This thesis investigates the differential effects of muscle fatigue on center of pressure (COP) sway and associated central processes (attentional demands and sensory re-weighting) in older compared with young adults. More specifically, we first sought to determine whether the effect of muscle fatigue on unipedal stance was greater during a dual-task in older versus young adults, and second, to determine whether the effect of muscle fatigue on bipedal stance was greater in a condition with less reliable proprioceptive information in older versus young adults. Our main results show that with different muscle groups fatigued (ankle or hip) and postural tasks with varying difficulty (unipedal stance or bipedal stance on compliant surface), young adults increased their COP sway displacement and velocity with muscle fatigue, but not the associated attentional demands. When the central nervous system needed to increase the weight of the vestibular inputs due to sensory information being less reliable at the ankle joints from standing on a compliant surface (peripheral somatosensory information), COP sway displacement and velocity in young adults were greater with ankle muscle fatigue. We also found that healthy older adults were able to compensate for muscle fatigue just as well as young adults when visual information was available during a unipedal stance or when visual information was not available during a bipedal stance on a firm surface. However, when standing on a compliant surface, older adults showed a greater increase in COP sway displacement compared to young adults and increased attentional demands when visual information was not available during a bipedal stance. Our results suggest that healthy young and older adults are able to compensate for ankle muscle fatigue to limit postural control alterations during quiet standing under different conditions, and that the extent of postural control alterations largely depends on the tasks performed. The compensation strategies may be less efficient for older adults with less reliable proprioceptive information and without vision. Thus, a frailer group of older adults, with already reduced proprioception and/or reduced vision could possibly have more difficulty to efficiently use the same compensation strategies, and may be more at risk of falling when fatigued.

Falls are the leading cause of injuries among Canadians who are aged at 65 years and over. The assessment of dynamic stability has been proved as an effective method to identify fall-prone elderly individuals, which is essential to fall prevention. Tai Chi has been recommended as an effective exercise to prevent falls by the American Geriatric Society and British Geriatric Society. It is important to examine dynamic stability among Tai Chi practitioners and to explore the mechanisms of the effects of Tai Chi practice on fall prevention. This study examined the dynamic postural stability which is assessed by center of mass (COM) range of motion, COM - center of pressure (COP) separation, and temporospacial measures of gait during obstacle-walking in two groups: Tai Chi group and healthy controls. Fifteen participants in each group were asked to complete two walking conditions, level walking and 20cm-obstacle walking. Results showed that when compared with Tai Chi group, control group adopted a conservative crossing strategy with a significantly smaller crossing stride, higher heel clearance, and smaller pre horizontal distance to make obstacle crossing as safe as possible. This conservative strategy indicates the inability to cross obstacle casually and it may be associated with the decline in muscle strength and proprioception. It also showed that Tai Chi practitioners displayed a significantly larger COM range of motion in both anteroposterior (AP) and mediolateral (ML) direction (p<0.05) and a significantly larger COM-COP separation in ML direction (p <0.01), as compared with control group. The larger range of motion of COM and distance between COM and COP indicates that Tai Chi practitioners have a better ability to tolerate unsteadiness, which means if perturbation occurs, Tai Chi practitioners have a larger range to shift COM in the boundary of base of support.

Orientador: Roberto Vilarta / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Educação Fisica / Made available in DSpace on 2018-07-20T14:02:56Z (GMT). No. of bitstreams: 1 Munhoz_MonicaPeixoto_M.pdf: 2005017 bytes, checksum: 3252372363929f866e33b4b9f4ec5c80 (MD5) Previous issue date: 1995 / Resumo: O objetivo principal deste estudo é fazer uma análise tridimensional das adaptações posturais da coluna vertebral observadas nos indivíduos submetidos à sobrecarga progressiva unilateral, simulando a ação de sustentar uma criança. Para isto, nos propusemos a estudar dez indivíduos do sexo feminino, não sedentárias e que não apresentaram desvios posturais significativos que pudessem interferir nos resultados obtidos. Considerando o fato do dorso humano ser uma superfície no espaço tridimensional, optamos pela metodologia de reconstrução tridimensional à partir de fotos estereoscópicas que nos forneceu com precisão a localização no espaço euclidiano tridimensional de vinte pontos anatômicos marcados sobre os processos espinhosos da coluna vertebral. As sobrecargas aplicadas foram de 0, 4, 12 e 16 Kg. Para cada situação calculamos as projeções sagitais, as curvaturas 2D e 3D que foram analisadas na forma de gráficos. Os resultados apontam que diante do aumento algumas respostas posturais foram sendo acentuadas. Entre elas as mais marcantes são: o deslocamento posterior do tronco, a acentuação da curvatura torácica e escolíoses, quando presentes. Os resultados obtidos demonstraram que apesar das peculiaridades individuais que caracterizam as adaptações posturais em geral é possível observar tendências em comum. Confirma também a importância de estudos posturais de corpo inteiro e quantitativos. Acreditamos que este tipo de comprovação quantificada vem fundamentar com propriedade os estudos e trabalhos para prevenção e tratamentos de problemas posturais, um mal que cada vez mais se incorpora a vida do homem moderno / Abstract: The main objective of this study is to make a three-dimensional analysis of the posture adjustments of the spínal curvature observed in subjects under a unilateral progressive overload, simulating the action of holding a chíld. For this purpose, we have proposed to study ten female no-sedentary subjects, who didn't present any significative posture deviations wich could interfere in the final results. Considering the fact that the human back is a surface in a three-dimensional space, we have choosen the tridimensional reconstruction methodology from stereoscopic photograph register wich has provided with precision the localization in a three-dimensional euclidian space of twenty anatomic points marked on the spinous processes of the vertebra. The anatomic points were placed with the subject in static and erect position in the definitive place to be photographed. The overload were applied using puppets of 0, 4, 12 and 16 Kg. Before increasing the overload some posture reactions were being accentuated. The most remarkable were the following: posterior trunk dislocation, the accentuation of the thoracic curvature and the accentuation of the scoliotics desviations when avaluable. This shows that, in spite of the individual peculiarities that characterize the posture adjustments in general, it is possible to notice common tendencies. This kind of quantified evidence gives a sound base to the studies and the works for prevention and treatment of posture problems, a trouble that is more and more incorporated in the life of the contemporary man / Mestrado / Mestre em Educação Física

<p>Validerat; 20140613 (global_studentproject_submitter)</p>

Title: Analysis of postural reactions on excercise with symetrical load of upper limbs by centrifugal force Summary: The aim of this thesis is testing excercise equipment Marrko and its effects on human body. Its based on the similar principle as few of established excersice equipments on the market, that are generating load on body by vibration. Thesis is based as biomechanical study pursuing specification of postural system reactions on specific excercises. EMG, Qualisys and Kistler systems were used to observe specific parameters in human body kinetics and muscle activity. Key words: Qualisys, EMG, Kistler, postural reactions

Title: Analysis of postural reactions of excercise with a load of upper limbs by centrifugal force. Summary: The aim of the study is the kinematic analysis of selected body segments (C7, Th4, Th8, Th12, AC and SIPS) during performance with a special exercise tool Marrko Core®. Another goal is to confirm the existing knowledge in the field of kinesiology about the rotation of spinal segments. In addition, we aim to compare the selected exercises with each other and asses their suitability for application in the general population with back pain of various etiologies. The experiment was performed as a biomechanical study, where specific biomechanical parameters in human body kinetics and muscle activity were measured during performance of specific exercises. All measurements have been undertaken in laboratory BEZ UK FTVS. Systems Qualisys, Kistler and EMG Noraxon were used for measurements of chosen parameters in human body kinetics and muscle activity. Participants: Participants attended in this study (8 individuals- 4 women and 4 men) were all healthy individuals, 20-40 years old, without any limitation of mobility and pain free. They were all recreational athletes. Key words: EMG, Kistler, Qualisys, postural stabilizatio

Introducción: La agricultura es un sector importante a nivel mundial, y sobre todo en nuestro país, el ambiente de trabajo presenta diversos factores de riesgo, pero son los factores de riesgo mecánicos, los principales que causan los trastornos más frecuentes en este sector, los musculoesqueléticos. Por lo que es necesario describir estas variables en agricultores peruanos y demostrar su asociación para posteriormente realizar intervenciones ergonómicas. Objetivos: Determinar el nivel de riesgo postural y el dolor musculoesquelético en agricultores durante la cosecha de cítricos, y asociar ambas variables. Diseño: Estudio descriptivo, observacional, transversal y prospectivo. Lugar: Terrenos agrícolas del distrito de Huaral-Lima. Participantes: 33 agricultores cosechadores de mandarina. Métodos: REBA (Rapid Entire Body Assessment), método para evaluar el nivel de riesgo postural; y un cuestionario elaborado, para el dolor musculoesquelético. Resultados: Los resultados mostraron que para el grupo A, el tronco, cuello y piernas fueron afectados; y para el grupo B, los brazos, antebrazos y muñecas. El nivel de riesgo de los cosechadores de mandarina es alto, las actividades corte del fruto al nivel de la cadera-muslo y rodilla-pierna fueron las más riesgosas. El 91% de la población presentó dolor musculoesquelético, las zonas más afectadas fueron la columna lumbar (41.4%), el hombro/brazo (18.9%) y la muñeca/mano (11.3%). El 60.4% de las zonas dolorosas presentaron intensidad leve, el 35.8% intensidad moderada, y solo el 3.8% intensidad alta. Conclusiones: Hay asociación entre el nivel de riesgo postural y el dolor musculoesquelético presente en los agricultores cosechadores de mandarina, con una diferencia significativa p < 0.05, según la prueba estadística Chi2. Por lo que es necesario una pronta intervención ergonómica en este sector. Palabras claves: nivel de riesgo postural, dolor musculoesquelético, cosechadores de mandarina / --- Introduction: Agriculture is an important sector worldwide, and especially in our country, the work environment presents several risk factors, but are mechanical risk factors, the main that cause the most frequent disorders in this sector, the musculoskeletal. So is necessary to describe these variables in peruvian farmers and demonstrate their association for later make ergonomic interventions. Objectives: Determine the postural risk level and the musculoskeletal pain in farmers during citrus harvesting, and associate both variables. Design: Descriptive, observational, cross-sectional and prospective study. Place: Farmlands of HuaralLima district. Participants: 33 tangerine harvester farmers. Methods: REBA (Rapid Entire Body Assessment) method to assess the postural risk level; and a questionnaire developed for musculoskeletal pain. Results: The results showed that for group A, trunk, neck and legs were affected; and for group B, upper arms, lower arms and wrists. The risk level of tangerine harvesters is high, cut the fruit at the level of hip-thigh and knee-leg activities were the riskiest. 91% of the population suffered musculoskeletal pain, the areas most affected were the low back (41.4%), shoulder / arm (18.9%) and wrist / hand (11.3%). 60.4% of the painful areas presented mild intensity, el 35.8% moderate intensity, and only 3.8% high intensity. Conclusions: There is association between the postural risk level and present musculoeskeletal pain in tangerine harvester farmers, with a significant difference p<0.05, according Chi2 statistical test. So is necessary a prompt ergonomic intervention in this sector. Keywords: postural risk level, musculoskeletal pain, tangerine harvesters / Tesis

Orientador: Paula Fávaro Polastri Zago / Resumo: O objetivo do estudo foi investigar o efeito das tarefas visuais com diferentes demandas atencionais nos processos adaptativos do sistema de controle postural e no comportamento do olhar de adultos jovens frente à mudança abrupta da amplitude da sala móvel. Participaram do estudo quarenta e cinco adultos jovens (20,53 ± 2,04 anos). Foram mensurados o peso e a estatura corporal de todos os participantes. Ainda, os participantes realizaram o teste de Snellen para garantir acuidade visual normal entre todos os participantes. Em sequência, os participantes foram posicionados em pé sob uma plataforma de força (AMTI) dentro de uma “sala móvel”, utilizando o equipamento de rastreamento do olhar (ASL - H6) para calibração dos equipamentos. Os participantes foram divididos aleatoriamente em três grupos: 1-) Grupo Fixação (GFIX): no qual o participante permaneceu fixando o olhar em um alvo na parede frontal da sala; 2-) Grupo Movimentos Sacádicos Horizontais Imprevisíveis (GMSI): no qual os participantes realizaram movimentos sacádicos ora a direita e ora a esquerda a partir do centro da tela, envolvendo a incerteza de localização do alvo e 3-) Grupo Movimentos Sacádicos Horizontais Imprevisíveis com tarefa de Memória (GMSI-M), no qual os participantes realizaram a tarefa visual similar a do GMSI concomitante a uma tarefa de memorização de um número prédeterminado. Ao final de cada tentativa, o participante do GMSI-M deveria indicar quantas vezes este número apareceu. O alvo foi um cír... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to investigate the effect of visual tasks with different attentional demands on the adaptive processes of the postural control system and eyes behavior of young adults during the implicit knowledge of altered moving room amplitude. Forty-five young adults (20.53 ± 2.04 years) participated in the study. Weight and height of all participants were measure. In addition, participants performed the Snellen Test to ensure visual acuity between all participants. After, they were positioned on a force plate (AMTI) inside a “moving room” using the eye tracking (ASL - H6) for equipment calibration. Participants were randomly divided into three groups: 1-) Fixation Group (GFIX): participant remained fixed at a target on the front wall of the room; 2-) Unpredictable Horizontal Saccade Movements Group (GMSI): participants performed saccades movements to the right and to left from the center of the screen, involving the uncertainty of the target location and 3-) Unpredictable Horizontal Saccade Movements Group with Memory task (GMSI-M): participant performed the visual task similar of the GMSI concomitantly with a number memorization task of a predetermined number. At the end of each trial, participants of the GMSI-M should indicated how many times this number appeared. The target was a circle with 1.71 degrees in diameter or an “X”, white or black because of the stripes on the walls of the room. The room movement conditions were: in first trial, the room remained ... (Complete abstract click electronic access below) / Mestre

Bakgrund: Postural kontroll är en komplex process där flertalet faktorer inverkar, men är central för en individs alla dagliga aktiviteter. Nedsatt postural kontroll kan resultera till skador och begränsad rörelseförmåga. Adekvata fysioterapeutiska interventioner är i och med detta nödvändiga för att förbättra den posturala kontrollen. Ett sett att utföra detta skulle kunna vara träning med slutna ögon. Träning med slutna ögon syftar till reducera den visuella informationen och träna de övriga sensoriska systemen. Detta är en metod som inte är välstuderad idag. Syfte: Syftet med studien är att kartlägga den vetenskapliga litteraturen avseende effekterna av träning med slutna ögon och dess påverkan på balans. Metod: En litteraturstudie genomfördes för att kartlägga inom aktuellt område med hjälp av databaserna: Pubmed, Scopus och google scholar. Mesh-termer i kombination med fritextord nyttjades för att få fram relevanta artiklar. PEDRO-scale användes för att kvalitetsgranska de inkluderade artiklarna. Resultat: Totalt inkluderades åtta artiklar i denna litteraturstudie som studerade träning med slutna ögon och dess effekt på balans. Tre studier undersökte kategorin idrott och tre studier undersökte neurologisk problematik. En annan studie undersökte den äldre människan och den sista artikeln studerade människor med avsaknad av hörsel. Två av artiklarna i studien visade på signifikanta skillnader gentemot kontroll grupperna. De övriga sex studier påvisade en förbättring, men påvisade ingen skillnad i jämförelse med kontrollgrupp. Konklusion: I denna kartläggning finns det indikationer till att träning med slutna ögon skulle vara gynnsamt inom vissa områden. I nuläget visar det dock att träning utan visuell input inte har några större fördelar gentemot träning med öppna ögon. Vidare forskning behövs.

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