Patent Publication Number: US-2012040803-A1

Title: Achilles stretching devices and methods performed therewith

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part patent application of co-pending U.S. patent application Ser. No. 12/750,754, filed Mar. 31, 2010, which claims the benefit of U.S. Provisional Application No. 61/164,975, filed Mar. 31, 2009. The contents of these patent applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to therapy and physical fitness equipment, and more particularly to devices capable of stretching the calf muscle-Achilles tendon unit. 
     The Achilles tendon connects the calf muscles to the heel of the foot. The calf muscles pull on the heel through the Achilles tendon, enabling propulsion of the human body through the foot for walking and jumping activities. The combined length of the calf muscles and Achilles tendon should be short enough to contract strongly and generate enough power for daily activities, and also permit sufficient stretching to allow about ten to twenty degrees of ankle dorsiflexion. If the calf muscles and Achilles tendon cannot stretch and allow ankle dorsiflexion to this extent, the midfoot and the forefoot see abnormal stresses leading to pain and conditions like plantar fasciitis, flat feet, posterior tibial tendon dysfunction, stress fracture, and arthritis. 
     The normal human foot is a dynamic structure that can function as a flexible unit capable of adapting to uneven support surfaces during weight bearing, as well as a rigid unit capable of forward propulsion through tightening of the calf muscles. The loosening and stiffening of the foot automatically occur as a result of locking and unlocking the midfoot during walking and running. The same mechanism can be used in a reverse fashion to lock the midfoot and stiffen the foot by maximally lifting the big toe (hallux) and its metatarsal bone away from the ground or the level of the fifth toe and its metatarsal bone (supination of the forefoot). One can also pronate the forefoot by elevating the fifth metatarsal relative to the first metatarsal, which results in unlocking the foot and stretching the arch of the foot. 
     The Achilles tendon can be stretched by daily activities and specific exercises that force the forefoot (toes and metatarsus) toward the leg. In adults, weight-bearing exercises are generally more useful for stretching the Achilles tendon, whereas in children stretching is typically best accomplished with the assistance of an adult. Dynamic splints that provide constant stretching of the tendon can be used by both adults and children. However, such devices achieve limited stretching of the Achilles tendon because stretching of the calf muscle-Achilles tendon unit is more effective if the foot acts as a rigid lever and transmits all the stretch to the Achilles. If the foot is not rigid, some of the stretching forces tend to stretch the arch of the foot and can create or worsen an existing flatfoot condition. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention provides therapeutic devices and methods suitable for stretching the Achilles tendon. The devices provide for supination of the forefoot to make the foot more rigid and allow better stretching of the calf muscle-Achilles unit. Furthermore, the devices provide support for the arch of the foot, reducing stretching forces that would tend to stretch the arch of the foot and create or worsen an existing flatfoot condition. 
     According to a first aspect of the invention, a therapeutic device is provided that comprises a wedge portion and a base portion. The wedge portion has oppositely-disposed heel and toe ends in a fore-aft direction of the wedge portion, oppositely-disposed inside-foot and outside-foot edges in a lateral direction of the wedge portion, and an upper surface delineated by the heel and toe ends and the inside-foot and outside-foot edges of the wedge portion. The upper surface of the wedge portion comprises a planar surface portion that lies in a wedge plane and an arcuate surface portion defined by a projection that extends out of the wedge plane. The wedge plane has a nonuniform elevation relative to the base portion as a result of the wedge portion having a fore-aft taper in the fore-aft direction and a lateral taper in the lateral direction, wherein the inside-foot edge has a higher elevation at the toe end than at the heel end and the outside-foot edge has a substantially constant elevation in the fore-aft direction. The fore-aft taper and the lateral taper are sufficient so that placement of a user&#39;s heel on the upper surface at the heel end and the user&#39;s toes on the upper surface at the toe end causes supination and locking of the foot and enables stretching of the Achilles complex. The projection extends from the inside-foot edge toward but not to the outside-foot edge in the lateral direction, and extends between but not to the toe and heel ends of the wedge portion. The arcuate surface portion of the projection has arcuate contours in both the lateral and fore-aft directions, and the arcuate contours of the arcuate surface portion define an apex that is at least ten millimeters to about forty millimeters from the wedge plane. 
     According to further aspects of the invention, the device can be configured as a freestanding structure, in other words, the device does not require any additional external structure to support the device or enable the device to perform its intended function of supination and locking of the foot during stretching of the Achilles complex. As such, the base portion is adapted for placement on a surface of a floor or ground and the wedge portion enables weight-bearing stretching of the Achilles complex. The device can also be configured as a shoe wherein the wedge portion causes weight-bearing stretching of the Achilles complex when the user walks and runs while wearing the shoe, or configured as a splint wherein the nonuniform elevation of the upper surface of the wedge portion relative to the base portion is a result of the splint twisting the wedge portion, or configured as an apparatus comprising at least one strap attached to the base portion so that a user can pull the wedge portion to cause stretching of the Achilles complex. 
     Other aspects of the invention include stretching techniques using the devices described above. In each case, the device is specifically configured for stretching the Achilles complex of one foot, yet can also be switched to the opposite foot to pronate that foot and stretch the arch of the foot, for example, as a therapeutic treatment for high arched feet. 
     A technical effect of the invention is the ability of the devices to achieve greater stretching of the calf muscle-Achilles tendon unit as a result of the devices causing supination and locking of the foot, which results in the foot acting as a rigid lever that transmits essentially all of a stretching motion to the Achilles tendon. In this manner, the effectiveness of the stretching technique is increased to promote the ability of the calf muscles and Achilles tendon to stretch and allow ankle dorsiflexion, thereby reducing abnormal stresses within the midfoot and forefoot. Furthermore, the projection minimizes if not avoids stretching of the arch of the foot, thereby avoiding the creation or worsening of a flatfoot condition. 
     Other aspects and advantages of this invention will be better appreciated from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are end and side views, respectively, of a freestanding Achilles tendon stretching device in accordance with a first embodiment of this invention. 
         FIG. 3  is a perspective view of a freestanding Achilles tendon stretching device in accordance with a second embodiment of this invention. 
         FIG. 4  is a side view of a freestanding Achilles tendon stretching device similar to  FIG. 3 , but with the addition of a rocker feature at its lower surface. 
         FIGS. 5 ,  6 ,  7  and  8  show the device of  FIG. 3  in combination with shoes ( FIGS. 5 and 6 ), a splint ( FIG. 7 ), and straps ( FIG. 8 ) in accordance with additional embodiments of the invention. 
         FIGS. 9 through 11  are various views of an Achilles tendon stretching device and its components in accordance with a third embodiment of this invention. 
         FIGS. 12 through 14  represent a perspective view and two side views of an Achilles tendon stretching device in accordance with a fourth embodiment of this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The Figures depict therapeutic devices that can be used to stretch the Achilles tendon in accordance with particular embodiments of the invention. For convenience, consistent reference numbers are used throughout the Figures to identify the same or functionally equivalent elements. Furthermore, to facilitate the description of the devices, the terms “fore,” “aft,” “side,” “upper,” “lower,” “right,” “left,” etc., will be used in reference to the perspective of a user during use of the devices, and therefore are relative terms and should not be otherwise interpreted as limitations to the construction of the devices or as limiting the scope of the invention. 
       FIGS. 1 and 2  represent a freestanding Achilles tendon stretching device  10  in accordance with a first embodiment of this invention. The device  10  is shown as having wedge portions  12  comprising a left wedge portion  12   a  and a right wedge portion  12   b , which are essentially mirror images of each other. The wedge portions  12  are shown coupled to each other through a base portion  14  that comprises two risers  14   a  and  14   b  located adjacent heel and toe ends  16  and  18 , respectively, of the wedge portions  12 . The heel and toe ends  16  and  18  are oppositely-disposed in the fore-aft direction of their respective wedge portions  12 . Each wedge portion  12  is further configured to have oppositely-disposed inside-foot and outside-foot edges  20  and  22  in a lateral direction of the wedge portion  12 , and an upper surface  24  delineated by the heel and toe ends  16  and  18  and the inside-foot and outside-foot edges  20  and  22 . 
     The upper surface  24  of each wedge portion  12  is shown to lie in a plane but have a nonuniform elevation relative to the base portion  16  as a result of the size and shape of the risers  14   a  and  14   b . In particular, the riser  14   a  adjacent the heel ends  16  of the wedge portions  12  is smaller than the riser  14   b  adjacent the toe ends  18  of the wedge portions  12 , causing the wedge portions  12  to taper in both the fore-aft and lateral directions relative to a surface  26  on which the base portion  14  is supported, such that the inside-foot edge  20  has an increasing elevation toward the toe end  18 , while the outside-foot edge  22  has a substantially constant elevation in the fore-aft direction. In addition, each wedge portion  12  has a nonconstant lateral width in the lateral direction as a result of the toe end  18  having a width that is greater than the width at the heel end  16 . For example, the lateral width of each wedge portion  12  can nominally conform to a typical difference in the width of a human foot at the toes and heel. For this purpose, each wedge portion  12  may be sized for a specific range of foot sizes. 
     According to a preferred aspect of the invention, the fore-aft and lateral tapers of the wedge portions  12  are sufficient so that placement of one&#39;s foot on one of the upper surfaces  24  of the wedge portions  12  causes supination and locking of the foot and enables stretching of the Achilles complex. As an example, the inside-foot edge  20  at the toe end  18  may be elevated about one to about four inches (about 2.5 to about 10 centimeters) above the outside-foot edge  22  as a result of the fore-aft and lateral tapers of each wedge portion  12 . As evident from  FIGS. 1 and 2 , the elevation of the inside-foot edge  20  relative to the outside-foot edge  22  can be achieved with the outside-foot edge  22  located at the same level as the surface  26  supporting the device  10 . Alternatively, it is foreseeable that the outside-foot edge  22  could be slightly elevated at the toe end  18  relative to the heel end  16 . 
     In use, an individual can utilize either or both wedge portions  12  of the device  10 . In either case, a user places his or her heel against the upper surface  24  at the heel end  16  of the wedge portion  12  and places his or her toes against the upper surface  24  at the toe end  18  of the wedge portion  12  to cause supination and locking of the foot and stretching of the Achilles complex. In the embodiment of  FIGS. 1 and 2 , in which the device  10  is resting on the support surface  26 , the user is able to shift his or her weight to the foot to cause weight-bearing stretching of the Achilles complex. Though shown as mirror images of each other to achieve a similar stretching effect for each foot, the fore-aft and lateral tapers of the wedge portions  12   a  and  12   b  could differ to achieve a different degree of stretching for the left and right feet. 
     While each wedge portion  12  is specifically configured for stretching the Achilles complex of either the right or left foot, each wedge portion  12  can also be used on the foot opposite the intended foot to pronate the opposite foot and stretch the arch of that foot, for example, as a therapeutic treatment for high arched feet. 
     Various materials can be used in the construction of the device  10  shown in  FIGS. 1 and 2 , including but not limited to plastic, rubber, metal and wood materials and combinations thereof. Though represented as an assembly of individual components, the device  10  could be produced as a unitary body, such as by a molding process that results in the device  10  being a solid body whose lower part defines the base portion  14  and whose upper part defines the wedge portions  12   a  and  12   b  and their surfaces  24 . The upper surface  24  of each wedge portion  12  can be defined by or covered by a slip-resistant material, or otherwise treated to have a slip-resistant surface texture (not shown). In addition or alternatively, the device  10  can be equipped with straps  28  or other means for individually securing the user&#39;s foot or feet to the wedge portions  12 . 
     The embodiments of  FIG. 3  through xx share similarities with the embodiment of  FIGS. 1 and 2 , and therefore the following discussion of the remaining embodiments will focus primarily on aspects of these embodiments that differ from the first embodiment in some notable or significant manner. Other aspects of the additional embodiments not discussed in any detail can be, in terms of structure, function, materials, etc., essentially as was described for the first embodiment. 
     In the embodiment of  FIGS. 3 through 8 , one wedge portion  12  is represented as being a separate freestanding body that, while capable of being a mirror image of a second wedge portion (not shown), is not coupled to a second wedge portion. Furthermore, the wedge portion  12  and base portion  14  of the device  10  are formed as a unitary body, and the nonuniform elevation of the upper surface  24  of the wedge portion  12  relative to the base portion  14  is the result of the wedge portion  12  having a nonuniform thickness defined by its fore-aft and lateral tapers. The wedge portion  12  of  FIGS. 3 through 8  is well suited for being formed by molding, preferably from a hard plastic or rubber material. Though not shown, the embodiment illustrated in  FIG. 3  can be secured to the foot with a strap similar to the embodiment of  FIGS. 1 and 2 , or secured in any other suitable manner such as with tape or bandage. 
     As evident from  FIG. 3 , the elevation of the inside-foot edge  20  relative to the outside-foot edge  22  is achieved with the outside-foot edge  22  being at level above the surface  26  supporting the device  10 . To promote the retention of the foot on the upper surface  24 , a raised lip  30  is shown as being defined along the outside-foot edge  22 . Use of the device  10  shown in  FIG. 3  can be similar to that described for the embodiment of  FIGS. 1 and 2 . In particular, the device  10  can be used as a freestanding structure, in which case a user is able to place his or her heel against the upper surface  24  at the heel end  16  of the wedge portion  12 , place his or her toes against the upper surface  24  at the toe end  18  of the wedge portion  12  to cause supination and locking of the foot, and then shift his or her weight to the foot to cause weight-bearing stretching of the Achilles complex. Similar to the embodiment of  FIGS. 1 and 2 , though the wedge portion  12  is specifically configured for stretching the Achilles complex of either the right or left foot, the wedge portion  12  can also be used to pronate the opposite foot for the purpose of stretching the arch of that foot. 
       FIG. 4  shows an optional feature of the invention, in which the wedge portion  12  is equipped with a rocker feature  44  that can increase the stretching motion further by allowing the wedge portion  12  to be pitched fore and aft. The rocker feature  44  can be formed integrally with the base portion  14 , such that the lower surface of the base portion  14  defines the rocker feature  4 . Another option is to form the rocker feature  44  as a discrete accessory that can be attached to the lower (flat) surface of the base portion  14 . 
       FIGS. 5 and 6  show alternative applications for the wedge portion  12  of  FIG. 3  in which the wedge portion  12  is sized for placement in a shoe  40  ( FIG. 5 ) or as an integral or attachable portion for the sole of a shoe  40  ( FIG. 6 ). In either case, as a result of the wedge portion  12  being combined with a shoe  40 , the user can don the shoe  40  to cause supination and locking of the foot, and then walk in the shoe  40  to cause weight-bearing stretching of the Achilles complex. 
     Alternatively, the device  10  can be used in combination with a leg splint  42  ( FIG. 7 ), in which case the nonconstant elevation of the surface  24  of the wedge portion  12  can be achieved as a result of the splint  42  serving as all or part of the base portion  14  to cause twisting of the wedge portion  12  to induce supination of the foot on which the splint  42  is installed and, as a result, continuous stretching of the Achilles tendon of that foot. Still another option for the device  10  of  FIG. 3  is shown in  FIG. 8 , in which straps  31  are shown attached to the device  10  and whose ends can be grasped and pulled by a user to twist the wedge portion  12  to induce supination of the foot and cause stretching of the Achilles tendon of that foot. Finally, as with the embodiments of  FIGS. 1 through 4 , the wedge portions  12  of  FIGS. 5 through 8  can also be used to pronate the foot opposite the intended foot for the purpose of stretching the arch of that foot. 
       FIGS. 9 through 11  represent another embodiment of the invention in which the device  10  is a freestanding structure and the wedge portions  12   a  and  12   b  are coupled together by the base portion  14 . This embodiment provides the additional capability of adjusting the elevations of the surfaces  24  of the wedge portions  12   a  and  12   b  relative to the base portion  14  through an adjustment feature built into the base portion  14 . This capability enables the device  10  to allow a user to tailor the degree of stretching to meet his/her flexibility. 
     The wedge portions  12   a  and  12   b  are shown in  FIGS. 9 to 11  as pivotably attached to the base portion  14 , such as with hinges  32  either assembled to or formed integrally with the wedge portions  12   a  and  12   b  and base portion  14 . The hinges  32  are located at the outside-foot edge  22  of each wedge portion  12   a  and  12   b , while the remaining perimeter of each wedge portion  12   a  and  12   b  (defined by the heel and toe ends  16  and  18  and the inside-foot edge  20 ) is not coupled to the base portion  14 . The wedge portions  12   a  and  12   b  have the lateral taper ascribed to the prior embodiments, though more so as the upper surface  24  of each wedge portion  12   a  and  12   b  is essentially triangular-shaped. The base portion  14  is represented as constructed of a face plate  14   c  attached to a frame  14   d . The frame  14   d  provides the structural support for a pair of threaded rod and nut assemblies  34 , by which rotation of each rod causes its corresponding nut to move linearly. As evident from  FIGS. 9 to 11 , an abutment member  36  is attached to each nut, such that rotation of the rod also causes the abutment member  36  to move linearly. Each rod and nut assembly  36  is oriented transverse to the fore-aft directions of the wedge portions  12   a  and  12   b , which have tapered rails  38  that extend downward therefrom into the enclosure defined by the frame  14   d . The rails  38  and abutment members  36  are sized and arranged so that each abutment member  36  can be linearly moved by a rod and nut assembly  34  into engagement with its rail  38  to cause the corresponding wedge portion  12   a / 12   b  to pivot relative to the base portion  14  and increase the elevation of its upper surface  24  relative to the base portion  14 . It should be apparent from  FIG. 9  that the rod and nut assemblies  34  and the rails  38  they engage could be oriented parallel to the fore-aft directions of the wedge portions  12   a  and  12   b  and still be capable of elevating and lowering the wedge portions  12   a  and  12   b . Furthermore, it should be noted that other actuation mechanisms could be used in place of the rod and nut assembly  36 , including pistons, expanders, jacks, and rack and pinion mechanisms. 
     Lastly, the embodiment of  FIGS. 12 through 14  is represented as a separate freestanding body similar to that shown and described in reference to FIG.  3 , but with the further inclusion of a projection  46  disposed on the upper surface  24  of the wedge portion. From the following, it should be understood that the projection  46  and additional features discussed below in reference to  FIGS. 12 through 14  can be employed with any of the embodiments shown in  FIGS. 1 through 11 . 
     Similar to the therapeutic device  10  of  FIG. 3 , the device  10  represented in  FIGS. 12 through 14  includes wedge and base portions  12  and  14 , with the wedge portion  12  having oppositely-disposed heel and toe ends  16  and  18  in the fore-aft direction and oppositely-disposed inside-foot and outside-foot edges  20  and  22  in the lateral direction. Furthermore, the upper surface  24  of the wedge portion  12  is delineated by the heel and toe ends  16  and  18  and by the inside-foot and outside-foot edges  20  and  22 . As with the device  10  of  FIG. 3 , the upper surface  24  comprises a planar surface portion  24   a  that lies in a wedge plane  48 . However, due to the presence of the projection  46 , the device  10  of  FIGS. 12 through 14  further comprises an arcuate surface portion  24   b  defined by the projection  46 . The projection  46  and its arcuate surface portion  24   b  extend out of the wedge plane  48 , as particularly evident from  FIG. 13 . As with the upper surface  24  of the prior embodiments, the planar surface portion  24   a  lying in the wedge plane  48  has a nonuniform elevation relative to the base portion  14  as a result of the wedge portion  12  having a fore-aft taper in the fore-aft direction and a lateral taper in the lateral direction, such that the inside-foot edge  20  has a higher elevation at the toe end  18  than at the heel end  16 . In contrast, the outside-foot edge  22  can have a substantially constant elevation in the fore-aft direction. 
     As seen in  FIG. 12 , the projection  46  extends from the inside-foot edge  20  toward but not to the outside-foot edge  24  in the lateral direction, and extends between but not to the heel and toe ends  16  and  18  of the wedge portion  12 , essentially placing the projection  46  at a location corresponding to the arch of a user&#39;s foot. In a preferred embodiment, the projection  46  extends up to about 6.5 centimeters, more preferably about 4.5 to about 6.5 centimeters, from the inside-foot edge  20  toward the outside-foot edge  24  in the lateral direction, and extends about 9 to about 11 centimeters, for example about 10 centimeters, along the inside-foot edge  20  in the fore-aft direction. Furthermore, the projection  46  may be spaced a distance of about 8 to about 9.5 centimeters, more preferably about 9 centimeters, from both the heel and toe ends  16  and  18 . 
     The arcuate surface portion  24   b  defined by the projection  46  is intended to correspond to the size, shape and location of the arch of a human foot. As such, the projection  46  can be seen in  FIGS. 12 through 14  to define continuous arcuate contours in both the lateral and fore-aft directions of the wedge portion  12 , terminating at the planar surface portion  24   a  or the inside-foot edge  20 . These arcuate contours can be, for example, sinusoidal or parabolic in shape. To provide adequate support for the arch, the contours of the surface portion  24   b  preferably define an apex that is at least ten millimeters, for example, about ten to about forty millimeters, from the wedge plane  48 .  FIGS. 12 through 14  represent the apex as located at the inside-foot edge  20 , generally consistent with the shape and location of the arch of a human foot. The surface of the surface portions  24   a  and  24   b  are represented as including small raised features  50 , which can be configured to provide a slip-resistant surface texture or serve as acupuncture bumps. 
     Though represented as adapted to accommodate only one foot (for illustrative purposes,  FIGS. 12 through 14  depict a right-footed device  10 ), the device  10  could be readily configured to accommodate both feet, as shown in  FIGS. 1 ,  2  and  9 - 11  and as previously discussed in reference to  FIG. 3 , in which case the device  10  would further include a second wedge portion and projection that are preferably mirror images of the wedge portion  12  and projection  46  shown in  FIGS. 12 through 14 . The projection  46  is represented in  FIGS. 12 through 14  as integrally formed with the remainder of the device  10 , for example, part of a freestanding body formed as a one-piece molding of a hard plastic or rubber material. As a result, the projection  46  may have a fixed shape and height. Alternatively, the projection  46  could be a removable feature allowing projections  46  of different shapes and heights to be installed on the upper surface  24  of the wedge portion  12 . Furthermore, the projection  46  could be configured so that its height and shape is adjustable. For example, the projection  46  could be a hollow feature that allows its shape and height to be altered by injecting air or another suitable fluid (liquid or gas) into a cavity located beneath the surface portion  24   b , for example, between the surface portion  24   b  and the wedge plane  48 . In addition, the projection  46  could be adjusted by various other means, for example, with a jack and pinion, 
     Consistent with the prior embodiments, the fore-aft and lateral tapers of the wedge portion  12  are sufficient so that placement of a user&#39;s foot against the upper surface  24  of the wedge portion  12  causes supination and locking of the foot to enable stretching of the Achilles complex. More particularly, the user&#39;s heel is supported at the heel end  16  by the planar surface portion  24   a , and the user&#39;s toes are supported at the toe end  18  by the planar surface portion  24   a . Additionally, the arch of the user&#39;s foot is against and supported by the arcuate surface portion  24   b  between the heel and toe ends  16  and  18  of the wedge portion  12 , with the result that the projection  46  at least minimizes if not avoids stretching of the arch of the foot while a user stretches their calf muscles and Achilles tendon with the device  10 . As such, the device  10  represented in  FIGS. 12 through 14  is capable of avoiding the creation or worsening of a flatfoot condition. 
     While the invention has been described in terms of specific embodiments, it is apparent that other forms could be adopted by one skilled in the art. For example, the physical configuration of the wedges and foot plates could differ from that shown, and materials and processes other than those noted could be used. Therefore, the scope of the invention is to be limited only by the following claims.