Preventing worker’s musculoskeletal disorders with wearable inertial sensors: ergonomics and modelling of physical human-robot interactions

The most widespread work-related diseases are musculoskeletal disorders (MSD) caused by awkward postures and excessive effort to upper limb muscles during work operations. The use of wearable IMU sensors could monitor the workers constantly to prevent hazardous actions, thus diminishing work injuries. In this thesis, procedures are developed and tested for ergonomic analyses in a working environment, based on a commercial motion capture system (MoCap) made of 17 Inertial Measurement Units (IMUs). An IMU is usually made of a tri-axial gyroscope, a tri-axial accelerometer, and a tri-axial magnetometer that, through sensor fusion algorithms, estimates its attitude. Effective strategies for preventing MSD rely on various aspects: firstly, the accuracy of the IMU, depending on the chosen sensor and its calibration; secondly, the correct identification of the pose of each sensor on the worker’s body; thirdly, the chosen multibody model, which must consider both the accuracy and the computational burden, to provide results in real-time; finally, the model scaling law, which defines the possibility of a fast and accurate personalization of the multibody model geometry. Moreover, the MSD can be diminished using collaborative robots (cobots) as assisted devices for complex or heavy operations to relieve the worker's effort during repetitive tasks. All these aspects are considered to test and show the efficiency and usability of inertial MoCap systems for assessing ergonomics evaluation in real-time and implementing safety control strategies in collaborative robotics. Validation is performed with several experimental tests, both to test the proposed procedures and to compare the results of real-time multibody models developed in this thesis with the results from commercial software. As an additional result, the positive effects of using cobots as assisted devices for reducing human effort in repetitive industrial tasks are also shown, to demonstrate the potential of wearable electronics in on-field ergonomics analyses for industrial applications.

Musculoskeletal disorders, research quality, and pelvic floor health in sports: exploring current evidence and new perspectives

Background. Pelvic floor dysfunction (PFD) is an umbrella term that includes a myriad of conditions such as urinary (UI) and anal incontinence, pelvic organ prolapse, pelvic pain, and sexual dysfunction. Literature showed high prevalence rates of PFD among athletes, especially UI, with high-impact sports have been linked with an increased risk of developing symptoms. However, comprehensive research summarising PFD prevalence across sexes, exploring treatment options, and the absence of a standardised referral screening tool are notable gaps. Misinformation is also prevalent in the sports medicine field. Methods. This doctoral project comprises four studies addressing different aspects of pelvic health in athletes. The first two studies were scoping reviews of epidemiological PFD data in male and female athletes, as well as available interventions. Study 3 concerned the development of a new screening tool for PFD in female athletes, aiming to guide sports medicine clinicians in referring patients to PFD specialists through a worldwide Delphi consensus. Study 4 summarised all previous findings, integrating data into an infographic. Results and conclusions. In Study 1, the findings of 100 articles on PFD in both sexes have been collected, highlighting a higher prevalence of studies on female athletes evaluating UI across multiple sports. Other conditions remain rarely investigated. Study 2 found a diverse range of interventions for female PFD, with a notable emphasis on conservative approaches. Recommendations for clinical practice often relied on the transferability of results from the nonathlete population or expert opinions. In Study 3, 41 international experts took part in the consensus development of the Pelvic Floor Dysfunction-ScrEeNing Tool IN fEmale athLetes (PFD-SENTINEL). It incorporates a cluster of PFD symptoms, items (risk factors, clinical, and sports-related characteristics), and a clinical algorithm. Lastly, Study 4 included ten evidence-based information with a relative description concerning pelvic floor health in athletes.

Prevalence of work-related musculoskeletal disorders in Brazilian hairdressers

Background There are occupational risks inherent to the activities of professional hairdressers, which are not frequently studied, and therefore not considered in the formulation of health policies for this group. Aims To verify the prevalence of work-related musculoskeletal disorders (WRMDs) in hairdressers through symptom reports, to characterize the most frequently affected anatomical parts and to identify and analyse risk factors of WRMDs in hairdressing. Methods A cross-sectional epidemiological study of 220 hairdressers from beauty parlours in Sao Paulo (Brazil) was carried out. Each hairdresser completed a self-administered questionnaire which included information on socio-demographic characteristics, working conditions and health-related musculoskeletal system complaints. Ergonomic analyses were also performed in six parlours. Results The prevalence of WRMDs was 71%. Risk factors were associated with psychosocial factors and factors related to discomfort and work fatigue such as lack of acknowledgement of work and uncomfortable posture at work [odds ratio (OR) = 3.54; 95% confidence interval (CI) 1.51-8.30], not feeling comfortable with body/neck/shoulders while working (OR = 2.78; 95% CI 1.40-5.54) and having > 15 years of professional activity (OR = 3.04; 95% CI 1.17-7.91). Conclusion Occupational risk factors associated with the development of WRMDs in hairdressers are related to biomechanical, organizational and psychosocial work factors. The high prevalence of WRMDs found highlights the importance of disseminating recommendations for prevention of symptoms with regards to the provision of suitable furniture, equipment and work tools, environmental conditions, size of workplace, work organization and psychosocial work factors.

Clinical and functional aspects of work-related musculoskeletal disorders among active workers

OBJECTIVE: To evaluate musculoskeletal disorders among active industrial workers. METHODS: The study was carried out in São Carlos, Southeastern Brazil, in 2005. One hundred and thirty-four female workers were physically evaluated and answered questions about their physical symptoms, filled out a pain scale and gave responses in the Oswestry Disability Questionnaire, and the Work Ability Index questionnaire. The data were analyzed descriptively, and in correlation tests and through applying logistic regression. The outcome was evaluated in relation to the perceptions of pain, symptoms, physical assessment, ability to work and disability. RESULTS: Clinical evaluations and sick leave presented positive correlations with the subjective variables. The Work Ability Index presented a negative correlation with the physical disability index (r=-0.69). Symptoms reported at the time of the assessment presented a good correlation with the results from the pain scale and the clinical findings. Previous sick leave showed an association with disability (OR=1.13; 95% CI:1.08;1.18). CONCLUSION: Symptom reports and pain scales may be useful for assessing current conditions at the time of evaluating individuals with work-related musculoskeletal disorders, as they are easier to apply. In more severe cases of such injuries, clinical and functional evaluations and questionnaires such as those relating to ability to work and disability are preferable. Precise and specific evaluations of these disorders may contribute towards fairer legal and administrative decisions.

A study compared nine patient-specific indices for musculoskeletal disorders.

BACKGROUND AND OBJECTIVE: Patient-specific quality of life indices show great potential, but certain conceptual and methodological concerns have yet to be fully addressed. The present study reviewed nine patient-specific instruments used in musculoskeletal disorders: the Canadian Occupational Performance Measure (COPM), Juvenile Arthritis Quality of life Questionnaire (JAQQ), McMaster-Toronto Arthritis questionnaire (MACTAR), Measure Yourself Medical Outcome Profile (MYMOP), Patient-Specific Index (PASI) for total hip arthroplasty, Problem Elicitation Technique (PET), Patient Generated Index (PGI) of quality of life, Patient-Specific Functional Scale (PSFS), and Schedule for the Evaluation of Individual Quality of Life (SEIQoL). STUDY DESIGN AND SETTING: Each tool was evaluated for purpose, content validity, face validity, feasibility, psychometric properties, and responsiveness. RESULTS: This critical appraisal revealed important differences in terms of the concept underlying these indices, the domains covered, the item-generation techniques and the scoring (response scale, methods) in each scale. The nine indices would generate different responses and likely scores for the same patient, despite the fact that they all include patient-generated items. CONCLUSION: Although the value of these indices in treatment planning and monitoring at an individual level is strong, more studies are needed to improve our understanding of how to interpret the numeric scores of patient-specific indices at both an individual and a group level.

Modeling Of Work-Related Musculoskeletal Disorders In Chemical Process Industry In India

In this modern complex world, stress at work is found to be increasingly a common feature in day to day life. For the same reason, job stress is one of the active areas in occupational health and safety research for over last four decades and is continuing to attract researchers in academia and industry. Job stress in process industries is of concern due to its influence on process safety, and worker‘s safety and health. Safety in process (chemical and nuclear material) industry is of paramount importance, especially in a thickly populated country like India. Stress at job is the main vector in inducing work related musculoskeletal disorders which in turn can affect the worker health and safety in process industries. In view of the above, the process industries should try to minimize the job stress in workers to ensure a safe and healthy working climate for the industry and the worker. This research is mainly aimed at assessing the influence of job stress in inducing work related musculoskeletal disorders in chemical process industries in India

Prevalencia de desordenes musculo-esqueléticos y factores asociados en trabajadores de una caja de compensación familiar en el año 2012

Objetivo: determinar la prevalencia de síntomas osteomusculares generales y los factores asociados en los trabajadores de una Caja de compensación en Bogotá, Colombia, 2012 Métodos: estudio observacional, de corte transversal, en los trabajadores que desarrollan actividades asistenciales y administrativos. Se aplicaron encuestas de síntomas y factores ergonómicos específicos para el individuo basado en el Cuestionario Estandarizado Nórdico para la detección y análisis de los síntomas músculo-esqueléticos asociados con preguntas tomadas de la Encuesta de Condiciones de Trabajo y Salud. Resultados: la población de estudio fue de 232 trabajadores, 68,97% eran mujeres y el 31,3% eran varones. La edad media es de 24,5 años. La mayor prevalencia de trastornos musculoesqueléticos está en la mano y la muñeca derecha con un 12,07% de la población, seguido por el hombro derecho con un valor de 6,9%, seguido por cuello y espalda. Se encontró una p <0,05 para molestias en mano y muñeca derecha en las personas que tienen puestos administrativos, requieren hacer un trabajo rápido y el ritmo de trabajo está determinado por sus jefes. Conclusión: Los trastornos musculoesqueléticos son una situación muy compleja, que está influenciada por factores individuales, psicosociales y ambientales que interactúan incrementando el riesgo de producir ciertas enfermedades. Es necesario llevar a cabo un enfoque multivariado para personas con este tipo de patología.

Dental Practice and Musculoskeletal Disorders Association: A Look at the Evidence

Disorders localized to the musculoskeletal system are a common problem among dental personnel. This study has the aim of surveying epidemiological studies reporting positive associations between dental practice and musculoskeletal disorders (MSKDs). The focus was to evaluate the size of reported risk increase and the extent to what alternative causal explanations were considered. Reports with significant links (p value .05) were systematically selected from 2 electronic databases. Twenty-five studies were identified. Risk measures were reported in 8 studies, and all of them presented weak associations. The impact of at least 1 competing explanations was analyzed in 32% of studies, but adjustment was considered not adequate in half of them. The evidence on dentistry as a profession with potential risk for development of MSKDs remains questionable. Further research is needed to more carefully elucidate the risk and the impact of MSKDs in this particular occupational group.

Musculoskeletal disorders in upper limbs in dental students: exposure level to risk factors

Aim: This study assessed the risk factors of undergraduate students to develop musculoskeletal disorders (MSD) in the upper limbs, regarding gender, type of dental clinical procedure, mouth region treated, and the four-handed dentistry practice. Methods: Dental students enrolled in the 8th semester in the Araraquara School of Dentistry, UNESP, Brazil, were photographed while practicing 283 dental procedures. The Rapid Upper Limb Assessment (RULA) method was used to evaluate the working postures of each student. The photographs were evaluated and a final risk score was attributed to each analyzed procedure. The prevalence of risk factors of developing MSD was estimated by point and by 95% confidence interval. The association between the risk factor of developing disorders and variables of interest were assessed by the chi-square test with a significance level of 5%. Results: The risk factors of developing MSD were high, regarding most dental procedures performed by the undergraduate students (score 5: 7.07%, CI95%: 4.08- 10.06%; score 6: 62.54%, CI95%: 56.90-68.18%). There was no significant association between the RULA final score and gender (p=0.559), and type of dental procedure (p=0.205), and mouth regions by arch (p=0.110) or hemi-arch (p=0.560), and the use of four-handed dentistry (p=0.366). Conclusions: It can be concluded that gender, type of dental clinical procedure, mouth region treated, and practice of four-handed dentistry did not influence the risk of developing MSD in the upper limbs among the dental students evaluated; however, they are at a high risk of developing such disorders.

Physical and psychosocial risk factors for musculoskeletal disorders in Brazilian and Italian nurses

As part of the international CUPID investigation, we compared physical and psychosocial risk factors for musculoskeletal disorders among nurses in Brazil and Italy. Using questionnaires, we collected information on musculoskeletal disorders and potential risk factors from 751 nurses employed in public hospitals. By fitting country-specific multiple logistic regression models, we investigated the association of stressful physical activities and psychosocial characteristics with site-specific and multisite pain, and associated sickness absence. We found no clear relationship between low back pain and occupational lifting, but neck and shoulder pain were more common among nurses who reported prolonged work with the arms in an elevated position. After adjustment for potential confounding variables, pain in the low back, neck and shoulder, multisite pain, and sickness absence were all associated with somatizing tendency in both countries. Our findings support a role of somatizing tendency in predisposition to musculoskeletal disorders, acting as an important mediator of the individual response to triggering exposures, such as work-load.

The risk of musculoskeletal disorders for workers due to repetitive movements during tomato harvesting

Tomatoes are the most common crop in Italy. The production cycle requires operations in the field and factory that can cause musculoskeletal disorders due to the repetitive movements of the upper limbs of the workers employed in the sorting phase. This research aims to evaluate these risks using the OCRA (occupational repetitive actions) index method This method is based firstly on the calculation of a maximum number of recommended actions, related to the way the operation is performed, and secondly on a comparison of the number of actions effectively carried out by the upper limb with the recommended calculated value. The results of the risk evaluation for workers who manually sort tomatoes during harvest showed a risk for the workers, with an exposure index greater than 20; the OCRA index defines an index higher than 3.5 as unacceptable. The present trend of replacing manual sorting onboard a vehicle with optical sorters seems to be appropriate to reduce the risk of work-related musculoskeletal disorders (WMSDs) and is supported from both a financial point of view and as a quality control measure.

Psychosocial factors and musculoskeletal symptoms in a vulnerable working population in Nicaragua

This research is a secondary data analysis of the CUPID-INCA Nicaragua study, a cross-sectional study comparing psychosocial and physical factors on musculoskeletal symptoms among nurses, office workers and maquiladoras in Nicaragua. There were three objectives for this thesis. (1) To describe the study population according to their socio-demographic, psychosocial (i.e. work organization and health beliefs) and physical factors. (2) To estimate the prevalence of musculoskeletal disorders (MSDs) in the study population (nurses, office workers and maquilas). (3) To analyze and compare the trends of association between psychosocial factors and MSDs to that of physical factors and MSDs in the study population. Trends of association between MSDs and psychosocial factors were also compared between nurses, office workers and maquilas. ^ Majority of the total study population were females, middle aged, non smokers and had been on the job for more than five years. Prevalence rates of low back pain and upper extremity pain were 28% and 37% respectively in nurses, 17% and 34% in office workers and 18% and 31% in maquilas. Workers' health belief was significantly associated with MSDs in all three occupational groups. Psychosocial factors were not consistently associated more with MSDs than physical factors. Maquilas had more psychosocial factors statistically significantly associated with musculoskeletal symptoms than nurses and office workers. ^ The findings of this research suggest that both psychosocial and physical risk factors play a role on the prevalence of musculoskeletal symptoms in the three working populations in Nicaragua. Future research in this area should explore further, the risk of developing MSDs from workers' exposure to psychosocial factors as well as physical factors.^

Labor force activity among Australians with musculoskeletal disorders comorbid with depression and anxiety disorders

Aim: Musculoskeletal disorders (MSD) are a leading cause of work-related disability. This investigation explored the impact of MSD comorbid with depression and anxiety disorders, on labor force activity. Methods: The Australian Bureau of Statistics provided confidentialized data files collected from a household sample of 37,580 people. MSD, affective, and anxiety disorders were identified and employment restrictions were assessed at four levels of severity. Results: Anxiety and depression of six months duration was present in 12.1% of people with MSD. Comorbidity magnified the negative impacts of single conditions on labor force activity. Most at risk were people with back problems and comorbid depression, people with arthritis or other MSD and comorbid anxiety, males with MSD and comorbid depression, and females with MSD and comorbid anxiety. Conclusions: The results suggest that the occupational rehabilitation needs of people with MSD comorbid with depression or anxiety may currently be underestimated.

Objective Methods for Characterizing Physical Exposures which may contribute to Work-related Musculoskeletal Disorders in Agricultural Workers

Thesis (Ph.D.)--University of Washington, 2016-08