U.S. patent application number 12/249741 was filed with the patent office on 2009-10-01 for skate boot.
This patent application is currently assigned to DASC, LLC. Invention is credited to David CRUIKSHANK, Scott VAN HORNE.
Application Number | 20090243238 12/249741 |
Document ID | / |
Family ID | 40549612 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090243238 |
Kind Code |
A1 |
VAN HORNE; Scott ; et
al. |
October 1, 2009 |
SKATE BOOT
Abstract
A skate boot includes a foot portion configured to receive and
secure a foot of a wearer. The skate boot includes a first tendon
guard positioned proximal an Achilles tendon of a wearer of the
skate boot, the first tendon guard being connected to the foot
portion at a first articulation point and adjacent the foot portion
along a medial abutment line and a lateral abutment line. The skate
boot may optionally include a second tendon guard connected to the
foot portion at a second articulation point and to the first tendon
guard, the second tendon guard covering the first articulation
point. In at least one embodiment, an elastomeric band is connected
to the foot portion and to the first tendon guard and configured to
bias the first tendon guard to a closed position. In at least one
embodiment, an electrical generator is provided to heat an ice
skate interconnected to the boot.
Inventors: |
VAN HORNE; Scott; (Calgary,
CA) ; CRUIKSHANK; David; (Delafield, WI) |
Correspondence
Address: |
HOLME ROBERTS & OWEN LLP
1700 LINCOLN STREET, SUITE 4100
DENVER
CO
80203
US
|
Assignee: |
DASC, LLC
Las Vegas
NV
|
Family ID: |
40549612 |
Appl. No.: |
12/249741 |
Filed: |
October 10, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60978758 |
Oct 10, 2007 |
|
|
|
Current U.S.
Class: |
280/11.12 ;
36/115 |
Current CPC
Class: |
A43B 7/04 20130101; A43B
5/16 20130101; A43C 11/002 20130101 |
Class at
Publication: |
280/11.12 ;
36/115 |
International
Class: |
A43B 5/16 20060101
A43B005/16; A63C 1/02 20060101 A63C001/02 |
Claims
1. A skate boot, comprising: a foot portion configured to receive
and secure a foot of a wearer; an articulating tendon guard
positioned proximal an Achilles tendon of the wearer of the skate
boot, the articulating tendon guard being connected to the foot
portion at an articulation point and adjacent the foot portion
along a medial abutment line and a lateral abutment line; and an
elastomeric member connected to the articulating tendon guard and
connectable to a lower leg of the wearer; and an elastomeric band
connected to the foot portion and to the articulating tendon guard
and configured to bias the articulating tendon guard to a closed
position where the articulating tendon guard abuts the foot portion
long the medial abutment line and the lateral abutment line.
2. A skate boot, comprising: a foot portion configured to receive
and secure a foot of a wearer; a first tendon guard positioned
proximal an Achilles tendon of a wearer of the skate boot, the
first tendon guard being connected to the foot portion at a first
articulation point and adjacent the foot portion along a medial
abutment line and a lateral abutment line; a second tendon guard
connected to the foot portion at a second articulation point and to
the first tendon guard, the second tendon guard covering the first
articulation point; and an elastomeric band connected to the foot
portion and to the first tendon guard and configured to bias the
first tendon guard to a closed position where the first tendon
guard abuts the foot portion long the medial abutment line and the
lateral abutment line.
3. An ice skate, comprising: a foot portion configured to receive
and secure a foot of a wearer; a first tendon guard positioned
proximal an Achilles tendon of the wearer of a skate boot, the
first tendon guard being connected to the foot portion at a first
articulation point and adjacent the foot portion along a medial
abutment line and a lateral abutment line; a second tendon guard
connected to the foot portion at a second articulation point and
adjacent to the first tendon guard, the second tendon guard
covering the first articulation point; and an elastomeric band
connected to the foot portion and to the first tendon guard and
configured to bias the first tendon guard to a closed position
where the first tendon guard abuts the foot portion long the medial
abutment line and the lateral abutment line an electrical
generator, comprising: a first electrical generation component
connected to the first tendon guard; a second electrical generation
component connected to the second tendon guard, wherein movement of
a leg of the wearer forwards and backwards moves the first
electrical generation component with respect to the second
electrical generation component, thereby generating an electrical
current; the ice skate connected to the skate boot; and a plurality
of resistors connected to the ice skate and configured to receive
the electrical current from the electrical generator to thereby
generate heat and heat the ice skate.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of U.S.
Provisional Patent Application No. 60/978,758 filed on Oct. 10,
2007, entitled "Skate Boot," the entire disclosure of which is
incorporated herein by reference in its entirety for all
purposes.
FIELD
[0002] The present invention relates generally to ice skates and
more specifically to the construction of the rigid support
component of the skate boot, traditionally referred to as the sole
and counter of the boot.
BACKGROUND
[0003] Skating locomotion is based on propulsion through a glide
technique. The skate blade that is performing the push glides at a
right angle to the direction of the push force (Boer et al., 1986;
Boer et al., 1989; van Ingen Schenua et al., 1980; van Ingen
Schenua et al., 1985, van Ingen Schenua at al., 1987). This causes
the trajectory of the body to look like a sine wave (Boer et al.,
1986; Deloij et al., 1986). The motion of one leg during skating
involves a glide phase, a push phase, and a recovery phase
(Allinger and Motl, 2000). The push phase is the only phase where
the generation of velocity occurs.
[0004] Nothing herein is to be construed as an admission that the
present invention is not entitled to antedate a publication by
virtue of prior invention. Furthermore, the dates of publication
where provided are subject to change if it is found that the actual
date of publication is different from that provided here.
SUMMARY
[0005] One or more inventions are described herein. In one
embodiment, a skate boot is provided that includes a foot portion
configured to receive and secure a foot of a wearer. The skate boot
includes a first tendon guard positioned proximal an Achilles
tendon of a wearer of the skate boot, the first tendon guard being
connected to the foot portion at a first articulation point and
adjacent the foot portion along a medial abutment line and a
lateral abutment line. The skate boot may optionally include a
second tendon guard connected to the foot portion at a second
articulation point and to the first tendon guard, the second tendon
guard covering the first articulation point. In at least one
embodiment, an elastomeric band is connected to the foot portion
and to the first tendon guard and configured to bias the first
tendon guard to a closed position. In at least one embodiment, an
electrical generator is provided to heat an ice skate
interconnected to the skate boot.
[0006] It is to be understood that the present invention includes a
variety of different versions or embodiments, and this Summary is
not meant to be limiting or all-inclusive. This Summary provides
some general descriptions of some of the embodiments, but may also
include some more specific descriptions of certain embodiments. As
used herein, "at least one", "one or more", and "and/or" are
open-ended expressions that are both conjunctive and disjunctive in
operation. For example, each of the expressions "at least one of A,
B and C", "at least one of A, B, or C", "one or more of A, B, and
C", "one or more of A, B, or C" and "A, B, and/or C" means A alone,
B alone, C alone, A and B together, A and C together, B and C
together, or A, B and C together.
[0007] It is to be noted that the term "a" or "an" entity refers to
one or more of that entity. As such, the terms "a" (or "an"), "one
or more" and "at least one" can be used interchangeably herein. It
is also to be noted that the terms "comprising", "including", and
"having" can be used interchangeably.
[0008] Various embodiments of the present invention are set forth
in the attached figures and in the detailed description of the
invention as provided herein and as embodied by the claims. It
should be understood, however, that this Summary does not contain
all of the aspects and embodiments of the present invention, is not
meant to be limiting or restrictive in any manner, and that the
invention as disclosed herein is and will be understood by those of
ordinary skill in the art to encompass obvious improvements and
modifications thereto.
[0009] Additional advantages of the present invention will become
readily apparent from the following discussion, particularly when
taken together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] To further clarify the below and other advantages and
features of the present invention, a more particular description of
the invention will be rendered by reference to specific embodiments
thereof which are illustrated in the appended drawings. It is
appreciated that these drawings depict only typical embodiments of
the invention and are therefore not to be considered limiting of
its scope. The invention will be described and explained with
additional specificity and detail through the use of the
accompanying drawings in which:
[0011] FIG. 1A illustrates an embodiment of an articulating tendon
guard from a sagittal view according to one embodiment of the
invention.
[0012] FIG. 1B is a rear view of the articulating tendon guard
illustrated in FIG. 1A.
[0013] FIG. 2A is a top view of the primary tendon guard and
neoprene strap of the embodiment of FIG. 1A.
[0014] FIG. 2B is a sagittal view of the primary tendon guard and
neoprene strap of the embodiment of FIG. 1A.
[0015] FIG. 3A illustrates a an articulating tendon guard from a
sagittal view according to a further embodiment of the
invention.
[0016] FIG. 3B is a rear view of the articulating tendon guard
illustrated in FIG. 3A.
[0017] FIG. 3C is another sagittal view of the embodiment of FIG.
3A. In FIG. 3C the skate boot is illustrated with the tendon guards
in an ankle plantar flexed position.
[0018] FIG. 4A illustrates an articulating tendon guard according
to another example embodiment of the invention.
[0019] FIG. 4B is a sagittal view of the articulating tendon guard
of FIG. 4A with the tendon guards in an ankle plantar flexed
position.
[0020] FIG. 4C is a sagittal view of the articulating tendon guard
of FIG. 4A with the tendon guards in an ankle dorsi flexed
position.
[0021] FIG. 5 is a photograph of the Graf Supra 703 (left), and the
CCM 952 Super Tacks (right), showing maximal ankle extensions
(plantar flexion). The ankle joint axis is marked by dot 18, and
the knee joint axis is marked by a dot 19.
[0022] FIG. 6 is a photograph of the Graf Supra 703 modified for
the ankle extension (left), and the CCM 952 Super Tacks modified
with a removed upper tendon guard (right), showing maximal ankle
extension (plantar flexion). The ankle joint axis is marked by a
dot 18, and the knee joint axis is marked by a dot 19.
[0023] FIG. 7 is a photograph of a bare foot showing three
successive ankle extension positions. The ankle axis of rotation is
marked by a dot 18.
[0024] FIG. 8 is a photograph of a VH stock custom speed skate
showing maximal ankle extension (plantar flexion). The ankle joint
axis is marked by a dot 18, and the knee joint axis is marked by a
dot 19.
[0025] FIG. 9 is a schematic of a speed skating push with the pivot
point positioned in the same place as the end of the hockey skate
blade, and a schematic of a hockey skating push. Rigid links were
created between the hip joint, knee joint, ankle joint, and the
point where rotation of the foot occurs (pivot point) for
biomechanical analysis.
[0026] FIG. 10 is photographs showing the data collection set up in
the laboratory.
[0027] FIG. 11 is a graph showing the final center of mass velocity
for a simulated skating push with a conventional hockey skate and
the ankle extension skate. Data presented are averages with 95%
confidence intervals for ten subjects.
[0028] FIG. 12 is a graph showing the ankle energy generated during
the explosive push phase for a simulated skating push with a
conventional hockey skate and the ankle extension conversion skate.
Data presented are averages with 95% confidence intervals for ten
subjects.
[0029] FIG. 13 is a diagram of the gliding direction of the pushing
skate, final CM velocity vector, and the component of the CM
velocity vector in the direction of forward motion for the ankle
extension conversion skate and the traditional hockey skate.
[0030] FIG. 14 is a diagram representing the movement of two
hypothetical hockey players skating maximally towards a puck 12.27
m away. Player 1 represents a player wearing the ankle extension
conversion skate. Player 2 represents a player wearing a
traditional hockey skate.
[0031] FIG. 15 is photographs of the Graf Supra 703 unmodified, and
modified for the ankle extension, during maximal eversion and
inversion of the ankle joint. Photographs were taken from the
frontal view. The center of the ankle joint axis is marked by a dot
18, and the center of the knee joint axis is marked by a dot
19.
DETAILED DESCRIPTION
[0032] Reference will now be made to the drawings to describe
various aspects of exemplary embodiments of the invention. It is to
be understood that the drawings are diagrammatic and schematic
representations of such exemplary embodiments, and are not limiting
of the present invention, nor are they necessarily drawn to
scale.
[0033] In the following description, numerous specific details are
set forth in order to provide a thorough understanding of the
present invention. It will be obvious, however, to one skilled in
the art that the present invention may be practiced without these
specific details. In other instances, well-known aspects of skate
boots have not been described in particular detail in order to
avoid unnecessarily obscuring the present invention.
[0034] With reference now to FIGS. 1A and 1B, according to a first
example embodiment of the invention an articulating tendon guard
uses a neoprene lower leg strap 5 to connect the articulating
tendon guard to the lower leg of a wearer. In one embodiment the
skate boot has two cuts 2 angled distally towards the ankle axis of
rotation, forming the tendon guard 1 between them. The two cuts
meet approximately 20 mm shy of each other at the point of
articulation 3. The point of articulation is along the same
horizontal axis as the ankle joint center and therefore allows
complete unrestricted plantar flexion of the ankle joint. An
elastomeric band 4 is inserted between the inner and outer layers
of the upper and sewn in place. The elastomeric band 4 crosses the
cut 2 and provides recoil of the tendon guard 1, after ankle
extension. Also, to ensure adequate recoil of the tendon guard 1 a
lower leg strap 5, which may be made of neoprene for example, is
preferably adhered and stitched 6 to the tendon guard. In one
embodiment the strap 5 fastens to the lower leg by a hook and loop
attachment 7 on the anterior side of the leg (shin), as illustrated
in FIGS. 2A and 2B.
[0035] In one example embodiment of the invention the tendon guard
is formed by modifying an existing skate boot by cutting the skate
boot at cuts 2 and adding the lower leg strap 5 and elastomeric
band 4. In another example embodiment the tendon guard is formed
separately from the skate boot and attached thereto at articulation
point 3 by a method known in the art of connecting the selected
materials.
[0036] Another example embodiment of the invention is illustrated
in FIGS. 3A, 3B, and 3C. In this embodiment a lower leg strap 5 may
optionally be omitted while a secondary tendon guard 10 is added to
help protect the articulation 3 of the primary tendon guard 1. The
secondary tendon guard 10 is also preferably biased to assist in
recoil of the primary tendon. The secondary tendon guard 10
articulates at a point 8 that is between 1 cm and 5 cm below the
articulation of the primary tendon guard 3. The secondary tendon
guard 10 is attached to the primary tendon guard 1 at point 9 with
a connector such as a rivet, bolt and t-nut, and the like.
[0037] With reference now to FIGS. 4A-4C, in yet another example
embodiment of the invention electrical generation components are
added to moving parts in the skate boot so that current can be
conducted to the blade where resisters will convert the electric
current into heat. It has been shown that heated blades glide
50-75% better than non-heated blades due to reduced ice friction.
Electrical generation component 12 generates a current when
component 13 slides over it as the tendon guards are extended and
then recoiled. Electrical generation component 15 also generates a
current when component 14 slides over it as the tongue is flexed
forward and then recoiled. The current that is generated is
conducted along the wire 16 and is converted into heat by the
resistors 17 that lie in small recesses in the skate blade.
[0038] The following Performance Comparison describes attributes of
an embodiment of the present invention in comparison to another
device.
Performance Comparison
[0039] 1. Biomechanical and Performance Aspects of a Skate in
Accordance with at least one Embodiment of the Present
Invention
[0040] The Performance Comparison looked at the performance effects
of increasing ankle joint range of motion during the skating push
with certain modifications to the tendon guard (ankle extension).
The purposes of this investigation were:
[0041] To compare the total amount of push energy and center of
mass velocity generated during a skating push with the constraints
of a conventional hockey skate versus that with the reduced
constraints of a hockey skate that incorporates the new ankle
extension. These results will then be related to actual skating
kinematics.
[0042] To determine if the ankle extension has any deleterious
effects on ankle support, stability, and protection.
[0043] Data collection consisted of two parts. The first part was a
detailed analysis of angular energetics and center of mass movement
during the push phase of a simulated skating push. Data were
collected on ten subjects in the laboratory while the subjects
performed a maximal effort skating push on a modified slide board
apparatus. The second part of the investigation consisted of two
case studies that tested prototypes of the ankle extension, on the
ice. The case studies involved digital picture analysis of ankle
inversion and eversion, along with anecdotal feedback.
[0044] The lab testing indicated that there was a strong positive
influence, of the increased ankle range of motion allowable with
the ankle extension, on skating performance. It was shown that the
increased energy generation per push resulted in a higher final
velocity of the center of mass during the push phase. It was
further shown that the increased velocity would have a significant
effect on hockey skating performance.
[0045] The case studies revealed no decrease in ankle support and
stability, with positive anecdotal feedback relating to the
matter.
2. Introduction
[0046] The skate boot embodiment analyzed in this testing has a
tendon guard that allows a much larger range of motion at the ankle
joint than what is currently allowed with conventional hockey skate
boots. The ankle extension allows for a larger range of motion
through increased ankle extension. It was speculated that this
increased ankle joint extension would result in higher energy
generation and a slight elongation of the push, resulting in
increased acceleration and maximal skating velocity.
[0047] Purpose
[0048] To compare the total amount of push energy and center of
mass velocity generated during a skating push with the constraints
of a conventional hockey skate versus that with the reduced
constraints of a hockey skate that incorporates the new ankle
extension. These results will then be related to actual skating
kinematics.
[0049] To determine if the ankle extension has any deleterious
effects on ankle support and stability.
3. Methods
[0050] Data collection consisted of two parts. The first part was a
detailed analysis of angular energetics and center of mass movement
during the push phase of a simulated skating push. The second part
of the investigation consisted of two case studies.
Skates
[0051] The hockey skates analyzed were the Graf Supra 703 and the
CCM 952 Super Tacks. All skates were commercially available and
modified for analysis after purchase. The Graf Supra 703 skates
were initially analyzed for maximal extension angle (FIG. 5), and
subsequently modified for the ankle extension and tested for
maximal extension angle (FIG. 6). The CCM 952 Super Tacks were
initially analyzed for maximal extension angle (FIG. 5), and
subsequently modified for an increased range of motion (FIG. 6), to
mimic what has been done commercially to allow for increased ankle
extension (i.e. Graf727, Bauer Supremes, Mission Super Fly). An
uninhibited foot was analyzed for anatomical extension
characteristics (FIG. 7). A VH Stock Custom speed skate boot was
also analyzed for maximal extension angle to provide accurate
comparison information between the collected data and the hockey
skates (FIG. 8).
[0052] FIG. 5 shows an ankle extension angle of 106.5.degree.. This
angle was believed to be the common extension angle with
conventional hockey skates. FIG. 6 shows an extension angle of
122.degree. for the ankle extension. Even in FIG. 6 where the upper
tendon guard is removed from CCM 952 Super Tacks an extension angle
of only 110.5.degree. could be achieved. The reason for the
11.5.degree. larger extension angle can be clearly seen in FIG. 7,
where rotation occurs through the ankle axis. The ankle axis of
rotation runs approximately through the malleoli (ankle bones). It
can be clearly seen that any rigid structure extending vertically
above the ankle axis will inhibit ankle extension, and prematurely
end the skating push. Therefore, even with the upper tendon guard
cut (FIG. 6) the lower portion of the tendon guard is still too
high to allow full ankle range of motion. With the ankle extension
the cut in the tendon guard is angled distally towards the ankle
axis of rotation, allowing for a less inhibited ankle extension,
and a longer skating push. FIG. 8 shows an ankle extension angle of
137.degree., the maximum allowable with a speed skate. This
information was used to extrapolate a skating push with a
conventional hockey skate and a hockey skate with the ankle
extension from the data.
Subjects
[0053] A total of ten male subjects participated in this study. All
subjects were elite level speed skaters. All subjects were free
from recent lower extremity injury or pain. Informed written
consent in accordance with the University of Calgary's Research
Ethics Board was obtained from all subjects.
Angular Energetics and Center of Mass Movement
[0054] Angular energetics and center of mass (CM) movements were
determined on all ten subjects while using their own klap speed
skates. The klap skate pivot point (point of foot rotation) was
positioned in the same place as the end of the hockey skate blade,
to create similar pushing mechanics (FIG. 9).
[0055] The push phase was analyzed on a modified slide board
apparatus to greatly reduce the errors associated with on-ice
kinetic and kinematic testing; exact testing methodology used by
Van Home and Stefanyshyn. The modified slide board model was set up
as follows: a 20 foot by 4 foot melamin sheet had a small block of
wood at one end where the subject performed the simulated skating
push, from this point the subject slid along the board until
friction stopped him. The slide board was bolted to a force
platform, and was surrounded by seven high-speed digital cameras,
at the location of the board where the pushes occurred. The pushing
foot was in a speed skate that had a protective low resistance
material under the blade, so that the blade and slide board was not
damaged. The contrilateral foot was clad in a running shoe covered
with a wool sock. Ten maximal pushes were executed by each
subject.
[0056] The start of the push phase was defined as the instant when
the knee angular velocity exceeded 90 deg/s, a value previously
used in the literature to identify the start of the explosive push
phase (Houdijk et al., 2002). The end of the push phase used to
simulate the conventional hockey skate push was at the instant when
the ankle reached an extension angle 30.5.degree. less than the
maximal ankle angle achieved during the actual push
(137.degree.-106.5.degree.=30.5.degree.), that was executed with a
klap speed skate. The end of the push phase used to simulate a
hockey skate push with the ankle extension conversion was at the
instant when the ankle reached an extension angle 15.degree. less
than the maximal ankle angle achieved during the actual push
(137.degree.-122.degree.=15.degree.) that was executed with a klap
speed skate.
[0057] Maximal ankle extension angle is the factor that affects the
push termination because beyond 110.degree. of ankle extension the
knee joint, even though still extending, is producing negative
power (absorbing energy) (Houdijk et al., 2002; Van Home &
Stefanyshyn). Therefore, the ankle is the only joint that can
continue to contribute and elongate the push. If ankle extension is
stopped the push will be terminated.
[0058] Kinetic data were collected with a force platform (Kistler,
Winterthur, Switzerland) sampling at 2400 Hz, which was underneath
and attached to the slide board. Kinematic data were collected
simultaneously using a multiple video camera system (Motion
Analysis Corp., Santa Rosa, Calif.) sampling at 240 Hz. Three
reflective markers (1 cm diameter) were placed on each of the boot,
the shank and the thigh for kinematic data collection (FIG. 10).
Anthropometric data collected included the subject's height and
mass and were used to determine inertial parameters from Clauser et
al (1969). Three-dimensional coordinates of each of the markers
were quantified (Expert Vision Analysis, Motion Analysis Corp.,
Santa Rosa, Calif.) and the movement within the specific
two-dimensional planes of interest were then calculated.
[0059] A two-dimensional sagittal plane analysis was performed
after smoothing both the video data (fourth-order low-pass
Butterworth filter with a cutoff frequency of 10 Hz) and the force
data (fourth-order low-pass Butterworth filter with a cutoff
frequency of 100 Hz). Resultant joint moments were determined using
inverse dynamics and then used to calculate joint power by taking
the product of the resultant joint moment and the joint angular
velocity (Winter, 1987). Energy was determined by integration of
the joint power curve. Energy absorption occurs when the resultant
joint moment is opposite in direction to the angular velocity.
Energy production occurs when the resultant joint moment is in the
same direction as the joint angular velocity. For this study,
energy productions at the ankle, knee, and hip joints were
determined. Paired t-tests (p=0.05) were used to analyze the data
for significance.
[0060] Whole body center of mass positioning and movement were
determined from the right foot, right shank, right thigh, and torso
center of mass (CM) positioning and movement. Pilot testing showed
very close agreement between this calculation and CM movement
determined from whole body tracking.
Case Studies
[0061] Two subjects (proficient hockey players) with similar foot
size and shape skated on prototypes of the ankle extension. Frontal
view digital pictures were taken during maximal ankle eversion and
inversion with the Graf Supra 703 before and after the ankle
extension conversion. The images were analyzed for maximal eversion
and inversion angles to quantify whether the ankle extension
conversion reduced ankle support. Anecdotal accounts were taken for
ankle stability qualification.
4. Results and Discussion
Angular Energetics And Center Of Mass Movement
[0062] There was a significant difference between the simulated
final CM velocity of the push with the conventional hockey skate
and the ankle extension skate (FIG. 11). The ankle extension
conversion skate had a final CM velocity of 2.83 (.+-.0.045) m/s.
The conventional hockey skate had a final CM velocity of 2.66
(.+-.0.045) m/s.
[0063] The reason for the higher final CM velocity with the ankle
extension conversion skate was that the push took 0.018 seconds
longer to execute, which allowed for more energy to be generated at
the ankle joint. The simulated push with the ankle extension
conversion skate produced significantly more energy at the ankle
(9.67 J) than the conventional hockey skate (FIG. 12). It should be
noted that the increased push time did not allow for an increase in
the knee energy generated because during the final 0.05 seconds of
the push the knee does not generate positive energy (Houdijk et
al., 2000; Van Home & Stefanyshyn).
[0064] The following example will show the effects of the 0.17 m/s
higher CM velocity, that could potentially be generated with the
ankle extension conversion skate, in an actual hockey game
scenario.
[0065] Assuming the direction of glide of the pushing skate is at
30.degree. to the longitudinal direction of the skating path
(direction of forward motion) the contribution of the push to
forward motion velocity can be easily calculated (FIG. 13). During
the acceleration phase of skating an elite hockey player takes
approximately 0.462 seconds per stride (glide phase, push phase,
and recovery phase). Therefore, if the push phase for the ankle
extension conversion skate is 0.018 seconds longer, then a player
using that skate would take approximately 0.480 seconds per stride.
Knowing the time duration of the stride and the acceleration per
stride, with certain simplifying assumptions, one could calculate
the following problem.
[0066] Problem: how much faster would Player 1 (wearing the ankle
extension conversion skate) get to a puck that is 12.27 m away than
Player 2 (wearing a traditional hockey skate)? Assuming both
players start from a stand still at the exact same position. Also,
assuming that both players are physiologically identical, and their
power per stride and stride frequency remain constant through out
the 12.27 m. The problem is answered in the diagram presented in
FIG. 14.
Case Studies
[0067] There was no change in maximal eversion and inversion angles
of the ankle joint when the frontal plane digital still pictures
were analyzed (FIG. 15). This indicates that the medial/lateral
support was not compromised with the ankle extension conversion.
The anecdotal claims support these findings.
5. Comments
[0068] The ankle extension allowed for a 15.5.degree. larger range
of ankle joint motion than the traditional hockey skate through
increased ankle extension. Through simulations, this increased
ankle extension was shown to allow a skater to generate 9.67 J more
energy at the ankle joint during the push phase. This translated
into a higher final center of mass velocity during the push phase.
In a hypothetical scenario where two players were racing for a puck
12.27 m away the player with the ankle extension skate reached the
puck 0.04 seconds sooner than the player with traditional hockey
skates. A 0.04 second time advantage at a velocity of 8.52 m/s
translates into a distance of 34 cm, more than enough distance to
gain control of the puck.
6. Description of the Ankle Extension
[0069] The ankle extension is a tendon guard with the addition of a
neoprene lower leg strap (FIGS. 1A, 1B, 2A, and 2B). The tendon
guard [1] has two cuts [2] angled distally towards the ankle axis
of rotation. The two cuts meet approximately 20 mm shy of each
other at the point of bending [3]. An elostomeric band [4], that is
inserted between the inner and outer layers of the upper and sewn
in place, crosses the cut [2] and provides recoil of the tendon
guard [1], after ankle extension. Also to ensure adequate recoil of
the tendon guard [1] a neoprene lower leg strap [5] is adhered and
stitched [6] to the tendon guard. The neoprene strap [5] fastens to
the lower leg by a hook and loop attachment [7], on the anterior
side of the leg (shin).
[0070] The advantage of the ankle extension over previous
embodiments is simplicity, effectiveness, and comfort. Very little
adjustment to the traditional manufacturing process is needed to
build the new skate into a traditional hockey skate: two cuts and
four stitch-lines need to be added. The new skate allows for
increased ankle joint extension without any detriment to support or
stability. With the addition of the neoprene lower leg strap the
wearer feels increased comfort, and the tendon guard stays within a
closer proximity to the achilles tendon throughout the range of
motion, increasing protection.
[0071] The present invention may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims
rather than by the foregoing description. All changes which come
within the meaning and range of equivalency of the claims are to be
embraced within their scope.
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