NEUROMUSCULAR PERFORMANCE OF DOLLYO CHAGUI: COMPARISON OF SUBELITE AND ELITE TAEKWONDO ATHLETES

Aiming to compare the execution time, linear and angular speeds, ground reaction force (GRF) and electromyographic (EMG) parameters between taekwondo athletes of two different standards, 8 elite and 8 subelite black belt taekwondo athletes performed eighteen round house kicks, in two randomized height (Head and Chest), with their dominant lower limb, combining maximum impact and speed, in a selective reaction time design. Kinematic were recorded through 3D kinemetry. Timing parameters and EMG cocontraction index were significantly lower in elite group, while peak of linear (toe and knee), angular speeds (knee and hip), and GRF were significantly higher in elite group. We conclude that reaction time, duration and velocity of kick and cocontraction could be useful in selecting top level taekwondo athletes and monitoring their training status

Consistency of pacing profile according to performance level in three different editions of the Chicago, London, and Tokyo marathons

[EN] Running pacing has become a focus of interest over recent years due to its relationship with performance, however, it is still unknown the consistency of each race in different editions. The aim of this study is to analyze the consistency of pacing profile in three consecutive editions of three marathon races. A database of 282,808 runners, compiled from three different races (Chicago, London, and Tokyo Marathon) and three editions (2017, 2018, and 2019) was analyzed. Participants were categorized according to their time performance in the marathon, every 30 min from 2:30 h to sub-6 h. The relative speed of each section for each runner was calculated as a percentage of the average speed for the entire race. The intraclass correlation coefficients (ICC) of relative speed at the different pacing section, taking into account the runner time categories, was excellent over the three marathon editions (ICC > 0.93). The artificial intelligence model showed an accuracy of 86.8% to classify the runners' data in three marathons, suggesting a consistency between editions with identifiable differences between races. In conclusion, although some differences have been observed between editions in certain sections and marathon runner categories, excellent consistency of the pacing profile was observed. The study of pacing profile in a specific marathon can, therefore, be helpful for runners, coaches and marathon organizers for planning the race and improving its organization.Oficial-Casado, F.; Uriel-Molto, J.; Jimenez-Perez, I.; Fagundes Goethel, M.; Pérez-Soriano, P.; Priego-Quesada, JI. (2022). Consistency of pacing profile according to performance level in three different editions of the Chicago, London, and Tokyo marathons. Scientific Reports. 12(1):1-9. https://doi.org/10.1038/s41598-022-14868-61912

Carbohydrate Mouth Rinse Mitigates Mental Fatigue Effects on Maximal Incremental Test Performance, but Not in Cortical Alterations

Detrimental mental fatigue effects on exercise performance have been documented in constant workload and time trial exercises, but effects on a maximal incremental test (MIT) remain poorly investigated. Mental fatigue-reduced exercise performance is related to an increased effort sensation, likely due to a reduced prefrontal cortex (PFC) activation and inhibited spontaneous behavior. Interestingly, only a few studies verified if centrally active compounds may mitigate such effects. For example, carbohydrate (CHO) mouth rinse potentiates exercise performance and reduces effort sensation, likely through its effects on PFC activation. However, it is unknown if this centrally mediated effect of CHO mouth rinse may mitigate mental fatigue-reduced exercise performance. After a proof-of-principle study, showing a mental fatigue-reduced MIT performance, we observed that CHO mouth rinse mitigated MIT performance reductions in mentally fatigued cyclists, regardless of PFC alterations. When compared to placebo, mentally fatigued cyclists improved MIT performance by 2.24–2.33 when rinsing their mouth with CHO during MIT. However, PFC and motor cortex activation during MIT in both CHO and placebo mouth rinses were greater than in mental fatigue. Results showed that CHO mouth rinse mitigated the mental fatigue-reduced MIT performance, but challenged the role of CHO mouth rinse on PFC and motor cortex activation

The analysis of COP and joint position sense in university soccer players with and without ankle instability

O objetivo do estudo foi comparar o comportamento do COP e do sentido de posição articular passivo em indivíduos com e sem instabilidade de tornozelo, e correlacionar as variáveis de COP e sentido de posição articular passivo. Participaram 20 indivíduos, divididos em dois grupos: grupo estável (GE) e grupo instável (GI). A avaliação do COP foi feita com o teste de apoio unipodal, com olhos abertos e fechados sobre uma plataforma de força. O teste de reposicionamento articular passivo foi realizado com os olhos vendados. O tornozelo foi posicionado em um ângulo alvo (10° e 20°) e o dinamômetro movia passivamente o tornozelo, então os participantes eram instruídos a apertar o botão para parar o movimento quando sentissem que o tornozelo estava no ângulo alvo, obtendo assim o erro angular absoluto (EAA). Foram obtidas as variáveis: deslocamento total (DT); desvio padrão ântero-posterior (DPap) e médio-lateral (DPml); velocidade média total (VMT); velocidade média ântero-posterior (VMap) e médio-lateral (VMml). A comparação entre dados que apresentaram distribuição normal foi feita com o teste t de Student, enquanto que para DT e DPml foi utilizado o teste de Mann-Whitney. Da mesma forma, foram usados os testes de Pearson e Spearman para correlacionar as variáveis. Foi adotado α < 0,05. Houve diferença entre EAA-10° (p < 0,05). Foram encontradas fortes correlações entre: EAA-10° e VMT (p < 0,01 r = −0,867); EAA-10° e VMap (p < 0,01 r = −0,854); EAA-10° e VMml (p < 0,01 r = −0,771), na condição olhos abertos, e EAA-10° e DT (p < 0,05 r = −0,666); EAA-10° e DPap (p < 0,05 r = −0,685) e EAA-10° e VMml (p < 0,05 r = −0,766) na condição olhos fechados. Entorses de tornozelo prejudicam o sentido de posição, sem afetar o equilíbrio.The aim of the study was to compare the behavior of COP and passive ankle position sense in subjects with and without functional ankle instability. Took part in this study 20 subjects, divided into two groups: stable group (SG) and unstable group (UG). The COP evaluation was made with the single-leg balance test, with eyes opened and closed, on a force plate. The passive ankle position sense test was performed with subjects blindfolded. The ankle was positioned in a target angle (10° and 20°) and the dynamometer moved passively the ankle, then the subjects were instructed to push the stop button when they feel that the ankle was on the target angle, obtaining the absolute angular error (AAE). The following variables were obtained: total displacement (TD); antero-posterior (SDap) and medio-lateral standard deviation (SDml); total mean velocity (TMV); antero-posterior (MVap) and medio-lateral mean velocity (MVml). The comparison between the data with normal distribution was made with the Student's t test, while to the TD and SDml was used the Mann-Whitney test. The correlations were performed with the Pearson and Spearman tests. We adopted α < 0.05. We observed difference between AAE-10° (p < 0.05). Strong correlations were found between: AAE-10° and TMV (p < 0.01 r = −0.867); AAE-10° and MVap (p < 0.01 r = −0.854); AAE-10° and MVml (p < 0.01 r = −0.771), with eyes opened, and AAE-10° and TD (p < 0.05 r = −0.666); AAE-10° and SDap (p < 0.05 r = −0,685) and AAE-10° and MVml (p < 0.05 r= −0.766) with eyes closed. Ankle sprains harm the joint position sense without affecting the balance

LABORATÓRIO DE BIOMECÂNICA DO PORTO: ENSINO, INVESTIGAÇÃO E SERVIÇOS À COMUNIDADE

Porto Biomechanics Laboratory is a technological centre of the University of Porto dedicated to teaching, scientific and technological research, innovation, to provide specialized technical services and transference of knowledge and technology (product development) in Biomechanics (human and animal) of ergonomic, clinical, sports or biomimetic interest (e.g. design, computer animation and model development). LABIOMEP-UP mission is to catalyse the growth potential and competitive edge of University of Porto in all domains directly or indirectly related to Biomechanics, including the interaction with industry.El Laboratorio de Biomecánica de Porto es un centro tecnológico de la Universidad de Porto dedicado a la docencia, la investigación científica y tecnológica, la innovación, proporcionar servicios técnicos especializados y transferencia de conocimiento y tecnología (desarrollo de productos) en Biomecánica (humana y animal) de ergonomía, clínica, deportiva, o interés biomimético (por ejemplo, diseño, animación por computadora y desarrollo de modelos). La misión de LABIOMEP-UP es catalizar el potencial de crecimiento y la ventaja competitiva de la Universidad de Oporto en todos los dominios relacionados directa o indirectamente con la biomecánica, incluida la interacción con la industria.O Laboratório de Biomecânica do Porto (LABIOMEP-UP) é um centro de competências da Universidade do Porto dedicado ao ensino, investigação científica e tecnológica, inovação, prestação de serviços técnicos especializados e transferência de conhecimento e tecnologia em Biomecânica (humana e animal) de interesse ergonómico, clínico, desportivo ou biomimético (ex: design, animação computacional e desenvolvimento de modelos). A missão do LABIOMEP-UP é catalisar o potencial de crescimento e vantagem competitiva da Universidade do Porto em todos os domínios direta ou indiretamente relacionados com a Biomecânica, incluindo a interação com o tecido industrial e comercial

LABORATÓRIO DE BIOMECÂNICA DO PORTO: ENSINO, INVESTIGAÇÃO E SERVIÇOS À COMUNIDADE

Porto Biomechanics Laboratory is a technological centre of the University of Porto dedicated to teaching, scientific and technological research, innovation, to provide specialized technical services and transference of knowledge and technology (product development) in Biomechanics (human and animal) of ergonomic, clinical, sports or biomimetic interest (e.g. design, computer animation and model development). LABIOMEP-UP mission is to catalyse the growth potential and competitive edge of University of Porto in all domains directly or indirectly related to Biomechanics, including the interaction with industry.El Laboratorio de Biomecánica de Porto es un centro tecnológico de la Universidad de Porto dedicado a la docencia, la investigación científica y tecnológica, la innovación, proporcionar servicios técnicos especializados y transferencia de conocimiento y tecnología (desarrollo de productos) en Biomecánica (humana y animal) de ergonomía, clínica, deportiva, o interés biomimético (por ejemplo, diseño, animación por computadora y desarrollo de modelos). La misión de LABIOMEP-UP es catalizar el potencial de crecimiento y la ventaja competitiva de la Universidad de Oporto en todos los dominios relacionados directa o indirectamente con la biomecánica, incluida la interacción con la industria.O Laboratório de Biomecânica do Porto (LABIOMEP-UP) é um centro de competências da Universidade do Porto dedicado ao ensino, investigação científica e tecnológica, inovação, prestação de serviços técnicos especializados e transferência de conhecimento e tecnologia em Biomecânica (humana e animal) de interesse ergonómico, clínico, desportivo ou biomimético (ex: design, animação computacional e desenvolvimento de modelos). A missão do LABIOMEP-UP é catalisar o potencial de crescimento e vantagem competitiva da Universidade do Porto em todos os domínios direta ou indiretamente relacionados com a Biomecânica, incluindo a interação com o tecido industrial e comercial

Indicadores biomecânicos do karate de alto nível

Karate is a sport widely practiced around the world, with its number of practitioners constantly growing. His techniques involve complex movements of upper and lower limbs and require the performer speed, agility, technique, precision and efficient decision making. Due to expansion in the number of practitioners and competitions with demanding technical level increasing, its practitioners as well as their trainers and technicians have expressed the need for scientific support accordingly. Therefore, the aim of this study is to determine what biomechanical indicators differentiate the performance of athletes of different competitive levels in Karate while performing the Gyaku Tsuki and Mae Geri strokes. To this end, the following specific objectives were established: (1) analyze dynamometric parameters during flexion and extension isometric and isokinetic of the shoulder, elbow, knee and hip joints of athletes from different competitive levels in karate; (2) analyze temporal parameters of the execution of Gyaku Tsuki and Mae Geri strokes in athletes of different competitive levels in karate; (3) analyze dynamic parameters in the execution of Gyaku Tsuki and Mae Geri strokes in athletes of different levels of experience in karate; (4) analyze coordinative parameters of the execution of Gyaku Tsuki and Mae Geri strokes and your variability in athletes of different levels of experience in karate; (5) analyze the relationship of electromyographic parameters of muscles involved in implementing of Gyaku Tsuki and Mae Geri strokes in athletes of different competitive levels in karate. For each proposed objective is presented a paper, in which were evaluated 14 male volunteers, aged 18 to 35, competitive practitioners of Karate, Black Belts, divided into two subgroups: Elite Group (GE), 07 individuals, competitors at national or international level; and Sub-elite Group (GSE), 07 individuals, competitors at regional or state level. During the ...O Karatê é um esporte amplamente praticado ao redor do mundo, com seu número de praticantes em constante crescimento. Suas técnicas implicam em movimentos complexos de membros inferiores e superiores e que exigem do executante velocidade, agilidade, técnica, precisão e eficiente tomada de decisão. Devido a expansão no número de praticantes e de competições com exigência de nível técnico cada vez maior, seus praticantes assim como seus preparadores físicos e técnicos têm manifestado a necessidade de suporte científico na mesma proporção. Diante disto, o objetivo geral deste estudo é de determinar quais indicadores biomecânicos diferenciam o desempenho de atletas de diferentes níveis competitivos no Karatê durante a realização dos golpes Gyaku Tsuki e Mae Geri. Para tanto, foram estabelecidos os seguintes objetivos específicos: (1) analisar parâmetros dinamométricos durante a flexão e extensão isométrica e isocinética das articulações do ombro, cotovelo, joelho e quadril de atletas de diferentes níveis competitivos no karatê; (2) analisar parâmetros temporais da execução dos golpes Gyaku Tsuki e Mae Geri em atletas de diferentes níveis competitivos no karatê; (3) analisar parâmetros dinâmicos na execução dos golpes Gyaku Tsuki e Mae Geri em atletas de diferentes níveis de experiência no karatê; (4) analisar parâmetros coordenativos da execução dos golpes Gyaku Tsuki e Mae Geri e sua variabilidade em atletas de diferentes níveis de experiência no karatê; (5) analisar o relacionamento de parâmetros eletromiográficos de músculos envolvidos na execução dos golpes Gyaku Tsuki e Mae Geri em atletas de diferentes níveis competitivos no karatê. Para cada objetivo proposto é apresentado um artigo, nos quais foram avaliados 14 voluntários do gênero masculino, faixa etária de 18 a 35 anos, praticantes competitivos de Karatê, Faixas Pretas, divididos em 2 subgrupos: Grupo Elite (GE), 07...

Characteristics of the handgrip of the high level judokas

The objective of this study was to analyze the characteristics of grip in Judo. The study included 08 athletes with a degree of black belt in Judo, male, over 18 years, competing at the international level and who seek to place the 2012 London Olympics. To characterize the types of grip that make up the judo technique to grab the opponent, there were shots of fighting athletes in training, was used a spreadsheet where identifies the type of grip on the judogi specific locations and also in relation to specific by hand. As for the quantification of the kind of grip on fighting, videos of international competitions were analyzed, was used a spreadsheet that quantifies the number of grips on each site judogi the opponent, so that later was made an indirect relationship with the spreadsheet data characterization and thus to obtain a quantification of the types of grip in international fights. For the measurement of handgrip dynamometers were used developed by Instrumentation Laboratory (LABIN/CEFID/UDESC). The handgrip strength was measured for 30 seconds, three times in the dominant hand and three times in the non dominant hand with measures interspersed in his hands, sitting, adapted from the American Society of Hand Therapists (ASHT). Was analyzed the following parameters of the Force vs. Time curve of the grip types identified, maximum force (FMAX), reaction time (TREACT), time to maximum force (TFMAX), growth rate of force (TXCRESC) and the Index fall of force (IQ). Among the results cited that were identified in all three ways to grip used by judokas: Full Palmar, digit-palmar and a third consisting of an association between Digit-palmar and lateral pinch. To check the difference in the use of forms of grip, between the dominant and non dominant hand was used Wilcoxon test where differences were found in the use of all forms of grip, in his hands. To see if there was a difference between the parameters of force-time curve of the ways to grip seen between the dominant and non dominant hand was used T test for paired data in the parametric data and Wilcoxon test for non-parametric, difference lying only in the Index fall of force of the Full palmar. To correlate the use of a way to grip with the behavior of their parameters from force-time curve was used Pearson's correlation test for parametric data and Spearman correlation test for non-parametric, and correlation was found in four cases. Two correlations were positive: use of Digit-palmar grip and the maximum force Full Palmar in the dominant hand and Full Palmar grip use and time to the maximum force in the non dominant hand. The other two correlations are presented as negative: Full Palmar grip use and maximum force Palmar grip in the dominant hand and the use of the association of Digit-palmar and lateral pinch and reaction time of lateral pinch grip on non dominant hand. The data obtained from the study demonstrate the difference function and use of the hands of judo, and how the usage is correlated with the parameters of force-time curve, explaining a specific conditioning.O objetivo deste trabalho foi analisar as características da preensão manual no Judô. Participaram do estudo 08 praticantes de judô com graduação de faixa preta, do sexo masculino, maiores de 18 anos, que competem em nível internacional e que buscam vaga para a Olimpíada de Londres 2012. Para a caracterização dos tipos de preensão que compõem a pegada do Judô, foram realizadas filmagens dos atletas desempenhando pegadas no treinamento, utilizou-se uma planilha onde se identifica o tipo de preensão em locais específicos do judogui e com especificidade também em relação à mão. Já para a quantificação do tipo de preensão em lutas, vídeos de competições internacionais foram analisados, utilizou-se uma planilha que quantifica o número de pegas em cada local do judogui do adversário, para que posteriormente fosse realizada uma relação indireta com os dados da planilha de caracterização e assim obtivesse-se uma quantificação dos tipos de preensão em lutas internacionais. Para a mensuração da preensão manual foram utilizados dinamômetros desenvolvidos pelo Laboratório de Instrumentação (LABIN/CEFID/UDESC). A Força de preensão manual foi avaliada durante 30 segundos, três vezes na mão dominante e três vezes na mão não dominante com mediadas intercaladas entre as mãos, na posição sentada, adaptada da Sociedade Americana de Terapeutas da Mão (ASHT). Foram analisados os seguintes parâmetros da curva de Força x Tempo dos tipos de pega identificados, Força máxima (FMAX), Tempo de reação (TREACT), o Tempo até a força máxima (TFMAX), Taxa de crescimento da força (TXCRESC) e o Índice de queda da força (IQ). Entre os resultados cita-se que foram identificadas no total três formas de pega utilizadas pelos judocas: Palmar Plena, Dígito-palmar e uma terceira que consiste em uma associação entre Dígito-palmar e Pinça Lateral. Para verificar a diferença no uso das formas de pega, entre a mão dominante e não dominante foi utilizado o Teste de Wilcoxon onde foi encontrada diferença no uso de todas as formas de pega, entre as mãos. Para verificar se existia diferença entre os parâmetros da curva força x tempo das formas de pega identificadas entre a mão dominante e não dominante foi utilizado Teste T para dados pareados nos dados paramétricos e Teste de Wilcoxon para os não paramétricos, encontrando diferença somente no Índice de queda da força de preensão Palmar Plena. Para correlacionar o uso de uma forma de pega e o comportamento de seus respectivos parâmetros da curva força x tempo foi utilizado o Teste de Correlação de Pearson para os dados paramétricos e o Teste de Correlação de Spearman para os não paramétricos, sendo que foi encontrada correlação em quatro casos. Duas correlações obtiveram resultado positivo: uso de preensão Dígito-palmar e a força máxima Palmar Plena na mão dominante e o uso da preensão Palmar Plena e o tempo até a força máxima na mão não dominante. As outras duas correlações se apresentaram como negativas: uso da preensão Palmar Plena e a força máxima de preensão Palmar na mão dominante e uso da associação Dígito-palmar e Pinça Lateral e o tempo de reação da preensão de Pinça Lateral na mão não dominante. Os dados obtidos com a pesquisa demonstram a diferença de função e de utilização das mãos dos judocas, bem como de que forma a utilização se correlaciona com parâmetros da curva de força x tempo, explicando um condicionamento específico.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Fingers movements control system based on artificial neural network model

Surface electromyographic (sEMG) signal is used in the various fields of applications where the need exists to measure the activity of body muscles, such as brain-computer interfaces, game industry, medical engineering, and other practical spheres. Even more, the use of sEMG signal in the field of active prosthesis industry has become traditional for many years. However, despite the fact that the question of using it in the field of fingers prostheses is still open, in general, the sEMG signal required multichannel measuring devices or massive, voluminous equipment for precise recognition of hands or fingers movement. That is decreasing the possible portability and convenience of prostheses and as a consequence is increasing their final price. In this paper we propose a method of organizing the controlling and measuring unit of the prosthetic device based on artificial neural network (ANN) model and one-channel microcontroller based sEMG measuring system. The proposed ANN model works with only 4 input time-domain features of sEMG signal and provides an accuracy of 95.52% for classification of 6 different types of finger movements that makes it a good solution for next implementation in the system of prosthetic fingers or wrist devices