Whole-body vibration and health effects in the agricultural machinery drivers

Assessment of Comfort Variation among Different Types of Driving Agricultural Tractors: Traditional, Satellite-Assisted and Semi-Automatic

Over the past years, in the agricultural field, geo-localization has been introduced in order to develop specific farming processes, optimize resources, and reduce environmental pollution. Researchers have found alternative driving methods to traditional ones, such as assisted and semi-automatic driving. The aim of this study was to monitor the musculoskeletal efforts necessary to carry out different kinds of driving. The muscular strain was assessed using surface electromyographic devices, the distribution of the pressure exerted by the operator’s body on the seat was observed by using two barometric pads applied on the seat back and on the seat, respectively, while the body movements and postures were analyzed through a Microsoft Kinect Camera 3D acquisition system. Results showed a significantly greater muscular activation during manual and assisted driving conditions. The pressure exerted by the operator on the barometric pads was significantly higher in manual and semi-automatic driving modes than in the assisted one. A remarkable increase in the average swinging speed of examined joints was also detected, as well as the distances run by the joints in semi-automatic driving. From our study, assisted driving seems to be the best driving mode both in terms of joint economy and from the efficiency of agricultural processes.

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.

Whole-Body Vibration and Trunk Posture During Operation of Agricultural Machinery

Exposure to whole-body vibration (WBV) is common among agricultural workers and is associated with musculoskeletal health outcomes such as low back pain. Little is known, however, about the characteristics of exposure experienced during actual production practices. We measured WBV levels during agricultural machinery use among a sample of farmers (n = 55) performing routine agricultural activities and explored machinery attributes that may explain WBV summary measures. We also measured trunk posture to provide additional information about physical exposures during machinery operation. Measurements were made on-farm and during actual work conditions of a sample of agricultural machines (n = 112), including tractors, combines, heavy utility vehicles, and all-terrain vehicles (ATVs). Results indicated the presence of high levels of vibration (median frequency-weighted root-mean-square acceleration of approximately 0.8 m s-2) with time signatures that include high-amplitude mechanical shocks (median crest factor of nearly 23). Compared to other machinery types, combines exhibited the lowest WBV levels and among the most favorable trunk postures. Substantial variability was observed in both the WBV and trunk posture summary measures, suggesting for future studies that alternative sampling strategies are needed to fully capture temporal patterns of machinery use.

Whole body vibration exposure patterns in Canadian prairie farmers

Whole body vibration is a significant physical risk factor associated with low back pain. This study assessed farmers' exposure to whole body vibration on the Canadian prairies according to ISO 2631-1. Eighty-seven vibration measurements were collected with a triaxial accelerometer embedded in a rubber seat pad at the operator-seat interface of agricultural machinery, including tractors, combines, pickup trucks, grain trucks, sprayers, swathers, all-terrain vehicles, and skid steers. Whole body vibration was highest in the vertical axis, with a mean (range) frequency-weighted root mean squared acceleration of 0.43 m/s² (0.19-1.06 m/s²). Mean crest factors exceeded 9 in all 3 axes, indicating high mechanical shock content. The vertical axis vibration dose value was 7.55 m/s^1.75 (2.18-37.59 m/s^1.75), with 41.4% of measurements within or above the health guidance caution zone. These high exposures in addition to an ageing agricultural workforce may increase health risks even further, particularly for the low back. Practitioner Summary: Agricultural workers are frequently exposed to whole body vibration while operating farm equipment, presenting a substantial risk to musculoskeletal health including the low back. Assessing vibration exposure is critical in promoting a safe occupational environment, and may inform interventions to reduce farmer's exposure to vibration.

Whole-body vibration exposure of occupational horseback riding in agriculture: A ranching example

BACKGROUND

Horse riding is common in many occupations; however, there is currently no research evaluating exposure to whole-body vibration and mechanical shock on horseback.

METHODS

Whole-body vibration was measured on a cattle rancher during two 30 min horseback rides using a tri-axial accelerometer mounted on a western saddle. Vibration was summarized into standardized metrics, including the 8 hr equivalent root-mean-squared acceleration (A[8]) and the daily 4th power vibration dose value (VDV). The resulting exposures were compared to the exposure limit and action values provided by European Union Directive 2002/44/EC.

RESULTS

The highest vibration for both rides was in the vertical axis, with average A(8) and VDV of 0.56 m/s² and 26.24 m/s^1.75 , respectively. The A(8) value indicated moderate risk while the VDV suggested high risk of harmful health effects.

CONCLUSIONS

Exposure to whole-body vibration and mechanical shock during occupational horseback riding may pose deleterious health risks and increased susceptibility to low back pain. Am. J. Ind. Med. 60:215-220, 2017. © 2017 Wiley Periodicals, Inc.

A field study of exposure to whole-body vibration due to agricultural machines in a full-time rice farmer over one year

OBJECTIVES

The aims of this study were to clarify in detail the levels of whole-body vibration (WBV) exposure from a variety of agricultural machines in a rice farmer over one year, and to evaluate the daily level of exposure compared with European and Japanese threshold limits.

METHODS

The subject was a full-time, male rice farmer. We measured vibration accelerations on the seat pan and at the seat base of four tractors with various implements attached, one rice-planting machine, two combine harvesters, produced by the same manufacturer, and one truck used for transportation of agricultural machines. The position and velocity of the machines were recorded in parallel with WBV measurements. In addition, during the year starting in April 2010, the subject completed a questionnaire regarding his work (date, place, content, hours worked, machines used). We calculated the daily exposure to WBV, A(8), on all the days on which the subject used the agricultural machines.

RESULTS

The WBV magnitude in farm fields was relatively high during tasks with high velocity and heavy mechanical load on the machine, and had no dominant axis. The subject worked for 159 days using the agricultural machines during the year, and the proportion of days on which A(8) values exceeded the thresholds was 90% for the Japan occupational exposure limit and 24% for the EU exposure action value.

CONCLUSIONS

Our findings emphasize the need for rice farmers to have health management strategies suited to the farming seasons and measures to reduce WBV exposure during each farm task.

Audible and infrasonic noise levels in the cabins of modern agricultural tractors--does the risk of adverse, exposure-dependent effects still exist?

INTRODUCTION

The agricultural tractor is one of the most commonly used vehicles on farms and one of the most prominent sources of noise. This article presents an exemplary assessment of the audible and infrasonic noise levels in the cabins of selected modern wheeled agricultural tractors.

MATERIALS AND METHODS

Operator-perceived audible and infrasonic noise levels in the cabins were examined for 20 types of modern tractors during typical conditions of work. The tractors had been in use for no longer than 3 years, with rated power between 96 kW and 227 kW, designed and produced by world-renowned companies. Noise level measurements were performed in accordance with PN-EN ISO 9612:2011 (ISO 9612:2009).

RESULTS

Audible noise levels (A-weighted) ranged from 62.1 to 87.4 dB-A (average: 68.2 to 83.8 dB-A) for different work tasks. The factors influencing noise levels include performed tasks, soil, weather conditions and the skills of individual drivers. In spectrum analysis, the highest noise levels occurred at frequencies 250 Hz, 1 and 2 kHz. Infrasound noise levels (G-weighted) ranged from 87.3 to 111.3 dB-G. The driver-experienced exposure to infrasound was found to increase significantly when the vehicle was in motion.

CONCLUSIONS

Average audible noise levels have no potential to adversely affect the hearing organ during tasks performed inside the closed cabins of the analysed modern agricultural tractors. Due to the relatively low audible noise levels inside the cabins of modern agricultural tractors, non-auditory effects are the only adverse symptoms that can develop. Modern agricultural tractors emit considerable infrasonic noise levels. All tractors introduced into the market should be subjected to tests with regard to infrasonic noise levels.

Exposure to audible and infrasonic noise by modern agricultural tractors operators

The wheeled agricultural tractor is one of the most prominent sources of noise in agriculture. This paper presents the assessment of the operator's exposure to audible and infrasonic noise in 32 selected modern wheeled agricultural tractors designed and produced by world-renowned companies in normal working conditions. The tractors have been in use for no longer than 4 years, with rated power of 51 kW to up to 228 kW (as per 97/68 EC). Audible and infrasonic noise level measurements and occupational exposure analysis to noise were performed according to ISO 9612:2009 (strategy 1 - task-based measurements). The measurements were made in different typical work conditions inside and outside of tractors cabs. The results indicated that exposure levels to noise perceived by the operators (L(ex,Te) between 62,3 and 84,7 dB-A) and can make a small risk of potential adversely effects on hearing during tasks performed inside the closed cab. It should be remarked that uncertainty interval is wider and in in some conditions can occur transgression of audible noise occupational exposure limits. The measured audible noise levels can potentially develop the non-auditory effects. Analysed tractors emit considerable infrasonic noise levels that tend to exceed the occupational exposure limits (both inside and outside the driver's cab). The levels of infrasound: 83,8-111,4 dB-G. All tractors introduced for sale should be subjected to tests in terms of infrasonic noise levels. The applicable standards for low frequency noise and its measurement methods for vehicles, including agricultural tractors, should be scientifically revised. In the last years there has been a noticeable technical progress in reduction of audible noise exposure at the tractors operators workplaces with simultaneously lack of important works for limitation of exposure to infrasound. Author discuss possible health and ergonomic consequencies of such exposure.

Low frequency vibrations induce malformations in two aquatic species in a frequency-, waveform-, and direction-specific manner

Environmental toxicants such as industrial wastes, air particulates from machinery and transportation vehicles, and pesticide run-offs, as well as many chemicals, have been widely studied for their effects on human and wildlife populations. Yet other potentially harmful environmental pollutants such as electromagnetic pulses, noise and vibrations have remained incompletely understood. Because developing embryos undergo complex morphological changes that can be affected detrimentally by alterations in physical forces, they may be particularly susceptible to exposure to these types of pollutants. We investigated the effects of low frequency vibrations on early embryonic development of two aquatic species, Xenopus laevis (frogs) and Danio rerio (zebrafish), specifically focusing on the effects of varying frequencies, waveforms, and applied direction. We observed treatment-specific effects on the incidence of neural tube defects, left-right patterning defects and abnormal tail morphogenesis in Xenopus tadpoles. Additionally, we found that low frequency vibrations altered left-right patterning and tail morphogenesis, but did not induce neural tube defects, in zebrafish. The results of this study support the conclusion that low frequency vibrations are toxic to aquatic vertebrates, with detrimental effects observed in two important model species with very different embryonic architectures.

Occupational exposure to whole-body vibration and Parkinson's disease: results from a population-based case-control study

Mechanical stress producing head injury is associated with Parkinson's disease, suggesting that relations with other physical hazards such as whole-body vibration (WBV) should be tested. In this study, the authors evaluated the relation between occupational exposure to WBV and Parkinson's disease. A population-based case-control study with 403 cases and 405 controls was conducted in British Columbia, Canada, between 2001 and 2008. From detailed occupational histories and published measurements, metrics of occupational WBV exposure were constructed and tested for associations with Parkinson's disease using logistic regression and adjusting for age and sex first, and then also for smoking and history of head injury. While ever being occupationally exposed to WBV was inversely associated with Parkinson's disease (odds ratio = 0.67, 95% confidence interval: 0.48, 0.94), higher intensities had consistently elevated odds ratios, with a statistically significant effect being noted for intermediate intensities when exposures were restricted to the 10 years or more prior to diagnosis. Possible mechanisms of an inverse relation between low levels of WBV exposure and Parkinson's disease could include direct protective effects or correlation with other protective effects such as exercise. Higher intensities of WBV could result in micro-injury, leading to vascular or inflammatory pathology in susceptible neurons.

Retrospective assessment of occupational exposure to whole-body vibration for a case-control study

Occupational whole-body vibration is often studied as a risk factor for conditions that may arise soon after exposure, but only rarely have studies examined associations with conditions arising long after occupational exposure has ceased. We aimed to develop a method of constructing previous occupational whole-body vibration exposure metrics from self-reported data collected for a case-control study of Parkinson's disease. A detailed job history and exposure interview was administered to 808 residents of British Columbia, Canada (403 people with Parkinson's disease and 405 healthy controls). Participants were prompted to report exposure to whole-body vibrating equipment. We limited the data to exposure reports deemed to be above background exposures and used the whole-body vibration literature (typically reporting on seated vector sum measurements) to assign intensity (acceleration) values to each type of equipment reported. We created four metrics of exposure (duration of exposure, most intense equipment exposure, and two dose metrics combining duration and intensity) and examined their distributions and correlations. We tested the role of age and gender in predicting whole-body vibration exposure. Thirty-six percent of participants had at least one previous occupational exposure to whole-body vibrating equipment. Because less than half of participants reported exposure, all continuous metrics exhibited positively skewed distributions, although the distribution of most intense equipment exposure was more symmetrically distributed among the exposed. The arithmetic mean of duration of exposure among those exposed was 14.0 (standard deviation, SD: 14.2) work years, while the geometric mean was 6.8 (geometric SD, GSD: 4.5). The intensity of the most intense equipment exposure (among the exposed) had an arithmetic mean of 0.9 (SD: 0.3) m·s(-2) and a geometric mean of 0.8 (GSD: 1.4). Male gender and older age were both associated with exposure, although the effect of age was attenuated after adjustment for gender. The methods developed allowed us to create continuous metrics of whole-body vibration retrospectively, displaying useful variance for epidemiologic studies.

A helicopter flight does not induce significant changes in systemic biomarker profiles

Whole-body vibration and noise are inherent characteristics of helicopter operations. The helicopter pilot is affected by vibration from both low-frequency noise and mechanical vibration sources. The way this energy is transmitted to different tissues and organs depends on intensity, frequency and resonance phenomena within the body. Whole-body vibration is known to affect the muscular and skeletal system in the lower part of the spine, but less is known about the response at the cellular level to this stimulation. In some studies, chronic pathological changes have been described in different types of tissue in people exposed to low-frequency noise and vibration. The aim of the present study was to investigate possible cellular reactions to acute exposure to low-frequency noise and vibration in a helicopter. Thirteen healthy males aged 38 (18-69) years were subjected to a 3.5 h helicopter flight in a Westland Sea King Rescue helicopter. Blood tests taken before and after the flight were analysed for more than 40 parameters, including acute phase reactants, markers of leucocyte and platelet activation, complement and hemostasis markers, as well as a broad panel of cytokines, chemokines, growth factors and cell adhesion molecules. The subjects served as their own controls. With the exception of an increase in vascular cell adhesion molecule-1 (VCAM-1) during the flight, no statistically significant changes in the biomarkers were found after controlling for diurnal variation in the control blood tests, which were observed independently of the helicopter flight. In conclusion, one helicopter flight does not induce measurable changes in systemic biomarkers.

The impact of operating heavy equipment vehicles on lower back disorders

Literature reviews examining the relationship between heavy equipment vehicle (HEV) operation and the development of musculoskeletal disorders have generally been qualitative in nature and have not employed an evidence-based assessment procedure. This research determines the extent to which whole-body vibration/shock and working postures are associated with lower back and neck disorders among HEV operators, while accounting for individual (i.e. age, gender, prior history of back or neck disorders) and occupational (i.e. material handling, climatic conditions, psychosocial factors) confounders. Published articles were obtained from a search of electronic databases and from bibliographies in the identified articles. A critical appraisal of these articles was conducted using an epidemiological appraisal instrument (Genaidy et al. 2007). The meta-analysis was conducted using statistical techniques employing fixed-effect and random-effect models. Eighteen articles reporting observational studies satisfied the inclusion criteria adopted for this research. The methodological qualities of the published studies ranged from marginal to average. The meta-relative risk was found to be 2.21, indicating that operators exposed to driving HEVs are at more than twice the risk of developing lower back pain in comparison to those not exposed to driving HEVs. Therefore, it seems possible that there is a causal relationship between working as a HEV operator and development of lower back disorders. Prospective cohort studies are urgently needed to confirm the outcomes of this evidence-based methodology (based in part on the meta-analysis) and the biological plausibility should be further explored. The reported findings point to a need for improved ergonomic design of HEVs.

Measurement of Whole‐Body Vibration in Taxi Drivers

In a previous epidemiological study we reported that the prevalence (45.8%) of low-back pain (LBP) and the two-year incidence (25.9%) of LBP in 284 male taxi drivers in Japan was comparable with rates reported for other occupational drivers in which LBP frequently occurs. LBP was significantly related with the level of uncomfortable road vibrations, and, importantly, increased with total mileage. The aim of this study was to measure whole-body vibration (WBV) on the driver's seat pan of 12 taxis operating under actual working conditions. The results were evaluated according to the health guidelines in International Standard ISO 2631-1:1997. Finally, the relation between total mileage and WBV was investigated. The majority of the frequency-weighted r.m.s. accelerations of the taxis fell into the "potential health risks" zone, under ISO 2631-1:1997. It was clear that the taxi drivers were exposed to serious WBV magnitudes. Therefore, occupational health and safety management should be carried out to help prevent adverse health effects in taxi drivers. In particular, reduction of WBV in taxis and shortening of driving time to reduce duration of WBV exposure should be considered. Moreover, because many taxi drivers work 18 h every other day, the shortening of working hours and taking of rest breaks while working should be considered. Frequency-weighted r.m.s. accelerations of taxis had a tendency to decrease as total mileage increased. The relation between total mileage and WBV should be investigated by taking measurements on the floor and the back rest in addition to the seat pan.