Plucky Research Tool
New system sheds light on carpal tunnel risks in poultry plants.
by T.J. Becker
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.
photo by Stanley Leary
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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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."
For more information, you may contact Dr. Robert Gregor, Department of Health and Performance Science, Georgia Institute of Technology, Atlanta, Georgia 30332-0110. (Telephone: 404/894-1028) (Email: robert.gregor@sac.gatech.edu); or Craig Wyvill, Electro-Optics, Environment and Materials Laboratory, Georgia Tech Research Institute, Atlanta, GA 30332-0823. (Telephone: 404/894-3412) (Email: craig.wyvill@gtri.gatech.edu).
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