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It's a
Girl thing
Part TWO ... |
Also see:
Part ONE
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Over recent years it has become clear
that female sports performers are more susceptible to certain
injuries than their male counterparts.
In part 1 we discussed stress
fractures. In part 2 we'll consider two common knee conditions.
The first is pain at the front of the knee, which is caused
by a kneecap problem. The second is injury to the anterior
cruciate ligament (ACL).
Lets take a quick look at these two conditions before we look at why
female athletes are more susceptible to them and what measures can
be taken to prevent them.
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Philip Newton is a Chartered Physiotherapist, Director of the
Lilleshall Sports Injury Rehab Centre, and provides Physio cover to England
players at major squash events around the world. |
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Action photos by
Alex Wan |
Anterior Knee Pain
Pain at the front of the knee or ''behind the knee cap'' is a common
problem for many sports people and can be very debilitating. This
condition has a number of names including ''Patello-femoral Pain
Syndrome'' & "Runners Knee". The problem occurs between the patella
(kneecap) and the femur (thigh bone). Under normal circumstances the
kneecap presses against the lower portion of the thigh bone when the
knee is in a bent position.
During running or any step, squat or landing & jumping activity, the
kneecap moves up and down or ''tracks'' against the thigh bone and
in so doing, acts as a fulcrum, which provides a mechanical
advantage for the front thigh muscles (the quadriceps). High forces
are produced between the kneecap and thigh bone during such
activities (see figure 1).
This can amount to body weight magnified several times due to the
velocities and leverages that are in play across the knee. If the
normal tracking of the kneecap is altered, the result can be a
localisation of these large forces onto a small area of the kneecap.
This causes inflammation and pain.
So what can cause the kneecap to track abnormally? Well there are a
number of anatomical and physical factors that can do this. One that
is gender specific is the relative strength of the outer hip
muscles, which are generally weaker in females.
These muscles support the thigh and counterbalance the weight of the
whole body when weight is taken on one leg e.g. when walking &
running. It may at first thought seem strange that a problem of
muscle weakness at the hip can cause a problem at the knee.
This is how it works - the muscles concerned are known as the hip
abductors and are situated on the upper & outer portion of the
buttock (figure 2).
These muscles work every time the supporting foot comes into contact
with the
ground. They prevent the pelvis from rocking excessively sideways &
they also work to stabilise the thigh. If these hip abductor muscles
are too weak then the knee will drop too far inwards when running,
stepping & landing quickly on one foot (figure 3).
This may result in a mal tracking of the kneecap and subsequent
pain. The relative weakness of this muscle group in women may be due
to their wide pelvic dimensions. This places the muscles at a
mechanical disadvantage as compared to hip abductor muscles that
work across a relatively narrower pelvic width - as is the case in
the male pelvis.
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Anterior Cruciate
Ligament Injury
The Anterior Cruciate Ligament (ACL) is situated centrally within
the knee and is vital to the stability of the joint (see figure 4).
It is frequently injured during sport and the injuring movement can
often be quite innocuous. A common way of tearing the ACL is for the
sports person to be decelerating quickly or performing a quick
checking movement. Upon impact with the floor, the knee twists
excessively and the ACL is suddenly exposed to a massive amount of
stress, which causes it to snap. For most individuals the
consequence is a knee that is recurrently painful & swollen & gives
way during sport or even during simple everyday activities. Such
cases usually require reconstructive surgery & lengthy
rehabilitation if a return to sport is to be a possibility.
So why do proportionately more females succumb to ACL tears than
their sporting male counterparts? A couple of reasons have been
suggested. One is based on the hypothesis that males tend to have
better developed patterns of movement than females.
The suggested reasons for this are social & cultural. As an example,
boys traditionally spend more time running & jumping around than
girls, thereby establishing athletic patterns of movement at an
earlier age.
The second reason relates to the relative weakness of the hip
abductor muscles (outer buttock) that we discussed earlier. Weakness
of these muscles affects how the knee is lined up when body weight
is taken through it.
Insufficient strength and control of these hip muscles result in the
knee collapsing inwards upon sudden foot impact with the ground.
This is most likely to happen when weight is taken quickly through a
semi bent knee e.g. landing from a jump or checking quickly (see
figure 4).
Excessive inward rotation of the knee should be countered by the
action of the outer buttock muscles. If they fail to do this, then
the knee may twist so far that the ACL stretches and then ruptures. |
Injury Prevention
Helping to prevent these two types of injuries involves first
identifying the presence and magnitude of hip muscle weakness and
then following a suitable exercise programme.
There are three simple tests that can be done to check out the
strength and control of the hip abductor (outer buttock) muscles to
see if their weakness could be a pre-disposing factor to injury. Two
simply involve movements of the leg against gravity. The third is a
single leg step movement.
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Tests
The hip abductor muscles should have sufficient strength and control
to raise the weight of the leg through the full available range of
hip motion. Testing the strength of the muscles against gravity can
check this. The first two tests involve lying on to one side with
the shoulders, back and hips flat against a wall. The use of a wall
ensures that the trunk remains stable throughout the test movement
and that the leg remains in line with the trunk.
Test One
Bend the bottom leg for
stability and keep the top leg straight with the heel in contact
with the wall. Perform the test by getting an assistant to lift the
top leg to the maximum position of upward movement; making sure that
the leg is in line with the trunk (heel in contact with the wall).
The person being tested then attempts to keep the leg in this fully
elevated position as the helper removes their support. If the hip
muscles are up to full strength, the leg should remain stationary
and not drop (figure 5).
Test Two
Bend both knees and keep the
heels and backside in contact with the wall. Perform the test by
getting an assistant to lift the top leg to the maximum position of
upwards movement, making sure that the feet stay together. The
person being tested then attempts to keep the leg in this fully
elevated position as the helper removes their support. If the hip
muscles are up to full strength, the leg should not drop (figure 6).
Test Three
Stand on the leg to be
tested upon a small step (approx mid shin height). Perform the test
by lowering your body weight slowly and smoothly. Compare both legs.
The knee of the working leg should stay in line with the supporting
foot. If the outer buttock muscles (the hip abductors) are weak then
the knee will drop excessively inwards, thereby placing a twisting
force through the knee (figure 7).
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The test movements that have just been
described can be used as exercises to improve any identified
weakness of the outer buttock muscles.
To be effective, the movements should be performed slowly with
emphasis given to the weakest part of the movement. Regular practice
of these exercises will establish a basic level of strength and
control. From this base, a progression to more dynamic exercise can
be made. Examples of such exercises are squat and lunge movements.
Once good hip strength has been established & this has then been
followed up with a programme if step & squat conditioning exercises,
the final functional progression should be made.
This involves practicing jumping, landing & cutting manoeuvres,
whilst ensuring that good knee alignment is maintained.
Philip Newton |
 Also
by Philip:
Ice With Your Bath?
A shock to the System |
Also see:
Part ONE
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