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Objective: The purpose of this study is to compare the workload level at each lower limbs posture and suggest the ergonomic workstation guideline for working period by evaluating the imbalanced lower limbs postures from the physiological and psychophysical points of view. Background: Many workers like welders are working in various imbalanced lower limbs postures either due to the narrow working conditions or other environmental conditions. Method: Ten male subjects participated in this experiment. Subjects were asked to maintain 3 different lower limbs postures(standing, squatting and bending) with 3 different working conditions(balanced floor with no scaffold, imbalanced floor with 10cm height of scaffold, and imbalanced floor with 20cm height of scaffold). EMG data for the 4 muscle groups(Retus Femoris, Vastus Lateralis, Tibialis Anterior, Gastrocnemius) from each lower limbs posture were collected for 20 seconds every 2 minutes during the 8 minutes sustaining task. Subjects were also asked to report their discomfort ratings of body parts such as waist, upper legs, lower legs, and ankle. Results: The ANOVA results showed that the EMG root mean square(RMS) values and the discomfort ratings(CR-10 Rating Scale) were significantly affected by lower limbs postures and working time(p<0.05). The correlation was analyzed between the EMG data and the discomfort ratings. Also, prediction models for the discomfort rating for each posture were developed using physical condition, working time, and scaffold height. Conclusion: We strongly recommend that one should not work more than 6 minutes in a standing or squatting postures and should not work more than 4 minutes in a bending posture. Application: The results of this study could be used to design and assess working environments and methods. Furthermore, these results could be used to suggest ergonomic guidelines for the lower limbs postures such as squatting and bending in the working fields in order to prevent fatigue and pain in the lower limbs body.

The study was conducted to evaluate relationships among walking velocity, heel contact velocity, and friction demand. Particularly, the study attempted to ask if two age groups (younger and older groups) differed in walking velocity and heel contact velocity, and how these gait parameters influenced friction demand characteristics in two age groups. 14 younger (7 females and 7 males, 18 to 30 years old) and 14 older (7 females and 7 males, over 65 years old) adults participated in the study. Kinematic and kinetic data were measured using 6 infrared cameras and 2 force plates mounted on the walking track. The primary goal of the study was to evaluate if walking velocity (whole body COM velocity) and heel contact velocity with advancing age influenced friction demand characteristics. The results indicated that older adults walked slower, exhibited lower heel contact velocity, and produced lower friction demand in comparison to younger adults. The study suggested that walking velocity could be a good indicator for predicting friction demand characteristics.

Objective: Two control rooms of a petroleum complex were ergonomically evaluated for this study using diverse drawings of the rooms. The objective of the study is to show the evaluation process and its results, assessment method and essential elements for drawing-based ergonomic evaluation.Background: Ergonomics can enhance the working environment and safety for a control room when implemented effectively. A control room design was examined by ergonomists based on ergonomic principles and well-practiced standards. This study was conducted because a construction consortium wanted to perform an ergonomic evaluation of the control rooms before the construction.Method: A simple evaluation process, composed with a pre-evaluation, an evaluation and a post-evaluation, was employed to carry out the study. ISO 11064, NUREG-0700, NUREG/CR-6150, and CRIOP were reviewed to evaluate the control rooms. The assessment ranges over the control room layout, workstations, display and control, environmental requirements and safety. Three ergonomists participated in the study and performed the evaluation for two months.Results: An experienced consortium of construction companies designed the petroleum complex and control rooms. No significant ergonomic design problems were detected. Quantitative recommendations were provided for the layout and workstation dimensions. Specific design directions were also proposed for environmental requirements and safety.Conclusion and Application: Design advice and minor potential problems were reported as results of the drawing-based ergonomic evaluation. More practical suggestions could be additionally provided if an on-site assessment was conducted. However, the ergonomic evaluation used in this study could be helpful and applied to designing and evaluating other various control rooms prior to their construction.