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Organizations that successfully reduce and control musculoskeletal disorders (MSDs) follow a systematic ergonomic improvement process to identify and reduce employee exposure to the risk factors known to cause MSDs. OSH management system models provide a common process for managing environmental and safety risk, particularly MSD risks. The draft ISO 45001 standard on occupational health and safety management provides another model that can be used as an effective system for managing ergonomics. This article aims to provide safety professionals, engineers, operations managers and ergonomists with an illustration and framework to systematically manage workplace ergonomics, aligned with ISO 45001.
MSD Risk Factors & Historic Approaches
For more than 300 years, history has documented injuries resulting from overuse of musculoskeletal joints from occupational risks. Ramazzini (1713/1964) first identified work-related injuries as "diseases of those who do fine work." As recently as 1917, Hamilton (1943) described a disorder called "dead fingers" affecting stone cutters using air hammers to cut and shape limestone; the disorder was a result of the effect of vibration on soft tissue. Today, numerous studies clearly define the causative risk factors and exposure thresholds of MSDs (Bernard, 1997; da Costa & Vieira, 2010; Gallagher & Heberger, 2013).
MSDs are the result of harsh wear and tear on the joint structures of the body beyond the tissues' ability to recover. Three primary risk factors cause MSDs:
*awkward posture;
*high force;
*long duration or high frequency.
The combination of two or three of these risk factors, along with an increased exposure to any or all of the factors, increases the chance of develop- ing discomfort, pain or an MSD. Several secondary risk factors also contribute to developing an MSD:
*soft-tissue compression;
*low temperature;
*vibration;
*impact stress;
*glove issues.
The threshold for each risk factor varies by body part. Larger joint structures, such as the shoulder and knee, typically have a higher tolerance for each risk factor than smaller joints such as the wrist. Epidemiologic studies provide quantitative MSD risk assessment methods enabling professionals to calculate risks based on the exposure to combined MSD risk factors (Bernard, 1997).
Programs and processes used to reduce MSDs are more recent and varied within the OSH profession. In the 1990s, OSHA and NIOSH promoted implementation of an ergonomics program that included key...