Ergonomics is the science of properly balancing job demands with worker capabilities to prevent a mismatch in demands and capabilities which will lead to cumulative trauma of the body. Using the traditional industrial hygiene methodology of “anticipation, recognition, evaluation, and control” discussions will cover each area of the methodology as it applies to the field of occupational ergonomics. Reflections of occupational ergonomics in the past, the current state of the field, and considerations for the future of the field will also be presented.
Emergency department healthcare workers are known to face a unique combination of pressures from their careers and work environments regularly. Caring for dying patients and making difficult lifesaving decisions not only continued but also became more prevalent for emergency department healthcare workers during the COVID-19 pandemic. A growing body of literature revealed that the mental and emotional toll of COVID-19 has been tremendous. However, the burden of COVID-19 on the overall physical health and work–life balance on this group needs to be understood. This study aimed to describe the impact of stress on wellbeing and health across the globe among emergency department healthcare workers. A cross-sectional survey comprising work–family and family–work conflict scale, work–life balance, physical symptoms inventory, Oldenburg Burnout Inventory, satisfaction with job and life, and life change index scale was distributed to a convenience sample through listservs and social media. In total, 287 participants responded, 109 completing all questions. Fatigue was the most common symptom reported to occur daily (28.4%, n = 31), followed by muscle pain (13.8%, n = 15) and backache (11.9%, n = 13). Nurse practitioners reported the highest number of physical symptoms and the highest average scores and counts of stressful life events, while registered nurses indicated the highest work–family conflict levels. Linear regressions showed that stressful life events are significantly associated with both physical symptoms and work–family conflict. Results underscore the need to better support emergency department workers to mitigate the risks associated with occupational stress. Protective organizational policies and increased support strategies may be employed to improve wellbeing and cultivate a more sustainable workforce.
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.
This study evaluated the differences in spinal loading between males and females while performing complex free-dynamic whole body lifts. Twenty males and twenty-five females performed sagittally symmetric and asymmetric lifting tasks from mid-shin and knee height origins. Only minor differences between males and females were found in three-dimensional spinal loads. The compressive loads for the females appeared to be independent of the experimental condition (e.g. lifting task or velocity). Females adopted a different kinematic pattern compared to males as well as recruited more antagonistic muscles when performing similar tasks. When spinal tolerance differences are considered, females would be expected to be more at risk of injury during typical lifting tasks.
Background . Musculoskeletal disorders have continued to plague nurses in hospitals and long-term care facilities. Low back and shoulder injuries are the most prevalent, frequently linked to patient handling activities. Exposure to patient handling has been predominantly quantified by subjective responses of nurses. Objective . To directly observe handling of patients and other medical equipment for nurses during a 12-hour work shift. Methods . Twenty nurses working in three different intensive care units at a Midwest teaching hospital were directly observed during 12-hour day shifts. Direct observation included documenting frequency and type of handling performed and whether lift assist devices were utilized. Two additional surveys were completed by nurses to assess current pain levels and perceptions of lifting being performed. The observed lifting was compared to the perceived lifting with simple inference statistics. Results . Nurses have a high prevalence of manually lifting patients and medical devices but limited use of lifting assist devices. Nurses handled patients 69 times per shift and medical equipment 6 times per shift, but less than 3% utilized a lift assist device. Nurses suffered from high levels of pain at the end of the shift, with the highest prevalence in the lower back, lower legs, and feet/ankles (all above 60%).
With the rising costs of low back injuries, one low cost ergonomic solution would be to reduce the weight. But, limited research has investigated how the worker interacts with the box. This study evaluated how lifting different box weights effects the trunk kinematics, horizontal moment arm, and resulting spinal loads. Fifteen participants lifted a box weighing 9.1, 11.8, 14.5, 17.2, 20.0, 29.9, 32.7, 35.4, 38.1, and 41.7 kg., from knee height, carried it a distance of five feet, and placed it on a shelf at elbow height. The present study quantifies the utility of reducing the weight lifted. Small changes in weight were found to only slightly influence the trunk kinematics and spinal loads. The accuracy of the spinal load estimates were found to be influenced by the trunk dynamics and changes in horizontal moment arm, especially for the lighter weights evaluated in this study. These results can be used to establish potential weight limits to assist in the ergonomic redesign of a manual material handling task.
In Brief Study Design. Spine loadings during a variety of lifting exertions were compared with individual torso kinematic abilities. Relationships were evaluated between these measures. Objective. To determine if trunk kinematic status (functional impairment) is indicative of spine loading increases in patients with low back pain (LBP) compared to asymptomatic individuals. Summary of Background Data. Recurrent LBP is a common and costly problem that may be related to increased spine loads in those individuals with LBP. Previous studies suggest that patients with LBP had greater loading than their asymptomatic counterparts when performing work. However, we know little about how to identify when a patient with LBP can resume lifting tasks without having exaggerated spine loading. Methods. Sixty-two patients with LBP and 61 who were asymptomatic were evaluated for signs of kinematic compromise (i.e., inability to generate normal trunk kinematic patterns) during a prelift test. All subjects were then asked to perform a variety of lifting exertions that varied in lift origin (region), lift asymmetry position, and weight lifted. An electromyography-assisted model was used to evaluate spine loading in each subject during the lifting exertions. Statistical models were used to assess the relationship between kinematic compromise and spine loading. Results. Patients with LBP had greater spine loading as well as greater kinematic compromise. The degree of kinematic compromise was related to the degree of spine loading increases in those individuals with LBP. A statistical model was developed that was able to describe 87% of the variability in compression, 61% in anteroposterior shear, and 65% in lateral shear. Conclusions. Those patients with greater kinematic compromise used higher levels of antagonistic muscle coactivation that not only reduced trunk motion but also resulted in increases in spine loading. Given the degree of kinematic compromise and the lifting task conditions, a method has been devised to predict the increase in spine loading above and beyond that of an asymptomatic individual when performing typical materials handling tasks. Sixty-two patients with low back pain and 61 who were asymptomatic were evaluated for signs of kinematic compromise during a prelift test. All subjects were then asked to perform a variety of lifting exertions that varied in lift origin, lift asymmetry position, and weight lifted. A model was able to predict increases in spine loading from the trunk kinematic compromise.
The rapidly growing number of home healthcare workers (HHCW) are exposed to unique occupational hazards within each patient home. This article describes the development of an observation tool to document occupational hazards HHCWs encounter.Tool development followed three steps: determining content domain, content validity, and inter-rater agreement.Expert feedback guided the revision of content domain to 636 items. Scale level content validity index (S-CVI) was 0.90. Inter-rater agreement tests resulted in percent agreement and accuracy mean of 89.5% and frequency variables resulted in standard deviations from 0 to 8.62.The observation tool encompasses the diverse range of occupational hazards HHCWs encounter; inter-rater percent agreement and overall accuracy scores were acceptable. Future pilot testing of this tool among broader raters and populations is recommended to characterize its usability, internal consistency, and reliability to assess HHCW occupational hazards.
A study was performed to investigate how different types of handle coupling affect the loading on the spine. Ten male grocery item selectors performed a laboratory simulation of a warehouse palletizing task. Participants transferred the cases from a pallet in a storage bin to the destination pallet. The trunk motions and muscle activities were monitored by a Lumbar Motion Monitor (LMM) and electromyographic electrodes, respectively, and used as input to an EMG-assisted biomechanical model. The results of the study revealed that the presence of handles reduced the complex loads on the spine. This was particuarly true when lifting to the lowest positions of the pallet, where the highest forces occurred. It was determined that the maximum spinal compression forces were reduced by an average of 6.8% when handles were added to the cases. The presence of handles affected the moments imposed on the trunk in the lower regions on the pallet, indicating a difference in lifting style and/or more sagittal flexion. The results of this study suggest that the multiplier for handle coupling in the 1991 NIOSH Revised Lifting Equation was appropriate for higher lifts (at 133.8 cm), but needs to be more protective for 'poor' coupling conditions with lower vertical heights, which are the most common in industry. Based on these results, it is recommended that handles be designed into the cases that are commonly lifted from low levels in warehousing and other manual materials handling situations.
