Final answer:
Exogenous amino acids are essential after high-intensity activities and strength training to meet muscle metabolic needs, repair muscle damage, and build new muscle tissue, as essential amino acids cannot be produced by the body and must be consumed through diet or supplements.
Step-by-step explanation:
Exogenous amino acids are required following high-intensity activities and strength training because they serve multiple critical functions: meeting the basic metabolic needs of muscle tissue, repairing muscle damage caused by high-intensity exercise, and building new muscle tissue. Therefore, the correct answer is D) All of these are correct.
When you engage in high-intensity or strength training, your muscles are subject to stress, leading to microtears and the breakdown of muscle fibers. This process requires sufficient amounts of amino acids, particularly essential amino acids like the branched-chain amino acids (BCAAs) -- leucine, isoleucine, and valine -- which are vital for muscle protein synthesis and recovery. Since they cannot be synthesized by the body, these amino acids must be ingested through the diet. Additionally, glutamine, although not an essential amino acid, becomes conditionally essential during periods of intense physical stress and can support immune function and gastrointestinal health, which could be beneficial for athletes engaging in rigorous training.
While there is some debate on the efficacy of amino acid supplementation, a balanced intake of these nutrients, whether through diet or supplements, is crucial for the recovery and growth of muscles post-workout, as well as for preventing protein-energy malnutrition in athletes.