La chute est un problème de santé publique qui touche principalement les personnes âgées. Nos travaux portent sur la caractérisation des stratégies biomécaniques et cognitives impliquées dans le maintien et le rattrapage de l'équilibre et qui permettent à une personne âgée d'éviter de chuter. En particulier, nous nous sommes intéressé à une population âgée, encore autonome et en bonne santé, dans le but d'identifier les personnes à risque et de permettre une intervention le plus tôt possible. Nous avons pu mettre en évidence que, dans cette population, les tests cliniques classiques ne permettent pas de bien discriminer les « chuteurs » des « non-chuteurs » et que le problème de la chute ne réside pas que dans une déficience musculaire mais aussi cognitive et/ou sensorielle qui affecte les réponses biomécaniques de rattrapage. Les tests les plus discriminants sont identifiés et un outil d'évaluation du risque de chute, permettant d'identifier rapidement les déficiences, est proposé. Enfin, nous fournissons des informations sur les mécanismes impliqués dans les pas protectifs, une stratégie d'équilibration prévalente mais peu évaluée dans les tests cliniques / Falling is a common and concerning health problem for the elderly population. This research work focuses on the characterization of the biomechanical and cognitive strategies involved in the balance maintain and balance recovery that help elderly to avoid a fall. Particularly, we interested in a community-dwelling elderly population, in order to identify the persons who are at risk of fall and suggest a forward preventive intervention. We show, for this population, that usual clinical tests do not well discriminate between “fallers” and “non-fallers” and that the fall problem is more concerned by cognitive and/or sensorial troubles than by muscular troubles that affect biomechanical responses. The most discriminant tests are identified and a risk of fall assessment tool is suggested to give informations about the deficient mechanisms. Finally, we provide informations about the mechanisms involved in protective steps, a prevalent balance strategy which not used in balance clinical assessments

Les mouvements volontaires sont accompagnés par des ajustements posturaux anticipateurs (APAs). Leur rôle consiste à prévenir et à compenser de possibles perturbations du corps provoquées par l’exécution du mouvement. Des études antérieures ont montré que la coordination posture / mouvement est modifiée selon que le mouvement est exécuté le plus rapidement possible en réponse à un signal externe (réactif :TRS), ou que le mouvement est auto-initié (prédictif :AI). L’objectif de ce travail est d’examiner le mode de coordination posture / mouvement impliqué dans une situation d’anticipation-coïncidence (AC) lors de l’exécution de mouvements simples et complexes, et ensuite, comparer ce mode aux modes TRS et AI. Trois études expérimentales ont été menées pour vérifier si : (1) les modes de coordination, obtenus sur des gestes simples, s’étendent à des mouvements complexes ; (2) le mode de coordination en AC dépend des caractéristiques temporelles du mobile utilisé dans la tâche ; (3) les commandes impliquant les APAs et le mouvement focal sont associées ou dissociées en fonctions des contraintes temporelles TRS et AC. Ainsi, nous avons démontré que : (1) les stratégies de coordination posture / mouvement s’appliquent sur les mouvements complexes ; (2) la prédictibilité du moment de déclenchement dans la condition AC rapproche celle-ci de la situation AI ; (3) les différences de coordination entre les conditions réactive (TRS) et prédictives (AC, AI) sont liées à des différences dans les mécanismes de préparation consistant à dissocier les commandes posturales et focales en situation prédictive et à associer ces commandes dans la situation réactive. Les implications théoriques qui émergent de ces résultats sont discutées. / Voluntary movements are generally accompanied by anticipatory postural adjustments (APAs). They are centrally generated as a feedforward mechanism to counteract the mechanical effects of predicted balance perturbations. Previous studies showed that the coordination between posture and movement is modified depending on whether the movement is performed in a reactive temporal pressure (TRS) or in a self-initiated (AI) manner. The aim of this thesis is to examine the coordination of posture and movement in anticipation-coincidence (AC) timing tasks in simple and complex movements, and then to compare this mode to the TRS and AI modes. Three experiments was achieved to verify : (1) whether simple movement coordination modes can be extended to complex movements ; (2) whether the temporal characteristics of the mobile used in the task modifies the coordination in AC condition ; (3) to which extent the motor commands of APAs and the focal movement are coupled in response to the TRS and AC temporal pressures. Results show that: (1) the different strategies of coordination between posture and movement are extended to the complex tasks; (2) the predictable timing of movement execution in the AC condition generates behaviours closer to those observed in AI condition; (3) the differences in the coordination between the reactive (TRS) and the predictive (AC, AI) conditions are related to the difference in the preparatory processes which consists on the dissociation of postural and focal commands in the predictive situations, and the association of this motor commands in the reactive situation. Theoretical implications emerging from these results are discussed.

A falha na estabilidade escapular e no ritmo escápulo-umeral são associadas ao risco de lesão no complexo do ombro. Apesar de se saber que a estabilização ativa dos músculos escapulares é fundamental para evitar disfunções ainda pouco se sabe sobre como o controle postural no complexo do ombro ocorre e como tais mecanismos poderiam auxiliar na estabilização da articulação perante uma tarefa. Será que há ajustes posturais antecipatórios (APA) e compensatórios (APC) nos músculos escapulares (serrátil anterior, trapézio inferior e trapézio superior) em tarefas motoras que envolvem o movimento dos membros superiores? Como as ações motoras modulam a resposta postural dos músculos escapulares e globais (músculos do tronco e membros inferiores) para estabilizar e orientar o corpo? O objetivo deste estudo foi analisar a existência dos ajustes posturais antecipatórios e compensatórios nos músculos escapulares e globais em sujeitos ativos saudáveis em tarefas de membros superiores. Para tal, participaram 70 indivíduos ativos saudáveis (18 mulheres e 52 homens, 28,0±7,2 anos, 70,5±13,4 kg e 1,72±0,07 m). Foi mensurada atividade eletromiográfica do músculo focal Deltóide Anterior, músculos escapulares (Serrátil Anterior, Trapézio Superior, Trapézio Inferior) e músculos globais (Reto Abdominal, Eretor Longuíssimo, Reto Femoral, Bíceps Femoral, Gastrocnêmio, Tibial Anterior) em 4 tarefas de membros superiores (abdução no plano escapular, adução, flexão e extensão) executadas com halteres de massa 1kg e 3kg. Os resultados mostraram a existência de ajustes posturais dos músculos escapulares (p<0,001); a tarefa e massa influenciaram nos ajustes posturais antecipatórios e compensatórios (p<0,001); as tarefas de adução versus extensão não apresentaram diferença entre si na atividade muscular dos músculos escapulares durante os ajustes posturais antecipatórios e compensatórios (p>0,05); as tarefas de abdução versus flexão são semelhantes com massa 1kg (p>0,05), mas se tornam diferentes com massa 3kg (p<0,001) com relação a atividade muscular dos músculos escapulares e globais; nas tarefas de flexão e abdução os maiores ajustes posturais foram dos músculos escapulares (Serrátil Anterior e Trapézio Inferior) (p<0,001); nas tarefas de adução e extensão os maiores são dos músculos globais (p<0,001); os ajustes posturais antecipatórios e compensatórios foram maiores nos músculos escapulares Serrátil Anterior e Trapézio Inferior do que no músculo focal Deltóide Anterior (p<0,001); existiu modulações nos tipos e níveis de APA e APC nas tarefas de membros superiores (p<0,001). Em conclusão, temos uma associação de ajustes posturais como mecanismos de estabilização e orientação do ombro em tarefas dos membros superiores. No entanto, a intensidade e modulação dos ajustes posturais são afetadas pela tarefa e massa. Acreditamos que a atividade muscular dos músculos escapulares esteja diretamente associada a necessidade de minimizar a perturbação para a manutenção da orientação e estabilidade segmento (ombro), assim como atividade dos músculos globais está associada a manutenção da estabilidade e orientação do corpo. Esses achados podem ser utilizados para futuros estudos comparando sujeitos com disfunção e saudáveis e assim entender se há atividade anormal dos músculos escapulares nos períodos de ajustes posturais antecipatórios e compensatórios e se esta atividade muscular contribui para disfunção do complexo do ombro / The failure of scapular stability and scapulohumeral rhythm is associated with the risk of injury to the shoulder complex. Although it is known that the active stabilization of the scapular muscles is fundamental to avoid dysfunctions, little is known about how postural control in the shoulder complex occurs and how such mechanisms could help stabilize the joint before a task. Are there anticipatory postural adjustments (APA) and compensatory (CPA) in the scapular muscles (serratus anterior, lower trapezius and upper trapezius) in motor tasks involving the movement of the upper limbs? How do motor actions modulate the postural response of the scapular and global muscles (trunk muscles and lower limbs) to stabilize and guide the body? The objective of this study was to analyze the existence of anticipatory and compensatory postural adjustments in the scapular and global muscles in healthy subjects in upper limb tasks. To do this, participated 70 healthy active individuals (18 women and 52 men, 28,0±7,2 years 70,5±13,4 kg and 1,72±0,07 m). It Was measured electromyographic activity of focal muscle (Deltoid Anterior), scapular muscles (Serratus Anterior, Upper Trapezius, Lower Trapezius) and global muscles (Rectus Abdominis, Longissimus, Rectus Femoris, Biceps Femoris, Gastrocnemius, Tibial Anterior) was measured in 4 upper limb tasks (abduction in the scapular plane, adduction, flexion and extension) performed with dumbbells of 1kg and 3kg mass. The results showed the existence of postural adjustments of the scapular muscles (p <0.001); the task and mass influenced the anticipatory and compensatory postural adjustments (p <0.001); the tasks of adduction versus extension did not difference among themselves in the muscular activity of the scapular muscles during the anticipatory and compensatory postural adjustments (p> 0.05); the abduction versus flexion tasks are similar with mass 1kg (p> 0.05), but become different with mass 3kg (p <0.001) in relation to muscular activity of the scapular and global muscles; during flexion and abduction tasks, the greatest postural adjustments were the scapular muscles (Serratus Anterior and Lower Trapezius) (p <0.001); during adduction and extension tasks, the largest of the global muscles (p <0.001); anticipatory and compensatory postural adjustments were higher in the serratus anterior and lower trapezius scapula muscles than in the anterior deltoid focal muscle (p <0.001); there were modulations in the types and levels of APA and CPA in upper limb tasks (p <0.001). In conclusion, we have an association of postural adjustments as mechanisms of stabilization and orientation of the shoulder in tasks of the upper limbs. However, the intensity and modulation of postural adjustments are affected by task and mass. We believe that the muscular activity of the scapular muscles is directly associated with the need to minimize the perturbation to the maintenance of the orietantion and stability segment (shoulder), as well as overall muscle activity is associated with maintaining stability and body orientation. These findings can be used for future studies comparing subjects with dysfunction and health and thus to understand if there is abnormal activity of the scapular muscles in the periods of anticipatory and compensatory postural adjustments and if this muscular activity contributes to dysfunction of the shoulder complex

Made available in DSpace on 2014-06-11T19:30:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-08-21Bitstream added on 2014-06-13T20:40:47Z : No. of bitstreams: 1 ferreira_dma_dr_rcla.pdf: 659123 bytes, checksum: baf4d8518bae6e1d0b27e68eae1725f9 (MD5) / O objetivo deste estudo foi avaliar as alterações estáticas e dinâmicas em pacientes com escoliose idiopática na posição ortostática, sem e com inclinação lateral com restrição associadas ou não as mudanças unilaterais de calços. O grupo experimental foi constituído por pacientes com escoliose idiopática com curva dupla (³ 10°) e o grupo controle por participantes sem escoliose na mesma faixa etária (13-24 anos). Foram utilizadas três câmeras de vídeo, 18 marcadores fixados em referências anatômicas dos participantes, dois calços, de 1 e de 3 cm de altura e uma escala para restrição e padronização da inclinação lateral. As tentativas foram realizadas aleatoriamente, nas condições sem calço ou com calço baixo ou alto sob o pé direito e esquerdo e nas tarefas, estática (15 segundos) ou dinâmica (5 movimentos de inclinação lateral para direita ou esquerda). Foram calculados os ângulos posturais: alfa 1 (torácico alto), alfa 2 (torácico médio), alfa 3 (tóraco-lombar) e alfa 4 (lombar) e os ângulos segmentares: beta 1 (ombros), beta 2 (escápulas), beta 3 (pelves) e beta 4 (joelhos). Na situação estática, os grupos e os calços tiveram uma maior influência nos ângulos posturais tóracolombar e lombar e nos ângulos segmentares da pelve e do joelho. Na situação dinâmica sem calço, nenhuma diferença foi observada entre grupos, porém o calço associado aos movimentos de inclinação lateral provocou ajustes posturais compensatórios nos ângulos posturais alfas e segmentares betas, sendo que as diferenças foram maiores com o calço alto nos pacientes com escoliose, indicando um possível mecanismo corretivo. Estas alterações posturais tanto estáticas como dinâmicas, indicam a busca de uma nova organização estrutural e equilíbrio do tronco, sendo que os segmentos superiores foram mais influenciados na condição dinâmica... / The purpose of this study was to evaluate static and dynamic changes in patients with idiopathic scoliosis in the orthostatic position, with and without restricted lateral inclination associated with or not unilateral changes of shoe lifting. The experimental group was constituted by patients with idiopathic scoliosis with double curve (³ 10°) and the control group by participants without scoliosis with the same age (13-24 years). Three video cameras were used, with 18 markers fixed on the participants' anatomical references, along with two shoe lifts, 1 and 3 cm of height, and a scale for restriction and standardization of the lateral inclination. The trails were accomplished randomly, in the conditions without or with shoe lift (low or high) under the right and left foot and in the tasks, static (15 seconds) or dynamic (5 movements of lateral inclination for right or left). Postural angles: alpha 1 (thoracic high), alpha 2 (thoracic medium), alpha 3 (thoracolumbar) and alpha 4 (lumbar); and segmental angles: beta 1 (shoulders), beta 2 (scapulas), beta 3 (pelvis) and beta 4 (knees) were calculated. In the static condition, group and shoe lift mostly influenced the postural angles, thoracic-lumbar and lumbar, and the segmental angles of the pelvis and knee. In the dynamic condition without shoe lift, no difference was observed between groups, however, with shoe lift.and lateral inclination compensatory postural adjustments were observed in the postural alpha angles and segmental beta angles, with the largest differences observed in the condition with the high shoe lifting in the patients with scoliosis, indicating a possible corrective mechanism. These, static and dynamics, postural changes suggest a new structural organization and equilibrium of the trunk, with the trunk upper segments being the ones more influenced by the dynamic condition with low and high shoe lifting whereas... (Complete abstract click electronic access below)

A falha na estabilidade escapular e no ritmo escápulo-umeral são associadas ao risco de lesão no complexo do ombro. Apesar de se saber que a estabilização ativa dos músculos escapulares é fundamental para evitar disfunções ainda pouco se sabe sobre como o controle postural no complexo do ombro ocorre e como tais mecanismos poderiam auxiliar na estabilização da articulação perante uma tarefa. Será que há ajustes posturais antecipatórios (APA) e compensatórios (APC) nos músculos escapulares (serrátil anterior, trapézio inferior e trapézio superior) em tarefas motoras que envolvem o movimento dos membros superiores? Como as ações motoras modulam a resposta postural dos músculos escapulares e globais (músculos do tronco e membros inferiores) para estabilizar e orientar o corpo? O objetivo deste estudo foi analisar a existência dos ajustes posturais antecipatórios e compensatórios nos músculos escapulares e globais em sujeitos ativos saudáveis em tarefas de membros superiores. Para tal, participaram 70 indivíduos ativos saudáveis (18 mulheres e 52 homens, 28,0±7,2 anos, 70,5±13,4 kg e 1,72±0,07 m). Foi mensurada atividade eletromiográfica do músculo focal Deltóide Anterior, músculos escapulares (Serrátil Anterior, Trapézio Superior, Trapézio Inferior) e músculos globais (Reto Abdominal, Eretor Longuíssimo, Reto Femoral, Bíceps Femoral, Gastrocnêmio, Tibial Anterior) em 4 tarefas de membros superiores (abdução no plano escapular, adução, flexão e extensão) executadas com halteres de massa 1kg e 3kg. Os resultados mostraram a existência de ajustes posturais dos músculos escapulares (p<0,001); a tarefa e massa influenciaram nos ajustes posturais antecipatórios e compensatórios (p<0,001); as tarefas de adução versus extensão não apresentaram diferença entre si na atividade muscular dos músculos escapulares durante os ajustes posturais antecipatórios e compensatórios (p>0,05); as tarefas de abdução versus flexão são semelhantes com massa 1kg (p>0,05), mas se tornam diferentes com massa 3kg (p<0,001) com relação a atividade muscular dos músculos escapulares e globais; nas tarefas de flexão e abdução os maiores ajustes posturais foram dos músculos escapulares (Serrátil Anterior e Trapézio Inferior) (p<0,001); nas tarefas de adução e extensão os maiores são dos músculos globais (p<0,001); os ajustes posturais antecipatórios e compensatórios foram maiores nos músculos escapulares Serrátil Anterior e Trapézio Inferior do que no músculo focal Deltóide Anterior (p<0,001); existiu modulações nos tipos e níveis de APA e APC nas tarefas de membros superiores (p<0,001). Em conclusão, temos uma associação de ajustes posturais como mecanismos de estabilização e orientação do ombro em tarefas dos membros superiores. No entanto, a intensidade e modulação dos ajustes posturais são afetadas pela tarefa e massa. Acreditamos que a atividade muscular dos músculos escapulares esteja diretamente associada a necessidade de minimizar a perturbação para a manutenção da orientação e estabilidade segmento (ombro), assim como atividade dos músculos globais está associada a manutenção da estabilidade e orientação do corpo. Esses achados podem ser utilizados para futuros estudos comparando sujeitos com disfunção e saudáveis e assim entender se há atividade anormal dos músculos escapulares nos períodos de ajustes posturais antecipatórios e compensatórios e se esta atividade muscular contribui para disfunção do complexo do ombro / The failure of scapular stability and scapulohumeral rhythm is associated with the risk of injury to the shoulder complex. Although it is known that the active stabilization of the scapular muscles is fundamental to avoid dysfunctions, little is known about how postural control in the shoulder complex occurs and how such mechanisms could help stabilize the joint before a task. Are there anticipatory postural adjustments (APA) and compensatory (CPA) in the scapular muscles (serratus anterior, lower trapezius and upper trapezius) in motor tasks involving the movement of the upper limbs? How do motor actions modulate the postural response of the scapular and global muscles (trunk muscles and lower limbs) to stabilize and guide the body? The objective of this study was to analyze the existence of anticipatory and compensatory postural adjustments in the scapular and global muscles in healthy subjects in upper limb tasks. To do this, participated 70 healthy active individuals (18 women and 52 men, 28,0±7,2 years 70,5±13,4 kg and 1,72±0,07 m). It Was measured electromyographic activity of focal muscle (Deltoid Anterior), scapular muscles (Serratus Anterior, Upper Trapezius, Lower Trapezius) and global muscles (Rectus Abdominis, Longissimus, Rectus Femoris, Biceps Femoris, Gastrocnemius, Tibial Anterior) was measured in 4 upper limb tasks (abduction in the scapular plane, adduction, flexion and extension) performed with dumbbells of 1kg and 3kg mass. The results showed the existence of postural adjustments of the scapular muscles (p <0.001); the task and mass influenced the anticipatory and compensatory postural adjustments (p <0.001); the tasks of adduction versus extension did not difference among themselves in the muscular activity of the scapular muscles during the anticipatory and compensatory postural adjustments (p> 0.05); the abduction versus flexion tasks are similar with mass 1kg (p> 0.05), but become different with mass 3kg (p <0.001) in relation to muscular activity of the scapular and global muscles; during flexion and abduction tasks, the greatest postural adjustments were the scapular muscles (Serratus Anterior and Lower Trapezius) (p <0.001); during adduction and extension tasks, the largest of the global muscles (p <0.001); anticipatory and compensatory postural adjustments were higher in the serratus anterior and lower trapezius scapula muscles than in the anterior deltoid focal muscle (p <0.001); there were modulations in the types and levels of APA and CPA in upper limb tasks (p <0.001). In conclusion, we have an association of postural adjustments as mechanisms of stabilization and orientation of the shoulder in tasks of the upper limbs. However, the intensity and modulation of postural adjustments are affected by task and mass. We believe that the muscular activity of the scapular muscles is directly associated with the need to minimize the perturbation to the maintenance of the orietantion and stability segment (shoulder), as well as overall muscle activity is associated with maintaining stability and body orientation. These findings can be used for future studies comparing subjects with dysfunction and health and thus to understand if there is abnormal activity of the scapular muscles in the periods of anticipatory and compensatory postural adjustments and if this muscular activity contributes to dysfunction of the shoulder complex

L’objectif de cette thèse était de mettre en évidence les différentes stratégies adaptatives posturales et motrices face à une contrainte temporelle chez le jeune adulte et la personne âgée lors de la production d’un mouvement complexe mobilisant l’ensemble du corps. Le modèle de mouvement choisi est composé d’une flexion rapide de la cuisse dominante associée à une extension simultanée de l’index ipsilatéral. Les résultats de la première étude ont montré que le mode de déclenchement de la commande motrice modifiait l’organisation posturale du mouvement. La durée des APA associés à la flexion de la cuisse était plus courte en condition de pression temporelle forte (condition temps de réaction, TR) qu’en condition de pression temporelle faible (condition auto-initiée, AI). Cette diminution de la durée des APA était compensée par une augmentation du pic de déplacement anticipateur du centre des pressions (CP) vers la jambe oscillante. De cette façon, la stabilité dynamique ainsi que la performance motrice restaient inchangées. Les résultats de la deuxième étude ont montré que les sujets âgés étaient également capables de réduire la durée des APA en condition TR. Cependant, au contraire des sujets jeunes, ils ne compensaient pas cette diminution par une augmentation du déplacement anticipé du CP. La stabilité dynamique au moment du décollement du pied était dégradée dans cette population. Par ailleurs, l’effet de la pression temporelle sur la synchronisation motrice ne changeait pas avec l’avancée en âge. Cependant, l’erreur de synchronisation était plus importante chez les âgés que chez les jeunes, en condition AI uniquement. Enfin, l’étude 3 a montré que la modification transitoire des propriétés mécaniques des membres inférieurs (par l’addition d’une charge de 5 kg aux chevilles) affectait l’ordre de synchronisation du mouvement, en condition TR uniquement. En présence d’une charge, les sujets semblent basculer d’un mode de synchronisation de type « réactif » vers un mode « prédictif », ce qui leur permettait de maintenir une précision de synchronisation optimale. En revanche, le mode de contrôle des APA ne changeait pas. Il semble donc que le mode de contrôle des APA et de la synchronisation des mouvements puissent être dissociés selon les contraintes biomécaniques imposées par l’expérimentation. L’ensemble de ces résultats met en évidence la capacité du SNC à moduler l’ordre temporel de la synchronisation du mouvement ainsi que les paramètres spatio-temporels des APA dans le but d’assurer une coordination temporelle et une stabilité dynamique optimales. / This work aimed to investigate the adaptive postural and motor strategies developed by young and elderly healthy subjects during a complex task involving the whole body when facing a temporal pressure constraint. The motor task chosen was a simultaneous rapid leg flexion paired with ipsilateral finger index extension. Results of the first study showed that the mode of triggering of movement modifies the postural organization of the leg flexion. The APA duration associated with leg flexion was shorter in the reaction-time (RT, high temporal pressure) condition as compared to the self-initiated (SI, low temporal pressure) condition. This APA shortening was compensated by an increase of APA amplitude so that the mediolateral (ML) stability and the motor performance were both unchanged. Results of the second study showed that elderly subjects were unable to compensate this APA shortening by an increase of anticipatory ML centre-of-pressure displacement. Dynamic stability at foot-off was degraded in this population, with a consequent increased risk of ML imbalance and falling. Besides, the effect of temporal pressure on motor synchronization was not affected by ageing. Of particular importance, the synchronization error was greater in elderly than in young subjects, but in the SI condition only. Finally, the third study showed that transitory changes in the mechanical properties of the lower limbs (by ankle loading) affect the order of movement synchronization, but in the RT condition only. With ankle loading, subjects thus switched from a “reactive” to a “predictive” mode of synchronization allowing then to maintain an optimal synchronization. In contrast, ankle loading did not modify the mode of control of the APA. Therefore, it seems that the mode of control of APA and of movement synchronization can be decorrelated according to the biomechanical constraints. These results provide novel insights into the capacity of the CNS to modulate motor synchronization and APA spatio-temporal features to ensure optimal motor coordination and dynamic stability across ages.

Orientador: José angelo Barela / Banca: Ana Maria Pellegrini / Banca: Cláudia Regina Sgobbi de Faria / Banca: Paula Hentschel Lobo da Costa / Banca: Rúben de Faria Negrão Filho / Resumo: O objetivo deste estudo foi avaliar as alterações estáticas e dinâmicas em pacientes com escoliose idiopática na posição ortostática, sem e com inclinação lateral com restrição associadas ou não as mudanças unilaterais de calços. O grupo experimental foi constituído por pacientes com escoliose idiopática com curva dupla (³ 10°) e o grupo controle por participantes sem escoliose na mesma faixa etária (13-24 anos). Foram utilizadas três câmeras de vídeo, 18 marcadores fixados em referências anatômicas dos participantes, dois calços, de 1 e de 3 cm de altura e uma escala para restrição e padronização da inclinação lateral. As tentativas foram realizadas aleatoriamente, nas condições sem calço ou com calço baixo ou alto sob o pé direito e esquerdo e nas tarefas, estática (15 segundos) ou dinâmica (5 movimentos de inclinação lateral para direita ou esquerda). Foram calculados os ângulos posturais: alfa 1 (torácico alto), alfa 2 (torácico médio), alfa 3 (tóraco-lombar) e alfa 4 (lombar) e os ângulos segmentares: beta 1 (ombros), beta 2 (escápulas), beta 3 (pelves) e beta 4 (joelhos). Na situação estática, os grupos e os calços tiveram uma maior influência nos ângulos posturais tóracolombar e lombar e nos ângulos segmentares da pelve e do joelho. Na situação dinâmica sem calço, nenhuma diferença foi observada entre grupos, porém o calço associado aos movimentos de inclinação lateral provocou ajustes posturais compensatórios nos ângulos posturais alfas e segmentares betas, sendo que as diferenças foram maiores com o calço alto nos pacientes com escoliose, indicando um possível mecanismo corretivo. Estas alterações posturais tanto estáticas como dinâmicas, indicam a busca de uma nova organização estrutural e equilíbrio do tronco, sendo que os segmentos superiores foram mais influenciados na condição dinâmica... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to evaluate static and dynamic changes in patients with idiopathic scoliosis in the orthostatic position, with and without restricted lateral inclination associated with or not unilateral changes of shoe lifting. The experimental group was constituted by patients with idiopathic scoliosis with double curve (³ 10°) and the control group by participants without scoliosis with the same age (13-24 years). Three video cameras were used, with 18 markers fixed on the participants' anatomical references, along with two shoe lifts, 1 and 3 cm of height, and a scale for restriction and standardization of the lateral inclination. The trails were accomplished randomly, in the conditions without or with shoe lift (low or high) under the right and left foot and in the tasks, static (15 seconds) or dynamic (5 movements of lateral inclination for right or left). Postural angles: alpha 1 (thoracic high), alpha 2 (thoracic medium), alpha 3 (thoracolumbar) and alpha 4 (lumbar); and segmental angles: beta 1 (shoulders), beta 2 (scapulas), beta 3 (pelvis) and beta 4 (knees) were calculated. In the static condition, group and shoe lift mostly influenced the postural angles, thoracic-lumbar and lumbar, and the segmental angles of the pelvis and knee. In the dynamic condition without shoe lift, no difference was observed between groups, however, with shoe lift.and lateral inclination compensatory postural adjustments were observed in the postural alpha angles and segmental beta angles, with the largest differences observed in the condition with the high shoe lifting in the patients with scoliosis, indicating a possible corrective mechanism. These, static and dynamics, postural changes suggest a new structural organization and equilibrium of the trunk, with the trunk upper segments being the ones more influenced by the dynamic condition with low and high shoe lifting whereas... (Complete abstract click electronic access below) / Doutor

Made available in DSpace on 2016-12-06T17:06:53Z (GMT). No. of bitstreams: 1 Renato Claudino.pdf: 1814234 bytes, checksum: b700b54b51ad2feb7a15021f31ae2a11 (MD5) Previous issue date: 2012-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / With advancing age, the human body suffers morphological and functional changes, which lead the postural instability in elderly people. And an important factor in this, are linked to the inappropriate uses of postural adjustments strategies: anticipatory postural adjustment (APA) and compensatory postural adjustments (CPA). Such strategies deal with an ability to respond effectively to a possible loss of balance and minimize the negative consequences of it. Although the difficulties in maintaining balance in the elderly to be known, strategies of postural adjustment, in the face of external perturbations are still scarce. Therefore, the aim of this study was to investigate the APAs and CPAs and their inter-relationships in groups of elderly with and without falls. For this purpose, two groups of 20 elderly participants (with and without history of falls) and 20 young subjects received external perturbations of posture in the frontal plane, through the impact of a pendulum on the right shoulder of the individuals in the standing position, under two conditions: unpredictable and predictetable. The electromyography activity (EMG) of lateral ventral and dorsal postural muscles by recording and integrated (&#8747;EMG) in the typical windows for these strategies, and displacement of body center of pressure (COP). The postural disturbance occurred in the medial-lateral direction, through the impact of a pendulum on the right shoulder of individuals under two conditions: unpredictable and predictable. The results showed the elderly groups (with and without falls) had, in general, smaller amplitude activation (&#8747;EMG) of the CPAs to the dorsal and lateral studied in the unpredictable conditions. The elderly showed changes in the pattern of synergistic lateral muscles compared to the group of young individuals. There was a greater COP displacement in the predictable condition provided for groups of elderly patients with falls compared to the young. The results of this study indicate that the decrease in muscle activity in the elderly groups against disturbances of posture, especially the lateral muscles, may leave these individuals susceptible to falls. Therefore, research and training programs/training or treatment designed to restoring balance in the elderly by improving the activation of the lateral muscles must be developed. / Com o avançar da idade, o corpo humano sofre alterações morfológicas e funcionais, que acarretam grande instabilidade postural em idosos. E um fator importante desta, esta vinculada ao uso inadequado das estratégias de ajustes posturais: o ajuste postural antecipatório (APA) e compensatório (APC). Essas estratégias tratam da capacidade de um indivíduo em responder efetivamente a uma possível perda de equilíbrio. Embora, a dificuldade na manutenção do equilíbrio em idosos seja conhecida, estudos sobre as estratégias de ajuste postural frente a perturbações externas da postura nessa população ainda são escassos. Portanto, o objetivo desse estudo foi investigar os APAs e CPAs e suas inter-relações em idosos com e sem quedas. Para tanto, dois grupos de 20 idosos cada (sem e com histórico de quedas) e 20 indivíduos jovens receberam perturbações externas da postura no plano frontal, através do impacto de um pêndulo no ombro direito dos indivíduos na posição em pé, sob condições não prevista e prevista. As atividades eletromiográficas dos músculos posturais laterais, ventrais e dorsais foram registradas e integradas (&#8747;EMG) nas janelas de tempo típicas para as estratégias de ajuste postural assim como o deslocamento do centro de pressão corporal (COP). De forma geral, os dois grupos de idosos apresentaram, menor amplitude de ativação (&#8747;EMG) muscular nas janelas dos APCs para os músculos laterais e dorsais na condição não prevista. Idosos também apresentaram alteração no padrão sinérgico dos músculos laterais quando comparados ao grupo de indivíduos jovens. Houve um maior deslocamento do COP na condição prevista para os grupos de idosos com quedas quando comparados aos jovens. Os resultados desse estudo indicam que a diminuição da atividade muscular nos grupos de idosos frente a perturbações da postura, especialmente dos músculos laterais, podem deixar esses indivíduos suscetíveis a quedas. Portanto, investigações e programas de treinamento/tratamento que visam treinar ou restabelecer o equilíbrio em idosos melhorando a ativação dos músculos laterais devem ser desenvolvidos.

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Il est connu que le mouvement volontaire entraîne une perturbation de la posture, qui nécessite d'être compensée par des mouvement contre-perturbateurs définis comme " ajustements posturaux ". Ce processus dynamique, qui se produit avant, pendant et après le mouvement focal, nécessite la mobilité de la chaîne posturale, avec un patron spécifique pour chaque tâche.L'objectif de cette thèse de doctorat a été d'explorer l'influence de la mobilité du rachis sur les composantes focale et posturale du transfert assis- debout, ou sit-to-stand (STS), qui est une tâche indispensable à l'autonomie fonctionnelle. Trois séries expérimentales ont évalué l'effet d'une restriction de mobilité de la colonne vertébrale sur les ajustements posturaux anticipateurs (APAs) et le mouvement focal de la tâche de STS réalisée à vitesse maximale. Des paramètres biomécaniques ont été calculés à partir des données fournies par un plateau de forces et un capteur de pression. La première série a évalué l'effet de la mobilité lombo-pelvienne au moyen de trois types de contentions lombaires, et a montré qu'une réduction du jeu articulaire de cette région était associée des APAs plus longs et plus amples, ainsi qu'à une augmentation de la durée du mouvement focal. La seconde série a mis en évidence les mêmes variations en explorant l'influence de la mobilité de la colonne cervicale au moyen de trois contentions cervicales. La dernière série s'est focalisée sur le rôle de l'augmentation de la tension musculaire le long du tronc, en utilisant un protocole spécifique de compression bimanuelle. Les résultats ont montré qu'une tension musculaire plus élevée induisait une augmentation de la durée des APAs mais sans variation de la durée du mouvement focal. L'ensemble de ces résultats suggèrent que la colonne cervicale et la colonne lombaire sont à la fois impliquées dans les composantes focale et posturale du STS, et que le maintien de leur mobilité peut favoriser l'autonomie fonctionnelle. En revanche, l'augmentation de la tension musculaire le long du tronc nécessite uniquement une réorganisation des ajustements posturaux pour maintenir le même niveau de performance. / It is well known that voluntary movements induce internal disturbances to posture, which need to be balanced by counter-pertubing movements defined as " postural adjustments ". This dynamic process, which occurs before, during, and after the focal movement, requires the mobility of the postural chain, with a specific pattern for each task. The aim of this PhD thesis was to explore the influence of spine mobility on the focal and postural components of the sit-to-stand (STS) task, which is instrumental for functional autonomy. Three series of experiments assessed the effect of spine mobility restriction on anticipatory postural adjustments (APAs) and focal movement (FM) of the STS task peformed at maximum velocity. Biomechanical parameters were calculated from force plate, and pressure sensor data. The first series assessed the effect of lumbo-pelvic mobility using three different lumbar contentions, and showed that restricted articular free play in this area was associated with longer and larger APAs, along with a higher duration of the focal movement. The second series of experiment showed the same variations when exploring the effect of cervical spine mobility using three different cervical contentions. The last series focused on the effect of increased muscular tension along the trunk, using a specific bimanual compressive load paradigm.The results showed that higher tension lead to longer APAs with no variation of FM duration. Taken together, these findings suggest that the lumbar and cervical spine are involved in both the focal and postural components of the STS task, and that preserving their articular free play might be useful to favour functionnal autonomy. In contrast, increased muscular tension along the trunk only require a reorganization of the APAs to keep the same level of task performance.