The Design and Evaluation of Passive Shoulder Exoskeleton in Reducing Physical Demands

This paper introduces the parallel machine scheduling problems with work related musculoskeletal disorder (WMSD) risk considerations. By the WMSD consideration, we mean that job processing times are an increasing function of occupational repetitive technical actions (OCRA) risk factor. The OCRA index was recruited for risk assessment of occupational repetitive technical actions. WMSD risks were modeled with cumulative mean value of OCRA index. Due to NP-Hard structure of parallel machine scheduling problems with WMSD considerations and learning rate, the solution cannot be found always. However, problem can be solved by transforming assignment problem. In spite of the fact that the computational effort remains O (n 4 ), problem is solved within more efficient time. In this study, a model that includes learning effect and WMSD risk was proposed. WMSD risk was considered as cumulative mean of risk value throughout shift. In order to the balance between productivity and WMSD risk, jobs’ foreseeable cycle time (FCT) value was changed. It is aimed to decrease mean of risk along schedule without increasing total basic process time. The value of sacrifice from the FCT was compensating from job which have optimal, acceptable, borderline or slight risk level. Process time and risk values were recalculated by using new FCT value. Thus, balanced process times and risk values obtained. Proposed model was solved with Lingo software and sequence of jobs was obtained. Total flow time and mean of risk were compared for balanced and none balanced schedules. Total flow time and mean of risk belong to balanced schedule is smaller than none balanced schedule. It was shown that handled problem is solvable at the polynomial time and total flow time can be improved by bringing balance between WMSD risks and productivity.

In this paper, the effects of Occupational Repetitive Actions (OCRA) parameters, learning rate on process times, and machine scheduling were investigated. We propose that Work-Related Musculoskeletal Disorder (WMSD) risks should be taken into account in machine scheduling. To the best of our knowledge, none of the earlier methods simultaneously considered effects of WMSD risks and the learning rate on processing times. The OCRA index method was employed for WMSD risk assessments. In this context, OCRA parameters such as duration, recovery, force, posture, and repetitiveness were analyzed. Observed process times of each factor were obtained from video records. Statistical analysis (ANOVA) revealed a positive (r=0.616) relationship on processing times with OCRA indexes in independent t-tests at significance level 0.05. To investigate the effects of WMSD risk, our Scheduling with Learning Effect under Risk Deterioration (SLE&RD) model was compared with six existing machine scheduling models in the literature. Detailed machine scheduling instances of 9 jobs with WMSD risks revealed that job sequences and makespan varied under different scenarios. This means that WMSD risks and OCRA factors affect machine scheduling with a deterioration effect. The results confirmed that when WMSD risks are included, actual process time and makespan move closer to observed process times. To obtain more accurate machine scheduling, which is close to real-life applications, WMSD risks, and learning rates should be considered simultaneously. The SLE&RD model is promising in machine scheduling for real-life problems and presents a holistic view of machine scheduling and WMSD risks.

Risk Assessment and Prevalence of Work-Related Musculoskeletal Disorders Among Cranial and Spinal Neurosurgeons

This study addresses the relationship between human factors (HF) related quality deficits in manufacturing and work-related musculoskeletal disorder (WMSD) risk factors in production staff. A recent systematic review identified 60 HF-related quality risk factors (QRFs) in manufacturing related to product, process and workstation design stages. We investigate the extent to which these identified QRFs are also WMSD risk factors. Each QRF was examined for its relationship with WMSD using a 0 (no relationship) to 10 (strong relationship) scale rubric. The authors rated each QRF separately and then discussed and adjusted their ratings in a review session. Results showed that average median ratings were the highest for QRFs related to product design (8/10), intermediate for QRFs related to workstation design (7/10) and the lowest for QRFs related to process design (5/10). This emphasises the significant role of HF in system design in reducing both quality deficits and risk of developing WMSDs for manufacturing personnel. Practitioner summary: This study investigates whether human-related risk factors for product quality are also risk factors for work-related musculoskeletal disorders in manufacturing. Results showed a substantial relationship between quality risk factors and WMSD risk factors. This indicates the significant role of human factors in operations design in improving both system performance and human wellbeing.

This study investigated whether work dedication and job resources are longitudinally related to work-related musculoskeletal disorders and whether job resources buffer the impact of job demands on these disorders? Data were used from a longitudinal three-phase study (2004, 2005, 2006) on health at work among a sample of Dutch workers. The first survey was sent in 2004 by e-mail to 3100 members of an existing panel. For the analyses, 1522 participants were included with full longitudinal data. The analyses were performed using an autoregressive model with generalized estimating equations. The job-resource quality of communication was found to predict the risk of work-related musculoskeletal disorders over time. This effect was not mediated by work dedication. A high quality of communication was also found to buffer the negative effects of a high physical workload on the risk of work-related musculoskeletal disorders. Furthermore, a low level of social support by colleagues was found to buffer the negative effect of a medium physical workload on work-related musculoskeletal disorders. This study shows that job resources are not only important for promoting work dedication, but may also moderate the negative impact of high job demands on the risk of work-related musculoskeletal disorders. With respect to social support, the question is raised of whether this can also work negatively. The results of this study imply that, besides avoiding or reducing risks to health in the workplace and lowering job demands, strengthening job resources may additionally buffer harmful effects of job demands on musculoskeletal health.

Work Sectors with High Risk for Work-Related Musculoskeletal Disorders in Korean Men and Women

Exoskeleton (EXO) technologies are a promising ergonomic intervention to reduce the risk of work-related musculoskeletal disorders, with efficacy supported by laboratory- and field-based studies. However, there is a lack of field-based evidence on long-term effects of EXO use on physical demands. A longitudinal, controlled research design was used to examine the effects of arm-support exoskeleton (ASE) use on perceived physical demands during overhead work at nine automotive manufacturing facilities. Data were collected at five milestones (baseline and at 1, 6, 12, and 18 months) using questionnaires. Linear mixed models were used to understand the effects of ASE use on perceived work intensity and musculoskeletal discomfort (MSD). Analyses were based on a total of 41 participants in the EXO group and 83 in a control group. Across facilities, perceived work intensity and MSD scores did not differ significantly between the EXO and control groups. In some facilities, however, neck and shoulder MSD scores in the EXO group decreased over time. Wrist MSD scores in the EXO group in some facilities remained unchanged, while those scores increased in the control group over time. Upper arm and low back MSD scores were comparable between the experimental groups. Longitudinal effects of ASE use on perceived physical demands were not found, though some suggestive results were evident. This lack of consistent findings is discussed, particularly supporting the need for systematic and evidence-based ASE implementation approaches in the field that can guide the optimal selection of a job for ASE use.

Occupational ApplicationsOccupational Applications Healthcare workers who use syringes and use their hands frequently have increased risk for work-related musculoskeletal disorders. Syringe use, handling, writing, and other pinch grip tasks occur in chemotherapy, pharmaceuticals, laboratories, and dietetics. Many hospitals have similar tasks where medications are administered to patients via syringes or IV bags. With limited research available, this study sought to gain further insight by exploring hand and syringe tasks in the healthcare field. Evidence of muscular overload for nurses and pharmacy assistants performing syringe (intravenous push treatments) and hand tasks was indicated by a high number of hand efforts combined with prolonged durations, thumb forces, and high muscle activity with a lack of muscular rest. Pharmacy assistants also presented a higher risk for work-related musculoskeletal disorders. The results of this study can assist workers in the chemotherapy department, and may impact professions with similar hand and syringe efforts, by creating an awareness of the tasks performed, the extent of hand use, and associated work-related musculoskeletal disorders risk while providing risk reduction strategies.Technical Rationale: There is a need to evaluate and redesign manual “pushing” and mixing chemotherapy drugs to prevent musculoskeletal disorders to hospital staff, improve patient care quality, and reduce healthcare costs. Purpose: The purpose of this study was to examine hand and syringe actions required of workers in chemotherapy preparation and administration over a work shift, and to propose risk control strategies. Methods: Thumb forces and muscle activity from the forearm flexor and extensor muscles were measured from five lab nurses, five floor nurses and five pharmacy assistants; each had their actions recorded throughout their shift. Results: Pharmacy assistants and nurses spent the majority of the work shift performing hand tasks (87% and 72%, respectively). Lab nurses performed a mean (SD) of 1.85 (0.48) hand efforts per min, floor nurses performed 1.62 (0.09) per min, while pharmacy assistants performed significantly more at 5.29 (1.27) per min. Syringe use accounted for 17% of the pharmacy assistants’ shift and 12% for floor and lab nurses. Drawing fluid and manually pushing treatment represented 10% of the work day. Thumb forces reached up to 57% of maximum, and muscle activity reached 58% of maximum for the twist task (connecting syringe-IV tubing). The left forearm flexors exhibited the highest activity over the workday and across tasks while only resting for 6% of the workday. Conclusions: The high number of hand efforts, combined with prolonged durations, muscle activity, thumb force, and lack of muscular rest, provide evidence of muscular overload over the course of the shift suggesting that pharmacy assistants have higher risk for work-related musculoskeletal disorders. These results may also help explain injury statistics and complaints associated with the arm, hand, and thumb in chemotherapy departments. Findings and suggested risk reduction strategies can act as a guide for future evaluation of workplaces with similar syringe and hand demands.

Long-term work with elevated arms, or overhead work, is a risk factor for musculoskeletal complaints and disorders. Upper-limb exoskeletons are a promising tool for reducing occupational workload when working with hands above shoulder level. The purpose of this study was to assess the effects of upper-limb exoskeleton on muscular and physical strain and perceived exertion during dynamic work at four different shoulder joint angles. Further, we evaluated if there are any negative effects associated with the use of exoskeleton. A total of 15 student participants performed dynamic work in laboratory setting with and without an exoskeleton at four different shoulder angles: 60, 90, 120 and 150 degrees. Muscle electrical activity from 8 muscles of the upper body, perceived exertion, and heart rate were measured during the work task, and grip strength, muscle stiffness, tone, and elasticity from six muscles, m. deltoideus physiological cross-sectional area and muscle fiber pennation angle, and nerve conduction velocity were measured before and after the work task. Based on the results, the use of exoskeleton significantly reduced the muscle activity of the upper limb, shoulder, and back muscles. The reduction was most significant when the arm elevation was 120°, and in m. deltoideus muscle activity. RPE was also positively affected indicating reduction in workload when using exoskeleton. The results suggest that the use of upper limb exoskeleton has potential to reduce physical workload during overhead work and, consequently, reduce the risk for work-related musculoskeletal disorders.

Lifting and loading passengers’ hand-carry luggage into the overhead compartment in the flight cabin is one of the tasks performed by the cabin crews. The hand-carry luggage weight varies and can be up to 10 kg. The task involved load lifting over the head, awkward posture and repetitive that could lead to the risk of work-related musculoskeletal disorders (WMSDs). Hence, further investigation of those factors stimulates this study. An industrial survey was conducted and WMSDs symptom data were collected using Nordic Musculoskeletal Questionnaire (NMQ). Rapid Upper Limb (RULA) assessment was performed to analyse the posture during the load lifting task. The results of the industrial survey indicated that 88.3% of the workers experienced WMSD symptoms in various regions of the body. The highest symptoms reported at lower back (80.0%), followed by the neck (68.0%) and shoulder (59.0%). The result is supported with the result of RULA with final score 7, which indicated the load lifting task performed involved awkward posture, needs changes and further improvement should be immediately implemented. In conclusion, the cabin crews exposed to the risks of WMSDs and the results of this study can be used as references by the aviation industry to mitigate WMSDs issues among the cabin crews specifically and contribute to the improvement of the society well-being generally.

Exposure to adverse ergonomic factors is associated with elevated risk of work-related musculoskeletal disorders (WMSDs) in medical personnel. We aimed to reveal how different adverse ergonomic factors act individually and in combination to influence the risk of WMSDs in medical personnel. From June 2018 to December 2020, we applied multistage cluster random sampling to select a total of 6,099 medical personnel from 54 hospitals in 12 cities in China. All participants were aged over 18 years and had at least one year of hospital working experience. The weighted quantile sum (WQS) model was employed to evaluate the effect of mixed exposures of multiple adverse ergonomic factors on the risk of WMSDs. Compared to a single factor, multiple adverse ergonomic factors significantly increased the risk of WMSDs across body parts, with an OR ranging from 2.83 (95% CI: 2.33, 3.43) to 6.92 (95% CI: 4.91, 9.74). “Working in awkward positions” had the greatest impact on the risk of WMSDs in the neck, shoulder, upper back, and lower back, while “standing for prolonged periods of time” mostly affected the risk of WMSDs in the foot, leg, and knee. Compared with single factor exposure, mixed exposure resulted in a higher risk of WMSDs.

BackgroundMusculoskeletal disorders (MSDs) are one of the most common occupational diseases and the main cause of disability worldwide. Work-related musculoskeletal disorders (WMSDs) are one of the common health risks and the most important cause of absenteeism due to disability in various industries, including the petrochemical industry, in developed and developing countries. These disorders have important social economic, and significant financial consequences due to direct and hidden costs. Health behaviors play a role in both creating and preventing musculoskeletal disorders in employees. Therefore, by identifying the influencing factors on these behaviors, it is possible to strengthen and improve the preventive behaviors of musculoskeletal disorders through educational intervention programs. This study aims to assess the behavioral risk of work-related musculoskeletal disorders, and design and implement an educational intervention to teach effective behaviors in the prevention of musculoskeletal disorders in petrochemical industry workers.MethodsThis study is a mixed-method study implemented in four stages involving the qualitative study, the design and evaluation of an instrument, the design of an experimental randomized clinical trial, and the psychometric evaluation of the instrument and the evaluation of the program. The research community consists of employees working in the petrochemical industry. The volume of samples in the qualitative study with the purposeful sampling method, in the instrument design stage based on the available sampling method, and also in the experimental study, the samples are employees suffering from work-related musculoskeletal disorders, who were selected based on a simple random method from among the employees of the petrochemical industry. Then they will be divided into intervention and control groups. The instruments of this research include a demographic questionnaire, a researcher-made questionnaire for measuring behavior, and two auxiliary instruments including the visual analog scale (VAS) and the Quebec Disability Scale. Evaluation is done in 4 stages: pre-test, immediately, 3, and 6 months after the intervention of both groups. The obtained data will be analyzed using SPSS software.DiscussionMusculoskeletal disorders related (WMSDs) to work can harm employees’ health in various industries, including the petrochemical industry. This study attempts to evaluate the behavioral risk of work-related musculoskeletal disorders among petrochemical industry workers and design and implement an appropriate educational intervention program.Trial registrationIranian Registry of Clinical Trial (IRCT20240321061346N1). Registered on 2024–04-10.Ethics Status: Ethics code: IR.MODARES.REC.1402.251.

A two-dimensional posture measurement system was developed to evaluate the risks of work-related musculoskeletal disorders(MSDs) easily on various conditions of work. The posture measurement system is an essential tool to analyze the workload for preventing work-related musculoskeletal disorders. Although several posture measurement systems have been developed for workload assessment, some restrictions in industry still exist because of its difficulty on measuring work postures. In this study, an image recognition algorithm was developed based on a neural network method to measure work posture. Each joint angle of human body was automatically measured from the recognized images through the algorithm, and the measurement system makes it possible to evaluate the risks of work-related musculoskeletal disorders easily on various working conditions. The validation test on upper body postures was carried out to examine the accuracy of the measured joint angle data from the system, and the results showed good measuring performance for each joint angle. The differences between the joint angles measured directly and the angles measured by posture measurement software were not statistically significant. It is expected that the result help to properly estimate physical workload and can be used as a postural analysis system to evaluate the risk of work-related musculoskeletal disorders in industry.

Musculoskeletal disorders (MSDs) are conditions that are caused and/or aggravated by work. The most important reason behind work-related musculoskeletal disorder is abnormal and/or stressful position of joints while working. Physiotherapists are very much prone to develop work-related musculoskeletal disorders, especially while treating neurologically challenged patients. Postural assessment is a key to identify a person at risk of developing work-related musculoskeletal disorders. Proper assessment of some of the areas like neck, spine, upper and lower extremities is the key to get risk factor analysis. REBA (Rapid Entire Body Assessment) is a tool which can be used on field to quantify areas of the body which are more likely to develop work-related musculoskeletal disorders. To find out risk of MSDs among physiotherapists treating neurologically challenged patients. At neuro-paediatric department of SBB College of Physiotherapy, an observational pilot study was conducted. Photographs of the participants were captured with their consent through smart phone camera during treatment of different patients both adult and paediatric. Selected postures were analysed and quantified based on the REBA sheet. Descriptive analysis was done based on areas at higher risk for MSDs according to REBA sheet. More than 50% of participants were at moderate to high risk of developing MSDs. Physiotherapists working with neurological patients were found to be at high to medium risk of work-related musculoskeletal disorders. There is a need to assess MSD risk in detail in all physiotherapists.

Fusing imperfect experimental data for risk assessment of musculoskeletal disorders in construction using canonical polyadic decomposition