Iranian Journal of Ergonomics

Background and Objectives: In recent years, due to the rapid growth of metropolitan cities and the shortage of urban public transport means, including urban bus transportation, many people are forced to travel in a standing position when using these vehicles. This situation may cause pain and discomfort and non-collision injuries for passengers. The purpose of this study was ergonomic assessment of the sit-standing seat in passengers standing on urban buses.
Methods: To do this study, 8 young people with a mean age of 25.25±2.12 years were enrolled. For evaluation and assessing the effect of sit-standing seat two methods of surface Electromyography (sEMG) and Borg scale scores were applied in Fall 2018. The data was analyzed using SPSS 24.
Results: In all body parts, except for the hip, the mean scoring of Borg’s scale for perceived discomfort in sit-standing position was less than standing position. Also, the amount of contractile activity of the leg muscles in sit-standing position was significantly lower than the standing position (P<0.05).
Conclusion: Considering the results obtained from the Borg scale scores and the contraction activity of the leg muscles as a result of the use of the mentioned seat, which led to a reduction in the level of discomfort and the leg muscles contraction, it is recommended to apply the sit-stand seat instead of being in a standing position.

Background and Aim: Agricultural combine harvesters play a crucial role in cereal productions. A combine operator performs almost all harvesting activities in seated posture. As an interface of the biomechanical system of operator’s body and combines’ mechanical system, seat has major effect on operator’s safety, health, and comfort. A successful design of seat is not achievable without considering the anthropometric characteristics of user population in geometric design. In current study, the accommodation of common harvesting combines’ seat with Iranian operators’ body dimensions has been investigated.
Methods: This study was conducted in Bijar, the widest county of Kurdistan province in the west of Iran. Eight anthropometric dimensions including weight, stature, shoulder height, elbow rest height, popliteal height, buttock-popliteal length, shoulder breadth, and hip breadth were measured on a sample of operators. The accommodation of seat pan width, upper backrest width, lower backrest width, seat height, armrest height, seat depth, and backrest height were investigated based on logical equations.
Results: There was a considerable mismatch between evaluated combine seats and the anthropometric dimensions of operators. Selecting 440, 370, 440, 410, 260, 430, and 415 mm for respectively seat pan width, upper backrest width, lower backrest width, seat height, armrest height, seat depth, and backrest height can increase the match percentage to a range of 62.2% to 100%.
Conclusion: The dimensions of available combine harvester seats are not suitable for Iranian population. However, considering the anthropometric dimensions of operators can improve the seats ergonomically. It should be noted that a design based on corresponding national and international standards cannot guarantee the geometrical accommodation of seats.