Occupational Ergonomics - Volume 13, issue S1

Authors: Strasser, Helmut

Article Type: Research Article

Abstract: BACKGROUND: The paper is a printed version of keynotes and plenary addresses which have been presented during international ergonomics conferences to which the author had been invited. It focuses on human work performance influenced by an advanced age. Aging of the workforce, productivity, or work and health, today must be regarded as important research topics for ergonomics and for realizing age-differentiated work design. OBJECTIVE: A scientific survey of the various human performance potentials impacted by age. METHODS: A comprehensive literature review of scientific papers dealing with age-dependent work performance was carried out. The …results were garnished with suitable aphorisms, sentences and wisdoms on age which stem from wise old men and prominent philosophers and poets. RESULTS: The results comprise physical age-related performance potentials, e.g., muscle strength and assembly performance. Also the impact of age on vision and on the hearing is described in detail and it is visualized in figures and tables. Furthermore, important age-dependent changes in the central nervous system and in mental-cognitive performance areas are reported. Fortunately, also positive issues of aging on the working performance could be detected. The paper ends with a meditative discourse about length and quality of life. CONCLUSIONS: Age-differentiated work design has to be based on specific knowledge about age-dependent performance potentials of the employees. A comprehensive literature review revealed a lot of already existing and sustainable facts which can be applied in work design. However, further fundamental and especially applied research is necessary since today substantial changes in the working conditions occur very quickly. Show more

Keywords: Ergonomics and the control system “work”, literature review, age-related performance changes, wisdoms on age, length and quality of life

DOI: 10.3233/OER-170250

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 1-24, 2017

Authors: Dutta, Koumi | Basu, Bibaswan | Sen, Devashish

Article Type: Research Article

Abstract: BACKGROUND: Motorbikes are a cost effective and fuel efficient mode of transport but at the same time they account for huge number of Road Traffic Accidents (RTA). Bike riders are exposed to postural, psychosocial stress which may lead to accidents. OBJECTIVES: Objectives of the study are to: (1) quantify postural and psychosocial stress which may be contributory factors to accident and injury; (2) record the magnitude of aggression, sensation level and risky behaviour to employ behaviour based safety (BBS). METHODS: Healthy male motor bike riders (n = …150) were randomly taken to identify consumer purchase behaviour, assess postural stress, perceived pain and exertion. Perception of riders with respect to their safety was recorded. Magnitude of aggression, sensation and risky behaviour were also recorded among bike riders (n = 35). RESULTS: Result showed drivers experienced pain in low back (84%), thigh (82.67%), hand (81.33%), neck (68.67%) and shoulder (63.33%). Riders (62.67%) perceived the exertion as ‘hard and heavy’, 24.67% as ‘very hard’ and 12.67% as ‘somewhat hard’. Majority of the riders preferred looks and style, neglecting physiological comfort and safety. Magnitude of aggression, sensation and risky behaviour among bike riders were notably high. CONCLUSIONS: Quantification of these stressors is essential to implement engineering revision and behaviour based safety. Show more

Keywords: Motor bike riders, postural stress, psychosocial stress, behaviour

DOI: 10.3233/OER-170251

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 25-36, 2017

Authors: Chowdhury, Nabila | Aghazadeh, Fereydoun | Amini, Milad

Article Type: Research Article

Abstract: BACKGROUND: There is an extensive body of research reviewing the ergonomics needs of industrial office workers. However, very few studies have considered evaluating the working postures of students or professors in universities who are exposed to prolonged sitting while working at a computer workstation. OBJECTIVE: The purpose of the study was threefold: (1) to determine the major ergonomic issues university employees encounter while working at computer workstations, (2) to compare the two ergonomic assessment tools (RULA and REBA) to see how similarly or differently they assess the risks present in the same working condition and (3) …to develop a model that correlates working condition, work posture and computer workstation design with their negative effects on musculoskeletal system. METHODS: This research was constituted of a comprehensive survey (5 minutes) and a quantitative risk assessment session (20 minutes) conducted over 72 university personnel and their workstations in a university workplace. Along with a pre-assessment questionnaire; the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) and two ergonomic assessment tools namely Rapid Entire Body Assessment (REBA) and Rapid Upper Limb Assessment (RULA) were used to quantify the ergonomic risk factors. To evaluate the computer workstations “OSHA Computer Workstations eTool-Evaluation Checklist” was used. RESULTS: The upper limbs of computer workstation users seem to be more prone to Work-related Musculoskeletal Disorders (WMSD) and Repetitive Stress Injuries (RSI) symptoms. In 85.5% of cases, RULA scores were the same or more than that of REBA, which indicates work of office employees may cause a disorder more in the upper limbs than the lower limbs. CONCLUSIONS: Alignment of the monitor was found to be the most significant design parameter. Among different body parts, trunk was the most affected one, as a result of poor posture and/or workplace design followed by shoulder and upper arm, and forearm and wrist. Show more

Keywords: Workstation design, awkward posture, RULA, REBA, office work

DOI: 10.3233/OER-170252

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 37-46, 2017

Authors: Al-Qaisi, Saif | Aghazadeh, Fereydoun

Article Type: Research Article

Abstract: BACKGROUND: The torque required to manually turn a handwheel-valve typically exceeds operators’ capabilities, requiring them to use a valve-wrench. Although valve-wrenches are commonly used, an ergonomic wrench has not yet been developed. OBJECTIVE: To introduce an ergonomically designed valve-wrench and evaluate it with respect to conventional valve opening methods. METHODS: Four methods were compared including: bare hands, restricted conventional wrench (assumes presence of obstructions), unrestricted conventional wrench, and ergonomically-modified wrench. Each method was performed at two torque settings, 15 Nm and 30 Nm. Electromyography activities were measured from eight trunk and shoulder muscles. …The time to fully open the valve and Borg-ratings were recorded for each method. RESULTS: The modified wrench resulted in the lowest average time and Borg-rating; however, these averages were not significantly different from the averages of the unrestricted conventional wrench. The method that was associated with the lowest overall electromyography activities was restricted conventional wrench, followed subsequently by bare hands, modified wrench, and unrestricted conventional wrench. CONCLUSIONS: Although the ergonomically-modified wrench was associated with relatively high electromyography activities, it was the most time-efficient method, allowing the muscles to sustain physical loads for shorter periods of time. Overall, participants rated this method as the least physically demanding. Show more

Keywords: Handwheel, valve operation, valve-wrench, electromyography (EMG), torque

DOI: 10.3233/OER-170253

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 47-58, 2017

Authors: Teixeira, Leonor | Talaia, Mário | Meles, Bruna

Article Type: Research Article

Abstract: BACKGROUND: Thermal discomfort is mentioned as one of the major causes of dissatisfaction in workplaces when people are exposed to extremely hot or cold thermal environments in the industrial context. Studies evaluating the comfort of the thermal environment are becoming increasingly important, but this kind of studies is time-consuming and it becomes expensive and difficult to implement for many organizations. OBJECTIVE: The purpose of this study was to evaluate thermal comfort in a metalworking industry located in Portugal, applying user-friendly thermal indexes supported by real data collected using inexpensive measuring tools. METHODS: To …this end, this study was conducted using objective measurements of air temperature T ( ∘ C), and relative humidity RH (%), collected using a pen data acquisition (Easy Log USB). Simultaneously, subjective answers about the perception of thermal comfort by the workers in the section studied were collected based on a questionnaire survey. RESULTS: The results revealed a high risk of heat stress for some workstations, which required the intervention of the Health and Safety Department. CONCLUSIONS: The indexes applied in this work, namely the WMO diagram and the EsConTer index, offer a sound model for thermal stress risk evaluation, minimizing difficult and time-consuming investigations to identify thermal comfort problems in workplaces, each emphasizing particular aspects, in order to create value. Show more

Keywords: Ergonomics, thermal comfort, WMO diagram, EsConTer index, effective temperature index

DOI: 10.3233/OER-170254

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 59-70, 2017

Authors: Aghazadeh, Fereydoun | Amini, Milad

Article Type: Research Article

Abstract: BACKGROUND: There is an extensive body of research reviewing the effect of task factors on the Maximum Acceptable Weight of Lift (MAWL) or heart beats elevation as a result of a manual material handling task. However, there are now studies that investigate the effect of task factors on the heart rate recovery time (HRR). OBJECTIVE: The purpose of the study was twofold: (1) to determine the HRR for a series of lifting tasks based on the activity heart rate and by using a set of task variables, (2) to compare the effect of three task factors …on the HRR following a lifting task. METHODS: This research was constituted of capturing the duration that heart rate needs to get to a steady state following a lifting task, along with conducting the survey of perceived exertion (Borg). Three independent variables of this study (task-factors) were weight of the lift (10 and 20 kg), frequency of the lift (6 and 9 lifts per minute), and the duration of the lift (5 and 10 minutes). Given the possible treatment combinations, a total of 8 treatments was obtained. Twenty-four university male students performed the lifting tasks in a between-subject design. Each participant performed one treatment by lifting a box from knuckle to shoulder height at a certain frequency, duration and weight. All eight treatments were equally replicated with three observations per treatment group. RESULTS: Increasing weight and frequency of the lift significantly increased the HRR (respectively by 37% and 34%), while the HRR had a slight decrease when duration was doubled (approximately - 2.7%). Weight of the lift was the only factor led to a significant change in the perceived difficulty of the task among participants (approximately 20%). CONCLUSIONS: Among main factors, frequency and weight of the lift had a significant effect on the HRR (p-values < 0.1). Among the interaction effects, the interaction of frequency and duration had a significant effect on the HRR. The only factor that had a significant effect on the Borg-rating was weight of the lift (p-value < 0.1). Show more

Keywords: MMH, lifting task, recovery time, exertion

DOI: 10.3233/OER-170255

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 71-80, 2017

Authors: Nadon, Alicia L. | Cudlip, Alan C. | Dickerson, Clark R.

Article Type: Research Article

Abstract: BACKGROUND: Manual patient handling completed by nurses can include unexpected or strenuous exertions, potentially leading to injury. Lifting guidelines focus on mitigating primarily limiting low back exposures, and the influence of these techniques on the shoulder is unknown. OBJECTIVE: To quantify shoulder loading during manual patient handling tasks and determine whether approaches intended to limit low back exposures negatively affect shoulder demands. METHODS: Twenty novice university-aged females completed five manual patient handling tasks before and after a training session. Participants simulated handling a partial weight bearing patient, and joint load magnitudes were calculated. …Strength demands were interpreted in the context of available population capability ranges. RESULTS: Using recommended techniques decreased peak low back loading in most scenarios (p = 0.01–0.02), but had variable effects on shoulder loading. Peak loading in the shoulders increased by 97–107% in the Sit-to-Chair task following training. Using recommended techniques for Turn Toward decreased mean population strength requirements at the back to 35% of capability while increasing shoulder requirements to 100% capability. CONCLUSIONS: Recommended manual patient handling techniques mitigate low back exposures but likely transfer demands to other body regions, specifically the shoulder. Show more

Keywords: Nursing, manual patient handling, upper extremity, joint loading

DOI: 10.3233/OER-170256

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 81-90, 2017

Authors: Ladouceur, Michel | Westhaver, Ian A. | Kozey, John W.

Article Type: Research Article

Abstract: BACKGROUND: Laser imaging provides an alternative to manual measurements in the collection of general anthropometric surveys focused on 1-D measures. This study aimed to develop a systematic method of comparing manual and digital anthropometric measurements and validate a commercial three-dimensional laser scanner for anthropometric measurements. OBJECTIVE: The purpose of this preliminary project is to validate a laser scanner for selected length and girth measurements. METHODS: A variety of linear and circumferential segmental measures from 20 participants were either extracted from a 3D commercial laser imaging device scans or measured manually. Error between manual and scan-extracted …measurements was compared based on ISO20685, and clinical standards. Regression analysis improved the quality of the measurements and residuals were again compared to the standards. RESULTS: After regression, 7 of the 9 the measurements were within, or close to (two times standard), standards. Error was caused by a combination of image quality issues associated with the laser scanner, as well as algorithmic issues associated with larger participants. CONCLUSIONS: Overall, the results are promising, and given the indicated population, a small number of minor improvements may very quickly allow the scanner to collect measurements on a clinical population. Show more

Keywords: Anthropometry, laser scanning, validation

DOI: 10.3233/OER-170257

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 91-103, 2017

Authors: Boucher, Danielle R. | Oliver, Michele L.

Article Type: Research Article

Abstract: BACKGROUND: Joystick operators often experience constant low level muscle loading in the upper limb when using joysticks, which can lead to repetitive strain injuries. It has been hypothesized that the strain on the muscles may be reduced by supporting the arm during joystick manipulation. OBJECTIVE: To design a horizontally dynamic armrest which appropriately supports the motion of the forearm during side-to-side joystick movements. METHODS: The paper describes the process used to design a dynamic armrest which appropriately supports an operator’s arm throughout the range of side-to-side joystick movements. RESULTS: The trajectory …of the elbow and wrist during these joystick movements was determined, and a new horizontally dynamic armrest designed and built. CONCLUSIONS: Most heavy mobile equipment seat armrests fail to provide appropriate support throughout the range of joystick motion resulting in constant upper body muscle loading. Our paper describes the development of a dynamic armrest which is designed to provide appropriate support throughout side-to-side joystick movements. Show more

Keywords: Joysticks, armrests, ergonomics, design

DOI: 10.3233/OER-170258

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 105-113, 2017

Authors: Ngô, Valérie Tuyêt Mai | Nadeau, Sylvie | Hallé, Stéphane

Article Type: Research Article

Abstract: BACKGROUND: Ever deeper mining is exposing workers to increasing heat and humidity, which can threaten their health and safety. OBJECTIVE: The objective of this research is to create a matrix of criteria that will eventually be used to design a personal cooling vest that will meet the needs and wants of miners. METHODS: A literature review was done to identify the constraints and requirements of miners in ultra-deep mining conditions; a field study was conducted in which information was acquired by measurement (temperature, humidity), observation (work rate) and semi-directed interviews of a …convenience sample, 20 volunteer participants (age, weight, height, shirt size, personal protective equipment currently worn and opinion about a cooling vest). The data was then structured, compiled and interpreted to create a matrix. RESULTS: Participants were found to be in the > 50% percentile of the population regarding weight and height. All reacted positively to the idea of a cooling vest to help in their work. A matrix containing nine users and seven design-related criteria was created. CONCLUSIONS: The matrix must still be tested as to its validity. Its usage could then be extended to other fields of work in which heat is a health and safety concern for workers. Show more

Keywords: Ultra-deep mining, cooling equipment, ergonomic criteria

DOI: 10.3233/OER-170259

Citation: Occupational Ergonomics, vol. 13, no. S1, pp. 115-126, 2017