Inter- and intra- observer reliability of risk assessment of repetitive work without an explicit method

Consistency between the ACGIH TLV for hand activity and proposed action levels for wrist velocity and forearm muscular load based on objective measurements: an example from the assembly industry

Objectives. This study aimed to investigate the consistency between results of the American Conference for Governmental Occupational Hygienists (ACGIH) threshold limit value (TLV) for hand activity and proposed action levels of objective measurements in risk assessments of work-related musculoskeletal disorders. Methods. Wrist velocities and forearm muscular load were measured for 11 assemblers during one working day. Simultaneously, each assembler's hand activity level (HAL) during three sub-cycles was rated twice on two separate occasions by two experts, using a HAL scale. Arm/hand exertion was also rated by the assemblers themselves using a Borg scale. In total, 66 sub-cycles were assessed and assigned to three exposure categories: A) below ACGIH action limit (AL) (green); B) between AL and TLV (yellow); and C) above TLV (red). The median wrist velocity and the 90th percentile of forearm muscular load obtained from the objective measurements corresponding to the sub-cycles were calculated and assigned to two exposure categories: A) below or C) above the proposed action level. Results. The agreement between ACGIH TLV for hand activity and the proposed action level for wrist velocity was 87%. Conclusions. The proposed action level for wrist velocity is highly consistent with the TLV. Additional studies are needed to confirm the results.

A Rapid Review on the Effectiveness and Use of Wearable Biofeedback Motion Capture Systems in Ergonomics to Mitigate Adverse Postures and Movements of the Upper Body

Work-related diseases and disorders remain a significant global health concern, necessitating multifaceted measures for mitigation. One potential measure is work technique training utilizing augmented feedback through wearable motion capture systems. However, there exists a research gap regarding its current effectiveness in both real work environments and controlled settings, as well as its ability to reduce postural exposure and retention effects over short, medium, and long durations. A rapid review was conducted, utilizing two databases and three previous literature reviews to identify relevant studies published within the last twenty years, including recent literature up to the end of 2023. Sixteen studies met the inclusion criteria, of which 14 were of high or moderate quality. These studies were summarized descriptively, and the strength of evidence was assessed. Among the included studies, six were rated as high quality, while eight were considered moderate quality. Notably, the reporting of participation rates, blinding of assessors, and a-priori power calculations were infrequently performed. Four studies were conducted in real work environments, while ten were conducted in controlled settings. Vibration feedback was the most common feedback type utilized (n = 9), followed by auditory (n = 7) and visual feedback (n = 1). All studies employed corrective feedback initiated by the system. In controlled environments, evidence regarding the effectiveness of augmented feedback from wearable motion capture systems to reduce postural exposure ranged from strong evidence to no evidence, depending on the time elapsed after feedback administration. Conversely, for studies conducted in real work environments, the evidence ranged from very limited evidence to no evidence. Future reach needs are identified and discussed.

Translation, cultural adaptation and assessment of psychometrics properties of the Extended Version of the Nordic Musculoskeletal Questionnaire (NMQ-E) in Persian language speaking people

BACKGROUND

To translate and cross-culturally adapt the Extended Version of the Nordic Musculoskeletal Questionnaire (NMQ-E) into Persian (NMQ-E-P) and evaluate the psychometric properties in a general population with different occupational tasks across nine body regions.

METHODS

This cross-sectional study was designed according to the standard guidelines and the COSMIN checklist. The NMQ-E-P was achieved through forward and backward translation methods and consensus to produce the final draft. A Persian-speaking population (n = 571, age 38.24 ± 7.65 years, female = 46.2%) was recruited from industries and office workers with three occupational task inclusion criteria: assembly, office, and lifting. Psychometric properties included validity for face (from confirmed clarity, simplicity, and readability), content (via the content validity index); and construct (through known group validity); additionally, the properties of internal consistency (Cronbach's α); and test-retest reliability (Kappa coefficient of agreement) were considered.

RESULTS

No significant issues during the translation process were found. The NMQ-E-P showed adequate internal consistency for all regions (α ≥ 0.87). The test-retest reliability was examined with Kappa agreement correlation coefficient and all items, except ankle regions, showed very good agreements (Kappa coefficient = 0.87-1.0). Excellent ICC values were obtained for quantitative variables (ICC > 0.88) and good construct validity was revealed (p < 0.001).

CONCLUSION

The Persian version of the NMQ-E has very good validity and reliability and can be used by researchers and professionals to evaluate the prevalence of MSDs in nine body regions simultaneously.

Reliability and Validity of Six Selected Observational Methods for Risk Assessment of Hand Intensive and Repetitive Work

Risk assessments of hand-intensive and repetitive work are commonly done using observational methods, and it is important that the methods are reliable and valid. However, comparisons of the reliability and validity of methods are hampered by differences in studies, e.g., regarding the background and competence of the observers, the complexity of the observed work tasks and the statistical methodology. The purpose of the present study was to evaluate six risk assessment methods, concerning inter- and intra-observer reliability and concurrent validity, using the same methodological design and statistical parameters in the analyses. Twelve experienced ergonomists were recruited to perform risk assessments of ten video-recorded work tasks twice, and consensus assessments for the concurrent validity were carried out by three experts. All methods' total-risk linearly weighted kappa values for inter-observer reliability (when all tasks were set to the same duration) were lower than 0.5 (0.15-0.45). Moreover, the concurrent validity values were in the same range with regards to total-risk linearly weighted kappa (0.31-0.54). Although these levels are often considered as being fair to substantial, they denote agreements lower than 50% when the expected agreement by chance has been compensated for. Hence, the risk of misclassification is substantial. The intra-observer reliability was only somewhat higher (0.16-0.58). Regarding the methods ART (Assessment of repetitive tasks of the upper limbs) and HARM (Hand Arm Risk Assessment Method), it is worth noting that the work task duration has a high impact in the risk level calculation, which needs to be taken into account in studies of reliability. This study indicates that when experienced ergonomists use systematic methods, the reliability is low. As seen in other studies, especially assessments of hand/wrist postures were difficult to rate. In light of these results, complementing observational risk assessments with technical methods should be considered, especially when evaluating the effects of ergonomic interventions.

Application of QBA to Assess the Emotional State of Horses during the Loading Phase of Transport

To identify feasible indicators to evaluate animals' emotional states as a parameter to assess animal welfare, the present study aimed at investigating the accuracy of free choice profiling (FCP) and fixed list (FL) approach of Qualitative Behaviour Assessment (QBA) in horses during the loading phase of transport. A total of 13 stakeholders were trained to score 2 different sets of videos of mixed breed horses loaded for road transport, using both FCP and FL, in 2 sessions. Generalized Procustes Analysis (GPA) consensus profile explained a higher percentage of variation (80.8%) than the mean of 1000 randomized profiles (41.2 ± 1.6%; p = 0.001) for the FCP method, showing an excellent inter-observer agreement. GPA identified two main factors, explaining 65.1% and 3.7% of the total variation. Factor 1 ranging from 'anxious/ to 'calm/relaxed', described the valence of the horses' emotional states. Factor 2, ranging from 'bright' to 'assessing/withdrawn', described the arousal. As for FL, Principal Component Analysis (PCA) first and second components (PC1 and PC2, respectively), explaining on average 59.8% and 12.6% of the data variability, had significant agreement between observers. PC1 ranges from relaxed/confident to anxious/frightened, while PC2 from alert/inquisitive to calm. Our study highlighted the need for the use of descriptors specifically selected, throughout a prior FCP process for the situation we want to evaluate to get a good QBA accuracy level.

The problem with "ergonomics injuries": What can ergonomists do?

Effects of psychosocial hazards on risk of musculoskeletal disorders (MSDs) are often very substantial, but workplace risk management practices focus largely on biomechanical hazards, as do the risk assessment methods used by ergonomists. Translation of research evidence into more effective workplace practices demands a more holistic risk management framework that encompasses both types of hazard. In this context, we evaluate the validity of different MSD risk assessment methods for different purposes, focusing particularly on requirements for routine workplace risk management. These include choice of fit-for-purpose assessment methods, prioritisation of hazards that are most affecting risk, and control actions as high as possible in the risk control hierarchy. Ergonomists could facilitate more effective workplace risk management by promoting: awareness of the need for change; improvements to guidance from OHS regulators; research on MSD-related workplace management issues; and professional development programs on this topic for ergonomists and other OHS practitioners.

The non-explicit observational method is reproducible and valid in the analysis of occupational biomechanical exposure of workers

BACKGROUND: An analysis of workers’ exposure to biomechanical risk factors in the workplace with a high methodological quality allows for stronger evidence of the relationship between risk factors and musculoskeletal disorders. OBJECTIVE: To evaluate the measurement properties of non-explicit observational methods. METHODS: Psychometric study design that included 50 workers in an analysis of occupational tasks (n = 50 video tasks) using a non-explicit observational method, the Rapid Entire Body Assessment (REBA) method, and a workers’ self-report on their perception of their biomechanical occupational exposure. The reliability was tested by a non-explicit method and the REBA method. The validity of the non-explicit method was tested using the REBA method and the workers’ self-report, according to COSMIN guidelines. RESULTS: The intra- and inter-evaluator reliability of the non-explicit observational method ranged from moderate to strong (ICC2.1  = 0.45 to 0.87), and the agreement was acceptable (SEM = 0.60 to 2.79), expect for neck region. The REBA method showed intra-evaluator reliability to be moderate to excellent (ICC2.1  = 0.50 to 1.00), inter-evaluator reliability to be poor to strong (ICC2.1  = –0.17 to 0.83), and intra- and inter-evaluator agreement to be poor to moderate (SEM = 0.00 to 0.74). The concurrent validity between the non-explicit and REBA methods showed a strong positive correlation. CONCLUSION: The non-explicit observational method of biomechanical exposure analysis presented reproducible and valid measurement properties. Methods that present better measurement properties provide professionals with a better basis for analysis and assist in decision-making to reduce or eliminate risk exposure.

Workplace physical and psychosocial hazards: A systematic review of evidence informed hazard identification tools

Prevention of musculoskeletal disorders (MSDs) requires the identification of physical and psychosocial hazards. This systematic review aimed to identify accessible and validated tools, for the assessment of workplace physical and psychosocial hazards, and consolidate the results into a matrix for use by work health and safety (WHS) professionals. Web of Science, Medline, ProQuest Central, and PsychInfo electronic databases, along with grey literature, were searched (Jan 1990 to July 2020). Studies that included tools with evidence of validity for the identification of physical hazards, psychosocial hazards, or both were included. A total of 83 tools were identified and then reviewed to ensure the tools were accessible. The final matrix included a total of 26 tools (16 physical, 4 psychosocial, and 6 comprehensive [physical and psychosocial]). Evidence on best practice for MSD mitigation supports the need for a comprehensive approach; however, the current review identified limitations in the availability of such tools to support WHS professionals.

The Role of Diffusion Weighted MR Imaging in the Diagnosis of Tendon Injuries of the Ankle and Foot

Background and objectives: Our aim is to determine the diagnostic performance and utility of Diffusion Weighted MR Imaging (DWI) against the routine Magnetic Resonance Imaging (MRI) for the evaluation of patients with tendon injuries of the ankle and foot. Materials and Method: After institutional review board approval and informed consent taken from all the patients, ankle and foot MR imaging and DWI-Apparent Diffusion Coefficient (ADC) mapping were performed on the 81 injured tendons of 50 patients. All tendon injuries were named as Rupture (R), Partial tear (PT), and Tenosynovitis (T). Diagnostic interpretation was based on the MRI-DWI and ADC mapping, verified by either open surgery, diagnostic arthroscopy, or conservative procedures-splint application. Statistical analysis of this research was assessed by Fischer’s exact test, variance analysis test between dependent groups, Receiver Operating Characteristics (ROC) curve, and Pearson chi square statistics. Results: MRI depicted all tendon injuries with 70% sensitivity and 100% specificity, and showed a significant statistical relationship to surgical and arthroscopic references with high agreement (p < 0.05, k: 0.609). DWI had 100% sensitivity and 83–90% specificity for the visualization of tendon injuries with certain agreement and a significant statistical relationship to the gold standard (p < 0.05, k: 0.890–0.899). For all those injured tendons, DWI had 100% sensitivity for the diagnosis of R, and 92–97% sensitivity corresponding to PT and T over routine ankle MR imaging. The specificity of DWI to MRI ranged from 75 to 44% for all the injured tendons. DWI had significant statistical superiority over MRI for the visualization of R, PT, and T of all tendons included in this research (p < 0.05). Conclusions: DWI is a good imaging modality for the visualization of ankles with tendon injuries, possibly further improving the sensitivity of the classical ankle and foot MRI, and supplying more beneficial and diagnostic information than routine MR imaging on the basis of R, PT, and T of tendons at the ankle and foot.

Action Levels for the Prevention of Work-Related Musculoskeletal Disorders in the Neck and Upper Extremities: A Proposal

There are several well-known risk factors for work-related musculoskeletal disorders (MSDs). Despite this knowledge, too many people still work in harmful conditions. The absence of occupational exposure limits (OELs) for physical workload impedes both supervision and preventive work. To prevent myalgia, tendon disorders, and nerve entrapments in the upper musculoskeletal system, we propose action levels concerning work postures, movement velocities and muscular loads recorded by wearable equipment. As an example, we propose that wrist velocity should not exceed 20°/s as a median over a working day. This has the potential to reduce the prevalence of carpal tunnel syndrome (CTS) in highly exposed male occupational groups by 93%. By reducing upper arm velocity in highly exposed female groups to the suggested action level 60°/s, the prevalence of pronounced neck/shoulder myalgia with clinical findings (tension neck syndrome) could be reduced by 22%. Furthermore, we propose several other action levels for the physical workload. Our ambition is to start a discussion concerning limits for physical workload, with the long-term goal that OELs shall be introduced in legislation. Obviously, the specific values of the proposed action levels can, and should, be discussed. We hope that quantitative measurements, combined with action levels, will become an integral part of systematic occupational health efforts, enabling reduction and prevention of work-related MSDs.

Measurements and observations of movements at work for warehouse forklift truck operators

Inclinometry and video analyses can provide objective measures of physical workloads. The study aim was to measure and observe arm, back and head postures and movements among forklift truck operators (FLTOs) during a working day, analyzing differences between types of forklift trucks and to assess reported workload and health. Twenty-five male FLTOs in a high-level warehouse were randomly included. The data collected comprised technical measurements, video analyses of postures and movements, and a questionnaire measuring health, pain and workload. On average, the FLTOs rotated their head more than 45°, in total, 232 times/h. Video analysis revealed that FLTOs periodically drive the forklift truck sideways with the head rotated in the direction of travel, and in periods look upwards, in which the head is highly rotated and extended. Inclinometry and observations during the working day has the potential to be a valuable part of risk assessment promoting occupational safety and health.

Intraoperative musculoskeletal discomfort and risk for surgeons during open and laparoscopic surgery

BACKGROUND

Surgeon workload is significant both mentally and physically and may differ by procedure type. When comparing laparoscopic surgery and open surgery, studies have reported contrasting results on the physical and mental workload assessed.

METHODS

Wearable posture sensors and pre-/post-surgical questionnaires were employed to assess intraoperative workload and to identify risk factors for surgeons using objective and subjective measures.

RESULTS

Data from 49 cases (27 open and 22 laparoscopic surgeries performed by 13 male and 11 female surgeons) were assessed. More than half the surgeons reported a clinically relevant post-surgical fatigue score. The surgeons also self-reported a significant increase in pain for the neck, upper back, and lower back during/after surgery. Procedural time had significant impacts on fatigue, body part pain, and subjective (NASA-TLX) workload. The objectively assessed intraoperative work postures using wearable sensors showed a high musculoskeletal risk for neck and lower back based on their posture overall. Open surgeries had significantly larger neck angles (median [IQR]: 40 [28-47]°) compared with laparoscopic surgeries (median [IQR]: 23 [16-29]°), p < 0.001) and torso (median [IQR]: 17 [14-22]° vs. 13 [10-17]°, p = 0.006).

CONCLUSION

Surgeons reported significantly higher levels of fatigue and pain in the neck and lower back during or after performing a surgical case. Longer procedural time resulted in more self-rated fatigue, pain, and subjective workload. Open surgery had higher postural risk. Overall, surgeons spent a disturbingly high percentage of time during surgery in high-risk musculoskeletal postures, especially the neck. These results show that intraoperative postural risk is very high and that interventions are necessary to protect surgeon musculoskeletal health for optimal surgeon performance and career longevity.

The RAMP package for MSD risk management in manual handling - A freely accessible tool, with website and training courses

In this paper the RAMP Package is presented with the objective to facilitate the application of the RAMP tool to systematically manage MSD risks. The package consists of the RAMP tool (Risk Assessment and Management tool for manual handling Proactively), the RAMP website, and free, globally available online, training courses (MOOCs). An Action module used for managing identified MSD risks is introduced. The tool, encompassing a wide range of risks, is applicable to the whole risk management process. Furthermore, RAMP is openly available for download, and free to use. The RAMP tool and training materials were developed using a participative iterative methodology including researchers and practitioners. RAMP was downloaded in 86 countries in the first 26 months since its' launch and over 2400 learners from high-, middle- and low-income countries have joined the MOOCs. The RAMP Package meets organisations' needs for an accessible, comprehensive risk assessment and management tool.

Development and evaluation of RAMP II - a practitioner's tool for assessing musculoskeletal disorder risk factors in industrial manual handling

RAMP II is an observation-based tool developed for assessing a wide range of musculoskeletal disorder risk factors related to industrial manual handling. RAMP II, which is part of the RAMP tool, is based on research studies and expert judgments. The assessment relies mainly on direct or video observations of the work being assessed, but additionally on measured push/pull forces and weights of handled objects, and on perceived workload and discomfort. Over 80 practitioners participated in the development of the tool. According to the evaluations, 73% of the assessment items evaluated had acceptable reliability, and the majority of the potential end-users reported that RAMP II is usable for assessing risks and as a decision base. It is concluded that this study provides support that RAMP II is usable for risk assessment of musculoskeletal disorder risk factors in industrial manual handling. Practitioner summary: RAMP II is an observation-based assessment tool for screening and assessing major musculoskeletal exposures in industrial manual handling jobs. Over 80 practitioners participated in the development of the tool. This study provides support that RAMP II is usable for risk assessment of musculoskeletal disorder risk factors in industrial manual handling. Abbreviations: CTS: carpal tunnel syndrome; HARM: the Hand Arm Risk Assessment method; IMP: intramuscular pressure; κ_w: linearly weighted kappa; LBD: lower back disorders; LBP: lower back pain; MAWL: maximum acceptable weight of lift; MHO: manual handling operations; MSD: musculoskeletal disorder; MNSD: neck-shoulder disorder; NSP: neck-shoulder pain; OCRA: the Occupational Repetitive Action methods; OHS: occupational health and safety; PABAK: prevalence and bias adjusted kappa; p₀: proportion of agreement; RAMP: Risk Assessment and Management tool for manual handling Proactively; ROM: range of motion; RPL: risk and priority level; RSI: the Revised Strain Index; RULA: the Rapid Upper Limb Assessment; SWEA: Swedish Work Environment Authority; UEMSDs: upper-extremity work-related musculoskeletal disorders; WMSD: work-related musculoskeletal disorder; WRMSD: work-related musculoskeletal disorder; workday_8h: eight hours workday.

Inter- and intra-rater reliability of the OCRA checklist method in video-recorded manual work tasks

Observation-based risk assessments are often used for evaluation of biomechanical workload and the condition of the workplace ergonomics. However, the inter- and intra-rater reliability of the methods used for the assessments are insufficiently studied. The OCRA checklist method, included as a reference method in the ISO and CEN standards regarding upper limb repetitive risk assessment, was in this study investigated regarding its reliability. Eleven ergonomists were educated within the method. Each ergonomist risk-assessed ten video-recorded manual work tasks, on two occasions. The average inter-rater agreement of the five overall risk levels was 39% and the linearly weighted kappa was 0.43, the intra-rater dittos were 45% and 0.52. Both indicating a moderate reliability, but lower than what could be expected. The levels might be sufficient for coarse surveys. However, for risk assessments before and after an intervention, complementing technical methods should be considered.

On the OCRA Measurement: Automatic Computation of the Dynamic Technical Action Frequency Factor

OCRA (OCcupational Repetitive Action) is currently one of the most widespread procedures for assessing biomechanical risks related to upper limb repetitive movements. Frequency factor of the technical actions represents one of the OCRA elements. Actually, the frequency factor computation is based on workcycle video analysis, which is time-consuming and may lead to up to 30% of intra-operator variability. This paper aims at proposing an innovative procedure for the automatic counting of dynamic technical actions on the basis of inertial data. More specifically, a threshold-based algorithm was tested in four industrial case studies, involving a cohort of 20 workers. Nine combinations of the algorithm were tested by varying threshold values related to time and amplitude. The computation of frequency factor showed an average relative error lower than 5.7% in all industrial-based case studies after the appropriate selection of the time and amplitude threshold values. These findings open the possibility to use the threshold-based algorithm proposed here for the automatic computation of OCRA frequency factor, avoiding the time efforts in video analysis.

Impact of Procedure Type, Case Duration, and Adjunctive Equipment on Surgeon Intraoperative Musculoskeletal Discomfort

BACKGROUND

Surgeons are at high risk of developing musculoskeletal disorders.

STUDY DESIGN

This study was designed to identify risk factors and assess intraoperative physical stressors using subjective and objective measures, including type of procedure and equipment used. Wearable sensors and pre- and postoperation surveys were analyzed.

RESULTS

Data from 116 cases (34 male and 19 female surgeons) were collected across surgical specialties. Surgeons reported increased pain in the neck, upper, and lower back both during and after operations. High-stress intraoperative postures were also revealed by the real-time measurement in the neck and back. Surgical duration also impacted physical pain and fatigue. Open procedures had more stressful physical postures than laparoscopic procedures. Loupe usage negatively impacted neck postures.

CONCLUSIONS

This study highlights the fact that musculoskeletal disorders are common in surgeons and characterizes surgeons' intraoperative posture as well as surgeon pain and fatigue across specialties. Defining intraoperative ergonomic risk factors is of paramount importance to protect the well-being of the surgical workforce.

Factors influencing ergonomists' use of observation-based risk-assessment tools

BACKGROUND:

Several observation-based risk-assessment tools have been developed in recent decades. Studies reporting their use often focus only on the user, the ergonomist. The influence of context and the attributes of the tools may also affect the use but are factors that are seldom considered.

OBJECTIVE:

The aim of the present study was to explore the process of risk-assessment assignments and to identify factors influencing the use of research-based observation-based risk-assessment tools among Swedish ergonomists, with a background as reg. physiotherapists, employed in Occupational Health Services (OHS).

METHODS:

A web-based questionnaire (n = 70) was combined with semi-structured interviews (n = 12).

RESULTS:

There was limited use of several observation-based risk-assessment tools. Furthermore, the results showed that ergonomics risk-assessment assignments are most commonly initiated reactively and that interventions were seldom evaluated. Factors that influence use are related both to the ergonomist and to the attributes of the tools as well as to contextual factors assigned to authorities, and internal organisations both within occupational health service companies and client companies.

CONCLUSION:

There was a lack of systematic approaches in ergonomics risks assessment and low use and knowledge of risk-assessment tools. This indicates that there is a need to support OHS companies in implementing systematic tools in their practice.

A machine-learning method for classifying and analyzing foot placement: Application to manual material handling

Foot placement strategy is an essential aspect in the study of movement involving full body displacement. To get beyond a qualitative analysis, this paper provides a foot placement classification and analysis method that can be used in sports, rehabilitation or ergonomics. The method is based on machine learning using a weighted k-nearest neighbors algorithm. The learning phase is performed by an observer who classifies a set of trials. The algorithm then automatically reproduces this classification on subsequent sets. The method also provides detailed analysis of foot placement strategy, such as estimating the average foot placements for each class or visualizing the variability of strategies. An example of applying the method to a manual material handling task demonstrates its usefulness. During the lifting phase, the foot placements were classified into four groups: front, contralateral foot behind, ipsilateral foot behind, and parallel. The accuracy of the classification, assessed with a holdout method, is about 97%. In this example, the classification method makes it possible to observe and analyze the handler's foot placement strategies with regards to the performed task.

The Quick Exposure Check (QEC) - Inter-rater reliability in total score and individual items

The development of musculoskeletal disorders has been linked to various risk factors in the work environment including lifting heavy loads, machine and materials handling, work postures, repetitive work, work with handheld vibrating tools, and work stress. The Quick Exposure Check (QEC) was designed to assess exposure to work-related musculoskeletal risk factors affecting the back, shoulder/arm, wrist/hand, and neck. We investigated the inter-rater reliability of the summary scores and individual items of the QEC by comparing two simultaneous assessments of 51 work tasks, performed by 14 different workers. The work tasks were mainly "light" to "moderately heavy". For total scores, the level of disagreement for shoulder/arm had a Relative Position of 0.13 (95% CI: 0.02; 0.23) and no statistically significant random disagreement. Percentage agreement was 63-100% for individual items and 71-88% for total score. Weighted Kappa of agreement for the individual items rated by the assessors were -0.94-0.77; highest for back motion, and lowest for wrist/hand position. The Swedish translation of the Quick Exposure Check has moderate to very good inter-rater reliability with fair to slight levels of systematic disagreement. There was no statistically significant random disagreement.

Work-related neck and upper limb disorders - quantitative exposure-response relationships adjusted for personal characteristics and psychosocial conditions

BACKGROUND

We have previously reported quantitative exposure-response relationships between physical exposures recorded by technical methods, and complaints and diagnoses in the neck/shoulders, and the elbows/hands, based on group data. In the present study the number of workers was doubled, and information on individual factors, and psychosocial working conditions was used. Relationships between various kinds of exposure and response have been analysed in this larger and more detailed sample.

METHODS

The prevalence of complaints (Nordic Questionnaire) and diagnoses (clinical examination) were recorded in a number of occupational groups within which the participants had similar work tasks, 34 groups of female employees (N = 4733 women) and 17 groups of male employees (N = 1107 men). Age and other individual characteristics were recorded, as well as psychosocial work environment factors (job-content questionnaire) for most participants. Postures and velocities (inclinometry) of the head (N = 505) and right upper arm (N = 510), right wrist postures and velocities (electrogoniometry; N = 685), and muscular activity (electromyography; EMG) in the right trapezius muscle (N = 647) and forearm extensors (N = 396) were recorded in representative sub-groups. Exposure-response relationships between physical exposure and musculoskeletal disorders, adjusted for individual factors with Poisson regression were then calculated. The effect of introducing psychosocial conditions into the models was also assessed.

RESULTS

Associations were found between head velocity, trapezius activity, upper arm velocity, forearm extensor activity and wrist posture and velocity, and most neck/shoulder and elbow/hand complaints and diagnoses. Adjustment for age, other individual characteristics and psychosocial work conditions had only a limited effect on these associations. For example, the attributable fraction for tension neck syndrome among female workers with the highest quintile of trapezius activity was 58%, for carpal tunnel syndrome versus wrist velocity it was 92% in men in the highest exposure quintile.

CONCLUSIONS

Based on the findings, we propose threshold limit values for upper arm and wrist velocity.

P-Ergonomics Platform: Toward Precise, Pervasive, and Personalized Ergonomics using Wearable Sensors and Edge Computing

Preventive healthcare has attracted much attention recently. Improving people’s lifestyles and promoting a healthy diet and wellbeing are important, but the importance of work-related diseases should not be undermined. Musculoskeletal disorders (MSDs) are among the most common work-related health problems. Ergonomists already assess MSD risk factors and suggest changes in workplaces. However, existing methods are mainly based on visual observations, which have a relatively low reliability and cover only part of the workday. These suggestions concern the overall workplace and the organization of work, but rarely includes individuals’ work techniques. In this work, we propose a precise and pervasive ergonomic platform for continuous risk assessment. The system collects data from wearable sensors, which are synchronized and processed by a mobile computing layer, from which exposure statistics and risk assessments may be drawn, and finally, are stored at the server layer for further analyses at both individual and group levels. The platform also enables continuous feedback to the worker to support behavioral changes. The deployed cloud platform in Amazon Web Services instances showed sufficient system flexibility to affordably fulfill requirements of small to medium enterprises, while it is expandable for larger corporations. The system usability scale of 76.6 indicates an acceptable grade of usability.

Effects of a Participatory Ergonomics Intervention With Wearable Technical Measurements of Physical Workload in the Construction Industry: Cluster Randomized Controlled Trial

Background

Construction work frequently involves heavy physical work, and a reduction of the physical workload should have high priority. Technological development has made it possible to obtain field measurements with surface electromyography (sEMG), kinematics measured with inertial measurement units (IMUs), and video recordings. However, no studies have used these methods simultaneously to detect situations with excessive physical workload (events) during a working day. Thus, knowledge about these specific events may combat work-related risk factors. Participatory ergonomics (PE) has shown promising results, but whether it can be used as a tool to reduce the physical workload during construction work remains unknown.

Objective

This cluster randomized controlled trial investigated whether a PE intervention with technical measurements consisting of IMUs, sEMG, heart rate monitoring, and video recordings of physical workload could reduce the number of events with excessive physical workload during a working day. Furthermore, other outcomes were obtained from questionnaires.

Methods

A total of 80 male full-time construction workers (aged 19 to 67 years) were randomized at the cluster level (gang) to a PE intervention consisting of 3 workshops (7 gangs and 32 workers) or to a control group (8 gangs and 48 workers). The physical workload was recorded by technical measurements, that is, IMUs, sEMG, heart rate monitoring, and video recordings during a full working day at baseline and 3 and 6 months’ follow-up. On the basis of the technical measurements, a custom-made computer program detected the situations (events) where the construction workers were exposed to excessive physical workload and used in the intervention. Differences in the number of events from baseline to follow-up between intervention and control were evaluated using linear mixed models (intention-to-treat), with individual nested in cluster as a random factor. Furthermore, questionnaires were filled out on test days.

Results

The results of the primary outcome showed no change in the number of events with excessive physical workload. However, compared with the control group, the other outcomes showed decreased general fatigue after a typical working day (P=.001) and increased influence on own work (P=.04).

Conclusions

This PE intervention with technical measurements did not reduce the number of events with excessive physical workload during construction work. However, the intervention led to decreased general fatigue and increased influence on own work.

Trial Registration

ClinicalTrials.gov NCT02498197; https://clinicaltrials.gov/ct2/show/NCT02498197 (Archived by WebCite at http://www.webcitation.org/74SZ3DIWS)

Self-recordings of upper arm elevation during cleaning - comparison between analyses using a simplified reference posture and a standard reference posture

BACKGROUND

To reduce ergonomic risk factors in terms of awkward and constrained postures and high velocities, it is important to perform adequate risk assessments. Technical methods provide objective measures of physical workload. These methods have so far mainly been used by researchers. However, if written instructions how to apply the sensors and how to adopt the reference posture are provided, together with triaxial accelerometers, it may be possible for employees to record their own physical workload. The exposure in terms of e.g. upper arm elevations could then easily be assessed for all workers in a workplace. The main aims of this study were: 1) to compare analyses for self-recording of upper arm elevation during work using a simplified reference posture versus using a standard reference posture, and 2) to compare the two reference postures.

METHODS

Twenty-eight cleaners attached an accelerometer to their dominant upper arm and adopted a simplified reference according to a written instruction. They were thereafter instructed by a researcher to adopt a standard reference. Upper arm elevations were recorded for 2 or 3 days. Each recording was analysed twice; relative to the simplified reference posture and relative to the standard reference posture. The group means of the differences in recorded upper arm elevations between simplified and standard reference analyses were assessed using Wilcoxon signed ranks test. Furthermore, we calculated the group mean of the differences between the simplified reference posture and the standard reference posture.

RESULTS

For arm elevation during work (50th percentile), the group mean of the differences between the two analyses was 0.2° (range -7 - 10°). The group mean of the differences between the two references was 9° (range 1 - 21°). The subjects were able to follow the instructions in the protocol and performed self-recording of upper arm elevation and velocity.

CONCLUSIONS

The small difference between the two analyses indicates that recordings performed by employees themselves are comparable, on a group level, with those performed by researchers. Self-recordings in combination with action levels would provide employers with a method for risk assessment as a solid basis for prevention of work-related musculoskeletal disorders.

Wearable Monitoring Devices for Biomechanical Risk Assessment at Work: Current Status and Future Challenges-A Systematic Review

Background: In order to reduce the risk of work-related musculoskeletal disorders (WMSDs) several methods have been developed, accepted by the international literature and used in the workplace. The purpose of this systematic review was to describe recent implementations of wearable sensors for quantitative instrumental-based biomechanical risk assessments in prevention of WMSDs. Methods: Articles written until 7 May 2018 were selected from PubMed, Scopus, Google Scholar and Web of Science using specific keywords. Results: Instrumental approaches based on inertial measurement units and sEMG sensors have been used for direct evaluations to classify lifting tasks into low and high risk categories. Wearable sensors have also been used for direct instrumental evaluations in handling of low loads at high frequency activities by using the local myoelectric manifestation of muscle fatigue estimation. In the field of the rating of standard methods, on-body wireless sensors network-based approaches for real-time ergonomic assessment in industrial manufacturing have been proposed. Conclusions: Few studies foresee the use of wearable technologies for biomechanical risk assessment although the requirement to obtain increasingly quantitative evaluations, the recent miniaturization process and the need to follow a constantly evolving manual handling scenario is prompting their use.

Accuracy of identification of low or high risk lifting during standardised lifting situations

The aim was to classify lifting activities into low and high risk categories (according to The Danish Working Environment Authority guidelines) based on surface electromyography (sEMG) and trunk inclination (tri-axial accelerometer) measurements. Lifting tasks with different weights, horizontal distance and technique were performed. The lifting tasks were characterised by a feature vector composed of either the 90th, 95th or 99th percentile of sEMG activity level and trunk inclinations during the task. Linear Discriminant Analysis and a subject-specific threshold scheme were applied and lifting tasks were classified with an accuracy of 65.1-65.5%. When lifts were classified based on the subject-specific threshold scheme from low and upper back accelerometers, the accuracy reached 52.1-58.1% and 72.7-78.1%, respectively. In conclusion, the use of subject-specific thresholds from sEMG from upper trapezius and erector spinae as well as inclination of the upper trunk enabled us to identify low and high risk lifts with an acceptable accuracy. Practitioner Summary: This study contributes to the development of a method enabling the automatic detection of high risk lifting tasks, i.e. exposure to high biomechanical loads, based on individual sEMG and kinematics from an entire working day. These methods may be more cost-effective and may complement observations commonly used by practitioners.

On-site detection of equid alphaherpesvirus 3 in perineal and genital swabs of mares and stallions

Equine coital exanthema (ECE) is an infectious, venereally transmitted muco-cutaneous disease affecting mares and stallions, caused by equid alphaherpesvirus 3 (EHV3). Diagnostic tools for rapid identification of EHV3 are of primary importance to diminish the risk of EHV3 dissemination at the time of breeding. In the last years, it has been shown that the performance of the insulated-isothermal polymerase chain reaction (iiPCR) is comparable to virus isolation, nested PCR and real-time PCR (qPCR) in detecting pathogens of various animal species. Analytical sensitivity and specificity of the iiPCR were compared with a qPCR, using a plasmid containing the target region of the EHV3 glycoprotein G gene and an Argentinian EHV3 isolate (E/9283/07 C3A). In order to evaluate the diagnostic performance of the iiPCR, nucleic acids of 85 perineal and genital swabs (PGS) of mares and stallions were extracted by taco^TM mini and tested by both techniques. EHV3 was detected in 46 and 45 of the 85 PGS by the iiPCR and qPCR, respectively. There was almost perfect agreement between the two diagnostic methods (98.82%; 95% CI: 95.03-100%; κ = 0.98). The iiPCR had a limit of detection of 95.00% at 6 genome equivalents per reaction and a detection endpoint for viral DNA comparable to that of the qPCR, and did not react with six non-targeted equine pathogens. The iiPCR represents a sensitive and specific method for the rapid on-site diagnosis of EHV3 infection. Its routinely implementation in breeding facilities, and artificial insemination and embryo transfer centers, will contribute to prevent the dissemination of this venereal, highly contagious disease in horses.