On Site Analysis of the Muscular Load during Three Car Assembly Tasks

This study describes the on site analysis of the muscular load during car assembly operations which involve opening or closing the bonnet. Car assembly involves 21 of these operations but three were selected as representative for analysis of muscular load of the lower back and shoulder muscles. Each cycle of a task lasted about 50 seconds, but was subdivided into a number of subtasks. Subjects were asked to report the most annoying and most strenuous subtasks.The first task was mounting the support bar for the bonnet of the car, and was subdivided into eight smaller operations. The second task was mounting the windscreen wipers and was divided into 6 subtasks. The third task, mainly involving adjusting the lights, was divided into five parts.Two subjective screening methods (NIOSH 1991, RULA) and two objective methods (EMG processing and video digitalisation) were used for data analysis. Due to the limitations of the NIOSH 1991 equation in these situations, we determined a Recommended Weight Limit (RWL) o...