The Effects of Amino Acid Supplementation on Hormonal Responses to Resistance Training Overreaching
Authors
William J. Kraemer, University of Connecticut
Nicholas A. Ratamess, College of New Jersey
Jeff S. Volek, University of Connecticut
Keijo Hakkinen, University of Jyväskylä
Martyn R. Rubin, University of Connecticut
Duncan N. French, University of Connecticut
Ana L. Gomez, University of Connecticut
Michael R. McGuigan, Edith Cowan University
Timothy P. Scheett, University of Southern Mississippi
Robert U. Newton, Edith Cowan UniversityFollow
Barry A. Spiering, University of Connecticut
Mikel Izquierdo, Government of Navarra
Francesco S. Dioguardi, University of Milan and IRCCS
Document Type
Journal Article
Publisher
Elsevier
Faculty
Faculty of Computing, Health and Science
School
School of Exercise, Biomedical and Health Science
RAS ID
4177
Abstract
The purpose of this investigation was to examine the effects of amino acid supplementation on muscular performance and resting hormone concentrations during resistance training overreaching. Seventeen resistance-trained men were randomly assigned to either an amino acid (AA) or a placebo (P) group and underwent 4 weeks of total-body resistance training designed to induce a state of overreaching. The protocol consisted of two 2-week phases (phase 1, 3 sets of 8 exercises performed for 8-12 repetitions; phase 2, 5 sets of 5 exercises performed for 3-5 repetitions). Muscle strength and resting blood samples were determined before (T1) and at the end of each training week (T2-T5). One-repetition maximum squat and bench press decreased at T2 in the P group but not in the AA group; both groups showed similar increases in strength at T3 to T5. Significant elevations in serum creatine kinase and uric acid were observed at T2 in the P group; the elevation in creatine kinase correlated highly to reductions in 1-repetition maximum squat (r = −0.67, r2 = 0.45). Significant elevations in serum sex hormone–binding globulin were observed during overreaching in the P group from T2 to T5; this response was abolished in the AA group. Significant reductions in total testosterone were observed in the P group at T4 compared with T1, and total testosterone values were higher for the AA group than for the P group from T2 to T4. Serum 22-kd growth hormone concentrations were elevated at T2 to T5 in P group only. No differences were observed in resting cortisol and insulinlike growth factor 1. Hemoglobin concentrations were significantly reduced at T2 to T5 in the P group. These results indicate that the initial impact of high-volume resistance training is muscle strength reduction and hormonal/biochemical alterations. It appears that amino acid supplementation is effective for attenuating muscle strength loss during initial high-volume stress, possibly by reducing muscle damage by maintaining an anabolic environment.
DOI
10.1016/j.metabol.2005.08.023
Comments
Kraemer, W., Ratamess, N., Volek, J., Hakkinen, K., Rubin, M., French, D., Gomez, A., Mcguigan, M. R., Scheett, T., Newton, R. , Spiering, B., Izquierdo, M., & Dioguardi, F. (2006). The effects of amino acid supplementation on hormonal responses to resistance training overreaching. Metabolism, 55(3), 282-291. Available here