Variations in Repetition Duration and Repetition Numbers Influence Muscular Activation and Blood Lactate Response in Protocols Equalized by Time Under Tension

Abstract

The aim of this study was to investigate the impact of protocols equalized by the time under tension (TUT) but composed of different repetition durations and repetitions numbers on muscle activation and blood lactate concentration. Twenty-two males with previous experience in resistance training performed 2 training protocols (A and B) with the Smith machine bench press exercise, both with 3 sets, 3 minutes' rest, and 60% of 1 repetition maximum (1RM). Protocol A consisted of 6 repetitions with a 6-second repetition duration for each repetition, whereas in Protocol B the subjects performed 12 repetitions with a 3-second repetition duration for each repetition. Muscular activation was measured in the anterior deltoid, pectoralis major, and triceps brachii muscles while performing the 2 protocols, and the normalized root mean square of the electromyographic signal (EMGRMS) was calculated for each set. Blood lactate concentrations were measured during and until 12 minutes after the completion of each protocol. The results showed that the EMGRMS of all muscles increased during the sets and was higher in Protocol B when compared with Protocol A. Likewise, blood lactate concentrations also increased throughout the sets and were higher in Protocol B both during and after the completion of each training session. The data obtained in this study show that training protocols conducted with the same TUT, but with different configurations, produce distinct neuromuscular and metabolic responses so that performing higher repetition numbers with shorter repetition durations might be a more appropriate strategy to increase muscle activation and blood lactate concentration.

Determination and comparison of time under tension required to perform 8, 10 and 12-RM loads in the bench press exercise

“…Thus, the intensity can also be characterized by the total time of tension under a period of time [17]. Therefore, in the implementation of one or more training RM, there is a certain interval of time covered by the production of muscle strength, which is the time under tension (TUT).…”

“…The results showed that different times under tension significantly alter the muscular response. However, Lacerda et al [17] found that the same TUT can also present different results in the electromyographic activity carried out at different running speeds and consequently different number of repetitions. Thus, these studies point to the need to determine the average TUT of exercise and its influence on muscle responses.…”

Acute neuromuscular response during eccentric overload protocol by using a mechanical device to increase the load

“…For the EO protocol, the mechanical resistance during the ECC action was higher than the resistance during the CON action; however, the CO protocol showed the same resistance during both contractions. The duration of the repetition, which is a factor that affects neuromuscular activation 19 , was used as a control variable. The total duration of the repetition was 6 s (controlled with a metronome [Metronome Plus®]): 2 s for the CON action, 1 s for the isometric (ISO) muscle action (which was necessary to expand the mechanical device), 2 s for the ECC action, and finally 1 s for placing the mechanical device at the start position (before starting another repetition).…”

Avaliação e controlo do treino: Informação ou ruído?

“…Por exemplo, qual o tempo sob tensão que foi necessário para realizar 1RM? É sabido que o tempo sob tensão modifica a expressão de força e deveria ser analisado nas avaliações de força (10,20) . Adicionalmente, qual a força produzida no início do movimento?…”