Whole-body Vibration Exposure Research Articles

Reducing musculoskeletal disorders in iron ore mine operators: A fuzzy-based intervention approach.

This study focuses on evaluating the exposure to whole-body vibration (WBV) and association of musculoskeletal disorders (MSDs) with various risk factors among dumper operators in the mining industry. Despite the issue's significance, prior research has been limited. The study introduces a novel fuzzy-based approach for identifying, selecting, and prioritizing safety measures to mitigate MSD risks. Data collection comprised face-to-face interviews, anthropometric measurements, Rapid Upper Limb Assessment (RULA) scoring for posture assessment, and the Nordic Musculoskeletal questionnaire for assessment of MSD prevalence. Multiple linear and logistic regression models were used to analyse the contributing risk factors to MSDs and WBV exposure. These risk factors formed the basis for a practical approach to select appropriate safety measures based on fuzzy based aggregation method of expert's judgment aimed at mitigating the risk of MSDs. The results revealed that the risk factors such as poor work posture, WBV exposure and poor seat design were significantly associated with neck (adjusted odds ratio aOR = 4.81), upper limb and shoulder (aOR = 3.28), upper back (aOR = 5.09), and lower back pain (aOR = 3.67) at p < 0.05. Using these factors to formulate safety measures to reduce MSD risk, the minimization of sharp turns and abrupt changes in elevation in designing the haul roads, scheduled maintenance practices, and ergonomic seat design were found as important safety measures in this study. Our unique methodological approach in occupational health research could be highly beneficial for tailoring safety measures at the unit level with minimal effort.

The Development of a High-Static Low-Dynamic Cushion for a Seat Containing Large Amounts of Friction

Exposure to whole-body vibration (WBV) has been shown to result in lower-back pain, sciatica, and other forms of discomfort for operators of heavy equipment. While WBV is defined to be between 0.5 and 80 Hz, humans are most sensitive to vertical vibrations between 5 and 10 Hz. To reduce WBV exposure, a novel seat cushion is proposed that optimally tunes a High-Static Low-Dynamic (HSLD) stiffness isolator. Experimental and numerical results indicate that the cushion can drastically increase the size of the attenuation region compared to a stock foam cushion. When placed on top of a universal tractor seat, the cushion is capable of mitigating vibrations at frequencies higher than 1.1 Hz. For comparison, the universal tractor seat with a stock foam cushion isolates vibrations between 3.4 and 4.1 Hz, as well as frequencies larger than 4.8 Hz. Friction within the universal seat is accurately modeled using the Force Balance Friction Model (FBFM), and an analysis is conducted to show why friction hinders overall seat performance. Finally, the cushion is shown to be robust against changes in mass, assuming accurate tuning of the preload is possible.

Effects of Whole-Body Vibration Combined with Blood Flow Restriction and Systemic Hypoxia on Body Composition and Physical Performance in Overweight University Students

Study purpose. This study investigated the effects of whole-body vibration (WBV) combined with blood flow restriction (BFR) and hypoxic exposure (HYP) on body composition and physical performance in overweight university students. Materials and methods. Twenty-nine male university students with overweight were divided into 3 groups: 1) whole-body vibration (WBV), 2) whole-body vibration plus blood flow restriction (WBV+BFR, 60% of occlusion pressure) and 3) whole-body vibration plus hypoxic exposure (WBV+HYP, FiO₂ = 15.8%). Training included 10 sets of intermittent WBV exercise (30-35 Hz in frequency and high amplitude) 20 min/day and 3 days/week. Body composition along with physical performance was measured before (2-3 days prior) and after (2-3 days post) an 8-week training period. Results. The results of this study were as followed, after training, the maximum strength (1RM) in the leg press and leg curl were significantly increased in the WBV+HYP group (28.31%, p = 0.016 and 13.56%, p = 0.017) compared with the WBV group (17.68% and 2.88) respectively. Similarly, the WBV+HYP group showed a substantial increase in muscle endurance in the leg extension and leg curl (28.57%, p = 0.013 and 34.38% p = 0.049) when compared to the WBV group (5.33% and 13.20%) respectively. Conclusions. Whole-body vibration combined with blood flow restriction and hypoxic exposure were effective in improving body composition and physical fitness. Performing the procedure can also be adjusted according to convenience and suitability for each individual. It is a guideline for preventing, treating, and promoting health among overweight adolescents.

Sensorimotor integration is affected by acute whole-body vibration: a coherence study.

Introduction: Several whole-body vibration (WBV) effects on performance have been related to potential changes in the neural drive, motor unit firing rate, and sensorimotor integration. In the present paper, motor unit coherence analysis was performed to detect the source of neural modulation based on the frequency domain. Methods: Thirteen men [25 ± 2.1years; Body Mass Index (BMI) = 23.9 ± 1.3kgm2; maximal voluntary force (MVF): 324.36 ± 41.26N] performed sustained contractions of the Tibialis Anterior (TA) at 10%MVF before and after acute WBV. The vibrating stimulus was applied barefoot through a platform to target the TA. High-Density surface Electromyography (HDsEMG) was used to record the myoelectrical activity of TA to evaluate coherence from motor unit cumulative spike-trains (CSTs). Results: Mean coherence showed a significant decrease in the alpha and low-beta bandwidths (alpha: from 0.143 ± 0.129 to 0.132 ± 0.129, p = 0.035; low-beta: from 0.117 ± 0.039 to 0.086 ± 0.03, p = 0.0001), whereas no significant changes were found in the other ones (p > 0.05). The discharge rate (DR) and the Force Covariance (CovF%) were not significantly affected by acute WBV exposure (p > 0.05). Discussion: According to the significant effects found in alpha and low-beta bandwidths, which reflect sensorimotor integration parameters, accompanied by no differences in the DR and CovF%, the present results underlined that possible neural mechanisms at the base of the previously reported performance enhancements following acute WBV are likely based on sensorimotor integration rather than direct neural drive modulation.

Effects of Vertical-Axial Dominant and Multi-Axial Vibration on Postural Stability

This repeated-measures laboratory study characterized the relative impacts of vertical-axial dominant and multi-axial Whole-Body Vibration (WBV) exposures on postural stability. Eleven healthy participants were exposed to field-measured vibration profiles collected from on-road commercial (vertical-dominant WBV) and off-road mining vehicles (multi-axial WBV) for four hours on two different days. Before and after the exposure, postural stability was evaluated while participants performed sit-to-stand tasks followed by static standing tasks. Overall, the study results indicate that off-road, multi-axial WBV may compromise postural stability more so than on-road, vertical-dominant WBV. These findings may suggest that off-road vehicle operators are at a greater risk of fall-related injuries. Therefore, there is a critical need to develop more effective vibration control measures among off-road vehicle operators.

The effect of selected rest break activities on reaction time, balance, and perceived discomfort after one hour of simulated occupational whole-body vibration exposure in healthy adults

Background & Objective : Negative health effects from occupational whole-body vibration (WBV) exposure during machinery operation include alterations in proprioception, vestibular function, reaction time, stress, motor response, and decrements in musculoskeletal health. To reduce WBV exposure during machinery operation, it may be possible to incorporate short rest break activities throughout the day. This study aims to determine if there are intervention activities that can minimize decrements in cognitive, proprioceptive, and musculoskeletal effects related to WBV exposure during machine operation. Materials & Methods Eleven healthy adults participated in four 1-hour sessions of ecologically valid WBV exposure followed by one of four 5-minute activities: sitting, walking, 2 min of gaze stabilization exercise (GSE) coupled with 3 min of trunk mobility exercise (GSE + MOBIL), or 2 min of GSE coupled with a 3-minute walk (GSE + WALK). Baseline and post-activity measurements (rating of perceived discomfort, balance and postural sway measurements, 5-minute psychomotor vigilance task test) were submitted to a paired t-test to determine the effect of WBV exposure and activities on physical, cognitive, and sensorimotor systems and to a repeated measures ANOVA to determine any differences across activities. Results We observed degradation of the slowest 10% reaction speed outcomes between baseline and post-activity after walking (7.3%, p < 0.05) and sitting (8.6%, p < 0.05) but not after GSE + MOBIL or GSE + WALK activities. Slowest 10% reaction speed after GSE + MOBIL activity was faster than all other activities. The rating of perceived discomfort was higher after SIT and WALK activities. There were no notable differences in balance outcomes. Conclusion When compared to sitting for 5 min, an activity including GSE and an active component, such as walking or trunk mobility exercises, resulted in maintenance of reaction time after WBV exposure. If confirmed in occupational environments, GSE may provide a simple, rapid, effective, and inexpensive means to protect against decrements in reaction time after WBV exposure.

Role of contributing factors on health risks of whole-body vibration exposure of heavy equipment and vehicle operators: A critical review

Whole-body vibration (WBV) is a recognized health hazard that primarily affects the musculoskeletal system of human beings. Although research works on WBV are documented, for the past few decades or so, researchers are still attempting to explore the role of contributing factors of WBV for the causation of musculoskeletal disorders (MSDs). Therefore, this paper synthesizes up-to-date knowledge on WBV with respect to measurement methods, critical vibration magnitudes, contributing factors, and effects on human health. The present review is based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyzes) that includes 112 studies on WBV exposure and its contributing factors. It also summarizes the contributing factors of MSDs that include personal factors, environmental factors, machine-related factors, and WBV exposure of the heavy vehicles and equipment operators across various industries. Most of the studies reported lower back pain as the most common MSDs experienced by the vehicle operators exposed to WBV, followed by upper back pain. However, it is apparent from the prevailing literature that musculoskeletal health risks do not result from exposure to WBV alone. The role of multivariate contributing factors should also be considered, analyzed, assessed, and understood to establish correlations between these factors with the development of MSDs. In addition to the measurement and assessment of WBV as per the ISO guidelines to evaluate the potential and likely health risks faced by the heavy equipment operators, researchers should also focus on studying various impacts of WBV, and understanding the role of its contributing factors on human health using advanced machine learning tools.

Occupational exposure to whole-body vibration and neck pain in the Swedish general population

The primary aim of this study was to determine if occupational exposure to whole-body vibration (WBV) was associated with reporting neck pain. A cross-sectional study was conducted on a sample of the general population living in northern Sweden, aged 24–76 years. Data was retrieved through a digital survey that collected subjectively reported information on exposure to WBV and biomechanical exposures as well as neck pain. The study included 5,017 participants (response rate 44%). Neck pain was reported by 269 men (11.8%) and 536 women (20.2%). There was a statistically significant association between reporting occupational exposure to WBV half the time or more (adjusted OR 1.91; 95% CI 1.22–3.00) and reporting neck pain. In gender-stratified analyses, the same pattern was observed in men, while there were too few women to determine any association. We conclude that occupational exposure to whole-body vibration was associated with neck pain in men. Practitioner summary: This cross-sectional, survey-based study investigated associations between self-reported occupational whole-body vibration and neck pain. It showed significant associations between frequent exposure to whole-body vibration and neck pain among men but not women. In occupational health care settings, whole-body vibration could be considered as a possible risk factor for neck pain.

Effect of Whole-Body Vibration Exposure in Vehicles on Static Standing Balance after Riding

This study aims to investigate the effects of whole-body vibration (WBV) exposure on the disturbance of standing balance function assuming that the cause of slip, trip and fall accidents in the land transportation industry is related to WBV exposure when traveling in vehicles. In the experiment, ten participants underwent 60 min of virtual driving in a driving simulator (DS) for WBV exposure. In addition, standing balance measurements were conducted before exposure, immediately after exposure, 2 min after exposure and 4 min after exposure. Four conditions were considered by combining two magnitudes of WBV exposure and the driver and passenger conditions. This study focused on two indexes of standing balance, namely, total length and enveloped area and the rate of change relative to the value before the vibration exposure was calculated. The rate of change remained almost constant at 1.0 in the control condition without vibration exposure, whereas that under vibration exposure conditions varied. Interestingly, the rate of change at 2 min after exposure remained high in the driver condition, but it decreased to almost 1.0 in the passenger condition. Since no difference appeared in the vibration acceleration measured at the seating surface between the driver and passenger conditions, it was believed that the difference between the driving and passenger conditions was related to fatigue caused by the accelerator-pedal operation. As a result of considering the percentage of the standing balance that returned to 1.0 after 4 min in most conditions, this study proposed that a rest period of several minutes be allowed from the experiment in which the participants were exposed to vibration at 0.5m/s2 rms for 60 min at the DS. Further basic experiments will be conducted to introduce another WBV exposure assessment, including loss of standing balance as a health indicator, to ISO 2631-1.

Proposal for a Low-Cost Monitoring System to Assess the Pavement Deterioration in Urban Roads

Effective scheduling of pavement monitoring and maintenance activities plays a pivotal role in ensuring safety and comfort for road users. The Pavement Management System (PMS) is a traditional tool to assist the road manager in the decision-making process on which priority maintenance activities to carry out. However, for urban road networks the implementation of a PMS can be complicated due to the many functional and operational problems. This paper presents a prototype low-cost inertial sensor-based system for monitoring the pavement conditions in urban road networks. Starting by the measurements of the vertical accelerations collected in a vehicle riding on a rough pavement, the frequency-weighted vertical acceleration a_wz was calculated according to ISO 2631 standard. This parameter can be adopted as a Key Performance Indicator (KPI) by relating the road roughness to the human whole-body vibration (WBV) exposure on the road user. Some field tests were carried out identifying urban roads in an Italian city with different levels of pavement deterioration. Measurements to evaluate the pavement deterioration were performed using traditional visual inspections and the proposed sensor embedded in a test vehicle (run at different speeds) in order to identify a relationship between these indices in terms of performance classes.

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

ABSTRACT 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.

An investigation of the Wenda GI.34 bus driver seat based on the whole-body vibration exposure level

An investigation of the Wenda GI.34 bus driver seat based on the whole-body vibration exposure level

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

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

Increase in serum nerve growth factor but not intervertebral disc degeneration following whole-body vibration in rats

BackgroundLow back pain is a leading cause of disability and is frequently associated with whole-body vibration exposure in industrial workers and military personnel. While the pathophysiological mechanisms by which whole-body vibration causes low back pain have been studied in vivo, there is little data to inform low back pain diagnosis. Using a rat model of repetitive whole-body vibration followed by recovery, our objective was to determine the effects of vibration frequency on hind paw withdrawal threshold, circulating nerve growth factor concentration, and intervertebral disc degeneration. MethodsMale Sprague-Dawley rats were vibrated for 30 min at an 8 Hz or 11 Hz frequency every other day for two weeks and then recovered (no vibration) for one week. Von Frey was used to determine hind paw mechanical sensitivity every two days. Serum nerve growth factor concentration was determined every four days. At the three-week endpoint, intervertebral discs were graded histologically for degeneration. FindingsThe nerve growth factor concentration increased threefold in the 8 Hz group and twofold in the 11 Hz group. The nerve growth factor concentration did not return to baseline by the end of the one-week recovery period for the 8 Hz group. Nerve growth factor serum concentration did not coincide with intervertebral disc degeneration, as no differences in degeneration were observed among groups. Mechanical sensitivity generally decreased over time for all groups, suggesting a habituation (desensitization) effect. InterpretationThis study demonstrates the potential of nerve growth factor as a diagnostic biomarker for low back pain due to whole-body vibration.

Effects of whole-body vibration on reproductive physiology in a rat model of whole-body vibration

ABSTRACT Findings from epidemiological studies suggest that occupational exposure to whole-body vibration (WBV) may increase the risk of miscarriage and contribute to a reduction in fertility rates in both men and women. However, workers exposed to WBV may also be exposed to other risk factors that contribute to reproductive dysfunction. The goal of this experiment was to examine the effects of WBV on reproductive physiology in a rat model. Male and female rats were exposed to WBV at the resonant frequency of the torso (31.5 Hz, 0.3 g amplitude) for 4 hr/day for 10 days. WBV exposure resulted in a significant reduction in number of developing follicles, and decrease in circulating estradiol concentrations, ovarian luteinizing hormone receptor protein levels, and marked changes in transcript levels for several factors involved in follicular development, cell cycle, and steroidogenesis. In males, WBV resulted in a significant reduction in spermatids and circulating prolactin levels, elevation in number of males having higher circulating testosterone concentrations, and marked alterations in levels of transcripts associated with oxidative stress, inflammation, and factors involved in regulating the cell cycle. Based upon these findings data indicate that occupational exposure to WBV contributes to adverse alterations in reproductive physiology in both genders that may lead to reduction in fertility.

Body physiological responses of city bus drivers subjected to noise and vibration exposure in working environment

BackgroundThe city bus drivers have critical roles in public transport and are occupationally exposed to different environmental stressors. This study aimed to investigate body physiological responses of city bus drivers subjected to noise and vibration exposure while crossing city routes. MethodsThis cross-sectional study was conducted on 103 city bus drivers working in the governmental transportation system in Hamadan city. The subjects' exposures to noise and body vibration were measured during driving activities. Their blood pressure (BP), as well as heart rate (HR), were measured before and after driving. Multivariate regressions (MLR) were employed to analyze the effect size of the stimulus on body physiological responses using SPSS 22. ResultsExposure levels to noise, whole-body vibration (WBV), and hand-arm vibration among drivers were 79.50 ± 3.51dB, 0.620 ± 0.159 m/s2, and 0.438 ± 0.064 m/s2, respectively which were lower than the exposure limits. Heart rate as main physiological response before and after driving were 74.22 ± 4.11 and 79.23 ± 8.59 bpm, respectively. The developed MLR models statistically showed that noise exposure could only affect the HR (β = 0.193 and p < 0.001); while WBV exposure affected both BP (β = 0.360 and p < 0.001) and HR (β = 0.367 and p = 0.020). The statistical analysis represented that exposure to noise and vibration in the presence of other possible covariates have significant effects on body physiological responses. ConclusionThe study empirically confirmed the possibility of body physiological changes influenced by physical stimulus during real driving activities. It is highly recommended that occupational health surveillance should continuously be implemented to maintain and promote the safety and health of drivers throughout their careers.

Modal Characterization of Manual Wheelchairs

Manual wheelchair (MWC) users are exposed to whole-body vibrations (WBVs) during propulsion. Vibrations enter the MWC structure through the wheels’ hub, propagate according to the MWC dynamical response, and finally reach the user’s body by the footrest, seat, backrest, and handrims. Such exposure is likely to be detrimental to the user’s health and a source of discomfort and fatigue which could, in daily life, impact users’ social participation and performance in sports. To reduce WBV exposure, a solution relies on MWC dynamical response modelling and simulation, where the model could indeed be used to identify parameters that improve the MWC dynamic. As a result, it is necessary to first assess the MWC dynamical response. In this approach, experimental modal analyses were conducted on eleven MWCs, including daily and sport MWCs (tennis, basketball, and racing). Through this procedure, modal properties (i.e., modal frequencies, damping parameters, and modal shapes) were identified for each MWC part. The results pointed out that each MWC investigated, even within the same group, revealed specific vibration properties, underlining the difficulty of developing a single vibration-reducing system for all MWCs. Nevertheless, several common dynamical properties related to MWC comfort and design were identified.

The association between whole body vibration exposure and spine degeneration on imaging: A systematic review.

Low frequency vibrations from motorized vehicles and heavy equipment have been associated with musculoskeletal disorders. Spine degeneration on diagnostic imaging provides direct and objective measures of the possible effects of such exposures on the spine. The objective of this systematic review was to evaluate the association of exposure to whole-body vibration (WBV) with spine degeneration on imaging. We conducted electronic searches in MEDLINE, CINAHL, EMBASE, and Web of Science to July 2021. Two reviewers independently screened search results, assessed quality, and extracted data. Studies evaluating the exposure to WBV and lumbar spine degeneration on imaging were included. Fifteen studies (16 manuscripts) were included. Seven studies including a meta-demonstrated moderate quality evidence of no association between WBV and disc degeneration. There was also moderate quality evidence of no association between WBV and disc height narrowing and osteophytes. Overall, there was low level evidence of no association between WBV and other degenerations findings. There was moderate to low quality evidence suggesting no association between WBV exposures with spine degeneration on imaging. The results of this study currently do not support assertion that motorized vehicle and WBV exposure accelerates degeneration and causes structural damage to the spine.

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.

Whole Body Vibration Exposure Transmitted to Drivers of Heavy Equipment Vehicles: A Comparative Case According to the Short- and Long-Term Exposure Assessment Methodologies Defined in ISO 2631-1 and ISO 2631-5.

The construction and transport sectors are the industries with the highest proportions of workers exposed to vibrations in the European Union. Heavy equipment vehicle (HEV) drivers often perform operations on different uneven surfaces and are exposed to whole body vibration (WBV) on a daily basis. Recently, a new version of ISO 2631-5 was published. However, since this new method required as input the individual exposure profile and the acceleration signals recorded on more surfaces, limited studies have been carried out to evaluate HEV operations according to this standard. The objectives of this study were to assess the WBV exposure using the methods defined in ISO 2631-1:1997 and ISO 2631-5:2018 and to compare the obtained health risk assessments between drivers with different anthropometric characteristics. For this purpose, two drivers were selected and a field measurement campaign was conducted. Regarding short-term assessment, results showed that VDV was the most restrictive method with exposure levels above the exposure action limit value, while indicated that the same exposures were safe for the worker. With respect to long-term assessment, Risk Factor RA showed that the driver with the highest body mass index was the only one who exceeded the low probability limit of adverse health effects.