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In order to advance lithium-ion battery technologies, particularly fast charging abilities, it is important to understand the non-equilibrium processes occurring in functioning materials under realistic conditions, in real time, and on the nano- to meso-scale. Currently, operando imaging of lithium-ion dynamics requires sophisticated synchrotron X-ray or electron microscopy methods. These techniques do not lend themselves to high-throughput material screening, and often fail to capture the behaviour of individual particles in batteries charging faster than 2C. In this work, we introduce a laboratory-based optical interferometric scattering microscope to resolve lithium-ion transport in battery materials at the single-particle level, and apply it to follow rapid cycling of the archetypical cathode material Li x CoO2. We directly visualise the insulator-metal, solid solution and lithium ordering phase transitions and determine rates of lithium insertion and removal from individual particles, identifying different mechanisms on charge vs. discharge. Finally, we capture the real-time formation of domain boundaries between different crystal orientations associated with the monoclinic lattice distortion at Li0.5CoO2. The high throughput nature of our methodology allows many particles to be sampled across the electrode and enables exploration of the role of defects, morphologies and cycling rate on battery degradation. The imaging concept is general and may be applied to study any active electrode material, and more broadly, any system where the transport of ions is associated with electronic or structural changes. Due to its straightforward lab-based implementation, we hope that this methodology will become an indispensable tool for high-throughput material discovery and mechanistic studies, to complement existing synchrotron-based methodologies. References Merryweather, A.J., Schnedermann, C., Jacquet, Q. et al. Operando optical tracking of single-particle ion dynamics in batteries. Nature 594, 522–528 (2021).

Sex, head and neck posture, and cervical muscle preparation are contributing factors in the severity of head and neck injuries. However, it is unknown how these factors modulate the head kinematics. In this study, twenty-four (16 male and 8 female) participants experienced 50 impulsive forces to their heads with and without an acoustic warning. Female participants demonstrated a 71 ms faster (p = 0.002) muscle activation onset compared to males after warning. The magnitude of muscle activation was not significant between sexes. Females exhibited 21% (p < 0.008) greater peak angular velocity in all force directions and 18% (p < 0.04) greater peak angular acceleration in sagittal plane compared to males. Females exhibited 15% (p = 0.03) greater peak linear acceleration compared to males only in sagittal flexion. Preparation attenuated head kinematics significantly (p < 0.03) in 11 out of 18 investigated head kinematics for both sexes. A warning eliciting a startle response 420 ms prior to the impact resulted in significant attenuation of all measured head kinematics in sagittal extension (p < 0.037). In conclusion, both sex and warning type were significant factors in head kinematics. These data provide insight into the complex relationship of muscle activation and sex, and may help identify innovative strategies to reduce head and neck injury risk in sports.

The Revised Strain Index (RSI), a model that quantifies physical exposure from individual hand/wrist exertions, tasks, and multi-task jobs, was used to quantify exposure for 1372 incident-eligible manufacturing, service and healthcare workers. Workers were followed for an average of 2.5 years (maximum 6 years) and had an average carpal tunnel syndrome (CTS) incidence rate of 4.6 per 100 person-years. Exceeding the a-priori RSI limit of 10.0 showed increased risk of CTS (Hazard Ratio (HR) = 1.45, 95% CI: 1.11-1.91, p = 0.01). There also was a dose-response relationship using proposed low (RSI ≤ 8.5, HR = 1.00), medium (HR = 1.42 (95% CI: 0.96-2.09, p = 0.08)), and high limits (RSI > 15, HR = 1.79 (95% CI: 1.19-2.69, p = 0.01), respectively. RSI as a continuous variable showed CTS risk increased steadily by between 1.9% and 3.3% per unit increase in RSI (p ≤ 0.03). These results suggest that the RSI is a useful tool for surveillance as well as for job intervention/design and continuous improvement processes.Practitioner Summary The Revised Strain Index (RSI) quantifies physical exposure from individual hand/wrist exertions, tasks, and multi-task jobs. Increased cumulative RSI scores (i.e. daily exposure score) are associated with increased risk of carpal tunnel syndrome (CTS). The RSI is potentially useful as a risk surveillance and intervention design tool.

Elderly patient falls are expensive and may cause serious harm. Studies have identified the sit-to-stand-and-walk (STSW) task as the task where the greatest number of elderly patient falls occur. There is a great need to identify the particular movement and environmental conditions that lead to these elderly patient falls. This study begins to address this gap by evaluating the elderly patient during self-selected hospital bed egress. Using an observed fall risk episode (FRE) as a fall proxy, statistically significant parameters were identified which include bed height, pausing prior to initiating gait, level of fall risk, and Stand phase. Low bed height was identified as the least safe bed height. Patient-specific bed height (PSBH) using the patient’s lower leg length (LLL) is recommended. In addition, suggested guidelines are presented for clinical application in setting PSBH without measuring the patient’s LLL.

Haptic terrain rendering is limited in existing Virtual Reality (VR) systems. This article describes integration of the Smart Shoe (SS) for physical terrain display with the TreadPort VR system. The SS renders both gross sloped terrain and subtle sensations of stepping on small objects or uneven surfaces. The TreadPort projects terrain on the floor and the SS renders terrain that the user steps upon via motion tracking. The research is motivated towards eventually providing gait training for people with Parkinson's Disease (PD), hence this work presents a pilot study evaluating haptic terrain rendering with healthy elderly and PD participants wearing the SS within the TreadPort. Uneven cobblestone surfaces are rendered by the SS as the participant steps on their graphical representation in VR. While posthoc analysis shows the study is underpowered, kinematic and spatiotemporal results derived from motion capture data demonstrates kinesthetic response (e.g., increased maximum ankle angle and minimum toe clearance, reduced minimum ankle angle and knee angle) provided by the SS. Questionnaire data shows increased VR realism and difficulty walking on cobbled terrain using SS rendering. Thus, results indicate that the integrated haptic system demonstrates promise in potential gait training for PD in future work.

Objective To examine differences in demographic, psychosocial, and job physical exposure risk factors between multiple low back pain (LBP) outcomes in a prospective cohort of industrial workers. Background LBP remains a leading cause of lost industrial productivity. Different case definitions involving pain (general LBP), medication use (M-LBP), seeking healthcare (H-LBP), and lost time (L-LBP) are often used to study LBP outcomes. However, the relationship between these outcomes remains unclear. Method Demographic, health status, psychosocial, and job physical exposure risk factors were quantified for 635 incident-eligible industrial workers. Incident cases of LBP outcomes and pain symptoms were quantified and compared across the four outcomes. Results Differences in age, gender, medical history, and LBP history were found between the four outcomes. Most incident-eligible workers (67%) suffered an LBP outcome during follow-up. Cases decreased from 420 for LBP (25.4 cases/100 person-years) to 303 for M-LBP (22.0 cases/100 person-years), to 151 for H-LBP (15.6 cases/100 person-years), and finally to 56 for L-LBP (8.7 cases/100 person-years). Conversely, pain intensity and duration increased from LBP to H-LBP. However, pain duration was relatively lower for L-LBP than for H-LBP. Conclusion Patterns of cases, pain intensity, and pain duration suggest the influence of the four outcomes. However, few differences in apparent risk factors were observed between the outcomes. Further research is needed to establish consistent case definitions. Application Knowledge of patterns between different LBP outcomes can improve interpretation of research and guide future research and intervention studies in industry.

Low back pain (LBP) is a common health problem and a major cause of lost productivity in workplaces. Manual materials handling (MMH) jobs have traditionally been regarded as risk factor for LBP. Compared to two-handed lifting, one-handed lifting has received little attention in both epidemiological and biomechanical research. In addition, one frequent complaint of the revised NIOSH lifting equation (RNLE) has been the lack of capability to directly evaluate one-handed lifting. Modifications have been proposed by the European Union, however their efficacy and influence have not yet been evaluated. This cross-sectional study provided objective survey of the MMH jobs, especially the one-handed lifting performed in manufacturing industry and investigated the outcomes of three proposed methods to address one-handed lifting using RNLE approach. Preliminary results suggest that workers with some one-handed lifting are associated with higher physical exposure. However, the increase was more significant among those who perform primarily one-handed lifting.

OBJECTIVE Assessment of possible relationships between work-related psychosocial measures and self-reported low back pain (LBP) outcomes in a large pooled dataset of 1929 participants from 82 facilities in the United States. METHODS Pooled data from three prospective cohort studies were used to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for relationships between psychosocial factors and the LBP outcomes. Personal and occupational confounders were controlled for in adjusted Logistic regression models. RESULTS Supervisor support and job satisfaction were significantly (P

Despite decades of research into patient falls, there is a dearth of evidence about how the design of patient rooms influences falls. Our multi-year study aims to better understand how patient room design can increase stability during ambulation, serving as a fall protection strategy for frail and/or elderly patients. The aim of this portion of the study was to ascertain the architect’s perspective on designing a room to mitigate the risk of falls, as well as to evaluate the face validity of a predictive algorithm to assess risk in room design using the input of a design advisory council (AC). The purpose of this paper is to provide insight into the design process and decision-making for patient rooms, summarize the impressions of industry experts about the configurations and layout of the patient rooms tested in a preliminary augmented reality model, establish the face validity of modeled heat maps depicting risk, and report the results of a pre-meeting and post-meeting survey of expert opinions. Feedback was coded using human factors/ergonomic (HF/E) design principles, and the findings will be used to guide further development of an “optimal” prototype room for human subject testing. The results confirm the challenges that architects face as they balance competing priorities and reveal how a participatory process focusing on preventing falls can shift assumptions about design strategies, especially subtle changes (e.g., toilet orientation).

High-pressure level and sudden sound, especially during an elevated state of alertness can elicit a startle response. Startle response can induce sudden, intense muscle activations. Some studies have shown that increasing neck muscle activation during impact situations can reduce the risk of concussion and neck injury. This research aimed to study muscle coactivation patterns, contraction latency and the level of muscle activation in startle response compared to the voluntary response. To achieve this goal, a testbed capable of applying impacts to the head in four directions was created. Auditory (115 dB) startle stimulus was delivered and muscle activation measured using sEMG on neck muscles during startle and voluntary responses. We investigated a 1000 ms time period starting at the time that the sound is played to the time at impact. Results indicate that the first muscle activation in startle response is 2.1 times higher, 5.9 times faster and involved more muscles than in a voluntary response.

To quantify sensitivity and specificity of the tender points and demonstrate how variability in case definition impacts prevalence of lateral epicondylitis (LE).Baseline data analyzed from 1216 workers from the WISTAH study, a multicenter prospective cohort study of upper extremity musculoskeletal disorders. All workers completed computerized questionnaires, structured interviews, and two independent physical examinations in accordance with an established protocol.The prevalence of LE differed based on case definition ranging from 4.7% to 12.1%. Sensitivity was low for tender points 1 to 4 ranging from 6.8% to 34.6%. Specificity was high for tender points 1 to 4 ranging from 95.2% to 97.9%.The prevalence of lateral epicondylitis differs markedly based on case definition used, ranging more than two-fold. Standardization of a case definition is essential to allow for comparisons across studies.

Background Detailed information regarding workers who experience an amputation in the workplace over the last decade is limited. To better understand the financial and functional impact of a work‐related amputation, this study quantifies the incidence of work‐related amputations in the California workforce from 2007 to 2018 as well as the relationship between medical costs and lost workdays as a function of amputation level. Methods Workers' compensation claims data from California spanning the years 2007 to 2018 were evaluated to describe trends in amputation incidence (N = 16 931). Quartile values for medical costs, indemnity costs, and lost workdays were reported as a function of amputation level. Correlations were performed between medical costs and lost workdays to examine their relationship. Results The average incidence from 2007 to 2018 was 8.9 (95% CI 8.5, 9.4) amputations per 100 000 workers. There was a significant spike in amputations in 2008. Partial‐hand amputations were the most common with 73.3 (95% CI 69.2, 77.7) cases per 1 000 000 workers, and the industry with the highest incidence was construction with 26.0 (95% CI 22.4, 30.0) cases per 100 000 workers. Overall, medical costs were moderately correlated with lost workdays (Spearman's rho = 0.51), and that level of correlation remained relatively consistent across all levels of amputation (Spearman's rho = 0.48‐0.62). Conclusions Amputations represent high medical costs and number of lost workdays. Considering the type of amputation and the industry the injury occurred in is important in order to work toward returning this population to work. Our results present the status of amputations in the California workplace and establish a basis for using medical costs to infer lost work productivity for this population.

Background: For Dietetics students, starting university means developing the knowledge and skills required to be a healthcare practitioner. This pilot study aimed to explore the perceptions and views of the students on their drivers and barriers of healthy eating while studying Dietetics at university. Methods: A qualitative study was undertaken with a purposive sample of six final year Dietetic students at a UK university. Semi-structured in-depth interviews were used to elicit students’ experiences and perceptions of barriers to healthy eating. Interview data were analysed thematically. Results: Five themes emerged from the interview data including studying Dietetics, placement, influence of significant others, food security, and social and cultural aspects of the university life, with several sub-themes, and perspectives about the future beyond the university life. Conclusions: The findings suggest a potential need for Dietetics course providers to consider the range of barriers to healthy eating that students may encounter whilst studying and how these may undermine their ability to develop healthy eating practices and effective professional skills. Further research is required that explores the extent of barriers to healthy eating and examine whether these impinge upon effective practice.

Objectives: This study proposes a computational model to evaluate patient room design layout and features that contribute to patient stability and mitigate the risk of fall. Background: While common fall risk assessment tools in nursing have an acceptable level of sensitivity and specificity, they focus on intrinsic factors and medications, making risk assessment limited in terms of how the physical environment contributes to fall risk. Methods: We use literature to inform a computational model (algorithm) to define the relationship between these factors and the risk of fall. We use a trajectory optimization approach for patient motion prediction. Results: Based on available data, the algorithm includes static factors of lighting, flooring, supportive objects, and bathroom doors and dynamic factors of patient movement. This preliminary model was tested using four room designs as examples of typical room configurations. Results show the capabilities of the proposed model to identify the risk associated with different room layouts and features. Conclusions: This innovative approach to room design evaluation and resulting estimation of patient fall risk show promise as a proactive evidence-based tool to evaluate the relationship of potential fall risk and room design. The development of the model highlights the challenge of heterogeneity in factors and reporting found in the studies of patient falls, which hinder our understanding of the role of the built environment in mitigating risk. A more comprehensive investigation comparing the model with actual patient falls data is needed to further refine model development.

Mild traumatic brain injury (mTBI) and whiplash-associated disorder are the most common head and neck injuries and result from a sudden head or body acceleration. The head and neck injury potential is correlated with the awareness, level of muscle activation, and posture changes at the time of the perturbation. Environmental acoustic stimuli or a warning system can influence muscle activation and posture during a head perturbation. In this study, different acoustic stimuli, including Non-Directional, Directional, and Startle, were provided 1000 ms before a head impact, and the amplitude and timing of cervical muscle electromyographic (EMG) data were characterized based on the type of warning. The startle warning resulted in 49% faster and 80% greater EMG amplitude compared to the Directional and Non-Directional warnings after warning and before the impact. The post-impact peak EMG amplitudes in Unwarned trials were lower by 18 and 21% in the retraction and rebound muscle groups, respectively, compared to any of the warned conditions. When there was no warning before the impact, the retraction and rebound muscle groups also reached their maximum activation 38 and 54 ms sooner, respectively, compared to the warned trials. Based on these results, the intensity and complexity of information that a warning sound carries change the muscle response before and after a head impact and has implications for injury potential.

The factors that contribute to the difficulties persons with Parkinson Disease (PwPD) have when negotiating transitions in walking surfaces are not completely known. The authors investigated if PwPD adjusted their step characteristics when negotiating a familiar outdoor surface transition between synthetic concrete and synthetic turf. Force plate and motion capture data were collected for 10 participants with mild to moderate Parkinson disease and 5 healthy older control participants ambulating bidirectionally across the transition between synthetic concrete and synthetic turf. Between groups, PwPD had a significantly higher minimum toe clearance (P = .007) for both directions of travel compared with the healthy control group. Within groups, PwPD significantly increased their hip (P P = .016) range of motion walking from concrete to turf, while the healthy control participants significantly increased their minimum toe clearance (P = .013), margin of stability (P = .019), hip (P P = .038) range of motion, and step length (P P = .014) and the healthy control group (P

Background Drywall installation has an injury rate four times that of the construction industry average. Workers are exposed to hazards related to slips, falls, and falling objects, in addition to the large and awkward loads they must carry. Drywall sheets can weigh more than 100 lb. and contribute to disabling musculoskeletal injuries of the shoulders and back. Objective In this study, an unpowered lift assist device was developed to manage the load of a drywall sheet during the installation process. Methods In order to measure the effect of the lift assist device, a laboratory study with 10 healthy male participants performing two lifts, lifting from ground to erect and lifting from erect to ceiling, with and without the help of the device, was performed. These lifts were chosen to simulate a drywall installer's frequent lifting motions. Participants were fitted with electromyography (EMG) on the erector spinae, latissimus dorsi, rectus abdominus, and external oblique muscles to measure activation. Mean, peak, and effort data for the lifting exercises were extracted and compared to the unassisted lift. Results The lift assist device resulted in a reduction in mean EMG signal of 69% average over both lifts and muscle groups. Peak EMG and effort (i.e., area under the curve) were reduced by 78% and 75%, respectively. Conclusions These data demonstrate the effectiveness of the device in reducing compressive back loads during drywall installation, which warrants future development.

Low back pain (LBP) is a common health problem and a major cause of lost productivity in workplaces. Lifting and lowering (LL) activities have traditionally been regarded as risk factor for LBP. In the literature, very little data have been reported describing industrial workers’ exposures to measured job physical demands using comprehensive and quantitative method, such as the revised NIOSH lifting equation (RNLE). This study pooled physical exposure data for the RNLE commonly collected in three independent LBP prospective studies. In total, over one million subtasks (i.e., lifting/lowering activities) were included in this pooled study. Examination of the pooled dataset revealed an increased data distribution of the physical job demands quantified by the RNLE. Research using the pooled dataset will improve the overall statistical power and help address the weaknesses identified in previous studies.

Objectives Slip, trip and fall (STFs) injuries are a significant problem in all industries, yet there are no significant prior reports assessing the relationship between occupational factors and STFs among home healthcare workers (HHCWs) who represent an ever increasing number of workers in the healthcare sector. The unpredictable nature of the work environment specific to HHCWs may lead to an increase in injuries from STFs. The purpose of this study was to quantify associations between occupational factors and STFs among HHCWs. Methods This cross-sectional study of 870 HHCWs assessed relationships between 12-month period prevalence of falls and occupational factors. Crude and adjusted odds ratios (OR) and 95% confidence intervals were calculated. Results Nearly 18% (N = 152) of HHCWs reported at least one fall in 12 months. Nurses were significantly more likely to have had a fall (OR = 3.33). Years worked in HHC, and near miss accidents were also related to falls. Patient care factors related to falls included feeling rushed or hurried, increasing number of patients, patient’s weight bearing status, combative patients, and issues of patient’s homes (e.g. dangerous animals, problems with access to beds or toilets). Conclusions Numerous work organizational and patient care factors are associated with increased risk of falls among HHCWs. Many of these are readily modifiable and should be a focus for intervention.

Background Persons with Parkinson's disease are at high risk for fall-related injuries with a large proportion of falls occurring while walking, especially when the walking environments are complex. The aim of this study was to characterize gait parameters on irregular surface for persons with Parkinson's disease. Methods Three-dimensional gait analysis was conducted for nine persons with Parkinson's disease and nine healthy age-matched adults on both regular and irregular surfaces. Repeated ANOVA and paired t-test were performed to determine the effect of surface and group for spatiotemporal, kinematic and stability variables. Findings Individuals with Parkinson's disease showed a larger ratio of reduction for speed, cadence and step length than controls when the surface changed from regular to irregular. The ankle transverse range of motion and root mean square of trunk acceleration increased on irregular surface for both groups. Additionally, individuals with Parkinson's disease demonstrated a decreased knee sagittal range of motion and trunk frontal and transverse range of motion compared with controls, especially on the irregular surface. Interpretation The irregular surface posed a greater challenge to maintain balance and stability for individuals with Parkinson's disease. A relatively small knee range of motion in the sagittal plane and large root mean square of trunk acceleration increased the potential fall risk for individuals with Parkinson's disease. This information improves the understanding of parkinsonian gait adaptations on irregular surfaces and may guide gait training and rehabilitation interventions for this high fall-risk population.

Background Gait impairments in people with Parkinson’s disease (PD) are accentuated in dual-task conditions. Most PD studies on dual-task gait have measured only straight line walking and treadmill gait. Gait alterations on irregular terrain are poorly understood. Research question To what extent does walking on irregular terrain exacerbate dual-task interference in people with PD, compared to age-matched control participants? Methods Gait data were collected for nine participants with mild to moderate PD and nine healthy age-matched participants on regular and irregular terrains. Gait was tested as a single task and in dual-task conditions with serial 7 subtractions. The spatiotemporal variables (speed, cadence, single limb support, step length and width), kinematic variables (range of motion for hip, knee and ankle joints) and stability variables (trunk range of motion and center of mass acceleration RMS) were compared across conditions. Results People with PD showed reduced gait speed and cadence and increased mediolateral center of mass acceleration when walking on irregular terrain with dual-tasks. Surface irregularity was associated with increased ankle transverse motion in both groups. Increased hip and knee sagittal motion was observed in the control participants when terrain changed from regular to irregular under dual-task conditions. This was not statistically significant for the PD group. Significance Dual-task walking on irregular terrain exacerbated the gait deficits, particularly for people with PD. Gait speed, cadence and mediolateral body stability were compromised when people with PD walked on irregular terrain whilst performing dual-tasks. There was an increase in ankle transverse motion in both groups when traversing irregular terrain. This might have been an adaptive strategy, to prevent tripping.

Concerns surrounding concussions from impacts to the head necessitate research to generate new knowledge about ways to prevent them and reduce risk. In this paper, we report the relative temporal characteristics of the head resulting from neck muscle co-contraction and postural changes following a sudden force applied to the head in four different directions. In the two “prepared” conditions (i.e., co-contraction and postural), participants experienced impulsive forces to the head after hearing a warning. The warning given for the postural condition informed both the direction and timing of the impulsive force. Participants responded to the postural warning by altering their head posture, whereas in the co-contraction warning, the force direction was unknown to them, and they were asked to isometrically co-contract their neck muscles after the warning. Peak angular velocity reduced by 29% in sagittal extension, 18% in sagittal flexion, and 23% in coronal lateral flexion in prepared vs. unwarned conditions. Peak linear acceleration was attenuated by 15% in sagittal extension, 8% in sagittal flexion, and 18% in coronal lateral flexion in prepared vs. unwarned conditions. Changes in peak angular acceleration were not uniform. We also measured a significant delay in the peak angular velocity (22 vs. 44.8 ms) and peak angular acceleration (7 vs. 20 ms) after peak linear acceleration in prepared compared to unwarned conditions. An increase in muscle activation significantly reduced the peak angular velocity and linear acceleration. Gross head movement was significantly decreased with preparation. These findings suggest that a warning prior to impact can reduce head kinematics associated with injury.

The Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value for hand activity level (TLV for HAL) have been shown to be associated with prevalence of distal upper-limb musculoskeletal disorders such as carpal tunnel syndrome (CTS). The SI and TLV for HAL disagree on more than half of task exposure classifications. Similarly, time-weighted average (TWA), peak, and typical exposure techniques used to quantity physical exposure from multi-task jobs have shown between-technique agreement ranging from 61% to 93%, depending upon whether the SI or TLV for HAL model was used. This study compared exposure-response relationships between each model-technique combination and prevalence of CTS. Physical exposure data from 1,834 workers (710 with multi-task jobs) were analyzed using the SI and TLV for HAL and the TWA, typical, and peak multi-task job exposure techniques. Additionally, exposure classifications from the SI and TLV for HAL were combined into a single measure and evaluated. Prevalent CTS cases were identified using symptoms and nerve-conduction studies. Mixed effects logistic regression was used to quantify exposure-response relationships between categorized (i.e., low, medium, and high) physical exposure and CTS prevalence for all model-technique combinations, and for multi-task workers, mono-task workers, and all workers combined. Except for TWA TLV for HAL, all model-technique combinations showed monotonic increases in risk of CTS with increased physical exposure. The combined-models approach showed stronger association than the SI or TLV for HAL for multi-task workers. Despite differences in exposure classifications, nearly all model-technique combinations showed exposure-response relationships with prevalence of CTS for the combined sample of mono-task and multi-task workers. Both the TLV for HAL and the SI, with the TWA or typical techniques, appear useful for epidemiological studies and surveillance. However, the utility of TWA, typical, and peak techniques for job design and intervention is dubious.

Introduction Previous studies have reported higher wrist ratios (WR) related to carpal tunnel syndrome (CTS) but have not assessed effect modification by obesity and may have inadequately controlled for confounders. Methods Baseline data of a multicenter prospective cohort study were analyzed. CTS was defined by nerve conduction study (NCS) criteria and symptoms. Results Among the 1,206 participants, a square-shaped wrist was associated with CTS after controlling for confounders (prevalence ratio = 2.27; 95% confidence interval [95% CI], 1.33–3.86). Body mass index (BMI) was a strong effect modifier on the relationship between WR and both CTS and abnormal NCS results, with normal weight strata of rectangular versus square wrists = 8.18 (95% CI, 1.63–49.96) and 7.12 (95% CI, 2.19–23.16), respectively. Discussion A square wrist is significantly associated with CTS after controlling for confounders. Effect modification by high BMI masked the eightfold magnitude adjusted relationship seen between WR and CTS among normal weight participants. Muscle Nerve 56: 1047–1053, 2017

Outdoor recreation improves the quality of life for individuals with tetraplegia, however, a range of barriers exist in accessing these sports. This chapter describes the iterative design and field evaluation of the Tetra-Ski, a novel power-assisted ski chair for individuals who use a power wheelchair. Users control the Tetra-Ski with a joystick or sip-and-puff controller either independently or collaboratively with a tethered skier through a Shared-Control scheme. A field study of the Tetra-Ski demonstrated the usability of the system. The chapter also reflects on the Shared-Control approach to controlling Tetra-Ski, which effectively supported the unique abilities of different users. These findings inform the future application of this Shared-Control approach for use with other assistive technology and less-dependent forms of outdoor recreation. Finally, we describe some of the challenges we have faced developing and deploying a sports activity (skiing) for individuals with tetraplegia.

Background: Previously reported risk factors for common musculoskeletal disorders (MSDs) have been low in magnitude and with unclear pathophysiological mechanisms. Methods: Data from a nine-year prospective cohort were analyzed. Baseline data included computerized questionnaires, structured interviews, physical examinations, anthropometric measurements, nerve conduction studies, and individualized measurement of job physical factors. Framingham risk scores were calculated. A priori case definitions were constructed for carpal tunnel syndrome, lateral epicondylopathy, medial epicondylopathy, and rotator cuff tendinopathy. Monthly follow-ups were conducted to assess symptoms (development, resolution and/or treatments) and to perform physical examinations. Nerve conduction studies were performed every 6 months if any new-onset paresthesias in the prior six-month interval were reported. Results: The relative risk of four different MSDs increased with rising cardiovascular disease risk scores; adjusted relative risks for one or more MSD increased to 3.90 (95% CI, 2.20, 6.90) among those with 10-year cardiovascular risk scores above 15%. The relative risk of multiple MSDs increased more strongly with rising cardiovascular disease risk; adjusted relative risk for four or more MSDs increased to 17.40 (95% CI, 3.85, 78.62) among those with 10-year cardiovascular risk scores above 15%. Conclusions: Cardiovascular disease risk factors are strongly associated with the subsequent development of common MSDs. Risks among those with multiple MSDs are considerably stronger. Further investigations of this new potential line of prevention are needed, as well as the utility of these MSDs to identify the development of silent coronary artery disease. Funding Statement: This work was supported, in part, by grants from the National Institute for Occupational Safety and Health (NIOSH/CDC) grant 1R01OH010474–01 and NIOSH Education and Research Center training grant T42/CCT810426–10. Declaration of Interests: The authors declare that they have NO affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers’ bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript. Ethics Approval Statement: Institutional review boards of the University of Utah, University of Wisconsin-Milwaukee and Medical College of Wisconsin approved this study.

Simulating impacts to the head that are likely to cause concussion contributes knowledge to inform efforts to reduce head injury risk in sports. Previous studies used generic models and potentially missed subject-specific factors, which when combined with experimental data may offer additional insights about an individual’s risk. This study details methods for creating more subject-specific OpenSim models of the head and neck, which can be used in future studies to evaluate head injury risk during impacts. A generic model was scaled to match subject height and weight using data available from the literature. Muscle strength and passive properties were also scaled in order to reproduce experimental data obtained during safe impacts to the head. The average error between experimental and simulation kinematic values was under 15% for all but one of the subject-models. By applying the methods presented in this study, future work could include using subject-specific models to assess individual athletes and generate personalized training protocols to help prevent injury. Future work could also include subject-specific models to investigate the effects of posture, startle response, and auditory warnings on head injury metrics.

OBJECTIVE: The primary goal of this cross-sectional analysis was to determine the relationships between self-reported low back pain (LBP) ratings and use of opioid medications. METHODS: At baseline, subjects completed a computerized questionnaire. Structured interviews were conducted by residents or certified therapists under the direction of board-certified physicians. RESULTS: There was a statistically significant non-linear relationship between lifetime prevalence of worst LBP rating (0–10) and lifetime prevalence of opioid use. Those with a low pain rating for worst lifetime LBP and those with high LBP ratings were significantly more likely to have been prescribed opioids. Surprisingly, those with moderate pain ratings were the least likely to have used opioids. CONCLUSIONS: This study found a higher use of opioids between workers with low and high severe pain rating then those with moderate pain. We also found an increase of opioid use for severe pain.

Decoding motor user intent using electroencephalography (EEG) sensors may aid individuals with limited upper extremity mobility. Researchers have successfully used Filter Bank Common Spatial Pattern (FBCSP) and Linear Discriminant Analysis (LDA) to predict user intent from EEG. Frequency bands between 8 to 40 Hz, with 4 Hz intervals are used as inputs to FBCSP classification. While this range includes the commonly used alpha (8–13 Hz) and beta (16–24 Hz) frequency bands, it excludes the delta band (0.3–3 Hz). The delta band has been shown to contain information regarding user intent. This paper investigates the accuracy of predicting user intent to reach and lift when modifying FBCSP to include combinations of alpha, beta and delta bands. This comparison was performed for clinical (32-electrodes) and commercial (12-electrodes) EEG electrode configurations using the WAY-EEG-GAL dataset. The simulated commercial configuration placement mimicked those from the Emotiv Epoc+. We predicted intent to reach (HandStart) and lift a block (LiftOff) by comparing the EEG signal to rest conditions. Intent classification accuracy is the accuracy to predict the future event before the event occurs. Maximum classification accuracy is the maximum accuracy to predict the event during the region of interest (−2.5, −2.0 sec.). Intent classification accuracy of 80.2% and 76.7% were achieved for the clinical and commercial configurations, respectively. Maximum classification accuracy of 85.9% and 83.0% were achieved for the clinical and commercial configuration, respectively. The combination of all three bands outperformed alpha-beta-only and delta-only by 0.9% and 9.9% for the clinical and 4.0% and 4.3% for the commercial for maximum classification accuracy. Using the combination of bands resulted in a maximum classification above 80% for the commercial configuration. These results suggest that including the delta frequency band can help improve the accuracy of user intent in clinical and commercial headsets.

Identify if Carpal tunnel syndrome (CTS) symptoms vary by measured biomechanical exposures.A nested prospective cohort within a large, multicenter, 8-year cohort study. The CTS case definition was tingling/numbness in 2+ median nerve-served digits plus a nerve conduction study consistent with CTS. Workers were assigned to: (1) low (strain index [SI] less than or equal to 6.1), and (2) high (SI more than 6.1) job groups.Among 1201 workers, 106 had CTS. Those in the high SI group became and remained symptom-free for at least 3 months, faster than the low SI group, adjusted hazard ratio (HR) = 2.07 (95% confidence interval [CI] = 1.21 to 3.56, P = 0.008). Only surgical release trended towards resolving CTS. Light duty had no impact, and job change was associated with delayed symptoms resolution.High biomechanical exposures paradoxically predicted faster improvement in CTS and light duty did not result in symptom resolution.

The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors. The results revealed that kneepad design can significantly modify the forces on the knee joint through redistribution. The Professional Gel design was preferred among the five tested kneepads which was confirmed with both force measurements and participants' responses. The extreme reaching locations induced significantly higher joint forces on left knee or right knee depending on task. The conclusion of this study is that a properly selected kneepad for specific tasks and a more neutral working posture can modify the force distribution on the knees and likely decrease the risk of knee disorders from kneeling work.

The paper presents a novel approach involving the use of Maxwell relations to combine multiple physiological measures to provide a measure of entropy change. The physiological measures included blood pressure (BP), heart rate (HR), skin temperature (ST), electromyogram (EMG), and electrodermal response (EDR). The multiple time-series physiological data were collected from eight subjects in an experimental pilot study conducted at the Human Engineering Laboratory of NASA Langley Research Center. The methodology included data collection during a relaxation period of eighteen minutes followed by a sixty-minute cognitive task. Two types of entropy change were computed: (a) entropy change (ΔSBP) due to blood pressure, heart rate, and skin temperature and (b) entropy change (ΔSEMG) due to electromyogram, electrodermal response, and skin temperature. The results demonstrate that entropy change provides a valuable composite measure of individual physiological response to various stressors that could be valuable in the areas of medical research, diagnosis, and clinical practice.

Although a significant proportion of patient falls occur during egress from the hospital bed, the biomechanical adaptations during egress from different bed heights are still largely unknown. The purpose of this study was to evaluate the effect of hospital bed height on natural transition during egress in patients with Parkinson disease (PD). Twelve patients with PD and fourteen healthy elderly adults (HEA) were recruited and the natural transition during egress from three different bed heights (low, medium and high) were recorded for each participant using a motion capture system and force plates. The bed egress time, joint kinematics, ground reaction force and center of mass (CoM) were compared using a two-factor repeated ANOVA to determine the effects of three bed heights and two groups. The results showed that patients with PD had a significantly increased bed egress time, decreased peak of pelvis anterior tilt, hip flexion, and anteroposterior distance between pelvis center and CoM compared to HEA. Additionally, both PD and HEA groups increased the peak of trunk, hip and knee flexions to generate forward CoM momentum and joint torque to rise from a low bed height. These findings indicated that patients with PD invoked a more conservative movement pattern than HEA during egress to improve postural stability. The low bed height increased demands of balance and postural control during egress which exacerbates the risk of falls for patients with PD.

Head injuries frequently occur in American football and other contact sports. Uncertainty on the effects of cervical muscle properties on head injury risk may be due to the limitations of previous observational studies. This simulation study employs a musculoskeletal model of the head and neck to investigate the effect of several factors related to head injury metrics in American Football. These factors include isometric muscle strength, the eccentric multiplier (which is related to the athlete's ability to apply greater muscle force during eccentric contractions), posture, muscle activation patterns, and impact properties. Impact properties were based on the literature and tuned to reproduce peak linear and rotational accelerations of the skull. We hypothesized that active neck muscles significantly reduce head injury metrics. We systematically altered each model parameter to test our hypothesis. We then determined which model parameters affect head injury metrics the most. The results of this study indicate that active neck muscles have a statistically significant effect on head injury metrics. Increasing muscle strength and eccentric multiplier also resulted in a statistically significant reduction of head injury metrics. However, posture prior to impact had a much stronger effect than any other factor on head injury metrics. A comprehensive approach to athlete training protocols is recommended, including exercises aimed at increasing eccentric muscle strength and preparation for impacts. Future studies should investigate how targeted muscle strengthening and impact training (i.e. activation patterns and posture) modifies risk.

One of the most concerning and costly problems in hospitals is patients falls. We address this problem by introducing PAM, a patient assistant mobile robot, that maneuvers mobility aids to assist with fall prevention. Common objects found inside hospitals include objects with legs (i.e. walkers, tables, chairs, equipment stands). For a mobile robot operating in such environments, safely maneuvering these objects without collision is essential. Since providing the robot with dynamic models of all possible legged objects that may exist in such environments is not feasible, autonomous learning of an approximate dynamic model for these objects would significantly improve manipulation planning. We describe a probabilistic method to do this by fitting pre-categorized object models learned from minimal force and motion interactions with an object. In addition, we account for multiple manipulation strategies, which requires a hybrid control system comprised of discrete grasps on legs and continuous applied forces. To do this, we use a simple one-wheel point-mass model. A hybrid MPC-based manipulation planning algorithm was developed to compensate for modeling errors. While the proposed algorithm applies to a broad range of legged objects, we only show results for the case of a 2-wheel, 4-legged walker in this paper. Simulation and experimental tests show that the obtained dynamic model is sufficiently accurate for safe and collision-free manipulation. When combined with the proposed manipulation planning algorithm, the robot can successfully move the object to a desired position without collision.

Rapid Upper Limb Assessment (RULA) is a posture driven ergonomic risk assessment method. The RULA is simple to apply, but consequently has substantial limitations because of limited force and joint angle resolutions. Using OpenSim to understand soft tissue loading and inertial measurement units (IMUs) to measure posture represents a novel approach and provides greater resolution. We simulated the upper limb in multiple postures and under various loading conditions using OpenSim. We compared five OpenSim model output metrics to RULA risk scores. Total joint reaction forces aligned best with RULA scores. Future work will incorporate IMUs, more simulations, and analyze longitudinal injury data to model and estimate ergonomic risk.

Diagnostic screening tests for carpal tunnel syndrome (CTS) have not been rigorously assessed in large populations.This study is a cross-sectional analysis from a prospective cohort study. Participants' (n = 1,194) symptoms and disease prevalence were measured. Sensitivity, specificity, and positive and negative predictive values (NPVs) were calculated.When defining CTS as tingling/numbness in at least two median nerve-served digits and an abnormal median nerve conduction study, the prevalence was 8.9%. The sensitivity of paresthesias with nocturnal awakening was 77.4%. The sensitivity of the Phalen sign was 52.8% and that of the Hoffman-Tinel sign was only 37.7%.The highest sensitivity (77.4%) for a case definition of CTS in this population of workers was for nocturnal tingling/numbness in a median nerve distribution, and the highest specificity (97.5%) was for continuous tingling/numbness. The Phalen sign has a sensitivity of 52.8% and NPV of 95%, suggesting that the NPV is of particular diagnostic value. Hoffman-Tinel signs seem primarily helpful for the NPV (93.7%).Level II diagnostic study.

Background Low back pain (LBP) is a common and costly problem throughout the United States. To achieve a greater understanding of the occupational risk factors, the National Institute for Occupational Safety and Health (NIOSH) funded a low back health effects consortium, which performed several surveillance studies throughout the United States. This study combines data from the consortium research groups resulting in a data set with nearly 2000 workers in various regions of the country. The purpose of this paper is to examine prevalence and personal risk factors of low back health effects among these workers. Methods There were three common questions regarding history of low back health effects in the past 12 months including 1) have you had LBP lasting 7 days, 2) have you sought medical care for LBP, and 3) have you taken time off work due to LBP. The questionnaire included demographic questions. There were five data collections institutions or sites including NIOSH, Ohio State University, University of Wisconsin-Milwaukee, Texas A&M University, and University of Utah. Results The 12-month period prevalence of low back pain lasting 7 days, seeking medical care, and lost time due to LBP were 25, 14 and 10%, respectively. There were no statistically significant differences in gender, age or weight between cases and non-cases for any prevalence measure. The height of workers was significantly greater in the cases compared to non-cases for all three prevalence definitions. There were significant differences among the sites on the prevalence of seeking medical care for LBP and lost time due to LBP. The Ohio State University had significantly higher prevalence rates for seeking medical care and lost time due to LBP than University of Wisconsin, University of Utah, or Texas A&M University. Conclusion LBP, the least severe low back health effect studied, had the highest prevalence (25%) and lost time due to LBP, the most severe low back health effect studied, had the lowest prevalence (10%) among nearly 2000 US manual material handling workers. There was a significant site or regional influence in prevalence rates for seeking medical care and lost time due to LBP.

Introduction: There is a growing body of research connecting musculoskeletal diseases to both job physical exposures and psychosocial exposures. Associations between job physical exposures and psychosocial factors have not been well studied or measured. These exploratory analyses evaluate relationships between quantified exposures and psychosocial outcomes. Methods: Personalized measures of duration, repetition, force and composite scores of the Strain Index (SI) and the Threshold Limit Value for Hand Activity Level (TLV for HAL) were compared to 10 psychosocial measures. Associations and predicted probabilities were evaluated using ordered logistic regression. Results and Discussion: Among 1834 study participants there were numerous significant relationships. Overall, as job physical exposures increased, psychosocial measures worsened. However, both general health and mental exhaustion improved with higher job exposures. Depression was most strongly related with higher repetition, while physical exhaustion was most strongly related with higher force. SI and TLV for HAL were significantly related to numerous psychosocial factors. Relationships remained after adjustment for confounders of age, BMI and gender. Conclusion: This study measured multiple associations between job physical exposures and both occupational and non-occupational psychosocial factors. Further research is needed to quantify the impacts on occupational health outcomes.

The relationships between work organisational, biomechanical and psychosocial factors were studied using cross-sectional data from a pooled dataset of 1834 participants. The work organisational factors included: job rotation, overtime work, having second jobs and work pace. Task and job level biomechanical variables were obtained through sub-task data collected in the field or analysed in the laboratory. Psychosocial variables were collected based on responses to 10 questions. The results showed that job rotations had significant effects on all biomechanical and most psychosocial measures. Those with job rotations generally had higher job biomechanical stressors, and lower job satisfaction. Overtime work was associated with higher job biomechanical stressors, and possibly self-reported physical exhaustion. Those having second jobs reported getting along with co-workers well. Work pace had significant influences on all biomechanical stressors, but its impact on job biomechanical stressors and psychosocial effects are complicated.The findings are based on a large number of subjects collected by three research teams in diverse US workplaces. Job rotation practices used in many workplaces may not be effective in reducing job biomechanical stressors for work-related musculoskeletal disorders. Overtime work is also associated with higher biomechanical stressors.

The Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value for Hand Activity Level (TLV for HAL) use different constituent variables to quantify task physical exposures. Similarly, time-weighted-average (TWA), Peak, and Typical exposure techniques to quantify physical exposure from multi-task jobs make different assumptions about each task's contribution to the whole job exposure. Thus, task and job physical exposure classifications differ depending upon which model and technique are used for quantification. This study examines exposure classification agreement, disagreement, correlation, and magnitude of classification differences between these models and techniques.Data from 710 multi-task job workers performing 3,647 tasks were analyzed using the SI and TLV for HAL models, as well as with the TWA, Typical and Peak job exposure techniques. Physical exposures were classified as low, medium, and high using each model's recommended, or a priori limits. Exposure classification agreement and disagreement between models (SI, TLV for HAL) and between job exposure techniques (TWA, Typical, Peak) were described and analyzed.Regardless of technique, the SI classified more tasks as high exposure than the TLV for HAL, and the TLV for HAL classified more tasks as low exposure. The models agreed on 48.5% of task classifications (kappa = 0.28) with 15.5% of disagreement between low and high exposure categories. Between-technique (i.e., TWA, Typical, Peak) agreement ranged from 61-93% (kappa: 0.16-0.92) depending on whether the SI or TLV for HAL was used.There was disagreement between the SI and TLV for HAL and between the TWA, Typical and Peak techniques. Disagreement creates uncertainty for job design, job analysis, risk assessments, and developing interventions. Task exposure classifications from the SI and TLV for HAL might complement each other. However, TWA, Typical, and Peak job exposure techniques all have limitations. Part II of this article examines whether the observed differences between these models and techniques produce different exposure-response relationships for predicting prevalence of carpal tunnel syndrome.

Background WHO and UNICEF have proposed an action plan to achieve universal water, sanitation and hygiene (WASH) coverage in healthcare facilities (HCFs) by 2030. The WASH targets and indicators for HCFs include: an improved water source on the premises accessible to all users, basic sanitation facilities, a hand washing facility with soap and water at all sanitation facilities and patient care areas. To establish viable targets for WASH in HCFs, investigation beyond ‘access’ is needed to address the state of WASH infrastructure and service provision. Patient and caregiver use of WASH services is largely unaddressed in previous studies despite being critical for infection control. Methods The state of WASH services used by staff, patients and caregivers was assessed in 17 rural HCFs in Rwanda. Site selection was non-random and predicated upon piped water and power supply. Direct observation and semi-structured interviews assessed drinking water treatment, presence and condition of sanitation facilities, provision of soap and water, and WASH-related maintenance and record keeping. Samples were collected from water sources and treated drinking water containers and analyzed for total coliforms, E. coli, and chlorine residual. Results Drinking water treatment was reported at 15 of 17 sites. Three of 18 drinking water samples collected met the WHO guideline for free chlorine residual of >0.2 mg/l, 6 of 16 drinking water samples analyzed for total coliforms met the WHO guideline of

Many factors can affect a surgeon's performance in the operating room; these may include surgeon comfort, ergonomics of tool handle design, and fatigue. A laparoscopic tool handle designed with ergonomic considerations (pistol grip) was tested against a current market tool with a traditional pinch grip handle. The goal of this study is to quantify the impact ergonomic design considerations which have on surgeon performance. We hypothesized that there will be measurable differences between the efficiency while performing FLS surgical trainer tasks when using both tool handle designs in three categories: time to completion, technical skill, and subjective user ratings.The pistol grip incorporates an ergonomic interface intended to reduce contact stress points on the hand and fingers, promote a more neutral operating wrist posture, and reduce hand tremor and fatigue. The traditional pinch grip is a laparoscopic tool developed by Stryker Inc. widely used during minimal invasive surgery. Twenty-three (13 M, 10 F) participants with no existing upper extremity musculoskeletal disorders or experience performing laparoscopic procedures were selected to perform in this study. During a training session prior to testing, participants performed practice trials in a SAGES FLS trainer with both tools. During data collection, participants performed three evaluation tasks using both handle designs (order was randomized, and each trial completed three times). The tasks consisted of FLS peg transfer, cutting, and suturing tasks.Feedback from test participants indicated that they significantly preferred the ergonomic pistol grip in every category (p0.05); most notably, participants experienced greater degrees of discomfort in their hands after using the pinch grip tool. Furthermore, participants completed cutting and peg transfer tasks in a shorter time duration (p0.05) with the pistol grip than with the pinch grip design; there was no significant difference between completion times for the suturing task. Finally, there was no significant interaction between tool type and errors made during trials.There was a significant preference for as well as lower pain experienced during use of the pistol grip tool as seen from the survey feedback. Both evaluation tasks (cutting and peg transfer) were also completed significantly faster with the pistol grip tool. Finally, due to the high degree of variability in the error data, it was not possible to draw any meaningful conclusions about the effect of tool design on the number or degree of errors made.