Caracterização de variáveis cinemáticas e eletromiográficas da fase excêntrica no exercício supino reto em atletas paralímpicos

Abstract

The bench press is the exercise related to Weightlifting, which participated in the Paralympics for the first time in 1964 in Tokyo. This exercise is performed in two phases: the eccentric phase and the concentric phase. With evolution and many studies involving sports training through resistance exercises, much has been said about the importance of eccentric movement. Research involving these studies have found results in greater activation of muscles: the major pectoralis (MP), previous deltoid (PD) and triceps (T). Thus, the objective of this work was to characterize kinematic aspects along with the electromyographic aspects in three different periods of the eccentric phase of the bench press movement performed by athletes of paralympic weightlifting. The kinematic was used for the reconstruction of motion, allowing to find "subphases" in the eccentric phase. Through the kinematic it has been found the beginning of eccentric phase (TVi), the point where the speed of the eccentric phase reaches the largest negative peak value (TVdown) and the end of the eccentric phase (TVF). Three periods of bench press eccentric phase motion were analyzed: “complete movement” (TVi-TVf), TVi-TVdown e TVdown- TVf. From the electromyography, RMS, the Average Frequency (Fmed), Peak Frequency (Fpico), F50, F80 and Entropy values were calculated through a routine developed in Matlab software. The variables were calculated without the separation of gender, characterizing the movement of the athletes. Subsequently, athletes were separated into groups (male and female) and the mean and standard deviation of each variable were calculated for both, and from these data, the Wilcoxon nonparametric test was used to verify if there was a statistically significant difference between the parameters of the groups. In the first period and in the second period of the eccentric phase (TVi - TVdown) and (TVdown - TVf) respectively, the left PM, right PM, left DA and right DA muscles were the ones with the highest RMS value. In this item, the left MP was highlighted, where the test showed a significant difference in the analyzed group in all variables in the period "complete movement", except Fmed. In addition, a moderate correlation was found between the right TB and Fpico related to velocity in the eccentric phase in the period “complete movement”. These results can aid in the training of the eccentric phase, thus seeking the improvement of performance and better results in competitions.