The biomechanics and muscle activity of forward and backward slope walking was investigated in humans to gain additional insight into neural control strategies. An adjustable instrumented ramped walkway was constructed and validated. Kinematic, ground reaction force, and muscle activity data were collected from nine subjects walking at three grades (0%, 15%, and 39%) for each of four conditions (forward upslope and downslope and backward upslope and downslope). The changes observed in the data were generally progressive from 0% to 15% to 39% grade. During forward downslope walking the joint moment pattern at the knee changed significantly, power absorption increased, and changes in the muscle activity patterns corresponded directly to changes in joint mechanics. During forward upslope walking, the hip joint moment pattern changed significantly, power generation increased, and changes in the muscle activity pattern were not directly related to changes in the joint moments at all joints. The muscle activity pattern data suggest that modifications to the level walking control strategies were necessary during slope walking. Backward slope walking was used to further explore these findings. Backward upslope and forward downslope kinematics and kinetics were similar, as were those from backward downslope and forward upslope walking. However, power generation increased during upslope walking tasks and power absorption increased during downslope walking tasks, and the changes in muscle firing patterns were more similar for these tasks than for those with similar kinetics. Increased power generation required compensatory muscle activity at adjacent joints that was not directly related to the moments at those joints; increased power absorption did not require such compensatory activity, and muscle activity was directly related to the joint moments. Overall, these data suggest that changes in the control strategy and/or modifications of the level walking control strategy are strongly influenced by the power demands of a task. The characterization of forward and backward slope walking presented here is novel and has important implications for many patient populations; knowledge of the task mechanics may be used to develop or improve physical therapy and rehabilitation exercise programs as well as the design of replacement and/or assistive devices.

Made available in DSpace on 2016-12-06T17:07:07Z (GMT). No. of bitstreams: 1 Alexandre Azevedo.pdf: 1554836 bytes, checksum: 44119494437e2ee610d59d403183e1da (MD5) Previous issue date: 2015-11-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / One of the possible mechanisms that explain the increased speed forward walking (FW) after the training backward walking (BW) in people with hemiplegia could be an increased recruitment of ankle muscles during task BW. The goal of this study is compare the muscle activation (dorsi-flexors and plantarflexors) and the range of motion of the ankle during the tasks of FW and BW in subjects with hemiparesis after stroke and healthy control subjects. The study included 12 subjects (65 ± 9 years) with chronic hemiparesis (60 ± 40 months post-stroke) and mild to moderate impairment of lower limb (LL) (FMLL 25.0 ± 4.7 points). For the control group participated in 6 healthy subjects (62.2 ± 4.6 years). The range of motion (ROM) passive isokinetic torque of the ankle at 30º / sec and corresponding EMG activity in plantarflexor muscles (PF) - Medial gastrocnemius (MG) and soleus (SOL) and dorsiflexion (DF) - Tibialis anterior (TA ) and peroneus longus (PL) was compared between the legs with ANOVA oneway. They assessed the EMG activity of the muscles and the kinematics of the ankle during the AF and AT separately in each gait sub-phase: first double support (1DS), simple support (SS), second double support (2DS) and balance sheet (BL). Data were analyzed by ANOVA, taking as factors the direction (FW and BW) and LL paretic (LLP), non-paretic (LLNP) and control (CTL). The CTL group presented DF ROM greater than the LLNP and the LLP. The PF was greater torque in relation to LLNP and LLP and LLNP was greater than in the LLP. The DF torque was lower in the LLP compared to CTL and LLNP. The spatiotemporal variables stride length, stride length and walking speed were higher in AF and higher in CTL compared to LLNP and LLP. 1DS in stages, SS and 2DS ankle ROM was higher in CTL that LLNP and LLP. In 2DS and BL CTL showed higher ROM in the BW that in FW, and 2DS in the LLNP and LLP ROM in FW was higher. The CTL group showed higher EMG activity of DF (TA and PL) and PF (MG and SOL) for all sub-phases, and only in the BL RMS of all analyzed muscles was higher in FW compared to BW. In general the CTL group had higher amplitudes and higher EMG activity that the LLP and LLNP at all stages of the march. In 2DS and BL ankle ROM was higher in the BW in the CTL group, but not in LLNP and LLP. The swing phase the EMG activity of DF and PF was higher in FW compared to FL. Future studies should evaluate whether the lower ROM identified in kinematics is related to an ankle muscle co-activation in this population. / Um dos possíveis mecanismos que explicaria o aumento da velocidade do andar para frente (AF) após o treinamento do andar para trás (AT) em pessoas com hemiparesia poderia ser um maior recrutamento da musculatura do tornozelo durante a tarefa de AT. Pretendeu-se com esta pesquisa comparar a ativação muscular de dorsi e plantiflexores e a amplitude de movimento do tornozelo durante as tarefas de AF e AT entre sujeitos com hemiparesia pós-AVE e indivíduos controle saudáveis. Participaram do estudo 12 indivíduos (65±9 anos) com hemiparesia crônica (60±40 meses pós-AVE) e comprometimento leve a moderado de membro inferior (MI) (FMMI 25,0±4,7 pontos). Para o grupo controle participaram 6 indivíduos saudáveis (62,2±4,6 anos). A amplitude de movimento (ADM) passiva, o torque isocinético do tornozelo a 30º/s e a atividade EMG correspondente na musculatura plantiflexora (PF) (Gastrocnêmio Medial (GM) e Solear (SOL)) e dorsiflexora (DF) (Tibial Anterior (TA) e Fibular Longo (FL)) foram comparados entre os MI com a ANOVA de uma via. Foram avaliadas a atividade EMG da musculatura e a cinemática do tornozelo durante o AF e o AT separadamente em cada subfase da marcha: primeiro duplo apoio (1DA), apoio simples (AS), segundo duplo apoio (2DA) e balanço (BL). Os dados foram analisados através da ANOVA de duas vias, tendo como fatores a direção (AF e AT) e o MI (parético (MIP), não parético (MINP) e controle (CTL)). O grupo CTL apresentou ADM de DF maior que o MINP e que o MIP. O torque de PF foi maior no CTL em relação ao MINP e ao MIP e no MINP foi maior que no MIP. O torque de DF foi menor no MIP em relação ao CTL e MINP. As variáveis espaço-temporais comprimento da passada, comprimento do passo e velocidade de marcha foram maiores no AF em relação ao AT e maiores no CTL comparativamente ao MINP e MIP. Nas fases 1DA, AS e 2DA a ADM do tornozelo foi maior nos CTL que MINP e MIP. No 2DA e BL os CTL apresentaram maior ADM no AT que no AF, sendo que no 2DA o MINP e MIP a ADM no AF foi maior. O grupo CTL apresentou maior atividade EMG dos DF (TA e FL) e PF (GM e SOL) durante todas as subfases, sendo que apenas no BL a RMS de todos os músculos analisados foi maior no AF comparativamente ao AT. No 2DA e no BL a ADM do tornozelo foi maior no AT no grupo CTL, mas não nos MINP e MIP. O grupo CTL apresentou maiores amplitudes e maior atividade EMG que o MIP e MINP em todas as fases da marcha. Na fase de balanço a atividade EMG dos DF e PF foi maior no AF comparativamente ao AT.

Made available in DSpace on 2016-12-06T17:07:20Z (GMT). No. of bitstreams: 1 Leticia Carneiro.pdf: 3734746 bytes, checksum: a0b78adbb08c5dd544e613943f5c3d68 (MD5) Previous issue date: 2009-04-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Walking backwards is part of many daily activities such as sitting in a chair and crossing the street, and is also present in sport activities. The aim of this study was to analyze the biomechanical and motor behavior characteristics of walking backwards and forwards of adults in water and on land. The sample was composed of 22 adult subjects (11 women and 11 men). Before the data collection the researchers carried out anthropometrical measurements and placed markers at some anatomical landmarks: lateral of the trunk, greater trochanter, the lateral knee epicondyle, the lateral malleolus and the fifth metatarsal head of the right lower limb. Data collection procedures were the same for both conditions, in water and land. The level of immersion in the water was set at the height of the subjects xiphoid process. The subjects perform 10 valid trials in each direction at a self-selected speed, over a 7,5m-walkway containing a force plate. The force plate provided data for the vertical ground reaction forces (VGRF). The trials in both directions were recorded in the sagittal plane with a digital video camera 60 Hz. To edit the images and digitize the anatomical points, the APAS software was used. These processes were accomplished to obtain the hip, knee and ankle joint angles and the relative phases. Walking speed was measured with a system composed of a synchronized electronic stopwatch and two photocell timing lights. An analysis of covariance was carried out which considered the four situations and the speed was included as a covariate. For the walking backwards on land it was observed that the values of the first force peak were greater than the values of the second force peak. In the water, the peak values were similar and there was a load reduction of approximately 68%. The displacement curves of the ankle, knee and hip joints were similar between both conditions and the main differences were observed for the ankle joint. There was smaller plantar flexion during the walking backwards in both environments and the range of movement was greater in the walking backwards in the water. In walking forwards in water, it was observed that there were greater knee and hip angles during the initial contact and during maximum flexion. The maximum hip extension was greater in the walking forwards on land and less in the walking backwards in water. The analyses of the relative phases showed that the main differences in the leg-thigh relationships were observed between the direction of walking, but there were no differences between the conditios. The curves of the relative phases of the walking forwards and of walking backwards were similar but they were reversed. The results of this study provided some scientific bases for health professionals who prescribe the walking training as a form of physical conditioning or as therapeutic exercises. The variations in the tasks and the environments are important strateges for the improvement of abilities. / A marcha para trás esta embutida em inúmeras atividades diárias como sentar-se em uma cadeira, atravessar uma rua movimentada e na prática de esportes coletivos. Assim, o propósito desse estudo foi analisar através de ferramentas biomecânicas o comportamento motor da marcha para frente e para trás de adultos no ambiente terrestre e aquático. A amostra foi composta por 22 indivíduos adultos (11 mulheres e 11 homens). Antes de iniciar os testes os pesquisadores realizaram as avaliações antropométicas e marcaram os pontos anatômicos: lateral do tronco, trocânter maior, epicôndilo lateral do joelho, maléolo lateral e quinto metatarso no membro inferior direito dos sujeitos. O procedimento da coleta de dados foi o mesmo para os dois ambientes, sendo que no ambiente aquático o nível de imersão foi no processo xifóide. Os sujeitos realizaram 10 passagens válidas nas duas direções de marcha, em velocidade auto-selecionada, sobre uma passarela 7,5m que apresentava no centro a plataforma de força. A plataforma forneceu dados da curva de força vertical de reação do solo (FVRS). O procedimento da caminhada em ambas as direções e ambientes foi registrado no plano sagital através de uma câmera filmadora digital com freqüência de 60 Hz. As imagens foram editadas e os pontos anatômicos digitalizados através do software APAS para obtenção dos ângulos articulares do quadril, joelho e tornozelo e para obtenção da fase relativa. A velocidade foi medida através de fotocélulas que estavam conectadas a um cronômetro. Para análise estatística foi utilizada a análise de co-variância (ANCOVA), para as quatro situações do estudo, tendo a velocidade como co-variável. Os resultados indicaram que na marcha para trás aconteceu um maior primeiro pico de força (PPF) no ambiente terrestre. No ambiente aquático, foram observadas semelhança entre os picos e redução dos valores da FVRS em ~68%. A morfologia das curvas de deslocamento articular do tornozelo, joelho e quadril foram semelhantes entre as condições, sendo que o tornozelo apresentou as maiores diferenças. A articulação do tornozelo teve menor plantiflexão na marcha para trás nos dois ambientes e maior amplitude de movimento (ADM) na marcha para trás na água. A articulação do joelho apresentou maiores valores angulares durante o contato inicial e maior máxima flexão na marcha para frente no ambiente aquático. O quadril mostrou maiores ângulos no contato inicial, maior máxima flexão e maior ADM na marcha para frente no ambiente aquático. Sendo que a máxima extensão do quadril foi maior na marcha para frente no solo e menor na marcha para trás na água. A análise da fase relativa revelou que as maiores diferenças na relação dos segmentos perna-coxa foram observadas entre as direções de marcha, havendo poucas diferenças entre os ambientes. As curvas da fase relativa foram semelhantes, mais invertidas entre a marcha para frente e para trás. Os resultados desta pesquisa proporcionaram maior embasamento científico para os profissionais da saúde que prescrevem o treinamento da marcha como exercício físico ou terapêutico, sendo que a variação da tarefa e do ambiente são recursos importantes na melhora das habilidades.

Made available in DSpace on 2016-12-06T17:07:19Z (GMT). No. of bitstreams: 1 Vanessa Herber.pdf: 2070207 bytes, checksum: 249e6056643655f931fa3aebf9693642 (MD5) Previous issue date: 2009-04-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The backward walking (BW) has been used in protocols for rehabilitation and training in individuals with stroke, however little is known about their characteristics in terms of kinematic variables and motor pattern. The literature describes that for the execution of BW it is necessary to combine hip extension with knee flexion, components that are compromised in this population. The aim of this study is to compare the spatial, temporal and angular variables between the BW and forward walking (FW) and between the lower limbs [affected (AF) and non affected (NA)] in the BW in individuals with hemiparesis following stroke. Participated in the study 10 adults (56.4±8.4 years) with chronic hemiparesis (30.6±25.1 months after the stroke onset), with lower limb motor score of 25±4.4 in the Fugl-Meyer Scale, and gait speed of 0,92±0.3 m/s. Reflexive markers were placed in the acromion, greater trochanter, lateral condyle of the knee and lateral malleolus, on both sides of lower limb. The subjects were instructed to walk at comfortable speed and five trials on each side of the sagital plane (right and left) were captured with a digital camcorder with a frequency of 30 Hz, in both tasks, FW and BW. The Kinematics variables analyzed were the stride length, duration and speed and stance phase duration, and angular variables of knee and kip. For statistical analyses the ANOVA 2X2 (2 directions BW and FW and 2 legs AF and NF lower limbs) was used. In addition, it was used contrasts with T Student test and Bonferroni correction. The angular variables were submitted to the ANCOVA, and the speed was the co-variable. The individuals with hemiparesis have shown a decreased stride length and speed (p=0,001 e p=0,001) and increased duration and percentage of support in the stride (p=0,001) in BW compared to FW. The NA lower limb remained longer in stance in both conditions (BW and FW). Both lower limbs have presented a decrease in maximum knee flexion (p=0,001 e p=0,005) and maximum hip extension (p=0,001 e p=0,001) in BW. In general, the differences in the hip kinematics between the FW and BW remained when the speed was used as a co-variable. Regarding the comparison between the lower limbs during the BW, the NA lower limb has shown increased angular values (p values between p=0,006 e p=0,009) except for the maximum knee extension, where the AF lower limb showed increased extension values, probably because of a hyperextension which is typical in this population. Qualitative analyses of the coordination has shown a different behavior between legs, with a preference to simultaneous movements between hip and knee in 8 of the 10 participants, and anterior inclination of the trunk during swing in the BW. The BW could be and appropriate way of treatment that could be added to conventional gait rehabilitation programs in individuals with hemiparesis. We suggest further investigation on the effects of a BW training on the intra joint coordination between hip and knee. / O andar para trás (AT) tem sido utilizado corno forma de treinamento locomotor em indivíduos com hemiparesia pós acidente vascular encefálico (AVE). No entanto pouco se sabe sobre as características cinemáticas do AT nesta população. A literatura descreve que na execução do AT é necessária a extensão do quadril combinada com a flexão do joelho, componentes que estão comprometidos nesta população. O objetivo deste estudo é comparar em indivíduos com hemiparesia as variáveis espaço-temporais e angulares entre o andar para frente (AF) e o AT e entre membros inferiores (MMII) no AT. Participaram do estudo 10 indivíduos (56.4±8.4 anos) com hemiparesia crônica (30.6±25,1 meses pós AVE). Os participantes apresentaram comprometimento motor de 25±4.4 pontos no Fugl-Meyer-MI velocidade de marcha de 0.92±0.3 m/s. Marcadores foram colocados no acrômio, trocânter maior do fêmur; côndilo lateral do joelho e maléolo lateral em ambos os lados. Os participantes foram filmados caminhando em uma velocidade confortável em cinco tentativas no plano sagital direito e cinco no esquerdo, nas tarefas do AF e AT. com uma câmera filmadora digital com freqüência de 60 Hz. As variáveis cinemáticas analisadas foram comprimento, duração e velocidade da passada e duração do apoio, além das variáveis angulares do joelho e quadril. Os dados foram submetidos a ANOVA 2X2 [2 direções e 2 lados - MI não afetado (naf) e MI afetado (af)] e posterior contrastes com teste t de Student com correção de Bonferroni. As variáveis angulares foram em seguida submetidas a ANCOVA utilizando-se a velocidade do andar como co-variável. Os indivíduos com hemiparesia apresentam redução do comprimento e velocidade da passada e aumento da duração e do percentual de apoio da passada (p=0,001 para todos) no AT comparativamente ao AF. O MInaf permaneceu mais tempo apoiado tanto no AT quanto no AF. Ambos os MMII apresentaram valores de máxima flexão de joelho (p=0,001 e p=0,005) e máxima extensão de quadril significativamente menor (p=0,001 para ambos) no AT. Em geral, as diferenças na cinemática do quadril entre AF e AT permanecem quando a velocidade é utilizada como co-variável. Com relação à comparação entre os MMII no AT, observou-se que o MInaf apresentou maiores valores angulares (valor de p entre p=0,006 e p=0,009), exceto para máxima extensão do joelho. onde o MIaf apresentou valores maiores dc extensão, isso devido a hiperextensão característica nesta população. A análise qualitativa da coordenação evidenciou um comportamento diferente entre MMII com uma preferência para movimentos simultâneos entre o quadril e joelho para 8/10 participantes assim como uma inclinação anterior do tronco durante o balanço no AT. O AT pode ser utilizado como recurso terapêutico apropriada para somar aos programas convencionais de reabilitação da marcha em indivíduos com hemiparesia. Sugere-se investigar o efeito do treinamento do AT sobre coordenação inter-articular entre quadril e joelho.