Rodrigo César Ribeiro Diniz

Repetition duration influences ratings of perceived exertion.

This study investigated the effect of different repetition durations on ratings of perceived exertion (RPE) in active muscles (RPE-AM) and the overall body (RPE-O). 19 male volunteers (M age = 25.4 yr., SD = 3.5) performed strength training protocols with multiple sets matched by the number of sets and repetitions, intensity and rest interval but different repetition durations: 4 sec., 6 sec., or self-paced. Participants were asked to estimate their RPE-AM and RPE-O after each set. Training protocols with a 6-sec repetition duration produced distinct responses on RPE during and after performance compared to 4-sec. and self-paced durations. However, there were no significant differences between 4-sec. and self-paced durations.

Longer repetition duration increases muscle activation and blood lactate response in matched resistance training protocols

This study analyzed the effect of different repetition durations on electromyographic and blood lactate responses of the bench press exercise. Fifteen recreationally trained male volunteers completed two training protocols, matched for intensity (% one-repetition maximum; 1RM), number of sets, number of repetitions, and rest intervals. One of the protocols was performed with a repetition duration of 4 s (2 s concentric: 2 s eccentric; 2:2 protocol), whereas the second protocol had a repetition duration of 6 s (2 s concentric: 4 s eccentric; 2:4 protocol). The results showed higher normalized integrated electromyography (pectoralis major and triceps brachii) for the 2:4 protocol. Blood lactate concentration was also higher in the 2:4 protocol across all sets. These results show that adding 2 s to the eccentric action in matched training protocols increases muscle activation and blood lactate response, which reinforces the notion that increasing repetition duration is an alternative load progression in resistance training.