Effective number of maximal eccentric contractions in the early phase of twice-weekly training to increase muscle strength and thickness of the elbow flexors in untrained young adults
Author Identifier (ORCID)
Kazunori Nosaka: https://orcid.org/0000-0001-7373-4994
Abstract
Purpose: We previously reported that maximal voluntary contraction (MVC) strength increased more than 10% when one 3-s maximal eccentric contraction of the elbow flexors was performed five days a week for four weeks, but this was not observed when the frequency was reduced to twice a week. In the present study, we investigated whether MVC strength would increase when 5 or 15 maximal eccentric contractions were performed per session in twice-weekly training. Methods: Healthy young (19-23y) adults performed either 1 set of 5 (5 × 2 group, n = 12) or 3 sets of 5 (15 × 2 group, n = 12) maximal muscle actions 2 sessions/week for 4 weeks. Changes in maximal voluntary isometric (MVIC), concentric (MVCC), and eccentric contraction (MVEC) torque of the elbow flexors and muscle thickness of the biceps brachii and brachialis (MT) before and after the 4-week training were compared between groups. The changes were also compared to the 1 × 2 (1 contraction/session, 2 sessions/week) and 1 × 5 (1 contraction/session, 5 sessions/week) groups that were investigated in the previous studies. Results: The 5 × 2, 15 × 2 and 1 × 5 groups increased (p ≤ 0.05) MVIC (7.0 ± 5.9%, d = 0.21; 7.5 ± 10.4%, d = 0.23; 10.2 ± 6.4%, d = 0.33, respectively), MVCC (9.7 ± 6.6%, d = 0.27; 5.1 ± 5.9%, d = 0.22; 12.8 ± 9.6%, d = 0.43), and MVEC (8.4 ± 5.8%, d = 0.27; 8.7 ± 9.2%, d = 0.28; 12.2 ± 7.8%, d = 0.41), torque without a significant difference between groups. MT increased (p ≤ 0.05) similarly in the 5 × 2 (5.4 ± 4.4%, d = 0.37) and 15 × 2 (8.1 ± 6.2%, d = 0.50) groups, but not for the 1 × 2 and 1 × 5 groups. Conclusion: These results suggest that 5 maximal eccentric contractions per session could increase muscle strength and size of untrained adults in the twice-weekly training.
Document Type
Journal Article
Date of Publication
1-1-2025
Publication Title
European Journal of Applied Physiology
Publisher
Springer
School
School of Medical and Health Sciences
RAS ID
88128
Copyright
subscription content
Comments
Sato, S., Yoshida, R., Murakami, Y., Kasahara, K., Nosaka, K., & Nakamura, M. (2025). Effective number of maximal eccentric contractions in the early phase of twice-weekly training to increase muscle strength and thickness of the elbow flexors in untrained young adults. European Journal of Applied Physiology. Advance online publication. https://doi.org/10.1007/s00421-025-06023-6