Iran Occupational Health

Background and aims: Workload can be defined as the operator's required capacity to meet a special level of performance while performing a task. Optimized workload is a point at which any increase or decrease could have negative effects on operator's performance. Therefore, the aim of this study was to assess the workload using subjective and objective methodologies in the assembly lines of a car manufacturing company.  

Methods: This is a cross-sectional and descriptive-analytical study. In the first phase, among assembly line workers of one of the car manufacturing industries, operators with heavy and very heavy jobs where selected by using the Borg scale. In the next phase, the workload of selected workers was assessed by Subjective (NASA-TLX) and Objective (SI, REBA) workload assessment tools. Data were analyzed by SPSS version 11/5.

Results: Results of NASA-TLX showed that performance and physical demands with mean scores of 89/23 and 86/92 were respectively the most important and mental workload with mean score of 49/23 was the least important dimensions. Furthermore, working stations with high workload have obtained high scores by observational tools as well. Adaptive Weighted Workload (AWWL) was positively associated with strain index score for right hand, which means that any increase of workload can result to an increase of strain index score of right hand.

Conclusion: It was revealed that workload was high in assembly lines. This result was also confirmed by observational evaluation.  Based on our results, workload management programs should be focused on omitting or reducing improper working postures.