Note: Descriptions are shown in the official language in which they were submitted.
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ACHILLES AND FOOT ARCH STRETCHING DEVICES AND
METHODS PERFORMED THEREWITH
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No.
61/164,975, filed March 31, 2009, the contents of which are incorporated
herein by
reference.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to therapy and physical fitness
equipment, and more particularly to devices capable of stretching of the calf
muscle-
Achilles tendon unit.
[0003] 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.
[0004] The normal human foot is a dynamic structure that can function as a
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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.
[0005] 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
[0006] The present invention provides therapeutic devices and methods suitable
for stretching the Achilles tendon. The devices provide for supination of the
forefoot
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to make the foot more rigid and allow better stretching of the calf muscle-
Achilles
unit.
[0007] 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 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 an increasing
elevation toward the toe end and the outside-foot edge has a substantially
constant
elevation in the fore-aft direction. The wedge portion further has a
nonconstant
lateral width in the lateral direction wherein the wedge portion has a toe
width at the
toe end thereof that is greater than a heel width at the heel end thereof. The
fore-aft
taper and the lateral taper are sufficient so that placement of a user's heel
on the
upper surface at the heel end and the user's toes on the upper surface at the
toe
end causes supination and locking of the foot and enables stretching of the
Achilles
complex.
[0008] 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
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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.
[0009] 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.
[0010] 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, stretching of the arch of the foot is minimized if not avoided,
avoiding
the creation or worsening of a flatfoot condition.
[0011] Other aspects and advantages of this invention will be better
appreciated
from the following detailed description.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0012] 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.
[0013] FIG. 3 is a perspective view of a freestanding Achilles tendon
stretching
device in accordance with a second embodiment of this invention.
[0014] 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.
[0015] 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.
[0016] 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
DETAILED DESCRIPTION OF THE INVENTION
[0017] 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
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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.
[0018] FIGS. 1 and 2 represent a freestanding Achilles tendon stretching
device
in accordance with a first embodiment of this invention. The device 10 is
shown
as having wedge portions 12 comprising a left wedge portion 12a and a right
wedge
portion 12b, 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 14a and 14b 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.
[0019] The upper surface 24 of each wedge portion 12 is shown to have a
nonuniform elevation relative to the base portion 16 as a result of the size
and
shape of the risers 14a and 14b. In particular, the riser 14a adjacent the
heel ends
16 of the wedge portions 12 is smaller than the riser 14b 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
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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.
[0020] 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'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.
[0021] 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 12a and 12b could differ to achieve a different degree of stretching
for the
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left and right feet.
[0022] 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.
[0023] Various materials can be used in the construction of the device 10
shown
in FIGS. 1 and 2, including but not limited to plastic, 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
12a
and 12b 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
can be equipped with straps 28 or other means for individually securing the
user's foot or feet to the wedge portions 12.
[0024] The embodiments of FIGS. 3 through 11 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.
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[0025] 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 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.
[0026] 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
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arch of that foot.
[0027] 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.
[0028] 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.
[0029] 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
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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.
[0030] FIGS. 9 through 11 represent another embodiment of the invention in
which the device 10 is a freestanding structure and the wedge portions 12a and
12b
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 12a and 12b 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.
[0031] The wedge portions 12a and 12b 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 12a and 12b and base portion 14. The
hinges 32 are located at the outside-foot edge 22 of each wedge portion 12a
and
12b, while the remaining perimeter of each wedge portion 12a and 12b (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 12a and 12b have the lateral taper
ascribed
to the prior embodiments, though more so as the upper surface 24 of each wedge
portion 12a and 12b is essentially triangular-shaped. The base portion 14 is
represented as constructed of a face plate 14c attached to a frame 14d. The
frame
14d provides the structural support fora 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 12a and 12b, which have tapered rails 38 that extend downward
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therefrom into the enclosure defined by the frame 14d. 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 36 into engagement with its rail 38
to
cause the corresponding wedge portion 12a/1 2b to pivot relative to the base
portion
14 and increase the elevation of its upper surface 24 relative to the base
portion 14.
Is should be apparent from the foregoing 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.
[0032] 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.
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