Georgia Tech's Research Horizons magazine - April 1998
Plucky Research Tool
New system sheds light on carpal tunnel risks in poultry plants
by T.J. Becker
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A new application of existing technology, the
Ergonomic Work Assessment System (EWAS) measures the wrist
position, cutting forces and muscle exertion used by poultry
workers as they debone chicken.
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Computer users are not the only folks risking carpal tunnel syndrome.
This cumulative trauma disorder also occurs in the poultry industry,
where cutting tasks require workers to make highly repetitive motions.
Researchers
at the Georgia Institute of Technology are studying the problem with
their own computerized system that monitors workers' motions during
processing
operations.
A new application of existing technology, the Ergonomic Work Assessment
System (EWAS) was developed by Georgia Tech's Agricultural Technology
Research Program (ATRP). The system measures the wrist position, cutting
forces and muscle exertion used by poultry workers as they debone chicken.
"
EWAS provides a wealth of data about how muscles are called upon to
perform tasks — information that can be used both to boost efficiency
on the factory floor and to correct inefficient movements and awkward
postures leading to injuries," says J. Craig Wyvill, director of
ATRP and a researcher in the Electro-Optics, Environment and Materials
Laboratory of the Georgia Tech Research Institute.
EWAS gathers information via several independent components: A miniature
force transducer mounted on a knife blade measures the force and torque
(twisting force) applied when workers make a cut. Electromyographic (EMG)
surface sensors, placed on a worker's arms, measure how much muscle exertion
is required for the cutting task, while an electrogoniometer measures
wrist angle. All of these sensors are linked to a portable computer that
uses custom software to store the resulting measurements and produce graphical
summaries. Because data is sent to the same computer at the moment action
happens, researchers are able to study relationships between force, exertion
and posture.
"
This is a big step forward in ergonomics research," says Dr. Robert
J. Gregor, head of Georgia Tech's Department of Health and Performance
Science. Gregor, who directed modifications made to the original EWAS
design, explains: "Now we can quantify the environment — we
can assign a number to something that has previously been described in
qualitative terms as 'difficult.' With EWAS, we can determine exactly
how difficult by measuring conditions as the task is being performed."
These measurements, in turn, can be used to improve the workplace.
For example, a different knife handle or blade might reduce movement of
the wrist or reduce the force required to perform a task. The angle of
attack might be altered, the position or height required to perform a
certain task might be changed, or workers might be rotated more often
from a difficult task.
Ergonomics, also referred to as human factors engineering, is the science
dealing with people and their workplace. This multi-disciplinary field
is becoming more important as work processes shift dramatically, placing
new demands on the human body.
Repetitive motions involving the wrists and hands often put workers
at risk for carpal tunnel syndrome. This cumulative trauma disorder occurs
when tendons in the wrist become inflamed. Symptoms include: burning,
tingling or numbness in the fingers; discomfort in the wrist, forearm
or upper arm; and difficulty in gripping.
"
Workers across different industries today are faced with tasks that
must be performed fast and which use highly repetitive motions," Wyvill
says. "Workers are often at risk of injury unless they take periodic
breaks from the activity or find ways to reduce the stress and repetition
of the job. EWAS can help in identifying when that break needs to take
place."
Besides helping prevent injuries in the workplace, EWAS can also be
used to boost productivity. "The online feedback of force application,
posture and muscular effort would allow employees to develop greater skills
that would reduce physical stress and improve their efficiency," says
Ron Jones, ergonomics manager at Gold Kist Inc., a poultry processing
firm headquartered in Atlanta that was one of the testing sites for EWAS.
Although it's initially being tested in poultry plants, EWAS can be
used in a variety of industries. Its sensors can be adapted to virtually
any tool — ranging from keyboard operation to heavy manual tasks.
Mobility is another major benefit. Because of its compact size, EWAS
can easily be taken into a plant so that testing can be done in the actual
environment, rather than having to replicate the environment in the laboratory.
Laboratory testing has its benefits, but there is also a downside.
"
Sometimes you're so obtrusive when taking measurements that the task
being examined is no longer realistic," says Dwight Waddell, a Georgia
Tech research engineer working with EWAS. "The next thing you know,
you're taking interesting data, but it really has nothing to do with what
workers do every day on the factory floor."
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