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Relationships between observational estimates and physical measurements of upper limb activity (Corrigendum).
Ergonomics 2009 Sep; 52(9):1183
This paper (Ergonomics 52 (5), pp. 569-583) contains an error in the interpretation of the Hand Activity Level (HAL) rating in relation to the measured hand force duty cycle. The direct comparison of measured hand force duty cycle to the HAL rating to calculate an 'error' in the HAL rating, as shown in Figure 4 (grey bars) and described on page 575, is not valid. The valid reference standard to derive a measure of 'error' in the HAL ratings would be between the HAL rating and the HAL values specified in Table 1 of the ACGIH TLV documentation which gives an equivalent HAL based on force exertion frequency and duty cycle. The comparison of the measured hand force duty cycle to the estimated hand force duty cycle (black bars in Figure 4) to derive an error in the estimated values is valid. The four combinations of worker (2 workers) 6 job (2 jobs) were all associated with force exertion frequencies less than 0.125 exertions/sec. Measured duty cycles were 32%, 44%, 48%, and 55%. From the ACGIH documentation, the resulting Hand Activity Level would be a '1' for the job and worker combination with the duty cycle of 32% and would be undefined for the other job/worker combinations with duty cycles exceeding 40%. Since the HAL ratings averaged between 4.0 and 4.9 for all job/worker combinations, a measure of error in these ratings, if one could be determined, would be greater than that indicated in Figure 4 and described on p. 575. The statement made on p. 575, that the HAL rating more closely matched the measured duty cycle than analysts' direct estimates of duty cycle, is incorrect. The calculation of an 'error' in the HAL rating is not feasible for the range of duty cycles and exertion frequencies measured in the study. See original article: Ergonomics 2009 May; 52(5):569-583 <a href="http://dx.doi.org/10.1080/00140130802449682"target="_blank">http://dx.doi.org/10.1080/00140130802449682</a>.
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
Issue of Publication
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division