Impact of different training protocols on muscle synergism in maximal and submaximal strength tests in bench press exercise

Objective: This study analyzed the activation of pectoralis major and triceps brachii muscles in strength tests in bench press after 10 weeks of training. Methods: Thirty-three untrained individuals were divided into two experimental and one-control groups. Protocols were matched by intensity (50-55% of one repetition maximum - 1RM), frequency (3 times a week), pause between sets (3 minutes), number of sets (3 to 4 sets), and time under tension in each set (36 seconds), but with different repetition number and duration (12 repetitions vs. 3seconds / 6repetitions vs. 6seconds). Results: In strength endurance test both experimental groups increased amplitude of Electromyography (EMG) signal in comparison to control group, but with no difference between them. Activation was higher for triceps brachii than for pectoralis major and thus the pectoralis major/triceps brachii activation ratio significantly decreased for both groups, but with no difference between them. In the 1RM and maximum voluntary isometric contraction tests, EMG signal amplitude, activation ratio and analysis of cross-correlation did not exhibited any changes when comparing the experimental and control groups. Conclusion: The results showed that the fact that the protocols used dynamic actions, as well as the same time under tension (TUT), and the differences between single and multiple repetition tests, determined the responses verified.