abstract: Across primates, molar-emergence age is strongly correlated to life-history variables, such as age-at-first-reproduction and longevity. This relationship allows for the reconstruction of life-history parameters in fossil primates. The mechanism responsible for modulating molar-emergence age is unknown, however. This dissertation uses a biomechanical model that accurately predicts the position of molars in adults to determine whether molar emergence is constrained by chewing biomechanics throughout ontogeny. A key aspect of chewing system configuration in adults is the position of molars: the distal-most molar is constrained to avoid tensile forces at the temporomandibular joint (TMJ). Using three-dimensional data from growth samples of 1258 skulls, representing 21 primate species, this research tested the hypothesis that the location and timing of molar emergence is constrained to avoid high and potentially dangerous tensile forces at the TMJ throughout growth. Results indicate that molars emerge in a predictable position to safeguard the TMJ during chewing. Factors related to the size of the buffer zone, a safety feature that creates greater stability at the TMJ during biting, account for a large portion of both ontogenetic and interspecific variation in the position of emergence. Furthermore, the rate at which space is made available in the jaws and the duration of jaw growth both determine the timing of molar emergence. Overall, this dissertation provides a mechanical and developmental model for explaining temporal and spatial variation in molar emergence and a framework for understanding how variation in the timing of molar emergence has evolved among primates. The findings suggest that life history is related to ages at molar emergence through its influence on the rate and duration of jaw growth. This dissertation provides support for the functionally integrated nature of craniofacial growth and has implications for the study of primate life history evolution and masticatory morphology in the fossil record. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2017

abstract: Multi-touch tablets and smart phones are now widely used in both workplace and consumer settings. Interacting with these devices requires hand and arm movements that are potentially complex and poorly understood. Experimental studies have revealed differences in performance that could potentially be associated with injury risk. However, underlying causes for performance differences are often difficult to identify. For example, many patterns of muscle activity can potentially result in similar behavioral output. Muscle activity is one factor contributing to forces in tissues that could contribute to injury. However, experimental measurements of muscle activity and force for humans are extremely challenging. Models of the musculoskeletal system can be used to make specific estimates of neuromuscular coordination and musculoskeletal forces. However, existing models cannot easily be used to describe complex, multi-finger gestures such as those used for multi-touch human computer interaction (HCI) tasks. We therefore seek to develop a dynamic musculoskeletal simulation capable of estimating internal musculoskeletal loading during multi-touch tasks involving multi digits of the hand, and use the simulation to better understand complex multi-touch and gestural movements, and potentially guide the design of technologies the reduce injury risk. To accomplish these, we focused on three specific tasks. First, we aimed at determining the optimal index finger muscle attachment points within the context of the established, validated OpenSim arm model using measured moment arm data taken from the literature. Second, we aimed at deriving moment arm values from experimentally-measured muscle attachments and using these values to determine muscle-tendon paths for both extrinsic and intrinsic muscles of middle, ring and little fingers. Finally, we aimed at exploring differences in hand muscle activation patterns during zooming and rotating tasks on the tablet computer in twelve subjects. Towards this end, our musculoskeletal hand model will help better address the neuromuscular coordination, safe gesture performance and internal loadings for multi-touch applications. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2014

Orientador: René Brenzikofer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação Física / Made available in DSpace on 2018-08-18T23:16:43Z (GMT). No. of bitstreams: 1 Russomanno_TiagoGuedes_D.pdf: 2397435 bytes, checksum: af29f0b3e2c1249b82bd1eb348d679ab (MD5) Previous issue date: 2011 / Resumo: O esporte de alto rendimento não se limita mais à relação entre o técnico e o atleta. A simples observação e percepção subjetiva do técnico e sua intervenção não é mais suficiente como referência para corrigir ou melhorar o nível de desempenho de um atleta. Sendo assim a utilização da tecnologia pode ajudar a melhorar a qualidade das informações referentes ao desempenho de um atleta. Sendo assim o objetivo principal deste trabalho concentra-se na utilização de métodos de avaliação em biomecânica e engenharia de computação, através da integração de diferentes metodologias e no desenvolvimento de métodos de análise de desempenho de atletas, em situações competitivas em três diferentes modalidades: handball, provas combinadas e salto com vara. No handebol foi abordado o problema do rastreamento automático de jogadores, no qual foi proposto e avaliado um detector Boosting em cascata treinado automaticamente, baseado em segmentação morfológica para rastreamento de jogadores de handebol. O método proposto foi capaz de detectar corretamente 84% dos jogadores quando testado no segundo tempo do mesmo jogo onde foi treinado e 74% quando testado em um jogo diferente. Mostrando-se uma ferramenta útil para o rastreamento em modalidades coletivas com perspectivas e possibilidades de ser utilizada em outras modalidades de quadra ou campo. Nas provas combinadas foi abordado um novo sistema de pontuação que avalia uniformemente o desempenho de atletas do decatlo e heptatlo o método apresentado utiliza uma função logaritmo espelhado normalizado que facilita a livre escolha do gradiente (velocidade de crescimento) de acordo com as necessidades da competição. O método é simples, interpretável, uniforme em todos os eventos e pode ser utilizado em diferentes provas combinadas. No salto com vara foi realizada uma análise individual com objetivo de descrever a biomecânica do salto com vara da melhor atleta brasileira e confrontar com as melhores atletas da modalidade focando na energia mecânica do salto com vara, avaliando variáveis cinemáticas e parâmetros energéticos utilizando um sistema de análise cinemática tridimensional. A altura máxima atingida pelo centro de massa da atleta mostrou correlação significativa com a energia Final total (r= 0,82, P<0,01). A energia muscular da atleta brasileira foi de 1,18 ± 0,87 J/kg, enquanto para as atletas durante a final do salto com vara feminino em Sydney foi de 5,74 ±1,63 J/kg. Apesar dos baixos valores de energia muscular a atleta apresenta altos valores de E_Initial e E_Final, com valores médios, respectivamente de 45,96 ± 0,82 J/kg e 47,14 ± 0,71 J/kg. Quando comparada com outras saltadoras com vara que figuram na elite da modalidade, a atleta brasileira é uma das mais velozes, com altos valores de E_Final e E_Initial, o que lhe confere resultados expressivos no circuito mundial e a coloca entre as 5 melhores atletas atuais na modalidade. Em todas as modalidades analisadas levou-se em consideração a especificidade de cada modalidade e as variáveis mais importantes para a avaliação do desempenho dos atletas tendo como foco principal a utilização de recursos computacionais para melhorar a análise do desempenho nessas modalidades / Abstract: The high performance sport is no longer limited to the relation between coach and athlete. Simple observation and subjective perception of the coach and his intervention is no longer sufficient as a reference to correct or improve the performance of an athlete. Therefore the use of technology can help to improve the quality of information about the performance of an athlete. The main objective of this work is the use of evaluation methods in biomechanics and computer engineering through the integration of different methodologies and the development of methods of performance analysis of athletes in competitive situations in three different sports: Handball, combined events and pole vault. In handball was approached the problem of automatic tracking of players, which was proposed and evaluated a detector Boosting cascade automatically trained, based on morphological segmentation for tracking handball players. The proposed method was able to correctly detect 84% of the players when tested in the second half of the same game where he was trained and 74% when tested in a different game. Proved to be a useful tool for tracking in a team sports with prospects and possibilities to be used in other types of court or field games. For combined events we developed a new scoring system that uniformly evaluates the performance of athletes in the decathlon and heptathlon. Our method uses a normalized mirrored-logarithmic function which facilitates the free choice of its gradient (growth speed) according to competition needs.The method is simple, interpretable and even in all events and can be used in different combined events. In the pole vault was made an individual analysis in order to describe the biomechanics of the best Brazilian pole vault athlete and to compare with the best athletes in the world focusing on the mechanical energy of the pole vault, evaluating kinematic variables and energy parameters using a three-dimensional kinematic analysis system. The maximum height reached by the athlete's center of mass showed significant correlation with the final total energy (r = 0.82, P <0.01). The Brazilian athlete's muscle power was 1.18 ± 0.87 J / kg, while for the athletes during the final of the women's pole vault in Sydney was 5.74 ± 1.63 J / kg. Despite the low values of the muscular energy, the athlete has high values of E_Initial and E_Final with mean values of respectively 45.96 ± 0.82 J / kg and 47.14 ± 0.71 J / kg. When compared with other pole vaulter appearing in the elite of the sport, the Brazilian athlete is one of the fastest, with high values of E_Final and E_Initial, which places it among the five best athletes in the sport today. In all modalities analyzed we took into account the specificity of each modality and the most important variables for evaluating the performance of athletes with the main focus the use of computing resources to improve the analysis of performance in these modalities / Doutorado / Biodinamica do Movimento Humano / Doutor em Educação Física

This dissertation focuses on the investigation and development of an effective prosthetic training and rehabilitation platform with the use of virtual reality to facilitate an effective process to return amputees to the highest level of independence and functioning possible. It has been reported that approximately 10 million people live with a limb loss worldwide, with around 30% being an upper-extremity amputee. The sudden loss of a hand or arm causes the loss of fine, coordinated movements, reduced joint range of motion (ROM), proprioceptive feedback and aesthetic appearance, all which can be improved with the use of a prosthesis and proper training. Current literature has shown prosthetic devices to provide limited function to users in a variety of areas including hand operation, functionality and usability, all which could be improved with proper rehabilitation and training. It has been exhibited that a large percentage of amputees abandon or reject prosthesis use mostly due to limited function and lack of training or knowledge of the device. It has been reported that untrained amputees will adjust their body in an awkward or compensatory body motion rather than repositioning a joint position while performing a task with a prosthetic device. This causes misuse and improper function that has been shown to lead to significant injuries. An effective prosthetic training and rehabilitation regime would be advantageous in returning the patient to the highest level of independence and functioning possible, with proper use of their prosthetic device. A successful training and rehabilitation program would allow an amputee to improve their ability to perform with optimal motion and use all prosthetic control capabilities. This dissertation describes the development of a stick figure model of the user’s motion in real-time and a character avatar animating the individualized optimal goal motions. The real-time model directly corresponds to the user’s motion, with the option to have the character avatar simultaneously animating an optimal goal motion for the user to follow. These were implemented into the Computer Assisted Rehabilitation Environment (CAREN) system (Motek Medical, Amsterdam, Netherlands) to provide real-time visual feedback to the users while performing specified training and rehabilitating tasks. A ten camera Vicon (Oxford, UK) optical motion captured system was used with the CAREN system capabilities to track body and upper extremity prosthetic segments during range of motion (ROM), activities of daily living (ADL), and return to duty (RTD) tasks, with and without the use of the virtual reality visual feedback. Data was collected on five able-bodied subjects and five subjects with a unilateral transradial amputation using their personal prosthetic device. Through investigation and development, a preferred and effective way to display the visualization of the real-time and optimal models were revealed. Testing the subjects with and without the virtual reality visualization, exhibited the effectiveness of providing visual feedback. Results showed subject’s to have improved positing, movement symmetry, joint range of motion, motivation, and overall an improved performance of the series of tasks tested. With the integration of the optimal model visualization, real-time visual feedback, and additional CAREN system capabilities, upper-extremity training and rehabilitation techniques were shown to enhance with the use of virtual reality, through improved task performance, and functional advances. The results of this dissertation introduce an alternative means for clinicians to consider for effectively rehabilitating and training upper-limb amputees. Findings of this dissertation sought to provide useful guidelines and recommendation to aid in the development of a small-scale adaptable option for rehabilitation practitioners and at home use. The techniques investigated in this study could also be applicable for lower-limb amputee, post-stroke, traumatic brain injury, poly-trauma, and other patients with physically limiting disabilities. The techniques investigated in this study are expected to aid in the development of training and rehabilitation procedures for a variety of patient populations, to enhance the effectiveness and assist in improving the overall quality of life of others.

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Transtibial amputees are at increased risk of contralateral hip and knee joint osteoarthritis, likely due to abnormal biomechanics. Biomechanical challenges exist for transtibial amputees in gait and cycling; particularly, asymmetry in ground/pedal reaction forces and joint kinetics is well documented and state-of-the-art passive and powered prostheses do not fully restore natural biomechanics. Elliptical training has not been studied as a potential exercise for rehabilitation, nor have any studies been published that compare joint kinematics and kinetics and ground/pedal reaction forces for the same group of transtibial amputees in gait, cycling, and elliptical training. The hypothesis was that hip and knee joint kinematics and kinetics and ground and pedal reaction forces would differ due to exercise (gait, cycling, elliptical) amputee status (amputated, control [non-amputated]), and leg (dominant [intact], non-dominant [amputated]). Ten unilateral transtibial amputees and ten control participants performed the three exercises while kinematic and kinetic data were collected. Hip and knee joint flexion angle, resultant forces, and resultant moments were calculated by inverse dynamics for the dominant and non-dominant legs of both participant groups. Joint biomechanics and measured ground/pedal reaction forces were then compared between exercises, between the dominant and non-dominant legs within each participant group, and across participant groups. Significant differences in hip and knee joint flexion angles and timing, compressive forces, extension-flexion (EF) and adduction-abduction (AddAbd) moments, and anterior-posterior (AP) and lateral-medial (LM) reaction forces were found. Particularly, transtibial amputees showed maximum knee flexion angle asymmetry as compared to controls in all three exercises. Maximum hip and knee compressive forces, EF moments, and AddAbd moments were lowest in cycling and highest in gait. Asymmetry in amputee midstance knee flexion and timing in v gait, coupled with low maximum EF moment for the non-dominant leg, suggests that amputees avoid contraction of the non-dominant quadriceps muscle. Knee flexion angle and EF moment asymmetry in elliptical training suggests that a similar phenomenon occurs. Asymmetry in AP and LM reaction forces in gait, but not other exercises, suggests that exercises that constrain kinematics reduce loading imbalances. The results suggest that cycling and elliptical training should be recommended to transtibial amputees for rehabilitation due to reduced hip and knee joint forces and moments. Elliptical training may be preferred over gait due to decreased joint loading and loading asymmetry, but some asymmetry and differences from control participants still exist. Non-weight bearing exercises such as cycling may be best at reducing overall joint loading and joint load asymmetry but do not eliminate all kinematic and temporal asymmetries. Current state-of-the-art prosthetic leg design is insufficient in restoring natural biomechanics not only in gait but also in cycling and elliptical training. Improved prosthesis kinematics that restore non-dominant knee flexion in amputees to normal levels could help reprogram quadriceps muscle patterns in gait and elliptical training and hip and knee joint biomechanical asymmetries. Further work in comparing contralateral and prosthesis ankle joint biomechanics would help to elucidate the relationship between prosthesis design and its impact on lower limb joint biomechanics.

abstract: This dissertation aimed to evaluate the effectiveness and drawbacks of promising fall prevention strategies in individuals with stroke by rigorously analyzing the biomechanics of laboratory falls and compensatory movements required to prevent a fall. Ankle-foot-orthoses (AFOs) and functional electrical stimulators (FESs) are commonly prescribed to treat foot drop. Despite well-established positive impacts of AFOs and FES devices on balance and gait, AFO and FES users fall at a high rate. In chapter 2 (as a preliminary study), solely mechanical impacts of a semi-rigid AFO on the compensatory stepping response of young healthy individuals following trip-like treadmill perturbations were evaluated. It was found that a semi-rigid AFO on the stepping leg diminished the propulsive impulse of the compensatory step which led to decreased trunk movement control, shorter step length, and reduced center of mass (COM) stability. These results highlight the critical role of plantarflexors in generating an effective compensatory stepping response. In chapter 3, the underlying biomechanical mechanisms leading to high fall risk in long-term AFO and FES users with chronic stroke were studied. It was found that AFO and FES users fall more than Non-users because they have a more impaired lower limb that is not fully addressed by AFO/FES, therefore leading to a more impaired compensatory stepping response characterized by increased inability to generate a compensatory step with paretic leg and decreased trunk movement control. An ideal future AFO that provides dorsiflexion assistance during the swing phase and plantarflexion assistance during the push-off phase of gait is suggested to enhance the compensatory stepping response and reduce more falls. In chapter 4, the effects of a single-session trip-specific training on the compensatory stepping response of individuals with stroke were evaluated. Trunk movement control was improved after a single session of training suggesting that this type of training is a viable option to enhance compensatory stepping response and reduce falls in individuals with stroke. Finally, a future powered AFO with plantarflexion assistance complemented by a trip-specific training program is suggested to enhance the compensatory stepping response and decrease falls in individuals with stroke. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2019

Femoroacetabular impingement syndrome (FAIS) is a disorder characterized by specific morphology of the femur and/or acetabulum, which may lead to hip pain during gait. Compared to individuals without pain, people with FAIS walk with more anterior pelvic tilt, and their pain may result from excessive anteriorly-directed hip joint forces. Previous approaches using musculoskeletal modelling to calculate joint forces, however, may inaccurately assume that each individual stands in an entirely neutral position when determining static joint angles. Consequently, information on parameters that affect joint forces (such as pelvic tilt) is lost in kinematic data used to estimate joint loading. To observe the effect of computationally altered pelvic tilt on joint forces, gait data of six healthy individuals were processed using Vicon and Visual3D. Each participant’s pelvic tilt was adjusted by ±5 degrees and ±10 degrees of tilt at all time points. Five analyses were performed per individual: no change in tilt, two posterior (positive) tilts, and two anterior (negative) tilts. The resulting data were imported into OpenSim to estimate forces from the femur onto the acetabulum in the anterior, superior, and medial directions. Data for each participant were normalized for gait cycle and body weight in MATLAB. Statistical parametric mapping software was used to determine if the differences in joint loads were significant. A more anterior pelvic tilt led to a reduction in anteriorly-directed joint forces, and an increase in the superior and medial directions. Based on these results, each individual’s pelvic tilt (obtained from their stationary kinematic data) was accounted for when modeling FAIS and healthy individuals. Using the same methods as above, the hip joint forces of 22 people with FAIS were compared to those of 22 healthy individuals as both groups walked at a prescribed speed. Although there were reductions in joint forces in both FAIS limbs compared to those of the control group, the differences were not significant, possibly due to the high variability of joint forces. Despite the significant effects of pelvic tilt on hip joint force, other underlying assumptions need to be addressed in musculoskeletal modeling software in order to compare different conditions, such as the use of the same generic model despite differences in sex and hip morphology. Future studies comparing pathological and healthy joint loads can inform researchers on gait alteration strategies and the design of assistive devices to manage the symptoms and onset of conditions such as FAIS. / 2022-05-15T00:00:00Z

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