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Due to increasing
concerns from the bricklaying industry, a study was conducted to determine
the biomechanical stresses on the upper extremity and lower back regarding
various size bricks used primarily in the residential housing sector.
Four different sized
bricks (Metric Modular, CSR, Max and Jumbo) were initially analyzed objectively
via videotape of the participants' work postures in a controlled environment
and on actual job sites. Additionally, approximately 100 questionnaires
were distributed to workers to obtain subjective feedback on their musculoskeletal
concerns.
Preliminary results
from the videotape analysis indicate that the midsize brick (CSR) was
the optimum brick when accounting for relative risk of injury and productivity.
Presently, a larger size brick (Max) is used primarily in the Ontario
residential sector. Analysis using the Seth et.a. (1999) model, showed
that by using the Max brick vs. the CSR there is approximately a 50% increase
in relative risk of injury to the upper extremity and only a 5% increase
in productivity.
Response rate to
the questionnaire was approximately 80%. Preliminary questionnaire results
indicate that workers' experienced elbow pain primarily in the brick hand
and more predominately wrist and hand pain (primarily arthritic type symptoms)
in the trowel hand. Further statistical analysis will be performed to
obtain more specific data from the questionnaire. Workers also reported
that they feel they have less time to complete a job and feel more tired
at the end of the day compared to a few years ago and that they did not
have sufficient recovery time.
Recommendations include
limiting the size of bricks, advocating use of the shorter trowel (no
more that 10 and a half inches) and educating the workers on proper working
postures to minimize the stress on their joints. Additionally, allowing
the workers sufficient recovery time and controlling the work pace was
seen to be important in the workers' perception of minimizing their musculoskeletal
risks.
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