1023 . 
     Inclined frame  1023  is connected via an attachment means  1025  to the pulley system  1007 . Pulley system  1007  comprises a cable  1027  and a pulley  1029 . Pulley  1029  is held in position by support members  1031  and  1033  of the raised portion  1013  of the base unit  1003  and is rotatable relative to the supporting members  1031  and  1035 . Pulley system  1007  is connected to a resistance device via cable  1027 . 
     In preparation for use, the user of the exercise device  1001  positions the heel support  1009  to fit the foot size  1017  of the user so that the toes  1037  of the user rest on the previously adapted gripping surface  1005  disposed on the platform  1021  of the moveable portion  1019 . Cable  1027  of the pulley system  1007  is attached to the selected type and strength of resistance device. 
     Once assembled, the user uses the strength in their toes to push the inclined frame  1023  of the moveable portion  1013  downwards. As the inclined frame  1023  is pushed downwards, the user grips the gripping surface  1005  by curling their toes  1037 , hence moves the platform  1021  along the inclined frame  1023  towards the heel of their foot  1017 , as shown in  FIG. 10   b . Downward movement of the inclined frame  1023  of the moveable means  1019  acts against the resistance force as the cable  1027  attached to the resistance device is drawn downwards over pulley  1029 . The user then slowly returns the inclined frame  1023  to its original position as illustrated in  FIG. 10   a . These actions will be repeated a number of times to train the muscles of the foot and lower leg. 
     As in the previous embodiment, the resistance force apparatus can be increased in order to progressively train the muscle groups of the foot  1017  and leg  1039  of the user by use of the exercise device of the present invention  1001 . 
     With reference to  FIG. 11  herein there is shown the moveable portion  1019  of the exercise device  1001  of  FIGS. 10   a  and  10   b . Moveable portion  1019  comprises platform  1021  and inclined platform  1023 . 
     Platform  1021  is slidably mounted on inclined frame  1023  and comprises gripping surface  1005  at the upper surface thereof. Gripping surface  1005  comprises a plurality of recessed portions  1101  configured to receive the toes of the user of the exercise device such that the toes may curl into the recessed portion  1101  and grip the platform  1021 . Gripping of the platform  1021  enables it to slide back and forth on the inclined frame  1023 . 
     Platform  1021  is removable mounted on the inclined frame  1023  such that the user can select a platform having the correct distribution, size and depth of the recessed portions  1101  of the gripping surface  1005  to fit the shape of their toes. In this embodiment, platform  1021  is capable of clipping onto the inclined frame  1023  of the moveable means  1019  such that if the user applies force to the platform  1021 , it can be unclipped. 
     Alternatively, gripping surface  1005  may comprise plurality of protrusions as in  FIG. 4 , which are moveable on corresponding tracks to fit the shape of the foot of the user of the device. 
     Inclined frame  1023  is cylindrical and forms a rectangular shape. Located at the uppermost and front side of the inclined frame  1023  is an attachment means  1025 . Attachment means  1025  is attached to a resistance device via a cable of a pulley system such that movement of the inclined frame  1023  of the moveable portion  1019  acts against the resistance force of the resistance device therefore training the muscles of the foot and lower leg. 
     In an alternative embodiment of the present invention, the gripping surface, disposed on the platform of the moveable portion, may comprise a plurality of looped cords that may be adjusted to fitted the shape, size and length of the digits of the user. In this embodiment, the looped cords are attached via the pulley system to the resistance device. In use, the user grips the looped cords with their digits and pulls the cords rearwards against the force of the resistance device. As the digits pull the cords rearwards, the platform on which the digits are located slides over the roller elements of the moveable portion to prevent a build up of friction. 
     Although the above embodiments have been described in relation to apparatus suitable for training the intrinsic muscle groups of the foot and lower leg, it should be understood that the apparatus may be re-designed in order to be used to progressively train the intrinsic muscle groups of the hand and lower arm.