Final answer:
Ingesting carbohydrates before, during, and after heavy resistance training may enhance glycogen replenishment in muscles. Insulin aids in this process by stimulating glucose uptake into muscle cells. However, carbohydrates alone do not maximize muscle protein synthesis, as that requires the presence of amino acids from proteins.
Step-by-step explanation:
Understanding Carbohydrate Ingestion and Resistance Training
When considering ingesting only carbohydrates before, during, and after heavy resistance training, C) It may enhance glycogen replenishment appears to be true. During exercise, the body relies heavily on muscle glycogen as a fuel source. Glucose from carbohydrates is essential for the resynthesis of glycogen stores post-exercise. Insulin, which is released in response to carbohydrate ingestion, facilitates the uptake of glucose by muscle cells and promotes glycogen synthesis. Glycogen serves as a critical energy reserve during subsequent bouts of activity.
It is not primarily that ingesting carbohydrates promotes muscle protein synthesis; it is the presence of insulin which can both promote glycogen storage and aid in muscle protein synthesis by stimulating amino acid uptake and protein synthesis in muscle cells. However, without a source of protein in the diet, which provides the necessary amino acids, muscle protein synthesis is not maximally stimulated.
Thus, while carbohydrate ingestion is not directly related to increased muscle protein synthesis or significant increases in fat oxidation, it is paramount for optimal replenishment of muscle glycogen stores, which can be crucial for recovery and performance during repeated sessions of resistance training.