Neither repetition duration nor number of muscle actions affect strength increases, body composition, muscle size, or fasted blood glucose in trained males and females

Abstract

A key variable within resistance training (RT) is that of repetition duration; the time (seconds; s) taken to perform the concentric and eccentric muscle actions of a repetition. Research has produced equivocal results with regards to strength and muscle mass increases whilst many studies have created parity in the number of repetitions though there has been a disparity in load used and time-under-load (TUL). The purpose of this study was to compare load, and TUL matched groups performing resistance exercise using differing repetition durations. Fifty-nine male and female participants were randomised in to 3 groups; 2s:4s (n=18), 10s:10s (n=20) and a group which performed a 30s eccentric, 30s concentric and 30s eccentric muscle actions (e.g. 1.5 repetitions; n=21). Participants were supervised in 1-on-1 RT sessions 2 d.wk-1 for 10 weeks. Outcomes were 10-repetition maximum (RM) and predicted 1RM for chest press, leg press and pull-down exercises, as well as body composition, upper arm and thigh muscle mass and fasted blood glucose. Analyses revealed significant increases in strength for all exercises but no between-group differences, and no statistically significant time course changes for the other variables. Repetition duration does not affect the increases in strength in trained participants where exercise is performed to momentary failure. Since time constraints and perceived difficulty are often cited barriers to exercise, it is important to recognise that the low-volume (single-set), machine-based protocol employed herein produced worthwhile strength increases in trained participants.

Effect of Repetition Duration—Total and in Different Muscle Actions—On the Development of Strength, Power, and Muscle Hypertrophy: A Systematic Review

“…On the other hand, some authors have investigated the effects of both CON and ECC in maximal dynamic strength. Pereira et al (48) and Pearson et al (47) found that the use of 4/0/1/0 and 3/0/1/0, respectively, induce greater improvements (+18-24%) than in the 1/0/1/0 control group, which is supported by studies developed by Carlson et al (4), Mike et al (43), and Neils et al (45). Therefore, the use of fast CON MAD with medium ECC MAD (3-4/0/1/0) could be a suitable strategy to be considered with trained subjects to retain elastic energy in the ECC to transfer it to the subsequent CON (39,42).…”

Intentionally Slow Concentric Velocity Resistance Exercise and Strength Adaptations: A Meta-Analysis

“…A second subgroup analysis was conducted to determine whether age influenced strength adaptations due to resistance training velocity. The number of effect sizes included in the young group was 20 from 19 studies (7,9,22,27,31,32,34,36,40,45,46,48,49,51,53,66,67,71,80), whereas 5 studies were included in the older group (6,17,39,44,75). Test of moderators found no significant subgroup effect between age groups, indicating no significant difference between subgroups (QM 5 0.09, p 5 0.77).…”

Entrenamiento con sobrecarga, duración de la repetición e hipertrofia: una revisión de la literatura

“…La evidencia actual (Carlson et al, 2018;Chaves et al, 2020;Shibata et al, 2018;Pereira et al, 2016) sugiere que un tiempo óptimo para obtener adaptaciones hipertróficas estaría en un rango de…”