Note: Descriptions are shown in the official language in which they were submitted.
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Sole for pronation control
The present invention relates to the field of footwear, and in
particular to the field of footwear having a sole designed to provide guidance
and/or support to the wearer's foot so as to improve the gait of the wearer.
Typically, such a sole comprises in heel-to-toe sequence along the
sole: a heel portion, a midfoot portion, a ball portion and a forefoot
portion, with
the heel, midfoot and ball portions running along the lateral side of an arch
region located below the arch of the wearer's foot.
Soles of this type increase user comfort by providing cushioning
elements for the foot in some or all of the heel, midfoot, ball and forefoot
portions of the sole, primarily for dampening ground impact during running or
walking, and/or by providing support elements spread throughout the bottom
surface of the sole primarily for stabilizing the foot and preventing or at
least
minimizing any tilt of the foot in a direction transverse to the running or
walking
direction (longitudinal direction).
Wearing shoes equipped with soles of this type over extended
periods of time contributes to an attitude of indifference and passiveness in
persons using these shoes. In the long run, many of these persons will forget
how to walk naturally or "correctly". It has been shown that prolonged
unnatural
or "incorrect" walking may have deleterious effects on the entire body, such
as
knee, hip and back problems. On the other hand, there are indications that
"rediscovering" how to walk naturally can alleviate or even eliminate many
problems in a person's body.
The following sequence has been found for practically all humans to
be a natural or "correct" gait (except for sprinting):
- the first foot initially contacts the ground with its heel, or with its
heel and midfoot simultaneously;
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- the first foot then begins to roll on the ground with slight foot
deformation (and ideally without slipping), the sole of the first foot
contacting
the ground in sequence by its heel or midfoot, its ball and forefoot portions;
- towards the end of this first foot rolling action, the second foot
contacts the ground with its heel, or with its heel and midfoot
simultaneously.
The first foot is then lifted off the ground;
- the second foot then begins to roll on the ground with slight foot
deformation (and ideally without slipping), the sole of the second foot
contacting the ground in sequence by its heel or midfoot, its ball and
forefoot
-10 portions;
- at the end of this second foot rolling action, the second foot is lifted
off the ground, and at the same time, the first foot again initially contacts
the
ground with its heel or with its heel and midfoot simultaneously and the
sequence continues.
In the above sequence of alternate foot contact with the ground, a
more or less broadened/blurred ground contact line is defined on the sole of
each foot. In a person having healthy bones, tendons, muscles and nerves and
exhibiting natural gait behavior, this optimal ground contact line typically
is a
substantially/approximately S-shaped line on the sole of each foot starting at
the heel portion, passing along the midfoot and ball portions and ending at
the
forefoot portion, typically on the medial side of the forefoot portion in the
region
of the first and second metatarsals and the first and second toes.
The term "pronation" is used to describe the lateral inwards rotation
of the foot which normally occurs during its contact with the ground. A
certain
amount of pronation is considered natural and desirable for a healthy gait. If
the foot does not rotate inwards enough, the wearer is said to suffer from
supination. If the foot rotates too much, on the other hand, overpronation is
said to have occurred.
3
Reference is made in the following description to the "medial" and "lateral"
sides of the foot. The term "medial" is intended to refer to the inner side of
the foot (the
side of the foot facing the other foot), while the term "lateral" is intended
to refer to the
outer side of the foot (the side of the foot facing away from the other foot).
It is known from US patent US4759136 to correct overpronation and
underpronation/supination by means of peripheral sole regions having a higher
durometer value (hardness) than the central sole region. This combination
obliges the
foot to remain between pronation/supination limits during walking or running.
The
wearer is thereby obliged to follow a particular pronation pattern which is
predetermined primarily by the shoe geometry.
It is also known from US patent U85282326 to correct for overpronation and
underpronation/supination by means of appropriately placed footwear inserts.
These
have the advantage of increasing wearer comfort, by compensating for over- and
underpronation, but they are ineffective at encouraging the wearer to develop
a
healthier gait.
It is therefore an object of the present invention to overcome the above and
other disadvantages in footwear soles known in the prior art. In particular,
it is an
objective of the prior art to provide a footwear sole which provides
sufficient sensory
information to the wearer's foot to encourage the foot to auto-correct
overpronation or
supination.
To this end, the invention aims to provide a sole for an article of footwear,
the
sole comprising:
a midsole body element for providing resilient support for the wearer's foot,
the midsole body element comprising at least an elastically compressible first
material
having a first durometer and extending over a majority of the area of the
sole,
a longitudinal pronation guiding element, comprising a second material
having a second durometer, greater than the first durometer, configured to
provide the
wearer's foot with longitudinal pronation guidance during walking or running,
the
longitudinal pronation guiding element being substantially narrower than the
width of
the sole and extending along a predetermined, substantially S-shaped
longitudinal line
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of optimum gait pressure from a heel region of the longitudinal pronation
guiding
element to a toe region of the longitudinal pronation guiding element, such
that the
wearer feels the substantially S-shaped line as a pressure line at the bottom
surface of
his or her foot while walking or running,
the longitudinal pronation guiding element being located in a foot-facing
surface of the midsole body element
wherein the longitudinal guiding element comprises a rolling gait
enhancement element for enhancing a rolling gait of the wearer, such that the
longitudinal guiding element provides both the said pronation guidance and the
said
rolling gait enhancement
According to a variant of the invention, the sole may comprise a medial
pronation control element for resisting overpronation of the wearer's foot
during an
initial contact phase of the foot with the ground when walking or running,
wherein the
medial pronation control element is located on the medial side of the midsole
body
element and substantially in the rear half of the midsole body element, and
wherein the
medial pronation control element comprises a resilient third material having a
third
durometer, greater than the first durometer.
According to a further variant of the invention, the sole may comprise a
lateral pronation control element for resisting supination of the wearer's
foot during a
mid-gait contact phase of the foot with the ground when walking or running,
wherein
the lateral pronation control element is located in a region of the lateral
side of the
midsole body element and at least in a portion of the said lateral side which
is at a mid-
point along the length of the sole, and wherein the lateral pronation control
element
comprises a resilient fourth material having a fourth durometer, greater than
the first
durometer.
According to another variant of the invention, the second durometer may be
at least 10 Shore greater than the first durometer.
According to another variant of the invention, the second durometer may be
at least 20 Shore greater than the first durometer.
Date Recue/Date Received 2020-06-29
5
According to another variant of the invention, the first durometer may be in
the range 30 to 50 Shore.
According to another variant of the invention, the longitudinal pronation
guiding element comprises, along its length in heel-to-toe order, a heel
region, a mid-
foot region, a ball region and a toe region, and wherein the rolling gait
enhancement
element is configured to provide a greater total durometer of the sole at the
mid-foot
region of the longitudinal pronation guiding element than at the heel or toe
regions.
According to another variant of the invention, the gait enhancement element
comprises a thickening of the longitudinal pronation guiding element in the
mid-foot
region.
According to another variant of the invention, the thickness of the
longitudinal
pronation guiding element is greater, and the thickness of the midsole body
element
smaller, in the mid-foot region than in the adjacent heel and ball regions,
such that the
combined durometer of the longitudinal pronation guiding element and the
midsole
body element in the mid-foot region is substantially greater than the combined
durometer of the longitudinal pronation guiding element and the midsole body
element
in the adjacent heel and ball regions.
According to another variant of the invention, the thickness of the mid-foot
region of the longitudinal pronation guiding element is substantially equal to
the
thickness of the midsole body element in the mid-foot region.
According to another variant of the invention, the sole comprises an outsole
for providing a ground-contacting outer surface for the sole, the outsole
comprising at
least one fifth material having a fifth durometer greater than the first
durometer, and
extending over a majority of the area of the sole, and the thickness of the
mid-foot
region of the longitudinal pronation guiding element is substantially equal to
the
combined thickness of the midsole body element and the outsole in the mid-foot
region,
and wherein the outsole comprises an
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opening such that the secondmaterial of the the mid-foot region of the
longitudinal pronation guiding element extends into the opening in the
outsole.
According to another variant of the invention, at least one of the
medial pronation control element, the lateral pronation control element, the
longitudinal pronation guiding element and the gait enhancement element is
formed as a contiguous region of the mid sole body element.
According to another variant of the invention, the longitudinal
pronation guiding element has substantially parallel top and bottom surfaces
in
one or more of the heel, the mid-foot, the ball and the toe regions.
According to another variant of the invention, the top and bottom
surfaces of the longitudinal pronation guiding element are angled relative to
each other across the longitudinal pronation guiding element such that the
longitudinal pronation guiding element has a substantially wedge-shaped
transverse cross-section.
According to another variant of the invention, one or both of the top
and bottom surfaces of the longitudinal pronation guiding element has a curved
shape in transverse cross-section.
Due to the insole at or close to the foot-contact surface of the sole, a
walker or runner wearing a shoe provided with the sole according to the
invention experiences increased or concentrated pressure between the insole
and the bottom surface of his foot. As a result, the walker or runner feels
the
substantially S-shaped line as a pressure line at the bottom surface of his
foot.
Due to extra hardness of the sole in a cross-sectional direction
transverse to the locally longitudinal direction or tangential direction along
the
substantially S-shaped line of optimal ground contact, a wearer will feel more
pressure or support from points located on that line than from points located
outside that line, ie off that line and thus will experience "instant
feedback" and
"feel" during walking or running whenever he or she deviates from the line of
optimal ground contact.
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The expressions "pressure" or "support" or "pressure force" or
"support force" are used as synonyms in the present text and are all defined
as
average measured force per unit area where the force is measured using a
vertically sensitive force meter having a horizontally planar force receiving
surface having a defined area. The "pressure" or "support" or "pressure force"
or "support force" value is calculated as "the measured vertical force acting
on
the force receiving surface divided by the area of the force receiving
surface".
Typical support force values may relate to the static support forces measured
during standing or the instantaneous dynamic support forces measured during
walking, more specifically the locally acting reaction forces (ground forces)
in
the ground-contacting regions of the sole during the rolling action of a foot
on
the ground.
As long as the direction of the dynamic force vector resulting from
the static weight and the dynamic force during the rolling action of each foot
passes through the line of optimal ground contact, there is no or at least
hardly
any tilting action on the foot which would cause the foot to pronate (tilt
medially
towards the inside) or supinate (tilt laterally towards the outside), ie in a
direction transverse to the walking or running direction, with respect to the
shinbone.
The person wearing a sole according to the invention is encouraged
by the proprioception sensation from the longitudinal pronation guiding
element
2 to reposition his or her weight and foot orientation whenever he or she
deviates from the line of optimal ground contact, resulting in the desired
correction of posture and gait . Thus the wearer perform a subconscious auto-
correction of the pronation/supination of the foot, corresponding to the line
of
optimal ground contact defined by the relatively hard longitudinal pronation
guiding element. The foot's heel-to-toe contact line with the ground tends to
follow the path of greatest pressure, and the wearer's gait is therefore
corrected by providing a path of harder material, having the shape of the
desired contact line.
The subconscious auto-correction involves many parts of the body,
including ankle joints, knee joints, hip joints, vertebral column and
associated
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tendons, muscles and nerves, and has a beneficial influence on the entire
body.
The longitudinal pronation guiding element extending along the
substantially S-shaped line and contacting the foot contributes to the
feedback
to the walker or runner as described above. Thus, the walker's or runner's
senses detect any deviation of his foot from its ideal orientation during
walking
or running. This feedback sensing process is referred to as proprioception.
The invention will now be described with reference to the
accompanying drawings, in which:
Figure 1 shows in schematic plan view an example of a sole
according to the first, second and third embodiments of the present invention.
Figure 2 shows in schematic perspective view the sole of figure 1.
Figure 3a shows a schematic side view of the sole of figure 1
according to an example of the first embodiment of the invention.
Figure 3b shows a schematic perspective view of a longitudinal
pronation guiding element as included in the sole of figure 3a.
Figure 4a shows a schematic side view of the sole of figure 1
according to an example of a second embodiment of the invention.
Figure 4b shows a schematic side view of the sole of figure 1
according to an example of a third embodiment of the invention .$
Figure 4c shows a schematic perspective view of a longitudinal
pronation guiding element as included in the sole of figure 4a or 4b.
Figures 5a to 51 show in schematic cross section some example
profiles for the longitudinal pronation guiding element.
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It should be noted that the drawings are provided in order to aid an
understanding of the invention. They should not be taken to imply any
limitation
on the scope of protection sought, which is set out in the accompanying
claims.
Where the same reference numbers have been used in different figures, these
are intended to refer to the same or corresponding features. However, the use
of different reference numbers is not necessarily intended to indicate a
difference between the features to which they refer.
The general principles of the invention will now be described with
reference to figures 1 and 2, which show in highly schematic form a sole, 1,
for
a right foot. The sole is shown with a midsole body element, 3, which may be
an essentially planar piece of relatively soft elastomeric sheet, for example
having a durometer of between 30 and 50 Shore. Such a midsole body
element, 3, may have a thickness of between 5mm and 30mm, for example. In
the upper surface of the midsole body element, 3, is shown an example of a
longitudinal pronation guiding element, 2. The longitudinal pronation guiding
element, 2, may have a constant thickness, as will be described later, or it
may
be of different thickness in different regions. The longitudinal pronation
guiding
element, 2, may be formed as a separate piece of elastomeric material, for
example, and inserted into a correspondingly shaped recess in the upper
surface of the midsole body element, 3, or it may be formed in the same
process, such as injection moulding, as the surrounding material of the
midsole
body element, 3, but with a higher durometer. The durometer of the
longitudinal
pronation guiding element, 2, may for example be between 55 and 80.
Various different regions of the longitudinal pronation guiding
element, 2, and, by extension, of the sole, are indicated in figures 1 and 2
by
way of example: the heel region 6, the mid-foot region 7, the ball region 8
and
the toe region 9. In addition, a dotted line, 10, indicates an ideal
longitudinal
proprioception axis. In the heel and mid-foot regions 6 and 7, the
proprioception axis is well to the lateral side of the sole, and the "correct"
amount of pronation is low across these regions. In the ball and toe regions,
by
contrast, the proprioception axis moves across to the medial side of the sole,
and the "correct" amount of pronation is higher in these regions. Due to its
extra hardness, compared to the hardness of the surrounding midsole body
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element, 3, the longitudinal pronation guiding element, 2, is easily sensed by
the sole of the wearer's foot, and the information about the transverse
position
of each portion of the longitudinal pronation guiding element, 2, can be used
by
the wearer's gross motor locomotion system to adjust the pronation of the foot
5 in response, thereby achieving the desired proprioception described above.
Figure 1 also shows a transverse axis M-L running from the M
(medial) side to the L (lateral) side of the sole. This axis will be referred
to
below when describing various examples of possible cross-sections of the
longitudinal pronation guiding element 2.
10 In preferred embodiments of the invention, the longitudinal
pronation
guiding element 2 can have a thickness and/or hardness which varies along
the transverse direction (parallel to the M-L axis), at least in the heel
and/or ball
regions, in order to give increased pronation control. Thus, in the heel
region 6,
the longitudinal pronation guiding element 2 is made thicker on the medial
side
than on the lateral side. In this way, the transverse profile of the heel
region 6
of the longitudinal pronation guiding element, 2, contributes to the desired
pronation-resisting (or supination-promoting) effect which is desired in the
heel
region of the sole. In the ball region, by contrast, the opposite effect is
desired.
Medial and lateral pronation control elements (4 and 5) are also
shown in figures 1 and 2. These may be used in addition to the longitudinal
pronation guiding element, 2, to provide additional correction of pronation
and
supination as required at different points along the length of the sole. In
the
example shown, the medial pronation control element 4 may essentially be a
region of increased hardness which offers an increased pressure force to
resist
the pronation of the wearer's foot at the beginning of the contact phase with
the
ground (ie while much of the wearer's weight is on the heel and being
transferred to the mid-sole portion 7). The lateral pronation control element
5 is
designed to have the opposite effect (ie to increase pronation) at a point
further
forward along the sole. The lateral pronation control element 5 can also be
formed as a region of increased hardness in the material of the midsole body
element 3. Its function is to assist the foot in pronating at the point in the
step
cycle when the wearer's weight is being transferred to the ball of the foot.
At
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this point the line of optimal pronation, 10, crosses over from the lateral
side to
the medial side of the sole, in the ball region indicated as 8 in figure 1.
Note that the medial and lateral pronation control elements 4 and 5
may alternatively be formed as separate elements and then bonded or
otherwise attached to the side of the midsole body element 3. In order to give
the required pronation control effect, they should be of a harder material
than
the midsole body element 3.
By way of example, the relative hardnesses of the various sole
components may be configured as follows:
The midsole body element, 3, may have a hardness in the range 30-
50 Shore.
The medial pronation control element 4 may have a hardness in the
range 45 to 65 Shore. Its hardness is in any case greater than that of the
midsole body element 3, and preferably greater or equal to the hardness of the
lateral pronation control element, 5.
The lateral pronation control element 5 may have a hardness in the
range 40-60 Shore, but in any case greater than that of the midsole body
element, 3.
The longitudinal pronation guiding element 2 may have a hardness
in the range 55 to 80 Shore, but in any case greater than that of the lateral
and
medial pronation control elements 4, 5.
Figure 3a shows an example of a longitudinal cross section taken
along the longitudinal pronation axis 10 of figures 1 and 2. In this first
example
embodiment, the longitudinal pronation guiding element 2 has a substantially
rectangular transverse cross-section, corresponding to the shape shown in
figure 5b. The sole 1 is shown with an outsole 11 on the ground-facing side of
the midsole body element 3. Figure 3b shows such a longitudinal pronation
guiding element 2 in perspective view.
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Figures 4a to 4c show examples of alternative embodiments in which
the longitudinal pronation guiding element, 2, is thicker in the mid-foot
region 7,
to form a region 7' of harder material than the surrounding midsole body
element 3. This region 7' is also referred to as a gait enhancement element,
and its purpose is to enhance the transfer of the wearer's weight from the
relatively softer heel region 6 of the sole 1, in the initial contact phase of
the
foot with the ground, over the harder mid-foot region 7' to the softer ball
region
8 of the sole 1.
The harder thickened portion 7' may extend down to make contact
the outsole 11, as shown in figure 4a, or it may merely be a thickening of the
longitudinal pronation guiding element, 2, which only extends part way into
the
midsole body element 3 (not shown in the figures).
The gait enhancement element 7' is shown in figures 4a and 4b as
being contiguous with the longitudinal pronation guiding element, 2. However,
the gait enhancement element 7' may alternatively be formed as a separate
element formed or inserted below the longitudinal pronation guiding element,
2.
It may also have a different durometer from both the longitudinal pronation
guiding element, 2, and the midsole body element 3.
In the example third embodiment shown in figure 4b, the gait
zo enhancement element 7' extends all the way through the midsole body
element
3 and through an opening in the outsole element 11.
As a result of the increased hardness of the longitudinal pronation
control element 2, relative to the softer material of the surrounding midsole,
3,
the wearer will feel more pressure and support from points located on this
proprioception line than from points located off the proprioception line.
Whenever the person shifts his/her dynamic force vector resulting from the
static weight and the dynamic force during the rolling action of each foot
such
that this dynamic vector no longer passes through this protruding line, the
wearer will experience the desired feedback during standing, walking or
running whenever the foot senses a deviation from the proprioception line of
optimal ground contact.
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As illustrated in figure 5a, the longitudinal pronation control element
2 may have a trapezoidal cross-section, for example. Other potential cross-
section profiles are shown in figures 5b to 5i.
Figures 5d and 5e show variants in which the lower surface of the
longitudinal pronation control element, 2, is concave, thereby amplifying the
proprioception effect of deviating from the main proprioception line of
optimal
ground contact.
Figures 5f to 5i show variants in which the cross-section of the
longitudinal pronation control element, 2, is wedge-shaped or tapering. The
thickness of the longitudinal pronation control element, 2, may thus decrease
from the lateral side toward the medial side or vice-versa. As a result, when
wearing such a sole during walking or running, the foot's line of maximum
contact pressure with the ground will be shifted transversely (from medial to
lateral or vice versa). The longitudinal pronation control element, 2, may be
made thicker on the lateral side than on the medial side, for example, which
can correct the gait of a bow-legged person. Or the longitudinal pronation
control element, 2, may be made thicker toward the medial side, in which case
it may be used for correcting the gait of a knock-kneed person.
Note that the figures show the longitudinal pronation control
element, 2, as being flush with the upper surface of the midsole body element,
3. However, the longitudinal pronation control element, 2, may also be
arranged such that its is proud of the surface of the surrounding midsole body
element, 3 (by a height of 0.5 to 3mm, for example). By arranging the harder
longitudinal pronation control element, 2, to protrude from the softer midsole
element, 3, in this way, the proprioception effect can be greatly enhanced.
Alternatively, the longitudinal pronation control element, 2, may be
recessed or submerged into the surrounding material of the midsole body
element. In this case, the proprioception can be softened somewhat.
Note that the harder longitudinal pronation control element, 2, must
not necessarily be less flexible than the surrounding midsole element. It is
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advantageous to make the longitudinal pronation control element, 2, harder,
but more flexible, than the midsole element, so that the foot's contact path
(pronation path) can be guided by predetermining the line of increased
pressure (optimal contact line), but without reducing the longitudinal
flexibility
of the sole.
In one preferred embodiment, the heel region 6 of the longitudinal
pronation control element may be made thicker on the medial side than on the
lateral side, so as to resist overpronation in the initial ground-contact
phase of
the gait, when the wearer's weight is principally on the heel.
In another preferred embodiment, the ball portion 8 of the
longitudinal pronation control element, 2, has first, second, third, fourth
and fifth
metatarsal regions counting from the medial side M to the lateral side L of
the
sole, and the thickness and/or hardness of the longitudinal pronation control
element, 2, may be configured to increase from the first to fifth metatarsal
regions.
As a result, when a foot rolls on the ground with the sole of the foot
contacting the ground in sequence by its heel, midfoot, ball and forefoot
portions, the above thickness and/or hardness gradient in the ball portion
causes the foot to pronate, ie the weight acting on the foot is shifted from
its
initial position in the midfoot portion at the lateral side L of the sole to
the
subsequent position in the ball portion at the medial side M. In other words,
the
foot is encouraged into pronation while the ball portion of the foot and the
sole
are rolling on the ground. Thus, during a first phase of the foot's rolling on
the
ground, the weight acting on the lateral side of the midfoot portion and then
on
the lateral side of the ball portion is shifted from the lateral side of the
ball
portion toward the medial side of the ball portion, and during a second phase
of
the foot's rolling on the ground, the weight then acts on the medial side of
the
ball portion and then on the medial side of the forefoot portion, ie the big
toe.
These conditions of the first, second, third, fourth and fifth metatarsal
parts in the ball portion of the sole cause the weight during the rolling
action of
the foot to be shifted form the lateral side L towards the medial side M.
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More precisely, after the midfoot portion has rolled on ground with
the weight located on the lateral side L, the ball portion then rolls on the
ground
with the weight being shifted from the lateral side L of the ball portion
toward
the medial side M of the ball portion, and finally the forefoot portion rolls
on the
5 ground with the weight located on the medial side M. At the beginning of
this
shifting action within the ball portion, the fifth metatarsal part of the ball
portion
provides more support than the neighboring fourth and third metatarsal parts
of
the ball portion. At the end of this shifting action within the ball portion,
the first
metatarsal part of the ball portion provides more support than the second
10 metatarsal part of the ball portion. In other words, the fifth
metatarsal part on
the lateral side L causes the foot to pronate and the first metatarsal part on
the
medial side M prevents excessive pronation of the foot.
Thus, these conditions of the first, second, third, fourth and fifth
metatarsal parts in the ball portion of the sole have an effect similar to two
15 consecutive banked curves placed along the substantially S-shaped line.
Using
these terms, during the right foot's rolling action along the substantially S-
shaped line, the right foot first passes through a banked curve with a left
turn at
the lateral side L and then through a banked curve with a right turn at the
medial side M. Similarly, during the left foot's rolling action along the
zo substantially S-shaped line, the left foot first passes through a banked
curve
with a right turn at the lateral side L and then through a banked curve with a
left
turn at the medial side M.
A similar thickness and/or hardness gradient may be created in the
forefoot portion or toe portion of the sole. In this way, the region of the
sole
associated with or underneath the second toe (T2) may be configured with a
lesser thickness and/or hardness than the region of the sole associated with
or
underneath any of the first, third, fourth and fifth toes. Preferably, this
applies to
the part of the forefoot or toe portion adjacent to the ball portion. This
concave
("cantilever") and/or soft region in the M2 part of the ball portion and
optionally
in the T2 part of the adjoining forefoot portion provides some pressure relief
for
the second metatarsal bone.
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In summary, it should be noted that the amount of local support, ie
the local support forces acting from below on the sole of a foot wearing the
sole
according to the invention, is determined by the overall thickness and/or
hardness profile of the sole. At least the midsole body element and the ground-
contacting portions (outsole) contribute with their local hardnesses and local
geometries, for instance local thickness distribution and distribution of
possible
slits, to the resulting amount of local support. In addition, the lower and/or
upper insole portions may be provided with their additional contribution to
the
resulting amount of local support. The ground-contacting portions (heel,
midfoot, ball and forefoot portions) and the optional insole portions (lower
and/or upper insole portion) of the sole all contribute additionally to the
support
profile defined by the longitudinal pronation control element, 2, extending
along
the substantially S-shaped line.
A cantilever profile, such as the one shown in Fig. 5d or in Fig. 5e,
may be provided in the the ball portion 8 and the forefoot portion 9 of the
sole
1. The region of the sole 1 associated with the second metatarsal bone (M2)
has a lesser thickness and/or lesser hardness than the region of the sole
associated with the other metatarsal bones. In addition, at least the part of
the
forefoot portion 9 or toe portion of the sole adjacent to the ball portion 8,
ie the
region of the sole 1 associated with the second toe (T2) has a lesser
thickness
and/or lesser hardness than the region of the sole associated with the other
toes. Preferably, this applies to the toe portion of the forefoot portion 9.
This
design reduces pressure to the second metatarsal (M2) and provides some
relief for the joint between the second metatarsal (M2) and the second toe
(T2)
during walking.
In addition, the following conditions may apply to the transverse
thickness and/or hardness profile of the ball portion 8 having a first
metatarsal
part Ml, a second metatarsal part M2, a third metatarsal part M3, a fourth
metatarsal part M4 and a fifth metatarsal part M5 between the medial side M
and lateral side L of the sole 1:
a) The thickness and/or hardness of M2 is less than the thickness and/or
hardness of any of Ml, M2, M3 and M4, preferably with Ml, M3, M4 and M5 all
having the same thickness and/or hardness.
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("M2 < Ml, M3, M4, M5 and preferably M1 = M3 = M4 = M5")
b) The thickness and/or hardness of M1 is greater than the thickness and/or
hardness of M2, with M3, M4 and M5 all having a thickness and/or hardness in
between the thickness and/or hardness of M1 and M2.
("M2 < M3, M4, M5 < Ml")
c) The thickness and/or hardness of M1 is greater than the thickness and/or
hardness of M2, with M3, M4 and M5 all having a thickness and/or hardness
greater than the thickness and/or hardness of Ml.
("M2 < M1 <M3, M4, M5")
to d) The thickness and/or hardness of M1 is greater than the thickness
and/or
hardness of M2, with M3 having a thickness and/or hardness greater than the
thickness and/or hardness of M4 and M4 having a thickness and/or hardness
greater than the thickness and/or hardness of M5.
("M2 < M1 and M3> M4 > M5")
e) The thickness and/or hardness of M1 is greater than the thickness and/or
hardness of M2, with M3 having a thickness and/or hardness less than the
thickness and/or hardness of M4 and M4 having a thickness and/or hardness
less than the thickness and/or hardness of M5, preferably with M2 having a
thickness and/or hardness less than the thickness and/or hardness of any of
M3, M4 and M5. Condition e) is the most preferred condition.
("M2 < M1 and M3 < M4 and M4 < M5" and preferably M2 < M3, M4, M5")
These conditions of the first, second, third, fourth and fifth metatarsal
parts Ml, M2, M3, M4 and M5 in the ball portion 5 of the sole 1 cause the
weight during the rolling action of the foot to be shifted form the lateral
side L
towards the medial side M.
More precisely, after touching ground with the heel portion 3 and the
subsequent rolling action of the midfoot portion 7 on ground with the weight
located on the lateral side L, the ball portion 8 then rolls on the ground
with the
weight being shifted from the lateral side L of the ball portion 8 toward the
medial side M of the ball portion 8, and finally the forefoot portion 9 rolls
on the
ground with the weight located on the medial side M. At the beginning of this
shifting action within the ball portion 8, the fifth metatarsal part M5 of the
ball
portion 8 provides more support than the neighboring fourth and third
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metatarsal parts M4 and M3 of the ball portion 8. At the end of this shifting
action within the ball portion 8, the first metatarsal part M1 of the ball
portion 8
provides more support than the second metatarsal part M2 of the ball portion
8.
Thus, the fifth metatarsal part M5 on the lateral side L causes the foot to
pronate and the first metatarsal part M1 on the medial side M prevents
excessive pronation of the foot.
In addition, similar conditions may apply to the transverse thickness
and/or hardness profile of the forefoot portion 6 having a first toe part Ti,
a
second toe part T2, a third toe part 13, a fourth toe part T4 and a fifth toe
part
T5 between the medial side M and lateral side L of the sole 1:
a) The thickness and/or hardness of Ti is greater than the thickness and/or
hardness of any of T2, T3, T4 and T5, preferably with T2, T3, T4 and T5 all
having the same thickness and/or hardness.
("Ti > T2, T3, T4, T5 and preferably T2 = T3 = T4 = 15")
b) The thickness and/or hardness of Ti is greater than the thickness and/or
hardness of T2 and the thickness and/or hardness of T2 is greater than the
thickness and/or hardness of T3, and the thickness and/or hardness of 13 is
greater than the thickness and/or hardness of T4, and the thickness and/or
hardness of 14 is greater than the thickness and/or hardness of T5.
("T1 > T2 > T3 > 14 > T5")
c) The thickness and/or hardness of Ti is less than the thickness and/or
hardness of any of T2, T3, T4 and 15, preferably with T2, T3, 14 and T5 all
having the same thickness and/or hardness.
("Ti <T2, T3, T4, T5 and preferably T2 = 13 = T4 = T5")
d) The thickness and/or hardness of Ti is less than the thickness and/or
hardness of T2, and the thickness and/or hardness of 12 is less than the
thickness and/or hardness of T3, and the thickness and/or hardness of T3 is
less than the thickness and/or hardness of T4, and the thickness and/or
hardness of T4 is less than the thickness and/or hardness of T5.
("Ti <T2 <T3 <T4 <T5")
e) The thickness and/or hardness of Ti is greater than the thickness and/or
hardness of T2, with 12 having the same thickness and/or hardness as T3, and
the thickness and/or hardness of 13 is less than the thickness and/or hardness
of T4, with the thickness and/or hardness of T4 being equal or less than the
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thickness and/or hardness of T5.
('Ti > T2 and T2 = T3 and T3 <T4 and T4 <T5")
In the above transverse profiles, the transition between the thickness
and/or hardness sections Ml, M2, M3, M4, M5 and Ti, T2, T3, T4, T5,
respectively, may be a stepwise or a smooth transition.
The longitudinal pronation guiding element, 2, can be solid
elastomeric material, or it can be a moulded or hollow shape filled with loose
material such as a granulate or powder material.
