Whole-body Vibration Exposure Research Articles

Letter to the Editor: Landsbergis et al (2019) Titled "Work Exposures and Musculoskeletal Disorders Among Railroad Maintenance-of-Way Workers".

Letter to the Editor: Landsbergis et al (2019) Titled "Work Exposures and Musculoskeletal Disorders Among Railroad Maintenance-of-Way Workers".

Role of whole-body vibration exposure and posture of dumper operators in musculoskeletal disorders: a case study in metalliferous mines

Objectives. The combined role of whole-body vibration (WBV) exposure and awkward posture on musculoskeletal disorders (MSDs) experienced by dumper operators in two metalliferous mines in India was evaluated through a cross-sectional study. Methods. Frequency-weighted root mean square (rms) acceleration was used for WBV exposure assessment. Anthropometry and rapid upper limb assessment (RULA) were used for static and dynamic posture assessment, respectively. Prevalence of MSDs was assessed using the Nordic musculoskeletal questionnaire (NMQ). Logistic regression was used to assess the factors contributing to MSD problems. Results. The rms values revealed that the operators exceeded the lower limit of Standard No. ISO 2631-1:1997. The dynamic posture study revealed that the majority of dumper operators were taking awkward postures and 58–74% of them were subjected to high and medium levels of MSD risk. The adjusted odds ratio (7.96, 95% confidence interval [1.24, 41.35]) for the most awkward postures revealed WBV exposure as the significant risk factor for MSD problems among the operators. Conclusion. WBV exposure and posture of operators should be regularly monitored and corrective actions implemented to reduce their MSD problems. Ergonomic seat design based on the anthropometry of the operators should be assessed at the time of procuring new equipment.

A methodology for assessment of long-term exposure to whole-body vibrations in vehicle drivers to propose preventive safety measures

Introduction: The appearance of musculoskeletal disorders (MDs) in professional drivers due to exposition to whole-body vibration (WBV) makes it relevant to assess this exposure. The European Directive 2002/44/EC has two methods to evaluate exposure to WBV (defined in ISO2631-1:2008). These methods evaluate the exposure associated with an 8-hour working day; however, MDs due to WBV could also be caused by accumulated exposure to vibrations over long term, and hence, the methods defined in the European directive may be limited in their ability to ensure the safety of workers exposed to WBV throughout their years of employment. Method: A detailed comparison and discussion of methods defined in the European Directive and the ISO2631-5:2018 was used as a starting point of the main results of this paper. On this basis, a new methodology for the management and organization of preventive measures is proposed to consider the assessment of ISO2631-5:2018 standard and the full working life of workers. Experimental data to assess exposure to WBV in heavy equipment vehicle (HEV) drivers under different road surface conditions and range of velocities were considered to illustrate the process of the proposed methodology. Results: The methods defined in the standards provide different assessments leading to a different possible consideration of safe operations when the risks associated with them may actually be high. The proposed methodology can be used with the aim of ensuring safety of workers throughout their working lives and providing an easy implementation of the calculations of ISO2631-5:2018 standard. Conclusions: A procedure to assess the health risk probability to which the HEV worker is exposed in terms of the exposure years and a different range of operational vehicle speeds is proposed and exemplified with a study case. Practical applications: This study provides a practical tool for the management of WBV exposure related to work-tasks in HEV drivers. Safety managers should consider the global exposition to WBV throughout their working life, and this research provides an easy tool to accomplish it.

Prediction of the influence of vertical whole-body vibration on biomechanics of spinal segments after lumbar interbody fusion surgery

BackgroundPrevious studies have shown that for healthy spine, cyclic loading encountered due to whole-body vibration exposure generated higher responses in spinal tissues than static loading. However, how whole-body vibration affects spine biomechanics after interbody fusion surgery is poorly understood. This study aimed at comparing the effects of vibration loading on spinal segments between postsurgical and healthy lumbar spines. MethodsA validated finite element model of healthy human lumbosacral spine was modified to simulate interbody fusion at L4–L5 level considering the statuses immediately after surgery (before bony fusion) and after bony fusion. Biomechanical responses at its adjacent levels for the healthy and fusion models to a sinusoidal axial vibration load of ±40 N and the corresponding static axal loads (−40 N and 40 N) were computed using transient dynamic and static analyses, respectively. FindingsFor both healthy and fusion models, vibration amplitudes of the predicted responses were significantly higher than the corresponding changing amplitudes under static loads. Specifically, the increasing effect of vibration load in disc bulge, disc stress and intradiscal pressure at L3–L4 level reached 255.9%, 215.0% and 224.4% for the healthy model, 157.4%, 177.8% and 171.8% for the fusion model (before bony fusion), 141.9%, 152.6% and 160.1% for the fusion model (after bony fusion). InterpretationAlthough whole-body vibration is still more dangerous for the lumbar spine after interbody fusion surgery than static loading, the sensitivity of adjacent segment in postsurgical spine to vibration loading is decreased compared with healthy spine, especially when reaching to bony fusion.

Relationship between occupational exposure to whole-body vibration and noise with sex hormone levels: An empirical assessment in an automobile parts manufacturing plant.

The present study investigated the relationship between occupational exposure to noise and whole-body vibration (WBV) with the levels of sex hormones in an automobile parts manufacturing plant. The level of workers' exposure (n = 162) to each of the mentioned stressors was measured through standard methods, and the time-weighted average of exposure was calculated for each person. In order to determine serum sex hormones (free testosterone, luteinizing hormone, and follicle-stimulating hormone), blood samples were taken from all participants after 8-10 h of fasting between 7 and 9 am and then the blood samples were analyzed by an enzyme-linked immunosorbent assay method. In general, regarding testosterone as the main male sex hormone, only 49% of the participants were in the normal range. In a total of three sections, the lowest mean testosterone levels were observed in the third exposure group (WBV > 1.93 m/s2; noise >92.69 dB) of the studied stressor; however, only the difference in testosterone levels between the three different groups of exposure to noise was statistically significant (p = 0.001). The relationship between demographic variables and levels of noise and WBV exposure with sex hormones was not linear and only the relationship between noise exposure and testosterone levels was statistically significant (R = -0.201, p = 0.013). According to the results of logistic regression, the WBV had the greatest effect on testosterone levels. However, according to the results of the correlation test, only the relationship between noise exposure and testosterone levels was statistically significant.

Truck loading or unloading operations: Reduction of the whole-body vibration exposure of pallet truck drivers at the dock leveller location

In France, 10% of workers are exposed to whole-body vibration that can affect their health. Operators of stand-on electric pallet trucks are subjected to severe vibration on their suspended platform. Measurements in companies have shown that coming in and out of a semi-trailer when crossing a dock leveller are the most critical operations in terms of shocks and vibration. This is mainly due to floor irregularities at the loading dock area. Moreover, no standardized test code exists to assess the irregularity roughness either at the dock leveller design stage or when installed in a company. This study had dual objectives. The first was to reduce the whole-body vibration exposure of workers during truck loading or unloading. The second objective was to develop a test protocol to assess the unevenness/roughness encountered along the route, mostly around the loading dock area. In partnership with a logistics company, the operator’s activity and different loading dock areas were studied and the daily vibration exposure of drivers was calculated. Consequently, the driving habits of the drivers were changed, the surface state and uses of dock levellers were modified and the irregularities encountered, mainly at the boundary between the dock leveller and semitrailer, were treated. The reducing of daily vibration exposure by between 30% and 50% was possible with simple solutions.

The influence of combined exposure to noise and whole-body vibration on hearing loss under simulated heavy equipment driving conditions

Noise-induced hearing loss (NIHL) is a serious problem in occupational environments; however, there is little information about hearing loss due to combined exposure to noise and vibration. This study aimed to investigate the combined effects of exposure to noise and whole-body vibration (WBV) on hearing responses under simulated heavy equipment driving conditions. A repeated measures study was designed to evaluate the changes in distortion product otoacoustic emissions (DPOAE) amplitudes as hearing responses to 40 min of noise and/or WBV exposure. Thirty healthy males with an average age of 30.17 (±3.94) years, exposed to noise level of 85 dB(A) and two WBV levels (0.87 and 1.3 m/s2) in six experimental scenarios. The findings revealed that there was a significant change in DPOAE amplitudes after single noise exposure and combined noise and WBV exposure (p < 0.05); however, there was no significant difference in WBV exposure alone (p > 0.05). The changes in DPOAE amplitudes were greater in combined exposure to noise and WBV (1.3 m/s2) in all sessions. The statistical analysis showed the effect sizes of the combined exposure to noise and WBV were more than the sum of the exposure to each one alone. It can be concluded that some synergic effects can occur in DPOAE amplitudes in the combined noise and WBV exposure under heavy equipment driving conditions. These findings can help the occupational health experts adapt the existing physical agents' exposure limits to the realistic conditions of the occupational settings.

Predictors of Whole-Body Vibration Exposure among Indian Bus and Truck Drivers

Heavy vehicle drivers in the Indian road transport industry are generally exposed to whole-body vibration (WBV) and shock loading resulting in musculoskeletal disorders (MSDs) in their different body parts. Not much work has been done in identifying the contribution of driver’s personal and vehicle/road-related factors in the enhancement of vibration and shock exposure. This study has been conducted on 10 bus and 10 truck drivers from Northern India to investigate the role of these factors. Based on previous studies, the factors or predictor variables included were driver’s age, body mass index (BMI), driving experience, age of vehicle, mileage, age of tyres, and seat pad thickness. 8-hours vector sum acceleration, i.e., (A(8)s) and vibration dose value, i.e., ( VDV(8)s) of 25% of the drivers were found to be more than upper limit values of ISO 2631-1. The WBV exposure magnitudes of acceleration and vibration dose value were much higher along the vertical z-axis than along the longitudinal x-axis and lateral y-axis. The results of univariate linear regression analysis found both vibrations and shocks to be related to the driver’s age, body mass index (BMI), driving experience, vehicle speed, and road roughness. Similar types of results were observed from multiple regression analyses with the only exception that no association was found between BMI and WBV exposure in this case. The results of the study may help the authorities in minimising the risks associated with the driver’s profession.

Deleterious effects of whole-body vibration on the spine: A review of in vivo, ex vivo, and in vitro models.

Occupational exposure to whole‐body vibration is associated with the development of musculoskeletal, neurological, and other ailments. Low back pain and other spine disorders are prevalent among those exposed to whole‐body vibration in occupational and military settings. Although standards for limiting exposure to whole‐body vibration have been in place for decades, there is a lack of understanding of whole‐body vibration‐associated risks among safety and healthcare professionals. Consequently, disorders associated with whole‐body vibration exposure remain prevalent in the workforce and military. The relationship between whole‐body vibration and low back pain in humans has been established largely through cohort studies, for which vibration inputs that lead to symptoms are rarely, if ever, quantified. This gap in knowledge highlights the need for the development of relevant in vivo, ex vivo, and in vitro models to study such pathologies. The parameters of vibrational stimuli (eg, frequency and direction) play critical roles in such pathologies, but the specific cause‐and‐effect relationships between whole‐body vibration and spinal pathologies remain mostly unknown. This paper provides a summary of whole‐body vibration parameters; reviews in vivo, ex vivo, and in vitro models for spinal pathologies resulting from whole‐body vibration; and offers suggestions to address the gaps in translating injury biomechanics data to inform clinical practice.

Effects of whole body vibration and backrest angle on perceived mental workload and performance.

Mental Workload (MWL) and human performance are widely contributing concepts in human factors. The objective of the current study is to investigate the perceived MWL and human performance during whole-body vibration (WBV) exposure while seated at different backrest angles. Nineteen healthy male participants completed both the NASA-TLX and rating scale mental effort (RSME) after performing two difficulty levels of computerized dual tasks. The participants' performance was measured in these conditions while seated with a backrest angle of 100 and 120 degrees and exposed to WBV (intensity: 0.5 m/s2; frequency 3-20 Hz) for 5 minutes. No significant effect on performance or perceived MWL (p<0.05) was found when changes were made to the backrest angles. Exposure to WBV under two backrest angles increased mental demand (p=0.04), effort (p=0.03) and frustration (p=0.03) and negatively affected human performance (p<0.05). The present study showed that exposure to WBV could be an important variable for designing work environments that require a high level of performance and mental demand while seated. However, the findings exhibited no association between inclining backrest angle and human performance or perceived MWL.

The effects of different seat suspension types on occupants' physiologic responses and task performance: implications for autonomous and conventional vehicles

This study evaluated whole body vibration (WBV), non-driving task performance, muscle activity, and self-reported discomfort and motion sickness between different seat suspension systems in a simulated vehicle environment. In a repeated-measures laboratory experiment where field-measured 6-degree-of-freedom (6-DOF) passenger vehicle vibration was replicated on a 6-DOF motion platform, we measured WBV, non-driving task (pointing, typing, web-browsing, and reading) performance, low back (erector spinae), shoulders (trapezius) and neck (splenius capitis and sternocleido-mastoid) muscle activity, and self-reported discomfort and motion sickness from three different seats: a vertical (z-axis) active suspension, multi-axial active suspension [vertical (z-axis) + lateral (y-axis)], and a static suspension-less seat (current seat type in all passenger cars). Both the vertical and multi-axial active suspension seats significantly reduced the vertical WBV exposure (p < 0.0001). However, no significant differences were found in non-driving task performance (p > 0.30), muscle activity (p > 0.22), self-reported discomfort (p > 0.07), and motion sickness (p = 0.53) across three different seats. These findings indicate that the active suspension seats may have potential to future reduce the vertical and total WBV exposures, respectively. However, none of the suspension seats demonstrate any significant benefits on the non-driving task performance, muscle activity, self-reported discomfort and motion sickness measures in a simulated vehicle environment.

Managing Vibration Training Safety by Using Knee Flexion Angle and Rating Perceived Exertion

Whole-body vibration (WBV) is commonly applied in exercise and rehabilitation and its safety issues have been a major concern. Vibration measured using accelerometers can be used to further analyze the vibration transmissibility. Optimal bending angles and rating of perceived exertion (RPE) evaluations have not been sufficiently explored to mitigate the adverse effect. Therefore, the aims of this study were to investigate the effect of various knee flexion angles on the transmissibility to the head and knee, the RPE during WBV exposure, and the link between the transmissibility to the head and the RPE. Sixteen participants randomly performed static squats with knee flexion angles of 90, 110, 130, and 150 degrees on a WBV platform. Three accelerometers were fixed on the head, knee, and center of the vibration platform to provide data of platform-to-head and platform-to-knee transmissibilities. The results showed that the flexion angle of 110 degrees induced the lowest platform-to-head transmissibility and the lowest RPE (p < 0.01). A positive correlation between RPE and the platform-to-head transmissibility was observed. This study concluded that a knee flexion of about 110 degrees is most appropriate for reducing vibration transmissibility. The reported RPE could be used to reflect the vibration impact to the head.

Assessment of ergonomic risk factors in occupational motorcycle riding: an experimental investigation

Today, the use of motorcycles has increased in the e-commerce sector for the delivery of fast food, courier or parcels, etc. The associated risk of discomfort exists here, due to long hours of exposure. For the ergonomic risk factors assessment, an experimental simulation of motorcycle riding from an occupational point of view was planned. In this, participants were invited to ride the motorcycle for 25 min at an average speed of 30 km/h for different riding postures depending on the geometry of the motorcycles. Whole body vibration (WBV) has been shown to be a major ergonomic risk factor as per the ISO 2631-1 assessment. The WBV exposure level found to be exceeding the upper limit of the health guideline caution zone (HGCZ) of ISO 2631-1 by more than five times. WBV exposure was higher for the slightly forward lean riding posture motorcycle than for the upright erect riding posture motorcycle. In addition, upper body muscle activities have shown that the slightly forward lean posture had higher muscular activity than the upright erect posture. Ergonomic interventions can reduce the risk of work-related musculoskeletal disorders (WMSDs) to delivery workers if implemented.

Phase-based evaluation of whole-body vibration exposure for hydraulic excavator operators

Phase-based evaluation of whole-body vibration exposure for hydraulic excavator operators

Exposure of agricultural pilots to occupational whole-body vibration: The effects of runway maintenance and the stages of flight

BackgroundAgricultural pilots fly inside rural areas, usually, in runways without proper maintenance. Neglected runway maintenance contributes to increased exposure to shocks and vibrations. On the other hand, during cruise and spraying, the pilot is not exposed to the effect of the runway surface, and thus the exposure may be different. ObjectiveThe aim of this study is to investigate the factors that may increase occupational exposure to WBV in agricultural pilots. MethodThe methodology used in this study consisted of evaluating the exposure of WBV according to the runway surface quality and the stages of flight for a sample of four different agricultural aircraft models. ResultsThe results confirmed that the magnitude of the vibration is significantly influenced by the runways surface quality and the stages of flight. This suggests the possibility to decrease the exposure to WBV improving runway maintenance and managing flight time. Relevance for the industryBased on the results of the present study, it was possible to define strategies to reduce whole-body vibration exposure and thus improve the working conditions of agricultural pilots.

Postural balance effects from exposure to multi-axial whole-body vibration in mining vehicle operation

Twenty participants (18 males and 2 females) completed postural stability assessments before and after 4-h exposure to whole body vibration (WBV) in four experimental conditions: (a) vertical-dominant WBV with vertical passive air suspension, (b) multi-axial WBV with vertical passive air suspension, (c) multi-axial WBV with multi-axial active suspension, and (d) no WBV condition. Center of pressure (COP)-based postural sway measures significantly increased following multi-axial WBV exposure. Increase in COP velocity and displacement following multi-axial WBV was significantly higher than the increase in all the other exposure conditions. However, no significant differences between the WBV conditions were observed in functional limits of stability and anticipatory postural adjustments. While our results show standing balance to be impaired following the multi-axial WBV exposure of off-road mining vehicles, dynamic stability across a broader range of conditions needs to be understood to causally link postural stability decrements to increased fall-risks associated with off-road vehicle operators.

Occupational exposure of dumper operators to whole-body vibration in opencast coal mines: an approach for risk assessment using a Bayesian network

Whole-body vibration (WBV) is one of the leading risk factors for development of musculoskeletal disorders (MSDs) that develop symptoms of lower back pain, pain in the neck and shoulders, digestive problems, blood pressure and diabetes among professional dumper operators. The present study specifically aimed at assessing the WBV exposure of 79 dumper operators engaged in two Indian opencast coal mines through vibration measurements followed by questionnaire survey. From the daily frequency-weighted root mean square exposure, dumper operators have experienced vibration levels higher than the Health Guidance Caution Zone (HGCZ) of Standard No. ISO 2631-1:1997. However, on the basis of daily vibration dose values, 60.8% of operators have experienced vibration levels above the HGCZ. Finally, an attempt was also made to explore the potential of a Bayesian network to predict the risk factors for WBV of dumper operators in development of MSDs to prioritize the factors for human health risk assessment.

An investigation on major physical hazard exposures and health effects of forestry vehicle operators performing wood logging processes

Forest vehicle operators are occupationally exposed to combined hazards such as noise, whole-body vibration(WBV), adverse microclimate, and carbon monoxide. Such combined exposures may not only increase the risk of accidents but they may also have some synergized effects on the developments of major occupational diseases of the workers, which have been among the major concerns of the occupational safety and health for the forestry sector in Romania. This study investigated the combined exposures through measuring and analyzing the equivalent acoustic level LAeq (dB(A)), whole-body vibration (A(8)-value), working microclimate, and carbon monoxide inside the worker's cabin in the breathable area. The vehicles considered in this study included skidding vehicles dedicated to wood exploitation (type I) and agricultural tractors modified for logging (type II). The cumulative distribution function of each types of exposure was calculated in the analyses. This study found that the noise and WBV exposures had large probabilities of exceeding the permissible limits: for noise, 75% for vehicle type I, and 55% for vehicle type II; for the WBV, 63% for type I vehicles, and 72% for type II vehicles. The measured data suggest that the microclimate and carbon monoxide exposures were within their limits in the process of collecting wood. This study also found that 27% of workers participated in the study were detected with occupational diseases. Based on these findings, some intervention methods were recommended to control the exposures and health effects.

Vibration transmissibility and apparent mass changes from vertical whole-body vibration exposure during stationary and propelled walking

Whole-Body Vibration (WBV) is an occupational hazard affecting employees working with transportation, construction or heavy machinery. To minimize vibration-induced pathologies, ISO identified WBV exposure limits based on vibration transmissibility and apparent mass studies. The ISO guidelines do not account for variations in posture or movement. In our study, we measured the transmissibility and apparent mass at the mouth, lower back, and leg of participants during stationary and propelled walking. Stationary walking transmissibility was significantly higher at the lumbar spine and bite bar at 5 and 10 Hz compared to all higher frequencies while the distal tibia was lower at 5 Hz compared to 10 and 15 Hz. Propelled walking transmissibility was significantly higher at the bite bar and knee at 2 Hz than all higher frequencies. These results vary from previously published transmissibility values for static participants, showing that ISO standards should be adjusted for active workers.

Immediate effects of whole-body vibration exposure on perceived exertion and peripheral hemodynamics in overweight and obese individuals

ABSTRACT Objective The study aim was to investigate the immediate effects of whole-body vibration (WBV) exposure in combination with physical exercises on perceived exertion and peripheral hemodynamic responses in overweight and obese individuals. Methods Thirty-six individuals who were overweight or obese (44% males, mean age = 44.17 (9.43) years, mean BMI = 33.29 (3.19) kg/m2) were recruited. Participants were randomly allocated to two groups: control (n = 17) and the WBV (n = 19) group with vibration at 30 Hz and amplitude of 2 mm for a 20-min single vibration session. All participants completed static and dynamic exercises on the sinusoidal-vertical vibration plate but without vibration exposure in the control group. The Borg Rating of Perceived Exertion Scale (RPE) was used to evaluate perceived exertion. Hemodynamic responses were measured with heart rate (HR), arterial blood pressure (aBP) and peripheral capillary oxygen saturation (SpO2) in the pre-WBV, post-WBV, and the recovery period. Results A prolonged increase in perceived exertion was observed in the WBV group (ES = 0.48, p = 0.025), as compared to the control group (ES = 0.10, p = 0.668) in the recovery period. However, the Borg RPE between-groups comparison showed no significant differences in the pre-WBV, post-WBV, and recovery periods. No significant differences in group-time interaction were found for HR, aBP, and SpO2 hemodynamics. Conclusions WBV exposure had no significant positive effect on perceived exertion and hemodynamic responses in overweight and obese individuals.