Leucine Supplementation Has No Further Effect on Training-induced Muscle Adaptations

Author(s):Show less -

De Andrade, Isabel Thomazi ^{[1, 2]} ; Gualano, Bruno ^[1] ; Hevia-Larrain, Victoria ^[1] ; Neves-Junior, Juarez ^[1] ; Cajueiro, Monique ^[1] ; Jardim, Felipe ^[1] ; Gomes, Rodrigo Leite ^[1] ; Artioli, Guilherme Giannini ^[1] ; Phillips, Stuart M. ^[3] ; Campos-Ferraz, Patricia ^[2] ; Roschel, Hamilton ^[1]

Affiliation

^[1] Univ Sao Paulo, Appl Physiol & Nutr Res Grp, Sao Paulo, SP - Brazil

^[2] Univ Estadual Campinas, Fac Appl Sci, Sao Paulo, SP - Brazil

^[3] McMaster Univ, Dept Kinesiol, Hamilton, ON - Canada

• Document type: Journal article
• Source: MEDICINE AND SCIENCE IN SPORTS AND EXERCISE; v. 52, n. 8, p. 1809-1814, AUG 2020.
• Web of Science Citations: 0

Abstract

Introduction Several acute studies have suggested that leucine is a key amino acid to drive muscle protein synthesis. However, there are very few studies on the long-term effects of leucine supplementation on resistance training (RT)-induced gains in muscle mass and strength. We sought to determine the impact of 10 g of leucine on muscle mass and strength in response to RT in healthy young men. Methods Twenty-five, resistance-trained men (27 +/- 5 yr; 78.4 +/- 11.6 kg; 24.8 +/- 3.0 kg center dot m(-2)) consuming 1.8 +/- 0.4 g protein center dot kg(-1)center dot d(-1), were randomly assigned to receive 2 x 5 g center dot d(-1)supplementation of either free leucine (LEUn= 12) or alanine (PLAn= 13) while undergoing a supervised 12-wk, twice-weekly lower-limb RT program. One-repetition maximum (leg-press 1RM) and muscle cross-sectional area (mCSA) of thevastus lateraliswere determined before (PRE) and after (POST) the intervention. Additionally, three 24-h dietary recalls were also performed at PRE and POST. Results Protein intake was roughly double that of the RDA in both groups and remained unchanged across time with no differences detected between groups. Similar increases were observed between groups in leg-press 1RM (LEU, 19.0% +/- 9.4% and PLA, 21.0% +/- 10.4%,P =0.31) and mCSA (LEU, 8.0% +/- 5.6% and PLA, 8.4% +/- 5.1%,P= 0.77). Conclusions High-dose leucine supplementation did not enhance gains in muscle strength and mass after a 12-wk RT program in young resistance-trained males consuming adequate amounts of dietary protein. (AU)

• FAPESP's process: 16/22083-3 - The influence of the dietary protein source on long-term resistance training-induced changes
• Grantee: Victoria María de Los Ángeles Hevia Larraín
• Support Opportunities: Scholarships in Brazil - Master