Repetitive stress injuries are common in the workplace where workers perform repetitive tasks continuously throughout the day. Muscle fatigue may lead to injury either directly through muscle damage or indirectly through changes in coordination, development of muscle imbalances, kinematic and muscle activation variability, and/or movement instability. To better understand the role of muscle fatigue in changes in movement parameters, we studied how muscle fatigue and muscle imbalances affected the control of movement timing, variability, and stability during a repetitive upper extremity sawing task. Since muscle fatigue leads to delayed muscle and cognitive response times, we might expect the ability to maintain movement timing would decline with muscle fatigue. We compared timing errors pre- and post-fatigue as subjects performed this repetitive sawing task synchronized with a metronome using standard techniques and a goalequivalent manifold (GEM) approach. No differences in basic performance parameters were found. Significant decreases in the temporal correlations of the timing errors and velocities indicated that subjects made more frequent corrections to their movements post-fatigue. Muscle fatigue may lead to movement instability through a variety of mechanisms including delayed muscle response times and muscle imbalances. To measure movement stability, we must first define a state space that describes the movement. We compared a variety of different state space definitions and found that state spaces composed of angles and velocities with little redundant information provide the most consistent results. We then studied the affect of fatigue on the shoulder flexor muscles and general fatigue of the arm on movement stability. Subjects were able to maintain stability in spite of muscle fatigue, shoulder strength imbalance and decreased muscle cocontraction. Little is known about the time course for adaptations in response to fatigue. We studied the effect of muscle fatigue on movement coordination, kinematic variability and movement stability while subjects performed the same sawing task at two work heights. Increasing the height of the task caused subjects to make more adjustments to their movement patterns in response to muscle fatigue. Subjects also exhibited some increases in kinematic variability at the shoulder but no changes in movement stability. These findings suggest that people alter their kinematic patterns in response to fatigue possibly to maintain stability at the expense of increased variability. / text

In my thesis I concern with the use of motoric activities in math classes. The chapters that offer a range of motoric activities were processed on the base of a questionnaire and an experiment. Some of the activities are currently being implemented in math classes by teachers of first, second and third grades at primary schools, others are part of textbooks designed for this age group. In addition to that, I offer five more possible activities, which have been recorded and interpreted within six experiments. The goal of the thesis is to demonstrate that physical movement cannot be separated from the life of six to nine years old children, and offer some motoric activities, which can potentially be contributive for development of mathematical skills and abilities.

In this thesis, we present a dynamical systems analysis of models of movement coordination, namely the Haken-Kelso-Bunz (HKB) model and the Jirsa-Kelso excitator (JKE). The dynamical properties of the models that can describe various phenomena in discrete and rhythmic movements have been explored in the models' parameter space. The dynamics of amplitude-phase approximation of the single HKB oscillator has been investigated. Furthermore, an approximated version of the scaled JKE system has been proposed and analysed. The canard phenomena in the JKE system has been analysed. A combination of slow-fast analysis, projection onto the Poincare sphere and blow-up method has been suggested to explain the dynamical mechanisms organising the canard cycles in JKE system, which have been shown to have different properties comparing to the classical canards known for the equivalent FitzHugh-Nagumo (FHN) model. Different approaches to de fining the maximal canard periodic solution have been presented and compared. The model of two HKB oscillators coupled by a neurologically motivated function, involving the effect of time-delay and weighted self- and mutual-feedback, has been analysed. The periodic regimes of the model have been shown to capture well the frequency-induced drop of oscillation amplitude and loss of anti-phase stability that have been experimentally observed in many rhythmic movements and by which the development of the HKB model has been inspired. The model has also been demonstrated to support a dynamic regime of stationary bistability with the absence of periodic regimes that can be used to describe discrete movement behaviours.

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La fatigue musculaire est un phénomène transitoire communément expérimenté dans la vie quotidienne. Principalement associée à un déficit de production de force, elle s’accompagne également d’une augmentation de l’effort mental à fournir pour déployer un niveau de force particulier. L’augmentation du taux de décharge des afférences nociceptives de petit diamètre (groupes III et IV) lors de contractions fatigantes modifie l’expression des commandes motrices – notamment en raison de processus inhibiteurs associés à leur intégration aux niveaux spinal et supraspinal – ce qui affecte finalement la production motrice. C’est la raison pour laquelle une intention motrice similaire avec et sans fatigue se traduira par des formes gestuelles différentes. Une problématique qui n’a jusque-là jamais été abordée dans la littérature concerne la capacité du Système Nerveux Central (SNC) à anticiper les effets de la fatigue musculaire de façon prédictive. Cette capacité prédictive sera étudiée dans ce travail de thèse au moyen de paradigmes expérimentaux faisant intervenir des processus de contrôle prédictifs de la posture, i.e. les Ajustements Posturaux Anticipés (APAs). Du fait que de nombreux travaux montrent que les APAs sont modulés en fonction des caractéristiques mécaniques du mouvement à venir, l’altération des capacités des muscles focaux grâce à des protocoles de fatigue maîtrisés nous a permis d’apprécier la capacité du SNC à en prédire les effets. Nous verrons que cette capacité est condition-dépendante, à savoir qu’elle dépend de la nature des contractions effectuées (volontaires vs. électro-induites) et du niveau de contraintes cognitives et temporelles imposées lors de la préparation du mouvement / Muscle fatigue is a transient and commonly experienced phenomenon. It is mainly associated with loss of force and leads to higher effort to produce a particular force level. The increased discharge rate of the nociceptive afferents (group III and IV) during fatiguing contractions alters motor command expression and finally motor production. An issue that has never been addressed in the literature is the Central Nervous System (CNS) capacity to anticipate muscle fatigue effects in a predictive fashion. This predictive capacity will be investigated thanks to experimental paradigms involving postural predictive processes of control, namely Anticipatory Postural Adjustments (APAs). Because numerous works show that APAs are modulated as a function of the mechanical properties of the upcoming movement, the induction of muscle fatigue at the levels of the focal muscles allowed us to appreciate the CNS capacity to predict muscle fatigue effects. We will demonstrate that this capacity is condition-dependent, i.e. it depends on the nature of the fatiguing contractions performed (voluntary vs. electro-induced) and on the level of cognitive and temporal constraints during movement preparation

Title: The Assessment of the Impact of the Sports Aerobics on the Postural Stabilization of the girls aged 8 to 10 years Definition of the problem: This thesis deals with testing of the postural stabilization and also deals with detection of the occurrence of hypermobility in two groups of girls aged 8-10 years. The first group consist of girls that do sports aerobics and second group consist of girls that do not do any sport. Objectives: In the theoretical part I will devote a summary of findings on the development of postural security, with motor development and motor learning and also very briefly the hypermobility. The aim is to verify if the sports aerobics has a formative influence on postural stabilization of girls at a school age. I examine if the high training load at this early age leads to changes in postural motor skills in terms of its positive or negative influence. Furthermore, the research confirms the higher incidence of hypermobility among athletes. Methods: Selection of the research group on a voluntary basis and according to predetermined criteria. Practical testing of children assembled using two test batteries. Statistical data processing (Student's t-test, Spearman's correlation coefficient). Comparing the results between the two groups of girls. Results: Two test sets...

O Tiro com Arco é uma modalidade olímpica na qual os atletas exibem diversas estratégias de coordenação muscular na preparação do disparo da flecha, principalmente no período da liberação do clicker, tornando dificultosa a interpretação da coordenação de arqueiros no que tange à sua pontuação. Deste modo, algumas técnicas, como a Análise de Vetor Codificado e co-ativação/inibição recíproca, provenientes de abordagens de Controle Motor, podem ajudar-nos a desvendar quais parâmetros em comum que estes arqueiros utilizam quando atiram e sua relação com seu desempenho obtido durante o disparo sequencial de flechas. O objetivo do trabalho foi o de avaliar a coordenação muscular utilizada por arqueiros da seleção brasileira durante uma simulação qualificatória olímpica, através da técnica eletromiográfica. Participaram 11 arqueiros da seleção brasileira; idade: 25,2±4,9 anos, altura: 1,72±0,12m, peso: 68,6±11,8 kg, FITA score: 1258±43 pontos, Qualificação: 632±20 pontos, Flecha média: 8,7±0,3 pontos. A análise EMG foi dividida em 0,5s antes e 0,15s após a liberação do clicker. Foi utilizado o valor RMS deste sinal de doze músculos: no lado que traciona a corda (dominante) - FSD (Flexor Superficial dos dedos); ED (Extensor dos dedos); BBL (Bíceps Braquial); TBL (Tríceps Braquial Cabeça longa); GD (Grande Dorsal) PMC (Peitoral Maior Clavicular); TS (Trapézio Superior); SAD (Serrátil Anterior); RA (Reto Abdominal) e ML (Multífido Lombar). Lado não dominante (nD) DPnD (Deltóide Posterior); SAnD (Serrátil Anterior), no qual foram criados em 14 pares de análise (agonista-antagonista: FSD-ED; BBL-TBL; GD-PMC; TS-SAD; RA-ML; distal-proximal: FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; e mistos: PMC-SAD; GD-TS; SAD-SAnD; SAnD-DPnD; GD-DPnD), para a análise dentro das técnicas de Co-ativação/Inibição Reciproca e Análise de Vetor Codificado. Nos resultados; oito pares (FSD-ED; BBL-TBL; TS-SAD; FSD-BBL; FSD-TBL; ED-TBL; SAD-SAnD; SAnD-DPnD) co-ativaram diferentemente na transição de blocos (p<0.05); e 12 (FSD-ED; BBL-TBL; GD-PMC; TS-SAD; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; PMC-SAD; SAD-SAnD; SAnD-DPnD; GD-DPnD) co-ativaram diferentemente na comparação do escore obtido (p<0.05). Em nove pares, os arqueiros, evidenciaram diferentes estratégias de inibição recíproca na transição de blocos (FSD-ED; BBL-TBL; TS-SAD; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; SAD-SAnD; SAnD-DPnD) (p<0.05); um (TS-SAD) na análise de flechas (p<0.05); e nove (FSD-ED; BBL-TBL; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; SAD-SAnD; SAnD-DPnD; GD-DPnD) na análise do escore. A análise de Vetor Codificado apresentou que, no total de flechas disparadas nove pares (FSD-ED; GD-PMC; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; PMC-SAD; SAD-SAnD; SAnD-DPnD) mudaram a moda de fase de coordenação na transição de ajustes posturais, enquanto no desempenho 11 pares (FSD-ED; BBL-TBL; GD-PMC; TS-SAD; FSD-BBL; FSD-TBL; ED-BBL; ED-TBL; PMC-SAD; SAD-SAnD; SAnD-DPnD) evidenciaram tais mudanças. As técnicas apresentadas no presente estudo revelaram parâmetros em comum associados com as sequências temporais de disparo de flechas e com os escores obtidos por arqueiros de elite, isto corrobora com a complexidade da análise do desempenho em atletas de alto rendimento, contudo também colocam a disposição técnicas que ajudam na filtragem e verificação desses parâmetros outrora divergentes / Archery is an Olympic sport in which the athletes exhibit several muscular coordination patterns in the arrow shooting, mainly in the clicker falls tempo, making difficult the interpretation of the coordination of archers in what concerns to their score. Thus, some techniques, such as Vector Coding and co-activation/reciprocal inhibition, from Motor Control approaches, can help us to discover what common patterns these archers use when firing and their relation to their obtained performance during the sequential firing of arrows. Aim: evaluate the muscular coordination used by archers of the Brazilian team during an Olympic qualifying simulation, using the electromyographic technique. Eleven archers of the Brazilian team participated; age: 25.2 ± 4.9 years, height: 1.72 ± 0.12m, weight: 68.6 ± 11.8 kg, FITA score: 1258 ± 43 points, Qualification: 632 ± 20 points, Mean arrow: 8.7 ± 0.3 points. The EMG analysis was divided in 0.5s before and 0.15s after the release of the clicker. The RMS value of this twelve-muscle signal was used: drawning arm (dominant side) - FDS (Flexor Digitorum Superficilis); ED (Extensor Digitorum); BB (Biceps Brachii); TBL (Triceps Brachii - Long Head); LD (Latissimus Dorsi) PMC (Pectoralis Major Clavicular Head); UT (Upper Trapezius); ASD (Anterior Serratus); RA (Rectus Abdominis) and LM (Lumbar Multifidus). Non-dominant side (nD) DPnD (Posterior deltoid) and ASnD (Anterior Serratus non-dominant side); pairs created (Agonist-Antagonist: FDS-ED, BBL-TBL, LD-PMC, UT-ASD, RA-LM; Distal-Proximal: FDS-BBL, FDS-TBL, ED-BBL, ED-TBL and the pairs glenohumeral-scapular: PMC-SAD, GD-TS, SAD-SAnD, SAnD-DPnD, GD-DPnD) for analysis of co-activation/reciprocal inhibition and Vector Coding. Results; eight pairs (FDS-ED, BB-TBL, UT-ASD, FDS-BB, FDS-TBL, ED-TBL, ASD-ASnD, ASnD-DPnD) coactivated differently in blocks transition (p<0.05); and 12 (FDS-ED, BB-TBL, LD-PMC, UT-ASD, FDS-BB, FDS-TBL, ED-BB, ED-TBL, PMC-ASD, ASD-ASnD, ASnD-DPnD, LD-DPnD) co-activated differently in the score comparison (p<0.05). Also, the archers displayed different strategies of reciprocal inhibition in the blocks transition (FDS-ED, BB-TBL, UT-ASD, FDS-BB, FDS-TBL, ED-BBL, ED-TBL, ASD-ASnD; ASnD-DPnD) (p<0.05); one (UT-ASD) in the arrow analysis (p<0.05); and nine (FDS-ED, BB-TBL, FDS-BBL, FDS-TBL, ED-BBL, ED-TBL, ASD-ASnD, ASnD-DPnD, LD-DPnD) in the score analysis. Nine Vector Coding pairs (FDS-BB, FDS-TBL, ED-BB, ED-TBL, PMC-ASD, ASD-ASnD, ASnD- DPnD) changed the coordination phase mode in postural adjustments transition, while 11 pairs (FDS-ED; BB-TBL; LD-PMC; UT-ASD; FDS-BB; FDS-TBL; ED-BB; ED-TBL, PMC-ASD, ASD-ASnD, ASnD-DPnD) showed such changes in score analysis. The techniques presented in the present study revealed common parameters associated with temporal shoot-out and scores obtained by elite archers, dispite the complexity of performance analysis in high-performance athletes