Dentre os fatores relacionados ao treinamento, a escolha do exercício representa um dos aspectos menos abordados na literatura especializada. Ainda que seja determinante para a implementação do treinamento, tendo em vista que se trata do vetor a partir dos quais as adaptações neuro-musculares irão ocorrer, pouco se tem estudado acerca de suas características biomecânicas. O presente estudo objetivou caracterizar as ações de músculos do membro inferior durante a execução do levantamento terra no estilo convencional (LT) e na sua variação com os joelhos estendidos (LTJE). No protocolo proposto as variáveis relativas a atividade muscular foram registradas através de sistema de aquisição EMG 1000 (Lynx Inc). Para cada um dos músculos analisados - bíceps femoral (BF), vasto lateral (VL), multifido lombar (ML), tibial anterior (TA) e gastrocnêmio medial (GM) - foram analisados parâmetros relativos ao nível de máxima ativação durante o movimento, ao padrão temporal de ativação e ao tempo de contração. Para o nível de máxima ativação durante o LT, o BF (1,001±0,247U.A), VL (1,283±0,339U.A), (1,127±0,427U.A), TA (1,040±0,188U.A), GM (1,0385±0,120U.A) apresentaram variações discretas e não significativas (p<0,05). quando comparados com o LTJE, onde o BF apresentou (0.986±0,285U.A), o VL (1,011±0,146U.A), ML (1,060±0,205U.A), TA (1,092±0,153U.A), GM (1,083±0,163U.A). Comportamento semelhante foi verificado para o tempo de contração. As ausências de diferenças significativas evidenciam que os dois movimentos não apresentam estruturas diferentes, pois o comportamento temporal, intensidade de ativação muscular e tempo de ativação são semelhantes, o que mostra efetividade na utilização destes como estratégia de implementação em programas de treinamento e de reabilitação física. / Among the factors related to the training, the exercise choice represents one of the aspects less boarded in specialized literature. Yet it is determinative for the training implementation and considering it attends the vector that from it the neuromuscular adaptations will occur, and its biomechanical characteristics have been little studied. The present study aimed at characterizing the actions of selected muscles of the inferior member during the execution of the deadlift in the conventional style (LT) and its variation with the extended knees (LTJE). In the proposed protocol the variants of EMG have been registered by the acquisition system EMG1000 (Lynx Inc). For each analized muscle – lateral hamstring (BF), lateral vastus (VL), multifidus lumbar (ML), anterior tibia (TA) and medial gastrocnemius (GM) – were analized parameters related to the maximum activation level during the movement, to activation time standard and to contraction time. For the maximum activation level during the LT, the BF (1,001±0,247U.A), VL (1,283±0,339U.A), (1,127±0,427U.A), TA (1,040±0,188U.A), GM (1,0385±0,120U.A) have been presented discrete variations without significant differences (p<0,05), when compared with the LTJE, where the BF presented (0.986±0,285U.A), the VL (1,011±0,146U.A), ML (1,060±0,205U.A), TA (1,092±0,153U.A), GM (1,083±0,163U.A). The same result was verified for the contraction time. The absence of significant differences makes evident that both movement didn’t present different structures, therefore the activation time standard, the maximum muscular activation and contraction time were equal, what it shows effectiveness in the use of these as strategy of implementation in programs of training and physical rehabilitation.

Silk fibroin from silkworm cocoons is found in numerous applications ranging from textiles to medical implants. Its recent adoption as a biomaterial is due to the material's strength, biocompatibility, self-assembling behavior, programmable degradability, optical clarity, and its ability to be functionalized with antibodies and proteins. In the field of bioengineering it has been utilized as a tissue scaffolding, drug delivery system, biosensor, and implantable electrode. This work suggests a new application for porous silk in a microscale chromatography column. We demonstrate in situ cryotropic polymerization of highly porous structures in microscale geometries by freezing aqueous silk with a solvent. The resulting cryogels are experimentally characterized using flow parameters common in chromatography design; tortuosity, global pressure drop, pore diameter, and porosity. These empirical parameters are put into porous flow models to calculate an order-of-magnitude increase in functional surface area over the blank capillaries and packed-sphere columns used in traditional designs. Additionally, the pressure requirements to produce relevant flow rates in these structures are found not to threaten the integrity of microfluidic seals or connectors.

La Radio/Hadron-thérapie consiste à déposer une dose létale de rayonnement dans la tumeur tout en réduisant l'impact de cette dose sur les tissus sains. Les mouvements internes, en particulier ceux engendrés par la respiration modifient la forme, la position et la densité des organes, source d'erreur et d'incertitude sur la position du dépôt de dose. Lorsque la tumeur se trouve sur un organe en mouvement, la dificulté majeure est de cibler la tumeur pendant le traitement. Cette incertitude sur la position rend indispensable la mise en place d'une stratégie permettant la prédiction du mouvement tumoral. Ceci permet en eet de guider le faisceau de rayons ionisants de sorte qu'il suive les mouvements tumoraux. De plus, le traitement par hadronthérapie nécessite également l'accès à une description précise de la densité de l'ensemble des organes traversés par le faisceau, car la position du dépôt maximal de l'énergie véhiculée par les ions (le pic de Bragg) en dépend. Malheureusement, le mouvement respiratoire est complexe et sa prédiction n'est pas une tâche simple – en particulier, la respiration est commandée par l'action indépendante des muscles de la cage thoracique et du diaphragme. Les techniques actuelles basées sur l'imagerie, telles que le Cone-Beam ou le recalage dé- formable d'images, tentent de prédire la position des tumeurs pulmonaires. Ces méthodes font l'hypothèse d'un mouvement reproductible de l'appareil respiratoire dans le temps. D'autres techniques basées sur l'emploi de deux caméras à rayons X (cyberknife, tracking mis au point par l'équipe du Centre carbone d'Heildelberg [HIT]) peuvent permettre la pré- diction de la position des tumeurs, quand leur segmentation et leur contourage automatique en temps réel est possible. Cependant, ces méthodes sont, si ce n'est risquées, invasives, et elles ne permettent pas de calculer l'évolution des organes environnants, une information indispensable pour déterminer la position du pic de Bragg. Ainsi déduire le mouvement de la tumeur à partir de seules séries d'images médicales apparaît comme insuffisant. Une solution peut alors résider dans le développement d'un modèle biomécanique patient-spécifique du système respiratoire intégrant la variabilité du mouvement respiratoire. Pour que ce modèle soit précis, il doit comprendre la modélisation de la cage thoracique, du diaphragme et des poumons. Il est tout aussi important que ce modèle puisse être piloté par des paramètres mesurés en externe (capteurs 3D, spiromètre, etc.) an de préserver un caractère non-invasif et de corréler le mouvement externe du thorax et de l'abdomen, ainsi que le ux d'air échangé avec les mouvements internes. Les changements de propriétés mécaniques des milieux traversés par le faisceau doivent également être modélisés an de satisfaire les besoins de l'hadronthérapie. / The 4D computational patient specic of the respiratory system could be potentially used in various medical contexts; for diagnosis, treatment planning, laparoscopic, dose computation or the registration between online imaging systems such as positron emission tomography (PET), computed-tomography (CT) as well as high delity and precise computer-based training simulators. The main novelty of this PhD project lies in the context of radiation therapy; we have developed a patient-specic biomechanical model of the respiratory system enabling the correlation of the internal organs motion with respiratory surrogate signal(s) during the treatment. This permits to take into account the respiratory motion variabilities. The deformation of the dierent structures is controlled and driven by simulated rib cage (mimic the external intercostal muscles) and diaphragm actions. For the diaphragm, we have applied the radial direction of muscle forces, and simple homogeneous dirichlet boundary condition is applied to the lower part of the diaphragm, which is attached to the rib cage. For each rib a rigid transformation is calculated automatically by nite helical axis method (rigid translation and rotation) and used to dene displacement boundary conditions. The resulting widening of the thoracic cavity forces the lungs to expand due to an applied negative pressure in the pleural cavity. Other novelty of the PhD project, that the amplitude of the lung pressure and diaphragm force are patient-specic, and determined at dierent respiratory states by an optimization framework based on inverse FE analysis methodology, by minimizing the volume lungs errors, between the respiratory volume (calculated from CT scan images at each state) and the simulated volume (calculated by biomechanical simulation). All other structures are linked to each other, but feature dierent deformation behavior due to the assigned material properties. Our results are quite realistic compared to the 4D CT scan images and the proposed physically-based FE model is able to predict correctly the respiratory motion

With aging there is a decrease in a person’s ability to perform activities of daily living (ADL) which may be most effectively addressed using training patterns that are biomechanically similar to ADL. Since aquatic exercise offers the opportunity to provide resistance with a high level of safety, the pool may afford the ideal environment for ADL-specific training in an aging population. Purpose: The purpose of this investigation was to compare a traditional aquatic exercise program (TRAD) to an aquatic program tailored to target ADL (ADLspec). Methods: Eighteen independently living individuals (68.7 + 7.5 years) were randomly assigned to a TRAD or ADLspec aquatic exercise group. The exercise groups attended 1 hr exercise sessions, 2 times per week for 8 weeks. ADL ability was assessed using the short version of the Continuous-Scale Physical Functional Performance Test (PFP-10); while strength and power were assessed using the 30s arm curl and 30 sec. chair stand tests. Results: Mixed design ANOVAs revealed a significant group x time interaction for floor sweep time with the ADLspec group outperforming the TRAD and control (CON) groups (p = .043). Additionally, the ADLspec group improved the pan weight and scarf time components of the PFP-10 (p < .020), while the TRAD group improved pan time and laundry time (p < .046). Both training groups showed similar improvements for jacket time, grocery weight, and 6-min walk, (p < .046). The ADLspec and TRAD groups also made similar improvements in upper and lower body strength, as well as lower body power across time, (p < .043). A student’s t-test revealed the TRAD group spent more time exercising during the hour session than the ADLspec group (p < .05). Conclusion: The results indicate that performing an ADLspec aquatic exercise program can increase performance of ADL that require more complex sequential movements; however, ADL more dependent on fitness may be better addressed using a TRAD intervention. These results can be helpful when designing a periodized aquatic training program to increase independence in older persons.

Elevated intraocular pressure (IOP) is one of the major risk factors for glaucoma. Since glaucoma is a leading cause of blindness, reliable methods for measuring the IOP are important. This doctoral dissertation presents a new method, applanation resonance tonometry (ART), for measurement of IOP. The method is based on resonance sensor technology combined with the novel multipoint analysis of continuously sampled data of both contact force and contact area. The ART was evaluated in in vitro porcine-eye studies as well as in clinic on both healthy volunteers and patients. A new symmetric probe with a larger sensor tip and improved aligning light was developed and evaluated in vitro. It showed that the error from off-centring was highly reduced. The new ART probe, used as a biomicroscope device (ARTBiom) and as a handheld device (ARTHand), was further evaluated in a clinical study designed in accordance with the International Standard Organisation’s (ISO) requirement. Both the ARTBiom and the ARTHand met the precision set by the requirements. Laser surgery is a common way to correct vision. The biomechanical effect of photorefractive keratectomy (PRK) on IOP measurements was evaluated using Goldmann applanation tonometry (GAT) and ART in an in vitro study. Both methods were affected, but to a different extent. The flat contact probe of GAT, as compared with the convex tip of ART, and single point vs. multipoint approach, provide explanation to the ART advantage regarding measurement error of IOP after PRK. In conclusion, resonance sensor technology has made it possible to introduce a new multipoint method for measuring IOP, and the method is relevant for measuring IOP in humans. It may be possible to reduce errors in the clinical measurement of IOP with this new method, especially after corneal surgery. The ART has the potential to become a useful clinical instrument for IOP measurement.

Pigs, mice and human beings are all vertebrate mammals. More than 90% of genomes in pigs and mice are the same as human beings. Experiment pigs and mice are with advantages in purebloods, small size, high reproductive capacity and short life cycle, etc. The tissue structure and metabolism of physiology in pig and mice are similar to human as well. Therefore, laboratory pigs and mice are often used to substitute human beings for biomedical engineering test. The research topics of this thesis are in the area of biomechanical properties of bones in mammal. The objectives of the study are to reveal the biomechanical properties of various types of bones and discuss its implication to human development. The entire thesis is divided into three parts. The first topic used micro-indentation test and FEM analysis for the determination of biomechanical properties of controlled cartilages in pigs. The second topic applied (a) three-point-bend failure test to study the age-related radius strength in mice, (b) tensile test to study the mechanical response of cranial sutures in mice, and (c) optical interferometry for 3D profile determination of mouse cranium. The third topic is for quantitative analysis of patterns in cranial sutures using DFT (Discrete Fourier Transform). The mechanism of diseases (such as osteoporosis, craniosynostosis, etc.) and the complexity of patterns in human cranial sutures in different age groups are discussed.

Aims: The primary physiotherapeutic aims of the study were to validate a manual physiotherapy evaluation technique in the assessment of cervical biomechanical dysfunction, and to test the effectiveness of a manual physiotherapy treatment technique in the correction of cervical biomechanical dysfunction. The primary educational aims were to test the effectiveness and safety of a therapeutic exercise programme for the correction of biomechanical dysfunction as well as the effectiveness of a neck rehabilitation programme for improving neck muscle strength. Design: A four group experimental design with three pre-test - post-test groups and a control group was used for the investigation. Sample: The subjects were South African schoolboy rugby players between the ages of 15 and 18 years. Groups I and 2 presented with biomechanical dysfunction of their cervical spines, Group 3 had no biomechanical dysfunction of their cervical spines and the players of Group 4, the control group, presented with or without biomechanical dysfunction of their cervical spines. Each group consisted of 25 players. Method: Group I received manual physiotherapy with x-rays before and after treatment. Groups 2 and 3 performed a therapeutic exercise programme, with before and after x-rays, and Group 4 received no intervention between their sets of x-rays. Following the second set of x-rays all the players from Groups I, 2 and 3 performed the neck rehabilitation programme after which a third set of x-rays were taken. Results: The results validated the manual physiotherapy evaluation technique. The manual therapy treatment technique used in the treatment of Group I showed highly significant improvements in cervical biomechanical function. Results for Group 2 following the therapeutic exercise programme showed moderate practically significant improvements in cervical biomechanical dysfunction. The therapeutic exercise programme for the correction of biomechanical dysfunction was found to be very safe with only small significant changes in x-ray measurements (Group 3). The results of the control group showed a negative trend of small statistical significance. A highly significant improvement in cervical circumference as moderate significant improvement in biomechanical function was found following the neck rehabilitation programme. Conclusion: It could therefore be concluded that the manual physiotherapy evaluation technique for motion segment analysis was indeed valid in determining biomechanical dysfunction of the cervical spine. The manual physiotherapy treatment technique as well as the therapeutic exercise programme for the correction of biomechanical dysfunction was found to be effective in the correction of cervical biomechanical dysfunction. It could further be concluded that the therapeutic exercise programme was safe to be performed by players without biomechanical dysfunction. The neck rehabilitation programme was effective in improving cervical circumference as well as cervical biomechanical function. / Thesis (Ph.D. (Education))--North-West University, Potchefstroom Campus, 2005.

We describe a semi-automatic technique for modeling and animating complex musculoskeletal systems using a strand based muscle model. Using our interactive tools, we are able to generate the motion of tendons and muscles under the skin of a traditionally animated character. This is achieved by integrating the traditional animation pipeline with a biomechanical simulator capable of dynamic simulation with complex routing constraints on muscles and tendons. We integrate our musculoskeletal modeling and animation toolkit into a professional 3D production environment, thereby enabling artists and scientists to create complex musculoskeletal systems that were previously inaccessible to them. We demonstrate the applications of our tools to the visual effects industry with several animations of the human hand and applications to the biomechanics community with a novel model of the human shoulder.

This thesis includes the development, construction and testing of internal organ phantoms, with focus on the liver, for biomechanical testing. Phantoms have various biomedical applications such as surgical simulations, minimally invasive surgery, soft tissue characterization, diagnostic tools and instrumentation calibration. However, there is little work present in literature regarding phantoms and the work that is currently available does not account for the non-linear viscoelastic properties as well as the Glisson’s capsule. In this work, three different phantoms are presented: a fluid-filled phantom, a perfused phantom and a hydrogel-based liver phantom. A testing apparatus is designed, built and used to measure the force-displacement data during the indentation of the phantom. The first phantom that is designed and constructed follows the basis of a fluid-filled vessel. It is composed of a linear low-density polyethylene (LLDPE) bag filled with different fluids namely: water, a 1:1 water/glycerine mixture and glycerine. The phantoms are subjected to quasi-static loading as well as relaxation testing. The effect of density and viscosity, its size, and confined and unconfined boundary conditions are characterized. The second phantom is designed to investigate the effects of hepatic macrocirculation on the biomechanical properties of the liver. The phantom is made of two-part silicone (Smooth-On, ECOFLEX 00-30), and contains a network of conduits to model the large ! iv! blood vessels in the liver. A perfusion system that captures the general features of the human hepatic circulation is used to help investigate the effects of the different flow parameters such as pressure and flow rate on the biomechanical characteristics of the liver. The perfusion system is designed to reproduce comparable pressures to the human portal vein and hepatic artery. The third phantom is made of two parts, a hydrogel inner layer with a LLDPE outer layer. The idea behind this phantom is to represent the organ as accurately as possible by accounting for the capsule that surrounds the organ as well as the biphasic (solid and fluid) nature of the organ. A biphasic poroviscoelastic model is used to model the hydrogel while the LLDPE uses a non-linear hyperelastic and viscoelastic model. Modeling is done in ABAQUS to fit the experimental data obtained from quasi-static indentation and relaxation testing using a parametric study. In conclusion, phantoms replicating the non-linear viscoelastic properties observed in organs are presented and characterized. Main Thesis Contributions • Development and characterization of a simple fluid-filled phantom to represent the mechanical properties of the liver • Development and characterization of hydrogel-based liver phantom with representation of the biphasic nature of the organ and the Glisson’s capsule. ! v! • Development and characterization of perfused liver phantom with ability to be recreated with various vessel configurations. • Development of testing set-up to characterize various phantoms.

Biomedical image processing is a very important research area. Image analysis is one of the most important techniques in studies related to heart functions. The clinical assessment of LV function is very important to evaluate the heart function for patients or suspected heart disease sufferers. 2D echocardiography allows us to study the dynamic analysis of the heart which results in obtaining the quantitative and qualitative analysis of the LV. Cardiac function quantitative analysis depends on the heart’s shape characteristics like the enclosed area and heart wall thickness. The segmentation of medical images and obtaining the traces of the LV boundaries is an essential procedure to get the quantitative and qualitative analysis. Yet, in clinical procedure, this task depends on manual tracing which is slow, tedious and time consuming job. Hence, automating this clinical procedure during the cardiac cycle is of great importance. The aim of this thesis is to automate the manual process of detecting and tracking the LV boundaries of 2D echocardiographic image sequence. Instead of depending only on the imaging based techniques, the designed and implemented framework utilizes the LV mechanics beside the imaging based techniques. When it comes to information extraction from patterns which have been classified, it has been proved that the different contour detection methods complement each other. As a result, efficient combination of different contour detectors is expected to achieve better contour detection than if only one detector is used. This combination of contour detectors produces incremental gains in overall performance. In the first framework, the detection and tracking are accomplished by employing the extended Kalman filter framework to combine the contours estimated by the biomechanical model and the contours extracted using the deformable models. An alternative framework is used by employing averaging fusion followed by level set method. A gold standard is created from three manual outlines and utilized in the experimental results to evaluate the automated results. The tracking and segmentation of LV during the cardiac cycle was accomplished successfully in all cases. The results showed limits of agreement for an average perpendicular distance of 1.277 ±0.252 mm versus the created gold standard. This proved that this framework achieved better performance in tracking and segmenting the LV through the cardiac cycle.