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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.
51

Computational optimal control modeling and smoothing for biomechanical systems /

Said, Munzir. January 2007 (has links)
Thesis (Ph.D.)--University of Western Australia, 2007.
52

The biomechanical analysis of swimming propulsion in the sprint front crawlstroke /

Schleihauf, Robert Earl. January 1984 (has links)
Thesis (Ed. D.)--Teachers College, Columbia University. / Typescript; issued also on microfilm. Sponsor: Joseph Higgins. Dissertation Committee: Bernard Gutin. Bibliography: leaves 161-163.
53

Estudo de um sistema para análise da marcha humana utilizando sensores de contato

Gomes, Ronaldo de Campos [UNESP] 11 1900 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-11Bitstream added on 2014-06-13T18:57:58Z : No. of bitstreams: 1 gomes_rc_me_guara.pdf: 1511256 bytes, checksum: bc0195957d9fb0f95ad69191935e7359 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi estudar um sistema desenvolvido com sensores piezelétricos e um software para estudos da marcha humana. Participaram 10 voluntários, (5 mulheres e 5 homens): idade média de 32,6 anos, estatura média de 170,1 cm e peso corporal médio de 67,6 kgf. Para essa avaliação, dois sensores foram acoplados em cada palmilha dos calçados, em locais previamente estabelecidos (retro-pé e ante-pé) funcionando isoladamente. Foi solicitado aos participantes que eles caminhassem no solo com uma velocidade confortável, escolhida por eles, enquanto os sensores faziam as capturas, e os dados eram armazenados e analisados pelo software, desenvolvido para este estudo. Não foi objetivo deste trabalho comparar as médias dos valores da medição entre os sexos. Os resultados experimentais obtidos são coerentes com os da literatura afim, concluindo, desse modo, que o sistema, apesar de necessitar de algumas melhorias, proporciona condições adequadas para aplicação clínica em estudos sobre parâmetros temporais sobre a marcha. / This work aimed to study a system developed with a piezoelectric sensor and a software for human gait studies. 10 subjects volunteered to participate in the validation study, classified according to gender (5 female and 5 male): mean age of 32,6 years old, mean height of 170,1 cm and mean body weight of 67,6 kgf. For this evaluation, two sensors were attached in each insole, in places previously established (hindfoot and forefoot) working separately. Then, the subjects were asked to walk in a comfortable self selected speed while the sensors captured and the data were stored and analyzed by software developed for this study. This study didn’t aim to compare the values of averages between genders. The experimental results are consistent with the ones found in concerning literature, so that the system promotes proper conditions to clinical applications in temporal parameters gait studies, although it needs some improvements.
54

Análise computadorizada das cargas e deformações na utilização do fixador externo linear monoplanar nas fraturas instáveis da tíbia similar a tíbia humana

Silva, Orotavo Lopes da [UNESP] 13 December 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:28:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-12-13Bitstream added on 2014-06-13T18:34:55Z : No. of bitstreams: 1 silva_ol_me_guara.pdf: 1738809 bytes, checksum: 238d52438edc344671acd1cf6f9a194a (MD5) / Universidade Estadual Paulista (UNESP) / Fixadores externos constituem um importante recurso dentro do arsenal terapêutico dos ortopedistas na reparação das fraturas. Estão disponíveis em diversos modelos e sistemas, sempre fixados ao osso do paciente e com suas estruturas de sustentação permanecendo externamente à pele. Dentro de suas inúmeras aplicações nos dias atuais, destacam-se no tratamento inicial das fraturas expostas, uma vez que conferem estabilidade ao osso fraturado deixando um mínimo de material de síntese interno, o que minimiza as infecções. Dessa forma, sua disposição espacial necessita se planejada e confeccionada rapidamente, uma vez que suas peças são disponibilizadas separadas, ficando o resultado final em sua grande parte na dependência da experiência do cirurgião ortopedista. Este projeto visa gerar conhecimentos a respeito da análise computadorizada da biomecânica do sistema osso-fixador, direcionando o uso dos fixadores externos a uma aplicação menos empírica e com maior previsibilidade de seu comportamento em função das cargas a que será submetido. / External fixation equipment is now an important part of the therapeutic arsenal of orthopedicians when setting and repairing fractures. They are available in various models and several systems, always fixed to the patient's skin. Among the innumerable ways that this equipment is used nowadays, the initial treatment of exposed fractures stands out since it provides stability to the fractured bone at the same time that it leaves a minimum of internal synthesis matter or material, thus minimizing infection. In this way, the equipment's spatial placement needs to be planned and it should be rapidly put together, since the different parts are available separately leaving the final result largely dependent on the orthopedic surgeon's experience. This project has as its goal the creation of knowledge in relation to the computarized analysis of the biomechanics of the bone setting system, moving the use of external fixation equipment towards a less empirical application and in the direction of a greater predictability of its behaviour in function of the loads to which it will be submitted.
55

Impaired reflex sensitivity cause and effect

Corden, Danuta Maria January 1989 (has links)
When a voluntarily contracting human muscle is stretched its surface reflex electromyographic response has both short-latency (M1) and long-latency (M2) components. The M1 component occurs at a latency compatible with monosynaptic reflex activation. The long-latency component results from stimulation of skin and other subcutaneous receptors. In the initial experiment, using the first dorsal interosseous muscle (FDI) of the hand, the reflex sensitivity in normal human subjects was studied by comparing the various components of the electromyographic response generated by briefly stretching the voluntarily contracting muscle in subjects of various ages. It was found that age-related changes occur in the reflex response of human subjects. Although it is already known that the reflex response in human muscle slows with age, the result of the experiment showed that the size of that reflex response becomes smaller. The evidence suggests an impaired reflex sensitivity in older people which could be reflected in other motor control systems within the body. A detailed investigation was then undertaken to discover the causes of this change. Although the reflex response (M1) was found to alter with age the M2 component did not. This would seem to rule out neuromuscular block (NMB). NMB as a cause of the change was investigated and was found not to occur in the paradigm employed in this investigation. Possible changes in the mechanical properties of muscles and joints were looked for in a series of experiments using an accelerometer. No changes large enough to account for the reflex impairment could be found. In a further series of experiments the effects of fatigue and the effects of training on the electrical response of the FDI were studied. In a final series of experiments the changes with age, in the effects of coffee upon blood pressure were investigated.
56

Robotic Augmentation Of Human Locomotion For High Speed Running

January 2014 (has links)
abstract: Human running requires extensive training and conditioning for an individual to maintain high speeds (greater than 10mph) for an extended duration of time. Studies have shown that running at peak speeds generates a high metabolic cost due to the use of large muscle groups in the legs associated with the human gait cycle. Applying supplemental external and internal forces to the human body during the gait cycle has been shown to decrease the metabolic cost for walking, allowing individuals to carry additional weight and walk further distances. Significant research has been conducted to reduce the metabolic cost of walking, however, there are few if any documented studies that focus specifically on reducing the metabolic cost associated with high speed running. Three mechanical systems were designed to work in concert with the human user to decrease metabolic cost and increase the range and speeds at which a human can run. The methods of design require a focus on mathematical modeling, simulations, and metabolic cost. Mathematical modeling and simulations are used to aid in the design process of robotic systems and metabolic testing is regarded as the final analysis process to determine the true effectiveness of robotic prototypes. Metabolic data, (VO2) is the volumetric consumption of oxygen, per minute, per unit mass (ml/min/kg). Metabolic testing consists of analyzing the oxygen consumption of a test subject while performing a task naturally and then comparing that data with analyzed oxygen consumption of the same task while using an assistive device. Three devices were designed and tested to augment high speed running. The first device, AirLegs V1, is a mostly aluminum exoskeleton with two pneumatic linear actuators connecting from the lower back directly to the user's thighs, allowing the device to induce a torque on the leg by pushing and pulling on the user's thigh during running. The device also makes use of two smaller pneumatic linear actuators which drive cables connecting to small lever arms at the back of the heel, inducing a torque at the ankles. Device two, AirLegs V2, is also pneumatically powered but is considered to be a soft suit version of the first device. It uses cables to interface the forces created by actuators located vertically on the user's back. These cables then connect to the back of the user's knees resulting in greater flexibility and range of motion of the legs. Device three, a Jet Pack, produces an external force against the user's torso to propel a user forward and upward making it easier to run. Third party testing, pilot demonstrations and timed trials have demonstrated that all three of the devices effectively reduce the metabolic cost of running below that of natural running with no device. / Dissertation/Thesis / Masters Thesis Engineering 2014
57

Alterações morfologicas dos seios frontal e esfenoidal e do espaço aereo faringeo apos cirurgia ortognatica para correção de pacientes classe II / Morphologic changes of the frontal and sphenoid sinuses at pharyngeal airway space after orthognathic surgery for class II correction

Prado, Felippe Bevilacqua, 1980- 02 June 2009 (has links)
Orientador: Paulo Henrique Ferreira Caria / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T11:55:50Z (GMT). No. of bitstreams: 1 Prado_FelippeBevilacqua_M.pdf: 928965 bytes, checksum: 7b8a3874dca04c49fac0489b248033a6 (MD5) Previous issue date: 2009 / Resumo: A cirurgia ortognática tem sido regularmente usada no tratamento das deformidades dentofaciais, porém, seus efeitos sobre os tecidos moles e duros adjacentes ainda não estão totalmente esclarecidos. O objetivo desse estudo é avaliar cefalometricamente as alterações morfológicas dos seios frontal e esfenoidal e do espaço aéreo faríngeo superior e inferior em indivíduos com maloclusão classe II, submetidos à cirurgia ortognática com avanço maxilomandibular. Foram avaliados 49 pacientes (98 telerradiografias laterais), nos períodos pré- operatório (01 semana antes da cirurgia) e pósoperatório (seis meses após a cirurgia). Foram realizadas as medidas lineares: Nasofaringe (TB-PhW1), Orofarínge (TU-PhW2), ENA-Me, N-Me e S-Go e as medidas angulares SNA, SNB e Gonial além das dimensões dos seios frontal e esfenoidal em cada telerradiografia lateral. Os resultados foram submetidos ao test t de Student para avaliar as diferenças entre os dois momentos operatórios. Todas as medidas mostraram replicabilidade excelente para o intraclass correlation coefficient (ICC) (ICC>0,9; p<0,0001). Houve aumento das medidas TB - PhW1 e TU - PhW2 e diminuição das dimensões dos seios frontal e esfenóide após a cirurgia ortognática (teste t, p<0.0001). A cirurgia ortognática com avanço maxilomandibular altera a morfologia do espaço aéreo faríngeo superior e inferior e dos seios frontal e esfenoidal em indivíduos com má oclusão classe II após seis meses de correção. / Abstract: Orthognathic surgery has been regularly used in the treatment of dentofacial deformities; however, their effects on adjacent structures are not completely clarified. The purpose of this study was to evaluate cephalometrically the morphologic alterations of the frontal and sphenoid sinuses and superior and inferior pharyngeal airway space in class II malocclusion patients, after maxillomandibular advancement. The study included 48 patients (96 lateral teleradiographs) analyzed in the preoperative (1 week before surgery) and postoperative (six months after surgery) periods. In each lateral teleradiography, the linear measurements made were TB-PhW1 (nasopharynx), TU-PhW2 (oropharynx), ANSMe, N-Me and S-Go, the angular measurements were SNA, SNB and gonial, and the dimensions of the frontal and sphenoid sinuses were determined. The results were submitted to Student's t-test to evaluate the differences between the two operative times. The intraclass correlation coefficient (ICC) showed excellent reproducibility (ICC>0.9; p<0.0001) for the measurements. There was an increase in the measurements TB - PhW1 and TU - PhW2 and decrease of the dimensions of the frontal and sphenoid sinuses after orthognathic surgery. In conclusion, the orthognathic surgery consisting of maxillomandibular advancement alters the morphology of the pharyngeal airway space, superior and inferior, and of the frontal and sphenoid sinuses in individuals with class II malocclusion after six months of correction. / Mestrado / Anatomia / Mestre em Biologia Buco-Dental
58

The Effects of Delayed Visual Feedback on Postural Dynamics

Boulet, Jason January 2010 (has links)
We report on experiments and modeling of the interactions between delayed visual feedback and postural control in human quiet stance. A heuristic model is derived based on physiological and psychophysical parameters. The level of agreement found between the data and the model was found to be very good for power spectral densities, probability density functions and mean-squared displacements (or Hurst exponents). The stochastic delayed differential model identifies critical time scales of postural corrections. We also investigate properties of the model such as stability, small delay approximations and the power spectral density. Lastly, we use nonlinear time series techniques to investigate the temporal structure of the experimental postural dynamics. We propose the first dynamical model of visually assisted posture control.
59

Plantar fasciitis: Biomechanics, atrophy and muscle energetics

Chang, Ryan 01 January 2010 (has links)
Purpose. The purpose of this dissertation was to determine the effects of chronic plantar fasciitis on intrinsic foot structures with respect to biomechanics, muscle atrophy and muscle energetics. This was accomplished in three parts. Methods. In Part I, a three-dimensional motion capture system with a synchronized force platform quantified multi-segment foot model kinematics and ground reaction forces associated with walking. Healthy individuals were compared to individuals with chronic plantar fasciitis feet. Typical kinematic variables, measures of coupling, phase and variability were examined in rearfoot, forefoot and hallux segments. In Part II, foot and leg magnetic resonance images were taken in subjects with unilateral plantar fasciitis so that within each subject, the healthy limb could be compared to the plantar fasciitis limb. Cross sectional areas (CSA) of the plantar intrinsic foot muscles (PIFM) and tibialis posterior muscle were computed from user-digitized images. In Part III, the metabolic demands of the PIFM were evaluated using phosphorous magnetic resonance spectroscopy at rest and after barefoot walking. Muscle pH and the ratio of inorganic phosphate to phosphocreatine (Pi/PCr) were compared in healthy and plantar fasciitis feet. Results. In comparison to healthy feet, plantar fasciitis feet exhibited significantly (p < 0.05): (1) greater rearfoot motion, (2) greater sagittal plane forefoot motion, (3) fewer rearfoot-forefoot frontal anti-phase movements, (4) reduced rearfoot-forefoot transverse coordinative variability, (5) greater first metatarsophalangeal (FMPJ) joint dorsiflexion, (6) greater FMPJ-medial longitudinal arch (MLA) coupling variability, and (7) decreased vertical ground reaction forces at propulsion. Also, plantar fasciitis feet had 5.2% smaller PIFM CSA at the forefoot compared to contralateral healthy feet. No CSA differences were seen in the rearfoot PIFM or at the tibialis posterior muscle. The PIFM of healthy and PF feet were not significantly different in resting intracellular levels of pH or Pi/PCr, and there were no significant differences in the increase of Pi/PCr from rest to post-walking. Conclusions. In Part I, it was concluded that plantar fasciitis feet exhibit kinematics which are consistent with theoretical causation of the plantar fasciitis injury, that is, the plantar fasciitis foot exhibits excessive motion. Fewer number of anti-phase movements exhibited by plantar fasciitis feet may be an indication of pathology. The ground reaction force results suggested a compensatory pain response. In Part II, it was concluded that atrophy of the forefoot PIFM may destabilize the medial longitudinal arch and prolong the healing process. Lastly in Part III, it was concluded that resting energetics were consistent with muscle free of systemic disease or neuromuscular pathology. The presence of plantar fasciitis did not elicit systematic asymmetries in the metabolic response in comparison to healthy feet. Clinical Relevance. These kinematic results provided some evidence to support the clinical assertion that excessive motion is related to plantar fasciitis. These results also support treatment modalities which clinicians currently use to reduce rearfoot eversion, flattening of the medial longitudinal arch and dorsiflexion of the FMPJ (e.g. foot orthoses, insoles, taping, rocker soles). When treating plantar fasciitis patients, clinicians should assess for PIFM and tibialis posterior muscle atrophy and prescribe targeted exercises when appropriate.
60

Mechanics and energetics of footfall patterns in running

Gruber, Allison H 01 January 2012 (has links)
The forefoot (FF) running pattern has been recently advocated to improve running economy and prevent overuse injuries compared to the rearfoot (RF) pattern. However, these claims have not been supported by empirical evidence. The purpose of this dissertation was to investigate the potential advantages of RF and FF patterns to improve running economy and reduce injury risk in 20 natural RF and 20 natural FF runners. The first study found that the RF group was more economical when performing the RF pattern at a slow, medium, and fast speed vs. FF running. Only running at the fast speed resulted in a difference in economy between footfall patterns in the FF group in which RF running was more economical. Therefore, there is no advantage of FF running for improving running economy. The results of the second study indicated that there was a weak to moderate relationship between Achilles tendon (AT) moment arm length and running with either RF or FF patterns. AT force was greater during FF running, which may increase the risk of developing tendon injury. The third study used a modeling approach to find that FF running resulted in greater elastic energy recoil in the gastrocnemius (GA) and the soleus (SO). However, greater mechanical work overall with FF running resulted in no difference in metabolic cost of the GA between footfall patterns but greater metabolic cost of the SO compared to RF running. The fourth study found that shock attenuation was greater during RF running compared to FF running. Greater shock attenuation during RF running was a result of an increased load imposed on the system. Decomposing the vertical ground reaction force in the frequency domain revealed that RF running may have a greater reliance on passive shock attenuation mechanism whereas the FF pattern may have a greater reliance on active shock attenuation mechanisms. These results suggest that previous speculation that the FF running pattern is more economical was not substantiated. It is likely that each footfall pattern exposes a runner to different types of injuries, rather than one footfall pattern being more injurious than another.

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