NIOSH and How Material Handling Ergonomists Research Prevent Musculoskeletal Disorders

October 11, 2016 Fork Truck Free Info 4695 Views

In a joint effort between NIOSH and the Canadian Centre of Research Expertise for the Prevention of Musculoskeletal Disorders (CRE-MSD), a detailed report about Observation-Based Posture Assessment: Review of Current Practice and Recommendations for Improvement was created.

The report helps practitioners assess working posture for the prevention and control of occupational musculoskeletal disorders (MSDs). Quantitative or semi-quantitative descriptions of posture are inputs to many job analysis tools applied in MSD prevention and control. Studies of the relationship between risk factors (such as posture, repetition, and force) and resulting MSD prevalence have used various approaches to characterizing working posture, including observation-based methods. Posture classification by systematic observation of a worker is commonly used in research and by practitioners, such as ergonomists, industrial hygienists, and safety professionals, to help inform job design decisions and establish safe work limits to reduce MSD injury risk in the workplace.

The report describes an observational approach for assessing postural stress of the trunk and upper limbs that is intended to improve risk analysis for prevention of musculoskeletal disorders. The approach is supported by several recent research studies. These studies have evaluated how much time it takes observers to classify specific trunk and upper limb postures, how frequently observers are likely to make posture classification errors, and the magnitude of these errors. The document also presents more general guidelines for the video recording of posture and for the posture analysis process.

This report describes an observational approach for assessing postural stress of the trunk and upper limbs that is intended to improve risk analysis for prevention of musculoskeletal disorders. The approach is supported by several recent research studies. These studies have evaluated how much time it takes observers to classify specific trunk and upper limb postures, how frequently observers are likely to make posture classification errors, and the magnitude of these errors. The frequency and magnitude of posture classification errors depend on how many categories (levels) are available from which to classify the specific posture. Recent studies suggest that optimal posture analysis performance is obtained by partitioning trunk flexion range of motion into 4 categories of 30° increments; trunk lateral bend into 3 categories of 15° increments; shoulder flexion into 5 categories of 30°; shoulder abduction into 5 categories of 30°; and elbow flexion into 4 categories of 30°. These categories are suggested because they optimize how rapidly and effectively analysts can visually judge posture. Information in this report can assist health/safety, ergonomics, and risk management/loss control practitioners who conduct job/ worksite assessments of lifting, pushing, pulling, carrying, and/or manual handling risk factors.

Some of the glossary used in the report:

Deferred posture analysis: Later analysis of body posture data collected (such as on video) in the workplace. This method lends itself to more detailed assessment because it allows many postures and events to be observed at the individual level.

Electrogoniometer: A device to quantify, in analog or digital form, an angle and changes of angles between body segments connected by a joint.

Mono-task work: An activity characterized by repeated stereotypical motions and exertions, without variation, usually associated with a repeating work cycle of short duration.

Parallax: A shift in the apparent relationship in position of an object when viewed along a different line of sight.

Posture analysis: Decision-making about the magnitude of a posture, relative to a convention specified in the tool or method used. For example, video can be used to record or collect body postures in the workplace. These postures can be analyzed later with software to determine the angle of the body segments, as viewed on the video.

Posture category: Any of multiple discrete intervals of angular position, usually defined by lines and/or arcs, into which a joint range of motion is partitioned.

Posture collection: The recording of postures in the workplace.

Real-time posture analysis: Observation, collection (via paper checklists or handheld devices), and analysis of body postures in the workplace while tasks are being performed (that is, in real time). Real-time posture analysis is likely to provide less detail because fewer events can be recorded simultaneously and the frequency with which dynamic events can be visually discriminated is lower.

Peak and cumulative posture assessment: Assessments of posture(s) associated with specific events within a task or job, typically to address the most severe posture adopted or the posture associated with the greatest load experienced by the worker. Cumulative assessments consider how the effect of posture and force accumulates over a specific period of work time. Note that cumulative assessments can be made of a single task or for all tasks that a job comprises, whether those tasks are the same (repetitive) or variable (non-repetitive).

Variable work: Workplace tasks that are characterized by motions and exertions that are noncyclical and without a defined work cycle.

To read the entire report go to: http://bit.ly/2ddG1OK

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