Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE~ INVENTION
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1. Field of the Invention
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This invention relates generally -to the field of
muscle development, exercise and rehabilitation and more part-
icularly, to a new rotator muscle exexcise apparatus.
2. Description of-the Prior Art
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In designing strength or exercise training equipment,
consideration must be made of several different factors. These
factors include muscle contractions, their types and modes of
operation , the specific muscle which the person wishes to
develop, the mode of its operation and its particular s-tructure.
This latter consideration is commonly referred to as specificity
of training or specific muscle isolation.
The present invention relates to the development of
' ~ rotator muscles wi~h particular reference to resistance exercise~
Exercise for the muscles responsible for rotational movement
~of the leg is advocated for many reasons, including, inter a~iQr
:
to increase strength, to maintain exis~ing strength, to prevent
injur~, to rehabilitate when injury occurs, and to improve or
maintain flexibility. The importance of strength training to
conditloning programmes for athletic participation is sometimes
overlooked in favour of cardiorespiratory endurance development,
but both should be considered in conditioning programmes.
While the importance of strength to the calibre of
athletic performance will vary depending upon the sport, a
minimum strength is required for each sport. Strength is re-
quired for good performanca in each sport, for endurance, ac-
celeration and motor control to co-ordinate the activation of
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muscles throughout the body to achieve optimal results in
producin~ the desired movement.
Physiologists believe that training of athletes should
be as specific as possible to the actual conditions of the sport
in which the athlete is involved.
It appears that the central nervous s~stem undergoes
adaptions during strength training that permit an individual to
more fully use the available muscle capacity. The basic muscle
capacity itself, may also increase in the forrn of hypertrophy
1~ and structural changes. The most efficient mode of training
would appear to be one in which the muscles are activated in
as similar a manner as possible to that of the actual athletic
performance, so that the central nervous system uses specific,
consistent neural pathways.
A strength-training unit, designed to specifically -
~~exercise the muscles involved in leg rotation, is therefore,
more logical tha~ using devices which exercise the same muscles
bu~ in other functions. That is, the muscles involved in medial
rotational (inward turning) of the tibia or the femur at the
flexed knee joint are the medial hamstring muscles: sartorius,
gracilis, semimembranosus and semitendinosus. The biceps
femoris muscle acts alone to laterall~ rotate the knee. It is
noted that the popliteus muscle, which lies across the posterior
aspect of the knee, unlocks the knee joint from terminal lateral
rotation o~ the tibia. While these hamstring muscles are also
active during flexion of the knee and can be trained with this
movement, if increasing knee rotational strength is the goal of
the exercise pro~ram, then knee rotation exercises are more
appropriate. A similar statement can be made for the hip
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rotator muscles, which also are actiYe in two or more movements
of the hip joint.
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1 In summary, it is concluded that increased strength
for the movements of hip and knee rotation can contribute to
improved performance in events ~here powerful forces are
required to be developed by the involved muscles. Optimal
training for increased strength, or strength maintenance would
appear to take the form o~ the actual rotation movement, although
the involved muscles may receive some benefit from other types
of joint movement. The knee rotation strength of the hamstring
muscles is not predictable from their flexion strength, a
finding which has obvious important implications for strength
testing procedures~ It thus appears that knee rotation strength
should be tested separately from knee flexion strength.
After a period of strenuous training for increased
strength has resulted in the attainment of desired strength
levels, a less extensive program to simply maintain those levels
may be instituted. That is, the muscles are no longer provided
wlth the constant "overload" stimulus that is necessary for
~; strength improvement. Rather, a program of reduced intensity may
be utilized to prevent the strength losses which would occur if
~ training activity was completely stopped, that is, in the
case of training programs for athletic competition for example,
during the off-season. Ideally, the athlete can take his strength-
training equipment with him, when travelling during the competi-
tive season, and accurate records of streng~h levels are kept
year-round.
It is apparent that the integrity of a joint depends
on several structures, namely, the bony structure of the joint,
the supporting ligaments and the muscles surrounding it. While
the bony struc~ure of a joint seems fixed, at least after
maturation of the skeletal system, it has been observed that the
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1 ligaments and muscles of a joint can be stengthened through
training programs, thereby adding stability to the joint
~ n the case of preventing knee joint injuries, the
contribution of the rotator muscles has received little attention
until recently. Commonly, the knee was discussed in terms of its
flexion and extension function, with considerable importance
being placed on having balanced quadriceps (extensors) and ham-
strings (flexors) strength. It appears that rotational knee
exercises should also be part of an athlete's conditioning
program, because as discussed hereinafter with respect to re-
habilitation of joint injuries t the knee is often subject to
- rotational torques that sometimes cause severe internal derange-
ment.
There can be no question however, that preventive con-
ditioning programs are worth the time and effort, when the
considerable money and sport participation time that are lost
at all levels of competition due to injuries are considered.
Prevention of sport injuries should be a multi-faceted endeavour,
: including attention to e~uipment, playing conditions and rules. But the importance of physical conditioning should not be over-
look.ed. The recreational athlete may be particularly prone toinjuries stemming from poor conditioning for sport participation.
It has been observed that injuries to the knee constituted
45.5% of all iniuries seen in a sports medicine clinic that dealt-
with primarily recreational athletes, a figure whichstresses the
vulnerability of the knee in this population.
Knee joint injuries are considered to be the most
common form of joint injury suffered by athletes, particularly
by those who engage in contact sports. One of the major mechan-
isms of injury is that oE a rotational torque being applied to
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t the femur, while the foot and lower leg are in a state of
fixation and the knee joint partially flexed. This rotational
torque, which can be the result of a force applied to the
lateral side of the knee (e.g. a football tackle), can produce
a very serious derangement of the ~nee joint ]cnown as the
"unhappy triad": where tearing of
1. the medial collarteral ligament
2. medial meniscus and
3. anterior cruciate ligament occurs. Rotar~ instability
appears to be a consequence of such knee ligament injuries.
A commonly used approach to correct this instability
is the surgical procedure known as the pes anserinus transplant~
in which the medial hamstrin~s effectiveness as a medial knee
rotator is surgically increased, via a tendon transplant, thereby
providing muscular stability to the knee. As a result of the
surgery and inactivity, however t muscle atrophy occurs which must
.
be reversed before these muscles can fully contribute in their
new stabilizer role. Progressive resistance exercise is advocat-
ed for strengthening purposes and specific training devices for
the knee rotators appear to be warranted. Further it seems
appropriate that in any rehabilitation of a previously inactive
knee, the rotator muscles should receive training, as well as
the extensor and flexors, but this is not always done. The
same conclusion can be applied to the rehabilitation of hip
function.
The devices of the prior art have attempted to
consider the foregoing principles but are not in widespread
use. Some of the devices use weights for resistance such as
that reported by Robertson et al, Medicine and Science in Sports,
Vol. 6, No. 4, pp. 277-282 (197~). This device was developed
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1 to obtain information concerning the use of active resistive
exercise in rotation of the leg and its effect on the stabilit~
of the knee, and is ~uite complicated in structure. Other
devices such as the Lumex Isokinetic System and others, do not
specifically act on the rotator muscles.
This type of e~uipment on the market today, in addition
to the previously mentioned drawbacks, is extremely cumbersome
and expensive. As a result, it is found only at health clubs,
rehabilitation centres, and the like with the result that they
1~ do not have widespread use by athletes who require a light-
weight, inexpensive and portable apparatus which is suitable
for home use and also use at training facilities.
SUMMARY OF_ TI~E INVENTION
Accordingly, it is an object of the present invention
to at least partially overcome these disadvantages by providing
a novel rotator muscle exercise apparatus which will produce
muscle contractions of varying intensities through a full range
of motion.
It is a further object of this invention to provide
a novel rotator muscle exercise apparatus which is simple in
design and which may be manufactured and sold for home use.
It is a yet further object of this invention to
provide a light-weight and portable rotator muscle exercise
apparatus.
A further object of the present invention is to
provide a rotator muscle exercise apparatus which uses no
auxiliary fluid supply source and is completely self-contained
and easy to operate.
A further object of this invention is to provide a
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1 novel rotator muscle exercise apparatus which allows for
specific muscle isolation and specificity of training for the
rotator muscles.
A further ob~ect of the present invention is to provide
a novel rotator muscle exercise apparatus which allows an athlete
to increase the strength of his rotator muscle, maintain the
existing strength, prevent injury and to rehabilitate selected
injured rotator muscles.
To this end, in one of its aspects, the invention
provides a rotator muscle exercise apparatus which comprises a
pair of rotatable foot rests, each foot rest operably connected
to a separate air cylinder whereby the pressure of the air
within said cylinder is controlled by the rotation of said
foot rests.
In another of its aspects~ the invention further pro-
! vides a rotator muscle exercise apparatus which comprises a
(i~ a pair of rotatable foot rests.
(ii) a pair of air cylinders containedwithin a housing, each
eylinder in~luding a toothed piston rod and a piston seal
attached to one end thereof, said seal adapted to control the
pressure of the air in said cylinder,
(iii) at least one air valve adapted to regulate the pressureof the air within said cylinder,
(iv) eontrol means adapted to control the operation of
said at least one air valve,
(v) a pair of indicator means, each indicator means com-
munieating with one air eylinder and adapted to indicate the air
pr~ssure within said cylinder.
(vi) support means adapted to suppor-t and balanee the user
of the apparatus, and
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1 (vii) two drive means adapted to drive the piston rod in-
wardly or outwardly of the c~linder in response to rotational
movement of said foot rests, whereoE the amount of air pressure
within each cylinder is increased or decreased in response to
the rotational movement of the foot rest.
Further objects and advantages of the invention will
appear from the following description taken together with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is an end elevational view of the rotator
muscle exercise apparatus o~ the present invention.
FIGURE 2 is a top view of the rotator muscle exercise
apparatus of the present invention.
FIGURE 3 is an exploded sectional view along line
III-III of figure 2.
! FIGURE ~ is a secti~nal view along line IV-IV of
figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
2~ Referring first to figure 1 and 2, there are shown an
end elevational view and a top view, respectively, of the rotator
muscle exercise apparatus of the present invention.
The apparatus comprises a base 32 which is a thin
plate which extends the length of the apparatus and has an
upturned forwaxd portion 31 as shown in figure 3. A Eorward
housing 16 is mounted on the Eorward part of the base 32 and in-
includes a front part 19 at its Eorward end which is secured
to the top edge of the upturned forward portion 31 of base 32
as shown in figure 3. A rear housing 10 is mounted on the
rear oE the base 32 and abuts the rear end of the housing 16.
A pair of eao~ rests
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1 12, each of which is mounted on a separate shaft sleeve 14, are
located on the top surEace of rear housing 10. A handle 20 is
mounted on a lever 22 which moves in 510t 24 which is cut cent-
rally in the forward part 19 of the housing 16. A pair of gauges
26 are located on a bracket 42 which is secured to the upturned -
front part 31 of base 32. A support stand 28 with support base
30 on the top thereof is located at the forward end of the
device.
Referring now to figure 3, there is shown an exploded
sectional view along line III-III of figure 2. It must be
remembered that only one side of the apparatus is shown and will
be described although the structure of the apparatus is
substantially duplicated on the opposite side, the purpose of
: . which will be explained hereinafter.
Inside housing 16 there is located a pair of air
cylinders li (only one is shown) which lie parallel along the
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length and within housing 16. Each air cylinder 17 is con-
~: talned within housing 16 and includes a piston 34 which com-
~: prises a piston rod 36 and a seal 38. The piston 34 is movablealong the horizontal axis of each cylinder 17~ -
A hose 40 is provided at the forward end of each
cylinder 17 and communicates with said cylinder 17 and a gauge
26 is mounted on bracket 42 which is in turn secured to
the upturned forward portion of the base 32. The support stand
28 is mounted on the upturned forward end 31 oE the base 32 with
support bar 30 at the top oE the stand 28.
An air valve 44 is provided at the forward ènd of each
cylinder 17 and communicates therewith via the threaded valve
- connection 46 and is controlled by a single lever 22 which
terminates in handle 20. A slot 24 is provided on the top of
the housing 16 for movement of the lever 22.
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A stand 64 located within rear housiny 10 is secured
to the base 32 by bolts 48 or any other suitable means.
The piston rod 36 is formed as a rack member with
teeth 37 on the peripheral surface thereof and fits within rack
guide 50 which is mounted in stand 64. In the assembled condition,
the teeth 37 of the piston rod 36 engage the teeth o~ gear 52
which is fitted on a vertical shaft 54, the bottom end of which
is seated in a thrust bearing 56 which is supported by mount 58.
The vertical shaft 54 is supported in the vertical position by
means of second bearing 60 mounted in brace 62. The brace 62
is mounted on the top surEace of the support 6~. A foot rest
12 is mounted on the top of each vertical shaft 5~ by shaft
sleeve 14.
Referring now to figure 4, there is shown a sectional
view along line IV~IV of figure 1, which shows the structure of
figure 3 in the assembled condition. As seen in figure 4, as gear
52 is rotated in any direction, this will drive the piston
rod 36 forwardly or rearwardly.
The operation of the novel apparatus will now be
explained. The user of the apparatus, either in the standing
or the sitting position, places his feet in the foot rests 12
and performs either of two essential movements b~ rotating his
feet.
The first movement is achieved by rotating both feet
in a clock-wise direction then rotating the feet in a counter-
clock-wise direction in unison. Basically, this movement involves
the use of the hip joint and trunk muscles of the obliques and
lower back if the user performs the exercise in an upright or
standing position. When the exercise is performed in the seated
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position, the primary areas affected are the ankle and the knee
joint>
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l The second basic movement lnvolves the use of the
ankle, knee and hip joint when performed in a s-tanding posi-tion.
This is accomplished by rotating the ~eet toward each o-ther
and away from each other. When done in a seated position, the
primary areas affected are the ankle and the knee joint.
As can be seen from the drawings, as the foot rest
12 is rotated, this causes gear 52 to drive the piston rod 36 in
a forward or a rearward direction. This in turn changes the
volume of the area in front of the piston seal and the front
wall of the air cylinder 17 thus creating either increased
pressure or a partial vacuum therein. By manipulating the
handle 20 which controls the air valve 44, the amount of air
pressure in that cavity may be adjusted thereby allowing the
operator to adjust the resistance or tension of the exercise
to suit his own needs. The level of the air pressure is easily
read by the gauges 26 which are attached to the respective cylind-
ers. Support bar 30 is used to allow the user to maintain his
; balance during the exercise.
The apparatus is very beneficial in developing,
~20 strengthening and rehabilitating rotator muscles. The apparatus
allows for exercise of various rotator muscles which are
essential to development, some of which are now outlined.
The apparatus allows for both inward rotation and
outward rotation of the hip joint, thus directly acting on the
gluteus medius, gluteus minimus, tensor fasciae latae, adductor
longus, adductor brevis, adductor magnus, and iliopsoas major
; muscles ~inward rotation) and the gluteus maximus, piriformis,
obturator externus, obturator internus, the gemelli (superior and
inferior), quadratus femoris, sartorius and adductor magnus
muscles (outward rota-tion).
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1 The appaxat~ls also allows for proper exercise of the
abdomen since the rectus abdominis, the external and internal
oblique muscles all work during rotation.
Although the types of movement allowed by the vertebrae
vary considerably, rotation occurs most ~reely in the cervical
and lumbar regions and to a limited degree in the docsulumbar
region. It has been long recognized that all conditioning
programmes should include exercise involving the spine or verte-
bral column to help prevent back injuries. Such exercises in-
l cludes correction, amelioration or compensation of functional
postural deviations, maintenance or increase of the trunk-and
general body flexibility and increase of trunk and general body
strength.
All basic conditioning should include an emphasis on
trunk flexibility and the present apparatus allows for maximum
range of motion in trunk rotation in lateral flexion. The
apparatus develops the extensors and abdominal strength which aids
in proper postural alignment. The appaxatus also allows for
restoration of normal flexibility, strength improvement and post-
uràl correction for rehabiliation after injury.
The apparatus also allows for good exercise of the
knees. Outward rotation o the knee is controlled by the biceps
~ ~ femoris, and inward rotation by the popliteus, the semi-tendiosus
;~ the semi-membranosus, the sartorius and the gracilis, all of
which are properly exercised with this apparatus.
It is also important that with the current popularity
of the pes anserinus transplant surgery for rotary instability
of the knee, special exercise considerations must be given.
The pes anserinus is the aponeurosis of the internal hamstring
muscles and when surgically transplanted, is brought forward to
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1 the front o~ the tibi2. In addition to a -therapeutic exercise
programme to promote flexibility and prOCJreSSiVe resistive exer-
cises, the present apparatus allows the athlete to perform
in-ternal tibialrotation with progressively increased resistance.
The present apparatus avoids the use of complex
and expensive devices of the prior art and needs no electrical
input. It is a relatively simple and efficient apparatus which
can be manufactured at a low cost and which can easily be made
portable.
Several other advantages of the present apparatus
include the following. The present apparatus is based on the
air pressure within the cylinder and thus, provides an advantage
over the devices which utilize oil pressure to create resistance
of movement. No recharging is necessary and no lea~age of
messy oil can occur.
The presen~ apparatus allows complete freedom OL
movement and can be used in the standing, the sitting or the
kneeling position. Rotation can also be made in either direction.
The present apparatus is completely self-contained
and needs little or no maintenance. It allows the user to adjust
to his own needs, the amount of resistance to exercise thus
allowing complete specificity of trainin~. It provides for
concentric contractions and can be altered to provide this
type of contraction easily and quickly by the user.
Various modifications of the apparatus may be made
within the spirit and scope of the present invention. These
modifications may be made to reduce the amount o~ material
required to produce the apparatus to reduce its cost and weight.
Some of these modifications will now be described.
Base 32 may be replaced with a pair of rails which
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1 extend rearwardly from the upturned forward portion 31. In
this embodiment, housing 16 rests on the rails and the stand
64 is secured directly to the rails by any well known means
such as bolts 48. This would reduce the weight of the
apparatus.
In another embodiment, the yauges 26 may be located
on the top of housing 16 and in direct communication with each
air cylinder 17. While gauges 26 are not essential to the
invention, they do aid the user in determining the relative air
pressure within the cylinder. The location of the gauges is not
critical provided that they are large enough for the user to
read easily from the operating position.
In a still further variation of the apparatus, the
number of valves 44 may be varied and as a result, the number of;
levers 22 may also be varied. For example, a single valve 44
with a single lever 22 may serve to vary the amount of air present
in both cylinders 17 or alternatively, there may be present two
valves, each of which communicates separately with one cylinder
17 and one lever or two levers. In the embodiment utilizing
two valves and a single lever, the lever opens and closes the two
valves simultaneously. If the two levers are used, each lever
could operate a ~ingle valve and the amount of air in each cylinder
would be independently controlled.
Although the disclosure describas and illustrates a
preferred emhodiment of the invention, it is to be understood
-the invention is not restricted to this particular embodiment.
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