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Thorny
i
noticed two thinks at lunch today. even with injuries peoples dominance can
show up. i saw a guy with a really messed up left knee. his right leg was
healthy. but he still took a longer step on his left leg. what i couldn't
figure out was whether he shortened his right stride out of force of habit or
comfort for that stride, or if dominance.
is so ingrained we even carry it when the dominant leg is injured
(perhaps at the expense of healing quickly/?)
I also noticed people keep their dominance while shuffling. ya gotta look hard
but they do.
Del
How are we to establish limb dominance?
Coop05
I believe that dominance can be seen in the length of the strides.
Your dominant foot is somewhat stronger and will carry you farther, while
your non-dominant side will not want to hold you up as long making the stride
shorter. so the side with the farthest stride is your non-dominant foot, and the
leg with the smaller stride is your dominant.
we
are born with it, like right handed or left handed,
though it's not necessarily the same in our legs as our hands. you
could be right handed but left dominant walking. but with serious coaching and
practice you can fake dominance which will probably be discernible to a
experienced tracker.
to observe it in others, see which step is the longest by either measuring or
timing them. i am right dominant. therefore i push off longer or carry my left
leg further than i do my right. so right dominant carries left leg further
making larger step and left leg doesn't carry right leg as far taking smaller
step. so if yer right dominant you will circle to the right and left dominant
people circle to the left when lost and wandering.
Del
Dominant
limb being then ... the stronger leg?
As in left or right handedness? Is step length the only way to determine
this within yourself?
On others? Is there any gait pathologies that would alter this
dominance (or step length) and confuse interpretation (in the field)?
Can a person be ambidextrous with his/her limb dominance? A neutral/equal
balanced gait?
haven't
observed any ambidexterity in legs yet but it might be possible.
i've seen it close to that. i think limb pathology would lead to whatever limb is stronger being dominanat but even that guy
limping on his knee retained the
dominance of his bad leg so you'd prolly have to abserve a TON o people to find out fer sure.
stride length is pretty much the determining factor but ya need a lotta
tracks cuz terrain and other factors may affect it. i've seen people
carrying pretty heavy shit on their dom. leg and it still carries the
long stride, even with all that weight on it. it's like an irresistible
genetic predisposition.
Dominant
limb is probably the stronger leg but it is the leg you are most comfortable
balancing on.
>
As in left or right handedness? < Yes,
as long as you realize that dominance is not the same (right-handed person may
be left dominant).
>
Is step length the only way to determine this within yourself?
On others? <
It is also a "choice" thing. Given 2 equally good routes, a
person will normally go in the dominant direction. Tracker students often take
the non dominant path just to stay out of a rut. Another way to tell is to
stand on the 50 yard line of a football field on a cloudy day. Close your eyes
and walk normally to the end zone. You will end up "out of bounds"
by the 20 yard line on the dominant side. This is from one of Tom's books, but
I did try it myself and it was true for me. This is also the reason a lost
person almost always walks in a large circle as he tries to find his way.
This is a big issue for me as a tracker on a
search and rescue team, statements that use the word ‘ALWAYS’ have caused
many problems during searches.
> Are there any gait pathologies that would alter this
dominance (or step length) and confuse interpretation (in
the field)? <
If
you carry some weight in your hand, it will affect your stride. So you could
weigh down your non dominant side to where you walk straight.
At
this point in the discussion Fred has made reference to an exercise that Tom
Brown Jr expounds to determine ones limb dominance.
One
is to stand in the end zone of a football field, blindfolded, and pointed
towards the other end zone. It is claimed that if you exit the football field
to the right sideline then your limb dominance is ‘right’ ... and visa
versa. If you luck out and go straight then you have no limb dominance?
I
think Tom says you will reach the sidelines by the 5 yard line.
I am so right dominant that I barely made it past the twenty.
But
is this really dominance of one side over the other?
Think about this ... My left foot
steps out 20" and then I follow with a right step of 25" completing
the gait cycle. Beginning the next gait cycle with a Left 20 and then a right
25 ... and so on.
|_L 20_|
|_L 20_|
|_L 20_|
|_L 20_|
|__R 25 __|
|__R 25 __|
|__R 25 __|
|__R 25 __|
At the end of each gait cycle you have traveled forward in a direction that is
determined by some different navigational activity. Navigation or direction of
travel is not determined by step length. What is this "magic" that
is changing our direction when we
walk blindfolded? Is it really a limb dominance? Perhaps an inner ear balance
thing? A center of gravity arm swing thing? A hip/spine flexion variation?
I thought I had read somewhere that the army (Korean war era) studied this in
great detail and found no statistical correlation to ethnicity, training, leg
dominance, or field practice in regards to a lost person (blind folded on a
cloudy day) circling left, right, or not at all.
KLS
Your
hips could be out of place. If this is the case, then one leg is a little
longer than the other; thus one stride being longer than the other.
At
this point in time I shared George Gorton’s statement about step length and
gait analysis.
*******************************
Since a "step" is defined
as the offset position BETWEEN limbs, it is not the step, but the stride that
must be equal to walk in a straight line.
There are many mechanisms that can affect the ability of a leg to achieve a
"normal" step length. Perry (Gait Analysis, 1992) describes the role
of the ankle "rockers" in progression. In a hemiplegic gait, for
example, a typical subject may have a plantar flexion contracture on the
affected side on clinical examination. If the contracture is flexible, adequate
dorsiflexion may still be achieved in stance and the step length of the
unaffected side will not be limited. If it is not a flexible contracture,
however, at least two options are available. If the patient remains in equinus
without a midfoot break, the progression of the tibia over the foot in stance
will be restricted and this will shorten the step length on the unaffected limb.
If a midfoot break occurs, or hyperextension of the knee joint occurs as the
result of an external extensor moment from the equinus in stance, then adequate
progression may occur to maintain a near normal step length.
In the same type of subject, we may find a knee flexion
contracture. This would limit step length by limiting the forward reach
of the swing limb.
Working
back from this, if there is a hemiplegic gait with a short step length on the
good side, we should look to mechanisms affecting forward progression and weight
transfer on no the affected limb (eg - limited hip extension or limited
dorsiflexion in stance). (Although there may still be compensatory tightness on
the unaffected side.) If the step length is short on the affected side, then we
should look to mechanisms of reach (eg - incomplete extension of the knee or
inadequate hip flexion).
Part of the difficulty here is in reliably identifying "affected" and
"unaffected". Even in a hemiplegic population, the designation may not
be clear cut and there may be compensations that cause the
"unaffected" limb not to mimic normal joint motions. If we move to a
CP diplegic population with this assessment, everything falls apart because both
limbs are affected and we can not separate limitations of reach from limitations
of forward progression and weight transfer.
What we are left with is that step lengths are indicators of an ability to
compensate for limitations of propulsion and advancement. Inadequate strength
may limit a person with a polio residual from flexing the hip adequately, but
with a caliper type gait, they may still achieve a near normal step length
bilaterally using pelvic and trunk rotation. The identification of this gait
does not come from looking at the step lengths themselves, but by understanding
that the lack of hip flexion and knee extension require a transverse plane
compensation to maintain adequate step length for progression.
In a person who has asymmetric step lengths, we know that there is a kinematic
deviation that exists that is not compensated for. We can not tell however, from
this information alone, what the deviation is, or what side to look for it.
Therefore, at least in my own mind, asymmetric, or shortened step lengths are
indicators of the presence of a problem, but not diagnostic in their own right.
George
E. Gorton, III
Director, Gait Analysis Laboratory
Shriners Hospitals for Children
Springfield, Massachusetts 01104
that
guy's not a tracker. he's a "gait analyst". no wonder it seems like
dominance needs to be clarified. but it
doesn't. dominance means one stride is longer than the other. that's
it. nuthin to clarify. you can tell which stride is longer by watchin'
somebody walk or lookin' at their tracks. it's very simple.
the way you stay on course with one stride being longer than the other
is by making continuous subtle compensations for direction. look at the soles
o' yer shoes. they don't wear the same way. cuz they hit and push off differently. that's do to compensations you make on
visual information. put a blindfold
on and you no longer have that info and you
walk to the dominant side. it's very simple.
one more thing about dominance that is very simple: whichever side is dominant,
you tend to choose that direction given an equal (or almost
equal) choice of directions (to navigate around a tree or prickerbush or
piece of furniture, for example). so you can thow people off by
choosing the opposite direction of yer dominance.
Personally,
I have seen inconsistency on limb dominance
over and over in my studies and I have been looking at human tracks for
14 years. I have tested people (using the football field technique) and have
logged conflicting results. Testing must be done without their knowledge of why
they are being blindfolded. Once you tell them any information about the purpose
of the test or the results of the previous pass, YOU have altered the test by
implanting a concept within their minds that will alter their "blind"
navigation. So testing yourselves is nonsensical in that you will be thinking
about left or right dominance during the course of your walk.
I
seem to recall that in one medical class we were told that the
dominant leg is stronger, thus the punch step (short) and swing step
(long). I have tested many people and found that most of the time
they will go out of bounds by about the 50 yd line. Some people, women
especially, seem to be better at walking a straight line. I seem to
recall reading somewhere that with nothing to keep track of direction a
"normal" man will circle in a one mile radius.
The ground here is not all flat, but when the rest of the club gets back I will take them down to Pope Valley and test them. I
think that you will find that
people can be trained to be right or left dominant.
My sister and mother are both right handed/right dominant
but they both throw, catch and bat left handed. Easy to figure out why,
the only other mit around when I was learning baseball was a
lefthanders mit. They had no
choice but to learn lefty. I am,
by testing, right handed/left dominant. I only know a few other
people with an opposite combination like that. Specifically we find it
easier to write and do delicate tasks with our dominant hand while
circling and making choices in the opposite direction.
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