One-Repetition Maximum and Repetitions to Failure at Submaximal Intensity in Eccentric-Only, Concentric-Only, and...

Shibata, K, Yamaguchi, T, Shimamori, K, Yamazaki, Y, Takizawa, K, and Nosaka, K. One-repetition maximum and repetitions to failure at submaximal intensity in eccentric-only, concentric-only, and conventional arm curl, bench press, and back squat exercises. J Strength Cond Res 39(5): 515-522, 2025-The present study compared eccentric-only (ECC-only), concentric-only (CON-only), and eccentric-concentric (ECC-CON) arm curl (AC), bench press (BP), and back squat (BSQ) exercises for 1 repetition maximum (1RM) and repetitions to failure (RF) to delineate characteristics of ECC-only exercises. Twelve resistance-trained young men participated in 7 sessions. In session 1, 1RM of ECC-CON was determined for AC, BP, and BSQ. In session 2, ECC-CON 1RM for the 3 exercises were reassessed, and RF of ECC-CON at 80% of ECC-CON 1RM load was examined for the exercises. In sessions 3 and 4, RF of ECC-only and CON-only at 80% of ECC-CON 1RM load was determined. In session 5, ECC-only 1RM and CON-only 1RM were assessed for the exercises. In sessions 6 and 7, RF of ECC-only and CON-only at 80% of respective 1RM load was measured. The 1RM was greater (p < 0.01) for ECC-only (AC: 19.3 ± 3.6 kg, BP: 103.3 ± 18.2 kg, BSQ: 141.3 ± 17.5 kg) than for CON-only (AC: 14.6 ± 2.9 kg, BP: 82.3 ± 16.2 kg, BSQ: 113.8 ± 14.5 kg) and for ECC-CON (AC: 14.3 ± 3.2 kg, BP: 87.1 ± 16.2 kg, BSQ: 119.2 ± 16.1 kg) with a significant difference between CON-only and ECC-CON for BP only. The RF was greater (p < 0.01) in ECC-only than in CON-only and ECC-CON at 80% of ECC-CON 1RM and respective 80% 1RM load for all 3 exercises (e.g., BP at 80% of respective 1RM load, ECC-only: 14.5 ± 4.6, CON-only: 10.0 ± 3.3, ECC-CON: 10.3 ± 2.1 repetitions). These results suggest that greater loads can be handled in ECC-only with less fatigue than others, and this provides advantages for eccentric-only resistance exercises.