<p>U tezi je prikazan novi metod za sintezu i realizaciju dvonožnog<br />veštačkog hoda koji se zasniva na upotrebi jednostavnih pokreta čijim<br />je kombinovanjem moguće realizovati kompleksne pokrete kao što je<br />hod, a čiji se parametri mogu menjati tokom kretanja. Time je omogućeno<br />da se na osnovu informacija o nameravanom kretanju i stanja okoline<br />izvrši sinteza kretanja izborom i kombinacijom jednostavnih<br />bazičnih pokreta koje se nazivaju primitivi. Takođe je omogućeno da se,<br />tokom izvršavanja hoda bez njegovog prekida, menjaju parametri<br />kretanja kao što su brzina hoda, dužina koraka, pravac kretanja i<br />visina podizanja noge tokom prenosne faze. Potvrda je data kroz<br />eksperimentalne rezultate koji su sprovedeni simulacijom na<br />dinamičkom modelu humanoidnog robota.</p> / <p>This dissertation presents new method for the synthesis and realization of<br />biped artificial walk based on the use of simple movements that can be<br />combined in order to achieve complex movements such as walk, whereas it<br />is possible to change the motion parameters at any time. It means that,<br />based on the information about intended movement and current state of the<br />environment, it is possible to synthesize motion by selecting and tying simple<br />movements, i.e. motion primitives. It also enables the robot to change<br />walking parameters online such as walking speed, direction of walk, foot<br />length during swing phase and step length. Proof of this method is given by<br />experimental results obtained during the simulation on a dynamic model of<br />humanoid robot.</p>

Motility of flagellated bacteria has been a topic of increasing scientific interest over the past decades, attracting the attention of mathematicians, physicists, biologists and engineers alike. Bacteria and other micro-organisms cause substantial damage through biofilm growth on submerged interfaces in water cooling systems, ship hulls and medical implants. This gives social and economic motivations for learning about how micro-organisms swim and behave in different environments. Fluid flows on such small scales are dominated by viscosity and therefore behave differently from the inertia-dominated flows that we are more familiar with, making bacterial motility a physically intriguing phenomenon to study as well. We use the boundary element method (BEM) to simulate the motion of singly flagellated bacteria in a viscous, Newtonian fluid. One of our main objectives is to investigate the influence of external surfaces on swimming behaviour. We show that the precise shape of the cell body and flagellum can be important for determining boundary behaviour, in particular, whether bacteria are attracted or repelled from surfaces. Furthermore, we investigate the types of motion that may arise between two parallel plates and in rectangular channels of fluid and show how these relate to the plane boundary interactions. As an extension to original models of flagellar propulsion in bacteria that assume a rotation of the rigid helical flagellum about an axis fixed relative to the cell body, we consider flexibility of the bacterial hook connecting the aforementioned parts of the swimmer. This is motivated by evidence that the hook is much more flexible than the rest of the flagellum, which we therefore treat as a rigid structure. Elastic dynamics of the hook are modelled using the equations for a Kirchhoff rod. In some regimes, the dynamics are well described by a rigid hook model but we find the possibility of additional modes of behaviour.

In the spinal cord, an intricate neural network generates and coordinates the patterning of limb movements during locomotion. This network, known as the locomotor central pattern generator (CPG), comprises of various cell populations that together orchestrate the output of motor neurons. Identification of CPG neurons through their specific gene expression is a valuable tool that can provide considerable insight to the character, intrinsic properties and role of a population, which represents a step toward understanding locomotor circuit function and correlating neural activity to behaviour. We selectively targeted two inhibitory CPG populations to investigate their molecular characteristics, circuitry and functional role; Renshaw cells (RCs) marked by their specific expression of the cholinergic nicotinic receptor α2 (Chrna2) and a subset of the dI6 population derived by their selective expression of the Doublesex and mab-3 related transcription factor 3 (Dmrt3). We found that RCs have hyperpolarisation-activated cation (Ih) and small calcium-activated potassium (ISK) modulatory currents that differentially regulate their excitation and firing properties, which influence the instantaneous feedback to motor neurons through the recurrent inhibition circuit. Due to previous difficulties isolating RCs from the surrounding locomotor circuits, their functional role remains poorly defined. For the first time, we selectively silenced RC inhibition and found that all aspects of motor behaviour, including coordination and gait were normal. The deletion of RC signalling instead altered the electrical and synaptic properties of the recurrent inhibitory circuit, suggesting that developmental plasticity compensates for the loss of RC inhibition. We reveal Dmrt3 neurons comprise a population of glycinergic inhibitory, spike-frequency adapting commissural interneurons active during locomotion. Conditional silencing of the Dmrt3 population resulted in considerable gait abnormalities in the neonatal and adult mouse. This manifested as an uncoordinated CPG output in vitro, impaired limb coordination in pups and increased fore- and hindlimb synchrony in adults that was exacerbated at faster locomotor speeds. Dmrt3 mediated inhibition subsequently impacts locomotion and suggests the Dmrt3 population contribute to coordinating speed dependent left-right limb alternation. This thesis provides cellular, circuit and behavioural insights into the Renshaw cell and Dmrt3 populations and enhances our knowledge regarding their probable function within the locomotor CPG.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

La respiration est une activité motrice autonome rythmique au cours de laquelle de nombreux muscles se contractent de manière coordonnée afin de produire des mouvements ventilatoires adaptés aux contraintes environnementales et aux exigences de l'organisme. Cette fonction vitale doit être fiable et adaptable à très court terme, c’est pourquoi elle est influencée, entre autres, par un grand nombre d’activités motrices. Par exemple, lors d’exercices physiques, le rythme respiratoire peut se coupler au rythme locomoteur. Les objectifs de ce travail doctoral sont centrés sur l’exploration des mécanismes neurogènes à la base du couplage entre ces deux fonctions motrices chez le rat nouveau-né. Pour une grande partie, cette étude a été réalisée sur préparation isolée in vitro de tronc cérébral-moelle épinière de rat nouveau-né (0 à 3 jours), ce modèle permettant de conserver dans leur intégrité les centres responsables des rythmes respiratoire et locomoteur. Compte tenu de l’accessibilité directe aux réseaux neuronaux, les mécanismes de couplage et d'entraînement respiratoire ont été abordés par des approches combinées électrophysiologique, neuroanatomique, pharmacologique et lésionnelle. Dans ce contexte, un des principaux résultats de ce travail doctoral est le rôle crucial joué par les informations sensorielles en provenance des membres antérieurs et postérieurs dans l'entraînement respiratoire observé lors de séquences locomotrices. Ainsi, les afférences proprioceptives spinales capables de réinitialiser et d'entraîner l’activité des centres respiratoires bulbaires via un relais pontique, établissent également des connexions sur l’ensemble des populations de motoneurones spinaux respiratoires phréniques, intercostaux et abdominaux. / Respiration is an autonomous rhythmic motor activity that requires the coordinated contractions of diverse muscles to produce ventilatory movements adapted to organismal needs. This crucial physiological function must be reliable and adaptable on a short-term basis, and requires coordianted movements with various other motor activities. For instance, respiratory rhythmicity becomes coupled to locomotion during physical exercise. My doctoral work aimed to explore the neurogenic mechanisms underlying the interactions between these two motor functions in the neonatal rat. This work was mainly conducted on isolated in vitro brain stem-spinal cord preparations of newborn rats (0-3 days), an experimental model that allows the maintenance of the still functional respiratory and locomotor CPGs in vitro. Due to the easy access to the neuronal networks in these preparations, locomotor-respiratory coupling and respiratory entrainment mechanisms were investigated by combined electrophysiological, neuroanatomical, pharmacological and lesional approaches. A major finding was the crucial played by sensory information from fore- and hindlimb in respiratory entrainment induced by locomotor rythmicity. Spinal sensory afferents can reset and entrain the activity of the medullary respiratory centres via a pontine relay, as well as making direct connections with the various spinal respiratory motoneuron (phrenic, intercostal and abdominal) populations.

Thesis name: The evaluating of the change of walking quality in dancers in comparison with the normal population Thesis goal: This thesis deals with effect of long-term ballet dance on kinematic parameters of gait. The theoretical part includes basic characteristics of gait cycle and kinesiological and biomechanical findings of ballet movement and its compensatory mechanisms in musculoskeletal system. There is analyzed angular parameters of gait cycle in ballet dancers in performance of walking in the experimental part. The results will show if the many-years intensive training of dance affects the alignment of particular joints of the body during human walk. Method: Kinematic analysis by Qualisys system allowing automatic processing of record obtained with infrared cameras. Qualisys uses its own high-frequency cameras for precise movement tracking of the measured object using active or passive markers. Gathered data from device were processed and statictically evaluated with Microsoft Office Excel. Keywords: gait, bipedal locomotion, dance, gait analysis, gait of dancers, ballet, kinematics analysis

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Author's first name and surname: Michaela Opálková Title of the master thesis: Evaluation of selective voluntary muscle control in children with spastic cerebral palsy. Impact on the severity of spasticity and gross motor function level. Department: Department of rehabilitation and sports medicine, Charles University in Prague, 2nd Faculty of Medicine Supervisor: doc. PaedDr. Pavel Kolář, PhD. The year of presentation: 2012 Abstract: This thesis should provide comprehensive information about pathophysiological mechanisms underlying spasticity and spastic movement disorder with special attention to children with cerebral palsy. Spasticity and selective voluntary motor control assessment possibilities will be summarized. Classification systems of the gross motor functions (levels of locomotion) are also mentioned. The main objective is to elaborate selective motor control ability scale (IP) which is newly proposed in this study. The need for such instrument and its feasibility for clinical practice intend to be confirmed. The level of locomotion of 25 children with spastic cerebral palsy is compared with IP outputs, spasticity measurement outputs using Ashworth scale respectively. Keywords: spasticity, selective voluntary motor control, locomotion, scale

The aim of this thesis was to evaluate the influence of Vojta's reflex locomotion on the activity of the shoulder girdle's muscles with surface electromyography. We also observed the activity of some of the trunk's muscles. We tested phasic and support function of the upper extremity in several movements on 15 healthy people. It didn't bring many significant values. It could be caused by different sensitivities of the participants for the stimulation, the short time of the stimulation, individual motoric stereotypes or not so strongly expressed muscle dysbalantion within healthy individuals.

Title Gait Analysis in Adolescents with Idiopathic Scoliosis: A Systematic Review. Aim The role of spine is vital as a gait stabilizer. Gait analysis may provide a more holistic view of how the body behaves to idiopathic scoliosis among adolescents. The aim of this thesis is to review the effectiveness and validity of gait analysis in examining AIS, and secondly to assess how the gait of AIS patients differ from adolescents without scoliosis. Method A systematic review of the topic was conducted. Information was gathered from six e-databases, and seventeen articles were selected, of which seven focusing solely on AIS subjects (i.e. non-comparative) and ten were focusing on AIS in relation to control subjects (i.e. comparative). Results Spatio-temporal (STP), kinematic, kinetic and EMG parameters show significant changes in AIS subjects during walking. But variations between results, lack of data for certain parameters and no significant relationship between gait parameters and scoliosis was also seen. Furthermore, AIS subjects differ in performance compared to non-scoliosis adolescents in at least one gait parameter across all studies. This includes abnormalities in muscle activity, less economical use of the body, poorer performance in kinematic parameters and differences in STP such as step...