Whole-body Vibration Exposure Intervention among Professional Bus and Truck Drivers: A Laboratory Evaluation of Seat-suspension Designs

Vibratory Impact of 3 Different Ambulance Suspension Systems on the Simulated Neonate and Health Care Provider During Normal Driving Conditions

OBJECTIVE

Patients and health care providers experience varying degrees of vibration during interfacility ground transport. The impact of vibration on term and preterm neonates may result in physiologic instability and increased risk of intracranial hemorrhage, whereas the impact on health care providers has been shown to include an increase in perceived and physiologic stress levels and may contribute to chronic back and neck pain. This study aimed to evaluate 3 common ambulance suspension systems and the corresponding vibratory impact produced during typical interfacility driving conditions on adult caregiver and neonatal patient mannequins.

METHODS

Type 3 ambulances with air, liquid, and traditional suspensions were evaluated using various driving tests to simulate typical road conditions. Vibrations were measured using triaxial accelerometers placed on the chassis, upon the head of a seated caregiver mannequin in the ambulance bench seat, and the head of a neonatal mannequin supine and secured in an isolette. Data analysis included the average vibration frequency, root mean square values, and maximum vibration amplitudes.

RESULTS

The results showed that the supine neonatal mannequin experienced the highest vibration frequency and amplitude in the vertical (x) direction, whereas the adult caregiver mannequin experienced higher vibration frequencies in both parallel (y) and lateral (z) directions and the highest vibration amplitude in the y direction. The liquid suspension system consistently demonstrated the lowest vibration levels in all driving conditions and directions, whereas traditional suspension had the highest values.

CONCLUSION

This study provides important insights into the vibrations incurred by simulated neonatal patients and health care providers during ambulance transport. The directional vibration frequency and amplitude differ between a neonatal mannequin and an adult mannequin when placed in typical positions with typical restraints during varied ambulance driving conditions. In all directional movements and driving conditions, a liquid suspension system decreases vibration frequency and amplitude more than air or traditional systems. The live patient and caregiver impact of these results should be further investigated.

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 SdA indicated that the same exposures were safe for the worker. With respect to long-term assessment, Risk Factor R^A showed that the driver with the highest body mass index was the only one who exceeded the low probability limit of adverse health effects.

The effects of a new seat suspension system on whole body vibration exposure and driver low back pain and disability: Results from a randomized controlled trial in truck drivers

Through a randomized controlled trial, we evaluated the effects of an electro-magnetic active seat suspension that reduces exposure of a long-haul truck driver to whole body vibration (WBV) on low back pain (LBP) and disability. Among 276 drivers recruited from six trucking terminals of a major US trucking company, 135 eligible drivers were assigned to either having an Active Seat (Intervention: n = 70) - the BoseRide® electro-magnetic active seat - or Passive Seat (reference: n = 65) - a new version of their current seat (passive air suspension seat) - installed in their truck via block (terminal) randomization. Low back pain (LBP) severity, on a 0-10 scale and the Oswestry LBP Disability Index were collected before and 3-, 6-, 12-, 18-, and 24-months post seat installation. LBP severity and LBP disability scores were significantly lower post seat installation in both groups. At 3 months, LBP severity decreased -1.4 [95% CI: -2.1 to -0.7: n = 46] for drivers in the Active Seat arm, and -1.5 [95% CI: -2.3 to -0.8: n = 41] for drivers in the Passive Seat arm. In a subset of drivers, WBV exposures were collected before and after the seat installation. WBV exposures significantly decreased post seat installation for Active Seat (p < 0.01) but not for Passive Seat (p = 0.15). While the new seat-suspension technology reduced WBV exposures, LBP appeared to be improved by multiple factors. These results were limited by the secondary prevention approach and the longer-term loss to follow up due to large rates of driver turnover typical for the industry.

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.

Advancing the Safety, Health, and Well-Being of Commercial Driving Teams Who Sleep in Moving Semi-Trucks: The Tech4Rest Pilot Study

OBJECTIVE

To test the feasibility, acceptability, and potential effectiveness of engineering and behavioral interventions to improve the sleep, health, and well-being of team truck drivers (dyads) who sleep in moving semi-trucks.

METHODS

Drivers (n = 16) were exposed to Condition A: a new innerspring mattress, and Condition B: a novel therapeutic mattress. A subsample of drivers (n = 8) were also exposed to Condition C: use of their preferred mattress (all chose to keep B), switching to an active suspension driver's seat, and completing a behavioral sleep-health program. Primary outcomes were sleep duration, sleep quality, and fatigue. Behavioral program targets included physical activity and sleep hygiene.

RESULTS

Self-reported sleep and fatigue improved with mattress A, and improved further with mattress B which altered vibration exposures and was universally preferred and kept by all drivers. Condition C improved additional targets and produced larger effect sizes for most outcomes.

CONCLUSIONS

Results support these interventions as promising for advancing team truck drivers' sleep, health, and well-being.

Workplace environment of earth-moving machine operators in terms of anthropometric data development in the Slovak republic

BACKGROUND

Population data are gathered using the sampling unit at the appropriate time and due to various reasons (e.g. nutrition survey of the population, style of living, etc.), they can be changed due to trends for longer periods of time.

OBJECTIVE

The aim of the paper is to analyse selected anthropometric parameters relevant to the design of the earth-moving machine operator workplace environment and to compare the gathered data to the standard ISO 3411.

METHODS

The set of five dimensions and factors of the Slovak adult male population was analysed over the course of the years 2002-2018.

RESULTS

A significant increase in the parameter -body weight was observed. In total, mentioned dimension of male population increased by 0.4 kg (0.5%) during the time of analysis. Following the dot plot and linear regression equation the fact that the trend in growth is becoming a global phenomenon in Slovakia can be stated.

CONCLUSIONS

In the future, it will be necessary to focus on updating the standards defining the workplace size in this industry sector as well as in others.

Identifying Equipment Factors Associated with Snowplow Operator Fatigue

A recent body of research in fatigue management indicates that other factors, including in-cab and external equipment, contribute to operator fatigue. The goal of this project was to identify winter road maintenance equipment (in-cab and external) that may increase or mitigate snowplow operator fatigue. To accomplish this goal, questionnaires from 2011 snowplow operators were collected from 23 states in the U.S. Results confirmed previous research that fatigue is prevalent in winter road maintenance operations. Winter road maintenance equipment that produced excessive vibrations, noise, reduced visibility, and complex task demands were found to increase snowplow operators’ self-reported fatigue. Similarly, equipment that reduced vibrations and external noise, improved visibility, and limited secondary tasks were found to reduce snowplow operator’s self-reported fatigue. Based on the questionnaire responses and the feasibility of implementation, the following equipment may help to mitigate or prevent snowplow operator fatigue: dimmable interior lighting, LED bulbs for exterior lighting, dimmable warning lights, a CD player or satellite radio in each vehicle, heated windshield, snow deflectors, narrow-beam auxiliary lighting, and more ergonomically designed seats with vibration dampening/air-ride technology.

Prioritization of practical solutions for the vibrational health risk reduction of mining trucks using fuzzy decision making

The goal of this article was to prioritize the practical solutions for vibrational health risk reduction of truck drivers during mining operation using the multicriteria decision-making (MCDM) techniques. Mining trucks require special consideration because of their specific suspension system, large size, payload capacity, and off-road conditions of mining. In most cases, it is not easy for decision makers to compute verbal and linguistic variables, whose values are expressed in linguistic terms. These uncertainties and ambiguities are well interpreted by using fuzzy set theory. In this study, the MCDM methods were used under fuzzy environment. As a result, seat suspension maintenance was offered as the best solution to attenuate the vibrations and decrease the injuries related to the WBV exposure. The driver training, haul road construction and maintenance, lighting and visibility improvement and work organization were found as the other solutions, respectively.

A Randomized Controlled Trial of a Truck Seat Intervention: Part 2-Associations Between Whole-Body Vibration Exposures and Health Outcomes

This randomized controlled trial study was conducted to determine whether two different seating interventions would reduce exposure to whole-body vibration (WBV) and improve associated health outcomes. Forty professional truck drivers were randomly assigned to two groups: (i) a control group of 20 drivers who received a new, industry-standard air-suspension seat, and (ii) an intervention group of 20 drivers who received an active-suspension seat. This study collected regional body pain (10-point scale), low back disability [Oswestry Disability Index (ODI)], physical and mental health [the Short Form 12-item Health Survey (SF-12)], and work limitations [Work Limitation Questionnaire (WLQ)] before and 3, 6, and 12 months after the seating intervention. WBV exposures were also collected during the same time periods. Due to dropouts at the 12-month time period, only data up to 6 months post-intervention were included in the analyses. The post-intervention A(8) WBV exposures were lower in both groups with a more substantial WBV exposure reduction (~50%) in the intervention group compared to the control group (~26%). There was little to no change in the impulsive exposures [VDV(8) and Sed(8)] post-intervention and no differences between the two groups. The self-reported musculoskeletal health outcomes showed that intervention group experienced a greater reduction in the low back pain (LBP) and other musculoskeletal outcomes than the control group. The LBP reduction in the intervention group was clinically meaningful (>25%); however, none of the changes in pain reached statistical significance (P's > 0.22). The SF-12 health scores demonstrated that the intervention group's physical health improved after the intervention (P's < 0.06) while the control group experience little to no improvement (P's > 0.11). The WLQ scores showed that the intervention group generally experienced reduced (improved) work limitation over time whereas the control group showed inconsistent changes in work limitation scores. These study findings indicate that reducing truck drivers' exposure to WBV through seating intervention can lead to improvements in LBP and other health outcomes.

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

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

The effect of a multi-axis suspension on whole body vibration exposures and physical stress in the neck and low back in agricultural tractor applications

Whole body vibration (WBV) exposures are often predominant in the fore-aft (x) or lateral (y) axis among off-road agricultural vehicles. However, as the current industry standard seats are designed to reduce mainly vertical (z) axis WBV exposures, they may be less effective in reducing drivers' exposure to multi-axial WBV. Therefore, this laboratory-based study aimed to determine the differences between a single-axial (vertical) and multi-axial (vertical + lateral) suspension seat in reducing WBV exposures, head acceleration, self-reported discomfort, and muscle activity (electromyography) of the major muscle of the low back, neck and shoulders. The results showed that the multi-axial suspension seat had significantly lower WBV exposures compared to the single-axial suspension seats (p' < 0.04). Similarly, the multi-axial suspension seat had lower head acceleration and muscle activity of the neck, shoulder, and low back compared to the single-axial suspension seat; some but not all of the differences were statistically significant. These results indicate that the multi-axial suspension seat may reduce the lateral WBV exposures and associated muscular loading in the neck and low back in agricultural vehicle operators.

Whole-body vibration induces pain and lumbar spinal inflammation responses in the rat that vary with the vibration profile

Whole-body vibration (WBV) is linked epidemiologically to neck and back pain in humans, and to forepaw mechanical allodynia and cervical neuroinflammation in a rodent model of WBV, but the response of the low back and lumbar spine to WBV is unknown. A rat model of WBV was used to determine the effect of different WBV exposures on hind paw behavioral sensitivity and neuroinflammation in the lumbar spinal cord. Rats were exposed to 30 min of WBV at either 8 or 15 Hz on days 0 and 7, with the lumbar spinal cord assayed using immunohistochemistry at day 14. Behavioral sensitivity was measured using mechanical stimulation of the hind paws to determine the onset, persistence, and/or recovery of allodynia. Both WBV exposures induce mechanical allodynia 1 day following WBV, but only the 8 Hz WBV induces a sustained decrease in the withdrawal threshold through day 14. Similarly, increased activation of microglia, macrophages, and astrocytes in the superficial dorsal horn of the lumbar spinal cord is only evident after the painful 8 Hz WBV. Moreover, extracellular signal-regulated kinase (ERK)-phosphorylation is most robust in neurons and astrocytes of the dorsal horn, with the most ERK phosphorylation occurring in the 8 Hz group. These findings indicate that a WBV exposure that induces persistent pain also induces a host of neuroimmune cellular activation responses that are also sustained. This work indicates there is an injury-dependent response that is based on the vibration parameters, providing a potentially useful platform for studying mechanisms of painful spinal injuries. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1439-1446, 2016.

Comparative cross-sectional study for understanding the burden of low back pain among public bus transport drivers

BACKGROUND

Even though low back pain (LBP) is common, some occupations pose a higher risk. Identifying these occupations and specific factors will help to reduce the suffering and burden. This study aims to compare the prevalence of chronic LBP among bus drivers and to find its association with some occupational factors.

MATERIALS AND METHODS

It is a cross-sectional study to compare prevalence of LBP and factors associated with it, in two groups of drivers (n = 178) and nondrivers (n = 184).

RESULTS

The 10 years' percentage prevalence of LBP was found to be 70.8 and 51.6 among drivers and nondrivers respectively, whereas point prevalence in the same was 64.0 and 44.6. Drivers are at a higher risk for LBP with Odds ratio-2.270 (1.471-3.502). Risk factors such as prolonged sitting in one posture, night shifts, job dissatisfaction, tobacco use, and lack of exercise were significantly higher among drivers. Though the prevalence and intensity of LBP was higher among drivers, their number of leaves and hospital admitted days were less among drivers.

CONCLUSION

This is a potential group for intervention as prevalence of LBP, neck pain, and most of the suspected risk factors were higher among the drivers. Drivers got less recovery time and had higher sequelae.