Training With Amino Acids
How these building blocks of protein can lead
to an increase in strength and power

Amino acids are considered to be the building blocks of protein. Amino acids are used as supplements because some are believed to help increase muscle tissue synthesis, which can ultimately lead to an increase in strength and power.

During high-intensity exercise, the body increases the levels of glucocorticoids. Glucocorticoids include cortisol and androgens that increase the rate of muscle protein breakdown. The intake of amino acids has been shown to inhibit muscle protein breakdown while stimulating protein buildup. If athletes break down lean tissue during resistance training and if higher concentrations of amino acids promote tissue synthesis, then athletes may benefit from increasing the amounts of amino acids in their diet.(1)

Amino acids may increase tissue synthesis through increasing plasma amino acid levels, which in turn may stimulate the release of growth hormone releasing factor. The release of growth hormone releasing factor may be due to an insulin-mediated response, which would then release growth hormone.

Functions of Glutamine
Glutamine is the most versatile of the amino acids. It is not an essential amino acid, because it is synthesized in the body by glutamine synthetase from other amino acids, glutamic acid, valine and isoleucine. However, in certain situations more glutamine may be needed than can be synthesized. In this case the amino acid could be termed "conditionally essential."

Glutamine makes up 60 percent of the total amino acid pool in the muscle. Under certain situations where the body is stressed, such as surgery, trauma and infection, muscle glutamine reserves are depleted. The body cannot make enough in this situation, and this produces a catabolic state. Catabolism involves the breakdown of large molecules, such as muscle protein, into smaller molecules to release energy. During the prolonged stress of exercise or when the body is producing high amounts of lactic acid, as in weight training, glutamine stores in the muscle may be utilized heavily. Depleted muscle glutamine stores will inhibit protein synthesis, which also may cause a catabolic state in the body. Exercise causes an increase in glucocorticoid release. Glucocorticoids will cause an increase in glutamine release from the muscle and an increase in glutaminase activity. This will allow glutamine to be released from the muscle even when glutamine levels are low.Another important role of glutamine is that it maintains cell volume in the muscle. When glutamine is taken up by the muscle, electrolytes are also taken up, causing an osmotic swelling in the skeletal muscle. If cell volume is not maintained, due to decreased glutamine, then the muscle weakens and contributes to overall muscle catabolism.

BCAA Functions
The branch-chain amino acids valine, leucine and isoleucine are essential in the diet, and make up one third of muscle protein. One of the main functions of BCAAs is to be used as a fuel during exercise in order to spare other amino acids.1 Another function of BCAAs is helping in protein synthesis or anticatabolic. Both valine and isoleucine are used as substrates for glutamine, which is very important to protein synthesis. The third BCAA leucine, is also believed to have anabolic or anticatabolic effects due to beta-hydroxy beta-methybutyrate or HMB. HMB is believed to help increase the ability to build muscle and burn fat in relation to intense exercise.

Amino Acids & Altitude Training
When giving training considerations for athletes or individuals who will be exposed to altitude for any period of time, the major concern is lack of aerobic capacity, which is impaired due to hypoxia. While simple exposure to altitude, over time, will self-correct aerobic capacity, athletes who train regularly at great elevations or people who do a great deal of snow skiing, may be placing their strength and power at risk.(2)Several recent research studies have shown that chronic exposure to training or recreation at altitude can lead to muscle atrophy due to protein catabolism, loss of body weight, decreased energy reserves in the muscle and weakened immune status.(2,3,4) These studies all showed that subjects who chronically trained at altitude and who daily consumed extra protein, rich in branch-chained amino acids, were at less risk than those who consumed a normal diet. Therefore, as this problem does not self-correct, it would appear that individuals chronically exposed to altitude should alter their food consumption through diet or regular amino acid supplementation in BCAA and glutamine.

- by David Pearson, PhD, CSCS, Exercise Physiologist

References
1 Plaatell C. Kong SE, McCauley R, Hall JC. "Branch-chain amino acids." J Gastroenterol Hepatol. 2000, 15(7):706-717.
2 Schena F, Guerrine G, Tregnaghi P, Kayser B. "Branch-chain amino supplementation during trekking at high altitude. The effects on loss of body mass, body composition, and muscular power." Eur J Appl. Physiol. Occup. Physiol. 1992, 65(5) :394-398.
3 Bigard AX, Lavier P, Ullmann L, Legrand H, Douce P, Guezennec CY. "Branch-chain amino acid supplementation during repeated prolonged skiing exercises at altitude" Int J Sport Nutr. 1996, 6(3):295-306.
4 Bigard AX, Satabin P, Lavier P, Canaon F, Tailandier D, Guezennec CU. "Effects of protein supplementation during prolonged exercise at moderate altitude on performance and plasma amino acid pattern" Eur J Appl. Physiol. Occup. Physiol. 1993,66(1):5-10.