Whole-body Vibration Measurements Research Articles

Discomfort survey of dumper operators exposed to whole-body vibration in opencast coal mines

Exposure to whole-body vibration (WBV) can lead to pain and discomfort of the heavy earthmoving machinery operators. In this paper, WBV measurement of 110 dumper operators has been conducted in three opencast coal mines, followed by a discomfort survey. Vibration measurement revealed that the mean frequency-weighted daily rms acceleration, A(8), for the operators was 0.87 m s−2. The discomfort survey was conducted to determine whether body regions of discomfort relate to their kinds of task performed by the dumper operators and also to prioritize areas for ergonomic intervention. Overall discomfort was evaluated corresponding to five regions of human body in the present survey. The results of the survey revealed that maximum operators had discomfort in their lower back region (65%) followed by leg region (53%). The industrial application of discomfort analysis is to identify the human body regions susceptible to vibration hazards. The discomfort indices are also correlated with vibration magnitude and some of the contributing factors of WBV for better understanding the vibration risks faced by the dumper operators for effectively managing the impacts of vibration in surface coal mines.

Transforming farming with intelligence: Smart vibration monitoring and alert system

During the evolution towards digital agriculture, the pivotal role of tractor riding necessitates a focus on improving operator performance and well-being. While most research has centered around vibration analysis, tangible solutions to control elevated vibration levels remain rare. The study aims to introduce an intelligent ThingSpeak-Enabled IoT (Internet of Things) solution that provides real-time monitoring and generates prompt warning alerts for tractor operators when vibrations exceed safe thresholds. The initial phase involved the real-time measurement of WBV (whole-body vibration) and SEAT (seat effective amplitude transmissibility). Following this, the secondary phase encompassed the analysis and validation of the system in cases where WBV and SEAT exceeded the recommended limits. The experimental design comprised 135 trials by systematically varying tractor ride parameters, including average speed (m/s), average depth (m), and pulling force (kN) levels. Daily vibration exposure response ranged from 0.43 m/s² to 0.87 m/s² with a mean exposure of 0.64 m/s2, surpassing the EAV (exposure action value) threshold of 0.5 m/s². The SEAT values ranged between 91.37 and 133.08 with a mean of 108.35, that indicates insufficient seat isolation capacity, i.e., < 100. Statistically, the study ascertained a significant influence of average speed and average depth WBV and SEAT responses at a 5% significance level. It underscores the potential efficacy of altering speed and depth parameters to attenuate vibration exposure levels. Further, the effectiveness of the system was tested through the automatic transmission of warning alerts via emails, text messages, and flashing red LED light on the IoT system. This critical feature provides considerable utility for tractor operators to adjust ride settings, ensuring that the ride remains within safe vibration limits. Furthermore, adopting such an advanced warning system in tractor manufacturing signifies a pioneering step towards sustainably enhancing operator well-being.

Assessment of vibration exposure of mine machinery operators at three different open-pit coal mines

In almost all branches of industry, machinery and equipment in operation cause vibration. Some sources of vibration affect only the operator's hands, fingers, and arms, while others have adverse effects on the entire -body. Various types and numbers of machines are utilized in the mining sector, and operators with them are exposed to mechanical vibrations caused by the mining machinery they use. A field study was conducted to evaluate the vibration risks to the operators using mining machines in open pit mines. Vibration levels and whole-body vibration (WBV) measurements using various types brands, and models of construction equipment were evaluated in three different mines in the west of Turkey and compared to the the criteria specified in the EU 2002/44/EC directive and ISO 2631-1 (1997) standards. The results showed that operators using mining machinery for 8 hours were exposed to WBV levels below the EU limit (1.15 m/s2), while 44% of these operators were exposed to levels above the EU action limit (0.5 m/s2). Measurement data collected from the working environment and the recommended improvements that need to be made to reduce WBV exposures are presented.

Design, Development, and Validation of a Whole-Body Vibration Measurement Device

Abstract Measurements of whole-body vibration are fundamental to access and evaluate comfort levels and possible injury development in the human being. International standards such as ISO 2631 and ISO 10326 are dedicated to the measurement and validation of mechanical systems to access vibration levels. Nowadays, the traditional measurement devices require multiple components and so hence become highly bulky, do not allow autonomous data recording, and are expensive. Following the previously mentioned standards, the present research is focused on the design and validation of a new and economic whole-body vibration measurement device. The developed device, besides being capable to measure the whole-body vibration, allows the user to select multiple sample ratings, is capable to record data on a µSD card, is easily moved and adapted, and is autonomous and low cost. This device is composed of three main components: a tri-axial accelerometer, a protective metal case, and semi-rigid rubber disc. Shaker tests were conducted to evaluate the measurement capability of the whole system and the influence of each component on the vibration measurements. This article will introduce the design and development steps for the proposed system. Concerning the validation phase, its results will be discussed and analyzed.

Exposure to Whole-Body Vibration in Commercial Heavy-Truck Driving in On- and Off-Road Conditions: Effect of Seat Choice.

Trucking is a key industry in Canada with around 180 000 professional drivers. As an industry it has a disproportionately high injury claim rate, particularly for back injuries. Whole-body vibration (WBV) can contribute to the onset and development of low back disorders, and is a well-documented exposure among driving professions. A widely adopted WBV mitigation measure focuses on hydraulic and/or pneumatic passive suspension systems both in the driver's seat and underneath the vehicle cab. Passive suspension 'air-ride' seats are the current industry standard but new technologies such as the electromagnetic active vibration cancelling (EAVC) seats offer potentially substantial improvements in WBV reduction. In this paper, we evaluate and compare four commonly used truck seats (three air-ride, one EAVC) for their vibration damping characteristics and WBV exposure attenuation in on- and off-road conditions. We recruited 24 professional truck drivers who drove 280 km (mixed on-road and off-road) in ore-haul trucks under four different seating conditions. Following the ISO 2631-1 WBV standard, vibration measurements were made on the cab floor and seat pad, and 8-h average weighted vibration (A(8)) and 8-h vibration dose values (VDV(8)) were calculated, as well as the Seat Effective Amplitude Transmissibility (SEAT), and daily vibration action limits (DVALs). These measures were compared between seat types, as well as road conditions. The EAVC seat gave best performance for both A(8) (0.27 m s-2) and VDV(8) (6.6 m s-1.75). The EVAC seat had the lowest SEAT tested (36.2%) and the longest DVAL. However, among the three passive air-suspension seats, two showed significantly reduced A(8) (0.43 and 0.44 m s-2) and VDV(8) (9.1 and 9.3 m s-1.75) exposures relative to the third passive air-suspension seats [A(8) (0.54 m s-2) and VDV(8) (11.1 m s-1.75)]. These differences in exposures among the three passive air-suspension seats resulted in varying DVAL times, with the worst performing seat reaching the DVAL after only 6.3 h of driving. There was also a seat by road type interaction; there were performance differences between the passive air-suspension seats on-road, but not off-road. The observed reduction of the WBV exposures measured from the EAVC seat was consistent with previous results. But we showed that there can also be substantive differences among seats that are the current industry standard. These differences were more evident on-road than off-road, which suggests that more work needs to be done to understand seat performance characteristics, and in matching the correct seat technology to the driving task. We demonstrated that WBV exposures in current industry conditions may exceed health-based exposure limits; this has policy relevance because WBV exposures are linked to prevalent and costly adverse health conditions in a working population that is ageing. Increased WBV measurement collection is recommended to ensure the anticipated exposure attenuations are achieved when seats are relied upon as an engineered control against WBV.

Whole-Body Vibration in Bus Drivers: Association with Physical Fitness and Low Back Pain

The aim of the study was to investigate the relationship between exposure to whole body vibration, prevalence of low back pain and level of physical fitness in bus drivers. The measurement of whole body vibration was in 100 city buses with different characteristics and the prevalence of low back pain was assessed in 200 drivers with a measurement of physical fitness level. Descriptive statistics with mean and standard deviation and inferential statistics were used with the Kurskal-Wallis test, Dunn's multiple comparisons test, Poisson regression and significance level of p &lt;0.05. The results demonstrate significant differences between the vehicle models, characterizing the conventional and articulated buses on the y and z axes with higher levels of vibration. Drivers working with conventional and articulated vehicles had a higher prevalence of low back pain with 57.5 and 60%, respectively. The level of physical fitness was low in most of the sample, however, the drivers of bi-articulated and micro bus had higher levels. Poisson regression with the outcome of low back pain, showed the factors that showed a significant prediction: age, working time, abdominal muscle resistance, lumbar strength, RMSy and RMSz.

Noise and vibration measurements in a Viking military vehicle

Noise and whole-body vibration measurements were made in a Viking military vehicle to determine the variation that should be expected during repeat measures, the effect of speed (up to 60 km/h in 5 km/h increments), and during travel over different types of terrain (comprising concrete road, gravel track and rough cross-country). Measurements were made at various crew positions (including the driver and commander) in both the front and the rear cabs in the vehicles. Three translational axes of vibration were measured in each seat. Two speeds were investigated over road (35 km/h and 55–60 km/h) and gravel (20 km/h and 35 km/h) surfaces. The effect of varying speed of the vehicle on the measured noise and vibration magnitudes was also investigated. The highest sound pressure level (LAeq) of 104 dB(A) was measured at the commander’s standing position during travel over concrete road at 55 km/h. Higher noise levels occurred for a standing commander compared with when sitting on the seat. A maximum single axis frequency-weighted vibration magnitude of 1.0 m/s2 r.m.s. was measured on the driver’s seat during travel over track at 35 km/h. Higher vibration magnitudes occurred during travel over track compared with travel over road. Both noise and vibration exposure of crew within the Viking vehicle increased with increasing speed of the vehicle.

Whole-body vibration associated with underground coal mining equipment in Australia

Environmental and logistical difficulties associated with obtaining whole-body vibration measurements from mobile equipment during operation in underground coal mines have hampered attempts to assess the potential vibration exposures associated with the use of such equipment. An alternative measurement technique was used to gather data from mobile equipment during normal operation at three low-methane coal mines and to estimate the possible magnitude of benefit of three control measures. 188 long duration measurements were obtained from shuttle cars (N = 142, median measurement duration = 3.2 h); personnel transport (N = 24, median measurement duration = 2.4 h); and materials transport vehicles (N = 22, median measurement duration = 1.8 h). Whole-body vibration amplitudes either within or exceeding the ISO health guidance caution zone were consistently measured. In particular, shuttle cars demonstrated whole-body vibration amplitudes which frequently exceeded the health guidance caution zone. The potential effects of roadway maintenance, decreased vehicle speed, and shuttle car seat replacement were found to be practically meaningful.

Non-linear characteristics of transmissibility in the dynamic responses of standing subjects exposed to vertical whole-body vibration

In this paper we studied the action of vibrations with low amplitude and high frequency on the human body, especially on the bone system, because this type of vibration is quite common for some work equipment and the effect on the workers is obvious: predisposition to bones fractures, osteoporosis, etc. For the study of vertical vibrations through the body were used oscillations at amplitudes of 1, 1.5 and 4 mm and at frequencies between 5÷35Hz. Whole-body vibration measurement was carried out with a NetdB multiple acquisition system using Piezotronics 356A16 PCB triaxial accelerators. Data was processed using dBFA Suite – Purchase and post-processing data acquisition software. The transmissibility of vibrations to the body was determined as a ratio of the mean square root of the acceleration signal received by the accelerometers (arms) to the mean square root of the signal acceleration given by the vibrant platform for three regions of the body: the knee, the lumbar region and the forehead. It was found that most arms peaks were obtained for 5÷10Hz frequencies, but there were also other frequencies for which the maximum was reached, which proves that there are more maximum accelerations specific to the position than those imposed by the vibrant platform. On the other hand, it was also found that the acceleration of transmitted vibration highly decreases compared to the acceleration given by the vibrating platform. There are important differences between the transmissibility of different people, in regard to BMI: it was found that for overweight people, transmissibility is lower than that of the normal ones.

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

ObjectiveTo determine the association between several whole-body vibration (WBV) exposure estimates and back pain-related work absence.MethodsExposures (based on the weighted daily root mean square acceleration, A(8); the daily vibration dose...

Assessment of a ride comfort number for agricultural tractors: A simplified approach

Farming activities cause operators to experience whole body vibration (WBV), which may result in back injuries. Studies have shown that despite a wide variability when operating a tractor, the accelerations arising from “ground input” have similar spectral trends making it possible to simplify and standardise the driver comfort testing procedures. Based on the recommendations of three standards on WBV measurement, a single scalar value (Ride Number – RN) has been defined and used to characterise the vibration comfort of agricultural tractors. The operation of ten tractors equipped with different damping systems on a standard test track (ISO 5008:2002) at three speeds (10, 12, 14 km h−1) has resulted in the acquisition of accelerations along the x, y and z axes at the seat. The RN was calculated by averaging the overall total values of vibration (aw) calculated for each speed. Data processing has shown that machine settings (tyre size and pressure, tractor mass) significantly affect the RN so as to achieve the recommendations for proper tractor settings. It has been observed that at each speed, the relative contribution of the components (aw10, aw12 and aw14) ranged from −12% to +11.5% showing that obtaining the RN by averaging them arithmetically was a suitable procedure. According to principal component analysis, great part of the accounted variance can be explained by accelerations acquired on the y and z axes, distinguishing between tractors with and without suspension. Thus the RN obtained can be used to compare a given tractor when provided with different equipment.

The vibration health risk assessment on operators of different capacity dumpers at opencast mine in India

In a labour intensive sector, some of the factors in the work environment which impact the health of vehicle operators include: Whole-Body Vibration (WBV) and Hand-Arm Vibration (HAV). The vibrations transferred from the dumpers are harmful to the operators; hence a study was carried out to measure the vibration from dumpers and its effect on operators in Indian opencast mines. Dumper is a vehicle designed to transport bulk material and used extensively in the construction and mining industries. For the measurement, dumpers with the different capacities were selected from the opencast mines. Vibration measurements were carried out in accordance with ISO 5349-1 for the measurement of HAV and ISO 2631-1 for the measurement of WBV. The obtained WBV exposure result shows that the problem of musculoskeletal disorder was significantly higher with respect to VDV(8) (69 %) in the exposed population as compared to A(8) r.m.s. acceleration (46 %). Moreover different capacity dumper vehicle hand transmitted vibration through steering wheel, A(8) r.m.s. acceleration observed in the range of 1.91 m/s2-4.28 m/s2. As per EU DIRECTIVE 2002/44/EC, specified Exposure Action Value (EAV) 71 % measured A(8) value falls within EAV limit. However, despite of the result operator experience problem of hand arm vibration syndrome. Hence there is a need of ergonometric deign enhancement on dumpers vehicle’s seat and steering wheel.

Assessment of Whole-Body Vibration Exposure in Mining Earth-moving Equipment and Other Vehicles Used in Surface Mining.

This study characterized whole-body vibration exposures in a set of vehicles that operate in open-pit mines and compared three different daily exposure parameters based on the ISO 2631-1:1997 and ISO 2631-5:2004 standards. Full-shift, 6 to 12-hour, continuous whole-body vibration measurements were collected from 11 representative types of vehicles in terms of hours of operation and number of vehicles used. For each type of vehicle, the exposure parameters (A(8), VDV(8), and Sed(8)) were calculated for each axis (x, y, and z), and in addition, shear or horizontal (∑xy) and vector sum (∑xyx) whole-body vibration exposure. Findings showed that: (i) substantially higher shear and vector sum whole-body vibration exposures indicated relatively high levels of exposure on the non-predominant axis; (ii) the predominant axis of exposure varied across the different type of vehicles; (iii) there were differences in whole-body vibration exposure parameters regarding the standards-based predictions of potentially adverse health outcomes (the impulsive exposure parameters VDV(8) and Sed(8) were higher and reduced acceptable vehicle operation times by one-half to two-thirds relative to A(8) exposures); and (iv) based on the predominant exposures and the time to reach daily vibration action limits, the operation of most mining vehicles would be limited to less than 8 hours a day. Differences in whole-body vibration exposure parameters impact the prediction of potentially adverse health outcomes and may introduce some uncertainty regarding how to best characterize a vehicle operator's actual exposure.

Predicting Whole-Body Vibration Exposure in Canadian Prairie Farmers.

Direct workplace whole-body vibration exposure assessment provides ecological validity for evaluating health risk in epidemiological studies, yet it is complex and expensive in practical applications. Exposure prediction modeling could be a cost-efficient alternative to directly assessing occupational vibration exposures. The objective of this study was to model directly measured whole-body vibration exposures with predictors from machinery, farm, and self-reported characteristics among Canadian prairies farmers. As per ISO 2631-1, whole-body vibration data were measured on the seat surface at three axes (x, y, z), then summarized into vector sums of the root-mean-squared (RMS) acceleration and the vibration dose value (VDV). All candidate predictors were obtained via questionnaires and onsite observations. A total of 87 whole-body vibration measurements were collected from 40 male farm workers located at 21 central Saskatchewan farms. Using log-transformed RMS and time-standardized VDV outcomes, modeling started from the bivariate analysis where predictors with P-values < 0.2 were considered eligible for multivariate analysis. With random effects of 'farm' and 'farmer', a series of mixed-effects models were constructed through the manual backward elimination method. Final models were internally validated by 1000 bootstrapped samples. The RMS model explained 47.7% of the variance in the directly measured RMS vector sum, with 42.7% obtained from five predictors of 'horsepower', 'transmission', 'vehicle year', 'jerk/jolt frequency', and 'seat bottom-out frequency', while the VDV model explained 19.5% of the variance in the directly measured VDV vector sum, with 11.6% described by the same five predictors as the RMS model. Predictive ability of the RMS model among 1000 bootstrapped samples can be anticipated to range from 14.3 to 69.1%, which may be considered adequate as exposure assessment tool for uses of epidemiological studies. The percentage of variance explained ranged from 0 to 40.5% for the VDV model, which is not robust and therefore likely not appropriate for use in survey-based exposure prediction. Whole-body vibration exposure modeling remains valuable, but is challenging in farming; the described model variance may increase with a more comprehensive list of candidate variables collected and quantified at machinery, farm, and farmer level. Predictors identified in the current and future models may provide a better understanding of how whole-body vibration exposure is modified, guide farmer's future decision on updating equipment, and allow for the development and initiation of interventions.

Measurement and evaluation of whole body vibration of agricultural tractor operator

Exposure of whole body vibration (WBV) influences performance, comfort, and long term health risks of tractor operator. Therefore, measurement and evaluation of WBV parameters should be carried out to find probable effects on the health of tractor operators. In this study, a system was designed to measure the WBV of agricultural tractor operators and evaluated the hazard risks on operator’s body according to the ISO standards, and implementation of the WBV test in the official testing station was also suggested. A tri-axial accelerometer was employed to measure vibrations transmitted to the seated operator body as a whole through the supporting surface of the buttock on four typical farm roads under different speeds. The vector sum A(8) exposures on the rough tracks (earthen and grassland roads) exceeded the action limits of 0.5 m/s2 at a 10.9 km/h forward speed and reached to the action limit value at a 16.0 km/h forward speed on the concrete road. The vector sum of VDV(8) exposures did not exceed the action limits of 9.1 m/s1.75 and was greater on the grassland road. The vector sum Sed(8) exposures values exceeded the moderate probability of an adverse health limit of 0.5 MPa on all farm roads at high forward speeds and exceeded the high probability of an adverse health limit of 0.8 MPa on asphalt, concrete, and grassland roads which should be lower than the exposure limit values as suggested by the ISO and EC standards. The WBV evaluation procedure should be considered for implementation at the official tractor test station, which would response to domestic and international tractor test regulations and improve the market competitiveness. Keywords: agricultural tractor, whole body vibration, tractor operator, driving safety, ride comfort, test standard, health risk DOI: 10.3965/j.ijabe.20171001.2113 Citation: Kabir Md S N, Chung S-O, Kim Y-J, Sung N-S, Hong S-J. Measurement and evaluation of whole body vibration of agricultural tractor operator. Int J Agric & Biol Eng, 2017; 10(1): 248–255.

Investigation and validation of consumer device accelerometers for the assessment of whole-body vibration

AbstractThere exist a discrepancy between the usage of the expensive standard accelerometer and the cheap and accessible consumer device accelerometer for the measurement of whole-body vibration (WBV). This study investigated the validity of accelerations (g-forces) obtained from a consumer device accelerometer by simultaneously using the consumer device accelerometer with a standard accelerometer during evaluation of WBV experienced by earthmoving equipment operators. The consumer device accelerometer is a software (WBV) compatible with iOS devices from operating system 5 and above (LIS331DLH, 3-axis, ±2 g acceleration range, MEMS type) while the standard accelerometer used during this study is a GCDC tri-axial accelerometer (GCDC X16-4 3-Axis, G-Force Data logger, ±18 g acceleration range, MEMS type). The two accelerometers were mounted following the basicentric axes of the seated operators and put on before earthmoving operation. Data from both the accelerometers were analysed using MATLAB. Results got...

Influence of Speed in Whole Body Vibration Exposure in Heavy Equipment Mining Vehicles

This study aimed to characterize and contrast the ISO 2631-1 daily average-continuous A(8) and cumulative-impulsive VDV(8) whole body vibration (WBV) exposures during the operation of mining heavy equipment vehicles (HEVs). In a cross-sectional study, WBV measurements were collected from six different types of HEVs. For each HEV, the daily A(8) and VDV(8) WBV exposures were determined for each axis (x, y and z) along with the vector sum (∑xyx).. The predominant axis of vibration exposure was related to and dependent on the type of HEV, which all have different average speeds. Most of the predominant axis WBV exposures were above the ISO daily vibration action limits and the vector sum-based WBV exposures were considerably higher. Our results indicated that mining HEV operators are exposed to high levels of both continuous and impulsive WBV exposures, with the impulsive WBV exposures being more restrictive with respect the HEVs daily maximum operation hours.

Measuring and Managing Workplace Whole-Body Vibration Exposures

An overview of recent research in the area of whole-body vibration measurement and management is provided. Prolonged exposure to high amplitude whole-body vibration is associated with a range of adverse health effects, particularly back pain. Operators of a range of workplace plant and equipment are exposed to the hazard. ISO2631.1 describes frequency weightings to be applied to accelerometer data and describes measures for describing vibration amplitude. An iOS application is available which may facilitate routine measurement of whole-body vibration at workplaces as a means of identifying and evaluating opportunities to reduce vibration amplitudes. Modifiable factors associated with occupational whole-body vibration exposure include the environment in which equipment is operated including roadway design and maintenance; the tasks performed using the equipment; the design of equipment including suspension and seat; equipment condition including maintenance of suspension and seating; and operator behaviour, especially speed of travel for many vehicles.

Evaluation of Whole Body Vibration and Back Pain Problem among Light Rapid Transit (LRT) Drivers

A cross sectional study was conducted to evaluate whole body vibration (WBV) and back pain problem among light rail transit (LRT) driver. This study was carried out to determine exposure level of whole body vibration and identify back pain problem due to whole body vibration exposure among LRT driver. Standardized Nordic questionnaire was used for the analysis of musculoskeletal symptoms, to identify the prevalence of back pain, information about health history, working time duration, and working experiences was obtained from 52 drivers of light rail transit (LRT) train. HVM 100 Larson Davis was used to measure whole body vibration measurement of eight LRTs with different vehicle number. The measurement of whole body vibration was done during operation working time. The data collected from HVM 100 were transferred to the Blaze software for getting the vibration magnitude of the experiment while data collected from survey were analyzed by using Statistical Package for the Social Sciences (SPSS) for statistical analysis. The analysis of graph patterns and the differentiation of magnitude value from each LRT were studied to determine the exposure level of vibration. A high prevalence of back pain (82.7%) among LRT drivers was found and high daily exposure level was obtained. The finding showed that, there are relations between back pain and daily vibration exposure which resulted in a correlation coefficient of 0.709, with significant at α = 0.05. In conclusion, it was expected that the individuals subjected to the high vibration levels would tend to report back pain.

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

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. 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. 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. 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.