Optimising computer vision-based ergonomic assessments: sensitivity to camera position and monocular 3D pose model.

Numerous computer vision algorithms have been developed to automate posture analysis and enhance the efficiency and accuracy of ergonomic evaluations. However, the most effective algorithm for conducting ergonomic assessments remains uncertain. Therefore, the aim of this study was to identify the optimal camera position and monocular 3D pose model that would facilitate precise and efficient ergonomic evaluations. We evaluated and compared four currently available computer vision algorithms: Mediapipe BlazePose, VideoPose3D, 3D-pose-baseline, and PSTMO to determine the most suitable model for conducting ergonomic assessments. Based on the findings, the side camera position yielded the lowest Mean Absolute Error (MAE) across static, dynamic, and combined tasks. This positioning proved to be the most reliable for ergonomic assessments. Additionally, VP3D_FB demonstrated superior performance among evaluated models.Practitioner Summary: This study aimed to determine the most effective computer vision algorithm and camera position for precise and efficient ergonomic evaluations. Evaluating four algorithms, we found that the side camera position with VideoPose3D yielded the lowest Mean Absolute Error (MAE), ensuring precise and efficient evaluations.

Effect of day time on smartphone use posture and related musculoskeletal disorders risk: a survey among university students.

BACKGROUND: Musculoskeletal disorders (MSDs) are one of the most important problems among young smartphone users worldwide. Portability leads to a wide variety of postures during the different activities of the day. The objective evaluation of these postures coupled with ergonomic tools allows evaluating the level of MSD risk to which users are exposed. METHODS: The purpose was to investigate the effect of the time of day on the posture adopted during smartphone use among university students. The study was conducted through a cross-sectional survey of 263 university sports students. Four time of day, i.e. morning, afternoon, evening and night, and a taxonomy of 41 postures called SmarTaxo were considered. SmarTaxo included 18 sitting, 11 standing, 10 lying and 2 walking postures and their ergonomic score. After checking the normality of the data, a non-parametric Kruskal-Wallis test was used to study the effect of the time of day on the use duration of the different postures. RESULTS: The total mean duration use per typical weekday was 5.39 ± 2.19 h for males and 5.15 ± 1.60 h for females with maximal duration during evening. The average smartphone use durations were statistically longer in afternoon and evening for all sitting (9.44 and 9.22 min respectively, p < 0.05) and calling (3.38 and 3.33 min respectively, p < 0.05) postures. The longest duration for standing postures was recorded for afternoon (8.91 min, p < 0.05). The lying postures were significantly more present in evening (19.36 min). Some postures were more used during a time of day. The side-lying posture was used more in evening and has an ergonomic score of 6, i.e. a high MSD risk. CONCLUSIONS: The survey showed that users are exposed to MSDs regardless of posture and time of day. Sitting postures are used more in the morning and afternoon while lying postures are used more in the evening. As long as the rate of use is so high (> 5 h per day), young people will remain highly exposed to MSDs.

Biomechanical Load of Neck and Lumbar Joints in Open-Surgery Training.

The prevalence of musculoskeletal symptoms (MSS) like neck and back pain is high among open-surgery surgeons. Prolonged working in the same posture and unfavourable postures are biomechanical risk factors for developing MSS. Ergonomic devices such as exoskeletons are possible solutions that can reduce muscle and joint load. To design effective exoskeletons for surgeons, one needs to quantify which neck and trunk postures are seen and how much support during actual surgery is required. Hence, this study aimed to establish the biomechanical profile of neck and trunk postures and neck and lumbar joint loads during open surgery (training). Eight surgical trainees volunteered to participate in this research. Neck and trunk segment orientations were recorded using an inertial measurement unit (IMU) system during open surgery (training). Neck and lumbar joint kinematics, joint moments and compression forces were computed using OpenSim modelling software and a musculoskeletal model. Histograms were used to illustrate the joint angle and load distribution of the neck and lumbar joints over time. During open surgery, the neck flexion angle was 71.6% of the total duration in the range of 10~40 degrees, and lumbar flexion was 68.9% of the duration in the range of 10~30 degrees. The normalized neck and lumbar flexion moments were 53.8% and 35.5% of the time in the range of 0.04~0.06 Nm/kg and 0.4~0.6 Nm/kg, respectively. Furthermore, the neck and lumbar compression forces were 32.9% and 38.2% of the time in the range of 2.0~2.5 N/kg and 15~20 N/kg, respectively. In contrast to exoskeletons used for heavy lifting tasks, exoskeletons designed for surgeons exhibit lower support torque requirements while additional degrees of freedom (DOF) are needed to accommodate combinations of neck and trunk postures.

Predicting Wrist Posture during Occupational Tasks Using Inertial Sensors and Convolutional Neural Networks.

Current methods for ergonomic assessment often use video-analysis to estimate wrist postures during occupational tasks. Wearable sensing and machine learning have the potential to automate this tedious task, and in doing so greatly extend the amount of data available to clinicians and researchers. A method of predicting wrist posture from inertial measurement units placed on the wrist and hand via a deep convolutional neural network has been developed. This study has quantified the accuracy and reliability of the postures predicted by this system relative to the gold standard of optoelectronic motion capture. Ten participants performed 3 different simulated occupational tasks on 2 occasions while wearing inertial measurement units on the hand and wrist. Data from the occupational task recordings were used to train a convolutional neural network classifier to estimate wrist posture in flexion/extension, and radial/ulnar deviation. The model was trained and tested in a leave-one-out cross validation format. Agreement between the proposed system and optoelectronic motion capture was 65% with κ = 0.41 in flexion/extension and 60% with κ = 0.48 in radial/ulnar deviation. The proposed system can predict wrist posture in flexion/extension and radial/ulnar deviation with accuracy and reliability congruent with published values for human estimators. This system can estimate wrist posture during occupational tasks in a small fraction of the time it takes a human to perform the same task. This offers opportunity to expand the capabilities of practitioners by eliminating the tedium of manual postural assessment.

Musculoskeletal disorders risk assessment methods: a scoping review from a sex perspective.

The evidence points to differences in the impact of musculoskeletal disorders (MSD) in males and females due to different exposure to risk factors and inherent characteristics. To identify risks associated with MSDs, ergonomic assessment is carried out by applying various methods. The aim of this scoping review was to determine to what extent ergonomic assessment methods consider sex-related factors and if they were found to do so, to determine the extent of this consideration. A total of 31 papers on 32 ergonomic assessment methods were analysed in the review. Of these 32 methods, only 6 considered sex as an assessment parameter or when interpreting the results. The results revealed that the limited consideration given to the sex factor in ergonomic methods, together with the different impacts of MSDs and their consequences according to a person's sex, supports the importance of including sex factors in ergonomic assessment methods. Practitioner summary: This scoping review determined to what extent ergonomic assessment methods consider sex-related factors and if they do so, to establish the extent of such consideration. Of the 32 methods analysed, only 6 considered a person's sex. The results revealed that only a limited consideration is given to the sex factor in ergonomic methods.

Development and validation of a Nurse Station Ergonomics Assessment (NSEA) tool.

BACKGROUND: Nurse stations are one of the primary units for supporting effective functioning of any hospital. They are important working environments that demand adherence to known ergonomic principles for the well-being of both staff and patients. The aim of this study was to develop a psychometrically tested tool for the assessment of the ergonomic conditions of nurse workstations in hospitals. METHODS: Ten hospitals, with a total of 133 nurse stations participated in this mixed-methods research. The domains and items of the tool were developed based on a literature review, an experts' panel, and interviews with nurses. RESULTS: The final nurse station ergonomic assessment (NSEA) tool has good psychometric properties. Validity was assessed by face validity and content validity. Reliability was evaluated using inter-rater agreement and test-retest reliability analyses with a four-week interval between assessments. The NSEA is comprised of 64 items across eight domains: layout and location (7 items), workspace (11 items), security-safety (5 items), environmental conditions (8 items), counter (8 items), chair (13 items), desk (9 items), and monitor (3 items). CONCLUSIONS: The NSEA adds to the literature a tool for managers to ensure they comply with legal requirements and support best practice for those working on hospital wards. The NSEA can be used to identify challenges for healthcare professionals who use nurse stations and support the execution of targeted interventions to improve human-environment interactions.

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.

An Online Method to Detect and Locate an External Load on the Human Body with Applications in Ergonomics Assessment.

In this work, we propose an online method to detect and approximately locate an external load induced on the body of a person interacting with the environment. The method is based on a torque equilibrium condition on the human sagittal plane, which takes into account a reduced-complexity model of the whole-body centre of pressure (CoP) along with the measured one, and the vertical component of the ground reaction forces (vGRFs). The latter is combined with a statistical analysis approach to improve the localisation accuracy, (which is subject to uncertainties) to the extent of the industrial applications we target. The proposed technique eliminates the assumption of known contact position of an external load on the human limbs, allowing a more flexible online body-state tracking. The accuracy of the proposed method is first evaluated via a simulation study in which various contact points on different body postures are considered. Next, experiments on human subjects with three different contact locations applied to the human body are presented, revealing the validity of the proposed methodology. Lastly, its benefit in the estimation of human dynamic states is demonstrated. These results add another layer to the online human ergonomics assessment framework developed in our laboratory, extending it to more realistic and varying interaction conditions.

Equivalent weight: Application of the assessment method on real task conducted by railway workers wearing a back support exoskeleton.

Commonly used risk indexes, such as the NIOSH Lifting Index, do not capture the effect of exoskeletons. This makes it difficult for Health and Safety professionals to rigorously assess the benefit of such devices. The community requires a simple method to assess the effectiveness of back-support exoskeleton's (BSE) in possibly reducing ergonomic risk. The method introduced in this work is termed "Equivalent Weight" (EqW) and it proposes an interpretation of the effect built on the benefit delivered through reduced activation of the erector spinae (ES). This manifests itself as an apparent reduction of the lifted load perceived by the wearer. This work presents a pilot study where a practical application of the EqW method is used to assess the ergonomic risk in manual material handling (MMH) when using a back support exoskeleton (StreamEXO). The results are assessed by combining observational measurements from on-site testing with five different workers and quantitative measures of the muscle activity reduction achieved during laboratory evaluation with ten workers. These results will show that when lifting, lowering, and carrying a 19 kg load the StreamEXO can reduce risk by up to two levels (from "high" to "low") in the target sub-tasks. The Lifting index (LI) was reduced up to 64% when examining specific sub-tasks and the worker's movement conduction.

Work-Related Musculoskeletal Disorders Risk Assessment during Manual Lymphatic Drainage with Compressive Bands among Physiotherapists.

BACKGROUND: Complete decongestive therapy is the standard treatment for lymphedema. Manual lymphatic drainage and short-stretch multilayer compression bandaging are two daily stages of complete decongestive therapy during which physiotherapists work with patients. OBJECTIVE: The aim of this study was to assess the risks of musculoskeletal disorders to which physiotherapists are exposed during these two phases. METHOD: Five physiotherapists performed five 20 min manual lymphatic drainages, followed by the compression bandaging phase. From the video recordings, 8477 postures defined by 13 joint angles were grouped into clusters using hierarchical cluster analysis. The risk of musculoskeletal disorders in physiotherapists' postures was assessed using ergonomic tools. RESULTS: Seven clusters, called generic postures (GP), were identified and defined throughout the mean joint angle values and standard deviation. Four seated GPs were found for the drainage phase, and three standing GPs were identified for the bandaging phase. This phase corresponded to a quarter of the total duration. The GP's ergonomic scores ranged from 4.51 to 5.63 and from 5.08 to 7.12, respectively, for the Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA). GP1, GP3, and GP4 presented the highest ergonomic scores (RULA scores: 5.27 to 5.63; REBA scores: 6.25 to 7.12). The most affected areas were the neck (flexion > 20° for all GPs), trunk (flexion between 25 and 30° for GP2, and GP7 during the bandaging phase and GP4 during the drainage phase), and shoulder (flexion and abduction >20° for all GPs except GP5). CONCLUSIONS: These results highlighted that the two complete decongestive therapy phases could be described as a combination of GP. Ergonomic assessment showed that compression bandaging as well as drainage phases expose physiotherapists to moderate musculoskeletal disorder risks that require "further investigation and change soon".

Workstation Risk Factors for Work-related Musculoskeletal Disorders Among IT Professionals in Indonesia.

Objectives: This study aimed to identify workstation factors influencing work-related musculoskeletal disorders (WMSDs) among information technology (IT) professionals in Indonesia. Methods: A cross-sectional study was conducted among 150 IT workers at small-enterprise companies who were randomly selected across East Java, Indonesia. The data were modeled using multiple linear regression, with a 95% level of confidence for determining statistical significance. Results: The respondents reported that the neck had the highest level of discomfort and was the most at risk of WMSDs, followed by the lower back, right shoulder, and upper back. Screen use duration (p=0.040) was associated with whole-body WMSDs, along with seat width (p=0.059), armrest (p=0.027), monitor (p=0.046), and a combined telephone and monitor score (p=0.028). Meanwhile, the factors significantly related to the risk of WMSDs in the hands and wrist were working period (p=0.039), night shift (p=0.024), backrest (p=0.008), and mouse score (p=0.032). Conclusions: Occupational safety authorities, standards-setting departments, and policymakers should prioritize addressing the risk factors for WMSDs among IT professionals.

A Case Study of Ergonomic Risk Assessment in Slovakia with Respect to EU Standard.

Attention on work-related musculoskeletal disorders (WMSDs) involves statistical surveys showing an increasing trend in the incidence of WMSDs. Technological development has led to new tools and methods for the assessment of physical load at work. These methods are mostly based on the direct sensing of appropriate parameters, which allows more precise quantification. The aim of this paper is to compare several commonly used methods in Slovakia for the assessment of ergonomic risk reflecting current EU and Slovak legislative regulations. A Captiv wireless sensory system was used at a car headlight quality control assembly workplace for sensing, data acquisition and data processing. During the evaluation of postures and movements at work, we discovered differences in the applicable standards: Decree 542/2007 Coll. (Slovak Legislation), the STN EN 1005-4+A1, and the French standards default in the Captiv system. Standards define the thresholds for hazardous postures with significant differences in several evaluated body segments, which affects the final evaluation of the measurements. Our experience from applying improved risk assessment methodology may have an impact on Slovak industrial workplaces. It was confirmed that there is a need to create uniform standards for the ergonomic risk assessment of body posture, including a detailed description of the threshold values for individual body segments.

Dimensional assessment of self-reported musculoskeletal symptoms by workers: A multi-case study.

BACKGROUND: Work-related musculoskeletal disorders (WMSD) encompass a range of conditions affecting muscles, tendons, and nerves. Visual diagrams are widely used to identify symptoms and to generate musculoskeletal discomfort metrics. However, there is no consensus on the number of discomfort dimensions that can originate from self-reported musculoskeletal symptoms by individuals. OBJECTIVE: This study aimed to test the fit of WMSD symptom models from workers in two samples of different sizes. METHODS: A combination of Full-Information Item Factor Analysis (FIFA) and Item Response Theory (IRT) was utilized to analyze and test the models. The study was conducted in two samples of workers (n1 = 6944 and n2 = 420) who had their symptoms identified with the aid of a human body diagram. An analysis was conducted considering each sample's unidimensional and three multidimensional models. RESULTS: The unidimensional model (general musculoskeletal discomfort), bi-dimensional model (discomfort in upper and lower body), and tridimensional model (discomfort in the upper limbs, lower limbs, and trunk) showed good values of factor loading and communalities, along with satisfactory item discrimination ability. Regardless of sample size, parameter estimation for IRT and FIFA proceeded without issues, presenting suitable fit parameters. CONCLUSION: Three models were valid and reliable for more extensive and smaller samples. However, the tridimensional model was best for generating discomfort scores in body regions. Companies and safety professionals can use these findings to devise strategies to mitigate musculoskeletal pains based on perceived symptom locations.

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.

A systematic review of research on sitting and working furniture ergonomic from 2012 to 2022: Analysis of assessment approaches.

This study analyses which aspects of sitting and working furniture ergonomics that may be influenced and how they are assessed. To gather information on the types and assessment techniques connected with influencing furniture ergonomics, a systematic review of the literature was conducted. The papers in the systematic review were published between 2012 and 2022. The articles applied the Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines to limit the 41 papers that were eventually included (N = 41) to those containing keywords like ergonomics, human factors, comfort, working furniture, Chair, assessment and evaluation. The research objective of this systematic review is to provide a comprehensive overview of sitting and working furniture and the main findings, obtaining common assessment techniques for this type of furniture and their suitability. According to the relevant studies, the publications were categorized by summarizing factors like region, gender, research methods, ergonomic assessment techniques and methods used, correlation between assessment techniques and methods, etc. Summaries of the data extracted from the included papers are provided and the applicability of some approaches are assessed. Only a small number of authors have evaluated the ergonomics of furniture used in homes. One of the research gaps is the paucity of research on gender segregation, secular trends, and cultural contexts. These studies heavily rely on quantitative research techniques, and the articles may lack credibility due to the homogeneity of the evaluation techniques. Finally, the authors offer some suggestions for the appropriate ergonomic analysis of furniture.

Three-month work-related musculoskeletal disorders assessment during manual lymphatic drainage in physiotherapists using Generic Postures notion.

OBJECTIVES: The aim of this work was to quantify the postures and to assess the musculoskeletal disorders (MSDs) risk in physiotherapists repeating a manual lymphatic drainage (MLD) over a three-month period. The underlying hypothesis was that there would be Generic Postures (GP) that would be repeated and could be used to more simply describe repetitive and long-duration complex activities. METHODS: The posture of five physiotherapists performing five 20-min MLD at their workplace was captured by two cameras. From the recordings, the adopted postures were extracted every 5 s and quantified through 13 joint angles, that is, 6594 analyzed postures. Rapid Upper Limb (RULA) and Rapid Entire Body Assessment (REBA) were used to assess MSDs risks. A hierarchical analysis was used to define GP. RESULTS: Seven GP were identified through mean values and standard deviation. GP ergonomic assessment showed a low to moderate MSD risk (RULA between 3 and 6 and REBA between 2 and 7). High neck (>20°) and trunk (>15°) flexion were observed for all GP. High shoulder abduction and flexion (>40°) were evidenced for GP3 to GP5. GP1 was the most used (34%) and presented the lowest ergonomic scores (RULA: 4.46 ± 0.84; REBA: 5.06 ± 1.75). GP3 to GP6 had frequency of between 10 and 20%. GP5, GP6, and GP7 obtained the highest ergonomic scores (RULA>5; REBA>7). All physiotherapists use different GP combinations to perform MLD. CONCLUSION: MLD could be described as a combination of GP. Ergonomic analysis showed that MLD exposes physiotherapists to low at moderate MSD risks.

A comparison of muscle activity, posture and body discomfort during the use of different computer screen sizes.

This study aims to compare changes in neck angles, muscle activities, ergonomic risk and body discomfort caused by use of two different computer screen sizes. The 36 female users who participated used displays with 46.99 and 58.42-cm screen sizes and were assessed for craniocervical angle (CCA), craniovertebral angle (CVA), upper trapezius (UT) and sternocleidomastoid (SCM) muscle activity, ergonomic risk and body discomfort for a duration of 1 h. The results showed there were no significant differences when comparing usage between both computer screen sizes (p > 0.05). However, there were significant differences in the CCA, UT muscle activity and body discomfort when comparing before and after usage for both computer screen sizes (p < 0.05). The results indicate that computer users can select different screen sizes for working but should be concerned with neck angle, muscle activity and body discomfort when using for long periods of time.

Ergonomic Design and Assessment of an Improved Handle for a Laparoscopic Dissector Based on 3D Anthropometry.

Laparoscopic surgery (LS) has been shown to provide great benefits to patients compared with open surgery. However, surgeons experience discomfort, low-efficiency, and even musculoskeletal disorders (MSDs) because of the poor ergonomic design of laparoscopic instruments. A methodology for the ergonomic design of laparoscopic dissector handles considering three-dimensional (3D) hand anthropometry and dynamic hand positions was addressed in this research. Two types of hand positions for grasping and stretching were scanned from 21 volunteers using a high-resolution 3D scanner. The 3D anthropometric data were extracted from these 3D hand pose models and used to design an improved handle (IH) that provides additional support for the thumb, a better fit to the purlicue, and a more flexible grasp for the index finger. Thirty subjects were invited to evaluate the IH in terms of muscular effort, goniometric study of motion, and efficiency and effectiveness during four trials of a laparoscopic training task. Questionnaires provided subjective parameters for ergonomic assessment. Positive results included less muscle load in the trapezius as well as significant but small angular differences in the upper limb. No significant reduction in the trial time and no increased percentage of the achievement were observed between the IH and the commercial handle (CH). Improved intuitiveness, comfort, precision, stability, and overall satisfaction were reported. IH provides significant ergonomic advantages in laparoscopic training tasks, demonstrating that the proposed methodology based on 3D anthropometry is a powerful tool for the handle design of laparoscopic dissectors and other surgical instruments.

Postural prevalence, time of day and spent time activities during smartphone weekday use among students: A survey to prevent musculoskeletal disorders.

The long time spent on smartphones in awkward postures exposes young users to the risk of developing musculoskeletal disorders (MSDs). This study aimed to investigate 1) how the duration of smartphone use varies by the time of day and activities and 2) the risks of MSDs based on an analysis of the postures used when interacting with smartphones. A cross-sectional survey was conducted among 263 university students. The duration of smartphone use during a typical weekday was investigated over four times of the day and seven activities. After checking for normality, a nonparametric Friedman test was used to study the differences in the time spent using a smartphone according to the time of day and activity. Postural prevalence during weekdays was analyzed using a taxonomy called SmarTaxo, consisting of 41 postures. The Rapid Upper Limb Assessment (RULA) ergonomic score was chosen to assess the MSD risks associated with each posture. Smartphone use was the highest in the evening (301.1 min; 95 % confidence interval [CI]: 277.4-324.8 min, p < 0.05). Texting (170.8 min; 95 % CI: 152.0-189.6 min) and watching videos (163.6 min; 95 % CI: 146.3-180.9 min) were the most common activities. Three sitting and two walking postures were primarily used in the morning (29.3-36.9 %), afternoon (27.0-44.4 %), and evening (28.9%-38.9 %). Standing postures were preferred in the morning and afternoon (36.9 % and 42.2 %, respectively), while one lying posture was widely reported in the evening (39.2 %). The RULA scores for these postures ranged from 3 to 4. However, four lying postures, often observed during the evening (frequency between 20.5 % and 37.6 % of the time), had RULA scores of 6. In conclusion, the study identified an existing MSD risk among smartphone users, especially with long durations of daily use. Special emphasis should be placed on addressing the reclining postures adopted during evening smartphone use, as they subject students to a significantly elevated risk of MSDs.

Development of an ergonomics management model in the workplace: Introduction of the TUGA ergonomics management and analysis model (TEMA).

BACKGROUND: Conducting practical studies in ergonomics requires attention to all aspects of ergonomics with a comprehensive approach and focus on continuous improvement cycles. OBJECTIVE: This study aimed to develop and present an ergonomics management model in the workplace. METHODS: This study was performed using a three-stage Delphi study with 30 experts and a fuzzy analytical hierarchy process. According to the literature review and experts' opinions, the general cycle of the ergonomics management system with eight steps was developed. New methods were formed in two of these eight steps: the 3rd step (developing an ergonomic evaluation method) and the 5th step (creating a cost-benefit evaluation method). RESULTS: The eight implementation steps of the TEMA were determined as follows: 1) Performing task analysis (TTA), 2) Ergonomic hazard identification, 3) Estimating the ergonomic index, 4) Determining control measures, 5) Evaluating cost-benefit parameter, 6) Implementing control measures, 7) Continuous monitoring, and 8) Evaluating the effectiveness of control measures. The Delphi study revealed that the number of deleted parameters includes one item (burnout), and the remaining parameters were 16 items. The mean CVI and CVR values were 0.92 and 0.80, respectively. Cronbach's alpha values for each of the physical, environmental, and cognitive components and the entire model were 0.91, 0.87, 0.85, and 0.89, respectively. CONCLUSION: Using the mentioned management model can be a practical step towards properly evaluating the most critical dimensions of ergonomics in the workplace and optimal planning to implement control measures to establish a dynamic management system to reduce ergonomic risk factors in the workplace.