Proprioception
What is it and why you need to know about it
Robert H. Sheinberg, DPM
How often do you talk to a person who sustained an injury such
as an ankle sprain and they tell you "All of my swelling, bruising
and pain is gone, but my ankle still feels weak! I'm afraid to walk
over uneven surfaces because I'll sprain my ankle again. I feel
fine walking on sidewalks or paved areas, but I even feel unstable
walking in my back yard." Also, we've all seen/known those
people who just seem to sprain their ankles frequently or have a
tendency to be clumsy and trip often.
Quite often, these people do not have muscle weakness in the ability
to push their foot down, pull their foot up, or turn the foot in
or out. Watching these people walk on a smooth or paved surface,
it appears as though they have no problem. But let them walk across
a lawn or a sidewalk or parking lot that is old, uneven and may
have cracks in there and you might think that person has just aged
50 years or that an infant could traverse the area better.
The key to this person's problem is poor proprioception. Proprioception
is a part of our nervous system that gives us the ability to maintain
balance and an upright posture, no matter what surface we walk on,
what position our body is in, or whether we are even in contact
with the ground or not.
There are small sensory fibers located within ligaments that surround
a joint, within the capsule that encloses a joint to protect it and seal
the joint fluid inside of it, as well as within tendons that connect
muscle to bone, particularly in the area where the tendon crosses
the joint. Proprioception acts very similar to a reflex arc and
allows our mind to visualize what position a joint or body part
is in, despite the fact that we may not even be looking at that
part of our body every given moment. An example of this sensory
mechanism is to imagine yourself standing up with your eyes closed.
You hold out your hand. Someone walks up to you, lightly grasps
your index finger on each side and moves your finger down. Without
even looking at the finger, you know that your finger is in a down
position.
How this relates to functional stability in a joint is as follows:
these receptors, if stretched too far in one direction (as when
someone's ankle is starting to twist inward if they step into a
divot in the ground) send a message to the brain, telling it, "the
ankle joint is moving too far inward". Instantaneously, the brain
sends a message to the muscles located on the outside edge of the
leg that have tendons that cross the ankle joint and attach on the
outside edge of the foot. These muscles then contract, causing the
excessive inward twisting to stop and the ankle joint to be brought
back straight.
This system, however, is not perfect. Often if the force at the
joint being injured is too great or too quick for the proprioceptive
system to act and recover, a sprain (or even worse, a dislocation
or fracture) occurs. These injuries will have dual effects on proprioception.
Depending on the level of injury, differing degrees of damage to
the proprioceptive fibers occur. Also, there is usually some degree
of immobilization to the joint, no matter if conservative or surgical
intervention is necessary. This immobilization tends to dull
the proprioceptive response secondary to lack of feedback, no matter
how complete the recovery is to the joint capsule, ligaments, or
tendons. An example of this is comparing the athletic ability between
an athlete who practices year round and an athlete who only practices/participates
during the active season- the year-round participant will demonstrate
greater skill earlier in the active season, while it may take an
entire season for the seasonal athlete to hone his skills.
Henceforth, during the recovery process it is very important to
incorporate not only strengthening and stretching exercises for
muscles in the affected body part, but also specialized exercises
to stimulate recovery of this proprioceptive feedback so that not
only are the muscles strengthened in a gross manner, but they also
have been trained to respond quickly to any movements beyond normal
range of joints that they cross. There are movements and exercises
that can be incorporated early in the rehabilitation program, even
before weight bearing is allowed. As a patient continues to improve
and begins to ambulate again, more exercises are incorporated to
further perpetuate the proprioceptive recovery.
A Biomechanical Ankle Platform System(BAPS) helps a person to regain
and sharpen proprioception.
Also of paramount importance is identifying any underlying biomechanical
abnormalities that may be present which could, at a low level, contribute
to reinjury of the body part. Examples of this are excessively high
arch or low arch feet, knock-knees or bowleggedness and any muscular
tightness of various muscle groups. In people with these anatomic/mechanical
entities, the proprioceptors have been put under abnormal stretch
from the time the person has been walking and unfortunately, the
feedback system has been either dulled or has adapted itself as
"normal" for that person's biomechanical abnormality.
Often a custom-molded in-shoe orthotic will be of great benefit
to help hold the foot in the most structurally and functionally
stable position in order to help the foot and ankle. Also, by keeping
stress and strain off of the proprioceptive fibers, they can function
at a normal and appropriate response level. Minimizing barefoot
walking or walking in shoes that are unstable or provide little
support(high heels with a narrow heel or top sider boat shoes) will
also help.
By providing a comprehensive care plan which must include proper
proprioceptive rehabilitation and minimizing any abnormal biomechanical
function, we can help to make your recovery from a lower extremity
joint injury a smooth one.
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