Validity of the modified RULA for computer workers and reliability of one observation compared to six

Ergonomic investigations on novel dynamic postural estimator using blaze pose and transfer learning

The aim is to develop a computer-based assessment model for novel dynamic postural evaluation using RULA. The present study proposed a camera-based, three-dimensional (3D) dynamic human pose estimation model using 'BlazePose' with a data set of 50,000 action-level-based images. The model was investigated using the Deep Neural Network (DNN) and Transfer Learning (TL) approach. The model has been trained to evaluate the posture with high accuracy, precision, and recall for each output prediction class. The model can quickly analyse the ergonomics of dynamic posture online and offline with a promising accuracy of 94.12%. A novel dynamic postural estimator using blaze pose and transfer learning is proposed and assessed for accuracy. The model is subjected to a constant muscle loading factor and foot support score that could evaluate one person with good image clarity at a time.Practitioner summary: A detailed investigation of dynamic work postures is largely missing in the literature. Experimental analysis has been performed using transfer learning, BlazePose, and RULA action levels. An overall accuracy of 94.12% is achieved for dynamic postural assessment.

Testing the Level of Agreement between Two Methodological Approaches of the Rapid Upper Limb Assessment (RULA) for Occupational Health Practice-An Exemplary Application in the Field of Dentistry

BACKGROUND

The Rapid Upper Limb Assessment (RULA) is used for the risk assessment of workplace-related activities. Thus far, the paper and pen method (RULA-PP) has been predominantly used for this purpose. In the present study, this method was compared with an RULA evaluation based on kinematic data using inertial measurement units (RULA-IMU). The aim of this study was, on the one hand, to work out the differences between these two measurement methods and, on the other, to make recommendations for the future use of the respective method on the basis of the available findings.

METHODS

For this purpose, 130 (dentists + dental assistants, paired as teams) subjects from the dental profession were photographed in an initial situation of dental treatment and simultaneously recorded with the IMU system (Xsens). In order to compare both methods statistically, the median value of the difference of both methods, the weighted Cohen's Kappa, and the agreement chart (mosaic plot) were applied.

RESULTS

In Arm and Wrist Analysis-area A-here were differences in risk scores; here, the median difference was 1, and the agreement in the weighted Cohen's kappa test also remained between 0.07 and 0.16 (no agreement to poor agreement). In area B-Neck, Trunk, and Leg Analysis-the median difference was 0, with at least one poor agreement in the Cohen's Kappa test of 0.23-0.39. The final score has a median of 0 and a Cohen's Kappa value of 0.21-0.28. In the mosaic plot, it can be seen that RULA-IMU had a higher discriminatory power overall and more often reached a value of 7 than RULA-PP.

CONCLUSION

The results indicate a systematic difference between the methods. Thus, in the RULA risk assessment, RULA-IMU is mostly one assessment point above RULA-PP. Therefore, future study results of RULA by RULA-IMU can be compared with literature results obtained by RULA-PP to further improve the risk assessment of musculoskeletal diseases.

Usefulness of the Rapid Office Strain Assessment (ROSA) tool in detecting differences before and after an ergonomics intervention

Background

Most ergonomics studies on office workstations evaluate the effects of an intervention only by subjective measures such as musculoskeletal pain and discomfort. Limited evidence has been provided regarding risk factor reduction in office environments through standardized methods assessments. The Rapid Office Strain Assessment (ROSA) tool can provide an estimation of risk factor exposure for office workers as a means by which the outcome of interventions can be quantified.

Purpose

The aim of the study was to evaluate if ROSA scores reflect changes in risk factors after an ergonomics intervention among office workers.

Methods

Office workers (n = 60) were divided into two groups. The experimental group received a workstation intervention and the control group received no intervention. Changes in ROSA scores were compared before and after the intervention in both groups.

Results

Statistically significant reductions in the ROSA final and section scores occurred after the intervention in the experimental group with (mean reduction of 2.9, 0.8 and 1.6 points for sections A, B and C, respectively). In contrast, no differences were detected in the control group (mean increase of 0.1 point for sections A and C and mean reduction of 0.1 point for Section B).

Conclusions

These findings show that ROSA scores reflect changes in risk factors after an ergonomics intervention in an office environment. Consequently, this tool can be used for identifying and controlling risk factors among computer workers, before and after interventions.

Measuring pandemic home-work conditions to determine ergonomic recommendation relevance

BACKGROUND

Computer-intensive office work associations with health challenges may intensify following COVID-19 pandemic-related changes to home-based office work.

OBJECTIVE

To determine working conditions, perception and physical elements affecting health after pivoting to full time home-work.

METHODS

An online questionnaire addressed physical, productivity, motivation, and work-practice factors. Photos of the worker in their home-work environment showed side and front-back perspectives.

RESULTS

Sixteen questionnaires were received, and 12 respondents supplied photos. Home and office workplace differences varied. Ten felt productivity was affected, most often positively. Four noted increased pain or fatigue intensity, particularly in the eyes, neck / head, lower back, and shoulders. Working posture was not optimal; six didn't use traditional chair-sitting for up to half the day. Forward and backward trunk inclination accounted for at least 10% of the workday for 12 respondents; lateral inclination affected ten and eight had unsupported legs. Fifteen used an adjustable chair, but photos revealed ergonomic recommendations were not consistently followed. Fourteen participants communicated regularly by telephone, eight only for moderate duration and ten using adapted telephone equipment. Half of the ROSA scores were high.

CONCLUSIONS

Workers forced into telework during the pandemic experience positive and negative impacts. Postures vary more than in offices, potentially increasing health risk.

Risk factors associated with work-related musculoskeletal disorders among floor-sitting precision handicraft workers

PURPOSE

Precision handicraft workers are often exposed to stressful postures and poor working conditions while performing different jobs, that are directly associated with the development of musculoskeletal disorders (MSDs). This cross-sectional study aimed at evaluating the prevalence of MSDs and contributing risk factors among male precision handicraft workers.

METHODS

334 handicraft workers involved in different precision activities: 125 gemstone cutters, 98 miniature painters, and 111 metal craft workers, were surveyed. Information about the prevalence of musculoskeletal symptoms and work-related factors was collected using the self-reported questionnaire and direct observation methods, viz. rapid upper limb assessment (RULA) and rapid entire body assessment (REBA). Chi-square test was performed to analyze the association of MSD symptoms between the handicraft occupations. Further, binary logistic regression was used to identify the potential risk factors for MSD symptoms among workers.

RESULTS

In all occupational groups, most participants reported high prevalence of MSDs primarily in the neck (61.6%), lower back (74.8%), and knee (54.7%) regions. Results revealed that age, work experience, prolonged work hours, sustained awkward posture, continuous work without break, extensive work pressure, and poor job control increased the risk of MSD symptoms in different body regions, while with a higher level of education, MSDs in the neck and lower back regions reduced.

CONCLUSION

The findings indicated incompatibility between precision handicraft workers and the occupational environment. Logistic regression models showed significant contribution of physical and psychosocial work-related factors in developing MSD symptoms. Ergonomic interventions are imperative to evade adverse consequences on the occupational health of precision craft workers.

Musculoskeletal Risks: RULA Bibliometric Review

The objective of this study was to reveal RULA method applications in terms of the knowledge, country, year and journal categories. The search was performed using the "Web of Science Core Collection". The period from 1993 to April 2019 was selected. Eight hundred nine results were obtained, of which 226 were used. The largest number of publications was determined to be in the fields of industry and health and social assistance, which coincides with the OWAS and Standardized Nordic Questionnaire methods. By country, the USA stands out for its greater number of research studies and categories that are encompassed. By date, 2016 was the year when more studies were carried out, again coinciding with the Standardized Nordic Questionnaire. By journal, "Work-A Journal of Prevention Assessment and Rehabilitation" is highlighted, as it is for the REBA method as well. It was concluded that RULA can be applied to workers in different fields, usually in combination with other methods, while technological advancement provides benefits for its application.

Assessment of the ergonomic risk from saddle and conventional seats in dentistry: A systematic review and meta-analysis

Objective

This study aimed to verify whether the saddle seat provides lower ergonomic risk than conventional seats in dentistry.

Methods

This review followed the PRISMA statement and a protocol was created and registered in PROSPERO (CRD42017074918). Six electronic databases were searched as primary study sources. The "grey literature" was included to prevent selection and publication biases. The risk of bias among the studies included was assessed with the Joanna Briggs Institute Critical Appraisal Tool for Systematic Reviews. Meta-analysis was performed to estimate the effect of seat type on the ergonomic risk score in dentistry. The heterogeneity among studies was assessed using I² statistics.

Results

The search resulted in 3147 records, from which two were considered eligible for this review. Both studies were conducted with a total of 150 second-year dental students who were starting their laboratory activities using phantom heads. Saddle seats were associated with a significantly lower ergonomic risk than conventional seats [right side (mean difference = -3.18; 95% CI = -4.96, -1.40; p < 0.001) and left side (mean difference = -3.12; 95% CI = -4.56, -1.68; p < 0.001)], indicating posture improvement.

Conclusion

The two eligible studies for this review provide moderate evidence that saddle seats provided lower ergonomic risk than conventional seats in the examined population of dental students.

Physical risk factors identification based on body sensor network combined to videotaping

The aim of this study was to perform an ergonomic analysis of a material handling task by combining a subtask video analysis and a RULA computation, implemented continuously through a motion capture system combining inertial sensors and electrogoniometers. Five workers participated to the experiment. Seven inertial measurement units, placed on the worker's upper body (pelvis, thorax, head, arms, forearms), were implemented through a biomechanical model of the upper body to continuously provide trunk, neck, shoulder and elbow joint angles. Wrist joint angles were derived from electrogoniometers synchronized with the inertial measurement system. Worker's activity was simultaneously recorded using video. During post-processing, joint angles were used as inputs to a computationally implemented ergonomic evaluation based on the RULA method. Consequently a RULA score was calculated at each time step to characterize the risk of exposure of the upper body (right and left sides). Local risk scores were also computed to identify the anatomical origin of the exposure. Moreover, the video-recorded work activity was time-studied in order to classify and quantify all subtasks involved into the task. Results showed that mean RULA scores were at high risk for all participants (6 and 6.2 for right and left sides respectively). A temporal analysis demonstrated that workers spent most part of the work time at a RULA score of 7 (right: 49.19 ± 35.27%; left: 55.5 ± 29.69%). Mean local scores revealed that most exposed joints during the task were elbows, lower arms, wrists and hands. Elbows and lower arms were indeed at a high level of risk during the total time of a work cycle (100% for right and left sides). Wrist and hands were also exposed to a risky level for much of the period of work (right: 82.13 ± 7.46%; left: 77.85 ± 12.46%). Concerning the subtask analysis, subtasks called 'snow thrower', 'opening the vacuum sealer', 'cleaning' and 'storing' have been identified as the most awkward for right and left sides given mean RULA scores and percentages of time spent at risky levels. Results analysis permitted to suggest ergonomic recommendations for the redesign of the workstation. Contributions of the proposed innovative system dedicated to physical ergonomic assessment are further discussed.