The Biomechanical Overload of the Rachis in Push and Pull Activities: Historical Revision, State of the Art and Future Prospects in the Light of the New High-Sampling Digital Dynamometers and the Multitask Features of Work in the Workplace

摘要

The risk of biomechanical overload for the rachis is characterized by two different exposure situations: lifting of loads and push and pull of carts or objects. If in the first case the risk is determined by the continuous and repeated compression of the intervertebral disks, in the second case the damage is generated differently by lateral-lateral and anteroposterior cutting forces acting on the disk. The study of the risk caused by Towing and Driving activities was based on three main areas: epidemiological studies, psychophysical studies and physiological studies developed mainly since the 1970s and continued until today. The most concrete reference to these investigations is, however, the famous study that uses the psychophysical approach conducted in the Liberty Mutual Research labs for more than 25 years, synthesized in 1991 by Snook and Ciriello and integrated by Mital et al. (1993). Substantially, the psycho-physical study of Snook and Ciriello that generated the resulting tables is performed to determine how risk factors can influence the maximum acceptable forces during a working day. The problem with these studies is the correct identification by the operator of its real tolerance limit, and the absence of evidence of direct correlation with health disorders during work. Keeping these references today, through sophisticated instruments, but with good price, is possible to obtain a significant amount of relevant information from the measurements that describes in a much deeper way the working conditions. Last but not least, it is necessary to expand the calculation of the risk index in push and pull activities which must adequately describe the different working conditions that occur on the working day. A proposal consistent with the formula N.I.O.S.H. of multiple tasks defines a computational scenario similar to the multitask, proposed by Waters Thomas, Putz-Anderson v. Garg A., End LJ, in the ergonomics publication "Revised niosh equation for the design