Relação entre a força muscular e a constante da curvatura da relação torque-duração do exercício
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Data
2018-10-31
Autores
Bassan, Natália de Menezes [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi analisar a relação da quantidade de trabalho acima do torque crítico (W’) com a força muscular, a partir da análise do efeito do treinamento unilateral de curta duração, influência da dominância e do nível de força. Participaram deste estudo indivíduos do gênero masculino com idades entre 20 e 35 anos que realizaram os seguintes procedimentos, em dias diferentes: 1) Familiarização ao dinamômetro isocinético, mensuração da espessura muscular (EM), eco intensidade (ECO) e antropometria ; 2) realização das medidas ultrassonográficas (EM e ECO), teste de contrações isométricas máximas para determinação da contração voluntária máxima (CVM) e um teste de contrações isométricas intermitentes, no modo all-out, para determinação do impulso acima do torque final (ITF), o qual representa o W’ e do torque final (TF), que representa o torque crítico, dos músculos extensores de joelho (EJ), ambos os testes foram realizados com a EMG de superfície no músculo vasto lateral (VL) para a análise da EMG e root mean square (RMS); 3) Foram realizados os mesmos testes do ítem 2 após 72 h após da última sessão de treinamento. O grupo de treinamento (GT) realizou um programa de treino de força de alta intensidade somente no membro dominante (MD) para os EJ com 2 sessões semanais de treinamento durante 3 semanas. O grupo controle (GC) não realizou o programa de treinamento. Antes e após o período de treinamento foram realizados os mesmos testes do item 2. Todos os testes foram realizados em dias diferentes com 72 h de recuperação entre um teste e outro no mesmo horário do dia (± 2 h) e em ordem randômica. O efeito do grupo, tempo e dominância na CVM, ITF, TF, iEMG, RMS, EM e ECO foi analisado pela Anova Three Way, complementada pelo teste de Bonferroni. A correlação entre a CVM e o ITF foi realizada por meio do teste de correlação de Pearson. O nível de significância adotado foi de p ≤ 0,05. Dessa maneira a CVM aumentou de maneira similar no MD e MND do GT. No GC não houve mudança significante para o MD e MND. A CVMpico mensurada durante o teste de all-out apresentou aumento similar no MD e MND do GT na. No GC não houve alteração significante nos valores, porém ao se analisar os valores de CVMmédia durante o allout, houve aumentou de maneira significante somente no MD do GT. Em relação ao ITF, ocorreu aumento significante somente no MD do GT, após o treinamento. Já para o TF não houve observada nenhuma alteração. A RMS e iEMG apresentou aumento similar no MD e no MND para o GT. Na EM ocorreu aumento significante apenas no MD do GT, enquanto a ECO não sofreu alteração em nenhum membro e grupo. Não foi observada mudança significante no GC para nenhuma variável. Foi encontrada correlação significante entre a CVM e o ITF antes do treinamento em ambos os membros. No GT antes do treinamento foi verificada correlação significante somente no MND, entretanto após o treinamento só no MD foi possível observar correlação. A variação da CVM e do ITF no membro dominante, antes e após o período de treinamento, no grupo treinado, não demonstrou correlação significante, porém foi observada correlação entre CVM e o ITF nos grupos com maior e menor nível de força muscular. Dessa maneira, sugere-se que o W’ parece sofrer influência somente de aspectos neurais relacionados ao membro treinado e ao tamanho do músculo, dado que foi encontrado correlações significativas entre a CVM e o ITF, no MD e MND e em indivíduos com diferentes níveis de força, sugerindo que quem possuir um maior nível de força também tem grande quantidade de ITF. Porém, faz-se necessária a realização de mais estudos para saber quais são os fatores e suas magnitudes que influenciam no W’.
The objective of this study was to analyze the relationship of the amount of work above the critical torque (W ') with the muscular strength, from the analysis of the effect of short duration unilateral training, influence of dominance and level of strength. Participants in this study were male subjects aged 20-35 years who performed the following procedures on different days: 1) Familiarization with the isokinetic dynamometer, muscle thickness (EM), echo intensity (ECO) and anthropometry; 2) ultrasound measurements (MS and ECHO), maximum isometric contraction test for determination of maximal voluntary contraction (MVC) and a test of intermittent isometric all-out contractions for impulse above end test-torque (IET), which represents the W' and the end test-torque (TF), which represents the critical torque of the knee extensor muscles (KE), all tests were performed with surface EMG in the vastus lateralis (VL) muscle for the analysis of EMG and root mean square (RMS), all tests were performed on both limbs; 3) the same tests of item 2 were performed after 72 hours of the last training session. The training group (GT) performed a high intensity strength training program in the dominant limb (DL) for the KE, 2 times per week for 3 weeks. The control group (CG) did not perform the training program. The first and last test period were the tests of item 2. All tests were performed at different times with 72 hours of recovery in one test and another at the same time of day (± 2 h) and in random order. The effect of the group, time and dominance on MVC, IET, ET, IEMG, RMS, MS and ECHO was analyzed by ANOVA THREE WAY, complemented by the Bonferroni test. The relationship between the MVC and the IET was performed using the Pearson correlation test. The level of significance was p ≤ 0.05. The results were, that MVC increased similarly in the DL and non-dominant limb of the GT. There was not a change on CG for DL and NDL. It was found an increase MVCpeak similar in DL and NDL of CG in. In the GC there was no significant change in the values. However, when was analyzed the values of MVCmean during all-out test, MVCmean significantly increased only in SG in DL. It was found a significant increase in IET on DL of the ST after the training. For the ET there was no significant change. RMS and iEMG showed a similar increase in DL and NDL for SG. There was a significant increase in MS in MD of SG. ECHO did not change in both groups and limbs. There was no significant in difference in CG. A moderate relationship was found between MVC and IET before training in both limbs. In SG, before training, a significant correlation was verified only in NDL. However, after the training only in the DL, it was possible to observe a correlation. MVC and IET variation in DL, before and after the training period, did not show a significant correlation in SG. Although, it was observed correlation between MVC and IET was in the groups with higher and lower levels of muscle strength. Thus, it is suggested that W 'seems to be influenced only by neural aspects related to the trained limb and to muscle size, since significant correlations were found between MVC and IET in DL and NDL and in individuals with different levels of strength, suggesting that those with a higher level of strength also have large amounts of IET. However, it is necessary to carry out further studies to determine the factors and their magnitudes that influence W '.
The objective of this study was to analyze the relationship of the amount of work above the critical torque (W ') with the muscular strength, from the analysis of the effect of short duration unilateral training, influence of dominance and level of strength. Participants in this study were male subjects aged 20-35 years who performed the following procedures on different days: 1) Familiarization with the isokinetic dynamometer, muscle thickness (EM), echo intensity (ECO) and anthropometry; 2) ultrasound measurements (MS and ECHO), maximum isometric contraction test for determination of maximal voluntary contraction (MVC) and a test of intermittent isometric all-out contractions for impulse above end test-torque (IET), which represents the W' and the end test-torque (TF), which represents the critical torque of the knee extensor muscles (KE), all tests were performed with surface EMG in the vastus lateralis (VL) muscle for the analysis of EMG and root mean square (RMS), all tests were performed on both limbs; 3) the same tests of item 2 were performed after 72 hours of the last training session. The training group (GT) performed a high intensity strength training program in the dominant limb (DL) for the KE, 2 times per week for 3 weeks. The control group (CG) did not perform the training program. The first and last test period were the tests of item 2. All tests were performed at different times with 72 hours of recovery in one test and another at the same time of day (± 2 h) and in random order. The effect of the group, time and dominance on MVC, IET, ET, IEMG, RMS, MS and ECHO was analyzed by ANOVA THREE WAY, complemented by the Bonferroni test. The relationship between the MVC and the IET was performed using the Pearson correlation test. The level of significance was p ≤ 0.05. The results were, that MVC increased similarly in the DL and non-dominant limb of the GT. There was not a change on CG for DL and NDL. It was found an increase MVCpeak similar in DL and NDL of CG in. In the GC there was no significant change in the values. However, when was analyzed the values of MVCmean during all-out test, MVCmean significantly increased only in SG in DL. It was found a significant increase in IET on DL of the ST after the training. For the ET there was no significant change. RMS and iEMG showed a similar increase in DL and NDL for SG. There was a significant increase in MS in MD of SG. ECHO did not change in both groups and limbs. There was no significant in difference in CG. A moderate relationship was found between MVC and IET before training in both limbs. In SG, before training, a significant correlation was verified only in NDL. However, after the training only in the DL, it was possible to observe a correlation. MVC and IET variation in DL, before and after the training period, did not show a significant correlation in SG. Although, it was observed correlation between MVC and IET was in the groups with higher and lower levels of muscle strength. Thus, it is suggested that W 'seems to be influenced only by neural aspects related to the trained limb and to muscle size, since significant correlations were found between MVC and IET in DL and NDL and in individuals with different levels of strength, suggesting that those with a higher level of strength also have large amounts of IET. However, it is necessary to carry out further studies to determine the factors and their magnitudes that influence W '.
Descrição
Palavras-chave
Força muscular, Dinamômetro isocinético, Exercício, Treinamento, Muscle strength, Isokinetic dynamometer, Fatigue, Exercise, Training