by Luk tze Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 105-111). / Text in English; abstract also in Chinese. / by Luk tze Chung. / Chapter Chapter One --- Introduction / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Work station design --- p.2 / Chapter 1.3 --- Method of study --- p.4 / Chapter 1.4 --- Purpose of study --- p.5 / Chapter 1.5 --- Variables definition --- p.5 / Chapter 1.6 --- Hypotheses --- p.6 / Chapter 1.7 --- Significance of study --- p.6 / Chapter Chapter Two --- Literature Review / Chapter 2.1 --- Biomechanical study on ergonomics problems --- p.7 / Chapter 2.1.1 --- Ergonomics --- p.7 / Chapter 2.1.2 --- Biomechanics --- p.7 / Chapter 2.1.3 --- Force and torque --- p.8 / Chapter 2.1.3.1 --- Lever systems --- p.8 / Chapter 2.1.3.2 --- Torque and moment --- p.8 / Chapter 2.1.4 --- Biomechanics of the back --- p.9 / Chapter 2.1.5 --- Shoulder biomechanics --- p.10 / Chapter 2.2 --- Manual lifting --- p.12 / Chapter 2.2.1 --- Manual handling and musculoskeletal problems --- p.12 / Chapter 2.2.2 --- Strategies for reducing manual handling injuries --- p.13 / Chapter 2.3 --- Method of analysis in ergonomics problems --- p.13 / Chapter 2.3.1 --- Electromyography --- p.13 / Chapter 2.3.1.1 --- Neurophysiology --- p.13 / Chapter 2.3.1.2 --- Electromyography in biomechanics --- p.14 / Chapter 2.3.2 --- Motion analysis --- p.16 / Chapter 2.3.2.1 --- Direct measurement techniques --- p.16 / Chapter 2.3.2.2 --- Indirect measurement using imaging techniques --- p.17 / Chapter 2.4 --- Summary --- p.18 / Chapter Chapter Three --- Method / Chapter 3.1 --- Subjects --- p.19 / Chapter 3.2 --- Position of EMG electrodes --- p.20 / Chapter 3.3 --- Electromyography (EMG) --- p.23 / Chapter 3.4 --- Normalization of EMG --- p.24 / Chapter 3.5 --- Force platform --- p.31 / Chapter 3.6 --- Motion analysis system --- p.33 / Chapter 3.7 --- Calibration of instrument --- p.39 / Chapter 3.7.1 --- EMG --- p.39 / Chapter 3.7.2 --- Force platform --- p.40 / Chapter 3.7.3 --- Motion analysis system --- p.40 / Chapter 3.7.3.1 --- Calibration of displacement and velocity --- p.40 / Chapter 2.7.3.2 --- Calibration of acceleration --- p.40 / Chapter 3.8 --- Work station design --- p.41 / Chapter 3.9 --- Procedure --- p.42 / Chapter 3.10 --- Data analysis --- p.46 / Chapter Chapter Four --- Results / Chapter 4.1 --- EMG data analysis --- p.47 / Chapter 4.1.1 --- MVC testing results --- p.47 / Chapter 4.1.2 --- Results of ANOVA test --- p.48 / Chapter 4.1.2.1 --- Class level information --- p.48 / Chapter 4.1.2.2 --- ANOVA results --- p.49 / Chapter 4.1.2.3 --- Post Hoc test --- p.53 / Chapter 4.2 --- Motion analysis --- p.63 / Chapter 4.2.1 --- Parameters in motion analysis --- p.63 / Chapter 4.2.2 --- Results of ANOVA test --- p.63 / Chapter 4.2.2.1 --- Post Hoc test --- p.68 / Chapter 4.3 --- Force platform data analysis --- p.84 / Chapter 4.3.1 --- Parameters in force platform data analysis --- p.84 / Chapter 4.3.2 --- Result of ANOVA test --- p.84 / Chapter 4.3.2.1 --- Post Hoc test --- p.85 / Chapter 4.4 --- Results of correlation --- p.89 / Chapter Chapter Five --- Discussion and Conclusions / Chapter 5.1 --- EMG signal --- p.90 / Chapter 5.1.1 --- MVC test --- p.90 / Chapter 5.1.2 --- Results of ANOVA in EMG signal --- p.91 / Chapter 5.1.2.1 --- Cervical erector spinae --- p.91 / Chapter 5.1.2.2 --- Trapezius pars descendens --- p.92 / Chapter 5.1.2.3 --- Infraspinatus --- p.93 / Chapter 5.1.2.4 --- Lumbar erector spinae --- p.94 / Chapter 5.2 --- Motion analysis --- p.95 / Chapter 5.2.1 --- Posture --- p.95 / Chapter 5.2.1.1 --- Absolute thigh angle --- p.96 / Chapter 5.2.1.2 --- Absolute arm angle --- p.96 / Chapter 5.2.1.3 --- Absolute chest and abdomen angle --- p.97 / Chapter 5.2.1.4 --- Absolute neck angle --- p.97 / Chapter 5.2.2 --- Force produced by spinae muscle --- p.98 / Chapter 5.3 --- Ground reaction force analysis --- p.99 / Chapter 5.4 --- Correlation analysis --- p.99 / Chapter 5.5 --- Differences between workers and students --- p.100 / Chapter 5.5.1 --- Muscle activity --- p.100 / Chapter 5.5.2 --- Posture . --- p.100 / Chapter 5.6 --- Conclusions --- p.101 / Chapter 5.7 --- Recommendations --- p.102 / References --- p.105 / Appendix --- p.112

Introdução: A trilha da glenoide é determinada pelo contato que a cartilagem da cavidade glenoidal promove na superfície articular da cabeça do úmero em abdução e rotação lateral. É considerada importante parâmetro na tomada de decisão do tipo de tratamento cirúrgico da instabilidade glenoumeral anterior. Os limites da trilha da glenoide foram definidos por meio de estudos em cadáveres ou por exames de imagem, que não contemplam as forças articulares fisiológicas envolvidas no contato articular. Modelos numéricos de elementos finitos têm a capacidade de simular essas forças articulares e seus efeitos no contato entre as superfícies articulares. Objetivo: Avaliar a trilha da glenoide em modelo numérico de elementos finitos do ombro. Métodos: Será construído um modelo numérico de elementos finitos do ombro baseado em exames de imagem de um voluntário. O modelo contemplará o úmero, a escápula, suas respectivas cartilagens articulares e os músculos do manguito rotador e deltóide. O modelo será validado quanto a sua anatomia e fisiologia e terá liberdade de translação em três eixos. A trilha da glenoide será avaliada nas seguintes posições: 0º, 60º, 90º e 120º de abdução, todas a 90º de rotação lateral. Para cada posição serão avaliadas as características de contato articular e medida a trilha da glenoide conforme referências da literatura. Resultados: O valor da trilha da glenoide em 90º de abdução, segundo parâmetros de Yamamoto, foi de 86% do comprimento máximo anteroposterior da cavidade glenoidal antes do carregamento das forças, e de 79% após. A trilha da glenoide em 60º, 90º e 120º de abdução, segundo parâmetros de Omori, correspondeu respectivamente a 71%, 88% e 104% do comprimento anteroposterior de Omori antes do carregamento das forças, e, após, de 76%, 84% e 103%. Conclusão: Foi construído um modelo numérico validado de elementos finitos do ombro adequado para estudo do contato articular. A análise do contato articular desse modelo ratifica o conceito da trilha da glenoide e contribui para sua evolução / Introduction: The glenoid track is determined by the contact of the glenoid on the articular surface of the humeral head in abduction and external rotation. It is considered an important parameter in decision-making on the type of surgical treatment for anterior glenohumeral instability. The limits of the glenoid track were defined through cadaver studies, or by imaging exams, which do not take into account the physiological articular forces involved in the articular contact. Finite elements numerical models are able to simulate these articular forces and their effects on the contact between the articular surfaces. Objective: To evaluate the glenoid track in a finite elements numerical model of the shoulder. Methods: A finite elements numerical model of the shoulder will be made, based on imaging exams of a volunteer. The model will include the humerus, scapula, their respective articular cartilages, and the rotator cuff and deltoid muscles. The model will have its anatomy and physiology validated, and will have freedom of translation in three axes. The glenoid track will be evaluated in the following positions: 0º, 60º, 90º and 120º of abduction, all at 90º external rotation. For each position, characteristics of articular contact will be evaluated, and the glenoid track measured according to the literature references. Results: The value of the glenoid track at 90º abduction, according to the parameters of Yamamoto, was 86% maximum anteroposterior length of the glenoid before loading of forces, and 79% afterwards. The glenoid track at 60º, 90º and 120º of abduction, according to Omori\'s parameters, corresponded, respectively, to 71%, 88% and 104% of Omori\'s anteroposterior length before loading of forces, and 76%, 84% and 103% afterwards. Conclusion: A validated finite elements numerical model of the shoulder suitable for the articular contact evaluation was made. The articular contact analysis ratifies the glenoid track concept and contributes to its evolution