Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DEVICE FOR HIGH-HEELED SHOES AND
METHOD OF CONSTRUCTING A HIGH-HEELED SHOE
The present invention relates to a shoe that is easily constructed and
provides greater
comfort to the wearer without affecting the fit or style of the shoe. The
invention has
particular utility in connection with high-heeled shoes and will be described
in connection
with such utility, although the invention also has utility in connection with
low heel
footwear products as well.
Conventional high-heeled shoes have a reputation for being extremely
uncomfortable. There is survey information indicating that as many as 20% of
the users of
such shoes experience foot pain related to the shoes immediately, and the
majority of users
experience such pain after as little as four hours of use.
In order to understand the prior art and the present invention, it is
necessary to
understand the anatomy of the foot and the basics of shoe construction. To
that end, FIG. 1
is a diagrammatic view of the bones of the foot and the portions of a shoe
that underlie the
sole of the foot. By reference to FIG. 1, the following briefly describes the
anatomy of the
foot and the basics of shoe construction.
FIG. 1 is a diagrammatic medial side view of the bones of the human foot 10.
For
purposes of this application, references to rearward mean in the direction of
the rear of the
foot or heel 20; references to forward or toeward mean in the direction of the
front of the
foot 30 where the toes or phalanges 31 are located; references to medial mean
the side of the
foot where the arch 40 is located; references to lateral mean the outside of
the foot; and
references to upper or top and lower, bottom or under assume the foot or shoe
is oriented in
an upright position.
The heel 20 (also known as the tarsus) includes the talus 21 and the calcaneus
22
bones. The rear lower surface of the calcaneus 22 has a slight protuberance 23
known as the
calcaneal tuberosity.
Referring to FIG. 1A, the calcaneus is an irregularly shaped quadrangular bone
also
called the heel bone or os calcis. As can be seen particularly in FIG. 1A, the
medial side of
the calcaneal tuberosity, i.e. the lower part of the posterior surface of the
calcaneus is not
precisely on the same ground or plane as the lateral tuberosity. This slight
difference in
calcaneal anatomy leads to ankle instability particularly for wearers of high
heel shoes.
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The bones of the foot also include the navicular 41, the cuneiform 42, the
metatarsals
45 and the phalanges, or toes, with the big toe 31 visible in FIG. 1. The
metatarsal heads 46
are located at the forward end of the metatarsal shafts 47. The metatarsals
are numbered 1 to
5, with 1 designating the big toe.
Also depicted in FIG. 1 is a partially exploded view of the portions of a
conventional
high-heeled shoe 50 that underlie the sole of the foot. Shoe 50 has a heel 51
which is
generally attached to the lower surface of sole 52 of shoe 50, with the sole
52 in turn
supporting the insole board 53 on which the sock liner 54 is placed. In a
conventional shoe,
the insole board is typically of relatively rigid construction from the region
underlying the
wearer's heel to the heads of the metatarsals. Sock liners are commonly very
flexible and
generally are very thin, typically no more than half a millimeter thick. The
sock liner is the
surface upon which the sole of the foot normally rests.
According to conventional shoe construction methods, the last is the form
around
which the shoe is constructed. During manufacture, the lower surface of the
last sits on the
upper surface of insole board, and the shoe upper is then shaped around the
last and attached
to the insole board. Optimally, the lower surface of the last and the upper
surface of the
insole board fit together smoothly in order to properly manufacture shoes. If
there is any
convexity on the lower surface of the last or the upper surface of the insole
board
respectively, a corresponding concavity must be present in the insole board or
last
respectively. To be assured of a quality shoe construction, any such convexity
and
corresponding concavity must be carefully aligned during shoe manufacture,
thereby
introducing added complexity and/or quality control issues to shoe
manufacture.
As will be appreciated, a conventional high-heeled shoe such as shown in FIG.
1
places the rearward part of the wearer's foot essentially on an inclined
plane. As a result, the
foot is urged forward by gravity into the toe box in standing or walking. This
results in
pressure on the ball or forefoot regions and toe jamming which often gives
rise to a burning
sensation in these areas of the foot, as well as fatigue and discomfort in the
foot and other
areas of the body.
Numerous suggestions have been made for improving the comfort of high-heeled
shoes, including suggestions in my prior patents and publications. For
example, in a
February 1990 article in Current Podiatric Medicine, pp. 29-32, I described a
high-heeled
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shoe design in which the portion of the shoe under the heel does not form a
continuous ramp
down the arch to the ball of the foot, but rather the portion underlying the
heel is relatively
parallel to the ground. The design used a rigid plastic molded midsole which
was cupped to
receive the heel and angled to bring the heel into a plane more parallel with
the floor. In
addition, a metatarsal pad was incorporated into the molded midsole.
In U.S. Pat. No. 5,373,650, I described a rigid or semirigid orthotic under
the heel
and extending forward, with arch support, to a point behind the metatarsal
heads of the foot.
The heel in this device is supported parallel to the ground or tilted slightly
backwards.
In U.S. Pat. No. 5,782,015, I described a high-heeled shoe design in which the
heel is
positioned more parallel or slightly downwardly inclined angle relative to the
shank plane
and which has an arch support that supports the head of the navicular in
approximately the
same plane as the wearer's heel bones. My PCT Publication W098/14083,
published Apr. 9,
1998, describes a rigid molded device comprising a heel cup and an
anatomically shaped
arch appliance.
Numerous examples of designs by others intended to improve comfort of high-
heeled shoes exist in the prior art. U.S. Pat. Nos. 1,864,999, 1,907,997,
4,317,293,
4,631,841, 4,686,993, 4,932,141 and 6,412,198 each describes shoe inserts or
orthotics
intended to improve comfort of a high-heeled shoe. Several involve arch
supports. Some are
rigid; others suggest cushioning as a means to improve comfort. The prior art
inserts and
orthotics typically are relatively bulky and can affect a shoe's fit if added
by the wearer after
manufacture. Other prior art proposals to improve wearer comfort require that
each last used
to manufacture the shoe be modified to change the shape of the shoe itself.
These prior art constructions improve comfort by supporting or cushioning
parts of
the foot and/or altering the foot angles to reduce sliding forward and/or to
alter the
percentage of the wearer's weight borne by different parts of the foot. Their
teachings
suggest, among other things, placing the heel on a more level plane to shift
the weight
backward onto the heel, supporting the arch, angling the toes upward and/or
cushioning the
surfaces on which the largest percentage of weight is borne.
The foregoing discussion of the prior art derives primarily from my earlier
U.S.
Patent 7,322,132 in which I provide a thin flexible shoe insert which readily
can be adapted
to any style shoe and which can be incorporated into a shoe without requiring
modifications
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to a shoe last or adding manufacturing complexity. The insert has two slightly
raised areas
under the heel and the metatarsals. Although the insert has two only slightly
raised areas, it
significantly increases wearer comfort even in very high heels. The insert
does not require
that the heel be repositioned to a plane parallel with the floor as is the
case in some of the
prior art. Other than in the two slightly raised areas, the insert can be
extremely thin, thereby
minimizing any effect on fit of the shoe and eliminating any adverse effect on
the style or
appearance of the shoe. Alternatively, the thin flexible insert can be placed
in the shoe by
the wearer. See also my U.S. Patent Nos. 7,595,346, 7,814,688 and 7,962,986.
While high heel shoes in accordance with my aforesaid US'132, '346, '688 and
'986
patents enjoy considerable commercial success and are available from a number
of
manufacturers in numerous countries, I have found that changing the shape of
the heel
region to better accommodate the plantar surface of the calcaneal tuberosity,
comfort and
ankle stability is unexpectedly and significantly improved for both high-
heeled shoes, as
well as low heel shoes and flats. More particular, the present invention
provides a device for
insertion into heeled shoes and the corresponding method of constructing shoes
using the
device. The device comprises a rear region positioned to underlie the
calcaneal tuberosity
the wearer. The rear region is shaped to accommodate the plantar surface of
the calcaneal
tuberosities and includes first and second essentially ellipsoid shaped
depressions to
accommodate the calcaneal tuberosity of the wearer. The first depression, on
the
medial/inside of the device, i.e., under the medial tuberosity, is the larger
of the two
depressions, and is slightly deeper than the second depression on the
lateral/outside of the
device. Typically the depression on the medial/inside is 2-5 times larger than
the depression
on the lateral/outside preferably 2- 4 times larger, more preferably 21/2 - 3
times larger, most
preferably about 2.7 times larger in plan, and the base level of the
depression under the
lateral tuberosity is slightly higher, e.g., about 0.1-3 mm higher, more
preferably 0.1-2 mm
higher, most preferably about 0.3 mm higher over the base level of the
depression under the
medial tuberosity to accommodate the calcaneal tuberosity of the wearer. The
toeward
portions of the first and second depressions gradually rise to crescent shaped
apices lying
under the area forward of the tuberosity of the calcaneus. The device also
includes a
forward region positioned to underlie at least a portion of the shafts of the
metatarsals, the
upper surface of said forward region having a portion which gradually rises to
an apex
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positioned to underlie the shafts of the second and third metatarsals. In the
preferred
embodiment, the device has a bridging or middle region which connects the
forward and
rear regions, the device is flexible and the upper surface of the device is
smoothly contoured
between all regions. A feature and advantage of the device of the present
invention is that
the device may universally be applied to conventional heeled shoes without the
need to
otherwise modify the shoes or the shoe last. A shoe may be constructed with
the device
according to the present invention by incorporating the device into the shoe
during the
manufacturing process or the device may be applied post-manufacture by the
wearer.
FIG. 1 is a diagrammatic cross-sectional view of the foot bones and a
partially
exploded view of the portions of a conventional high-heeled shoe that underlie
the sole of
the foot.
FIG. lA is a rear view of the calcaneus.
FIG. 2A and 2B are top plan views of an embodiment of the device of the
present
invention showing right (Fig. 2A) and left (Fig. 2B) shoe devices.
FIG. 3 is a side cross-sectional view of the device of the present invention
shown in
FIG. 2B, taken along plane "III-III."
FIG. 4 is a contour drawing of the device of Fig. 2A.
FIG. 5 is a diagrammatic cross-sectional view of the foot bones and a
partially
exploded view of the portions of a conventional high-heeled shoe that underlie
the sole of
the foot into which the device of the present invention shown in FIG. 2 has
been inserted.
FIGs. 6A-6D are views, similar to Figs 2A and 2B, of an alternative embodiment
of
the invention.
As used herein "heeled shoes" shall include high heeled shoes, low heeled
shoes and
flats. The present invention provides a device which improves comfort and is
easily installed
in heeled shoes. For purposes of this invention, it is to be understood that
heeled shoes
include all footwear having a heel which is about one inch or higher. The
benefits of the
invention are achieved when a device is positioned in a shoe to underlie the
metatarsal shafts
and calcaneus of the wearer. Typically, the device is positioned on the insole
board or sock
liner of a heeled shoe. Preferably, the device is sufficiently flexible so
that it readily
conforms to the upper surface of the insole board or sock liner on which it is
positioned. The
device may be formed of any materials known to those of ordinary skill in the
art that can be
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molded or shaped and that will produce a device flexible under normal
conditions of use of a
shoe, while retaining sufficient dimensional stability to retain the benefit
of the invention.
In the preferred embodiment, the device is shaped to underlie at least (i) the
portion
of the heel extending from the edge of the tuberosity of the calcaneus to the
portion of the
heel that is immediately forward of the tuberosity of the calcaneus, and (ii)
the area under
the second and third metatarsal shafts. The device may extend beyond these
areas and may
be shaped to conform to the shape of the sock liner or insole board.
Optimally, the device is
narrower than the sock liner when it is to be positioned under the sock liner.
This narrower
size allows the edge of the sock liner to be adhered to the insole board along
the edges of the
device of the invention. Depending on the style of the shoes this narrower
configuration may
be particularly desirable.
The device has two distinct areas: a first distinct heel area that underlies
the
calcaneal tuberosities of the wearer, and which has two depressed areas shaped
generally to
accommodate respectively the lateral and medial tuberosities of the wearer's
calcaneal
anatomy. The depressed areas rise from their respective forward edges of the
tuberosity of
the calcaneus to a crescent-shaped apices underlying the calcaneus in the area
forward of the
tuberosity of the calcaneus of the wearer's foot. The device also includes a
second distinct
raised area located within a shoe to underlie the metatarsal shafts of the
wearer's foot, with
its apex under or between the second and third metatarsal shafts. The first
and second raised
areas are joined by a bridging or middle region. For clarity, it is to be
understood that
references to narrow and wide mean the side-to-side dimensions of the shoe or
device while
references to raised, lowered, thinness, depth or height mean the vertical
dimensions of the
device.
FIGS. 2-5 illustrate an exemplary embodiment of a device 100 consistent with
the
invention. The device 100 is formed from a flexible material, e.g., molded
flexible plastic or
rubber, such as polyurethane, thermoplastic elastomer (TPE), thermoplastic
rubber (TPR),
polyvinyl chloride (PVC) or ethylene vinyl acetate (EVA). The raised areas of
the device
have a Shore A hardness between about 15 and 70, and preferably have a Shore A
hardness
of about 20 to 50, and most preferably about 35. The entire device preferably
but not
necessarily is of the same hardness. The device 100 has a forward region 110
and a rear
region 120. The device includes three raised areas 130, 135 and 140. Raised
areas 130 and
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135, located in the rear region, are generally crescent-shaped and positioned
in a shoe to
underlie the area immediately in front of the tuberosity 23 of the heel bone
or calcaneus 22
of the wearer's foot. The crescent-shaped raised areas 130 and 135 rise from
depressions as
will be described below found in the heel portion of the device so that the
crescents are
oriented as shown in FIGS. 2-5.
Referring in particular to FIGs. 2A-2B, FIG 3 and FIG 4, the device includes a
lop-
sided generally cardioid shaped depression including a first depressed area
136 located
directly under the lateral tuberosity of the wearer's calcaneal anatomy, and a
second
depressed area 138 located under the medial tuberosity of the wearer's
calcaneal anatomy.
The base level of depressed area 136 under the lateral tuberosity is slightly
higher, typically
about 0.1-3 mm higher, preferably about 0.1-2 mm higher, most preferably about
0.3 mm
higher, over the base level of depressed area 138 under the medial tuberosity
to
accommodate the calcaneal tuberosity of the wearer. Depressed area 138 under
the medial
tuberosity is 2-5 times larger in plan, preferably 2-4 times larger, more
preferably 21/2 -3
.. times larger, most preferably about 2.7 times larger in plan, than the area
136 under the
lateral tuberosity. Both depressed areas 136 and 138 are generally ellipsoid
in shape. More
particularly, the first and second depressed areas 136, 138 can be described
as first and
second depressed areas defined by the Boolean subtraction of the larger of two
3D ellipses
from the smaller, the larger ellipse being 40 to 120 percent larger in volume
than the
smaller ellipse, preferably 60 to100 percent larger in volume, more preferably
about 80
percent larger in volume than the smaller ellipse with larger skewed to the
medial side and
the smaller skewed to the lateral, with the intersecting volume being 10 to 30
percent of the
larger, more preferably about 20 of the larger, with the longer axis of both
aligned with the
heel/toe direction of the device, and with the medial/lateral axis of the
smaller skewed
slightly to the rear of the larger, and both rotated such that the toe-ward
end is raised 1 to 10
degrees, preferably 3 to 8 degrees, more preferably about 5 degrees relative
to the heel-ward
end, such depressions being configured to accommodate respectively the lateral
and medial
tuberosities of the wearer's calcaneus.
A third raised area 140 is located in the forward region of the device which
is canted
to the medial side, and is positioned to underlie the metatarsal shafts 47 of
the wearer's foot.
Optimally, the apex of the third raised area 140 is located under or between
the second and
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third metatarsal shafts. The third raised area 140 comprises a generally
rounded or ellipsoid
shape that rises to an apex in the toeward direction of the metatarsal heads.
The forward
raised area 140 preferably has a thinner aspect located towards the heel end
and a wider
aspect located towards the toeward end. Since the device includes a lop-sided
section under
the heel region, and the toeward region is canted to the medial side, the
device is left/right
shoe specific, the left and right pieces being minor images of one another.
The apices of raised areas 130, 135 and 140 are 2 to 8 mm higher relative to
the
bottom surface of the device and, preferably 2 to 6 mm higher, more preferably
2.5 to 4.5
mm, most preferably about 3.8 mm higher relative to the bottom surface of the
device
measured immediately forward of the forward raised area under the metatarsal
shafts and
immediately rearward of the raised areas under the calcaneus. In a
particularly preferred
embodiment each apex 130, 135 and 140 is approximately 3.3 mm high for a US
size 1
women's shoe, approximately 3.9 mm higher for a US size 6 woman's shoe, and
approximately 5.2 mm for a US size 16 women's shoe high relative to the bottom
surface of
the device (or their equivalents in other, e.g. English, European and Japanese
shoe size
scales) having a heel height of 1 to 5 inches. A bridge area 160 separates
depressed areas
136 and 138, and is also depressed relative to the upper surface of the device
surrounding
the depressed areas 136 and 138. In the preferred embodiment the apices 130,
135 and 140
are of similar or the same height. Preferably, each apex 130, 135 and 140 is
higher for
higher heeled shoes and lower for lower heeled shoes. Also, each apex 130, 135
and 140
preferably is lower for smaller sized shoes and higher for larger sized shoes.
The size of
raised areas 130, 135 and 140 also changes somewhat with shoe size with the
size of the
area increasing with increasing length and/or width. Typically, the size of
the raised areas
both in terms of height and area is scaled to the shoe size with normal rules
of scaling
applying as the length and width of the shoes increases with increasing size.
However, it has
been found that a small range of sizes can use an identical device without
significant loss of
the improved comfort associated with the device. The critical factor on the
comfort achieved
with the device of the invention appears to be the location of the two raised
regions--under
the calcaneus but forward of the tuberosity of the calcaneus, and under the
middle
metatarsals but rearward of the heads of the metatarsals, and the size and
location of the
depressed areas under the calcaneus tuberosity.
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Heel size from individual to individual typically varies far less than other
aspects of
foot dimensions. Accordingly, the depressed areas 136 and 138 under the
calcaneus
tuberosity may be made essentially the same for all foot sizes provided the
area under the
medial tuberosity 138 is far larger than under the lateral tuberosity 136, and
the base level of
the depressed area 136 under the lateral tuberosity is somewhat higher over
the base level of
the depressed area 137 under the medial tuberosity. The proximal and the
distal ends of the
device, i.e., underlying the back of the heel and forward of raised area 140
are thin relative
to the raised areas. Preferably these proximal and distal ends have a depth
that results in
their being flush with the upper surface of the shoe upper where it wraps
around the upper
surface of the insole board. Preferably the ends are also shaped to conform
somewhat to the
area extending between the edges of the upper that lie on the surface of the
insole board. The
thickness of these ends of the device typically will be from 0.2 to 1 mm
thick.
The bridging or middle section or area of the device between the first raised
areas
130, 135 and the second raised area 140 is also preferably thin relative to
the raised areas.
The thickness of this area is in part dictated by issues of structural
integrity during the
manufacturing process for the shoe. With stronger materials this area can, and
ideally should
be, no more than a millimeter thick. In general, this bridging or middle
section or area must
be thinner than the raised areas 130, 135 and 140, and preferably is no more
than about 4
millimeters thick, more preferably about 2 mm thick for a US size 6 women's
shoe and about
2 1/2 mm for a US size 10 women's shoe (or their equivalents in other size
scales). This
thinner bridging or middle region allows the device to more easily conform to
the shape of
the insole. The minimum width of this bridging or middle region is also
dictated by
manufacturing considerations with the optimal minimum width being that which
will
maintain the geometry of the forward and rear regions relative to each other.
The maximum
width is that which will not interfere with the appearance of the shoe.
Preferably this
bridging or middle region is narrower than the sock liner 54 and, like the
ends of the device,
the bridging or middle region sits flush with the upper surface of the upper
that wraps
around the insole board and generally confoinis to the shape of the area
created by the edges
of the upper on the insole board.
It should be noted that, contrary to the teachings of the prior art, rather
than
providing a raised area for supporting the arch of the wearer's foot in the
device of the
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present invention, at least a portion of the bridging or middle region
underlying the arch is
thinner than the apices of the first and second raised areas 130, 140. That is
to say, where a
traditional arch support normally would be located in the shoe at least a
portion of the area
underlying the arch of the foot is hollowed or lower than adjacent areas
leaving the arch
unsupported in part.
Preferably, the upper surface of the device is smoothly contoured, with no
sharp
transitions or edges that could contribute to discomfort. Specifically, the
transition between
the apices of the raised areas and the surrounding areas of the device are
filleted and smooth.
As described above, the invention contemplates a single flexible device into
which
both raised areas are incorporated. As shown in FIGs. 6A and 6B, the invention
also
contemplates two separate flexible devices, a heel area element 300 and a
metatarsal area
element 302, which together achieve the advantages of the invention. More
specifically,
FIGs. 6A and 6B shows an alternative embodiment of the device in which the
metatarsal
element 302 has a raised area 304 similar to raised area 140 of the FIG 2A/2B
embodiment,
and the heel area element has depressed areas 306/308 and raised areas 310,
312, similar to
depressed 138/136 and 130/135 of the FIG 2A/2B embodiment. In the FIG 6A/6B
embodiment, the heel piece, and the metatarsal piece are individually
positioned in a shoe.
In that case, the region between the two pieces of the device is integral with
the insole board
or the sock liner and need not be flexible. A further manufacturing
alternative is to
incorporate one or both of the heel portion and metatarsal piece into the
insole board. Yet a
further alternative is to incorporate one or both of the heel portion and the
metatarsal piece
into a sock liner. However, for ease of manufacture, a single device having
the separate
raised areas joined by a bridging or middle section is preferred. In all
cases, the portions of
the device that are mounted on the insole board of a shoe must be flexible
enough to readily
conform to the upper surface of the insole board on which they are mounted.
The invention
also contemplates a single flexible device which embodies one or the other of
the above
raised areas and which is used in conjunction with a shoe or shoe part which
incorporates
the other raised area. The invention also contemplates using only the heel
area element 300
as a heel cup. This latter embodiment has particular utility in sport shoes,
particularly where
the wearer is subjected to a lot of lateral movement, such as tennis and
basketball. Finally,
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the invention contemplates shoes into which any of the foregoing described
embodiments of
the device has been incorporated.
The device 100 preferably is positioned in shoe 50 during the manufacturing
process.
Accordingly, this invention also provides a method of constructing a heeled
shoe
comprising: (a) assembling an upper, insole board and sole; (b) mounting above
the insole
board a flexible device comprising (i) a rear region positioned with its
depressed areas to
underlie the calcaneus tuberosity of the wearer; (ii) a forward region
positioned to underlie
at least a portion of the shafts of the metatarsals, the upper surface of said
forward region
having a portion which gradually rises to an apex positioned to underlie the
shafts of the
second and third metatarsals from a position behind the heads of metatarsals;
(iii) a bridging
or middle region which connects said forward and rear regions; and (iv) the
upper surface of
said device transitioning smoothly between all regions; and (c) affixing a
sock liner to the
insole board and to the device. The order in which these steps are done is the
choice of the
manufacturer. In a preferred embodiment of the invention, the device 100 is
positioned on
the insole board 53 of the shoe 50, and then a sock liner 54 is adhered to the
top of the insole
board and the device 100. It is also contemplated that the device 100 may be
installed post-
manufacture or post-sale in certain embodiments, e.g., by being placed on the
insole board
53 or sock liner 54 post-manufacture. The device 100 may be attached to the
insole board 53
and the sock liner 54 through means such as glue, pressure-sensitive adhesive
(PSA), hook
and loop fasteners, or mechanical fasteners such as nails or staples. In
general, any means
that will cause the raised areas of the device to remain in position may be
used to position
the device in the shoe. Device 100 also need not be separate from the sock
liner but may be
integral with the sock liner.
In order to facilitate proper positioning of the device, the device may be
provided
with markings or structures that orient the device. These markings may be
arrows or the
device itself may be configured with points which serve to orient the device.
The device of the present invention provides unexpected advantages over the
prior
art. For example, although the device is only a few millimeters thick, the
device causes the
weight borne by the foot to be significantly shifted towards the heel and off
the ball of the
foot. As a result, the device reduces toe pain and general lower back pain
associated with the
wearing of heeled shoes. Thus, foot pain, endemic with the use of heeled shoes
including
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specifically high-heeled shoes, is reduced or eliminated using the instant
device. The device
also improves ankle stability.
In addition, this device does not require any change in the lasts used to
manufacture
conventional shoes; rather, the device can simply be placed into the
conventionally
constructed shoe either by the manufacturer or by the wearer. Nor does this
device
significantly affect the fit of the shoe as it does not intrude substantially
into the shoe and
thereby diminish the space available for the foot.
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