Adaptation of motor control to training and disuse : contribution of muscle synergy analysis and movement variability

The well-known degrees of freedom problem originally introduced by Nikolai Bernstein (1967) results from the high abundance of degrees of freedom in the musculoskeletal system. Such abundance in motor control have two sides: i) because it is unlikely that the Central Nervous System controls each degree of freedom independently, the complexity of the control needs to be reduced, and ii) because there are many options to perform a movement, a repetition of a given movement is never the same. It leads to two main topics in motor control and biomechanics: motor coordination and motor variability. The present thesis aimed to understand how motor systems behave and adapt under specific conditions. This thesis comprises three studies that focused on three topics of major interest in the field of sports sciences and medicine: expertise, injury risk and fatigue. The first study (expertise) has focused on the muscle coordination topic to further investigate the effect of expertise on the muscle synergistic organization, which ultimately may represent the underlying neural strategies. Studies 2 (excessive medial knee displacement) and 3 (fatigue) both aimed to better understand its impact on the dynamic local stability. The main findings of the present thesis suggest: 1) there is a great robustness in muscle synergistic organization between swimmers at different levels of expertise (study 1, chapter II), which ultimately indicate that differences in muscle coordination is mainly explained by peripheral adaptations; 2) injury risk factors such as excessive medial knee displacement (study 2, chapter III) and fatigue (study 3, chapter IV) alter the dynamic local stability of the neuromuscular system towards a more unstable state. This change in dynamic local stability represents a loss of adaptability in the neuromuscular system reducing the flexibility to adapt to a perturbation.

Competências extra-musicais solicitadas na obra para clarinete solo Der Kleine Harlekin de Karlheinz Stockausen

O objeto de estudo do presente trabalho é a obra Der kleine Harlekin para clarinete solo do compositor Karlheinz Stockhausen. Dada a falta de coesão sentida ao longo da obra aquando da visualização das seis gravações disponíveis, surgiu a necessidade de analisar o papel da consciência corporal do músico na performance, a aproximação da obra à commedia dell' arte e, consequentemente, a temática da utilização da máscara durante a mesma. Paralelamente, o trabalho apresenta ainda uma análise pormenorizada de todas as indicações disponíveis nas intruções da obra, bem como uma conexão entre a liberdade presente em cada uma dessas indicações e a compreensão de uma narrativa ao longo da performance por parte do público, dando especial atenção à ação como elemento base das escolhas interpretativas; Extra-musical skills in the works of musical theater for solo clarinet Abstract: This is an investigation into the piece Der kleine Harlekin for clarinet solo by Karlheinz Stockhausen. Six recordings were analysed and it was possible to understand that, at some moments, there is no cohesion throughout the all work. Thus, an analysis is made on the importance of body awareness, the approach to commedia dell' arte and, thereafter, the use of the mask on performance. Furthermore, the work also presents a detailed analysis of all the information available in the work instructions as well as a connection between their freedom and the understanding of a narrative throughout the performance by the public, giving special attention to the action as a base element of the interpretative choices.

Monitorização da vegetação infestante em arrozais e prospeção de resistência a herbicidas em Echinochloa spp.

Mestrado em Engenharia Agronómica - Especialização em Proteção das plantas - Instituto Superior de Agronomia - UL