Occupational Ergonomics - Volume 3, issue 3

Authors: Ayoub, M.M.

Article Type: Research Article

Abstract: Biomechanics provide estimation of various mechanical stresses acting on the body while a person manually handles an object. Although motion analysis systems are available for dynamic biomechanical analyses, uses of such systems are mostly performed in laboratory due to high cost of the equipment and the expertise required in using them. Industrial ergonomists have limited access to dynamic biomechanical analyses. This paper reports a dynamic simulation model developed for biomechanical analyses of sagittal lifting activities. The model simulates the dynamic motion of lifting tasks for five body joints: the elbow, shoulder, hip, knee, and ankle. The inputs of the model …include initial and final joint postures; gender, weight, and height; weight of load; lifting height; and container dimensions. The output provides the angular trajectories of the five joints. The model without any video inputs predicts the motion patterns of the lift. Actual motion data were collected using 10 subjects in the laboratory for 360 lifts which included 12 lifting tasks in combination of two lifting heights, two container sizes, and three weights of load. Good results were obtained from the dynamic planar motion simulation model. The predicted motion patterns from the simulation closely resemble the observed motion pattern. Show more

Keywords: dynamic biomechanical models, motion simulation, sagittal plane lifting activities, kinematics, kinetics, optimization, trajectory

DOI: 10.3233/OER-2003-3301

Citation: Occupational Ergonomics, vol. 3, no. 3, pp. 141-151, 2003

Authors: Delleman, Nico J.

Article Type: Research Article

Abstract: At a press workstation eight industrial workers processed light-weight objects at six different combined adjustments of reach distance and working height. Working posture, workers' perceptions, and task performance were measured. Two recommendations were formulated in order to minimize the load on the musculoskeletal system: (1) the maximum reach distance is not exceeded if the object can be placed in the stamp on the press as well as be removed without bending the trunk forward, and (2) the working height should be adjusted between 5 and 10 cm above elbow height.

Keywords: musculoskeletal system, workload, posture, psychophysics, working height, reach distance

DOI: 10.3233/OER-2003-3302

Citation: Occupational Ergonomics, vol. 3, no. 3, pp. 153-164, 2003

Authors: Konz, Stephan A. | Rys, Margaret J.

Article Type: Research Article

Abstract: Industrial work environments, such as warehouses, stockrooms, supermarket checkouts, and assembly lines, often require workers to stand for long periods of time within a small area without the capability for much movement. This study summarizes the different indices used to evaluate standing work and also evaluates the various standing aids, available at the present time, to reduce the standing stress. The subjective indices of standing are discomfort/pain in the torso and, especially, the legs and feet. Physiological indices are heart rate, skin temperature of the leg, and volume changes of the leg. Standing stress can be reduced by: (1) softer …floors (i.e., mats), (2) better shoes, (3) foot rests, (4) walking, and (5) sit/stand chairs. Show more

Keywords: standing, standing aids, sit/stand chair

DOI: 10.3233/OER-2003-3303

Citation: Occupational Ergonomics, vol. 3, no. 3, pp. 165-172, 2003

Authors: Gallagher, Sean | Unger, Richard L.

Article Type: Research Article

Abstract: Vessels transiting the Panama Canal are guided through the locks using locomotives attached by means of towlines (made of wire rope), which are fastened to bitts on the deck by line handlers. The latter activity requires high pulling strength demands and is thought to be a cause of the high incidence of low back disorders in these workers. At the invitation of the Panama Canal Commission, NIOSH researchers evaluated the strength demands of line handlers and the strength capabilities of a line handling crew. Strength demands measured during a transit indicated high pulling force demands for attaching ropes to the …bow and stern bitts (< 1000 N), but lower force requirements for midships bitts (< 400 N). Tests of pulling strength capabilities of a line handling crew suggest that at least 4–5 line handlers are needed to perform the most demanding tasks. When pulling upwards or downwards on a rope in a team effort, ordering the crew according to stature appears important. Simulation of slippery deck conditions resulted in a 13% decrease in team pulling strength. Though the short duration of the study prevented an extensive evaluation, the data obtained provides insight into the design aspects of occupations where team-pulling activities are required. Show more

Keywords: ergonomics, musculoskeletal disorders

DOI: 10.3233/OER-2003-3304

Citation: Occupational Ergonomics, vol. 3, no. 3, pp. 173-184, 2003

Authors: Kwon, Young G. | Kim, Chol H. | Kim, Hong K. | Byun, Seong N.

Article Type: Research Article

Abstract: Personal protective equipment (PPE) for Korean policemen that included protective clothing, a helmet, and a shield were evaluated and redesigned based on ergonomic principles. Major functional improvements were made by reduction of equipment weight, reduction of heat stress through improvement of equipment ventilation, and improvement of usability and safety. Redesigned prototype models were made for the protective equipments. The redesigned three components of PPE are helped to enhance work performance and job safety of police officers for anti-riot operation. Currently a helmet company is trying to export newly designed helmet to other countries.

Keywords: ergonomic design, police protective equipment, shield, protective clothing, helmet

DOI: 10.3233/OER-2003-3305

Citation: Occupational Ergonomics, vol. 3, no. 3, pp. 185-195, 2003