BACKGROUND AND SIGNIFICANCE. Various studies have identified physical risk factors for musculoskeletal disorders (MSDs) associated with hand harvesting of crops, due to repetitive motions, lifting or carrying of heavy loads, and working in flexed trunk postures. A paucity of research exists on ergonomic risks to tomato farmworkers. The available studies have estimated risk based on self-reports of injury and semi-quantitative measures. METHODS. A partnership between East Tennessee State University (ETSU) and a migrant health center (Rural Medical Services) has identified some of the occupational health needs of this population. With the aid of surface electromyography (sEMG), an objective-quantitative tool, a more refined understanding of ergonomic health risks for this population will be developed. The purpose of this study is to evaluate the muscle load and fatigue induced on the anterior deltoid and upper trapezius muscles during three tasks: driving stakes into the ground, tying of tomatoes to stakes, and hoisting of a 35-pound bucket full of tomatoes. Space for a mock test plot, where the study will be conducted, is available at the ETSU’s Valleybrook facility. Muscle activity recordings will be obtained from 15 tomato farmworkers. Spectral analysis and the amplitude probability distribution function (APDF) will be used to assess fatigue and muscle load respectively. A repeated measures ANOVA will be employed in the study. ANTICIPATED RESULTS. Findings of this study should show that localized muscle loading increases muscle fatigue. Neuromuscular demand should vary, depending on the type of task performed. Stake pounding may show a higher neuromuscular demand than the other tasks. AIM 1. Evaluate the magnitude of muscle activity during three simulated tomato-field tasks and measure the intensity of movement during the stake pounding task. AIM 2. Compare estimates of muscle fatigue and muscle load induced on the anterior deltoid and upper trapezius muscles during three simulated tomato-field tasks.

Prolonged computer work is associated with high rates of neck and shoulder pain symptoms, and as computers have become increasingly more common, it is becoming critical that we develop sustainable interventions targeting this issue. Static muscle contractions for prolonged periods often occur in the neck/shoulder during computer work and may underlie muscle pain development in spite of rather low relative muscle load levels. Causal mechanisms may include a stereotypical recruitment of low threshold motor units (activating type I muscle fibers), characterized by a lack of temporal as well as spatial variation in motor unit recruitment. Based on this theory, although studies have postulated that individuals with chronic neck-shoulder pain will show less variation in muscle activity compared to healthy individuals when engaged in repetitive/monotonous work, this has seldom been verified in empirical studies of actual computer work. Studies have rarely addressed temporal patterns in muscle activation, even though there is a consensus that temporal activation patterns are important for understanding fatigue and maybe even risks of subsequent musculoskeletal disorders. This study applied exposure variation analysis (EVA) to study differences in temporal patterns of trapezius muscle activity as individuals with and without pain performed computer work. The aims of this study were to: Assess the reliability of EVA to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work; Determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA. Thirteen touch-typing, right-handed participants were recruited in this study (8 healthy; 5 chronic pain). The participants were asked to complete three 10-minute computer tasks (TYPE, CLICK and FORM) in two pacing conditions (self-paced, control-paced), with the healthy group completing two sessions and the pain group completing one. Activation of the upper trapezius muscle was measured using surface electromyography (EMG). EMG data were organized into 5x5 EVA matrices with five amplitude classes (0-6.67, 6.67-20, 20-46.67, 46.67-100, >100% Reference Voluntary Exertion) and five duration classes (0- 1, 1-3, 3-7, 7-15, >15 seconds). EVA marginal distributions (along both amplitude and duration classes) for each EVA class, as well as summary measures (mean and SD) of the marginal sums along each axis were computed. Finally, “resultant” mean and SD across all EVA cells were computed. The reliability in EVA indices was estimated using intra-class correlation coefficients (ICC), coefficient of variation (CV) and standard error of measurement (SEM), computed from repeated measurements of healthy individuals (aim 1), and EVA indices were compared between groups (aim 2). Reliability of EVA amplitude marginal sums ranged from moderate to high in the self-paced condition and low to moderate in the control-paced condition. The duration marginal sums were moderate in the self-paced condition and moderate to high in the control-paced condition. The summary measures (means and SDs) were moderate to high in both the self-paced and control-paced condition. Group comparisons revealed that individuals with chronic pain spent longer durations of work time in higher EVA duration categories, exhibited larger means along the amplitude, duration and in the resultant, and higher EVA SD in the amplitude and duration axes as compared to the healthy group. To our knowledge, this is the first study to report on the reliability of EVA applied specifically to computer work. Furthermore, EVA was used to assess differences in muscle activation patterns as individuals with and without chronic pain engaged in computer work. Individuals in the pain group seemed to exhibit prolonged sustained activation of the trapezius muscle to a significantly greater extent than controls, even though they did not experience pain during the performance of the computer tasks (as obtained through self-reports). Thus, these altered muscle recruitment patterns observed in the pain subjects, even in the absence of task-based pain/discomfort, are suggestive of chronic motor control changes occurring in adaptation to pain, and may have implications for the etiology of neck and upper-limb musculoskeletal disorders. / Master of Science / This study aims to assess the reliability of exposure variation analysis (EVA) to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work, and to determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA. Muscle activation was recorded for eight healthy individual and five suffering from chronic neck-shoulder pain. The data were then categorized into amplitude and continuous time categories, and summary measures of resulting distributions were calculated. These measures were used to assess the reliability of participant responses to computer work of healthy individuals, as well as quantify differences between those with and without chronic pain. We found that individuals with pain activated their neck-shoulder muscles for longer continuous durations than healthy individuals, thus showing an inability to relax their muscles when performing work.

This study is a subset of a larger body of research that examined shoulder time to fatigue during overhead work in an attempt to reduce the prevalence and impact of work-related musculoskeletal problems in the shoulder associated with overhead work, particularly during automobile assembly. Existing evidence suggests that shoulder injuries are diverse in terms of tissues affected and symptoms presented. Furthermore, the cause of these injuries is multifactorial. The work presented here assumes that musculoskeletal injuries of the shoulder mechanism are at least related to, if not caused by, fatigue localized to the shoulder musculature. While the exact relationship between fatigue and injury has not been clearly established, there is consensus among researchers that fatigue plays and important role. Muscular fatigue, therefore, is viewed as a surrogate measure of risk, and task design to avoid fatigue is seen as a rational method to minimize this risk. An experiment to determine the effects of tool weight on shoulder fatigue and performance during overhead work with work/rest cycles was performed. Times to fatigue were derived based on dependent measures including total task duration, controlled maximum muscle contractions, subjective ratings based on Borg's CR-10 RPE scale, electromyogram behavior (MdPF), and hand force performance measures. Experimental findings indicated that duty cycle (percentage of total task cycle time spent working) significantly affected task duration (p<0.0001), changes in maximum voluntary contraction values for the infraspinatus (p<0.05), and the minimum time for any shoulder muscle to fatigue as determined by changes in the EMG power spectrum (p<0.05). Time to fatigue for the mid deltoid as determined by changes in the median frequency of the EMG power spectrum was shown to change significantly (p<0.05) with change in tool weight. Large intersubject variation was observed for the dependent measures, which showed subjects experiencing different levels of fatigue while performing the same task. Limitations of the study and recommendations for future direction are also discussed. / Master of Science

Objetivo Determinar la asociación entre calidad de sueño y otros factores con el dolor músculo esquelético en docentes de la facultad de ciencias de la salud en una universidad privada peruana Material y métodos Se realizó un estudio transversal con un total de 115 docentes universitarios que pertenecían a la facultad de Ciencias de la Salud los cuales respondieron a un cuestionario con 81 preguntas de identificación de dolor músculo esquelético, auto reporte brindado por el PhD Edgar Vieira (7), el cuestionario de calidad de sueño de Pittsburg, y el Inventario de Ansiedad de Beck. En relación con el análisis de múltiples variables, se utilizó regresión de Poisson con varianza robusta, de donde se calcularon PR crudos y ajustados con IC 95%. Resultados Se encuestaron a 115 profesores, con edad media de 41,44 + 10,46 años. El 94% del total de la muestra mostró dolor en una o más partes del cuerpo, mientras que el 90,4% del porcentaje mencionado presentó dolor en cuello o espalda alta o espalda baja. En relación con la calidad de sueño, los que presentaron perturbaciones de sueño de nivel mínimo fueron 72,6%. Se observó que la presencia de dolor músculo esquelético no estuvo asociado con la edad, el sexo ni con algún nivel de calidad de sueño (p >0.05) Conclusiones Aunque nuestro estudio no encontró asociación de dolor músculo esquelético con calidad de sueño, se halló una alta prevalencia de dolor músculo esquelético específicamente en la zona cervical y espalda baja para los docentes de todas las carreras. Además, no se ha encontrado asociación significativa entre ansiedad y dolor músculo esquelético. Se recomienda realizar más investigaciones, de naturaleza longitudinal. / Objective To determine the association between sleep quality and other factors with musculoskeletal pain in faculty of the School of Health Sciences in a Peruvian private University Material and methods A cross-sectional study was carried out with a total of 115 faculty belonging to the School of Health Sciences who answered a questionnaire with 81 musculoskeletal pain identification questions, a self-report provided by the PhD Edgar Vieira (7), the Pittsburg sleep quality questionnaire, and the Beck Anxiety Inventory. In relation to the analysis of multiple variables, Poisson regression with robust variance was used, where crude PR were calculated and adjusted with 95% CI. Results A total of 115 faculty were surveyed, with an average age of 41.44 + 10.46 years. 94% of the total sample showed pain in one or more parts of the body, while 90.4% of the mentioned percentage presented pain in the neck or upper back or lower back. In relation to the quality of sleep, those who presented disturbances of sleep of minimum level were 72.6%. It was observed that the presence of skeletal muscle pain was not associated with age, sex or with any level of quality of sleep (p> 0.05) Conclusions Although our study found no association of skeletal muscle pain with sleep quality, a high prevalence of musculoskeletal pain was found specifically in the cervical area and lower back for Faculty of all careers. In addition, there is no significant association between anxiety and skeletal muscle pain. / Tesis

La calidad de vida es percibida como el equilibrio físico, mental y emocional de la persona, que se puede ver afectada por diferentes factores como la presencia de dolor por trastornos musculo esqueléticos, obesidad, nivel de actividad física y hábito de fumar. En la población del cuerpo general de bomberos voluntarios del Perú estas variables pueden ser favorables o disminuir la calidad de vida. Objetivo: Verificar la asociación entre los factores de salud y la calidad de vida en el Cuerpo General de Bomberos Voluntarios del Perú Métodos: Se realizó un estudio de tipo transversal, observacional y analítico al personal del cuerpo general de bomberos voluntarios del Perú de Lima-Perú. Pertenecientes a la XXV comandancia departamental lima-norte, XXIV comandancia departamental lima Sur y la IV comandancia departamental lima. Se usó el cuestionario SF-36 versión 1 para medir la calidad de vida. El cuestionario nórdico estandarizado para medir la presencia de dolor por trastorno musculo esquelético, el International physical activity questionnaire (IPAQ) para medir el nivel de actividad física y mediante la medición de circunferencia abdominal la presencia de obesidad. Se hizo un análisis de potencia para la muestra estudiada. Se utilizó el T-Student para el análisis de las variables numéricas. Para el análisis de varianzas y comparar las medias de variable de respuesta se usó Anova. Resultados: Participaron 167 personas, la edad promedio fue de 37.5±11.3 años y 140 (83.8%) eran varones. Se encontró que 31% fuma. Así mismo, 141 (83.9%) tienen obesidad abdominal pero más de la mitad presentó un nivel de actividad física alto (57.7%). Dentro de las 8 dimensiones que comprende la calidad de vida, no hubo puntajes menores a 70%. 159 (95.2%) manifestó haber tenido un dolor de origen músculo-esquelético alguna vez en la vida, mientras que 122 (73.9%) reportó tener dolor durante el último año y 99 (61.1%) durante las últimas cuatro semanas. La edad tuvo asociación con la dimensión de fatiga (p=0,014) y bienestar emocional (p=0,002). La variable sexo tuvo evidencia de asociación con la dimensión de limitación debido a salud física (p=0.031); fatiga (p=0.040); y salud general (p=0.047). Siendo el grupo masculino el que tiene puntajes más altos. De la misma manera, el tiempo de servicio como bombero afectó dimensiones como el funcionamiento físico (p=0.013); limitación debido a salud física (p=0.007); funcionamiento social (p=0.006) y dolor (p=0.012). Respecto al reporte de dolor, el haber tenido dolor alguna vez en la vida estuvo asociado con las dimensiones de fatiga (p=0.003); funcionamiento social (p=0.044) y salud general (p=0.010). Mientras que el reporte de dolor en el último año se asoció con esas mismas dimensiones y con la dimensión de dolor (p=0.001). Finalmente, el reporte de dolor en el último mes se asoció con todas las dimensiones mencionadas y con el funcionamiento físico (p=0.009). Las variables de obesidad, fumar y actividad física no tuvieron asociación con ninguna de las 8 dimensiones de calidad de vida. Conclusiones: El presente estudio logró determinar la relación entre los factores de salud asociados a la calidad de vida y encontró asociación con la presencia de dolor por trastorno musculo esquelético, tiempo de bombero, edad y sexo. No se encontró asociación en los factores, obesidad, hábito de fumar y nivel de actividad física. / Quality of life is perceived as the physical, mental and emotional balance of the person, which can be influenced by different factors such as the presence of pain due to musculoskeletal disorders, obesity, level of physical activity, and smoking habits. In the population of the General Volunteer Fire Department of Peru these factors can be favorable or can decrease the quality of life. Objective: Verify the association between health factors and quality of life in the General Volunteer Fire Department of Peru. Methods: A cross-sectional, observational and analytical study was carried out on the staff of the General Volunteer Fire Department of Peru from Lima-Peru, XXV Departmental Lima-North, XXIV Departmental Command Lima-South, and the IV Departmental Command Lima. The SF-36 version 1 questionnaire was used to measure the quality of life. The standardized Nordic questionnaire was used to measure the presence of pain due to musculoskeletal disorders, the International Physical Activity Questionnaire (IPAQ) to measure the level of physical activity, and abdominal circumference was measured to determine the presence of obesity. A power analysis was performed for the sample studied. The T-Student was used for the analysis of the numerical variables. Anova was used for the analysis of variances and comparing the means of the response variable. Results: 167 people participated, the average age was 37.5 ± 11.3 years, 140 (83.8%) were male. It was found that 31% smoke cigarettes. 141 (83.9%) have abdominal obesity, but more than half had a high level of physical activity (57.7%). Within the 8 dimensions of quality of life on the SF-36, no scores below 70% were observed. 159 (95.2%) reported to have had musculoskeletal pain at some time in their life, while 122 (73.9%) reported having pain during the last year and 99 (61.1%) during the last four weeks. Age was associated with the fatigue dimension (p = 0.014) and emotional well-being (p = 0.002). The sex variable was associated with the dimension limitation due to physical health (p = 0.031); fatigue (p = 0.040); and general health (p = 0.047) and the male group was the one with the highest scores. The service time as a firefighter affected dimensions such as physical functioning (p = 0.013); limitation due to physical health (p = 0.007); social functioning (p = 0.006) and pain (p = 0.012). Having had pain at some time in life was associated with the dimensions of fatigue (p = 0.003), social functioning (p = 0.044), and general health (p = 0.010). While pain reported in the last year was also associated with those same dimensions and with the pain dimension in the SF-36 (p = 0.001). Finally, the pain report in the last month was associated with all the mentioned dimensions and with the physical functioning (p = 0.009). The variables of obesity, smoking and physical activity had no association with any of the 8 dimensions of quality of life. Conclusions: The present study was able to determine the relationship between health factors and with quality of life. An association was found between presence of pain due to musculoskeletal disorders, time as a firefighter, age and sex. No association was found in factors of obesity, smoking and level of physical activity. / Tesis

<p>Ill health is unevenly distributed across different groups in society, with the disadvantaged groups displaying higher rates of ill health than the more advantaged groups. The aim of the thesis is to study work-related inequalities in health, and to focus on how income, aspects of the physical and psychosocial work environment, and sense of coherence, individually or jointly, generate inequalities in a number of health outcomes in the Swedish working population. The studies are based on survey data and national registers during the period 1990-2003.</p><p>For cardiovascular disease (CVD) prevalence and mortality, the impact of income was stronger than that of work environment factors. The psychosocial work environment (women and men) and income (men only) were associated with psychological distress. Income (women) and the psychosocial work environment (men) were associated with musculoskeletal pain. Thus, both income and work environment are important in generating health inequalities in the working population.</p><p>A strong sense of coherence (SOC) moderated the effect of physical demands on musculoskeletal pain in both genders. SOC moderates, yet not consistently, the impact of adverse working conditions on psychological distress and musculoskeletal pain. Hence, the results do not fully support the hypothesis that sense of coherence is a global health-protective factor. However, differential vulnerability in terms of the strength of SOC contributed to work-related inequalities in health.</p><p>The risk of stroke was higher for women and men in occupations with low job control than for those with high job control. The risk of intracerebral hemorrhage was highest in women in low job-control occupations, while low job control did not significantly increase the risk of brain infarction in women. Job control was related to mortality from stroke in women, but not in men. The effect of job control on stroke mortality in women was consistent in all classes except for upper non-manuals.</p>

Ill health is unevenly distributed across different groups in society, with the disadvantaged groups displaying higher rates of ill health than the more advantaged groups. The aim of the thesis is to study work-related inequalities in health, and to focus on how income, aspects of the physical and psychosocial work environment, and sense of coherence, individually or jointly, generate inequalities in a number of health outcomes in the Swedish working population. The studies are based on survey data and national registers during the period 1990-2003. For cardiovascular disease (CVD) prevalence and mortality, the impact of income was stronger than that of work environment factors. The psychosocial work environment (women and men) and income (men only) were associated with psychological distress. Income (women) and the psychosocial work environment (men) were associated with musculoskeletal pain. Thus, both income and work environment are important in generating health inequalities in the working population. A strong sense of coherence (SOC) moderated the effect of physical demands on musculoskeletal pain in both genders. SOC moderates, yet not consistently, the impact of adverse working conditions on psychological distress and musculoskeletal pain. Hence, the results do not fully support the hypothesis that sense of coherence is a global health-protective factor. However, differential vulnerability in terms of the strength of SOC contributed to work-related inequalities in health. The risk of stroke was higher for women and men in occupations with low job control than for those with high job control. The risk of intracerebral hemorrhage was highest in women in low job-control occupations, while low job control did not significantly increase the risk of brain infarction in women. Job control was related to mortality from stroke in women, but not in men. The effect of job control on stroke mortality in women was consistent in all classes except for upper non-manuals.

The musculoskeletal disorders have significant health care, social and economic consequences in the factories nowadays. One of the most promising possible solutions is the use of exoskeletons in the workstations. Exoskeletons are assistive wearable robotics connected to the body of a person, which aims to give mechanical power or mobility to the user (Wang, Ikuma, Hondzinski, &amp; de Queiroz, 2017). The objective of this project is to create a realistic CAD model of a passive exoskeleton which will be used in future research to analyse the behaviour of the workers in a virtual environment with and without the exoskeleton. This model will be a virtual representation of the exoskeleton EKSOVest which has been designed to support these workers who have to realize overhead tasks. This virtual representation will be carried out in PTC CREO and exported to IPS IMMA in order to check the viability of this model. To achieve a realistic model, the exoskeleton should have the same characteristics than the real exoskeleton. The objectives of this project will be defined for these characteristics, which are part creation, mechanisms, forces simulation, and parametrization. The parts and the mechanisms will be created and defined in PTC CREO with the same dimensions and behaviour as the real exoskeleton. Furthermore, this report will be focussed mainly in force simulation and the parametrization. The forces of the EKSOVest are generated by two different spring and by a high-pressure spring. To simulate these forces, the equation of these springs will be obtained and introduced in PTC CREO. These equations will be obtained through the regression of a set of points, which will be obtained from the real exoskeleton using a dynamometer. The parametrization will be carried out with the objective to make the virtual model adaptable for every type of mannequins. This parametrization will modify the length of the exoskeleton’s spine bar and the distance between the mechanical arms. These distances will be adapted according to the mannequin’s measures which will be introduced by the user. The measures that have to be introduced by the user are shoulder height, liac spine height, and chest width. In conclusion, it can be said that the regression of the springs obtained are an accurate result which can imitate quite well the forces of this exoskeleton. Furthermore, the results of the parametrization allow the exoskeleton adaptable to any type of dimensions that the mannequin could have. The final model obtained has been exported to IPS IMMA and implemented in a mannequin.

Introduction: Lower extremity (LE) work-related musculoskeletal disorders (WMSDs) are known to occur with cumulative exposure to occupational and personal risks. The objective of this dissertation study was to find if creating a quantifiable risk detection model for the LE was feasible. The primary product of the literature review conducted for this study resulted in focusing the attention of the model development process onto creating the initial model of the LE for assessing knee disorder risk factors. Literature Review: LE occupational disorders affect numerous industries and thousands of people each year by affecting any one of the musculoskeletal systems deemed susceptible by the occupational and personal risk factors involved. Industries known to be affected tend to have labor intensive job descriptions. Some of the numerous industry examples include mining, manufacturing, firefighting, and carpet laying. Types of WMSDs noticed by the literature include bursitis, osteoarthritis, stress fractures, tissue inflammation, and nerve entrapment. In addition to the occupationally related disorders that may develop, occupationally related discomforts were also taken into consideration by this study. Generally, both the disorders and the discomforts can be traced to either a personal or occupational risk factor or both. Personal risk factors noted by the literature include a person's physical fitness and health history (such as past injuries). Meanwhile, occupational risks can be generalized to physical postures, activities, and even joint angles. Prevalence data over a three year interval (2003-2005) has found that LE WMSDs make up on average approximately 7.5% of all the WMSD cases reported to the US Occupational Safety and Health Administration (OSHA). When the literature is refined to the information pertaining to occupational knee disorders, the mean prevalence percentage of the same three year range is about 5%. Mean cost for knee injuries were found to be $18,495 (for the year between 2003 and 2004). Methodology: Developing a risk model for the knee meant using groups of subject matter experts for model development and task hazard analysis. Sample occupational risk data also needed to be gathered for each of a series of tasks so that the model could be validated. These sample data were collected from a sample aircraft assembly plant of a US aerospace manufacturer. Results: Based on the disorder and risk data found in the literature, a knee risk assessment model was developed to utilize observational, questionnaire, and direct measure data collection methods. The final version of this study's knee model has an inventory of 11 risk factors (8 occupational and 3 personal) each with varying degrees of risk exposure thresholds (e.g., high risk, moderate risk, or minimal risk). For the occupational risk assessment portion of the model, the results of task evaluations include both an occupational risk resultant score (risk score) and a task risk level (safe or hazardous). This set of results is also available for a cumulative (whole day) assessment. The personal risk assessment portion only produces a risk resultant score. Validation of the knee risk model reveals statistically (t (34) = 1.512, p = 0.156), that it is functioning as it should and can decide between hazardous and safe tasks. Additionally, the model is also capable of analyzing tasks as a series of cumulative daily events and providing an occupational and personal risk overview for individuals. Conclusion: While the model proved to be functional to the given sample site and hypothetical situations, further studies are needed outside of the aerospace manufacturing environment to continue testing both the model's validity and applicability to other industrial environments. The iterative adjustments generated for the occupational risk portion of the model (to reduce false positives and negatives) will need additional studies that will further evaluate professional human judgment of knee risk against this model's results. Future investigations must also make subject matter experts aware of the minimal risk levels of this knee risk assessment model so that task observational results are equally comparable. Additional studies are moreover needed to assess the intimate nature between variable interactions; especially multiple model defined minimal risks within a single task.

No description available.