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The effects of amino acid supplementation on hormonal responses to resistance training overreaching.
- Source :
- Metabolism: Clinical & Experimental; Mar2006, Vol. 55 Issue 3, p282-291, 10p
- Publication Year :
- 2006
-
Abstract
- 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, r <superscript>2</superscript> = 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. [Copyright &y& Elsevier]
- Subjects :
- AMINO acids
MUSCLE strength
PHYSICAL fitness
PEPTIDES
Subjects
Details
- Language :
- English
- ISSN :
- 00260495
- Volume :
- 55
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Metabolism: Clinical & Experimental
- Publication Type :
- Academic Journal
- Accession number :
- 22628898
- Full Text :
- https://doi.org/10.1016/j.metabol.2005.08.023