Lumbar-load analysis of a soldier while carrying the heavy loads

Abstract

Background: The aim of the article was to create an appropriate computer model based on the real status of the mortar operator's workplace and to analyze the workplace. After that, for any possible exceedances from the aspect of the organism's load and safety, the aim is to redesign the workplace and bring it within the limits of the permissible load, and therefore the required safety. The aim is also to identify the characteristic work movements performed by the soldier and to carry out an ergonomic analysis of the soldier's efforts and to propose appropriate improvements.

Methods: The analysis is performed on a total of 20 soldiers, from which is determined an average model of the following characteristics:  180 cm in height and 85 kg in weight. The task is to take a mine from the shell containing the mines, then transfer it to the mortar and fill the mortar barrel. The weight of the 120 mm mortar grenade is 14.8 kg. The average soldier is 26 years old and his military exercise lasts 4 hours.  The CATIA software package (Dassault Systèmes, Vélizy-Villacoublay, France) is used for analysis. By knowing the anthropometric and work environment data, with ergonomic design and analysis, the following analyses were made: biomechanical analysis, rapid upper limb assessment (RULA) and carry analysis (option from CATIA software).

Results:  The proposed modification of the position resulted in a decrease in the L4/L5  torque from 316 Nm to 154 Nm along with decreasing of the compression force on the L4/ L5 from 5,779 N to 3038 N (the compression force allowed is 3,400 N), and while the RULA analysis is from the red color position 1 (score 7; maximum load requiring rapid repositioning of such position), revised final score 4 made in yellow (a solution acceptable for this work place).

Conclusions: By ergonomic analysis, obtained proposal will lead to less chance of injury, prevention of burn out syndrome, fewer chances of illness, decreasing the fatigue, greater safety, less energy spent and better preparedness for all necessary tasks.