Comparison Between Bilateral and Unilateral Leg-Press Resistance Exercise Training for Their Effects on Muscle...

Sato, S, Nosaka, K, Murakami, Y, Kasahara, K, Yosida, R, and Nakamura, M. Comparison between bilateral and unilateral leg-press resistance exercise training for their effects on muscle strength and jump performance. J Strength Cond Res 40(9): 1035-1042, 2026-This study compared the effects of unilateral and bilateral leg-press eccentric-accentuated resistance training on lower-limb strength and jump performance. Twenty-eight resistance-untrained young men were assigned to either a bilateral (BG, n = 14) or unilateral training group (UG, n = 14) and performed a leg-press resistance exercise consisting of 3 sets of 10 (3-s eccentric, 1-s concentric) contractions in a session, twice weekly for 8 weeks. The UG completed the leg-press exercise for each leg separately within a session, and the BG trained both legs together. The training intensity increased from 30 to 120% of the pretraining 1 repetition maximum (1RM) strength. Changes in bilateral and unilateral leg press 1RM strength, maximal voluntary contraction (MVC) torque of knee extensors (KE) and flexors, squat (SJ), countermovement (CMJ), and drop jumps (DJ) were measured before and after training. The bilateral leg-press 1RM strength increased ( p < 0.05) similarly from pre- to post-training for BG (150.4 ± 18.7 to 170.0 ± 21.1 kg: 13.4 ± 9.3%) and UG (144.3 ± 17.8 to 165.4 ± 21.2 kg: 14.7 ± 7.1%). Likewise, MVC-isometric (BG:10.2 ± 7.6%, UG:12.4 ± 9.3%), MVC-concentric (11.5 ± 12.0%, 7.0 ± 8.1%), MVC-eccentric (10.7 ± 10.8%, 11.0 ± 7.5%) of the KEs, and SJ (14.0 ± 13.4%, 9.8 ± 13.0%), CMJ (9.6 ± 11.7%, 9.0 ± 8.7%), and DJ (14.2 ± 16.4%, 16.3 ± 19.4%) height increased ( p < 0.05) without significant differences between groups. However, the increase in unilateral 1RM strength was greater ( p < 0.01) for UG (22.7 ± 7.0%) than for BG (13.7 ± 8.3%). No significant ( p > 0.05) correlations were evident between changes in the muscle strength and jump height measures. These indicate that unilateral than bilateral eccentric-accentuated resistance training increased single-leg 1RM strength greater, probably because of training specificity, but no other measures changed differently between the unilateral and bilateral training.