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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Análise do exercício de agachamento utilizando o método de Kane /

Nogueira, Rodrigo Pereira. January 2011 (has links)
Orientador: José Elias Tomazini / Banca: José Geraldo Trani Brandão / Banca: Renato Rocha / Resumo: O sedentarismo é crescente na população mundial e com ele cresce a incidência das doenças crônicas degenerativas. Em contrapartida têm-se os exercícios físicos que são recomendados para a prevenção, tratamento e reabilitação dessas doenças. A musculação é um desses exercícios e sua prática cresce cada dia mais. Dentre todos os exercícios que podem ser realizados na musculação, está o agachamento, que é muito utilizado para fortalecer a musculatura dos membros inferiores, porém a execução errônea do mesmo pode acarretar lesões irreversíveis ao praticante. Atualmente são utilizados conceitos biomecânicos para estudar e compreender os esforços mecânicos acerca do agachamento visando a proteção do sistema musculoesquelético. A presente dissertação tem como objetivo aplicar o método de Kane a um modelo de corpo humano buscando analisar os torques articulares e as forças nos tendões musculares dos membros inferiores durante o exercício de agachamento. A instrumentação contou com modelo biomecânico bidimensional (2D) desenvolvido a partir do método de Kane, que consiste na análise do sistema multicorpo através de conceitos de velocidades, forças ativas e inércia generalizadas. Os resultados de pico de torque encontrados foram de 36,9 N.m no tornozelo, 51 N.m no joelho e 119,1 N.m no quadril. Os resultados de picos de força nos tendões musculares foram de 1290 N no gastrocnêmio, 723 N no quadríceps e 730 N nos isquiotibiais. O método se mostrou eficaz ao calcular os esforços mecânicos nas articulações de membros inferiores, porém são necessários mais estudos englobando um maior número de variáveis para completa elucidação do assunto. / Abstract: Physical inactivity is increasing in the world population and with it the incidence of chronic degenerative diseases grows. In contrast, there are the exercises that are recommended for the prevention, treatment and rehabilitation of these diseases. Strength training is one of these exercises and their practice grows every day. Among all the exercises can be performed, is the squat, which is widely used to strengthen the muscles of the lower limbs, however the erroneous execution can result in irreversible damage. Biomechanical concepts are currently used to study and understand the mechanical stress on the squat in order to protect the musculoskeletal system. This study aims to apply the Kane's method to a human body model seeking to analyze the joint torques and muscle forces in the tendons of the lower limbs during the squat. The instrumentation featured biomechanical model with two-dimensional (2D) developed from Kane's method, which consists of analysis of multibody systems using concepts of generalized speed, generalized active forces and generalized inertia. The results of peak torque were 36.9 N.m in the ankle, 51 N.m in the knee and 119.1 N.m in the hip. The results of peak strength in the muscle tendons were 1290 N in the gastrocnemius, 723 N in the quadriceps to 730 N in the hamstrings. The method was reliable to calculate the mechanical stress on the joints of the lower limbs, but more studies are needed covering a larger number of variables to complete elucidation of this subject. / Mestre
2

Análise do exercício de agachamento utilizando o método de Kane

Nogueira, Rodrigo Pereira [UNESP] 14 December 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-14Bitstream added on 2014-06-13T20:18:21Z : No. of bitstreams: 1 nogueira_rp_me_guara.pdf: 931314 bytes, checksum: 6d876c670577d2caa4189e93a9106a4f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O sedentarismo é crescente na população mundial e com ele cresce a incidência das doenças crônicas degenerativas. Em contrapartida têm-se os exercícios físicos que são recomendados para a prevenção, tratamento e reabilitação dessas doenças. A musculação é um desses exercícios e sua prática cresce cada dia mais. Dentre todos os exercícios que podem ser realizados na musculação, está o agachamento, que é muito utilizado para fortalecer a musculatura dos membros inferiores, porém a execução errônea do mesmo pode acarretar lesões irreversíveis ao praticante. Atualmente são utilizados conceitos biomecânicos para estudar e compreender os esforços mecânicos acerca do agachamento visando a proteção do sistema musculoesquelético. A presente dissertação tem como objetivo aplicar o método de Kane a um modelo de corpo humano buscando analisar os torques articulares e as forças nos tendões musculares dos membros inferiores durante o exercício de agachamento. A instrumentação contou com modelo biomecânico bidimensional (2D) desenvolvido a partir do método de Kane, que consiste na análise do sistema multicorpo através de conceitos de velocidades, forças ativas e inércia generalizadas. Os resultados de pico de torque encontrados foram de 36,9 N.m no tornozelo, 51 N.m no joelho e 119,1 N.m no quadril. Os resultados de picos de força nos tendões musculares foram de 1290 N no gastrocnêmio, 723 N no quadríceps e 730 N nos isquiotibiais. O método se mostrou eficaz ao calcular os esforços mecânicos nas articulações de membros inferiores, porém são necessários mais estudos englobando um maior número de variáveis para completa elucidação do assunto. / Physical inactivity is increasing in the world population and with it the incidence of chronic degenerative diseases grows. In contrast, there are the exercises that are recommended for the prevention, treatment and rehabilitation of these diseases. Strength training is one of these exercises and their practice grows every day. Among all the exercises can be performed, is the squat, which is widely used to strengthen the muscles of the lower limbs, however the erroneous execution can result in irreversible damage. Biomechanical concepts are currently used to study and understand the mechanical stress on the squat in order to protect the musculoskeletal system. This study aims to apply the Kane’s method to a human body model seeking to analyze the joint torques and muscle forces in the tendons of the lower limbs during the squat. The instrumentation featured biomechanical model with two-dimensional (2D) developed from Kane’s method, which consists of analysis of multibody systems using concepts of generalized speed, generalized active forces and generalized inertia. The results of peak torque were 36.9 N.m in the ankle, 51 N.m in the knee and 119.1 N.m in the hip. The results of peak strength in the muscle tendons were 1290 N in the gastrocnemius, 723 N in the quadriceps to 730 N in the hamstrings. The method was reliable to calculate the mechanical stress on the joints of the lower limbs, but more studies are needed covering a larger number of variables to complete elucidation of this subject.
3

An examination of age-related differences in lower extremity joint torques and strains in the proximal femur during gait

Anderson, Dennis Earl 16 April 2010 (has links)
Hip fractures are serious injuries that are associated with high rates of morbidity and mortality in older adults. While much of the increased risk of hip fracture with age can be explained by age-related decreases in bone mineral density, muscles and motor control are altered by aging as well. Muscles forces in vivo are thought to have a prophylactic effect that can reduce shear and bending in the femur. This is beneficial because bone is stronger in compression than in shear or tension, and shear plays an important role in fatiguing bone. Understanding how aging and muscular loads affect strains in the proximal femur could lead to improvements in clinical screening and preventative measures for hip fracture. <p> Three studies were performed to investigate age-related changes in neuromuscular function during gait and how these changes affect strains in the proximal femur. Study 1 examined age differences in peak lower extremity joint torques during walking with controlled speed and step length. Studies 2 and 3 applied muscle forces estimated during gait to finite element models of the femur. Study 2 examined age differences in femoral strains, and Study 3 examined the sensitivity of strains to individual muscle forces. <p> The results support the idea that older adults walk with reduced contributions from the ankle plantar flexors and increased contributions from the hip extensors. Interactions between age and speed indicate that older adults utilized a different neuromuscular strategy than young adults to vary the speed of their gait. No age differences were found for the largest magnitude strains in the proximal femur. However, young adults were able to apply larger loads to the femur without corresponding increases in femoral strains. Strains in the femoral neck were found to be sensitive to muscle forces, particularly hip abductor forces. Strains in the sub-trochanteric region tended to be larger than those in the femoral neck, and less sensitive to muscle forces. These results increase our understanding of neuromuscular changes that occur with age, and the effects of these changes on the femur. / Ph. D.
4

Requirements for effective collision detection on industrial serial manipulators

Schroeder, Kyle Anthony 16 October 2013 (has links)
Human-robot interaction (HRI) is the future of robotics. It is essential in the expanding markets, such as surgical, medical, and therapy robots. However, existing industrial systems can also benefit from safe and effective HRI. Many robots are now being fitted with joint torque sensors to enable effective human-robot collision detection. Many existing and off-the-shelf industrial robotic systems are not equipped with these sensors. This work presents and demonstrates a method for effective collision detection on a system with motor current feedback instead of joint torque sensors. The effectiveness of this system is also evaluated by simulating collisions with human hands and arms. Joint torques are estimated from the input motor currents. The joint friction and hysteresis losses are estimated for each joint of an SIA5D 7 Degree of Freedom (DOF) manipulator. The estimated joint torques are validated by comparing to joint torques predicted by the recursive application of Newton-Euler equations. During a pick and place motion, the estimation error in joint 2 is less than 10 Newton meters. Acceleration increased the estimation uncertainty resulting in estimation errors of 20 Newton meters over the entire workspace. When the manipulator makes contact with the environment or a human, the same technique can be used to estimate contact torques from motor current. Current-estimated contact torque is validated against the calculated torque due to a measured force. The error in contact force is less than 10 Newtons. Collision detection is demonstrated on the SIA5D using estimated joint torques. The effectiveness of the collision detection is explored through simulated collisions with the human hands and arms. Simulated collisions are performed both for a typical pick and place motion as well as trajectories that transverse the entire workspace. The simulated forces and pressures are compared to acceptable maximums for human hands and arms. During pick and place motions with vertical and lateral end effector motions at 10mm/s and 25mm/s, the maximum forces and pressures remained below acceptable levels. At and near singular configurations some collisions can be difficult to detect. Fortunately, these configurations are generally avoided for kinematic reasons. / text
5

Análise da propagação de incertezas no método de dinâmica inversa tridimensional para membro inferior durante a marcha em diferentes velocidades / Analysis of propagation of uncertainties in the inverse dynamics method three-dimensional lower limb during gait at different velocities

Franklin de Camargo Junior 24 September 2012 (has links)
O objetivo deste estudo foi investigar o efeito do erro na localização do centro de pressão (5 e 10 mm) nas incertezas de momentos articulares dos membros inferiores em diferentes velocidades de marcha (1,0, 1,5 e 2,0 m/s). Nossas hipóteses foram que: as incertezas absolutas de momento articular diminuam de distal para o proximal e da condição de maior para a de menor velocidade. Os momentos articulares de cinco adultos jovens saudáveis foram calculados pelo método bottom-up de dinâmica inversa 3D, na dependência do qual estimamos as incertezas propagadas. Os resultados indicaram que existe uma relação diretamente proporcional entre os erros do centro de pressão e as incertezas de momento articular. As incertezas absolutas nos picos de momento expressas no sistema de referência anatômico diminuíram de distal para proximal, confirmando nossa primeira hipótese, exceto para o momento de abdução. Da menor para a maior velocidade de marcha ocorreu um aumento da incerteza no momento (de até 0,04 Nm/kg), confirmando agora nossa segunda hipótese, exceto, mais uma vez, para abduções de joelho e quadril. E ainda, as incertezas relativas variaram dependendo do plano e articulação (entre 5 e 31%), sendo os momentos articulares de joelho os mais afetados / The aim of this study was to investigate the effect of errors in the location of the center of pressure (5 and 10 mm) on lower limb joint moment uncertainties at different gait velocities (1.0, 1.5, and 2.0 m/s). Our hypotheses were that the absolute joint moment uncertainties would be gradually reduced from distal to proximal joints and from higher to lower velocities. Joint moments of five healthy young adults were calculated by inverse dynamics using the bottom-up approach, depending on which estimate the uncertainty propagated. Results indicated that there is a linear relationship between errors in center of pressure and joint moment uncertainties. The absolute moment peak uncertainties expressed on the anatomic reference frames decreased from distal to proximal joints, confirming our first hypothesis, except for the abduction moments. There was an increase in moment uncertainty (up to 0.04 Nm/kg for the 10 mm error in the center of pressure) from the lower to higher gait velocity, confirming our second hypothesis, although, once again, not for hip or knee abduction. Finally, depending on the plane of movement and the joint, relative uncertainties experienced variation (between 5 and 31%), and the knee joint moments were the most affected
6

A USER-SPECIFIC APPROACH TO DEVELOP AN ADAPTIVE VR EXERGAME FOR INDIVIDUALS WITH SCI

Shanmugam Muruga Palaniappan (6858902) 15 August 2019 (has links)
<div> <div> <div> <p>Patients with Spinal Cord Injury (SCI) have limited time with supervised therapy in rehabilitation hospitals. This makes it imperative for them to continue regular therapy at home so they can maximize motor recovery especially for performing Activities of Daily Living (ADL). However, physical therapy can be tedious and frustrating leading to a lack of motivation. A novel upper extremity movement measurement tool was developed using a commercial VR system to rapidly and objectively measure an individual’s range of motion, velocity of movement on an individual gesture basis, and frequency of movements in a three-dimensional space. Further, an exergame with varied and customizable gameplay parameters was developed. Through the analysis of participant interaction with the exergame, we identified gameplay parameters that can be adjusted to affect the player’s perceived and physiological effort. We observed that VR has a significant motivational effect on range of motion of upper limbs in individuals with tetraplegia. The motion data and kernel density estimation is used to determine areas of comfort. Moreover, the system allowed calculation of joint torques through inverse kinematics and dynamics to serve as an analysis tool to gauge muscular effort. The system can provide an improved rehabilitation experience for persons with tetraplegia in home settings while allowing oversight by clinical therapists through analysis of mixed reality videos or it could be used as a supplement or alternative to conventional therapy. </p> </div> </div> </div>
7

Contrôle de la contraction musculaire volontaire après un traumatisme médullaire cervical : Etude de la réorganisation des activations musculaires et corticales / Control of voluntary muscle contraction after a spinal cord injury : neuro-biomechanical study of the reorganization of muscular and cortical activations

Cremoux, Sylvain 02 December 2013 (has links)
La réalisation d’une action motrice implique l’activation simultanée des muscles agonistes et antagonistes contrôlés par le système nerveux central. Un traumatisme médullaire détériore la moelle épinière, entrainant une déficience motrice et des modifications du contrôle des activations musculaires. Ce travail étudie la réorganisation des activations musculaires, des activations corticales et des interactions corticomusculaires (ICM) d’un groupe traumatisé médullaire cervical (SCI) et d’un groupe contrôle (AB) lors de flexions et d'extensions isométriques autour de l’articulation du coude. En extension, nos résultats ont mis en évidence une altération des capacités de force maximale chez les SCI, associée à une augmentation des activations musculaires, une activation corticale identique aux AB et une diminution de l’implication du M1 dans le contrôle des activations musculaires. En flexion, la force développée, les activations corticales et les ICM étaient similaires chez les SCI et AB, mais les activations antagonistes et la difficulté à inhiber la contraction étaient plus importantes chez les SCI. Pour l’ensemble des participants, les ICM en flexion étaient différentes selon la fonction des groupes musculaires. Ces résultats suggèrent une altération du contrôle cortical des mécanismes inhibiteurs spinaux de la contraction musculaire après un traumatisme médullaire mais indiquent que le cortex moteur reste fonctionnel pour contrôler un acte moteur malgré l’atrophie des muscles extenseurs. Ces résultats pourraient trouver des applications cliniques pour l’élaboration de neuroprothèses nécessitant un contrôle simultané de différents groupes musculaires. / The realization of a motor action involves simultaneous activation of both agonist and antagonist muscles controlled by the central nervous system. Following spinal cord injury, damage to the spinal cord causes both a loss of motor efficiency and changes in the control of muscle activations. In the present work, we studied the reorganization of muscle activations, cortical activations and corticomuscular interactions (ICM) in spinal cord injured (SCI) and able-bodied (AB) participants during voluntary isometric contractions in flexion and extension around the elbow joint. In extension, our results showed altered capacity of maximum force production in SCI participants, associated with increased muscle activations, similar cortical activation and decreased involvement of M1 in the control of muscle activations when compared to AB participants. In flexion, the force capacities, cortical activations and ICM were similar between SCI and AB participants, but the activation of antagonistic muscles and the difficulty to inhibit the contraction were greater in SCI participants. For all participants in flexion, ICM were different depending on the function of the muscle groups. Taken together, these results suggest an alteration of the cortical control of spinal inhibitory mechanisms following a spinal cord injury, but suggest that the motor cortex remain functional to control a motor act despite the atrophy of the extensor muscles. These results could find clinical applications for the development of neuroprotheses involving simultaneous control of different muscle groups.

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