BIOMECHANICS FEEDBACK OF DAY2 PRACTICAL AT STANMORE

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BIOMECHANICSFEEDBACK OF DAY2 PRACTICALAT
STANMORE

• Don Grieve

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LINE OF WEIGHT AND THE BALANCE BOARD.UNDERSTAND
THE PRINCIPLES INVOLVED(and possibly find out
how strain gauges and force transducers work)
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Why was the voltage noted when the board was
empty?
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Segment lengths are roughly proportional to
stature
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Anatomical landmarks on left, balance board
results on right
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When the data are plotted alongside a lateral
X-ray of the foot, the functional limits of the
footbase (the bony calcaneum and the metatarsal
heads) become apparent, rather convincingly in
the next slide.
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Taking things further, the next slide indicates
the trabecular arrangements in the foot bones.
What determines these arrangements? The crude
(stick) model of the foot shows a forefoot and
hindfoot, with the Achilles tendon and plantar
aponeurosis. The line of weight passes in front
of the ankle. Could you roughly estimate the
forces in the stick model of the foot? This is
quite difficult.
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We didnt do it, but the result of making a crude
ink print of the foot on graph paper and counting
squares to get the area is always interesting.
See next slide for a comparison of foot pressure
and arterial blood pressure.
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How does the sole get oxygen when standing?
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Before the cultural revolution, binding feet from
childhooddid this. The footbase is somewhat
reduced!
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STATIC POSTURAL ANALYSISThe photographs (next
slide) will remind you what you did while
describing symmetrical postures

• Left Tape measurements of joint locations
• Right Estimating angles of body segments

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Events on the right suggest a car boot sale! The
angle chart should be properly aligned in the
sagittal plane and the observers as far away as
possible. What does parallax mean?
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Lets take a closer look at the method based upon
segment angles.
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The next slide show postures which were described
using the tape measures.
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By this time, you should understand the
principles involved (many of which are common to
both methods). The next slide shows one
difference between the models.
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The methods used are suitable for a laboratory.
Photographic and optoelectronic methods would
provide refinements. It is clear why rougher
methods are preferred by ergonomists in the field
(e.g. OWAS, RULA and Posture Targetting) when
observing workers going about their business.
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THATS ALL