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Brain-muscle coupling and intermuscular coordination in high-speed knee movements performed to fatigue and their role on hamstring strain injuries
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Orientador(es)
Resumo(s)
A diminuição da frequência gestual dos dedos com movimentos repetitivos de máxima velocidade (motor slowing) tem demonstrado uma resposta consistente e uma forte dependência do controlo supraspinal. O estudo de um segmento maior permitiria estabelecer um comportamento comum de motor slowing mas também mecanismos regulatórios centrais e periféricos do exercício. O movimento rápido das pernas é também um mecanismo relevante de lesão dos isquiotibiais no futebol, e as suas repercussões supraespinais permanecem inexploradas. Este projeto teve como objetivo: i) caracterizar o motor slowing das pernas, a sua fiabilidade, e a eletrofisiologia associada; ii) determinar se uma tarefa simples de motor slowing diferencia futebolistas com e sem historial de lesões nos isquiotibiais; e iii) investigar as diferenças na atividade cerebral e muscular entre jogadores de futebol com e sem historial de lesões nos isquiotibiais. Foi realizada uma revisão da literatura para estabelecer o conhecimento atual sobre o controlo de movimentos rápidos. A execução correta da tarefa, dados normativos de motor slowing das pernas e a eletrofisiologia cerebral e muscular associada foram estabelecidos em indivíduos saudáveis. A mesma tarefa foi aplicada em futebolistas, onde aqueles com lesão prévia nos isquiotibiais apresentaram uma frequência gestual mais alta, atividade cerebral demonstrativa de uma maior carga cognitiva e uso de recursos atencionais, e atividade muscular e co-contração agonista-antagonista mais reduzidas. Finalmente, o motor slowing dos dedos e das pernas foi comparado em futebolistas; embora ambos tenham mostrado uma trajetória semelhante, houve uma maior perda nos dedos. As principais conclusões são: i) a frequência gestual das pernas pode ser medida de forma fiável e mostra um padrão claro de motor slowing associado a diminuições na atividade cerebral após um pico inicial, diminuição da atividade muscular agonista e da coerência corticomuscular com fadiga; ii) a tarefa usada foi capaz de diferenciar futebolistas com e sem historial de lesão nos isquiotibiais; e iii) futebolistas com lesões anteriores nos isquiotibiais mostram um maior uso de recursos centrais e menor atividade muscular durante uma tarefa de máxima velocidade
The decrease in finger movement rate with maximum-speed repetitive limb movement (i.e., motor slowing) has shown a consistent response and a strong supraspinal control dependence. Studying a larger segment would have implications not only for establishing a common motor slowing behavior but also for central and peripheral maximal exercise regulation mechanisms. Additionally, high-speed leg movement is also a relevant hamstring injury mechanism in football, and the supraspinal repercussions of these injuries remain unexplored. This project aimed to i) characterize the leg motor slowing, its measurement reliability, and its associated electrophysiology; ii) determine whether a simple motor slowing task can differentiate footballers with and without hamstring injury history; and iii) investigate differences in brain and muscle activity between footballers with and without hamstring injury history. A literature review was first conducted to establish the current knowledge on fast movement control. Next, correct task execution and normative data for the leg motor slowing response and the associated brain and muscle electrophysiology were established in healthy individuals. The same task was then applied in footballers, where those with previous hamstring injury showed a higher movement rate, brain activity suggesting higher task cognitive load and attentional resource use, and lower muscle activity and agonistantagonist co-contraction. Finally, finger and leg motor slowing were compared in footballers; although both showed a similar trajectory, there was a greater finger motor slowing. The main conclusions are i) leg movement rate can be measured reliably and shows a clear motor slowing pattern associated with brain activity decreases after an initial peak, decreasing agonist muscle activity, and decreasing corticomuscular coherence with fatigue; ii) a simple maximum-speed movement task was able to differentiate footballers with and without hamstring injury history; and iii) footballers with previous hamstring injury show a greater central resource use and lower muscle activity during a maximum-speed task.
The decrease in finger movement rate with maximum-speed repetitive limb movement (i.e., motor slowing) has shown a consistent response and a strong supraspinal control dependence. Studying a larger segment would have implications not only for establishing a common motor slowing behavior but also for central and peripheral maximal exercise regulation mechanisms. Additionally, high-speed leg movement is also a relevant hamstring injury mechanism in football, and the supraspinal repercussions of these injuries remain unexplored. This project aimed to i) characterize the leg motor slowing, its measurement reliability, and its associated electrophysiology; ii) determine whether a simple motor slowing task can differentiate footballers with and without hamstring injury history; and iii) investigate differences in brain and muscle activity between footballers with and without hamstring injury history. A literature review was first conducted to establish the current knowledge on fast movement control. Next, correct task execution and normative data for the leg motor slowing response and the associated brain and muscle electrophysiology were established in healthy individuals. The same task was then applied in footballers, where those with previous hamstring injury showed a higher movement rate, brain activity suggesting higher task cognitive load and attentional resource use, and lower muscle activity and agonistantagonist co-contraction. Finally, finger and leg motor slowing were compared in footballers; although both showed a similar trajectory, there was a greater finger motor slowing. The main conclusions are i) leg movement rate can be measured reliably and shows a clear motor slowing pattern associated with brain activity decreases after an initial peak, decreasing agonist muscle activity, and decreasing corticomuscular coherence with fatigue; ii) a simple maximum-speed movement task was able to differentiate footballers with and without hamstring injury history; and iii) footballers with previous hamstring injury show a greater central resource use and lower muscle activity during a maximum-speed task.
Descrição
Doutoramento em Motricidade Humana na especialidade de Comportamento Motor. Universidade de Lisboa. Faculdade de Motricidade Humana
Palavras-chave
Electroencephalography Electromyography Fatigue Hamstring strain injury Motor slowing Eletroencefalografia Eletromiografia Fadiga Lesão dos isquibiais Motor slowing