Comparison Between Eccentric-Concentric and Eccentric-Only Dumbbell Arm Curl Exercise for the Number of Repetitions to Failure Over Five Sets

Shibata, K, Yamaguchi, T, Takizawa, K, and Nosaka, K. Comparison between eccentric-concentric and eccentric-only (ECC-only) dumbbell arm curl exercise for the number of repetitions to failure over five sets. J Strength Cond Res XX(X): 000–000, 2026—We compared eccentric-concentric (ECC-CON) and ECC-only dumbbell arm curl exercises for the number of repetitions to failure (RF) over 5 sets with 1- and 3-minute rest between sets. Twelve healthy male university students participated in 3 sessions. In session 1, one-repetition maximum (1-RM) of ECC-CON for one arm and ECC-only for the other arm was assessed. In sessions 2 and 3, the number of RF over 5 sets of ECC-CON and ECC-only at 80% of respective 1-RM load until failure in each set was investigated. The rest interval between sets was 1-minute or 3-minute in a pseudo-randomized order in the 2 sessions. The number of RF in ECC-only (17.5 ± 7.1 for 1-minute, 18.4 ± 7.9 for 3-minute rest) was greater ( p < 0.01) than that in ECC-CON (9.8 ± 2.0, 10.3 ± 2.2) in the first set. The number of RF decreased greater ( p < 0.01) for ECC-only (−13.1 ± 6.4, −13.9 ± 6.4) than ECC-CON (−6.2 ± 2.1, −3.8 ± 1.7) from the first to the second set. The number of RF was smaller ( p < 0.01) for ECC-only than ECC-CON in the third to the fifth sets in 3-minute rest condition (e.g., 3.2 ± 1.0 vs. 0.8 ± 1.3 in the fifth set) and was greater ( p < 0.01) in 3-minute than in 1-minute rest condition for ECC-CON alone (e.g., 3.2 ± 1.0 vs. 1.3 ± 1.0 in the fifth set). These results suggest that the less fatigable characteristics in ECC-only were limited to the first set, and ECC-only induced greater decrease in the number of RF over sets. Prolonging the rest interval between sets did not increase the number of RF in ECC-only.