Final answer:
Muscle glycogen stores can be maximized by a strategy known as carbohydrate loading, which is particularly useful for endurance athletes. Glycogen stored in muscle cells serves as a quick energy source during exercise, with about 70% of the body's total glycogen stored in muscles.
Step-by-step explanation:
Muscle glycogen stores can be maximized by a process known as carbohydrate loading. This is a strategy often used by endurance athletes to increase the amount of glycogen stored in muscles, which serves as a rapid energy reserve during extended periods of physical activity. Glycogen is a polymer of glucose and functions as an energy storage molecule that is made and stored predominantly in the liver and muscles. The liver glycogen maintains blood glucose levels, while muscle glycogen is used during vigorous exercise to sustain contraction via glycolysis.
During the absorptive state, muscle cells convert excess glucose into glycogen for storage via glucose-6-phosphate. Insulin also plays a critical role in this process by promoting the uptake of glucose into muscle and liver cells and stimulating its storage as glycogen. Aerobic exercises such as running a marathon necessitate a significant energy output, at which times athletes may rely on their glycogen stores, enhanced by carbohydrate loading, to keep up with the energy demands.
About 70% of the body's total glycogen is stored in muscle cells, which underscores the importance of maximizing these stores for endurance activities. The conversion of muscle glycogen to liver glycogen and back through Cori's cycle is also an important mechanism in managing energy resources during prolonged exercise.