Evidence of health risks associated with prolonged standing at work and intervention effectiveness.

PURPOSE: Prolonged standing at work has been shown to be associated with a number of potentially serious health outcomes, such as lower back and leg pain, cardiovascular problems, fatigue, discomfort, and pregnancy-related health outcomes. Recent studies have been conducted examining the relationship between these health outcomes and the amount of time spent standing while on the job. The purpose of this article was to provide a review of the health risks and interventions for workers and employers that are involved in occupations requiring prolonged standing. A brief review of recommendations by governmental and professional organizations for hours of prolonged standing is also included. FINDINGS: Based on our review of the literature, there seems to be ample evidence showing that prolonged standing at work leads to adverse health outcomes. Review of the literature also supports the conclusion that certain interventions are effective in reducing the hazards associated with prolonged standing. Suggested interventions include the use of floor mats, sit-stand workstations/chairs, shoes, shoe inserts and hosiery or stockings. Studies could be improved by using more precise definitions of prolonged standing (e.g., duration, movement restrictions, and type of work), better measurement of the health outcomes, and more rigorous study protocols. CONCLUSION AND CLINICAL RELEVANCE: Use of interventions and following suggested guidelines on hours of standing from governmental and professional organizations should reduce the health risks from prolonged standing.

Efficacy of the revised NIOSH lifting equation to predict risk of low-back pain associated with manual lifting: a one-year prospective study.

OBJECTIVE: The objective was to evaluate the efficacy of the Revised National Institute for Occupational Safety and Health (NIOSH) lifting equation (RNLE) to predict risk of low-back pain (LBP). BACKGROUND: In 1993, NIOSH published the RNLE as a risk assessment method for LBP associated with manual lifting. To date, there has been little research evaluating the RNLE as a predictor of the risk of LBP using a prospective design. METHODS: A total of 78 healthy industrial workers' baseline LBP risk exposures and self-reported LBP at one-year follow-up were investigated. The composite lifting index (CLI), the outcome measure of the RNLE for analyzing multiple lifting tasks, was used as the main risk predictor. The risk was estimated using the mean and maximum CLI variables at baseline and self-reported LBP during the follow-up. Odds ratios (ORs) were calculated using a logistic regression analysis adjusted for covariates that included personal factors, physical activities outside of work, job factors, and work-related psychosocial characteristics. RESULTS: The one-year self-reported LBP incidence was 32.1%. After controlling for history of prior LBP, supervisory support, and job strain, the categorical mean and maximum CLI above 2 had a significant relationship (OR = 5.1-6.5) with self-reported LBP, as compared with the CLI below or equal to I. The correlation between the continuous CLI variables and LBP was unclear. CONCLUSIONS: The CLI > 2 threshold may be useful for predicting self-reported LBP. Research with a larger sample size is needed to clarify the exposure-response relationship between the CLI and LBP.

Provisional recommended weight limits for manual lifting during pregnancy.

OBJECTIVE: The National Institute for Occupational Safety and Health (NIOSH) Revised Lifting Equation (RNLE) was adapted to derive recommended weight limits (RWLs) for pregnant workers and to develop corresponding guidelines for clinicians. BACKGROUND: In the past three decades there has been a large increase in the number of women employed outside the home and remaining in the workforce during pregnancy. Practical authoritative guidelines based on accumulated evidence are needed to inform allowable work activity levels for healthy pregnant workers. METHOD: Empirically based lifting criteria established by NIOSH to reduce the risk of overexertion injuries in the general U.S. working population were evaluated for application to pregnant workers. Our evaluation included an extensive review of the literature linking occupational lifting to maternal and fetal health. Decision logic and supporting literature are presented, along with computational details. RESULTS: Provisional RWLs for pregnant workers were derived from the RNLE, along with guidelines for clinicians. The guidelines advise against pregnant workers lifting below midshin and overhead. CONCLUSION: Based on our review of the available evidence, we present lifting thresholds that most pregnant workers with uncomplicated pregnancies should be able to perform without increased risk of adverse maternal and fetal health consequences. Except for restrictions involving lifting from the floor and overhead, the provisional guidelines presented are compatible with NIOSH lifting recommendations adopted in the early 1990s for the general working population. APPLICATION: Implementation of these provisional guidelines could protect millions of female workers in the workplace from fetal and maternal lifting-related health problems.

Clinical guidelines for occupational lifting in pregnancy: evidence summary and provisional recommendations.

Empirically based lifting criteria established by the National Institute for Occupational Safety and Health (NIOSH) to reduce the risk of overexertion injuries in the general US working population were evaluated for application to pregnant workers. This report proposes criteria to guide decisions by medical providers about permissible weights for lifting tasks performed at work over the course of an uncomplicated pregnancy. Our evaluation included an extensive review of the literature linking occupational lifting to maternal and fetal health. Although it has been 29 years since the American Medical Association's Council on Scientific Affairs published its report on the Effects of Pregnancy on Work Performance, these guidelines continue to influence clinical decisions and workplace policies. Provisional clinical guidelines derived from the NIOSH lifting criteria that account for recent evidence for maternal and fetal health are presented and aim to improve the standard of care for pregnant workers.

Ergonomic Assessment of Floor-based and Overhead Lifts.

Manual full-body vertical lifts of patients have high risk for developing musculoskeletal disorders. Two primary types of battery-powered lift assist devices are available for these tasks: floor-based and overhead-mounted devices. Studies suggest that the operation of floor-based devices may require excessive pushing and pulling forces and that overhead-mounted devices are safer and require lower operating forces. This study evaluated required operating hand forces and resulting biomechanical spinal loading for overhead-mounted lifts versus floor-based lifts across various floor surfaces and patient weight conditions. We did not examine differences in how operators performed the tasks, but rather focused on differences in required operating forces and estimated biomechanical loads across various exposure conditions for a typical operator. Findings show that the floor-based lifts exceeded recommended exposure limits for pushing and pulling for many of the floor/weight conditions and that the overhead-mounted lifts did not. As expected, forces and spinal loads were greater for nonlinoleum floor surfaces compared with linoleum floors. Based on these findings, it is suggested that overhead-mounted devices be used whenever possible, particularly in instances where carpeted floors would be encountered.

Efficacy of the revised NIOSH lifting equation to predict risk of low back pain due to manual lifting: expanded cross-sectional analysis.

OBJECTIVE: To evaluate whether the Revised NIOSH Lifting Equation (RNLE) is a valid tool for assessing risk of low back pain (LBP) due to manual lifting by using combined data from two cross-sectional studies of 1-year prevalence. METHODS: Results from a symptom and occupational history questionnaire and RNLE analysis for 677 subjects employed in 125 manual lifting jobs at nine industrial sites were combined from two studies. RESULTS: The odds of LBP increased as the lifting index (LI) increased from 1.0 to 3.0. A statistically significant odds ratio (OR) was found for both the 1 < LI ≤ 2 (OR = 1.81) and the 2 < LI ≤ 3 categories (OR = 2.26). For jobs with an LI value greater than 3.0, however, the OR remained nonsignificant. The 2 < LI ≤ 3 group remained statistically significant after adjusting for age, gender, body mass index, and psychosocial factors. CONCLUSIONS: It is clear that as the LI increases, the risk of LBP increases. Longitudinal studies are needed.

Trends in work-related musculoskeletal disorders: a comparison of risk factors for symptoms using quality of work life data from the 2002 and 2006 general social survey.

OBJECTIVE: To assess trends in risk factors for work-related musculoskeletal disorders (MSDs). METHODS: Results from two similar national surveys (2002 and 2006) examined trends in relationships between individual, psychosocial, and physical factors and MSDs. RESULTS: Findings between years were similar, but important differences included a stronger effect of "Work Stress" on "Pain in Arms," and a stronger combined effect of "Hand Movement" and "Work Stress" on "Pain in Arms." Also, two interactions were statistically significant in the 2006 data, but not in the 2002 data, revealing potentially increased risks. These were "Hand Movement" and "Work Stress" on "Back Pain," and "Heavy Lifting" and "Work Stress" on "Pain in Arms." CONCLUSION: New strategies for preventing both low back and upper extremity MSDs should focus on work stress, heavy lifting, and hand movement, individually and in combination.

Introduction to ergonomics for healthcare workers.

Healthcare workers who handle and move patients as part of their jobs suffer a disproportionately high number of work-related musculoskeletal disorders (MSDs). The majority of reported work-related MSDs are back pain cases that result in significant numbers of lost work days. It is likely that these lost workdays have a substantial impact on the quality and cost of health care. Patient care ergonomics can reduce the risk of work-related MSDs by helping safety experts design the work so it can be safely performed by most workers. This article provides a general overview of ergonomics--what it is, how it can be used to help design safe work, and why all healthcare workers and administrators should know and understand how excessive work demands can lead to increased risk of work-related MSDs. The article will also explain technological solutions that can be implemented to reduce the risk of work-related MSDs for healthcare workers.

Safe patient handling for rehabilitation professionals.

Every day, thousands of physical therapists and rehabilitation nurses are required to perform physically demanding therapeutic patient handling tasks that are stressful to the caregiver and increase his or her risk of developing work-related musculoskeletal disorders (MSDs). In rehabilitation, patient handling tasks might be classified as"traditional" or "therapeutic."Traditional tasks have a practical goal, such as transferring a patient from bed to a wheelchair, and therapeutic tasks have more targeted goals such as facilitating patient function and independence. Therapeutic patient handling tasks present a greater risk for caregivers to sustain work-related MSDs than typical patient handling tasks do because caregivers are exposed to high mechanical loads on the spinal tissues for longer amounts of time. The Veterans Health Administration, Association of Rehabilitation Nurses, and the American Physical Therapy Association endorse the use of modern patient handling technology as part of a comprehensive safe patient handling program for providing therapy in rehabilitation settings. Information about patient handling technology that is effective in reducing the risk of work-related MSDs from performing therapeutic patient handling and movement tasks is also presented and discussed in this article.

Two-dimensional biomechanical model for estimating strength of youth and adolescents for manual material handling tasks.

Youth and adolescents are routinely engaged in manual material handling (MMH) tasks that may exceed their strength capability to perform the task and may place them at excessive risk for musculoskeletal disorders. This paper reports on a two-dimensional biomechanical model that was developed to assess MMH tasks performed by youth 3-21 years of age. The model uses age, gender, posture of the youth performing the MMH activity, and weight of the load handled as input, and provides an estimate of the strength demands of the task and spinal disc compression and shear force resulting from the activity as output. The model can be used to assess whether a specific MMH task exceeds the strength demands for youth of certain ages or genders, which of the internal muscle strengths are most affected, and provides information about the estimated spinal disc compression and shear forces on the spine as a result of the specified MMH task. These results would be helpful in deciding whether a task is appropriate for a youth to perform or whether a certain task modification may be sufficient in reducing the physical demands to a level acceptable for a youth of certain age and gender.

Recommendations for vertical transfer of a postoperative total hip replacement patient (bed to chair, chair to toilet, chair to chair, or car to chair).

Vertical transfers of postoperative orthopaedic patients pose a high risk to healthcare workers for developing work-related musculoskeletal disorders. The task is considered high risk based on weight limits and awkward positioning. A task force including representatives from the National Association of Orthopaedic Nurses, the American Nurses Association, the National Institute for Occupational Safety and Health, the Patient Safety Center of Inquiry at the James A. Haley Veterans Administration Medical Center in Tampa, Diligent Services, and Guldmann, Inc., developed an ergonomic tool for determining best practices for safe vertical transfers. Current concepts of ergonomic safety, scientific evidence, and safe patient-handling equipment and devices were incorporated into this ergonomic tool.

Development of the National Association of Orthopaedic Nurses guidance statement on safe patient handling and movement in the orthopaedic setting.

High-risk patient-handling tasks lead to work-related musculoskeletal disorders for orthopaedic nurses and other members of the healthcare team who are involved in moving patients with orthopaedic issues. Serious consequences can arise from manually moving/lifting these patients. A task force was organized that included representatives from the National Association of Orthopaedic Nurses, the Patient Safety Center of Inquiry at the James A. Haley Veterans Administration Medical Center in Tampa, the National Institute for Occupational Safety and Health, and the American Nurses Association to identify high-risk tasks performed in the orthopaedic setting and to develop evidence-based solutions to minimize the risk of musculoskeletal disorders. High-risk tasks for moving and lifting orthopaedic patients were identified. Four orthopaedic algorithms and a clinical tool were developed by the task force to direct nurses and healthcare team members caring for orthopaedic patients through the use of scientific evidence and available safe patient-handling equipment and devices.

Recommendations for turning patients with orthopaedic impairments.

Nurses and other caregivers face high risk for developing work-related musculoskeletal disorders associated with turning (logrolling) patients with orthopaedic conditions. The task is considered high risk on the basis of weight limits and awkward positioning. A task force including representatives from the National Association of Orthopaedic Nurses the American Nurses Association, the National Institute for Occupational Safety and Health, the Patient Safety Center of Inquiry at the James A. Haley Veterans Administration Medical Center in Tampa, Diligent Services, and Guldmann, Inc., developed an ergonomic tool for determining best practices for safe patient turning. Scientific evidence, concepts of ergonomic safety, and safe patient handling equipment were incorporated into this ergonomic tool.

Recommended weight limits for lifting and holding limbs in the orthopaedic practice setting.

Nurses and other caregivers face high risk for developing work-related musculoskeletal disorders while lifting and holding limbs in the orthopaedic practice setting. A task force including representatives from the National Association of Orthopaedic Nurses, American Nurses Association, National Institute for Occupational Safety and Health, Patient Safety Center of Inquiry at the James A. Haley Veterans Administration Medical Center in Tampa, Diligent Services, and Guldmann, Inc., developed an orthopaedic clinical tool for determining maximum recommended weight limits for lifting and holding arms and legs for treatment of the orthopaedic patient. Scientific evidence, concepts of ergonomic safety, and safe patient-handling equipment were incorporated into this clinical tool.

Safe ambulation of an orthopaedic patient.

Nurses and other caregivers face high risk for developing work-related musculoskeletal disorders associated with manual ambulation of patients with orthopaedic conditions. In addition to the physical demands needed to support the patient's weight during ambulation, injury risk increases if the patient falls. A task force including representatives from the National Association of Orthopaedic Nurses, American Nurses Association, National Institute for Occupational Safety and Health, and Patient Safety Center of Inquiry at the James A. Haley Veterans Administration Medical Center in Tampa developed an ergonomic tool for determining best practices for safe ambulation of orthopaedic patients (C. A. Sedlak, M. O. Doheny, A. Nelson, & T. R. Waters, 2009). Scientific evidence, concepts of ergonomic safety, and safe patient-handling equipment were incorporated into an ergonomic tool designed to increase safety and reduce unnecessary variation in practice associated with this high-risk patient-handling task (National Institute for Occupational Safety Health, 1997; National Research Council/Institute of Medicine, 2001; A. Nelson, 2006; T. Waters, 2007).

Comparison of required operating forces between floor-based and overhead-mounted patient lifting devices.

This study investigated the differences in required push, pull and rotating forces for moving fully loaded, floor-based and overhead-mounted full body patient lifting devices with simulated patients of varying weight on a floor of optimal design (i.e. level vinyl tile over concrete). A single person operated the lifting devices for all of the tests. Eighteen male and female volunteer participants, ranging in weight from 51 to 146 kg, acted as patients during the lifting tests. For each test, the simulated patients were pushed and pulled for 3.7 linear metres and were rotated while sitting in the lift slings. Force measurements were acquired using two single axis dynamometers affixed to the lifting devices. Results revealed that, in general, operator input force and torque increased with patient weight category and floor-based lifts required greater force and torque compared to the overhead-mounted lift. Comparison of the required forces with published force limits reveals that the required push and pull force from the various patient lift systems, across all weight categories, were generally acceptable to 90% of the female population. The required forces for these patient transfer tasks, however, could exceed maximum acceptable force limits if the floor surfaces were less than ideal, such as floors composed of carpet, wood, or inclined surfaces. Additional research is needed to assess these conditions.

Investigation of select ergonomic interventions for farm youth. Part 1: shovels.

There is some evidence that performing farm chores may place youth at risk of musculoskeletal injuries. However, actual investigations of interventions for farm youth have been sparse. The objective of the current study was to investigate two different types of interventions (add-on handles) for shovels, potentially reducing the risk of injury in farm youth. A lumbar motion monitor was used to capture trunk posture and motion while the youth performed a simulated shoveling task--removal of material from an animal stall. Ratings of perceived exertion and comfort of use were also assessed. The results indicate add-on handles decreased sagittal flexion but increased twisting as compared to regular shovels. Perceived ratings were worse for shovels with add-on handles. Overall, there appears to be a trade-off between sagittal and nonsagittal motion and appears to have minimal impact on risk of low back injury. However, further research is necessary to determine the complete ramifications of this trade-off with respect to the biomechanical load within the low back and on other joints.

Investigation of select ergonomic interventions for farm youth. Part 2: wheelbarrows.

Previous research has provided evidence that farm youth performing farm chores may be at risk of developing a low back musculoskeletal injury. In order to reduce these risks, effective interventions for reducing the stressors that cause the injuries are needed. The objective of the current study was to investigate alternative wheelbarrow styles as an intervention for youth working to transfer material on the farm with respect to trunk motion and perceived exertion. A lumbar motion monitor was used to capture three-dimensional trunk kinematics while several wheelbarrow tasks (e.g., pushing, pushing over bump, and dumping) were performed by youth. Ratings of perceived exertion and comfort of use were also assessed. Results indicated a reduction in the sagittal trunk flexion and velocity was achieved by adding a push bar to the handles, in combination with three-wheels, or utilizing adjustable handles. However, these alterations had little impact in the predicted low back disorder risk levels. Additionally, the youths' perceptions of risk and exertion levels were greater for these alternative wheelbarrows than for the regular wheelbarrow. Therefore, the mismatch between perception and kinematic response will probably affect usage of the alternative wheelbarrows. While the results indicate that alternative wheelbarrow designs can reduce the awkward postures and motions during wheelbarrow tasks, further research into the effectiveness of these interventions, including spine loading and long long-term use, is necessary.