Relationship between muscle strength and the curvature constant of the torque-duration relationship of the exercise

Author(s)

Natália de Menezes Bassan

• Document type: Doctoral Thesis
• Press: Rio Claro. 2018-11-30.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
• Defense date: 2018-10-31
• Advisor: Camila Coelho Greco

Abstract

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 '. (AU)

• FAPESP's process: 16/18017-5 - Relationship between muscle strength and the curvature constant of the torque-exercise duration relationship of the exercise
• Grantee: Natália de Menezes Bassan
• Support Opportunities: Scholarships in Brazil - Doctorate