Critical survey on the biomechanical criterion in the NIOSH method for the design and evaluation of manual lifting tasks

摘要

In 1981, the National Institute for Occupational Safety and Health (NIOSH) published a comprehensive guide for the evaluation and design of manual lifting, based on epidemiological, physiological, psychophysical, and biomechanical knowledge. Arevised version of the easy-to-use "NIOSH lifting equation" was provided in 1991 considering occasional new findings from literature. For assessing the load on the lumbar spine during lifting, a limit of 3.4 kN for lumbosacral disc compression wasintroduced. Regarding this biomechanical criterion, several inconsistencies and discrepancies are revealed when comparing the NIOSH substantiation approaches and the respective data of the literature sources: For example, essential results referred to byNIOSH or NIOSH-authorized presenters are not included in or cannot be reproduced from the cited sources. Furthermore, the epidemiological studies showing the relationships between low-back disorder incidence rates and lumbar mechanical exposures cannot be used for confirming the 3.4 kN value as an appropriate limit. It is concluded that the 3.4 kN criterion is substantiated neither epidemiologically nor biomechanically by the provided sources. More comprehensive data compilations, available in themeantime, may be regarded as a better background for the derivation of lumbar load limits in order to diminish the individual overexertion risk during manual materials handling.