Journal of School of Public Health and

---

Carpet weaving is a high risk occupation for developing MSDs, as awkward working postures, repetitive movements, contact stress and long working time are common. The objectives of the present study, which was carried out at the Iranian hand-woven carpet industry, were determination of MSDs symptoms prevalence, workstation and working posture assessment, identification of major factors associated with MSDs symptoms in different body regions and developing guidelines for workstation design. In this study, 1439 randomly selected weavers from 9 Iranian provinces have participated. Data on personal details, workshop characteristics and MSDs symptoms was collected by questionnaire. Posture and workstation assessment were performed by observational technique. The results revealed that musculoskeletal symptoms prevalence rates in shoulders (47.8%), lower back (45.2%), wrists (38.2%), upper back (37.7%), neck (35.2%) and knees (34.6%) were high as compared to general Iranian population (for neck, back and large joints p<0.0001). Working postures were found to be deviated form neutral. Lack of proper seat, leg clearance, adjustment mechanisms, together with incorrect weaving height made weavers worked in constrained, harmful postures. The results were subjected to multivariate analyses in order to find the major factors associated with musculoskeletal symptoms. Several such factors were identified for symptoms of each body regions. Identified ergonomic factors were loom type, working posture, daily working time, seat type and type of knots. Based on the results, some general guidelines for weaving workstation design were developed. The prototype test showed that the new workstation was acceptable to subject tests and improved working posture.

---

Background and Aim: There is a close relationship between working posture and workstation design so that the postural problems appear to be largely caused by improperly designed workstation. There can be no more fundamental aspect of occupational ergonomics than the concern with the design of the workstation. There is general agreement that health, well-being and productivity of workers are strongly dependent on the success of workstation design. In ergonomic design of workstation, different factors should be taken into consideration, above all posture determinant factors. Regarding this, factorial design is a very useful methodology for identifying posture determinant factors. By this methodology, workstation variables which affect working posture can be identified. Then, optimum values of these variables are determined for working posture improvement. By this means, workstation design guidelines can be developed. In this paper, which has been prepared with the aim of introducing factorial design in ergonomic studies, an example of factorial design application in developing workstation design guidelines for weaving operation is presented.
Materials and Methods: In a factorial design of 3×3, nine sets of experimental conditions were tested. The nine sets of experimental conditions consisted of different combinations of seats and weaving heights. Thirty professional weavers participated in the experiments and performed their normal weaving task in 9 experimental sessions. The effects of weaving height and seat type on postural variables were tested by Analysis of Variance (ANOVA) for Repeated Measures.
Results: The results obtained in the nine settings were compared and the setting in which optimum working posture adapted was determined. Based on the results, weaving workstation guidelines were developed.
Conclusion: It is believed that the recommended workstation improves working posture and results in reduced postural stress on weavers’ bodies and, consequently, reduced prevalence of MSDs symptoms.