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Objective This review aimed to evaluate all studies that have evaluated the biomechanical effects when using assistive devices. Introduction The physical demands of patient handling activities are well known. One safety strategy for the reduction of the physical risks is use of assistive devices. Method The search process identified articles published in English-speaking journals through Google Scholar, Medline, and ISI Web of Science. The included 56 studies contained a biomechanical assessment of a patient handling activity with assistive devices. Results The biomechanical effects included four groups: changes in body posture (spinal, other joints), subjective assessment (force, effort, discomfort), measured force (hand force, ground reaction force, spine force, joint torque), and physiological measures. The evidence showed caregivers benefited from using lift hoists, air-assisted devices, and to a lesser extent friction reducing devices for lateral transfers and repositioning, while floor and ceiling lifts were most effective for patient transfers. Some gaps were noted in the evidence and other handling tasks such as sit-to-stand, turning patient in bed, limb lifting, and repositioning and some more high hazard activities like supporting people with limited balance and those that fall need to be investigated with respect to biomechanical outcomes. Conclusion There is a growing level of biomechanical evidence to support the use of assistive devices for many patient-handling tasks, but the benefits of equipment use in some transfers remain uninvestigated. Practical Application Evidence indicates the best way to lift patients safely is with floor or ceiling lifts, and air-assisted devices for lateral and repositioning tasks.

Objective: The aim of this study was to assess the contributions of Thomas Waters's work in the field of health care ergonomics and beyond. Background: Waters's research of safe patient handling with a focus on reducing musculoskeletal disorders (MSDs) in health care workers contributed to current studies and prevention strategies. He worked with several groups to share his research and assist in developing safe patient handling guidelines and curriculum for nursing students and health care workers. Methods: The citations of articles that were published by Waters in health care ergonomics were evaluated for quality and themes of conclusions. Quality was assessed using the Mixed Methods Appraisal Tool and centrality to original research rating. Themes were documented by the type of population the citing articles were investigating. Results: In total, 266 articles that referenced the top seven cited articles were evaluated. More than 95% of them were rated either medium or high quality. The important themes of these citing articles were as follows: (a) Safe patient handling is effective in reducing MSDs in health care workers. (b) Shift work has negative impact on nurses. (c) There is no safe way to manually lift a patient. (d) Nurse curriculums should contain safe patient handling. Conclusion: The research of Waters has contributed significantly to the health care ergonomics and beyond. His work, in combination with other pioneers in the field, has generated multiple initiatives, such as a standard safe patient-handling curriculum and safe patient-handling programs.

ObjectiveThe aim of this study was to determine the prevalence of musculoskeletal pain and reported injuries for nurses and nursing aides.BackgroundNurses and nursing aides suffer from work-related pain and musculoskeletal disorders (MSDs). Although there have been a plethora of studies on MSDs, an overall understanding of the prevalence of MSDs and pain can lead to better prioritization of research needs with respect to the health care industry.MethodA total of 132 articles on prevalence of MSD pain and injuries were included in the review. All articles were published in peer-reviewed English-speaking journals and subjected to a quality review.ResultsReported prevalence of MSD pain for nurses and nursing aides was highest in the low back, followed by shoulders and neck. However, the majority of the studies have been concentrated on 12-month pain in the low back and predominantly in hospitals. Few researchers have investigated pain in the upper and lower extremities (less than 27% of the studies). Even fewer researchers have evaluated reported injuries or even subjective lost-time injuries (less than 15% of the studies).ConclusionMSD pain in the nursing profession has been widely investigated worldwide, with a major focus on low-back pain. Given new directions in health care, such as patients who live longer with more chronic diseases, bariatric patients, early mobility requirements, and those who want to be at home during sickness, higher prevalence levels may shift to different populations—home health care workers, long-term care workers, and physical therapists—as well as shift to different body regions, such as shoulders and upper extremities.

Objective: This article investigates whether different interventions aimed at promoting postural change could increase body movement throughout the shift and reduce musculoskeletal discomfort. Background: Many researchers have reported high levels of discomfort for workers that have relatively low-level demands but whose jobs are sedentary in nature. To date, few interventions have been found to be effective in reducing worker discomfort. Methods: Thirty-seven call center operators were evaluated in four different workstation conditions: conventional workstation, sit-stand workstation, conventional workstation with reminder software, and sit-stand workstation with break reminder software–prompt to remind workers to take break. The primary outcome variables consisted of productivity, measured by custom software; posture changes, measured by continuous video recording; and discomfort, measured by simple survey. Each condition was evaluated over a 2-week period. Results: Significant reductions in short-term discomfort were reported in the shoulders, upper back, and lower back when utilizing reminder software, independent of workstation type. Although not significant, many productivity indices were found to increase by about 10%. Conclusions: Posture-altering workstation interventions, specifically sit-stand tables or reminder software with traditional tables, were effective in introducing posture variability. Further, postural variability appears to be linked to decreased short-term discomfort at the end of the day without a negative impact on productivity. Applications: An intervention that can simply induce the worker to move throughout the day, such as a sit-stand table or simple software reminder about making a large posture change, can be effective in reducing discomfort in the worker, while not adversely impacting productivity.

Typically, the simplest and most cost-efficient ergonomic solution to offset the rising costs of low back injuries is to reduce the box weight that is lifted. However, there is limited research on how a worker interacts with the box. In the present study, we quantify the utility of reducing the weight that is lifted---specifically, how changes in the box weight affect trunk kinematics, trunk moments, and ultimately, spinal loads. In the experiment, 15 participants lifted a variety of box weights (from 9.1 to 41.7 kg) from knee height, carried it a distance of 5 feet (1.5 m), and placed it on a shelf at elbow height. For the lower weights, small increases in box weight (3-9 kg) were offset by the trunk dynamics (sagittal velocity), resulting in no difference in spinal loads. At the same time, spinal loads were found to be significantly higher for weights above 25 kg. Thus, when making ergonomic changes (reduction of box weight), it is important to consider how workers will interact with the box. These results indicate that purely weight-based ergonomic controls might not sufficiently reduce the risk of low back disorders. Furthermore, this study provides additional evidence of the utility of using more complex spinal load models (dynamic, multiple muscle models) when evaluating highly dynamic and complex tasks.

AbstractObjectivesNearly all workers and industry sectors have been affected by the ongoing coronavirus disease 2019 (COVID-19) pandemic in some form since March 2020. However, the pandemic-related stressors experienced in the workplace may vary from industry to industry and may have disproportionally affected some workers. This study investigates increased stress levels, stressor events, and other perceptions of stress from at-risk workers during COVID-19.MethodsAn in-depth work-related stress survey that incorporated many aspects of work, life, work-life balance, and the health of employer-employee relationships was developed with a focus on COVID-19-related stressors. The cross-sectional survey was distributed online through professional networks from October to November 2021. The survey results were statically analyzed using Kruskal–Wallis one-way analysis of variance (ANOVA) after grouping the industry sectors into the four groups to determine trends within these groupings.ResultsThe survey was completed by 670 workers in sectors such as manual labor, business/office service, healthcare, and education. A variety of trends were determined between the occurrence of COVID-19 and work stress which had, in some cases, affected some industry sectors to a larger degree than others. More than 50% of the participants reported experiencing an increased workload since the onset of the pandemic with some sectors, like healthcare, reporting an increased workload more frequently at 80%. Around 55% of respondents believed they could be exposed to COVID-19 in their workplace, ranging from 52% of business/office service workers to 77% of healthcare workers.ConclusionsAs workplaces navigate past the pandemic, occupational stress should be addressed head-on through workplaces providing expanded resources so as to assure work stress associated with future pandemics are mitigated appropriately. Whether the stressor is associated with irregular shift work or psychosocial aspects (i.e. relying on coworkers), many of these stressors have the possibility to become exacerbated by external factors such as pandemics.

Objective: To determine if lifting random unknown weights is more detrimental than lifting sequences of unknown weights and to investigate whether load knowledge impacts the effect of lifting random box weights. Background: Much research has investigated lifting under known load conditions, but few studies have investigated unknown loads, especially when presented in random order. There has been some documentation of alteration in trunk mechanics when there is an overestimation of the unknown load. Method: Ten men and 10 women performed three lifting tasks: random unknown, random known, and same weight. A lumbar motion monitor was used to collect kinematic data, and Borg's Rating of Perceived Exertion (RPE) and a task risk rating were also assessed. Results: Both presentation order and load knowledge impacted trunk kinematics during repeated lifting tasks. However, these differences were relatively low in magnitude. Furthermore, kinematic response and perceived risk and exertion for these conditions varied between genders. Conclusion: Lifting random unknown loads appears to alter kinematic responses, particularly for men. Women attempt to modify the effect of random unknown loads by changing the lifting style through alterations in upper limb motions (e.g., drag box toward them prior to lifting). However, a need remains for a more comprehensive biomechanical investigation (e.g., spine loading) into the effects of random unknown loads because many of the effect sizes were small. Application: Small kinematic adaptations resulting from tasks involving unknown and random loads may be mediated by the use of visual cues, order of presentation, or a change in lifting style.

Objective: The study objective was to quantify the movement of hospital bed occupants relative to the bed in typical bed articulations. Background: Movement of a patient in bed results in two common adverse events: (a) increase in shear and friction forces between the patient and bed, which are extrinsic pressure ulcer risk factors, and (b) musculoskeletal injuries to nurses, resulting from repositioning patients who have migrated down in bed. Method: The study involved 12 participants who lay supine in three hospital beds, which were articulated to common positions. Body movement relative to the bed was quantified with the use of motion capture. Cumulative movement, net displacement, and torso compression (shoulder to trochanter distance) were calculated for different bed types and bed movements. Results: Bed design and bed movement had a significant effect on most of the dependent variables. Bed design (e.g., type) influenced cumulative movement by up to 115%, net displacement by up to 70%, and torso compression by about 20%. Bed movement (e.g., knee elevation) reduced cumulative migration by up to 35%. Conclusion: The quantification of patient migration provides a metric for evaluating the interaction between body and bed surfaces. Overall, the measures were sensitive to design changes in bed frames, bed articulations, and mattress inflation. Application: Documentation of the cumulative movement, net displacement, and torso compression provides hospital bed designers quantifiable measures for reducing migration and potentially shear and friction forces when designing bed frames, bed articulations, and mattresses. Optimization of these metrics may ultimately have an impact on patient and caregiver health.

Objective To evaluate neck muscle coactivation across different levels of mental workload during simulated flight tasks. Background Neck pain (NP) is highly prevalent among military aviators. Given the complex nature within the flight environment, mental workload may be a risk factor for NP. This may induce higher levels of neck muscle coactivity, which over time may accelerate fatigue, increase neck discomfort, and affect flight task performance. Method Three counterbalanced mental workload conditions represented by simulated flight tasks modulated by interstimulus frequency and complexity were investigated using the Modifiable Multitasking Environment (ModME). The primary measure was a neck coactivation index to describe the neuromuscular effort of the neck muscles as a system. Additional measures included perceived workload (NASA TLX), subjective discomfort, and task performance. Participants ( n = 60; 30M, 30F) performed three test conditions over 1 hr each while seated in a simulated seating environment. Results Neck coactivation indices (CoA) and subjective neck discomfort corresponded with increasing level of mental workload. Average CoAs for low, medium, and high workloads were: .0278(SD = .0232), .0286(SD = .0231), and .0295(SD = .0228), respectively. NASA TLX mental, temporal, effort, and overall scores also increased with the level of mental workload assigned. For ModME task performance, the overall performance score, monitoring accuracy, and resource management accuracy decreased while reaction times increased with the increasing level of mental workload. Communication accuracy was lowest with the low mental workload but had higher reaction times relative to increasing workload. Conclusion Mental workload affects neck muscle coactivation during combinations of simulated flight tasks within a simulated helicopter seating environment. Application The results of this study provide insights into the physical response to mental workload. With increasing multisensory modalities within the work environment, these insights may assist the consideration of physical effects from cognitive factors.

Objective:The objective of this article is to evaluate the impact of the Revised National Institute for Occupational Safety and Health Lifting Equation (RNLE).Background:The RNLE has been used extensively as a risk assessment method for prevention of low back pain (LBP). However, the impact of the RNLE has not been documented.Methods:A systematic review of the literature on the RNLE was conducted. The review consisted of three parts: characterization of the RNLE publications, assessment of the impact of the RNLE, and evaluation of the influences of the RNLE on ergonomic standards. The literature for assessing the impact was categorized into four research areas: methodology, laboratory, field, and risk assessment studies using the Lifting Index (LI) or Composite LI (CLI), both of which are the products of the RNLE.Results:The impact of the RNLE has been both widespread and influential. We found 24 studies that examined the criteria used to define lifting capacity used by the RNLE, 28 studies that compared risk assessment methods for identifying LBP, 23 studies that found the RNLE useful in identifying the risk of LBP with different work populations, and 13 studies on the relationship between LI/CLI and LBP outcomes. We also found evidence on the adoption of the RNLE as an ergonomic standard for use by various local, state, and international entities.Conclusion:The review found 13 studies that link LI/CLI to adverse LBP outcomes. These studies showed a positive relationship between LI/CLI metrics and the severity of LBP outcomes.

Objective:This article evaluates the effectiveness of two interventions: a self-leveling pallet carousel designed to position the loads vertically and horizontally at origin, and an adjustable cart designed to raise loads vertically at destination to reduce spine loads.Background:Low back disorders among workers in manual material handling industries are very prevalent and have been linked to manual palletizing operations. Evidence into the effectiveness of ergonomic interventions is limited, with no research that investigates interventions with adjustable load location.Method:Thirteen males experienced in manual material handling participated in simulated order selecting tasks where spine loads were quantified for each intervention condition: carousel to traditional cart, pallet to traditional cart, pallet to adjustable cart, and carousel to adjustable cart.Results:The results showed that combining both devices results in reduction in spine compression (61%), anterior-posterior shear (72%), and lateral shear (63%) compared to traditional palletizing conditions. Individually, the carousel was responsible for the greatest reductions, but the lowest values were typically achieved by combining the adjustable cart and carousel.Conclusion:The combination of the interventions (self-leveling carousel and adjustable cart) was most effective in reducing the spine loads when compared to the traditional pallet-cart condition. The individual interventions also reduced the loads compared to the traditional condition.Application:With de-palletizing/palletizing tasks being a major source of low back injuries, the combination of self-leveling carousel and adjustable cart has been found to be effective in reducing the peak spine loading as compared to traditional pallet on floor and nonadjustable flat cart conditions.

An experiment was performed to determine whether maximum acceptable weight of lift (MAWL) estimates were consistent with previously reported values when the MAWL was determined without visual feedback during the weight adjustment period. Twelve healthy male students performed four lifting tasks similar to those often performed in previous psychophysical studies: floor to knuckle at 1 lift per min, floor to knuckle at 4.3 lifts per min, knuckle to shoulder at 1 lift per min, and knuckle to shoulder at 4.3 lifts per min. When compared with the previous studies with similar box dimensions, similar trends between the conditions were present, but a slight reduction in weight was usually chosen by the participant in this study. However, the results of this study agreed with previous psychophysical studies when the distance of the load from the spine (moment arm) was taken into consideration by either comparing the MAWLs with those of a large box or by comparing load moments. Hence this study shows that eliminating visual feedback during the adjustment periods did not significantly alter the MAWLs from previous studies. It also indicates that one must use caution when applying the MAWL in the workplace because the MAWL is very sensitive to moment arm.

Abstract

Objectives
Despite a rise in automation, workers in the petroleum refining and petrochemical manufacturing industry are potentially exposed to various chemicals through inhalation while performing routine job duties. Many factors contribute to the degree of exposure experienced in this setting. The study objective was to characterize the impact of workplace conditions, anthropometric variability, and task orientation on exposure for a simulated routine operations task.


Methods
A chemical exposure laboratory simulation study was designed to evaluate the dependent variable of chemical exposure level in the breathing zone for methane and sulfur hexafluoride. The independent variables were (i) posture of the worker, (ii) worker anthropometry, (iii) process configuration, and (iv) gas density.


Results
Pipe height was a significant predictor of gas concentration measured in the breathing zone when located in a position that encouraged the gas to enter the breathing zone of the worker. Worker anthropometry had a major impact; tall worker's (male) chemical concentrations exceeded those of the short worker (female) for methane simulations but the opposite resulted for sulfur hexafluoride. Also, worker posture had a significant impact on gas exposure where nonneutral postures were found to have higher levels of chemical concentration.


Conclusions
The study findings indicate that the breathing zone location is altered by posture and worker height, which changes the exposures relative to the emission source depending on the gas density of the chemicals that are present. As a result, qualitative risk assessment cannot be performed accurately without accounting for these factors. Practically, controls may need to account for worker size differences and posture adaptations.