Work - Volume 35, issue 1

Article Type: Other

DOI: 10.3233/WOR-2010-0952

Citation: Work, vol. 35, no. 1, pp. 1-2, 2010

Authors: Dunk, Nadine M. | Callaghan, Jack P.

Article Type: Research Article

Abstract: Background: Little is known about how lumbar spine movement influences mechanical changes and the potential injurious effects of prolonged flexion associated with seated postures. The purpose of this study was to examine the postural responses and pain scores of low back pain sufferers compared with asymptomatic individuals during prolonged sitting in order to understand the biomechanical factors that may be associated with sitting induced low back pain. Method: Sixteen participants with …sitting-aggravated low back pain were age- and gender-matched with 16 asymptomatic participants. Tri-axial accelerometers were used to monitor lumbar spine angles during 90 minutes of seated computer work. Lumbar spine postures were examined using a movement pattern analysis of two types of postural adjustments, termed shifts (step-like adjustments larger than 5° and fidgets (small change and return to approximately the same position). Results: The LBP group reported large significant increases (P < 0.0001) in low back pain while asymptomatic individuals reported little to no pain. On average, every participant fidgeted every 40 to 50 seconds. However, only the LBP sufferers demonstrated a significant increase (P=0.04) in the number of shifts over 90 minutes of seated work; the LBP group shifted every 4 minutes in the last 30 minutes of sitting compared to every 10 minutes for the asymptomatic group. LBP sufferers also demonstrated larger amplitudes of shifts and fidgets when compared to the asymptomatic group. Conclusion: Greater and more frequent movement was not beneficial and did not reduce pain in individuals with pre-existing LBP. Future work to understand the biomechanical effects of proactively inducing movement may help to explain the paradox of the relationship between movement and pain. Show more

Keywords: Lumbar spine, pain, seated work, movement

DOI: 10.3233/WOR-2010-0953

Citation: Work, vol. 35, no. 1, pp. 3-14, 2010

Authors: Dickey, James P. | Eger, Tammy R. | Oliver, Michele L.

Article Type: Research Article

Abstract: Background: Whole-body vibration is a significant workplace risk factor for discomfort and injury in many work sectors. The current approach for evaluating vibration exposures typically involves field studies of seatpan acceleration while the operators perform typical workplace activities. These vibration exposures are then compared to international standards to evaluate the risk of discomfort or injury. This approach does not enable systematic and controlled study of specific workplace factors such as the effect of seating, …and it is difficult and expensive to perform. Approach to paper: We have developed a systematic approach for studying whole-body vibration in the laboratory setting. This approach involves field studies of occupational exposures measuring the 6 degree of freedom chassis accelerations (translational and rotational) and replication of these exposures in the laboratory. Findings: To date, as a research team, we have collected chassis vibration data from specific vehicles in the forestry (skidders), mining (load-haul-dump vehicles), and construction (scrapers) sectors. We have processed these exposures to develop a library of representative vibration motions, and have replicated these motions in the laboratory using a robotic platform. Conclusions: This systematic approach of combining field- and laboratory-based measures has facilitated research into specific relevant questions such as the effects of multi axis vibrations on the physical risks to operator health and direct evaluation of the vibration attenuation properties of industrial seats. Show more

Keywords: Whole-body vibration, seat testing, laboratory studies, simulated vehicle operation, ergonomics

DOI: 10.3233/WOR-2010-0954

Citation: Work, vol. 35, no. 1, pp. 15-26, 2010

Authors: Eger, T.R. | Godwin, A.A. | Henry, D.J. | Grenier, S.G. | Callaghan, J. | Demerchant, A.

Article Type: Research Article

Abstract: Load haul dump (LHD) vehicles have been involved in workplace accidents resulting in fatal injuries and LHD operators also report high rates of musculoskeletal injury. Poor line-of-sight (LOS) and awkward postures adopted by the LHD operator increase the risk of driving related accidents and musculoskeletal injury. The purpose of this case study was to simultaneously measure point of regard (POR), driving posture and sitting position during the operation of a LHD in an underground mining environment …in order to further understand the link between these variables and the design of the LHD vehicle. A 5.35 m^{3} bucket LHD vehicle was used and several driving tasks were analysed. The case study results showed that despite the driving task, the operator looked to the left side of the vehicle 65% of the time. Postural implications include extreme neck rotation (> 40 degrees) for 85% of the work cycle and the average peak compression at L4/L5 was 1843N. Despite changes in driving posture the average center of pressure location for the seated operator moved very little; however changes in peak pressure were observed. The design of the LHD vehicle dictated what the operator could see, which had a direct influence on driving postures adopted by the operator and resulted in several risk factors for musculoskeletal injury. Show more

Keywords: Driving posture, load-haul-dump (LHD), point of regard (POR), pressure mapping, line-of-sight (LOS)

DOI: 10.3233/WOR-2010-0955

Citation: Work, vol. 35, no. 1, pp. 27-37, 2010

Authors: Seaman, F.A. | Albert, W.J. | Weldon, N.R.E. | Croll, J. | Callaghan, J.P.

Article Type: Research Article

Abstract: Background: The number of workplace shoulder compensation claims resulting from musculoskeletal disorders (MSDs) has decreased slightly in recent years, however the median number of days off work remains unchanged, which suggests an increase in injury severity [25]. Little information is available regarding cumulative shoulder exposures, and there is no information on their impact on shoulder pain. Methods: Seventy-nine automotive seat frame assembly workers completed a questionnaire about the prevalence and …severity of shoulder pain and were videotaped performing assembly tasks. 3DMatch, a posture-matching software program, was used to calculate the peak and cumulative shoulder moments and forces by matching postures seen in the video with predetermined ranges of posture to be used in the biomechanical model. Results: Of the 45.6% who reported shoulder pain, there was a mild correlation of pain severity with posterior shear of the shoulder. There were no significant differences in peak loads between Pain and No Pain groups; however, the No Pain group experienced significantly more cumulative caudal shear. Conclusion: Although there was no difference in percent time spent in different flexed postures between pain groups, those working some jobs may be at an increased risk of developing MSDs based on the amount of time spent in flexed postures, as well as the peak flexion moment acting on the shoulder. Show more

Keywords: Shoulder pain, cumulative load, peak load, posture, workplace

DOI: 10.3233/WOR-2010-0956

Citation: Work, vol. 35, no. 1, pp. 39-48, 2010

Authors: Grenier, S.G. | Eger, T.R. | Dickey, J.P.

Article Type: Research Article

Abstract: Background: Laboratory studies have typically been used to establish a relationship between whole body vibration (WBV) magnitude, frequency, exposure duration and reported discomfort. However, the relationship between subjective reports of discomfort, and predicted comfort response according to International Standards Organization (ISO) 2631-1, predicted health risks according to ISO 2631-1 and reported musculoskeletal discomfort has not been examined. The purpose here was to compare discomfort values predicted by ISO 2631-1 with the subjective …discomfort reported by nine Load-haul-dump (LHD) operators during typical operating conditions. Methods: Vibration exposure at the operator/seat interface was measured and processed, for one-hour duration, according to criteria established in ISO 2631-1. Vibration total values were determined for 1-minute exposure periods and the LHD operators provided a discomfort score associated with the same vibration exposure period. A linear regression analysis and correlation was carried out to determine the strength of the relationship between the predicted subjective reports of discomfort, ISO 2631-1 discomfort, objectively measured acceleration levels and reported musculoskeletal discomfort. Findings: Reported discomfort was poorly correlated to ISO discomfort scores (r=0.1799). Vibration exposure values and Musculo-Skeletal Disorder (MSD) variables were related to both ISO 2631-1 discomfort and to reported discomfort. The MSD scores produced stronger relationships with reported discomfort scores than did the vibration exposure values. Show more

Keywords: Whole-body vibration, discomfort, ISO 2631-1, equipment operators, vibration

DOI: 10.3233/WOR-2010-0957

Citation: Work, vol. 35, no. 1, pp. 49-62, 2010

Authors: Salmoni, Alan | Cann, Adam | Gillin, Kent

Article Type: Research Article

Abstract: Background: It is often difficult to access a large sample of vehicles in various work environments to evaluate worker exposure to vibration such as in construction and mining. Thus the main purpose of the present research was to test vibration exposure in a relatively large number of earth scrapers. The second aim was to assess vibration exposure values on seat transmissibility. Study Design: 33earth scrapers were assessed for both exposure to whole-body vibration and …seat transmissibility. Method: Two triaxial accelerometers, one placed on the seat and one on the floor directly below the seat, were used to gather whole-body vibration values (a_{w} ). Each machine was tested for a minimum of three complete work cycles: idling, scraping, travelling full, dumping, travelling empty back to the scrape site. Results: Results showed that idling and scraping produced low levels of vibration when compared to travelling and dumping. Second, when the a_{w} values were compared to the EU safety standards [12] for an eight hour work day, the data (z axis) exceeded the exposure action value (0.5 m/s^{2}<FORMULA>) in all machines, and the exposure limit value (1.15 m/s<FORMULA>^{2} ) in some. Implications; Operators of the scrapers were being exposed to unsafe levels of whole-body vibration. When the seats were assessed to see whether they were attenuating operator exposure to vibration, many of the seat effective amplitude transmissibility (SEAT) values exceeded 1.0. This meant that some of the seats were actually amplifying the vibration present at the floor, particularly in the y axis. Conclusion: Travelways should be kept smooth, operating speeds reduced, and new seats, effective in all three axes, designed. Show more

DOI: 10.3233/WOR-2010-0958

Citation: Work, vol. 35, no. 1, pp. 63-75, 2010

Authors: King, Gillian | Shaw, Lynn | Orchard, Carole A. | Miller, Stacy

Article Type: Research Article

Abstract: Background: There is a need for tools by which to evaluate the beliefs, behaviors, and attitudes that underlie interprofessional socialization and collaborative practice in health care settings. Method: This paper introduces the Interprofessional Socialization and Valuing Scale (ISVS), a 24-item self-report measure based on concepts in the interprofessional literature concerning shifts in beliefs, behaviors, and attitudes that underlie interprofessional socialization. The ISVS was designed to measure the degree to which …transformative learning takes place, as evidenced by changed assumptions and worldviews, enhanced knowledge and skills concerning interprofessional collaborative teamwork, and shifts in values and identities. The scales of the ISVS were determined using principal components analysis. Results: The principal components analysis revealed three scales accounting for approximately 49% of the variance in responses: (a) Self-Perceived Ability to Work with Others, (b) Value in Working with Others, and (c) Comfort in Working with Others. These empirically derived scales showed good fit with the conceptual basis of the measure. Conclusion: The ISVS provides insight into the abilities, values, and beliefs underlying socio-cultural aspects of collaborative and authentic interprofessional care in the workplace, and can be used to evaluate the impact of interprofessional education efforts, in house team training, and workshops. Show more

Keywords: Interprofessional, collaboration, socialization, instrument validation, socio-cultural

DOI: 10.3233/WOR-2010-0959

Citation: Work, vol. 35, no. 1, pp. 77-85, 2010

Authors: Mukhopadhyay, Prabir | Srivastava, Saurabh

Article Type: Research Article

Abstract: Background: Stone carving at Jaipur in Rajasthan state of India, is a traditional craft employing a large number of local youths. As an unorganized sector problems are many ranging from lack of benefits to occupational ergonomic issues of Work Related Musculoskeletal Disorders(WMSDs) and injury to body parts. Study Design: Twenty five male workers were selected in each of the three sections of a stone carving unit. The focus was to identify different ergonomic risk …factors associated in this profession from the field. Methods: Still photography and video photography was used to record different activities. Different types of non invasive tools like Rapid Entire Body Assessment (REBA), Rapid Upper Limb Assessment (RULA), Occupational Repetitive Action Index (OCRA) were used. Psychophysical measures were investigated by Body part discomfort map, rated perceived exertion scale and visual analogue scale. Objective measurements (heart arte and skin temperature) were recorded with stop watch and digital thermometer. Results: The working heart rate after 30 minutes of work was 112.4 beats per minute categorizing the work as moderately heavy. Postural analysis by REBA indicated high score (13/13). Similarly postural analysis by RULA showed high score (7/7). These indicate vulnerability of many of the postures to musculoskeletal disorders and injury. Conclusion: The study indicates that majority of the activities are in the high risk category and demands immediate ergonomic intervention in the form of tool, workstation and process design. This could be done by involving different Non Government Organizations (NGOs), political parties, and the Human Rights Department both at the center and at the state level. Show more

Keywords: Musculoskeletal disorders, ergonomic risks, posture, repetitive activities, strain index

DOI: 10.3233/WOR-2010-0960

Citation: Work, vol. 35, no. 1, pp. 87-99, 2010

Authors: Jennings, M.B. | Shaw, L. | Hodgins, H. | Kuchar, D.A. | Bataghva, L. Poost-Foroosh

Article Type: Research Article

Abstract: For older workers with acquired hearing loss, this loss as well as the changing nature of work and the workforce, may lead to difficulties and disadvantages in obtaining and maintaining employment. Currently there are very few instruments that can assist workplaces, employers and workers to prepare for older workers with hearing loss or with the evaluation of auditory perception demands of work, especially those relevant to communication, and safety sensitive workplaces that require high levels of …communication. This paper introduces key theoretical considerations that informed the development of a new framework, The Audiologic Ergonomic (AE) Framework to guide audiologists, work rehabilitation professionals and workers in developing tools to support the identification and evaluation of auditory perception demands in the workplace, the challenges to communication and the subsequent productivity and safety in the performance of work duties by older workers with hearing loss. The theoretical concepts underpinning this framework are discussed along with next steps in developing tools such as the Canadian Hearing Demands Tool (C-HearD Tool) in advancing approaches to evaluate auditory perception and communication demands in the workplace. Show more

Keywords: Hearing loss, older workers, workplace communication, auditory perception, evaluation

DOI: 10.3233/WOR-2010-0961

Citation: Work, vol. 35, no. 1, pp. 101-113, 2010