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Relationships between observational estimates and physical measurements of upper limb activity.
Ergonomics 2009 May; 52(5):569-583
This study examined the internal validity of observational-based ergonomic job analysis methods for assessing upper limb force exertion and repetitive motion. Six manual tasks were performed by multiple 'workers' while direct measurements were made to quantify force exertion and kinematics of the upper limb. Observational-based analyses of force and upper limb motion/repetition were conducted by 29 professional ergonomists. These analysts overestimated the magnitude of individual force exertions - temporal aspects of force exertion ( duty cycle) were estimated more accurately. Estimates of the relative severity of repetitive motions among the jobs were accurate. Absolute counts of repetitive motions were less accurate. Modest correlations (r(2) = 0.28 to r(2) = 0.50) were observed between ratings of hand activity level and measured joint velocities. Ergonomic job analyses relying on systematic observation should be applied and interpreted with consideration given to the capabilities and limitations of analysts in estimating the physical risk factors. These findings are relevant to a better understanding of the internal validity of ergonomic job analysis methods based on systematic observation. See corrigundum: Ergonomics 2009 Sep; 52(9):1183 http://dx.doi.org/10.1080/00140130903148761.
Biological-systems; Biomechanical-engineering; Biomechanics; Body-mechanics; Cumulative-trauma; Cumulative-trauma-disorders; Ergonomics; Muscle-function; Muscle-physiology; Muscles; Muscle-stress; Musculoskeletal-system; Musculoskeletal-system-disorders; Physiological-factors; Posture; Posture; Repetitive-work; Statistical-analysis; Work-analysis; Work-environment; Worker-health; Work-operations; Work-performance; Workplace-monitoring; Workplace-studies; Work-practices; Author Keywords: repetition; force exertion; WMSD risk factors; upper limb
Brian D. Lowe, National Institute for Occupational Safety and Health, DART, 4676 Columbia Parkway, MS C-24, Cincinnati, OH 45226
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Page last reviewed: March 11, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division