The SIJ – Arguably the most important joints in
bipedal locomotion, does yours function?
Saul Yudelowitz BSc (Hons)
Disassociation is the
action of the pelvis and the trunk moving through the transvers plain in
opposite directions, simultaneously.
While this sounds simple
the vast majority of the adult population in the developed world cant do this
basic movement pattern.
In terms of postural ontogenesis, we develop the
ability to disassociation at about 6months old when we first roll into the
prone position from the supine position. Once in this position we have two main
stimuli’s, visual and tactile.
To begin moving we start by moving the pelvis
through the transvers plain, as we continue to develop and get up onto our feet
the development of disassociation is almost completed when we have learnt
pelvic floor control, leading to control of urination and defecation. As a
young child we continue to develop and learn motor control so that we can move
with better control, this is where we learn to protect the joints.
two main problems that contribute to dysfunction of disassociation. First, most
parents rush the development of the reptilian phase when their child is
crawling on their belly. This typically stems from parents competing with
friends and family as to when their child can begin to walk. The second part of
the problem is that as soon as we are school going age we sit and sit and sit.
The sitting problem continues for the majority of us through out our life. We
sit during out journey to work or school, we sit at work or school, on the way
home. We sit when we are home and then go to sleep and repeat the entire
process. What some people reading this will think, that standing more often is the
key however this is an over simplistic approach to correcting this issue.
important key is to have the ability to dissociate while walking. Once this can
be regained, running, hopping, skipping, jumping or any movement pattern that
you care to do is covered. It will also allow for the core to function so if
any therapist does not include dissociation rehabilitation in addressing the
core your core will never be functional. The feet have a direct neural and
facial connection to the feet and this has a significant influence on core
function. Disassociation will allow the feet to work as they were designed to
The SIJ is a complicated joint that consists basically of a superior
and inferior portion. Movement, which is debated still to this day, does occur.
This movement is small, in the range of 2 – 4 degrees. What needs to be
understood from this is that if you loose between 1 – 2 degrees of the range of
movement here you loose 50% of the joints range of movement. 1 – 2 degrees is not much so we want to keep
the SIJ mobile as this is a significant amount. Anthropologists when asked to
age the skeleton look at the two SIJ joints and can place a rather accurate age
of the skeleton. This joint is consistently adapting to the loads placed on it.
The Bicep Femoris make up the lateral aspect of the hamstring compartment. Its
tendon continues upward from the ishicial tuberosity to blend in with the
sacrotuberous ligament, as well as branching medially to attach to the lateral
aspect of the coccyx and continuing upward to blend with the long posterior sacroiliac
ligament. This arrangement has a significant effect on the SIJ and since the foot
affects the Bicep Femoris it is considered a long lever of the SIJ.
imbalance between the medial and lateral compartment of the hamstrings will
cause a malalignment of the hip. It is very common to find the medial
compartment stronger that the lateral compartment of the hamstrings. This leads
to an internally rotated hip, an eccentrically loaded Piriformis, a muscle that
commonly leads to sciatica and of course SIJ malalignment. In this example it
is common to find the SIJ stuck or the range of movement significantly reduced.
It becomes very clear that the body is a tensegrity structure from the above
example. Some therapists will manipulate the SIJ with out correcting muscle
imbalances, this is why the patient will need to keep returning for treatment
and since the body can be looked at as a tensegrity structure, symptoms can
occur in many different places and not the initial site.
Having the ability to
disassociate is extremely important and if taught to children at school the
incidence of lower back pain would decrease. Disassociation can be seen in all
sports. Athletes have a better ability to do this than the average person and
so movement for them is more controlled and powerful. If you can’t
disassociate, your entire abdominals, which consist of four different muscles are
dysfunctional. Ask any 100m professional sprinter how hard their abdominals
work when sprinting. Your typical abdominal exercises seen in the gym like sit
ups, leg raises, crunches with twists and most of the others are at best
extremely poor. Watch someone standing on a core board, if they can dissociate
then they will tell you their abdominals are working harder than any exercise
they have ever done.
Learn how to dissociate and you will engage the core,
abdominals, gluteal muscles and feet, the source of power in all movements. Just
going for a run and not running correctly will only wear out your joints
quicker! Cherish what you have as you will miss it when its gone.
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