Current techniques for assessing physical exposure to work-related musculoskeletal risks, with emphasis on posture-based methods

Auto-AzKNIOSH: an automatic NIOSH evaluation with Azure Kinect coupled with task recognition

Standard Ergonomic Risk Assessment (ERA) from video analysis is a highly time-consuming activity and is affected by the subjectivity of ergonomists. Motion Capture (MOCAP) addresses these limitations by allowing objective ERA. Here a depth camera, one of the most commonly used MOCAP systems for ERA (i.e. Azure Kinect), is used for the evaluation of the NIOSH Lifting Equation exploiting a tool named AzKNIOSH. First, to validate the tool, we compared its performance with those provided by a commercial software, Siemens Jack TAT, based on an Inertial Measurement Units (IMUs) suit and found a high agreement between them. Secondly, a Convolutional Neural Network (CNN) was employed for task recognition, automatically identifying the lifting actions. This procedure was evaluated by comparing the results obtained from manual detection with those obtained through automatic detection. Thus, through automated task detection and the implementation of Auto-AzKNIOSH we achieved a fully automated ERA.Practitioner Summary:The standard evaluation of the NIOSH Lifting Equation is time-consuming and subjective, thus a new automatic tool is designed, which integrates motion captures provided by Azure Kinect and task recognition. We found a high agreement between our tool and Siemens Jack TAT suit, the golden standard technology for motion capture.

Comparing risk assessment methods for work-related musculoskeletal disorders with in vivo joint loads during manual materials handling

The validity of observational methods in ergonomics is still challenging research. Criterion validity in terms of concurrent validity is the most commonly studied. However, studies comparing observational methods with biomechanical values are rare. Thus, the aim of this study is to compare the Ovako Working Posture Analysing System (OWAS) and the Rapid Entire Body Assessment (REBA) with in vivo load measurements at hip, spine, and knee during stoop and squat lifting of 14 participants. The results reveal that OWAS and REBA action levels (AL) can distinguish between different in vivo load measurements during manual lifting. However, the results also reveal that the same OWAS- and REBA-AL do not necessarily provide equal mean values of in vivo load measurements. For example, resultant contact force in the vertebral body replacement for squat lifting ranged from 57% body weight (%BW) in OWAS-AL1 to 138%BW in OWAS-AL3 compared to 46%BW in REBA-AL0 and 173%BW in REBA-AL3. Furthermore, the results suggest that the performed squat lifting techniques had a higher risk for work-related musculoskeletal disorders than the performed stoop lifting techniques.

Physical Ergonomic Assessment in Cleaning Hospital Operating Rooms Based on Inertial Measurement Units

Workers involved in hospital operating room cleaning face numerous constraints that may lead to musculoskeletal disorders. This study aimed to perform physical ergonomic assessments on hospital staff by combining a continuous assessment (RULA) based on inertial measurement units with video coding. Eight participants performed cleaning tasks while wearing IMUs and being video recorded. A subjective evaluation was performed through the Nordic questionnaire. Global RULA scores equaled 4.21 ± 1.15 and 4.19 ± 1.20 for the right and left sides, respectively, spending most of the time in the RULA range of 3-4 (right: 63.54 ± 31.59%; left: 64.33 ± 32.33%). Elbows and lower arms were the most exposed upper body areas with the highest percentages of time spent over a risky threshold (right: 86.69 ± 27.27%; left: 91.70 ± 29.07%). The subtask analysis identified 'operating table moving', 'stretcher moving', and 'trolley moving' as the riskiest subtasks. Thus, this method allowed an extensive ergonomic analysis, highlighting both risky anatomical areas and subtasks that need to be reconsidered.

Identification of movement phenotypes from occupational gesture kinematics: Advancing individual ergonomic exposure classification and personalized training

The identification of personalized preventive strategies plays a major role in contrasting the occurrence of work-related musculoskeletal disorders. This requires the identification of distinct movement patterns within large samples and the attribution of a proper risk level to each identified movement phenotype. We assessed the feasibility of this approach by exploiting wearable inertial measurement units to estimate the whole-body kinematics of 43 healthy participants performing 18 reach-to-manipulate movements, which differed based on the object's position in the space and the type of manipulation required. Through unsupervised clustering, we identified multiple movement phenotypes graded by ergonomic performance. Furthermore, we determined which joints mostly contributed to instantiating the ergonomic differences across clusters, emphasizing the importance of monitoring this aspect during occupational gestures. Overall, our analysis suggests that movement phenotypes can be identified within occupational motor repertoires. Assigning individual performance to specific phenotypes has the potential to inform the development of more effective and tailored interventions.

Task-based evaluation of WRMSDs prevailing amongst workers in building construction: An occupational and socioeconomic perspective

BACKGROUND

The construction of buildings is risky for workers' musculoskeleton.

OBJECTIVE

This study aims to calculate the significance of risk associated with work-related musculoskeletal disorders.

METHOD

600 workers from 20 construction sites were surveyed using the Nordic Musculoskeletal Questionnaire (modified) and their performance was assessed at seven construction-tasks using RULA and REBA sheets. SPSS v. 26 and R programming were used for statistical analysis.

RESULTS

The mean value of workers' age was 28.4381 years, with 8.8205 working months/year and 65USDs monthly earnings. Maximum reporting of body discomfort was by workers of window/door framing. Workers' BMI (35-44 kg/m2) and break duration (< 15 minutes) prompted neck pain with OR 7.79 (95% CI 1.135-53.587) and OR 1.179 (95%CI 0.231-6.014) respectively. Bagging was dangerous for the ankle with OR 9.881 (95% CI 5.140-18.994), and window/door framing for feet with OR 2.057 (95% CI 1.196-3.539). The mean value of the RULA grand score ranged from 5.89 (lowest for 'leveling') to 9.25 (highest for 'demolishing'), and the REBA sheet between 8-11 for all seven studied work-stages.

CONCLUSION

Workers' upper and lower limbs are affected by the work-stages they perform and the social lifestyle they live in. These findings from 600 workers are sufficient to be generalized for intervention.

Mismatch between fixed classroom furniture and anthropometric measurements among university students: Relationships to ergonomic risk

BACKGROUND

Appropriate arrangement of classroom ergonomics is necessary for maintaining health and improving academic performance, learning, and motivation.

OBJECTIVE

We aimed to determine the anthropometric measurements and ergonomic risk levels of students during a handwriting activity on a fixed desk and chair and to analyze the mismatch and relationships between these factors.

METHODS

This study included 149 university students (female:73, male:76). Anthropometric measurements (lower and upper extremity length, shoulder height, elbow-rest height, hip-popliteal length, popliteal height, knee height, the distance between tragus and wall, and between acromion and wall) were done with a tape measure. The Rapid Upper Limb Assessment (RULA) tool was conducted to determine the ergonomic risk level while students wrote a standard text on a fixed desk and chair as if they were taking notes in the classroom. The mismatch was evaluated between backrest height and sitting shoulder height, seat height, and popliteal height. The Pearson Chi-Square and the Spearman Correlation test were used for statistical analysis.

RESULTS

The median values of the participants' age, height, weight, and BMI were 22 years, 1.70 m, 68 kg, and 23.18 kg/cm2, respectively. Most students had inadequate ergonomic posture while writing on fixed furniture at the university (Median RULA grand score: 4). More mismatches for seat height (54.4%) were found in high ergonomic risk levels but mismatches for backrest height did not follow a similar result.

CONCLUSIONS

More investigation should be conducted with prospective studies including interventions like adjustable furniture.

Soft computing applications in the field of human factors and ergonomics: A review of the past decade of research

The main objectives of this study were to 1) review the literature on the applications of soft computing concepts to the field of human factors and ergonomics (HFE) between 2013 and 2022 and 2) highlight future developments and trends. Multiple soft computing methods and techniques have been investigated for their ability to address various applications in HFE effectively. These techniques include fuzzy logic, artificial neural networks, genetic algorithms, and their combinations. Applications of these methods in HFE have been highlighted in one hundred and four articles selected from 406 papers. The results of this study help address the challenges of complexity, vagueness, and imprecision in human factors and ergonomics research through the application of soft computing methodologies.

Cross-cultural adaptation and reliability assessment of the Indonesian version of the Computer Workstation Ergonomics: Self-Assessment Checklist

BACKGROUND

Prolonged use of computer devices can have adverse health effects, but these can be mitigated by setting up computer workstations according to ergonomic principles. The Computer Workstation Ergonomics: Self-Assessment Checklist can guide workers in implementing these principles. However, the checklist is only available in English, which may reduce the accuracy of the instrument when used by non-English speakers, including Indonesians.

OBJECTIVE

The objective of this study was to cross-culturally adapt the Computer Workstation Ergonomics: Self-Assessment Checklist for use in Indonesia. Additionally, a reliability assessment was conducted on the adapted checklist.

METHODS

This study followed a six-stage cross-cultural adaptation process, including translation, synthesis of translation, back translation, expert committee review, pretesting, and documentation submission. The final version of the adapted checklist underwent testing for intra-rater reliability, inter-rater reliability, and internal consistency.

RESULTS

The cross-cultural adaptation process resulted in an Indonesian version of the Computer Workstation Ergonomics: Self-Assessment Checklist. Furthermore, the Krippendorff's alpha values for the intra-rater and inter-rater reliability of the adapted checklist ranged from 0.59 to 0.78 (mean = 0.70) and 0.20 to 0.82 (mean = 0.56), respectively.

CONCLUSION

The study produced an Indonesian version of the Computer Workstation Ergonomics: Self-Assessment Checklist that had an adequate reliability. The adapted checklist can serve as a practical tool for evaluating and improving computer workstations in Indonesia.

Selection of ergonomic risk assessment method with pythagorean fuzzy sets: practice in emergency medical services

It is difficult to evaluate ergonomic risk factors in occupations with unpredictable tasks, random demands, and variable settings such as emergency medical services (EMS). This study deals with the problem of selecting an ergonomic risk-evaluation method with Pythagorean Fuzzy Sets (PFSs) based Pythagorean Fuzzy AHP (PF-AHP) and Pythagorean Fuzzy WASPAS (PF-WASPAS) methodology. The method selection criteria were obtained by consulting five different anonymous experts on the candidate criteria obtained from the literature review. The final four main criteria and ten sub-criteria were then decided. After the determination of the decision criteria, five experts were asked to evaluate the criteria and to express their opinions on criteria-alternative scoring by means of a questionnaire for method selection. A two-step method is suggested for the selection of the ergonomic risk-evaluation method. In the first step, PF-AHP is utilized in order to identify the weight of criteria used in the method selection. In the second step, the PF-WASPAS method is proposed in order to OWAS, RULA, and REBA methods. The accuracy and validity of the suggested hybrid model is tested with real data in İstanbul Ambulance Service stations. A sensitivity analysis is carried out to test the reliability of the model. Moreover a comparative analysis is carried out with AHP and Fuzzy AHP methods to identify criteria weights. Study results show that REBA is the most appropriate ergonomic risk-evaluation method in EMS.

Ergonomic human-robot collaboration in industry: A review

In the current industrial context, the importance of assessing and improving workers' health conditions is widely recognised. Both physical and psycho-social factors contribute to jeopardising the underlying comfort and well-being, boosting the occurrence of diseases and injuries, and affecting their quality of life. Human-robot interaction and collaboration frameworks stand out among the possible solutions to prevent and mitigate workplace risk factors. The increasingly advanced control strategies and planning schemes featured by collaborative robots have the potential to foster fruitful and efficient coordination during the execution of hybrid tasks, by meeting their human counterparts' needs and limits. To this end, a thorough and comprehensive evaluation of an individual's ergonomics, i.e. direct effect of workload on the human psycho-physical state, must be taken into account. In this review article, we provide an overview of the existing ergonomics assessment tools as well as the available monitoring technologies to drive and adapt a collaborative robot's behaviour. Preliminary attempts of ergonomic human-robot collaboration frameworks are presented next, discussing state-of-the-art limitations and challenges. Future trends and promising themes are finally highlighted, aiming to promote safety, health, and equality in worldwide workplaces.

Development of an ergonomics risk assessment tool for repetitive task assessment (RTRA)

BACKGROUND

Most ergonomics assessment tools for repetitive task have been used in industries which are mainly focused on assessing the biomechanical risk factors that affect musculoskeletal disorders (MSDs)rather than the psychosocial and work environment risk factors.

OBJECTIVE

To develop a tool for Repetitive Task Risk Assessment (RTRA) and Rapid Upper Limb Assessment (RULA) that can identify biomechanical, physical stress and psychosocial risk factors, prioritize risk reduction action and systematic record keeping.

METHODS

The study consisted of 2 phases; tool development and evaluation of the contents of risk factors by 7 ergonomic experts and intra-rater and inter-rater reliability and validity tests of the tool by 1 researcher and 9 Thai practitioners to assess 30 repetitive tasks.

RESULTS

RULA was modified by adding more biomechanical risk, combining psychosocial and work environment risk factors lead to MSD become the first prototype of RTRA. The Item-Objective Congruence Index (IOC) validated 20 items on usability of each step of the RTRA ranged between 0.64 and 0.93. The examination of the overall intra-rater reliability was 0.932 (95% CI: 0.862-0.967) and the overall inter-rater was 0.956 (95% CI: 0.909-0.978).

CONCLUSION

The tool has high test-retest reliability. There is a suggestion for researchers to understand more on the identification of multiple risk factors in one assessment tool and consider a risk-level rating and scoring for prioritizing risk reduction.

Virtual modelling and analysis of manual material handling activities among warehouse workers in the construction industry

BACKGROUND: Musculoskeletal risks (MSRs) are a major concern among construction warehouse workers due to the lifting, carrying and lowering of heavy loads. OBJECTIVE: The objective of this study was to reduce MSRs among warehouse workers in the construction industry using virtual modelling and analysis of activities. METHODS: A preliminary study was carried out using the Standard Nordic Questionnaire. Biomechanical analysis, Ovako Working posture Assessment System (OWAS) and Rapid Upper Limb Assessment (RULA) were used to analyse the material handling activities. Virtual modelling was used develop the manikins with autoclaved aerated concrete (AAC) blocks at different carriage modes and stacking heights for the analysis. RESULTS: The preliminary study results revealed a higher prevalence of risk at their lower back (73.24%) among the construction warehouse workers. Biomechanical analysis showed a higher risk at L4-L5 joint of lumbar spine during overhead and bending postures for stacking the blocks. Posture analysis results of OWAS indicated a lower risk in overhead carriage mode. Detailed analysis with RULA confirms this result. Mean compressive force values at stacking heights were showed a significant difference (p < 0.05) in 8, 13, 18 and 21 kg AAC blocks. However, stacking height with a range of 120–140 cm was found as safer to the workers by considering all block sizes. CONCLUSION: An ergonomic intervention based on safer stacking heights was developed to reduce MSRs to an acceptable range. It improves productivity of handling the AAC blocks by reducing the cycle time. The intervention can be adapted for handling of similar materials in the construction industry.

Nail job and women’s health: Assessment of ergonomics and occupational hazards

BACKGROUND: The nail job is a new occupation in which the number of people who choose this job is rising. Therefore, the harmful hazards affecting the health of the practitioners should be taken into account. OBJECTIVE: The purpose of this study is to evaluate the ergonomics and occupational health hazards among nail technicians in Iranian society. METHODS: The self-administered questionnaire, the Nordic Musculoskeletal Questionnaire and Novel Ergonomic Postural Assessment (NERPA) method were used to gather data from 80 female nail technicians who participated in this study. RESULTS: More than half of the participants (67.6%) complained of coughing and eye irritation (70%) which was the most frequently reported irritation. The final score of the NERPA was at a high-risk level and the neck pain (63.8%) was the highest in comparison with other parts of the body. There was a significant relationship between activity type with disorder in the neck, elbow, hip, knee, and ankle. Lighting intensity was not significantly associated with musculoskeletal disorders. CONCLUSIONS: Concerning the low work experience, the prevalence of musculoskeletal disorders and, respiratory complaints is high. Hence, the attention of policy-makers to the safety and hygiene issues of women in this occupation is necessary by setting guidelines and considering inspections of occupational health and safety professionals.

Effect of Manual versus Robotic-Assisted Total Knee Arthroplasty on Cervical Spine Static and Dynamic Postures

This study compared surgeon cervical (C) spine postures and repetitive motions when performing traditional manual total knee arthroplasty (MTKA) versus robotic-assisted TKA (RATKA). Surgeons wore motion trackers on T3 vertebra and the occiput anatomical landmarks to obtain postural and repetitive motion data during MTKA and RATKA performed on cadavers. We assessed (1) flexion-extension at T3 and the occiput anatomical landmarks, (2) range of motion (ROM) as the percentage of time in the flexion-extension angle, (3) repetition rate, defined as the number of the times T3 and the occiput flexion-extension angle exceeded ±10°; and (4) static posture, where T3 or occiput postures exceed 10° for more than 30 seconds. The average T3 flexion-extension angle for MTKA cases was 5-degree larger than for RATKA cases (19 ± 8 vs. 14 ± 8 degrees). The surgeons who performed MTKA cases spent 15% more time in nonneutral C-spine ROM than those who performed RATKA cases (78 ± 25 vs. 63 ± 36%, p < 0.01). The repetition rate at T3 was 4% greater for MTKA than RATKA (14 ± 5 vs. 10 ± 6 reps/min). The percentage of time spent in static T3 posture was 5% greater for overall MTKA cases than for RATKA cases (15 ± 3 vs. 10 ± 3%). In this cadaveric study, we found differences in cervical and thoracic ergonomics between manual and robotic-assisted TKA. Specifically, we found that RATKA may reduce a surgeon's ergonomic strain at both the T3 and occiput locations by reducing the time the surgeon spends in a nonneutral position.

Comparison of LEBA and RULA Based on Postural Load Criteria and Epidemiological Data on Musculoskeletal Disorders

Various observational methods have been developed and applied in industrial settings with the aim of preventing musculoskeletal disorders (MSDs). This study aimed to compare the Rapid Upper Limb Assessment (RULA), a representative observational method, and the Loading on the Entire Body Assessment (LEBA), a newly developed tool for assessing postural loads and their association with MSDs. The two methods were compared in various categories, including general characteristics, risk levels, postural load criteria, association with MSDs, influencing factors, and inter- and intra-rater reliabilities based on relevant previous studies. The results showed that compared to the RULA, the LEBA was better at evaluating various factors affecting postural loads and assessing musculoskeletal loadings, was better correlated with various postural load criteria, could predict the association with MSDs more accurately, and had higher inter- and intra-rater reliabilities. Based on these comparisons, it seems that the LEBA may be better than the RULA for estimating postural stress and predicting the association with MSDs.

A RULA-Based Comparison of the Ergonomic Risk of Typical Working Procedures for Dentists and Dental Assistants of General Dentistry, Endodontology, Oral and Maxillofacial Surgery, and Orthodontics

BACKGROUND

In general, the prevalence of work-related musculoskeletal disorders (WMSD) in dentistry is high, and dental assistants (DA) are even more affected than dentists (D). Furthermore, differentiations between the fields of dental specialization (e.g., general dentistry, endodontology, oral and maxillofacial surgery, or orthodontics) are rare. Therefore, this study aims to investigate the ergonomic risk of the aforementioned four fields of dental specialization for D and DA on the one hand, and to compare the ergonomic risk of D and DA within each individual field of dental specialization.

METHODS

In total, 60 dentists (33 male/27 female) and 60 dental assistants (11 male/49 female) volunteered in this study. The sample was composed of 15 dentists and 15 dental assistants from each of the dental field, in order to represent the fields of dental specialization. In a laboratory setting, all tasks were recorded using an inertial motion capture system. The kinematic data were applied to an automated version of the Rapid Upper Limb Assessment (RULA).

RESULTS

The results revealed significantly reduced ergonomic risks in endodontology and orthodontics compared to oral and maxillofacial surgery and general dentistry in DAs, while orthodontics showed a significantly reduced ergonomic risk compared to general dentistry in Ds. Further differences between the fields of dental specialization were found in the right wrist, right lower arm, and left lower arm in DAs and in the neck, right wrist, right lower arm, and left wrist in Ds. The differences between Ds and DAs within a specialist discipline were rather small.

DISCUSSION

Independent of whether one works as a D or DA, the percentage of time spent working in higher risk scores is reduced in endodontologists, and especially in orthodontics, compared to general dentists or oral and maxillofacial surgeons. In order to counteract the development of WMSD, early intervention should be made. Consequently, ergonomic training or strength training is recommended.

Why cumulative loading calculated using non-weighted integration may not be suitable for assessing physical stress of the lower back: an empirical investigation of strain during lifting and lowering tasks

When work-related physical stress is assessed using non-weighted integration, it is assumed that different loading conditions have a sufficiently comparable effect on the human body as long as the area under the loading curve is the same. Growing evidence cast doubt on whether this simple calculation can adequately estimate physical work-related strain. This study investigates in vivo, focussing on the lower back, whether the non-weighted method adequately reflects work-related physical strain of the lower back. Strain data resulting from lifting/lowering tasks performed in a laboratory study with an identical area under the loading curve but different load intensities were compared. Results showed that the non-weighted method does not sufficiently reflect the resulting muscular, cardiovascular and perceived strain but underestimates the influence of higher load intensity even in the range of medium physical exposure. Further research is needed regarding the determination of weighting factors and limit values. Practitioner Summary Given the dynamic nature of most physical work activities, the assessment of time-varying loading of the lower back is of particular interest in practice. Results show that the widely used non-weighted calculation method does not accurately reflect the resulting physical strain but underestimates the influence of higher load intensity.Abbreviations: MSD: musculoskeletal disorders; WMSD: work-related musculoskeletal disorders; KIM-LHC: Key Indicator Method Lifting, Holding, Carrying; RES: right erector spinae longissimus; LES: left erector spinae longissimus; HR: heart rate; RPE: rating of perceived exertion; EMG: surface electromyography; ECG: electrocardiography; SENIAM: Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles; MVC: maximum voluntary contraction; ANOVA: analysis of variance; Std. error: standard error HIGHLIGHTSResults of this empirical investigation suggest that the widely used non-weighted calculation method is not fully suitable for calculating cumulative loading of the lower back.Even in the range of medium physical exposure the non-weighted calculation method does not accurately reflect the resulting strain on the human body but tends to underestimate the influence of higher load intensity due to higher external weight.Despite the same cumulative loading value obtained when using the non-weighted method, the resulting physical strain values are generally about 20-25% higher.The results may be used to further develop ergonomic assessment methods in order to avoid a misclassification of loading conditions and to prevent the risk of overexertion.

Machine Learning Model to Estimate Net Joint Moments during Lifting Task Using Wearable Sensors: A Preliminary Study for Design of Exoskeleton Control System

Accurately measuring the lower extremities and L5/S1 moments is important since L5/S1 moments are the principal parameters that measure the risk of musculoskeletal diseases during lifting. In this study, protocol that predicts lower extremities and L5/S1 moments with an insole sensor was proposed to replace the prior methods that have spatial constraints. The protocol is hierarchically composed of a classification model and a regression model to predict joint moments. Additionally, a single LSTM model was developed to compare with proposed protocol. To optimize hyperparameters of the machine learning model and input feature, Bayesian optimization method was adopted. As a result, the proposed protocol showed a relative root mean square error (rRMSE) of 8.06~13.88% while the single LSTM showed 9.30~18.66% rRMSE. This protocol in this research is expected to be a starting point for developing a system for estimating the lower extremity and L5/S1 moment during lifting that can replace the complex prior method and adopted to workplace environments. This novel study has the potential to precisely design a feedback iterative control system of an exoskeleton for the appropriate generation of an actuator torque.

Load Asymmetry Angle Estimation Using Multiple view Videos

A robust computer vision-based approach is developed to estimate the load asymmetry angle defined in the revised NIOSH lifting equation (RNLE). The angle of asymmetry enables the computation of a recommended weight limit for repetitive lifting operations in a workplace to prevent lower back injuries. An open-source package OpenPose is applied to estimate the 2D locations of skeletal joints of the worker from two synchronous videos. Combining these joint location estimates, a computer vision correspondence and depth estimation method is developed to estimate the 3D coordinates of skeletal joints during lifting. The angle of asymmetry is then deduced from a subset of these 3D positions. Error analysis reveals unreliable angle estimates due to occlusions of upper limbs. A robust angle estimation method that mitigates this challenge is developed. We propose a method to flag unreliable angle estimates based on the average confidence level of 2D joint estimates provided by OpenPose. An optimal threshold is derived that balances the percentage variance reduction of the estimation error and the percentage of angle estimates flagged. Tested with 360 lifting instances in a NIOSH-provided dataset, the standard deviation of angle estimation error is reduced from 10.13° to 4.99°. To realize this error variance reduction, 34% of estimated angles are flagged and require further validation.

Accuracy of a markerless motion capture system for postural ergonomic risk assessment in occupational practice

Established methods for postural ergonomic risk assessment in occupational practice are mostly time-consuming and need to be conducted by experts. Use of technology could improve postural ergonomic risk assessments with regard to time efficiency and accuracy. A study was conducted to assess the accuracy of a markerless motion capture system (Microsoft Kinect V2) compared to a marker-based motion capture system (Vicon Bonita). Angles of different body segments were analysed. The results show major inaccuracies of the markerless motion capture system for capturing axial trunk rotation (mean angular deviation of 14.04°) indicating that potential health risks could be underestimated. Combined working postures of axial trunk rotation and arm anteversion show issues with self-occlusion. Based on the findings, it is discussed whether the detected inaccuracies for axial trunk rotation are likely to lead to overestimation or underestimation of potential health risks when conducting an ergonomic risk assessment.

A PRELIMINARY ASSESSMENT OF PHYSICAL WORK EXPOSURES AMONG ELECTRONIC WASTE WORKERS AT AGBOGBLOSHIE, ACCRA GHANA

Occupational exposure associated with unstructured, informal e-waste recycling has received very limited attention. This study aimed to quantify the occupational physical exposures among informal e-waste workers at the largest e-waste site in Africa. A cross-sectional field survey of 163 male e-waste workers was conducted using a self-report occupational physical activity questionnaire, along with direct work observations, and pedometer estimates of walking activity for a subset of workers (n = 42). Results indicated significant differences in self-reported 7-day work exposures among the three main e-waste job categories, namely, collectors (n = 70), dismantlers (n = 73) and burners (n = 20). Prolonged walking, sitting and standing on five or more days in the workweek was frequently reported by collectors (87%), dismantlers (82%) and burners (60%), respectively. Nearly 90% of collectors and burners and 60% of dismantlers reported lifting and carrying on five or more days in the workweek. The exposure combinations identified suggest a risk for musculoskeletal disorders (MSDs). Findings call attention to the need for research examining potential associations between physical exposures and MSDs affecting e-waste workers in Agbogbloshie. The high exposure variability both between and within workers has implications for future exposure assessments conducted in unregulated, informal work settings.

Validity and reliability of the Persian version of the Quick Exposure Check (QEC) in Iranian construction workers

BACKGROUND: The Quick Exposure Check (QEC) is an instrument to identify occupational risk factors, and to screen subjects for the risk of musculoskeletal disorders in their workplace. OBJECTIVES: The aim of this prospective observational study was the cross-cultural adaptation of the QEC for Persian (QEC-Pr) speaking workers and the determination of the minimally required psychometric properties, including reliability and validity, in a Persian population. METHODS: The forward-backward translation was completed according to the published guidelines. A total of 217 male construction workers were recruited. The Rapid Upper Limb Assessment (RULA) tool was used as the criterion. The Inter- and intra-rater reliability was performed respectively in a sub-sample of n = 50 and n = 30. Convergent validity was determined from the correlation between the QEC-Pr and the RULA. Internal consistency was assessed using Cronbach’s α. RESULTS: High levels of inter-rater reliability (ICC2.1 range = 0.79–0.93), intra-rater reliability (ICC2.1 range = 0.74–0.89) and internal consistency (α= 0.74) were obtained. Concurrent validity between the different sections of the QEC and RULA scores were determined to be fair but below the desired level (range r = 0.41–0.44). CONCLUSIONS: The QEC-Pr can be applied as a specific risk assessment instrument for different occupational situations, such as the construction industry, in Persian language populations.

The Sensor-Based Biomechanical Risk Assessment at the Base of the Need for Revising of Standards for Human Ergonomics

Due to the epochal changes introduced by "Industry 4.0", it is getting harder to apply the varying approaches for biomechanical risk assessment of manual handling tasks used to prevent work-related musculoskeletal disorders (WMDs) considered within the International Standards for ergonomics. In fact, the innovative human-robot collaboration (HRC) systems are widening the number of work motor tasks that cannot be assessed. On the other hand, new sensor-based tools for biomechanical risk assessment could be used for both quantitative "direct instrumental evaluations" and "rating of standard methods", allowing certain improvements over traditional methods. In this light, this Letter aims at detecting the need for revising the standards for human ergonomics and biomechanical risk assessment by analyzing the WMDs prevalence and incidence; additionally, the strengths and weaknesses of traditional methods listed within the International Standards for manual handling activities and the next challenges needed for their revision are considered. As a representative example, the discussion is referred to the lifting of heavy loads where the revision should include the use of sensor-based tools for biomechanical risk assessment during lifting performed with the use of exoskeletons, by more than one person (team lifting) and when the traditional methods cannot be applied. The wearability of sensing and feedback sensors in addition to human augmentation technologies allows for increasing workers' awareness about possible risks and enhance the effectiveness and safety during the execution of in many manual handling activities.

Application of the Rapid Entire Body Assessment (REBA) in assessing chairside ergonomic risk of dental students

Introduction High prevalence of musculoskeletal disorders (MSDs) have been reported among operators in dentistry related to prolonged demanding and awkward operative tasks, in which non-neutral vertebral positions and risky joint articulations are adopted. The aim of the study was to investigate the feasibility and reliability of the application of the Rapid Entire Body Assessment (REBA) among dental students utilising three digital photographs of the operator to determine chairside ergonomic risk.Materials and methods Third-year dental students (n = 28) obtained profile, back and frontal digital photographs of student operators in a clinical session. REBA scorings were assigned per student utilising the photographs by student groups and independently by a physiotherapist. Statistical comparisons were done for both scorings.Results There was substantial interrater reliability (kappa = 0.625; p <0.001) and moderate concordance level (Kendall's Tau-b of 0.568; p <0.01) between the scores derived from students and staff. Medium- and high-risk students based on the REBA scores accounted for 64% and 75% of the class as determined by students and staff, respectively.Discussion The high percentage of medium-to-high-risk REBA values matched the prevalence of MSDs reported by dental students in the literature. Compared to staff, students with moderate reliability were able to produce REBA scores adequately.Conclusion REBA utilising digital photographs may be an easily applicable and moderately reliable tool for alerting static ergonomic risk for clinical dental students. Modification of at-risk behaviour early in training may limit the establishment of bad posture habits and aid in the prevention of MSDs during their clinical years and post-graduation.

Wearable Sensor Network for Biomechanical Overload Assessment in Manual Material Handling

The assessment of risks due to biomechanical overload in manual material handling is nowadays mainly based on observational methods in which an expert rater visually inspects videos of the working activity. Currently available sensing wearable technologies for motion and muscular activity capture enables to advance the risk assessment by providing reliable, repeatable, and objective measures. However, existing solutions do not address either a full body assessment or the inclusion of measures for the evaluation of the effort. This article proposes a novel system for the assessment of biomechanical overload, capable of covering all areas of ISO 11228, that uses a sensor network composed of inertial measurement units (IMU) and electromyography (EMG) sensors. The proposed method is capable of gathering and processing data from three IMU-based motion capture systems and two EMG capture devices. Data are processed to provide both segmentation of the activity and ergonomic risk score according to the methods reported in the ISO 11228 and the TR 12295. The system has been tested on a challenging outdoor scenario such as lift-on/lift-off of containers on a cargo ship. A comparison of the traditional evaluation method and the proposed one shows the consistency of the proposed system, its time effectiveness, and its potential for deeper analyses that include intra-subject and inter-subjects variability as well as a quantitative biomechanical analysis.

E-worker postural comfort in the third-workplace: An ergonomic design assessment

BACKGROUND

Biomechanical simulation is an important tool in human-centred design, allowing for the assessment of comfort interactions between user, product and space, to optimize design features from an ergonomics perspective.

OBJECTIVE

The aim of this study was to develop a biomechanical model for the evaluation of postural comfort levels.

METHODS

The study used the scenario-based method to focus on the electronic-worker (e-worker) sedentary tablet tasks at public workplace (third-workplace) configurations. An empirical method determined work-related musculoskeletal disorders (WMSDs) risk levels. The experimental method was based on a motion-capture marker-based laboratory protocol and biomechanical model. Body postures were analysed to determine the WMSDs risk to the joints, and were compared to subjective questionnaires.

RESULTS

Posture was affected by the tablet target location and workplace setting. The findings confirmed our hypothesis, that neutral-position cost functions govern human motion. Almost half of the time, the e-workers' joints tended to remain in the neutral position range; of the three third-workplaces, high-risk variability was less significant between the 'restaurant' and 'lounge' settings, compared to the 'anywhere' configuration.

CONCLUSIONS

This evaluation model can contribute to optimizing comfort level in design for third-workplace settings and other sedentary work activities; it can be used to develop guidelines for minimizing work-related strain and health hazards.

Standardized photometric assessment method: A novel approach for the analysis of dental ergonomic posture

Background:

Identification and documentation of the proper and improper dental ergonomic postures have gained its importance in the recent years due to the increased prevalence of work-related musculoskeletal disorders (WMSDs) among dentists and dental students who do not practice proper ergonomic procedure.

Aim:

The aim of the present study is to analysis ergonomic posture among dental students while performing supragingival scaling (SGS) procedure, using the standardized photometric assessment method (SPAM).

Materials and Methods:

A total number of 90 students from the third year (III year) to final year (IV year) and internship (Intern) (30 each) were included in the study. All the 90 students were asked to perform SGS procedure and were photographed and analyzed using the current technique. Eight dental ergonomic postures were analyzed in this study and grouped according to the classification system developed for scoring dental ergonomic postures by Garbin et al., in 2011. Analysis of variance test with Bonferroni correction was used to statistically analyze the collected data.

Results:

The mean index value for III year, IV year and Intern were 2.00, 2.03, and 2.13, respectively, which was not statistically significant (P = 0.709).

Conclusions:

Analysis of the dental students using the current method showed that most of them come under inadequate and regular category which puts them in a high risk for developing WMSDs. The SPAM to analyze the dental ergonomic posture was simple and effective and should be further explored in the future studies for its pros and cons.

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.

Feasibility of quantifying the physical exposure of materials handlers in the workplace with magnetic and inertial measurement units

Handling tasks can expose workers to risk factors. The objective was to describe the feasibility of using magnetic and inertial measurement units (MIMUs) to quantify the physical exposure of materials handlers in the workplace. Full-body kinematics were obtained with MIMUs on 10 handlers gathering products ordered by retailers with a pallet truck. An observer classified the visual difference (VD) of segment orientation between a MIMUs avatar and video recordings in three categories (none, minor and major) for each product transfer. The feet, arms, shoulders and head were considered similar for ≥97% of observations. The trunk segment obtained the most differences with 9% of minor VD and 5% of major VD, which were related to the duration of the magnetic disturbances of the MIMUs. Estimating parameters of the physical exposure of handlers in the workplace is feasible with kinematics and an order list, but visual verification remains important for scientific rigour.Practitioner Summary: The feasibility of measuring physical exposure with magnetic and inertial measurement units was evaluated on materials handlers in the workplace. Visual observation of the postures indicated that most of the data is considered acceptable. Magnetic disturbances can increase the measurement error, so data must be verified to ensure validity.

A structural framework for sustainable processes in ergonomics

Considering today's globalised world, new concepts that assist ergonomics are needed to provide human well-being. Accordingly, the sustainability concept is used in this study to satisfy the needs of stakeholders, put environmentally-friendly and cost-effective interventions into practice and provide ergonomically well-designed and easily managed processes that are more flexible, adaptable and human-sensitive. To achieve this, a practical and easily adaptable framework, which integrates ergonomics and sustainability by presenting the relations between fundamental elements of ergonomics and sustainability dimensions (SDs), is proposed. Within this base framework, ergonomic indicators (EIs) and sub-dimensions proposed for the classification of EIs are structured for ergonomics under a sustainability point-of-view. The sub-dimensions proposed in this study, which have direct or indirect relations to humans, are 'Loss', 'Investment', 'Conditions', 'Contribution', 'Self-Development', and 'Satisfaction'. This structural framework, which can be easily used by ergonomists or managers, ensures a good starting point for providing sustainable processes in ergonomics. Practitioner summary: This study proposes a structural framework to present the relations between ergonomics and sustainability. In the context of ergonomics, fundamental elements of ergonomics are chosen, while three dimensions of sustainability and proposed sub-dimensions are used in the context of sustainability. The adapted ergonomic indicators are also classified within these sub-dimensions.Abbreviations: SDs: sustainability dimensions; SIs: sustainability indicators; EIs: ergonomic indicators.

Work-related Musculoskeletal Symptoms among Agricultural Workers: A Cross-sectional Study in Iran

Objective: In Iran, as in most developing countries, agriculture is considered a hazardous industry. Musculoskeletal disorders (MSD) have been shown to be the most common occupational injury among farmers. The present study was carried out among agricultural workers of Fars province, Iran to determine the prevalence of musculoskeletal symptoms and to assess working postures and ergonomic working conditions to identify the major risk factors associated with MSD. Methods: This cross-sectional study was conducted on 1501 randomly selected Iranian agricultural workers with at least 1 year of job tenure. Data were collected using demographic/occupational questionnaire, Nordic Musculoskeletal Questionnaire (NMQ), Quick Exposure Check (QEC) technique, and ergonomic working conditions checklist. Results: The mean age of the participants was 41.39 ± 13.64 years. The results of NMQ showed the highest prevalence of MSD symptoms was related to lower back (59.3%), knees (36.9%), and upper back (36.6%). Indeed, the QEC score was high or very high (action levels 3 and 4) in 83.1% of the farmers. Moreover, the ergonomic working conditions checklist revealed that the participants' "working postures" index had the lowest mean, indicating poor ergonomic conditions, while "hand tools" had the highest mean, indicating proper ergonomic conditions. Conclusions: The results demonstrated the high prevalence of MSD symptoms among Iranian agricultural workers. Elimination of harmful working postures was recommended to improve working conditions.

Whole body biomechanical burden of healthcare workers: proposal for a complementary risk assessment and management tool (HOARA)

Introduction:

We have developed a new tool, named Holistic Approach Risk Assessment (HOARA), to support occupational safety and health professionals (OSH) in risk assessment and management when evaluating the biomechanical load of healthcare workers.

Objectives:

The primary aim of the HOARA is to support OSH in risk assessment and management of biomechanical hazards in healthcare facilities. This tool ensures a superior level of analysis by targeting independently various body compartments during all activities completed throughout the work shift. These include: head, neck, back and upper and lower limbs.

Methods:

For each body segment, ergonomic determinants were defined on the basis of previous literature, according to which task and job analyses were performed. Upon direct observation, ergonomic factors were given a score based on their temporal extent. Subsequently, action-body segment raw indices and weighted indices were calculated.

Results:

Results of the application of the method are shown. Of note, a relational database was set up to improve its usability.

Conclusions:

From an occupational health perspective, the HOARA, integrated with other methods, is expected to allow a more effective management of human resources, especially when assigning workers to specific jobs or tasks. Overall, the HOARA will be instrumental in assessing the impact of fitness for work judgments on work organization and its resources, in compliance with the guidelines from the Società Italiana di Medicina del Lavoro (SIML).

The accuracy of a 2D video-based lifting monitor

A widely used risk prediction tool, the revised NIOSH lifting equation (RNLE), provides the recommended weight limit (RWL), but is limited by analyst subjectivity, experience, and resources. This paper describes a robust, non-intrusive, straightforward approach to automatically extract spatial and temporal factors necessary for the RNLE using a single video camera in the sagittal plane. The participant's silhouette is segmented by motion information and the novel use of a ghosting effect provides accurate detection of lifting instances, and hand and feet location prediction. Laboratory tests using 6 participants, each performing 36 lifts, showed that a nominal 640 pixel × 480 pixel 2D video, in comparison to 3D motion capture, provided RWL estimations within 0.2 kg (SD = 1.0 kg). The linear regression between the video and 3D tracking RWL was R² = 0.96 (slope = 1.0, intercept = 0.2 kg). Since low definition video was used in order to synchronise with motion capture, better performance is anticipated using high definition video. Practitioner's summary: An algorithm for automatically calculating the revised NIOSH lifting equation using a single video camera was evaluated in comparison to laboratory 3D motion capture. The results indicate that this method has suitable accuracy for practical use and may be, particularly, useful when multiple lifts are evaluated. Abbreviations: 2D: Two-dimensional; 3D: Three-dimensional; ACGIH: American Conference of Governmental Industrial Hygienists; AM: asymmetric multiplier; BOL: beginning of lift; CM: coupling multiplier; DM: distance multiplier; EOL: end of lift; FIRWL: frequency independent recommended weight limit; FM: frequency multiplier; H: horizontal distance; HM: horizontal multiplier; IMU: inertial measurement unit; ISO: International Organization for Standardization; LC: load constant; NIOSH: National Institute for Occupational Safety and Health; RGB: red, green, blue; RGB-D: red, green, blue - depth; RNLE: revised NIOSH lifting equation; RWL: recommended weight limit; SD: standard deviation; TLV: threshold limit value; VM: vertical multiplier; V: vertical distance.

Evaluation of a proposed chair with an arm support for wiring terminal blocks on a vertical plane

To reduce the muscular exertion of an operator wiring terminal blocks on a vertical plane, a chair with a unique back that can be used as a back support or arm support is proposed in this study. A digital version of the chair was first developed based on anthropometric data and tested with a digital anthropometric subject using the Jack software before the physical chair was developed. To evaluate the effects of the physical chair, an experiment of wiring terminal blocks was conducted with 12 subjects to test whether the use of the arm support can reduce muscular exertion. The results showed that (1) exertion on the anterior deltoid, upper trapezium, and erector spinae muscles decreased with decrease in terminal block height; (2) using the arm support reduced exertion on the anterior deltoid and upper trapezium muscles; and (3) the subjects reported less self-perceived fatigue in the wrist, elbow, and shoulder regions when the arm support was used. These results confirm that the proposed chair can reduce muscular workload in the shoulder muscle over a proper range of working heights. However, using the arm support may restrict certain working postures and lead to force generation in upper extremity muscles.

Work-related Musculoskeletal Disorders in Iranian Office Workers: Prevalence and Risk Factors

Objective: This study aimed to identify the prevalence of musculoskeletal disorders (MSDs) and ergonomic risks for Kerman University of Medical Sciences’ office workers.

Methods: The study sample comprised all office workers in the University and the sample included 129 women and 121 men. Data on MSDs were derived from the Nordic Musculoskeletal Questionnaire, while ergonomic data were collected through two direct observations via the rapid upper limb assessment (RULA) and the rapid office strain assessment (ROSA) method.

Results: The results showed that the highest prevalence rates of MSDs were in the lower back (72.4%) and neck (55.2). Results of the postural assessment revealed that 68.8% of the participants’ require “further investigation in order to modify their posture” and 27.6% need to “modify their posture soon.” From the workstation analysis, the majority of the office workers were at a medium (55.2%) and high-risk level (27.6%). Results also revealed a significant association between some of MSDs in the lower back and neck with the RULA and ROSA score.

Conclusions: Based on the results, for the prevention of MSDs, there should be ergonomics workshops for workers to be aware of ergonomics factors in the office. The ergonomics training must also be used in offices; the design of workstations should be improved.

Evaluation of physiological workload assessment methods using heart rate and accelerometry for a smart wearable system

Work metabolism (WM) can be accurately estimated by oxygen consumption (VO₂), which is commonly assessed by heart rate (HR) in field studies. However, the VO₂-HR relationship is influenced by individual capacity and activity characteristics. The purpose of this study was to evaluate three models for estimating WM compared with indirect calorimetry, during simulated work activities. The techniques were: the HR-Flex model; HR branched model, combining HR with hip-worn accelerometers (ACC); and HR + arm-leg ACC model, combining HR with wrist- and thigh-worn ACC. Twelve participants performed five simulated work activities and three submaximal tests. The HR + arm-leg ACC model had the overall best performance with limits of agreement (LoA) of -3.94 and 2.00 mL/min/kg, while the HR-Flex model had -5.01 and 5.36 mL/min/kg and the branched model, -6.71 and 1.52 mL/min/kg. In conclusion, the HR + arm-leg ACC model should, when feasible, be preferred in wearable systems for WM estimation. Practitioner Summary: Work with high energy demand can impair employees' health and life quality. Three models were evaluated for estimating work metabolism during simulated tasks. The model combining heart rate, wrist- and thigh-worn accelerometers showed the best accuracy. This is, when feasible, suggested for wearable systems to assess work metabolism.

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.

Investigation of observational methods assessing workload of static working postures based on surface electromyography

BACKGROUND:

A large number of different methods are available to identify and assess working postures. Although observation-based methods are most commonly used in practise, investigations showed different results regarding validity of such methods.

OBJECTIVE:

To investigate validity of one of the most commonly used observation-based assessment method in ergonomics, the Ovako Working Posture Analysing System (OWAS) and the European standard EN 1005-4 for evaluation of working postures, an experimental laboratory study was conducted.

METHODS:

Muscle activity was measured under combinations of static working postures of trunk inclination and shoulder flexion to compare these measurements and observation-based assessments according to OWAS and EN 1005-4. In order to investigate the magnitude of correspondence between muscle activity and observation-based assessments, Spearman rank correlation coefficients (r_s) were calculated.

RESULTS:

Significant correlations were found between OWAS and muscle activity (range from r_s² = 0.17 r_s² = 0.55). Significant correlations were found between EN 1005-4 and muscle activity (range from r_s² = 0.34 to r_s² = 0.74).

CONCLUSIONS:

Results emphasise a need for further developments of observation-based methods, since the two investigated methods showed a variance of validity ranging from small to large. Such improvements may also form a better basis for the ergonomic improvement of working conditions in practise, which is highly necessary due to a constantly high prevalence of MSDs in the last decades.

Integrating a Resilience Scorecard and Landscape Performance into a Geodesign Process

Uncertainty about the impacts of sea level rise make the ability to forecast future spatial conditions a necessary planning/design tool. Geodesign integrates multiple fields of science with change/impact models and planning/design strategies. Proactive planning analyses such as newly developed scorecards allow for plan evaluation; design strategies can now be quantitatively assessed using landscape performance calculators. Neither have been explored as Geodesign tools. A Geodesign process was developed using the resilience scorecard to assess flood vulnerability using projections for the 100 year floodplain with sea level rise by 2100. Projections were used as a guide to develop a resilient master plan for League City, TX, USA. Future impacts of the plan are projected using landscape performance measures.

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.