Occupational Ergonomics - Volume 11, issue 2-3

Authors: Rodríguez, Yordán | Viña, Silvio | Montero, Ricardo

Article Type: Research Article

Abstract: Background: The number of work-related musculoskeletal disorders (WMSDs) has been increasing in industrially developing countries. Fortunately, it is possible to prevent these injuries through ergonomic assessment and job redesign. Objective: This paper presents a practical tool for non-experts in assessing exposure to risk factors for WMSDs. Methods: Evaluación del Riesgo Idividual (Individual Risk Assessment) (ERIN) is based on available ergonomic tools, epidemiological evidence and the joint International Ergonomics Association-World Health Organization project for developing WMSD risk management in developing countries. Results: ERIN focuses primarily on physical workplace factors but also includes …the workers' assessment. A scoring system has been proposed to indicate the level of intervention required to reduce the risk of injury. Preliminary tests show that ERIN is easy and quick to use, but further work is needed to establish its reliability and validity. A worksheet has also been designed for increasing the usability of the tool. Conclusions: The use of ERIN can contribute to the prevention of WMSDs in Cuba and other developing countries. Show more

Keywords: Exposure assessment, work-related musculoskeletal disorders, observation method, ergonomic tool, posture

DOI: 10.3233/OER-130210

Citation: Occupational Ergonomics, vol. 11, no. 2-3, pp. 59-73, 2013

Authors: Moore, Christopher | Nimbarte, Ashish D. | Sun, Yun

Article Type: Research Article

Abstract: Background: Manual material handling incidents are responsible for a large portion of lost work days annually. With the transition to e-commerce, cart pushing and pulling tasks have become more common. Objective: This research explored the effects of surface gradient and load on full body kinematics during cart pushing and pulling tasks. Methods: Ten participants were recruited to complete two sets of tasks. Participants performed cart pushing tasks on three surface gradients and three load masses and downhill cart pulling tasks on two surface gradients and three load masses while being recorded with an optical motion …capture system. Full body, three-dimensional joint angles were calculated for each task, and peak angles of the major body joints were analyzed using general linear models to determine the effects of the dependent variables. Results: During the cart pushing tasks, increased load mass and surface gradient both caused a significant increase in the peak joint angles of most body joints with surface gradient having the larger effect. When cart pushing and pulling tasks were compared with 5° and 10° surface gradients and three load masses, cart pushing resulted in significantly higher joint angles. Conclusion: During manual material handling tasks involving a cart, surface gradients and load masses should be minimized. Show more

Keywords: Kinematics, pushing, pulling, cart, gradient

DOI: 10.3233/OER-130208

Citation: Occupational Ergonomics, vol. 11, no. 2-3, pp. 75-84, 2013

Authors: Bendak, Salaheddine | Al-Saleh, Khalid | Al-Khalidi, Abdulsamad

Article Type: Research Article

Abstract: Background: In many developing countries, anthropometric measures are rarely available and dimensions of school furniture are either based on anthropometric measures from developed countries or are arbitrarily determined. Objective: The purpose of this study was to ergonomically assess classroom furniture dimensions in United Arab Emirates as compared to students' anthropometric measures. Methods: Relevant anthropometric dimensions of a sample of 200 grade 6 students were measured in two large schools in Dubai and Sharjah. Dimensions of furniture used by these students were also measured and compared to their anthropometric measures. Results: Results …show that there was a major mismatch between many anthropometric measures and classroom furniture dimensions. Conclusions: There is a great discrepancy between furniture dimensions and anthropometrics measures of students. To ensure postural comfort. a new set of furniture dimensions for grade 6 classrooms in is suggested based on anthropometric dimensions of students. Show more

Keywords: Anthropometry, ergonomic assessment, children, classroom furniture

DOI: 10.3233/OER-130209

Citation: Occupational Ergonomics, vol. 11, no. 2-3, pp. 85-95, 2013

Authors: Grover, Varun | Johar, Pramod | MacKinnon, Scott N. | Behm, David G.

Article Type: Research Article

Abstract: Background: Seafaring workers must contend with motions that could impact their work performance and safety. Objective: To compare and analyze the neuromuscular responses to a stable immediate environment placed in a moving (simulated wave platform motions) extended environment. Methods: Isometric maximum voluntary contraction (MVC) forces of the elbow flexors and leg extensors as well as electromyography (EMG) of the biceps brachii and vastus lateralis were recorded. The EMG activity of the triceps brachii, semitendonosis, internal obliques, and lower lumbar erector spinae muscles were also monitored during the upper and lower limb MVCs. Three types …of rotational motion (pitch, roll and mixed, all combined with a linear heave motion) created by a motion platform were randomly allocated for 1 minute each. While securely strapped and seated with the platform moving, two MVCs each were performed for the right elbow flexors and right knee extensors at the beginning and at the end of the one-minute wave motion protocol. Results: Platform motions impaired (p<0.0001) knee extension (pitch= −8%; roll=−13.4%; mixed=−13.5%) and elbow flexor MVC force (pitch=−21.1%; roll=−26.7%; mixed=−25.1%) compared to control conditions. Vastus lateralis EMG was reduced 13.3% with roll motions compared to control. Conclusions: Platform simulated wave motions can be detrimental to force production when the individual is strapped in a secure and stable seated position. Such impairments can impact the safety and work performance of employees on sea going vessels. Show more

Keywords: Stability, electromyography, marine vessels, force

DOI: 10.3233/OER-130211

Citation: Occupational Ergonomics, vol. 11, no. 2-3, pp. 97-107, 2013

Authors: Mani, Ashutosh | Musolin, Kristin | James, Kelley | Kincer, Georganne | Alexander, Barbara | Succop, Paul | Lovett, William | Jetter, William A. | Bhattacharya, Amit

Article Type: Research Article

Abstract: Background: Forty five percent of on-duty firefighter deaths every year are cardiovascular (CV) related. Heat stress and fatigue buildup are two common occupational risk factors for firefighters. These risk factors may increase the firefighters' chances of having cardiac events or even death. Objective: Buildup of heat stress and fatigue in firefighters and their recovery from these stresses during live-fire training exercises was investigated. Methods: Twenty full time firefighters, from two different fire-stations, performed live-fire training exercise constituting three real life firefighting scenarios and rest periods incorporated in between the scenarios. Core body temperature (CBT) …and heart rate (HR) were measured in real time, using an FDA approved radio pill and a polar heart rate belt. Baseline and post-scenario measurements of perceptions of physical exertion, thermal stress and respiratory distress were also collected. Results: Heart rate and CBT increased significantly with the progression of the training. The HR and CBT levels at the end of each rest period were significantly higher than the baseline values. The actual rest periods provided after each scenario were shorter than the time needed for adequate recovery. Most of the firefighters crossed the industrial limit of hyperthermia and maximum recommended level of HR elevation from baseline. Firefighters from one of the stations took micro-breaks during scenarios and were found to spend less percent time over the limit of hyperthermia. These firefighters also needed less time to recover to baseline levels of HR and CBT. Conclusions: There was significant heat stress and fatigue buildup as a result of the live-fire training exercise. Longer rest periods should be provided between scenarios to ensure recovery. Also, taking micro-breaks during a live fire training scenario might help in preventing heat stress and fatigue buildup. Show more

Keywords: Live fire training, heat stress, fatigue, recovery, micro-breaks, hyperthermia, firefighters

DOI: 10.3233/OER-130212

Citation: Occupational Ergonomics, vol. 11, no. 2-3, pp. 109-121, 2013