The impact of operating heavy equipment vehicles on lower back disorders

Promoting safety of underground machinery operators through participatory ergonomics and fuzzy model analysis to foster sustainable mining practices

One of the most vital parameters to achieve sustainability in any field is encompassing the Occupational Health and Safety (OHS) of the workers. In mining industry where heavy earth moving machineries are largely employed, ergonomic hazards turn out to be significant OHS hazards causing Musculoskeletal Disorders (MSDs) in the operators. Nevertheless, the Indian mining industry lacks a comprehensive technique of OHS risk assessment, especially for ergonomic hazards that cause MSDs. This research appraises ergonomic hazards and develops Fuzzy Musculoskeletal-disorders Index (FMI) model to evaluate ergonomic-related MSDs. Work process and work tool ergonomic risk factors were identified through literature review and directives recommended by experts. Work posture was evaluated using RULA. The data-collecting approach was implemented using participatory ergonomic and design science principles. The FMI results show average MSDs score of 3.69, indicating high to extremely high risk. Surface plots show that combined work tool and work process was the most sensitive factors to MSDs risk compared to other two combinations. A two-sample t-test validated the FMI. The findings should help safety experts and managers develop effective OHS management plans and programmes for the sustainability of Indian mining industry.

Transport and mining machinery cabins' ergonomic evaluation as a path to its redesign

Transport and mining machinery cabins are still not well adapted to their users, while checklists for their evaluation are not common in the literature. This article proposes a new checklist for ergonomic evaluation and tests its universality empirically with a sample of 96 transport and mining machine operators. The objective of the article is two-fold. First, the article checks whether there are anthropometric dimension differences between different machines' operators. Second, statistical significance testing regarding items in the proposed checklist is performed to check its universality. Significant differences have not been found between anthropometric dimensions of transport and mining machine operators. Group comparisons prove that mining machines have better ergonomics characteristics of the chair, manual controls and vision field. The recommendation for crane designers is to examine mining machines solutions and analyze the possibility of adapting these solutions, due to anthropometric fit. Wide usage of the checklist is recommended.

Development of an intervention program to reduce whole-body vibration exposure based on occupational and individual determinants among dumper operators

Objectives. Studies related to a systematic approach for intervention design to reduce whole-body vibration (WBV) exposure are scarce. This study presents a systematic approach to identifying, selecting and prioritizing safety interventions to fulfill that research gap. Methods. A total of 130 vibration readings for dumper operators were taken from two surface iron ore mines to identify significant determinants of WBV exposure. Initially, age, weight, seat design, awkward posture, machine's age, load tonnage, dumper speed and haul road condition were hypothesized as determinants. Data were collected through standardized questionnaires and field-based observation. A multivariate statistical approach was applied for the practical use of the intervention program. Results. As some of the hypothesized factors were correlated, exploratory factor analysis (EFA) followed by multiple linear regression (MLR) was used to investigate their association with WBV exposure. As per EFA results, hypothesized factors were clubbed under individual, ergonomics and occupational factors. Occupational and ergonomics factors were found to be significantly associated with WBV exposure through MLR and used to form safety interventions to reduce WBV exposure. Conclusions. Our methodological approach is original in the occupational health research area and can be helpful to tailor the safety interventions for the unit level with minimum effort.

Are Work-Related Musculoskeletal Disorders Claims Related to Risk Factors in Workplaces of the Manufacturing Industry?

OBJECTIVES

Varied work-related musculoskeletal disorders (WMSDs) claim rates were found between companies even when they were in the same sectors with similar sizes. This study aimed to (i) identify common risk factors for back, shoulder, hand/wrist, and knee WMSDs among manufacturing jobs, and (ii) characterize the biomechanical exposures in jobs and work organizational practices between high and low WMSD claim rate companies so that more focused, industry-specific intervention strategies may be developed.

METHODS

Using historical workers' compensation data, manufacturing companies were divided into two paired groups (low and high in the lower 25%ile and higher 75%ile, respectively). On-site job evaluations were conducted in 16 companies to determine job biomechanical risk levels. Management and workers' representatives in 32 paired companies were interviewed to identify possible differences between management strategies and management/worker relationships. A total of 39 injured workers were also interviewed to gather information of self-reported injury causes and suggested preventive measures.

RESULTS

Analyses of 432 job evaluations showed that more jobs had higher risk levels of prolonged standing and heavy lifting in the high back WMSD claim rate companies than the low claim rate ones. No high biomechanical risk factors were found to be associated with jobs in high shoulder claim rate companies. High repetition, pinch force, and Strain Index were associated with high hand/wrist WMSD claim rate companies. High work pace and job stress were common among high knee WMSD claim rate companies. There were no statistically significant differences for the organizational factors between high and low WMSD claim rate companies. Heavy lifting, fast work pace, high hand/wrist repetition, high hand force, and awkward shoulder postures were identified as major contributing factors by the injured workers.

CONCLUSIONS

High WMSD claim rate companies appeared to have more high biomechanical exposure jobs than low WMSD claim rate companies. Available job evaluation methods for the low back and hand/wrists are satisfactory in quantifying job risk levels in the manufacturing industry. Research into more sensitive job evaluation methods for the shoulder and knee are needed.

Musculoskeletal Symptoms among Stone, Sand and Gravel Mine Workers and Associations with Sociodemographic and Job-Related Factors

Stone, sand and gravel mining (SSGM) constitutes the vast majority of mining operations in the United States. Despite musculoskeletal disorders being one of the most common occupational health problems across several industries, limited research has examined the extent of reported musculoskeletal symptoms or disorders among actively employed SSGM workers. To address this knowledge gap, cross sectional data were collected from 459 SSGM workers in the Midwestern United States to determine the prevalence of musculoskeletal symptoms. Sociodemographic and job-related factors were examined to identify possible risk factors in SSGM. Musculoskeletal symptoms of the low back (57%), neck (38%), shoulder (38%) and knee (39%) were highly prevalent among SSGM employees. The results, among other findings, showed that working more than 60 h a week increased the likelihood of musculoskeletal symptoms at the low back (OR: 4.7 95% CI: 1.9–11.5), neck (OR: 5.1, 95% CI: 2.2–11.8) and knee (OR: 4.5, 95% CI: 2.0–10.3). Working as a mechanic/maintenance worker increased the likelihood of low back (OR: 2.1, 95% CI: 1.1–4.2) and knee (OR: 2.2, 95% CI: 1.1–4.6) musculoskeletal symptoms. Intervention measures aimed at improving ergonomic hazard identification for various job tasks as well as administrative controls limiting hours worked may help reduce the burden of musculoskeletal problems in the SSGM industry.

A Review on Ergonomics in Agriculture. Part II: Mechanized Operations

Background: Musculoskeletal disorders (MSDs) have long been recognized as the most common risks that operation of agricultural machineries poses, thus, undermining the ability to labor and quality of life. The purpose of this investigation was to thoroughly review the recent scholarly literature on ergonomics in agricultural mechanized operations; Methods: Electronic database research over the last ten years was conducted based on specific inclusion criteria. Furthermore, an assessment of the methodological quality and strength of evidence of potential risk factors causing MSDs was performed; Results: The results demonstrated that ergonomics in agriculture is an interdisciplinary topic and concerns both developed and developing countries. The machines with driving seats seem to be associated with painful disorders of the low back, while handheld machines with disorders of the upper extremities. The main roots of these disorders are the whole-body vibration (WBV) and hand-arm transmitted vibration (HATV). However, personal characteristics, awkward postures, mechanical shocks and seat discomfort were also recognized to cause MSDs; Conclusions: The present ergonomic interventions aim mainly at damping of vibrations and improving the comfort of operator. Nevertheless, more collaborative efforts among physicians, ergonomists, engineers and manufacturers are required in terms of both creating new ergonomic technologies and increasing the awareness of workers for the involved risk factors.

Occupational risk factors for musculoskeletal disorders among railroad maintenance-of-way workers

BACKGROUND

Our objective was to examine occupational risk factors for musculoskeletal disorders of the neck, back, and knee among railroad maintenance-of-way (MOW) workers.

METHODS

Four thousand eight-hundred sixteen active, retired, and disabled members of the Brotherhood of Maintenance of Way Employes Division (BMWED) completed a survey. We computed adjusted prevalence ratios (aPRs) using Poisson regression for neck, back, and knee musculoskeletal symptoms by work exposures, adjusted for age, region, race/ethnicity, smoking, and potential second job and spare time vehicle vibration exposure.

RESULTS

Among active male BMWED members, we found associations between use of high-vibration vehicles and neck pain (aPR = 1.47, 95% confidence interval (CI): 1.07-2.03) and knee pain (aPR = 1.38, 95% CI: 1.04-1.82) for more than 1.9 years (vs 0) of full-time equivalent use; but not back pain. Back pain radiating below the knee (sciatica indicator) was associated with high-vibration vehicle use greater than 0.4 and less than 1.9 years (aPR = 1.58, 95% CI: 1.15-2.18). We also found significant associations between often or always lifting, pushing, pulling, or bending on the job (vs seldom or never) and neck pain (aPR = 2.43, 95% CI: 1.20-4.90), back pain (aPR = 1.94, 95% CI: 1.24-3.03), the sciatica indicator (aPR = 5.18, 95% CI: 1.28-20.95), and knee pain (aPR = 2.84, 95% CI: 1.47-5.51), along with positive gradients in the outcome by exposure time.

CONCLUSIONS

Biomechanical work exposures, including force and nonneutral postures, were associated with neck, lower back, and knee pain. Whole-body vibration, as measured by the duration of use of high-vibration vehicles, was associated with neck pain, knee pain, and sciatica. Prevention programs should address occupational risk factors for musculoskeletal disorders among MOW workers.

Dry cupping in the treatment of individuals with non-specific chronic low back pain: a protocol for a placebo-controlled, randomised, double-blind study

BACKGROUND

Low back pain is a very prevalent condition in the population and cupping therapy has been presented as a frequently used non-pharmacological treatment in this population. However, there is a lack of well-designed studies that evaluate the effects of this technique. This protocol describes a placebo-controlled, randomised, double-blind study that aims to evaluate the effect of dry cupping therapy on pain, physical function, trunk range of motion, quality of life and psychological symptoms in individuals with non-specific chronic low back pain.

METHODS AND ANALYSIS

Ninety individuals with chronic non-specific low back pain, aged from 18 to 59 years, will be randomised into two groups: intervention group, which will be submitted to dry cupping therapy application with two suctions; and placebo group which will undergo placebo dry cupping therapy. Both applications will occur bilaterally in parallel to the vertebrae from L1 to L5. The application will be performed once a week for 8 weeks. The volunteers will be evaluated before the treatment (T0), immediately after the first intervention (T1), after 4 weeks of intervention (T4) and after 8 weeks of intervention (T8). The primary outcome will be pain intensity, and secondary outcomes will be physical function, lumbar range of motion, patient expectation, overall perception of effect, quality of life and psychological factors.

ETHICS AND DISSEMINATION

This protocol has been approved by the Ethics Committee of FACISA/UFRN (number: 3639814). The results of the study will be disseminated to participants through social networks and will be submitted to a peer-reviewed journal and scientific meetings.

TRIAL REGISTRATION NUMBER

NCT03909672.

Development of Project Risk Management framework based on Industry 4.0 technologies

Purpose

The purpose of this paper is to identify the risks involved in the construction project based on a literature survey (LS), to develop a project risk management (PRM) framework based on Industry 4.0 technologies and to demonstrate the developed framework using Internet of Things (IoT) technology.

Design/methodology/approach

A comprehensive LS was carried out to know the different risks involved in the construction project and developed a PRM framework based on Industry 4.0 technologies to increase the effectiveness and efficiency of PRM. Heavy equipment and parameters were identified to demonstrate the developed framework based on IoT technology of Industry 4.0.

Findings

This paper demonstrates Industry 4.0 in the various stages of PRM. LS has identified 21 risks for a construction project. The demonstration of the PRM framework has identified the sudden breakdown of equipment and uncertainty of equipment as one of the critical risks associated with heavy equipment of construction project.

Research limitations/implications

The project complexity and features may add a few more risks in PRM.

Practical implications

The PRM framework based on Industry 4.0 technologies will increase the success rate of the project. It will enhance the efficiency and effectiveness of PRM.

Originality/value

The developed framework is helpful for the effective PRM of construction projects. The demonstration of PRM framework using IoT technology provides a logical way to manage risk involved in heavy equipment used in a construction project.

Whole-body vibration and back pain-related work absence among heavy equipment vehicle mining operators

Objective

To determine the association between several whole-body vibration (WBV) exposure estimates and back pain-related work absence.

Methods

Exposures (based on the weighted daily root mean square acceleration, A(8); the daily vibration dose value, VDV(8); and the daily equivalent static compression dose, Sed(8)) of 2302 workers during 4 years were estimated using each worker’s monthly vehicle operation records and WBV measurements from 11 different types of heavy equipment vehicles in a large coal mine. Company payroll data provided work absence during the concurrent 4 years of exposure. Cox regression models estimated the associations between the different WBV metrics and time to first work absence related to back pain. An adjusted R2 statistic provided a measure of model fit.

Results

All estimated metrics of WBV exposures were positively and significantly associated with back pain-related absence. HRs varied from 2.03 to 12.39 for every 0.21 m/s2 increase in the A(8)-based exposures; from 1.03 to 1.18 for every 1.72 m/s1.75 increase in VDV(8)-based exposures; and from 1.04 to 1.07 for every 0.06 MPa increase in Sed(8)-based exposures. Models using the estimated VDV(8) metric for the z axis fit the data best as measured by the R2 statistic.

Conclusion

Higher WBV exposures were associated with back pain-related absences in this population, which appears after a few years of follow-up. Introducing controls to lower exposure levels may help reduce back pain-related work absences.

Evaluation of commercially available seat suspensions to reduce whole body vibration exposures in mining heavy equipment vehicle operators

As mining vehicle operators are exposed to high level of Whole body vibration (WBV) for prolonged periods of time, approaches to reduce this exposure are needed for the specific types of exposures in mining. Although various engineering controls (i.e. seat suspension systems) have been developed to address WBV, there has been lack of research to systematically evaluate these systems in reducing WBV exposures in mining heavy equipment vehicle settings. Therefore, this laboratory-based study evaluated the efficacy of different combinations of fore-aft (x-axis), lateral (y-axis), and vertical (z-axis) suspensions in reducing WBV exposures. The results showed that the active vertical suspension more effectively reduced the vertical vibration (∼50%; p's < 0.0001) as compared to the passive vertical suspension (10%; p's < 0.11). The passive fore-aft (x-axis) and lateral (y-axis) suspension systems did not attenuate the corresponding axis vibration (p's > 0.06) and sometimes amplified the floor vibration, especially when the non-vertical vibration was predominant (p's < 0.02). These results indicate that there is a critical need to develop more effective engineering controls including better seat suspensions to address non-vertical WBV exposures, especially because these non-vertical WBV exposures can increase risks for adverse health effects including musculoskeletal loading, discomfort, and impaired visual acuity.

Exposure to whole-body vibration and hospitalization due to lumbar disc herniation

Objective

The aim was to examine if exposure to whole-body vibration (WBV) increases the risk for hospitalization due to lumbar disc herniation.

Methods

The study basis is a cohort of 288,926 Swedish construction workers who participated in a national occupational health surveillance programme from 1971 until 1992. Job title, smoking habits, body weight, height and age were registered at the examinations. Assessment of WBV were made for each of the constituent occupations by constructing a job-exposure matrix (JEM). Exposure to WBV was graded on a scale from 0 to 5. In addition, the occurrence of hospitalization due to lumbar disc herniation from January 1st 1987 until December 31st 2010 was collected from a linkage with the Swedish Hospital Discharge Register. Poisson regressions were used to estimate relative risk with 95 percent confidence intervals (95% CI), adjusting for age, height, weight and smoking, using white-collar workers and foremen as a reference group.

Results

There was an increased risk for hospitalization due to lumbar disc herniation for workers in the construction industry exposed to medium to high WBV compared to white-collar workers and foremen 1.35 (1.12–1.63). When restricting the analyses to include workers 30–49 years of age at the time of the hospital admission the risk was 1.69 (95% CI 1.29–2.21).

Conclusion

This study further supports that occupational exposure to whole-body vibration increases the risk for hospitalization due to lumbar disc herniation.

Electronic supplementary material

The online version of this article (10.1007/s00420-018-1316-5) contains supplementary material, which is available to authorized users.

Physical workload and musculoskeletal disorders in back, shoulders and neck among welders

This study aimed to determine the effect of the physical workload on the back, neck and shoulders of welders. The prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire among 15 welders. The physical workload of the neck, back and upper arms was then measured by means of inclinometry as the welders were working. The results revealed that the highest prevalence of musculoskeletal disorders during the previous 12 months was in the lower back and shoulders. The median trunk and neck flexion were significantly associated with back and neck pain in welders with symptoms during the past year (p < 0.05). Physical exposure in welders with pain was characterized by significantly more awkward postures and percentage of time spent with the trunk and neck flexed more than 20°. The nature of their work and the design of their workstations may be causes of the symptoms they experienced during work.

Full shift assessment of back and head postures in overhead crane operators with and without symptoms

OBJECTIVES

Prolonged sitting with a flexed back and neck is recognized as being associated with an increased risk of neck and back pain disorders among overhead crane operators. The aim of this study was to compare back and head postures over a full shift of work between operators who experience back and neck pain, and healthy operators.

METHODS

In a first phase, the prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire among 120 crane operators. Based on first phase results, 17 operators with back/neck disorders were matched with 15 healthy operators based on age and selected to participate in the second phase of the study. Postures and movements were continuously measured over an 8 h shift using inclinometers.

RESULTS

The highest 12-month prevalence of musculoskeletal disorders was found in the lower back, neck and knees. Case and control groups differed significantly in back and head flexion angles at the 50th percentiles APDF (p < 0.05). There was also a significant difference in the time spent working in an extreme posture of the back and head between groups (p < 0.05).

CONCLUSIONS

This is the first study to document work postures assumed during a full work shift and to compare postures between symptomatic and healthy overhead crane operators. Physical exposure in case group operators was characterized by more awkward and extreme postures in the back and head. The results of this study demonstrate that effective prevention strategies directed towards musculoskeletal disorders are required that address awkward work postures for overhead crane operators.

Association Between Whole-Body Vibration and Low-Back Disorders in Farmers: A Scoping Review

INTRODUCTION

Low-back disorders (LBDs) are the most common musculoskeletal problem among farmers, with higher prevalence rates than in other occupations. Farmers who operate tractors and other types of machinery can have substantial exposure to whole-body vibration (WBV). Although there appears to be an association between LBDs and WBV, the causal relationship is not clear.

OBJECTIVE

This scoping review investigates the association between WBV and LBDs specifically among farmers.

METHODS

Nine databases were searched using groups of terms for two concepts: 'farming' and 'low back disorder'. Screening, data extraction, and quality assessment were performed by two reviewers independently. Included studies met the following criteria: focused on adult farmers/agricultural workers; assessed exposure to operating farm machinery such tractor, combine, or all-terrain vehicle; assessed LBDs as an outcome; and reported an inferential test to assess the relationship between WBV and LBD.

RESULTS

After 276 full texts screened, 11 articles were found to analyze WBV as a risk factor for LBDs. Three were case-control, five cross-sectional, and three retrospective cohorts. Four studies showed no association between WBV and LBDs, four a positive association, and three results were mixed depending on the exposure/outcome measure.

CONCLUSION

A firm conclusion is difficult due to heterogeneity in, LBDs definition, type of farm commodity, study design, and statistical strategy. Direct comparisons and synthesis were not possible. Although retrospective cohort studies tended to show a relationship, future studies with a prospective cohort design could help clarify this association further.

Structural equation modelling of lower back pain due to whole-body vibration exposure in the construction industry

Whole-body vibration (WBV) exposure is a health hazard among workers, causing lower back pain (LBP) in the construction industry. This study examines key factors affecting LBP due to WBV exposure using exploratory factor analysis and structural equation modelling. The results confirm five key factors (equipment, job related, organizational, personal, social context) with their 17 associated items. The organizational factor is found the most important, as it influences the other four factors. The results also show that appropriate seat type, specific training programme, job rotation, workers' satisfaction and workers' physical condition are crucial in reducing LBP due to WBV exposure. Moreover, provision of new machines without proper training and good working condition might not help reduce LBP due to WBV exposure. The results help the construction companies to better understand key factors affecting LBP due to WBV exposure, and to plan for a better health improvement programme.

Health status assessment of workers during construction phase of highway rehabilitation projects around lahore, Pakistan

OBJECTIVE

The study focused on assessment of the health status of workers during construction phase of highway rehabilitation projects at six selected sites of N5 around Lahore, including Kala Shah Kaku, Muridke, Kamuki, Bhaipheru, Pattoki, and Okara.

METHODS

The study was based on multi-methods approach involving hazard identification through survey and checklist as well as a questionnaire for health status assessment and measurements of health parameters including peak expiratory flow rate (PEFR) and audiometric screening of 300 subjects.

RESULTS

The study revealed non-congenial working conditions at the sites. Noise, vibrations, dust, asphalt fumes, poor work postures, and injuries were found to be major health hazards. PEFR of most of the workers was found to be significantly lower than the reference value. Average PEFR±SEM values were 187±5.1 l/min, 178±4.3 l/min, and 266±5.3 l/min in ground preparation workers, asphalt workers, and heavy vehicle drivers, respectively. The highest rate (29%) of hearing loss was recorded among heavy vehicle drivers. Musculoskeletal problems were found to be more common among ground preparation workers.

CONCLUSION

Data revealed unsatisfactory health status of most of the workers. Direct relationship between health outcomes and the type of construction activities were observed. The current study focuses on the importance of including occupational health and safety plan in the execution phase of every developmental project that involves construction activities.

Ergonomics in the arctic - a study and checklist for heavy machinery in open pit mining

BACKGROUND

Heavy mining vehicle operators at arctic mines have a high risk of discomfort, musculoskeletal disorders and occupational accidents. There is a need for tailored approaches and safety management tools that take into account the specific characteristics of arctic work environments.

OBJECTIVE

The aim of this study was to develop a holistic evaluation tool for heavy mining vehicles and operator well-being in arctic mine environments.

METHODS

Data collection was based on design science principles and included literature review, expert observations and participatory ergonomic sessions.

RESULTS

As a result of this study, a systemic checklist was developed and tested by eight individuals in a 350-employee mining environment.

CONCLUSIONS

The checklist includes sections for evaluating vehicle specific ergonomic and safety aspects from a technological point of view and for checking if the work has been arranged so that it can be performed safely and fluently from an employee's point of view.

Association Between Farm Machinery Operation and Low Back Disorder in Farmers: A Retrospective Cohort Study

OBJECTIVE

The association between whole body vibration (WBV) as measured by annual accumulated use of all-terrain vehicles (ATV)/combine/tractor operation and low back disorders (LBDs) among farmers was investigated.

METHODS

Saskatchewan Farm Injury Cohort Study data was used. Baseline data were collected in 2007 on the three vehicle types and other factors. Follow-up data on LBD symptoms were collected during 2013 resulting in 1149 samples.

RESULTS

Adjusted for age, education, and gender, LBDs were associated with tractor operation for 1 to 150 hours/year (Relative Risk [RR] = 1.23, 95%CI 1.05 to 1.44), 151 to 400 hours/year (RR = 1.32, 95%CI 114 to 1.54) and 401+ hours/year (RR = 1.34, 95%CI 1.15 to 1.56). Additionally, hip symptoms were associated with tractor operation. Only unadjusted associations were found in combine and ATV operation.

CONCLUSIONS

Duration of tractor operation and older age are important predictors of both low back and hip symptoms in farmers.

Spine Posture and Discomfort During Prolonged Simulated Driving With Self-Selected Lumbar Support Prominence

OBJECTIVE

We examined magnitude preference, subjective discomfort, and spine posture during prolonged simulated driving with a self-selected amount of lumbar support.

BACKGROUND

The general use of lumbar supports has been associated with decreased reports of low-back pain during driving exposures; however, minimal data exist regarding occupant magnitude preference.

METHOD

Participants chose between five discrete levels of lumbar support (0-4 cm). Time-varying postural and discomfort responses were then monitored throughout 2 hr of simulated driving.

RESULTS

There were no significant effects of gender or time on posture. Women preferred larger amounts of support than men (3.25 cm ± 0.71 and 2.56 cm ± 0.88, respectively, p = .048). All participants exhibited significant increases (p = .003) in pelvic discomfort throughout the 2-hr trial regardless of the level of support chosen. Discomfort related to various aspects of the lumbar support increased significantly over time. Retrospectively, no participants desired a setting beyond 4 cm, and the majority of respondents indicate had they been able to change their initial selection, they would choose a setting between 2 and 3 cm.

CONCLUSION

The results suggest that occupants would prefer increasing the excursion capability of automobile lumbar supports beyond 2 cm.

APPLICATION

Excursion capability and adjustability of automobile lumbar supports are important features to better meet end-user preference and to reducing lumbar flexion in sitting.

Whole-body Vibration Exposure of Drill Operators in Iron Ore Mines and Role of Machine-Related, Individual, and Rock-Related Factors

Background

This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics.

Methods

The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration (m/s²)], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews.

Results

More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient β = −0.052, standard error SE = 0.023), manufacturer (β = 1.093, SE = 0.227), rock hardness (β = 0.045, SE = 0.018), uniaxial compressive strength (β = 0.027, SE = 0.009), and density (β = –1.135, SE = 0.235).

Conclusion

Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

Whole-body vibration-related health disorders in occupational medicine--an international comparison

Workers with whole-body vibration (WBV) exposure are likely to report non-specific health complaints. Health and safety providers may not recognise such occupational injuries and may be unfamiliar with appropriate exposure assessment and prevention. This is a review of clinical studies, medical evidence, differential diagnostic evaluation protocols, surveillance programmes, national and international standards, and interventions recommendations utilising PubMed and other online resources. In summary, several studies show a clear trend: with increasing duration and intensity of occupational WBV exposure, primarily musculoskeletal or neurological disorders of the spine occur. Other organ damage has also been reported. In some European Union countries, spinal injury caused by WBV is recognised as an occupational disease and may be compensable. The WBV-related injury diagnosis includes a review of the work history, exposure assessment and differential diagnostic evaluation. WBV health surveillance should assess health status of WBV-exposed workers and address preventive measures.

PRACTITIONER SUMMARY

Workers with whole-body vibration exposure report a variety of physical disorders. Health and safety providers may not recognise such injuries, or may be unfamiliar with exposure assessment and prevention. This review addresses health issues, exposure assessment and an international review of compensation criteria, trends and prevention efforts.

Low-back pain

Low-back pain is one of the most common painful conditions experienced by humans throughout their life. Some occupational risk factors (namely, heavy manual material handling) may also contribute to the development of low-back pain: due to the high prevalence of both low-back pain and manual material handling in the adult working population, it has been estimated that low-back pain is probably the most common occupational disorder worldwide. Lifetime prevalence of low-back pain has been reported to be as high as 84%, depending on the case definition used, and no age group is spared, even children. Although low-back pain is not a lethal condition, it was estimated at the third rank among all diseases by disability-adjusted life-years in 2010 in the USA, after ischemic heart disease and chronic obstructive pulmonary disease, and at the first rank by years lived with disability. It also ranked high (13th) globally for the same year, in disability-adjusted life-years. Low-back pain is currently classified as nonspecific/specific as to putative cause and as acute (lasting less than 6 weeks), subacute (6-12 weeks), or chronic (more than 12 weeks) according to duration of symptoms. The distinction between nonspecific/specific and acute/subacute/chronic low-back pain is useful not only for epidemiologic studies, but also (mainly) for choosing the appropriate strategy for the diagnosis and treatment of the disorder. Workplace risk factors for low-back pain include manual lifting and whole-body vibration exposure. This chapter will provide an overview of modern concepts of low-back pain (in general) and will then outline some distinctive features of work-related low-back pain.

Psychological distress and pain reporting in Australian coal miners

Background

Coal mining is of significant economic importance to the Australian economy. Despite this fact, the related workforce is subjected to a number of psychosocial risks and musculoskeletal injury, and various psychological disorders are common among this population group. Because only limited research has been conducted in this population group, we sought to examine the relationship between physical (pain) and psychological (distress) factors, as well as the effects of various demographic, lifestyle, and fatigue indicators on this relationship.

Methods

Coal miners (N = 231) participated in a survey of musculoskeletal pain and distress on-site during their work shifts. Participants also provided demographic information (job type, age, experience in the industry, and body mass index) and responded to questions about exercise and sleep quality (on- and off-shift) as well as physical and mental tiredness after work.

Results

A total of 177 workers (80.5%) reported experiencing pain in at least one region of their body. The majority of the sample population (61.9%) was classified as having low-level distress, 28.4% had scores indicating mild to moderate distress, and 9.6% had scores indicating high levels of distress. Both number of pain regions and job type (being an operator) significantly predicted distress. Higher distress score was also associated with greater absenteeism in workers who reported lower back pain. In addition, perceived sleep quality during work periods partially mediated the relationship between pain and distress.

Conclusion

The study findings support the existence of widespread musculoskeletal pain among the coal-mining workforce, and this pain is associated with increased psychological distress. Operators (truck drivers) and workers reporting poor sleep quality during work periods are most likely to report increased distress, which highlights the importance of supporting the mining workforce for sustained productivity.

Occupational driving as a risk factor for low back pain in active-duty military service members

BACKGROUND CONTEXT

Although occupational driving has been associated with low back pain, little has been reported on the incidence rates for this disorder.

PURPOSE

To determine the incidence rate and demographic risk factors of low back pain in an ethnically diverse and physically active population of US military vehicle operators.

STUDY DESIGN/SETTING

Retrospective database analysis.

PATIENT SAMPLE

All active-duty military service members between 1998 and 2006.

OUTCOME MEASURES

Low back pain requiring visit to a health-care provider.

METHODS

A query was performed using the US Defense Medical Epidemiology Database for the International Classification of Diseases, Ninth Revision, Clinical Modification code for low back pain (724.20). Multivariate Poisson regression analysis was used to estimate the rate of low back pain among military vehicle operators and control subjects per 1,000 person-years, while controlling for sex, race, rank, service, age, and marital status.

RESULTS

A total of 8,447,167 person-years of data were investigated. The overall unadjusted low back pain incidence rate for military members whose occupation is vehicle operator was 54.2 per 1,000 person-years. Compared with service members with other occupations, motor vehicle operators had a significantly increased adjusted incidence rate ratio (IRR) for low back pain of 1.15 (95% confidence interval [CI] 1.13-1.17). Female motor vehicle operators, compared with males, had a significantly increased adjusted IRR for low back pain of 1.45 (95% CI 1.39-1.52). With senior enlisted as the referent category, the junior enlisted rank group of motor vehicle operators had a significantly increased adjusted IRR for low back pain: 1.60 (95% CI 1.52-1.70). Compared with Marine service members, those motor vehicle operators in both the Army, 2.74 (95% CI 2.60-2.89), and the Air Force, 1.98 (95% CI 1.84-2.14), had a significantly increased adjusted IRR for low back pain. The adjusted IRRs for the less than 20-year and more than 40-year age groups, compared with the 30- to 39-year age group, were 1.24 (1.15-1.36) and 1.23 (1.10-1.38), respectively.

CONCLUSIONS

Motor vehicle operators have a small but statistically significantly increased rate of low back pain compared with matched control population.

Effects of vibration in forced posture on biochemical bone metabolism indices, and morphometric and mechanical properties of the lumbar vertebra

Epidemiological studies have shown a relatively strong association between occupational lower back pain (LBP) and long-term exposure to vibration. However, there is limited knowledge of the impact of vibration and sedentariness on bone metabolism of the lumbar vertebra and the mechanism of bone-derived LBP. The aim of this study was to investigate the effects of vibration in forced posture (a seated posture) on biochemical bone metabolism indices, and morphometric and mechanical properties of the lumbar vertebra, and provide a scientific theoretical basis for the mechanism of bone-derived LBP, serum levels of Ca(2+), (HPO4)(2-), tartrate-resistant acid phosphatase (TRAP), bone-specific alkaline phosphatase (BALP), and bone gla protein (BGP),the pathological changes and biomechanics of lumbar vertebra of New Zealand white rabbits were studied. The results demonstrate that both forced posture and vibration can cause pathological changes to the lumbar vertebra, which can result in bone-derived LBP, and vibration combined with a seated posture could cause further damage to bone metabolism. Serological changes can be used as early markers for clinical diagnosis of bone-derived LBP.

Low back pain

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization’s International Classification of Functioning, Disability, and Health (ICF). The purpose of these low back pain clinical practice guidelines, in particular, is to describe the peer-reviewed literature and make recommendations related to (1) treatment matched to low back pain subgroup responder categories, (2) treatments that have evidence to prevent recurrence of low back pain, and (3) treatments that have evidence to influence the progression from acute to chronic low back pain and disability.

Individual participant data meta-analysis of mechanical workplace risk factors and low back pain

OBJECTIVES

We used individual participant data from multiple studies to conduct a comprehensive meta-analysis of mechanical exposures in the workplace and low back pain.

METHODS

We conducted a systematic literature search and contacted an author of each study to request their individual participant data. Because outcome definitions and exposure measures were not uniform across studies, we conducted 2 substudies: (1) to identify sets of outcome definitions that could be combined in a meta-analysis and (2) to develop methods to translate mechanical exposure onto a common metric. We used generalized estimating equation regression to analyze the data.

RESULTS

The odds ratios (ORs) for posture exposures ranged from 1.1 to 2.0. Force exposure ORs ranged from 1.4 to 2.1. The magnitudes of the ORs differed according to the definition of low back pain, and heterogeneity was associated with both study-level and individual-level characteristics.

CONCLUSIONS

We found small to moderate ORs for the association of mechanical exposures and low back pain, although the relationships were complex. The presence of individual-level OR modifiers in such an area can be best understood by conducting a meta-analysis of individual participant data.

The role of past and current strenuous physical work in the association between professional car driving and chronic low-back syndromes: a population-based study

STUDY DESIGN

Population-based cross-sectional study of clinically assessed low back syndromes.

OBJECTIVE

To investigate whether exposure to professional car driving, either alone or in combination with strenuous physical work is associated with clinically defined sciatica or other clinically diagnosed chronic low back syndromes.

SUMMARY OF BACKGROUND DATA

Several studies have found an association between professional driving and back disorders, but drivers' histories of heavy physical work tasks has rarely been taken into account.

METHODS

The nationally representative sample comprised of 2323 men aged 30 to 64 (the Health 2000 Survey). The diagnoses of sciatica and chronic low back syndromes were based on a standardized clinical examination by specially trained physicians. Life-long exposure to professional car driving and to physically demanding work was assessed retrospectively via interviews. Logistic regression was used to estimate the risk of clinical chronic low back syndromes related to these exposures, and the risks were presented with odds ratios (OR) with 95% confidence intervals (95% CI).

RESULTS

The prevalence of physician-diagnosed sciatica was 5.4% and that of other chronic low back syndromes 4.0%. Professional car driving in general was associated with sciatica at an OR of 1.42 (95% CI 0.92-2.18) and with other chronic low back syndromes at an OR of 1.31 (0.80-2.16), after adjustment of covariates and strenuous physical work. Exposure to driving without exposure to physical work was not associated with the outcomes, whereas driving in combination with strenuous physical work increased the risk for sciatica threefold (3.22; 1.86-5.59), and that of low back syndromes twofold (2.08; 1.12-3.87).

CONCLUSION

The increased risk of low back disorders related to professional car driving is more likely due to strenuous work tasks rather than to driving itself.

Vibration and shock exposure of maintenance-of-way vehicles in the railroad industry

The aim of this study is to investigate and compare vibration and shock measurements of maintenance-of-way vehicles used in the railroad industry for track maintenance and construction. Following international standards (i.e., ISO 2631-1: 1997) and professional guidelines the frequency weighted root-mean-square (r.m.s.) acceleration for each measurement axis, the vector sum, the seat effective amplitude transmissibility (SEAT), the crest factor (CF), the maximum transient vibration value (MTVV), the vibration dose value (VDV), the ratio and the newly proposed shock risk estimation factor 'R' for spinal injury according to ISO 2631-5:2004 were measured and calculated for seven different maintenance-of-way vehicles during revenue service. Furthermore, a proposed alternative spinal injury prediction method, the VibRisk model, which incorporates different typical driver postures and operator physical characteristics was included for comparison with the ISO 2631-5 risk prediction. The results of the vibration exposure measurements depended on vehicle type, track/surface conditions and seat properties, with the tamper and bulldozer showing the highest r.m.s. vibration values. The vector sum (a(v)) results ranged from 0.37 to 0.99 (m/s(2)). Five of seven track maintenance vehicles would exceed the current Whole-body Vibration ACGIH-TLV(®) guideline for an 8 h exposure duration in the vertical axis recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The measured CF, MTVV/a(w) and VDV/(a(w)·T(1/4)) ratios were at or above the critical ratios in the majority of measurements given by the ISO 2631-1 (1997) and American industry guidelines by the American Conference of Governmental Industrial Hygienists (ACGIH-TLV). Comparing both prediction models for vibration shock risk for parts of the lumbar spine, different risk predictions and inconsistencies were found. The VibRisk model generally suggests different and higher risk of vertebral endplate failure for individual lumbar levels, whereas the ISO 2631-5 model indicated generally lower risks and did not differentiate between different disk levels and driver posture. Epidemiological studies validating the different shock risk models are lacking. Work modifications and adequate suspension seats would be beneficial for prevention of harmful exposure to vibration and shocks.

Whole body vibration exposures in forklift operators: comparison of a mechanical and air suspension seat

Using a repeated measures design, this study compared differences in whole body vibration (WBV) exposures when 12 forklift operators drove the same forklift with a mechanical suspension and an air suspension seat. A portable PDA-based WBV data acquisition system collected and analysed time-weighted and raw WBV data per ISO 2631-1 and 2631-5 WBV measurement standards. Tri-axial measurements of weighted vibration (A(w)), crest factor, vibration dose values, time-weighted average-peak, raw (+) peak, raw (-) peak and static compression dose (S(ed)) were compared between seats. There were significant differences in z-axis WBV exposures with the air suspension seat, yielding lower WBV exposures. In addition, there were differences between seats in how they attenuated WBV exposures based on the driver's weight. In the mechanical suspension seat, WBV exposures were weight-dependent, with lighter drivers having higher WBV exposures, whereas with the air suspension seat, the same trends were not as prevalent. STATEMENT OF RELEVANCE: This study contributes to the understanding of how different seat suspensions can influence WBV transmission and how some components of vibration transmission are dependent on the weight of the driver. Additional systematic studies are needed to quantify how various factors can influence WBV exposures.

The performance of computer input devices in a vibration environment

This study investigates the performance of a touch screen, mouse and trackball in a motion environment. A Stewart motion platform was used to generate a six-degree-of-freedom motion environment. Participants were placed in an environment where vehicle vibration was simulated. Tasks were used according to Fitts' Law to obtain the movement time, error rate, index of performance and throughput of each input device. The results showed that during static conditions, the touch screen gave the best results. However, in the vibration environment, the mouse gave the best results. The trackball is the worst of the three. The error rate and end-point variation tends to increase for the touch screen in the vibration environment. STATEMENT OF RELEVANCE: This study investigates the performance of a pointing device in a vibration environment. The results showed that during static conditions, the touch screen gave the best results. However, in the vibration environment, the mouse gave the best results. The track ball is the worst of the three. This research achievement can help human-computer interaction design in various dynamic environments such as in sea and land vehicles.

Neck pain combined with arm pain among professional drivers of forest machines and the association with whole-body vibration exposure

The purpose of this study was to investigate the existence of neck pain and arm pain among professional forest machine drivers and to find out if pain were related to their whole-body vibration (WBV) exposure. A self-administered questionnaire was sent to 529 forest machine drivers in northern Sweden and the response was 63%. Two pain groups were formed; 1) neck pain; 2) neck pain combined with arm pain. From WBV exposure data (recent measurements made according to ISO 2631-1, available information from reports) and from the self-administered questionnaire, 14 various WBV exposure/dose measures were calculated for each driver. The prevalence of neck pain reported both for the previous 12 months and for the previous 7 d was 34% and more than half of them reported neck pain combined with pain in one or both arms. Analysis showed no significant association between neck pain and high WBV exposure; however, cases with neck pain more often experienced shocks and jolts in the vehicle as uncomfortable. There was no significant association between the 14 WBV measures and type of neck pain (neck pain vs. neck pain combined with arm pain). It seems as if characteristics of WBV exposure can explain neither existence nor the type of neck pain amongst professional drivers of forest machines. The logging industry is important for several industrialised countries. Drivers of forest machines frequently report neuromusculoskeletal pain from the neck. The type of neck pain is important for the decision of treatment modality and may be associated with exposure characteristics at work.