The effects of amino acid supplementation on hormonal responses to resistance training overreaching

Kraemer, William J.; Ratamess, Nicholas A.; Volek, Jeff S.; Häkkinen, Keijo; Rubin, Martyn R.; French, Duncan N.; Gómez, Ana L.; McGuigan, Michael R.; Scheett, Timothy P.; Newton, Robert U.; Spiering, Barry A.; Izquierdo, Mikel; Dioguardi, Francesco S.

doi:10.1016/j.metabol.2005.08.023

« Previous Next »Metabolism - Clinical and Experimental
Volume 55, Issue 3 , Pages 282-291, March 2006

The effects of amino acid supplementation on hormonal responses to resistance training overreaching

William J. Kraemer
- Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT 06269-1110, USA
- Corresponding author. Tel.: +1 860 486 6892; fax: +1 860 486 6898.
Nicholas A. Ratamess
- Department of Health and Exercise Science, The College of New Jersey, Ewing, NJ 08628, USA
Jeff S. Volek
- Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT 06269-1110, USA
Keijo Häkkinen
- Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä 40014, Finland
Martyn R. Rubin
- Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT 06269-1110, USA
Duncan N. French
- Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT 06269-1110, USA
Ana L. Gómez
- Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT 06269-1110, USA
Michael R. McGuigan
- School of Biomedical and Sports Science, Edith Cowan University, Joondalup, WA 6027, Australia
Timothy P. Scheett
- Laboratory for Applied Physiology, The University of Southern Mississippi, Hattiesburg, MS 39406, USA
Robert U. Newton
- School of Biomedical and Sports Science, Edith Cowan University, Joondalup, WA 6027, Australia
Barry A. Spiering
- Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT 06269-1110, USA
Mikel Izquierdo
- Studies, Research and Sport Medicine Center, Government of Navarra, 31005 Pamplona (Navarra), Spain
Francesco S. Dioguardi
- Theoretic Medicine Center, University of Milan and IRCCS, Milan 9-20123, Italy

Received 15 June 2005; accepted 14 August 2005.

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.