Observation-based posture assessment : review of current practice and recommendations for improvement

Disclaimer This guidance document is not a standard or regulation, and it creates no new legal obligations. It contains recommendations and descriptions of practices that have been shown to enhance observation-based assessment of working posture. The recommendations presented are advisory in nature, informational in content, and intended to assist occupational safety and health practitioners in providing a safe and healthful workplace. To receive documents or other information about occupational safety and health topics, contact NIOSH: EXECUTIVE SUMMARY 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 flex-ion 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. This report also presents more general guidelines for the video recording of posture and for the posture analysis process. Guidelines for video recording address such factors as camera position, field of view, lighting, and duration of recording. Guidelines for posture analysis address enhancements such as the benefits of digital video, computer software, training, and use of visual reference and perspective cues. Information in this report can assist health/safe-ty, ergonomics, and risk management/loss control practitioners who conduct job/ worksite assessments of lifting, pushing, pulling, carrying, and/or manual handling risk factors. GLOSSARY 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 …

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