1) true or false: branched chain amino acids are muscles' preferred source of energy during endurance activity

2)a specific benefit of the amino acid leucine for athletes is
suppression of hunger during physical activity.
increased mental alertness.
maintenance of blood volume.
stimulating gains in muscle mass during strength training.

1. The statement is TRUE.
Protein contributes minimally to the amount of energy that is expended during strenuous exercises. Protein only contribute about 3 -10% of the total energy used. Proteins are degraded to amino acids for oxidation into energy. Branched chained amino acids are especially preferred for oxidation into energy. Examples of branched chain amino acids include: leucine, isoleucine and valine.
2. B
One of the benefits of leucine to athletes is that leucine stimulates protein synthesis in the muscles. Leucine is also closely associated with the release of gluconeogenic precusors. Consumption of leucine before or during physical exercise has been found to be capable of increasing both mental and physical performance.