Human locomotor economy and efficiency are highly variable. This study investigated the role that stature plays in this variation, by evaluating metabolic and respiratory responses to walking and running at speeds set relative to one's stature. Four groups of subjects: male, high V0₂ max (n = 11); male, average V0₂ max (n = 10); female, high V0₂ max (n = 10); and female, average V0₂ max (n = 11) were habituated to treadmill locomotion prior to the measurement of maximal oxygen consumption (V0₂ max). The V0₂ max test entailed 1 km.h⁻¹ increases per min from 3 to 6 km.h⁻¹ walking, and 7 - 17 km.h⁻¹ running then 1% grade increments per min until exhaustion. On each of four other occasions, the subject walked or ran at 6 of a variety of relative speeds - walking at 0.5, 0.7, 0.9, 1.1, 1.3; running at 1.5, 1.7, 1.9 and for selected subjects 2.1, 2.3 and 2.5 statures.s⁻¹ ,and grades - 0%, +3%, -3%. Steady-state respiratory and metabolic responses, and treadmill speed were monitored by an on-line computer system developed for this study. Cadence and RPE were also monitored. All subjects demonstrated an exponential relationship between V0₂ and walking relative speed (st.s⁻¹) (RS) . V0₂ (ml.kg⁻¹.min⁻¹ ) = 4.747 * e(1.371*RS) During running this relationship was essentially linear . The variability of economy at relative speed (9.08%) and absolute speed (9. 01%) did not differ. Male and female subjects did not differ in response to absolute speed but females were more economical at relative speeds (p<0.05). Those with high and average aerobic capacity did not differ in locomotor economy at relative speed. Higher freely-chosen stride length was associated with a higher V0₂ response as velocity increased. The V0₂ of uphill walking was 1.4 times greater than that for downhill walking (running: 1.28 times) . Stride length decreased with increasing speed in uphill locomotion but the reverse was the case for downhill. The economy and efficiency of walking was greater than that of running. Walking economy was maximal between 0.7 and 0.9 st. s⁻¹. Running economy remained essentially unaffected by increased velocity. The setting of locomotor velocity relative to stature does not minimize inter-subject variability in metabolic and respiratory response .

L’appareillage permet à aux personnes amputées de membre inférieur de retrouver une autonomie de déplacement. Actuellement, cette autonomie est limitée dans certaines situations de la vie courante comme la marche en pente ou en escalier. Des capteurs dits embarqués sont de plus en plus souvent intégrés dans les prothèses et permettent d’enregistrer des informations cinématiques et dynamiques au cours de la locomotion. Dans ce contexte, l’objectif de la thèse est de contribuer au développement de méthodes de traitement des données issues de ces technologies pour quantifier et améliorer l’adaptation de la prothèse à l’environnement. Ces méthodes ont été mises en œuvre et évaluées dans le cadre de l’utilisation d’un nouveau système prothétique contrôlé par microprocesseur de genou-cheville (SPCM), développé par la société Proteor et visant à faciliter la locomotion des personnes amputées au-dessus du genou dans les situations de pente ou de descente d’escalier. La première partie de cette thèse a été consacrée à la quantification des adaptations permises par le SPCM au cours de la locomotion dans différentes situations de la vie courante (plat, pente, escalier). La deuxième partie de la thèse s’est intéressée à développer des estimations de paramètres de la marche (vitesse de marche et inclinaison de la pente) et à la classification de 4 situations de la vie courante (plat, montée et descente de pente, descente d’escalier) à l’aide d’algorithmes d’apprentissage automatique pouvant être calculé par le SPCM en temps réel. L’ensemble de ces travaux permettra de mieux quantifier l’activité réelle de l’utilisateur. Cette quantification pourrait aider l’utilisateur ou l’équipe médicale pour le suivi d’activité mais aussi le constructeur pour améliorer l’adaptation des éléments prothétiques à l’environnement rencontré et pour vérifier l’utilisation réelle du SPCM. / Prosthetic devices allow people with lower limb amputation to recover their autonomy. Currently, this autonomy is limited in several everyday life situations such as walking on a slope or in stairs. Embedded sensors, frequently integrated inside the prostheses, record kinematic and dynamic data during locomotion. In this context, this PhD thesis aims to contribute to the development of methods for the processing of data provided by these technologies to quantify and improve the adaptation of the prosthesis to the environment. These methods were applied and evaluated in the context of the use of a new prosthetic knee-ankle system controlled by microprocessor (SPCM) developed by Proteor to facilitate the locomotion in situations such as slope or downstairs walking for people with above knee amputation. The first part of the work was devoted to the quantification of the adaptations allowed by the SPCM in different situations of daily life (flat, slope, staircase). The second part of the thesis focused on the estimation of gait parameters (walking speed and slope inclination) and the classification of 4 everyday life situations (flat, slope ascent and descent, stair descent) using machine learning algorithms that can be computed by the SPCM in real time. The body of this work will make it possible to better quantify the user real life activity. This quantification could help the user or the medical team in the activity monitoring but also the manufacturer to improve the adaptation of the prosthetic components to the environment and to verify the SPCM actual use.

abstract: Spinal cord injury (SCI) disrupts the communication between supraspinal circuits and spinal circuits distal to the injury. This disruption causes changes in the motor abilities of the affected individual, but it can also be used as an opportunity to study motor control in the absence or limited presence of control from the brain. In the case of incomplete paraplegia, locomotion is impaired and often results in increased incidence of foot drag and decreased postural stability after injury. The overall goal of this work is to understand how changes in kinematics of movement and neural control of muscles effect locomotor coordination following SCI. Toward this end, we examined musculoskeletal parameters and kinematics of gait in rats with and without incomplete SCI (iSCI) and used an empirically developed computational model to test related hypotheses. The first study tested the hypothesis that iSCI causes a decrease in locomotor and joint angle movement complexity. A rat model was used to measure musculoskeletal properties and gait kinematics following mild iSCI. The data indicated joint-specific changes in kinematics in the absence of measurable muscle atrophy, particularly at the ankle as a result of the injury. Kinematic changes manifested as a decrease in complexity of ankle motion as indicated by measures of permutation entropy. In the second study, a new 2-dimensional computational model of the rat ankle combining forward and inverse dynamics was developed using the previously collected data. This model was used to test the hypothesis that altered coordination of flexor and extensor muscles (specifically alteration in burst shape and timing) acting at the ankle joint could be responsible for increases in incidence of foot drag following injury. Simulation results suggest a time course for changes in neural control following injury that begins with foot drag and decreased delay between antagonistic muscle activations. Following this, beneficial adaptations in muscle activation profile and ankle kinematics counteract the decreased delay to allow foot swing. In both studies, small changes in neural control caused large changes in behavior, particularly at the ankle. Future work will further examine the role of neural control of hindlimb in rat locomotion following iSCI. / Dissertation/Thesis / Ph.D. Bioengineering 2012

No description available.

Orientador: José Angelo Barela / Resumo: O objetivo deste estudo foi examinar a organização das passadas do andar, em bebês com diferentes experiências no andar, durante a ultrapassagem de um obstáculo. Trinta bebês foram distribuídos de acordo com o tempo de aquisição do andar independente em 3 grupos: 1, 3 e 6 meses de experiência no andar. A tarefa consistiu em caminhar sobre uma passarela em 2 condições experimentais: sem e com um obstáculo de espuma com 2 cm de altura e 3 cm de largura. Marcas foram afixadas nos centros articulares dos membros inferiores dos bebês e o andar foi filmado no plano sagital para ambos os lados, simultaneamente. Três ciclos para o andar normal, três para a perna de abordagem e três para a perna de suporte foram digitalizados utilizando o sistema APAS. Com base nas informações espaciais e temporais, comprimento, duração, cadência, velocidade, duração das fases de suporte e de balanço e fase relativa entre os membros foram calculadas. Ainda, as distâncias horizontal e vertical entre pé e obstáculo foram calculadas para as pernas de abordagem e de suporte. Os resultados indicaram que os bebês do grupo 1 mostraram passadas mais curtas e mais lentas do que os bebês dos grupos 2 e 3. Ainda, bebês do grupo 1 mostraram fase de suporte maior do que bebês do grupo 2. Quando os bebês tiveram que ultrapassar o obstáculo, mostraram passadas mais curtas e mais lentas do que na situação sem obstáculo. Ainda, bebês dos grupos 2 e 3 apresentaram cadência menor durante a passada com obstáculo e fase de suporte e fase de suporte simples menores no momento da ultrapassagem e fase de segundo duplo suporte maior após a ultrapassagem do obstáculo para a perna de abordagem. Também diminuíram a porcentagem da fase relativa referente a coordenação intermembros para a perna de abordagem e mostraram pequenas alterações no padrão coordenativo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this study was to examine the step walking organization during obstacle avoidance in infants with different walking experience. Thirty infants were distributed into trree groups according with their independent walking experience: one, three and six months of walking experience. The task consisted of walking in a runway in two experimental conditions: without and with a foam obstacle with 2 cm high and 3 cm wide. Markers were placed on the joint centers in both infants' lower extremity and walking performances were videotaped in the sagittal plane for both sides, simultaneously. Three cycles for normal walking, three for supportive leg and three for approaching leg were digitized using the APAS system. Based on the espacial and temporal information, stride length, duration, cadence, velocity, duration of support and swing phases and relative phase between limb were calculated. The horizontal and vertical distances between foot and obstacle were also calculated for both supportive and approaching legs. The results indicated that the infants of group 1 walked with shorter stride length and slower velocity than the infants of group 2 and 3.The first group showed support phase greater than the second group. When infants had to step over the obstacle, they walked with shorter stride and slower velocity than when they did not have to step over the obstacle. Furthermore, the infants from group 2 and 3 showed lower cadence than infants from group 1 when stepping over the obstacle and smaller support and single support phases during stepping over the obstacle and second double support phase greater after stepping over the obstacle for the approaching leg. Also, the phase relative percentage regarding interlimb coordination for approaching limb was smaller and few variations in coordination pattern between the shank and thigh segments for approaching... (Complete abstract, click electronic address below) / Mestre

Cognitive and motor impairments have been identified as signs following a concussion which may compromise the performance of everyday tasks or physical activities. However, little work has been done in the adolescent population using laboratory based measurements of attention or balance control to identify recovery from concussion. Therefore, the purpose of this dissertation was to prospectively and longitudinally observe how individuals who have sustained a concussion recover on measures of attention and gait balance control in comparison to individually matched, healthy control subjects from within 72 hours of injury up to two months following injury. Individuals were identified as sustaining a concussion by healthcare professionals and began participation in the study within 72 hours of injury. They then returned to the laboratory at approximately 1 week, 2 weeks, 1 month, and 2 months post-injury. Control subjects were individually matched by sex, age, height, and weight and tested in similar time increments. Attentional abilities were measured via multiple computerized testing assessments, and gait balance control was measured with whole-body motion analysis. The results indicated that following concussion, adolescents display deficits in conflict resolution ability, task switching ability, and gait balance control during dual-task walking for a time period of up to two months following injury in comparison to a matched control group. During dual-task walking, the complexity of the cognitive task performed may affect adolescents with concussion to a greater degree than matched control subjects. Adolescents also displayed regressions to gait stability recovery following their return to physical activities. Finally, adolescents with concussion displayed greater gait balance control deficits than young adults with concussion throughout the two months of testing when each group was compared to a respective healthy control group. Results from this dissertation indicate that concussion affects cognitive and motor functions in adolescents, who display deficits throughout two months post-injury. Computerized attentional tests and dual-task dynamic balance control assessments represent a multifaceted approach to concussion management and may provide another assessment battery for healthcare professionals to utilize in order to identify recovery following concussion. This dissertation includes previously published/unpublished co-authored material.

Stair locomotion is one of the most difficult and challenging type of locomotion for older adults, with a high risk of fall and injuries. A major reason is that the neuromuscular system undergoes various changes through the aging process. The aim of this doctoral thesis is to study the age-related neuro-mechanical adjustments associated with stair locomotion and more specifically to investigate the interaction between neural and muscular changes in the plantarflexor muscles. To that aim, three main projects have been performed. The first two projects investigated the influence of age on spinal and supraspinal excitability when individuals stood at the bottom and the top of a 3-steps staircase and spinal excitability during stair locomotion. The third one focused on the age-related influence on the muscle-tendon behavior during stair locomotion. The result of the first project indicate a lower dependence on spinal pathway to control soleus motoneurons with a similar change observed in both age groups suggesting that healthy older adults preserved their ability to adjust postural control to environmental demands. The second project is the first to report the modulation of H-reflex amplitude in the plantarflexor muscles during stair ascent and descent in healthy young and older adults. This modulation likely reflects an increased role of descending inputs in controlling plantarflexor muscle activation during the stair gait cycle. However, similarly to the first project the modulation of the net excitatory inputs from group I afferents during the stair gait cycle does not seem to be influenced by healthy aging. The third project suggest that length changes of the Achilles tendon and lateral gastrocnemius (LG) fascicles favour the storage and recovery the tendon elastic strain energy over the muscle work, improving thereby the mechanical efficiency of stair ascent in young adults. In older adults, it seems that a different behavior is used to maintain a mechanical efficiency during stair ascent. In contrast, during stair descent, no difference was observed between age groups regarding the LG muscle-complex behavior despite some kinematics changes. In conclusion, this doctoral thesis indicates that despite some age-related structural and functional changes of the neuromuscular system, similar neural modulations occur during stair locomotion in young and healthy older adults. During stair ascent, a similar global pattern of change in length for the fascicle’s length and the modulation of the H reflex can be observed. However, during stair descent, H reflex modulation cannot be simply explained by the pattern of muscle length change. / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished

A eficiência mecânica da corrida (Eff) é considerada um preditor de desempenho para essa atividade, pois explica características referentes à biomecânica e ao metabolismo energético do corredor. A resposta dessa variável a partir da intervenção de um treinamento ainda tem sido pouco explorada pela literatura específica. Sabe-se que o treinamento combinado de força com resistência pode influenciar positivamente no desempenho da corrida. Com isso, o objetivo do presente estudo foi comparar as respostas da Eff, economia e desempenho de corrida antes e após a inclusão de um treinamento de força máxima e força rápida de 8 semanas em corredores recreacionais. Foram selecionados 24 corredores recreacionais (19 homens, 5 mulheres), os quais foram divididos em 3 grupos submetidos a um treinamento de 8 semanas. O grupo FM, que adicionou o treinamento de força máxima ao treinamento de resistência (n = 8); grupo FR, que incluiu o treinamento de força rápida além do resistência (n = 9); e o grupo controle (C) que manteve somente o treinamento de resistência (n = 7). Os testes para variáveis biomecânicas e metabólicas foram realizados em uma esteira rolante. Para análise do desempenho, avaliou-se o tempo de prova em um circuito aberto de 5 km (t5km). A Eff foi avaliada em duas intensidades (60 - Eff60% - e 110% - Eff110% da velocidade do VO2máx). A Eff na maior intensidade foi definida de duas formas: assumindo componente anaeróbio (Eff110TOT), e desconsiderando a participação anaeróbia como fonte de energia (Eff110AER). Aplicou-se o teste de Shapiro-Wilk para verificar a normalidade dos dados. Utilizou-se um teste de ANOVA com medidas repetidas 3x2. Para os dados não paramétricos utilizou-se o teste de Friedman. Ocorrendo interação, aplicou-se o teste Post-Hoc de Tukey uma ANOVA One-Way. Em dados não paramétricos utilizou-se o teste Kruskal-Wallys. Além disso, o teste-T pareado foi utilizado para comparação intra grupos antes e após o programa de treinamento, em caso de dados não paramétricos, utilizou-se o teste de Wilcoxon. O tamanho do efeito foi calculado para as principais variáveis de desempenho. O alfa adotado foi de 5%. A Eff não apresentou diferenças significativas em nenhuma das intensidades e métodos calculados entre os grupos após 8 semanas de treinamento (p > 0,05). No entanto, apresentou um tamanho de efeito forte para FR (0,78) e moderado para FM (0,29) na Eff60%. Enquanto isso, tanto para Eff110AER, como para Eff110TOT, ambos os grupos FM e FR apresentaram tamanho de efeito moderado: FM = 0,44 e 0,34, respectivamente; FR = 0,26 e 0,30, respectivamente. O t5km apresentou diminuição significativa pré e pós-treinamento para os grupos FM e FR (p = 0,03 e p = 0,02, respectivamente). Para ECO, FR foi menor do que C (p < 0,01), e o grupo FM diminuiu a ECO após as 8 semanas de treinamento (p = 0,045). Eff não apresentou diferenças significativas nas diferentes intensidades nos grupos submetidos ao treinamento de força, o grupo FR e FM obtiveram um tamanho de efeito moderado-forte nessas respostas, que podem ser explicadas pela otimização de alguns parâmetros biomecânicos e metabólicos. O grupo FM incrementou a intensidade da vVO2máx e mesmo assim manteve o dispêndio metabólico, demonstrando um comportamento positivo na Eff. O grupo FR manteve a intensidade da vVO2máx, porém, otimizou suas variáveis biomecânicas, causando um aumento na potência mecânica, sem a necessidade do acréscimo no dispêndio metabólico. Os resultados provavelmente auxiliaram na melhora significativa apresentada em uma prova de 5 km para os grupos FM e FR após 8 semanas de treinamento. / The mechanical efficiency of running (Eff) is considered a predictor of performance this activity because explain biomechanics and energetics characteristics of runners. This variable has been little attention of the researches influenced by training program. It is known that combined strength and endurance training may be to influence positively in the running performance, through of metabolic and biomechanical responses. The objective of the present study was to compare two strength training programs in the Eff, running economy (ECO) and performance after 8 weeks of program training. 24 recreational runners were selected (males = 19; females = 5), and subdivided into three groups submitted to 8 weeks of training. The FM group, which added the maximal strength training to the endurance training (n = 8); FR group, which was submitted to the explosive strength training to the endurance training (n = 9); and C group, which performed endurance training only (n = 7). The tests for biomechanical and metabolic variables and to posterior Eff calculation were performed on treadmill. In addition, the performance was analyzed by the 5 km time in open field (t5km). The Eff was evaluated in two intensities (60% - Eff60% - and 110% of VO2máx velocity). At the higher intensity Eff was defined of two ways: with the presence (Eff110TOT) and the absence of anaerobic component (Eff110AER) as energy source. The Shapiro-Wilk test was performed to verify the data normality. The repeated measures ANOVA test (3x2) was used to detect interaction between group vs time factors. In non-parametric data, was used a Friedman test. If an interaction existed, Tukey’s Post-hoc test and one-way ANOVA were used. The Kruskal-Wallys test was utilized in non parametric cases. Furthermore, the paired Ttest was used to compare each group before and after the strength training program. Into nonparametric data was used the Wilcoxon test. The effect size was calculated to the main performance variables. The alpha adopted was 0.05. No significant changes were observed in Eff by intensities and methods calculated between the groups after 8 weeks of training (p > 0.05). However, FR group showed a stronger effect size (0.78) and FM group a moderated effect size (0.29) for Eff60%. Meanwhile, so much Eff110AER as Eff110TOT, both of groups FM and FR presented moderated effect size: FM = 0.44 and 0.34, respectively; FR = 0.26 and 0.30, respectively. The t5km showed significative decrease after training for the FM e FR groups (p = 0.03 and p = 0.02, respectively). The ECO showed lower for FR than C group (p < 0,01), and the FM group decreased ECO after 8 weeks training (p = 0.045). Eff did not show significative differences in different intensities on the groups submitted to strength training, the FM and FR groups obtained a moderated-stronger effect size in this responses, which could be justified by the optimization of biomechanical and metabolic parameters in such intensity. Thus, the FM group increased the vVO2máx intensity and still remained the energy expenditure, showing a improve behavior in Eff. Moreover, the FR group have maintained the vVO2máx intensity, however the biomechanical variables were adjusted, causing a mechanical power increased without metabolic expenditure added. These results probably assisted in the significative improvement showed a 5 km race for the FM and FR groups after 8 weeks of training.

abstract: As the robotic industry becomes increasingly present in some of the more extreme environments such as the battle field, disaster sites or extraplanetary exploration, it will be necessary to provide locomotive niche strategies that are optimal to each terrain. The hopping gait has been well studied in robotics and proven to be a potential method to fit some of these niche areas. There have been some difficulties in producing terrain following controllers that maintain robust, steady state, which are disturbance resistant. The following thesis will discuss a controller which has shown the ability to produce these desired properties. A phase angle oscillator controller is shown to work remarkably well, both in simulation and with a one degree of freedom robotic test stand. Work was also done with an experimental quadruped with less successful results, but which did show potential for stability. Additional work is suggested for the quadruped. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2015

The HPLC and LC/MS analyses of the CNS from isopod crustacean the woodlouse, Porcellio scaber revealed a presence of the red pigment-concentrating hormone (Panbo-RPCH) in this species. It has been shown that this neuropeptide plays a role in mobilization of energy stores: topical treatments of P. scaber individuals by Panbo-RPCH in a concentration 20 pmol/{$\mu$}l increased the level of glucose in haemolymph about 4 times. Glucose was the main carbohydrate mobilized by the Panbo-RPCH treatment. Despite the demonstration of hyperglycaemic activity of Panbo-RPCH, no stimulatory effect of this hormone on the locomotory activity of P. scaber was observed. The present study is the first discovery of an occurrence of Panbo-RPCH and its hyperglycaemic activity in the representative of the isopod crustacean.