Le but de ce travail est de déterminer les liens éventuels existant entre la force et l’équilibre agoniste / antagoniste des muscles rotateurs médiaux et latéraux de l’articulation scapulohumérale, et la stabilité scapulo-humérale. La première partie de ce travail est un rappel d’anatomie fonctionnelle, de physiologie articulaire et de biomécanique de l’articulation scapulo-humérale, ainsi que des aspects pathologiques en rapport avec la problématique de sa stabilité et de son exploration. La deuxième partie propose une analyse critique de la technique d’exploration de la force musculaire par dynamométrie isocinétique, afin de déterminer un protocole d’évaluation fiable et reproductible. Ainsi, nous choisissons d’utiliser la position d’évaluation la plus reproductible et la plus adaptée pour l’évaluation de sujets pathologiques : la position assise avec 45° d’abduction dans le plan de la scapula avec correction de la gravité. La troisième partie a pour objet de rechercher, à partir d’études cliniques originales, les liens existant entre la force musculaire des rotateurs médiaux et latéraux de l’épaule et l’instabilité antérieure chronique post-traumatique d’une part, et les adaptations de cette force avec certaines sollicitations sportives d’autre part. Bien qu’un déficit de la force musculaire des rotateurs médiaux et latéraux soit associé à l’instabilité antérieure chronique, nos études ne rapportent pas d’association entre le déséquilibre agoniste/antagoniste et l’instabilité antérieure chronique. Dans le cadre de la pratique de sports sollicitant les membres supérieurs, les adaptations de la force, avec une augmentation de la force des muscles rotateurs médiaux et latéraux du côté dominant, sont inconstantes, et surtout, nos résultats ne rapportent aucun déséquilibre agoniste/antagoniste induit par la pratique sportive. En conclusion, notre travail de thèse met en évidence des adaptations de la force musculaire sans perturbation de l’équilibre agoniste/antagoniste des rotateurs médiaux et latéraux de l’articulation scapulo-humérale, associées à l’instabilité scapulo-humérale ou induites par la pratique de sports sollicitant cette articulation. Prenant en compte les limites de notre expérimentation, on peut faire l’hypothèse que les adaptations physiologiques induites par la pratique sportive n’interviendraient pas comme un mécanisme de désadaptation, ou un facteur de risque prédisposant, à l’origine des pathologies de l’articulation scapulo-humérale. Ainsi, notre conclusion serait que l’équilibre agoniste / antagoniste aurait un rôle protecteur de la stabilité articulaire ; la survenue d’un déséquilibre musculaire agoniste / antagoniste serait alors secondaire à une lésion anatomique et marquerait le signe de son évolution longue et/ou péjorative / The aim of this work is to determine the possible links between strength and agonist/antagonist balance of the shoulder internal and external rotators muscle, and the glenohumeral stability. The first part of this work is a reminder of functional anatomy, joint physiology and biomechanics of the glenohumeral joint, and pathological aspects related to the problem of its stability and its exploration. The second part propose a critical analysis of technical exploration of muscular strength by isokinetic dynamometer to determine a reliable and reproducible protocol. We choose to use the more reliable and more suitable position for evaluation of pathological subject: the seated position with 45° of shoulder abduction in the scapular plane, with gravity corrected. The third part is aimed to research, from original clinical studies, the relationship between shoulder internal and external rotators muscle strength and balance, and shoulder instability on the one hand, and adaptations of this strength with sports practice on the other hand. Although a deficit in rotators muscle strength is associated with recurrent anterior instability, our work reporte no association between agonist/antagonist imbalance and recurrent anterior instability. In overhead sports and sports seeking the upper limbs, adaptations of strength, with a rotator strength increase on the dominant side, are inconsistent, and most importantly, our results reporte no agonist/antagonist imbalance induced by the sports practice. In conclusion, this work highlights adaptations in strength and balance of the shoulder internal and external rotators muscle associated with the glenohumeral joint instability, or induced by the sports practice. Tacking into account the limits of our experiment, we can hypothesis that any physiological adaptations induced by sport practice would not intervene as a pathophysiological mechanisms of desadaptation, or not be considered a risk factor predisposing, to glenohumeral joint diseases. Thus, our conclusion is that the agonist/antagonist balance would have a protective role of the joint stability; the occurrence of a muscle agonist / antagonist imbalance may be secondary to an anatomical lesion and mark the sign of its long and/or pejorative evolution

La respiration est un phénomène vital qui implique une synergie entre diverses structures anatomiques qui constituent le thorax. La physiologie articulaire reste un parent pauvre de la physiologie et la littérature concernant la quantification de la cinématique 3D des articulations du thorax durant le mouvement respiratoire est rare. Ce travail se concentre sur le développement et l'application d'une méthodologie permettant de répondre à cet objectif. La méthode développée combine le traitement de données tomodensitométriques réalisées à trois volumes pulmonaires différents et des techniques d'infographies. Les amplitudes (ROMs) et axes de mouvements (axe hélicoïdaux moyen, AHMs) ont été obtenus au niveau des articulations costo-vertébrales de 12 sujets asymptomatiques. En résumé, les amplitudes diminuent graduellement dans les étages inférieurs ; le volume pulmonaire et l'étage costal influencent significativement les amplitudes costales ; l'orientation des AHMs ne diffère pas entre les étages costaux. En complément, la méthode a été appliquée pour un échantillon de 10 patients atteints de mucoviscidose. La condition pathologique influençait significativement les amplitudes de mouvements mais pas l'orientation des AHMs. Enfin, le déplacement sternal, les variations de l'angle sternal et la cinématique des articulations sternocostales a été analysée. Les déplacements angulaires des côtes par rapport au sternum diminuaient dans les étages inférieurs comme au niveau des articulations costo-vertébrales. L'orientation des AHMs des articulations sternocostales ne différait pas entre les étages. Une corrélation linéaire a été mise en évidence entre les déplacements verticaux du sternum et les amplitudes de mouvement costales au niveau costo-vertébral et sternocostal. Ce travail contribue de façon substantielle à la modélisation 3D du thorax humain durant le mouvement respiratoire d'un point de vue qualitatif et quantitatif / Breathing is a vital phenomenon that implies synergy of various anatomical structures that constitute the thorax. Joint physiology remains a relatively poorly-known component of the overall thorax physiology. Quantitative literature related to in vivo thorax kinematics during breathing is scarce. The present work focuses specifically on developing and applying a methodology to reach this goal. The developed method combined processing of CT data obtained at different lung volumes and infographic techniques. Detailed ranges of motion (ROMs) and axes of movement (mean helical axes, MHAs) were obtained at costovertebral joints in 12 asymptomatic subjects; rib ROMs gradually decrease with increasing rib number; lung volume and rib level have a significant influence on rib ROM; MHAs did not differ between rib levels. In addition, the method was applied on a sample of 10 patients with cystic fibrosis. The pathological condition significantly influenced CVJ ROMs while the orientation of the MHAs did not differ. Finally, the sternal displacement, sternal angle variations and sternocostal joints (SCJ at rib1 to 7) kinematics during breathing motion were analyzed. Rib ranges of motion relative to sternum decreased with increasing rib number similarly to CVJ. Orientation of the MHAs did not differ between SCJ levels. A significant linear correlation was demonstrated between sternum vertical displacement and rib ranges of motion at both CVJ and SCJ. The present work substantially contributes to 3D modelling of human thorax in breathing at a joint level both qualitatively and quantitatively

OBJETIVO: Analisar a contribuição da força muscular isocinética de flexores e extensores do joelho dominante e tronco na aquisição da massa óssea das regiões correspondentes a aplicação dessas forças em atletas de futebol feminino (GAF). MÉTODOS: vinte e duas atletas de futebol feminino foram comparadas com 20 controles pareados (GC). O conteúdo mineral ósseo (CMO) e a densidade mineral óssea (DMO) foram avaliados em corpo total, coluna lombar e quadril dominante (fêmur total e colo femoral) pelo software pediátrico do densitômetro Hologic QDR (modelo Discovery, Bedford, MA, USA). Pela análise de corpo total, foram determinadas as variáveis de composição corporal e a massa óssea do membro inferior dominante, tronco e cabeça. A força muscular no movimento de flexão e extensão do joelho e do tronco foi avaliada pelo dinamômetro isocinético Biodex Multi-joint System 3 (Shirley, NY, USA) na velocidade de 60°/s, com 5 repetições do modo concêntrico/excêntrico. As variáveis concêntricas de pico de torque, trabalho na repetição máxima e trabalho total dos flexores e extensores foram considerados. Foram utilizados o teste t de Student para análise entre grupos e os coeficientes de correlação de Pearson e de regressão linear simples para o GAF. RESULTADOS: Os grupos foram semelhantes para idade, peso, altura, raça e ingestão de cálcio (p>0.05), porém o GAF apresentou maior percentual de massa magra e menor percentual de gordura corporal que o GC (p<0.001). Todos os sítios ósseos submetidos à carga mecânica durante o exercício físico apresentaram valores significativamente superiores no GAF, assim como todas as variáveis de força isocinética concêntrica de joelho dominante e tronco (p<0.05 e p<0.001). As variáveis de massa óssea de todas as regiões avaliadas do GAF apresentaram correlações positivas com o peso, índice de massa corporal, massa magra total e do tronco. A DMO das regiões analisadas não apresentou nenhuma correlação significante com as variáveis de força muscular. Porém, todas as variáveis de força de flexão do tronco correlacionaram-se positivamente com o CMO do corpo total e do tronco, assim como as variáveis de extensão do joelho demonstraram associações positivas com o CMO do quadril e do membro inferior dominante. CONCLUSÃO: A força muscular exerceu uma contribuição positiva na aquisição do CMO dos sítios específicos. Esses resultados de correlação positiva entre a força e a quantidade mineral óssea de sítios específicos provêem evidências adicionais de um papel da força muscular na aquisição da massa óssea regional. / OBJECTIVE: to analyze the contribution of isokinetic muscular strength of dominant knee and trunk flexors and extensors in the acquisition of bone mass in the correspondent regions that these forces are applied in female soccer players. METHODS: twenty-two female soccer athletes (GAF) were compared with 20 matched-controls (GC). The bone mineral content (BMC) and bone mineral density (BMD) were evaluated in whole body, lumbar spine and dominant hip (femoral neck and total hip) with the paediatric software of Hologic QDR (Discovery model, Bedford, MA, USA). From whole body scan, the variables of body composition and bone mass of dominant leg, trunk and head were also determined. The muscular strength of flexion and extension movements in dominant knee and trunk were evaluated with the Biodex Multi-joint System 3 (Shirley, NY, USA) with 60°/s, and 5 repetitions at concentric/eccentric mode. The concentric variables peak torque, maximal repetition total work and total work of flexors and extensors were considered. Statistical analysis was performed using Student\'s t-test to compare groups and additionally Pearson\'s correlation coefficient and linear regression analysis to GAF. RESULTS: Both groups were similar regarding age, weight, height, race and calcium intake (p>0.05), however GAF presented a higher percentage of lean body mass and a lower percentage of body fat compared to GC (p<0.001). All loaded sites during exercise had significantly higher values of bone mass for GAF, and so for all isokinetic concentric strength variables of dominant knee and trunk (p<0.05 e p<0.001). Bone mass variables of GAF regions presented positive correlations with weight, body mass index, total and trunk lean mass. The BMD of any region presents significant correlations with variables of strength performance. Nevertheless, all strength variables of trunk flexors were positively correlated with BMC of whole body and trunk, so as knee dominant extensors with BMC of hip and dominant leg. CONCLUSION: muscular strength exerted a positive contribution to BMC acquisition at specifics sites. These results of positive correlation between force and bone mineral quantity of specific sites give us further evidences of the muscle strength role in the acquisition of regional bone mass.

OBJETIVO: Analisar a contribuição da força muscular isocinética de flexores e extensores do joelho dominante e tronco na aquisição da massa óssea das regiões correspondentes a aplicação dessas forças em atletas de futebol feminino (GAF). MÉTODOS: vinte e duas atletas de futebol feminino foram comparadas com 20 controles pareados (GC). O conteúdo mineral ósseo (CMO) e a densidade mineral óssea (DMO) foram avaliados em corpo total, coluna lombar e quadril dominante (fêmur total e colo femoral) pelo software pediátrico do densitômetro Hologic QDR (modelo Discovery, Bedford, MA, USA). Pela análise de corpo total, foram determinadas as variáveis de composição corporal e a massa óssea do membro inferior dominante, tronco e cabeça. A força muscular no movimento de flexão e extensão do joelho e do tronco foi avaliada pelo dinamômetro isocinético Biodex Multi-joint System 3 (Shirley, NY, USA) na velocidade de 60°/s, com 5 repetições do modo concêntrico/excêntrico. As variáveis concêntricas de pico de torque, trabalho na repetição máxima e trabalho total dos flexores e extensores foram considerados. Foram utilizados o teste t de Student para análise entre grupos e os coeficientes de correlação de Pearson e de regressão linear simples para o GAF. RESULTADOS: Os grupos foram semelhantes para idade, peso, altura, raça e ingestão de cálcio (p>0.05), porém o GAF apresentou maior percentual de massa magra e menor percentual de gordura corporal que o GC (p<0.001). Todos os sítios ósseos submetidos à carga mecânica durante o exercício físico apresentaram valores significativamente superiores no GAF, assim como todas as variáveis de força isocinética concêntrica de joelho dominante e tronco (p<0.05 e p<0.001). As variáveis de massa óssea de todas as regiões avaliadas do GAF apresentaram correlações positivas com o peso, índice de massa corporal, massa magra total e do tronco. A DMO das regiões analisadas não apresentou nenhuma correlação significante com as variáveis de força muscular. Porém, todas as variáveis de força de flexão do tronco correlacionaram-se positivamente com o CMO do corpo total e do tronco, assim como as variáveis de extensão do joelho demonstraram associações positivas com o CMO do quadril e do membro inferior dominante. CONCLUSÃO: A força muscular exerceu uma contribuição positiva na aquisição do CMO dos sítios específicos. Esses resultados de correlação positiva entre a força e a quantidade mineral óssea de sítios específicos provêem evidências adicionais de um papel da força muscular na aquisição da massa óssea regional. / OBJECTIVE: to analyze the contribution of isokinetic muscular strength of dominant knee and trunk flexors and extensors in the acquisition of bone mass in the correspondent regions that these forces are applied in female soccer players. METHODS: twenty-two female soccer athletes (GAF) were compared with 20 matched-controls (GC). The bone mineral content (BMC) and bone mineral density (BMD) were evaluated in whole body, lumbar spine and dominant hip (femoral neck and total hip) with the paediatric software of Hologic QDR (Discovery model, Bedford, MA, USA). From whole body scan, the variables of body composition and bone mass of dominant leg, trunk and head were also determined. The muscular strength of flexion and extension movements in dominant knee and trunk were evaluated with the Biodex Multi-joint System 3 (Shirley, NY, USA) with 60°/s, and 5 repetitions at concentric/eccentric mode. The concentric variables peak torque, maximal repetition total work and total work of flexors and extensors were considered. Statistical analysis was performed using Student\'s t-test to compare groups and additionally Pearson\'s correlation coefficient and linear regression analysis to GAF. RESULTS: Both groups were similar regarding age, weight, height, race and calcium intake (p>0.05), however GAF presented a higher percentage of lean body mass and a lower percentage of body fat compared to GC (p<0.001). All loaded sites during exercise had significantly higher values of bone mass for GAF, and so for all isokinetic concentric strength variables of dominant knee and trunk (p<0.05 e p<0.001). Bone mass variables of GAF regions presented positive correlations with weight, body mass index, total and trunk lean mass. The BMD of any region presents significant correlations with variables of strength performance. Nevertheless, all strength variables of trunk flexors were positively correlated with BMC of whole body and trunk, so as knee dominant extensors with BMC of hip and dominant leg. CONCLUSION: muscular strength exerted a positive contribution to BMC acquisition at specifics sites. These results of positive correlation between force and bone mineral quantity of specific sites give us further evidences of the muscle strength role in the acquisition of regional bone mass.