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Identifying potential risk factors that affect slip-induced falls is key to developing effective interventions for reduction of injuries caused by these accidents. Existing epidemiological evidence suggests that localized muscle fatigue might be considered as an intrinsic risk factor that causes lack of balance control leading to falls. The literature on the relationship between localized muscular fatigue of the lower extremity and the gait parameters affecting slip severity is scarce. The purpose of the present study was to examine how lower extremity fatigue (quadriceps) alters gait parameters and increases slip severity. Sixteen healthy young participants were recruited to walk across an unexpected slippery floor in two different sessions (Fatigue and No fatigue). Kinematic and kinetic data were collected using a three-dimensional video analysis system and force plates during both sessions. The gait parameters important in assessing slip severity were compared for the two different sessions to evaluate the effects of fatigue. A repeated measure one-way analysis of variance (ANOVA) and multivariate analysis was employed to predict statistical significance. The results indicated a substantial increase in the heel contact velocity (HCV), required coefficient of friction (RCOF), slip distance II (SDII), peak average knee joint moment during slip recovery (kneemompeak), fall frequency and, a decrease in the transitional acceleration of the whole body COM (TA) in the fatigue session further indicating higher slip severity due to fatigue. In addition, a strong positive correlation was observed between RCOF and HCV, HCV and SDII, and, SDII and kneemompeak. These findings provide new insights into the relationship between localized muscular fatigue and slip initiation/recovery process. The present study concluded that localized muscular fatigue affects the gait parameters and increases slip severity and hence can be considered as a potential risk factor for slip-induced falls. / Master of Science

While amputee gait has been studied in great detail, the influence of prosthetic foot sagittal and coronal plane stiffness on amputee walking biomechanics is not well understood. In order to investigate the effects of sagittal and coronal plane foot stiffness on amputee walking, a framework for manipulating the stiffness of a prosthetic foot needs to be developed. The sagittal and coronal plane stiffness of a low profile carbon fiber prosthetic foot was manipulated through coupling with selective-laser-sintered prosthetic ankles. The carbon fiber foot provided an underlying non-linear stiffness profile while the ankle modified the overall stiffness of the ankle-foot combination. A design of experiments was performed to determine the effect of four prosthetic ankle dimensions (keel thickness, keel width, space between the ankle top and bottom faces, and the location of the pyramid connection) on ankle-foot sagittal and coronal plane stiffness. Ankles were manufactured using selective laser sintering and statically tested to determine stiffness. Two of the dimensions, space between the ankle top and bottom faces and the location of the pyramid connection, were found to have the largest influence on both sagittal and coronal plane stiffness. A third dimension, keel thickness, influenced only coronal plane stiffness. A number of prosthetic ankle-foot combinations were created that encompassed a range of sagittal and coronal plane stiffness levels that were lower than that of the low profile carbon fiber foot alone. To further test the effectiveness of the framework to manipulate sagittal and coronal plane stiffness, two ankle-foot combinations, one stiffer than the other in the sagittal and coronal planes, were used in a case study analyzing amputee walking biomechanics. Differences in stiffness were large enough to cause noticeable changes in amputee kinematics and kinetics during turning and straight-line walking. Future work will expand the range of ankle-foot stiffness levels that can be created using this framework. The framework will then be used to create ankle-foot combinations to investigate the effect of sagittal and coronal plane stiffness on gait mechanics in a large sample of unilateral transtibial amputees. / text

Submitted by Anelise Milech (anelisemilech@gmail.com) on 2017-02-14T12:41:09Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Victor Edgar Pitzer Neto.pdf: 1437419 bytes, checksum: 1ac59adfb4d6299a5aa8424d7c90ab0d (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-02-16T20:41:35Z (GMT) No. of bitstreams: 2 Victor Edgar Pitzer Neto.pdf: 1437419 bytes, checksum: 1ac59adfb4d6299a5aa8424d7c90ab0d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-02-16T20:42:51Z (GMT) No. of bitstreams: 2 Victor Edgar Pitzer Neto.pdf: 1437419 bytes, checksum: 1ac59adfb4d6299a5aa8424d7c90ab0d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-02-16T20:43:04Z (GMT). No. of bitstreams: 2 Victor Edgar Pitzer Neto.pdf: 1437419 bytes, checksum: 1ac59adfb4d6299a5aa8424d7c90ab0d (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2014-05-22 / Sem bolsa / Nos últimos anos a população idosa tem aumentado gradativamente, projeções mostram que é o grupo etário de crescimento mais rápido. Essa expansão da expectativa de vida está muitas vezes associado à iminuição da capacidade de andar e redução da estabilidade postural, que podem resultar em lesões frequentes. As alterações advindas com a idade afetam de forma negativa o equilíbrio e a marcha, devido à iminuição da força e da massa muscular. Idosos em geral adotam um padrão de marcha mais conservador, ou seja, andam mais devagar, com assos mais curtos, alterando parâmetros têmporo-espaciais, como omprimento e velocidade do passo. A atividade física (AF) pode minimizar as perdas ecorrentes do avançar da idade, o nível de atividade física e um fator influenciador na marcha dos idosos. A fim de entender os benefícios relacionados à atividade física na marcha dos idosos, esse trabalho tem o objetivo de analisar a cinemática da marcha de idosos ativos, insuficientemente ativos e inativos através de fotogrametria computadorizada. O Presente estudo é caracterizado por er quantitativo, exploratório, de delineameamento transversal, a amostra será de 60 dosos divididos em grupos de 20, quanto ao seu nível de atividade física. Foram inseridos no grupo de idosos ativos aqueles que praticavam 150 minutos ou mais de atividade física (AF) semanal e no grupo nsuficientemente ativo idosos ntre 10 e 149 minutos semanais de AF. Para seleção dos idosos que fizeram parte do grupo inativo utilizou-se uma estratégia de pareamento por vizinhança, gênero e idade, tendo como referência o grupo de idosos ativos. Assim como nos demais rupos, os idosos pertencentes ao grupo inativo foram caracterizados após aplicação do IPAQ domínio atividade física no lazer. / In recent years the elderly population has gradually increased, projections how that it is the fastest growing age group. This increase in life expectancy is often associated with decreased ability to walk and ecreased postural stability, which may result in frequent injuries. The hanges that come with age negatively affect balance and gait due to reduced strength and muscle mass. Elderly in general adopt a more conservative gait pattern, or move more slowly with shorter steps by hanging temporal and spatial parameters, such as length and velocity. Physical activity (PA) can minimize losses triggered by advanced age and the level of physical activity is an influential factor in older people’s gait. In order to recognize the benefits related to physical activity in elderly gait, this study aims to analyze the gait kinematics of active, insufficiently ctive and inactive seniors through computerized photogrammetry. The present tudy is characterized as quantitative, exploratory and a cross sectional layout, the sample will be 60 seniors divided into groups of 20 according to their level of physical activity. In the active seniors ups were the individuals who practiced 150 minutes or more of weekly physical activity (PA) and in the insufficiently active group between 10 and 149 minutes per week of physical activity. For the selection of seniors who participated in the inactive group a strategy of pairing by neighborhood, age and gender was used having as reference the group of active seniors. Like other groups, the elderly belonging to the inactive group were characterized after applying IPAQ leisure physical activity domain.