Análise da atividade eletromiográfica, razão de ativação e percepção de esforço em sessões de treinamento no exercício supino reto guiado com o direcionamento do foco interno

Abstract

The manipulation of training variables in bodybuilding generates different demands on the individual, modifying parameters related to neuromuscular activity and perception of exertion. Strategies such as directing the focus of attention, although not related to the training variables, make it possible to change the mentioned parameters, modifying the demands generated in the individual. The objective of the study was to analyze the electromyographic activity (EMG) of the pectoralis major (PM) and triceps brachii (TB) muscles over 4 experimental sessions, presenting possible influences of verbal instruction to direct the internal focus on the PM muscle, compared to a session without instruction; as well as analyzing a cumulative effect on the EMG of the muscles throughout the sessions, in addition to analyzing the behavior of synergism, and the perceived exertion in the PM muscle, through the subjective perception of exertion (RPE). Thirteen strength-trained volunteers made up the sample, performing 5 experimental sessions in the bench press exercise on the guided bar. The first session consisted of performing maximum strength tests and familiarization procedures; the second in performing the session without instruction (SSI); and the next three sessions consisted of carrying out training with instruction for directing focus (SCI). Three statistical analyzes were performed to compose the results. For analysis of the EMG signal, the two-way ANOVA test with repeated measures was performed; for AR, a one-way ANOVA test with repeated measures was performed; and for RPE, Friedman's non-parametric test was performed. The results regarding the EMG did not show time x muscle interaction, demonstrating that there were no differences between the EMG activities of the muscles throughout the sessions; there was no main effect of muscles or time, demonstrating that there were no differences between the EMG of the muscles or along the sessions. There were no differences between the AR throughout the sessions, demonstrating that the synergism between the muscles did not change. Finally, no effects on PSE were returned, demonstrating that the effort in the PM muscle was the same throughout the sessions. The results demonstrated that the verbal instruction to direct the focus of internal attention to the PM muscle did not result in changes in the EMG, RA or PSE activity of the analyzed muscles.