Team lifting is required in many workplaces, particularly where heavy and awkward lifts are prevalent. Despite the known risk factors associated with team lifting, it remains under researched, with almost no 4-person lifting studies. The purpose of this thesis was to investigate how members of a 4-person team coordinate their actions during a lifting task that involved an unexpected release from a single team member. It involved a novel approach to investigating the mechanisms associated with joint action and whether these mechanisms may alert the remaining lifters that a release is imminent, where the goal was to elicit an unexpected response from the group. Data collected for a previous team lifting study was used. Six groups of four male participants (n = 24) performed 30 lifts with a constructed 60 kg lifting apparatus designed to transition between a rectangular (2 x 4 ft or 61 x 122 cm) and a square (2 x 2 ft or 61 x 61 cm) configuration. A total of 8 trials (4 per configuration) were designated as “drop trials”. Vertical force at the hands and right-side electromyography (EMG) of the biceps brachii (BB), anterior deltoid (AD), upper trapezius (UT), and the lumbar erector spinae (LES) was collected for each participant. Means and standard deviation of vertical force was compared from the pre-drop phase for both drop and non-drop (lift) trials. No significant differences were found between drop and non-drop trials during the pre-drop phase. A comparison of time to peak force and time to peak muscle activity was performed for lifters adjacent to the release position. These times were compared against a 25 to 150 ms window to determine whether the muscle activity was considered reflexive or anticipatory to the dropped load. A small proportion of the peak muscle activity values were considered anticipatory (6 BB and 2 LES), suggesting that while it is possible for the dropper to disguise the release, perhaps joint action provides insight to the other lifters. The complex mechanisms that support joint action, their connection to biomechanics and their role in team lifting warrants further research in order to determine how large of a role they might play. / Thesis / Master of Science in Kinesiology

It is essential to understand natural fracture systems embedded in shale-gas reservoirs and the stress fields that influence how induced fractures form in targeted shale units. Multicomponent seismic technology and elastic seismic stratigraphy allow geologic formations to be better images through analysis of different S-wave modes as well as the P-wave mode. Significant amounts of energy produced by P-wave sources radiate through the Earth as downgoing SV-wave energy. A vertical-force source is an effective source for direct SV radiation and provides a pure shear-wave mode (SV-SV) that should reveal crucial information about geologic surfaces located in anisotropic media. SV-SV shear wave modes should carry important information about petrophysical characteristics of hydrocarbon systems that cannot be obtained using other elastic-wave modes. Regardless of the difficulties of extracting good-quality SV-SV signal, direct shear waves as well as direct P and converted S energy should be accounted for in 3C seismic studies. Acquisition of full-azimuth seismic data and sampling data at small intervals over long offsets are required for detailed anisotropy analysis. If 3C3D data can be acquired with improved signal-to-noise ratio, more uniform illumination of targets, increased lateral resolution, more accurate amplitude attributes, and better multiple attenuation, such data will have strong interest by the industry. The objectives of this research are: (1) determine the feasibility of extracting direct SV-SV common-mid-point sections from 3-C seismic surveys, (2) improve the exploration for stratigraphic traps by developing systematic relationship between petrophysical properties and combinations of P and S wave modes, (3) create compelling examples illustrating how hydrocarbon-bearing reservoirs in low-permeable rocks (particularly anisotropic shale formations) can be better characterized using different S-wave modes (P-SV, SV-SV) in addition to the conventional P-P modes, and (4) analyze P and S radiation patterns produced by a variety of seismic sources. The research done in this study has contributed to understanding the physics involved in direct-S radiation from vertical-force source stations. A U.S. Patent issued to the Board of Regents of the University of Texas System now protects the intellectual property the Exploration Geophysics Laboratory has developed related to S-wave generation by vertical-force sources. The University’s Office of Technology Commercialization is actively engaged in commercializing this new S-wave reflection seismic technology on behalf of the Board of Regents. / text

Made available in DSpace on 2016-12-06T17:07:11Z (GMT). No. of bitstreams: 1 Alexandre Pinho.pdf: 2648154 bytes, checksum: 89f3e208e24484e5c16db812840b299c (MD5) Previous issue date: 2005-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this work was to investigate the relation of the vertical component of the ground reaction forces and the plantar pressure distribution during standing position, acting under the forefoot and the rearfoot, using high heel shoes and high heel simulators (wooden blocks of different heights and angles of heel support). The subjects were 30 symptom-free volunteer women, with no apparent foot and leg pathologies, with body mass index (BMI) up to 30 (Pollock, 1993) who are used to wear high heel shoes at least once a week. To obtain the relations on the weight force application and the pressure distribution under the feet the subjects were positioned standing over two force plates AMTI (Massachusetts, EUA, 1991) at 60Hz, synchronized with a pair of pedar mobile insoles (pedar® novelgmbh © 2005) at 50Hz. The foot was divided in two areas and data was acquired in 10 seconds of self balanced position. Significant differences between the means of vertical force and plantar pressure were found related to the heights differences and angle differences (p< 0,001), at the wearing shoes situation and with the simulators. The results of force and pressure did not follow a linear relation but increased as the heel height support got higher in both situations. / Este trabalho visou investigar a aplicação da força peso relativo ao peso corporal em retropé através da componente vertical da força de reação do solo (Fz) e a distribuição de pressão plantar nas regiões do retropé e antepé, na posição estática, em apoio bipodal, através do uso de calçados de salto e simuladores de altura e de ângulo de apoio do calcâneo. Participaram deste estudo 30 mulheres voluntárias, sem histórico de patologias em membros inferiores nos últimos 12 meses, sem índices de massa corporal que indicassem padrões de obesidade, segundo Pollock, (1993) e habituadas a utilizar calçado de salto pelo menos uma vez por semana. Os indivíduos utilizando calçados variados e blocos simuladores se posicionaram sobre duas plataformas de força AMTI (Massachusetts, EUA, 1991) dispostas em série adquirindo dados a uma freqüência de 60 Hz de forma sincronizada a um sistema de medição de distribuição de pressão plantar através de palmilhas sensorizadas (pedar® novelgmbh © 2005) adquirindo a uma freqüência de 50 Hz pelo tempo de 10 segundos. Verificou-se para a variável força vertical (Fz) diferenças significativas entre as médias tanto em relação às alturas (p< 0,001), como entre os ângulos (p< 0,001), obtendo-se similarmente nas situações real e simulada, ao nível de significância de 5%, um padrão não linear de diminuição da força vertical (Fz) em retropé e da pressão plantar nesta mesma região à medida que a altura do apoio no calcâneo aumenta.

In this study, we examined how hill running affects the Achilles tendon, which is a common location for injuries in runners. Twenty females ran for 10 min on three randomly selected grades (-6%, 0%, +6%). Achilles tendon (AT) cross-sectional area (CSA) was imaged using Doppler ultrasound and peak vertical forces were analyzed using high-speed (240 Hz) videography. A metabolic cart and gas analyzer ensured a similar metabolic cost across grades. Data were analyzed using a forward selection regression. Results showed a decrease in AT CSA from pre-run to post-run (p = .0001). Peak vertical forces were different across grades (p = .0001) with the largest occurring during downhill running and smallest during uphill running. The results suggest that the Achilles tendon is affected by running and a decrease in CSA appears to be a normal response. The AT CSA does not differ between grade conditions when metabolic cost of running is matched, suggesting an adaptive effect of the AT. Coaches and athletes can use this knowledge to develop workout protocols that transition runners to downhill running and allow them to adapt to these greater forces.

La prévalence de l’arthrose féline augmente fortement avec l’âge atteignant plus de 80% des chats de plus de 11 ans. L'arthrose induit une douleur chronique s’exprimant par des changements de comportements et une diminution de la mobilité. Il n'existe aucun outil validé pour évaluer la douleur chronique associée à l’arthrose chez le chat. Conséquemment, aucun traitement ciblant cette douleur n’a pu être validé. Notre hypothèse de recherche est que la douleur arthrosique chez le chat induit des handicaps fonctionnels, des changements neurophysiologiques et un état d'hypersensibilité qu'il faut évaluer pour quantifier de manière fiable cette douleur et ses répercussions sur la qualité de vie de l'animal. Nos objectifs étaient 1) de développer des outils adaptés aux chats mesurant les handicaps fonctionnels grâce à des outils cinématiques, cinétiques et de suivi de l'activité motrice ; 2) de caractériser les changements fonctionnels et neurophysiologiques secondaires à la douleur arthrosique et de tester avec ces outils un traitement analgésique à base d'anti-inflammatoire non stéroïdien ; 3) de développer une technique adaptée aux chats pouvant caractériser la présence du phénomène de sensibilisation centrale à l'aide d'une évaluation de la sommation temporelle mécanique ; 4) de tester la possibilité de mesurer le métabolisme glucidique cérébral par tomographie d’émission par positrons comme marqueur des changements supraspinaux secondaires à la chronicisation de la douleur. Grâce au développement d’outils de mesure de douleur chronique objectifs, sensibles et répétables nous avons caractérisé la douleur chez les chats arthrosiques. Ils présentent des signes de boiterie quantifiée par une diminution de l’amplitude de l’articulation ou par une diminution de la force verticale d’appui au sol et une diminution de l’activité motrice quotidienne. Ces deux derniers outils ont permis de démontrer qu’un anti-inflammatoire non stéroïdien (le méloxicam) administré pendant quatre semaines réduit la douleur arthrosique. De plus, grâce au développement de tests sensoriels quantitatifs et à l'utilisation d'imagerie cérébrale fonctionnelle, nous avons démontré pour la première fois que la douleur arthrosique conduisait à des modifications du système nerveux central chez le chat. Particulièrement, les chats arthrosiques développent le phénomène de sensibilisation centrale mis en évidence par un seuil de retrait aux filament de von Frey diminué (mesure réflexe) mais aussi par une facilitation de la sommation temporelle mécanique (mesure tenant compte de la composante cognitive et émotionnelle de la douleur). L'augmentation du métabolisme cérébral dans le cortex somatosensoriel secondaire, le thalamus et la substance grise périaqueducale, souligne aussi l'importance des changements liés à la chronicisation de la douleur. Un traitement analgésique adapté à l’arthrose permettra d’améliorer la qualité de vie des chats atteints, offrira une option thérapeutique valide aux praticiens vétérinaires, et profitera aux propriétaires qui retrouveront un chat actif et sociable. La découverte de l'implication du phénomène de sensibilisation central combiné à l'investigation des changements cérébraux secondaires à la douleur chronique associée à l'arthrose par imagerie fonctionnelle ouvre de nouvelles avenues de recherche chez le chat (développement et/ou validation de traitements adaptés à l'état d'hypersensibilité) et les humains (potentiel modèle naturel de douleur chronique associée à l'arthrose). / Feline osteoarthritis prevalence increases with age, up to 80% in cats aged 11 years old and more. Osteoarthritis is associated with chronic pain expressing as altered behaviour and a decrease in mobility. Currently, there is no validated technique to evaluate osteoarthritis-associated chronic pain in cats. This situation leads to an absence of approved medication for the treatment of OA-associated chronic pain in cats. Our hypothesis states that osteoarthritis-associated pain in cats is expressed as physical disabilities, neurophysiologic changes, hypersensibility, which need to be assessed to quantify adequately this pain and its impact on quality of life. Our objectives were 1) to develop a cat adapted method to assess physical disabilities using kinematics, kinetics and motor activity evaluations; 2) to describe functional and neurophysiologic changes related to osteoarthritis-associated pain, and to test a non steroidal anti-inflammatory based analgesic treatment; 3) to develop a cat adapted method to detect central sensitisation using mechanical temporal summation; 4) to test the feasibility of measuring carbohydrate brain metabolism using positron emission tomography as a marker of supraspinal changes-associated with pain chronicity. Using objective chronic pain evaluation tools determined as sensitive and repeatable, we characterized feline osteoarthritis-associated pain. Cats afflicted with osteoarthritis presented lameness characterised by decreased joint amplitude, or decreased peak ground reaction vertical force, and decreased motor activity. Using the two latter tools, we demonstrated the efficacy of a non steroidal anti-inflammatory (meloxicam) to alleviate osteoarthritis-associated pain after four weeks of administration. Moreover, using quantitative sensory testing and brain functional imaging, we demonstrated for the first time, that osteoarthritis-associated pain in cats led to central nervous system changes. Specially, cats afflicted with osteoarthritis developed central sensitisation as indicated by a decreased von Frey withdrawal threshold (a reflex evaluation), and also by a facilitated mechanical temporal summation (an approach allowing to take into account affective and cognitive dimensions of pain). The increase of brain metabolism in the secondary somatosensory cortex, thalamus and periaqueductal grey matter also highlighted the importance of pain chronicity related changes. Using an analgesic treatment built to alleviate osteoarthritis-associated pain will improve cats quality of life, will help veterinarians, and will benefit owners who will retrieve an active and social cat. Demonstrating both the importance of central sensitisation and assessment of brain changes related to osteoarthritis-associated chronic pain using brain functional imaging opens new research opportunities in cats (development and/or validation of hypersensitivity related treatments), and humans (potential natural model of osteoarthritis-associated pain).