Effects of Eurycoma Longifolia Jack supplementation on eccentric leg press exercise-induced muscle damage in rugby players
Abstract
Eurycoma longifolia Jack (ELJ) is a herbal plant that has androgenic and antioxidant effects. We investigated the short-term effect of ELJ supplementation on muscle damage induced by eccentric exercise. Eighteen young (19–25 years), well-trained rugby 7s players were assigned to an ELJ or a placebo (PLA) group (n = 9/group). Each participant took four 100-mg capsules a day for seven days prior to performing a leg press eccentric exercise to failure in a double-blind fashion. Peak force, peak power and jump height in countermovement jump (CMJ), drop jump reactive strength index (RSI), muscle soreness assessed by a 100-mm visual analogue scale, plasma creatine kinase (CK) activity, and salivary hormones were measured at 24 h before and 0.5, 24, 48, 72, and 96 h after the exercise. Changes in the variables over time were compared between the groups by two-factor mixed-design ANOVA. The number of eccentric contractions performed was similar (P = 0.984) between the ELJ (21 ± 5) and PLA groups (21 ± 5). Salivary testosterone and cortisol concentrations did not change (P > 0.05) after the supplementation for both groups. CMJ peak power (-9.4 ± 5.6%) and height (-10.6 ± 4.9%), and RSI (-15.2 ± 16.2%) decreased at 24 h after exercise (P < 0.05), and muscle soreness (peak: 89 ±10 mm) and plasma CK activity (peak: 739 ± 420 IU/L) increased after exercise (P < 0.05) without significant differences between groups. These results showed that 7-day ELJ supplementation prior to the leg press eccentric exercise had no significant effects on hormones, performance and muscle damage markers for the athletes.
RAS ID
60208
Document Type
Journal Article
Date of Publication
1-1-2023
Volume
40
Issue
3
Funding Information
The Institut Sukan Negara
School
Centre for Human Performance / School of Medical and Health Sciences
Copyright
free_to_read
Publisher
Institute of Sport
Comments
Zakaria, A. Z., Washif, J. A., Lim, B. H., & Nosaka, K. (2023). Effects of eurycoma longifolia jack supplementation on eccentric leg press exercise-induced muscle damage in rugby players. Biology of Sport, 40(3), 691-697. https://doi.org/10.5114/biolsport.2023.119290