Introdução: As Lesões por Esforços Repetitivos (LER) ou Distúrbios Osteomusculares Relacionados ao Trabalho (DORT) são afecções músculo esqueléticas. A enfermagem é uma das categorias da área da saúde mais atingidas por estas, devido aos fatores de risco da profissão. Apresentar desconforto e dor em regiões específicas do corpo, faz parte do cotidiano de muitos destes trabalhadores, que acabam apresentando alterações em sua qualidade de vida. Estes fatores levam ao aparecimento do presenteísmo observado quando o trabalhador está presente no trabalho apesar de doente ou com algum problema físico ou psicológico e ao absenteísmo que ocorre quando este trabalhador falta ao trabalho. Objetivo: Avaliar o impacto de um Curso de Ensino à Distância (EAD) de Prevenção em LER/DORT na qualidade de vida destes trabalhadores e avaliar também desconforto e dor, presenteísmo e absenteísmo. Métodos: Sessenta funcionários da enfermagem de um hospital geral universitário participaram do ensaio clínico, randomizados aleatoriamente em dois grupos.Os critérios de inclusão foram: ser contratado do hospital nas categorias profissionais enfermeiros, técnicos e auxiliares de enfermagem e atuarem em unidades de internação. Foram excluídos trabalhadores com diagnóstico de LER/DORT auto-referido.O grupo intervenção participou de um curso em EAD com duração de 8 horas, composto por estratégias e dicas laborais para a prevenção de LER/DORT, literaturas disponíveis e provas teóricas, o grupo controle foi submetido a uma palestra educativa com duração de 30 minutos, com os mesmos conteúdos do curso em EAD. Foram avaliados antes da intervenção, duas e oito semanas após. Resultados: Quando comparada a qualidade de vida entre os grupos não observamos melhores resultados na percepção do grupo intervenção. O domínio de dor apresentou pior percepção. Presenteísmo foi observado em ambos os grupos, observamos redução do presenteísmo nos grupos sendo no grupo controle uma diferença significativa.Em relação ao desconforto e dor, ambos os grupos apresentaram alta prevalência, houve mudança significativa no grupo controle, com redução na escala do basal para a 8ª semana depois na região das costas inferior. No grupo intervenção não há uma diferença estatisticamente significativa, apesar de haver uma importante redução. Já o absenteísmo apresentou diferença entre os grupos, sendo que no vii grupo intervenção teve redução do número de horas de afastamento por doença. Conclusão: Não há evidência do impacto de um curso de ensino a distância (EAD) de prevenção em LER/DORT na melhora da percepção de qualidade de vida de um grupo de enfermagem. / Introduction: Repetitive Strain Injuries (RSI) or Work-Related Musculoskeletal Disorders (WMSDs) are musculoskeletal disorders. Nursing is one of the health categories that area most affected by these, due to the profession risk factors. Many of these workers show discomfort and pain in specific regions of the body as part of the daily life that end up presenting changes in their quality of life. These factors lead to the appearance of presenteeism observed when the worker is present at work despite being ill or with some physical or psychological problem and to absenteeism that occurs when this worker is absent from work. Objective: To evaluate the effects of a distance learning (DL) course on prevention of RSI and WMSDs in the quality of life of these workers and also to assess discomfort and pain, presenteeism and absenteeism. Methods: Sixty nursing staff from a general university hospital participated in the randomized trial, randomly divided into two groups. The inclusion criteria were: to be a hospital employee in the categories professional nurses, technicians, nurse assistants and to work in hospitalization units. Workers with self-reported diagnosis of RSI/WMSDs were excluded. The intervention group participated in an 8h DL course, consisting of strategies and work tips for the prevention of RSI/ WMSDs, available literature and theoretical evidence, the control group was submitted to a 30 minute educational lecture, with the same content of the DL course. They were evaluated before the intervention, two and eight weeks after. Results: When comparing the quality of life between the groups, the we did not observe better results in the perception of the intervention group. The pain domain presented worse perception. Presenteeism was observed in both groups, we observed reduction of presenteeism in the groups being a significant difference in the control group. Regarding to discomfort and pain, both groups presented a high prevalence, there was a significant change in the control group, with a reduction in the baseline scale to the 8th week later in the lower back region. In the intervention group there is no significant difference statistically, although there is a significant reduction. On the other hand, absenteeism presented a difference between the groups and in the intervention group there was a reduction in the number of hours of sick leave. Conclusion: There is no evidence of the impact of a distance learning prevention course on RSI/WMSDs on the improvement of the perception of the quality of life of a nursing group

Work-related musculoskeletal disorders (WMSDs) due to overexertion and consequently the low back pain (LBP) are one of the most prevalent sources of nonfatal occupational injuries and illnesses in all over the world. In the past several years, the industrial exoskeletons especially the passive ones have been proposed as alternative intervention and assistive devices, which are capable of reducing the risk of WMSDs and LBP. However, more research is warranted to validate the applicability of these exoskeletons. In addition, because the majority of previous studies have been limited to specific lifting tasks using only one type of lift assistive exoskeleton, more research is needed to examine the effect of alteration of different lift-assistive exoskeletons on reducing the activity of back muscles and metabolic reduction. The main objective of this dissertation is to render an overview of three studies that attempt to improve the literature by providing comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (VT-Lowe's Exoskeleton (developed in ARLab at VT), Laevo and SuitX). This dissertation has been composed of three related studies. The first study aimed to investigate and examine the capability of a novel lift assistive exoskeleton, VT-Lowe's exoskeleton, in reducing the peak and mean activity of back and leg muscles. Findings revealed that the exoskeleton significantly decreased the peak and mean activity of back muscles (IL(iliocostalis lumborum) and LT(longissimus thoracis)) by 31.5% and 29.3% respectively for symmetric lifts, and by 28.2% and 29.5% respectively for asymmetric lifts. Furthermore, the peak and mean EMG of leg muscles were significantly reduced by 19.1% and 14.1% during symmetric lifts, and 17.4% and 14.6% during asymmetric lifts. Interestingly, the VT-Lowe's exoskeleton showed higher reduction in activity of back and leg muscles compared to other passive lift-assistive exoskeletons available in the literatures. In the second study, the metabolic cost reduction associated with the use of VT-Lowe's exoskeleton during freestyle lifting was theoretically modelled, validated and corresponding metabolic savings were reported. The metabolic cost and the oxygen consumption results supported the hypothesis that the VT-Lowe's exoskeleton could significantly reduce the metabolic demands (~7.9% on average) and oxygen uptake (~8.7% on average) during freestyle lifting. Additionally, we presented a prediction model for the metabolic cost of exoskeleton during repetitive freestyle lifting tasks. The prediction models were very accurate as the absolute prediction errors were small for both 0% (< 1.4%) and 20% (< 0.7%) of body weight. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in the context of repetitive lifting tasks. The experimental lifting tasks in this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Results of this study demonstrated that using both exoskeletons during dynamic lifting tasks could significantly lower the peak activity of trunk extensor muscles by ~10-28%. In addition, using both exoskeletons could save the energy expenditure by ~4-13% in all conditions tested by partially offsetting the weight of the torso. Such reductions were, though, task-dependent and differed between the two tested exoskeletons. Overall, the results of all three studies in this dissertation showed the capability of passive lift-assistive exoskeletons in reducing the activity of back and leg muscles and providing metabolic savings during repetitive lifting tasks. / Doctor of Philosophy / Low back pain (LBP) due to overexertion is known as one of the most important sources of nonfatal occupational injuries especially for the workers or manual material handlers who are involved in frequent or repetitive lifting tasks. Every year, many workers are temporarily or permanently disabled due to overuse injuries at workplace. In the past several years, industrial exoskeletons have gained growing interest among biomechanist, roboticist, and other human factor researchers as potential assistive devices to reduce the risk of LBP. In general, the industrial exoskeletons are either “passive or “active”; Active exoskeletons are powered by mechanical/electrical motors and actuators, however, the passive exoskeletons often work using cheaper devices such as gas or metal springs, elastic elements, etc. The exoskeletons discussed in this dissertation are categorized as passive rigid lower-back exoskeletons and they function by storing energy in a spring when the wearer bends and returning the stored energy when the wearer lifts. This dissertation consists of three studies that attempt to provide comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (i.e., VT-Lowe’s Exoskeleton, Laevo and SuitX). The first study examined the efficacy of a novel lift-assistive exoskeleton, VT-Lowe’s exoskeleton, in reducing the peak and mean activity of back and leg muscles. The results of this study demonstrated that the exoskeleton reduced the peak and mean activity of back and leg muscles for symmetric and asymmetric lifting tasks. VT-Lowe’s exoskeleton also showed higher reduction in activity of back muscles compared to other passive lift-assistive exoskeletons available in the literature. In the second study, the metabolic cost reduction with VT-Lowe’s exoskeleton was theoretically modeled and the modeling outcomes were compared to metabolic costs measurements when the exoskeleton was worn. The experimental findings of this study supported the applicability of the exoskeleton by significantly reducing the metabolic cost and oxygen uptake during the freestyle repetitive lifting tasks. Moreover, the prediction metabolic cost model of the exoskeleton showed high accuracy as the absolute prediction errors were within 1.5%. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in repetitive lifting tasks. The lifting tasks of this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Findings of this study showed that both exoskeleton significantly lowered the peak activity of back muscles during the dynamic lifting tasks. Moreover, using both exoskeletons provided metabolic cost savings in all of the studies conditions. Overall, results obtained from the three studies in this dissertation verified the capability of these passive lift- vi assistive exoskeleton in reducing the activity of back and leg muscles and providing the metabolic savings during repetitive lifting tasks.