Muscle glycogen serves as a critical energy source during exercise, particularly in high-intensity situations. Glycogen is stored in muscles and the liver and is broken down into glucose to fuel muscle contractions. During prolonged exercise, such as endurance activities, glycogen levels become depleted, which can lead to fatigue and reduced performance. Maintaining adequate glycogen stores through proper nutrition and hydration is essential for sustaining energy levels and maximizing workout effectiveness. Post-exercise replenishment of glycogen through carbohydrate-rich foods is vital for recovery and performance continuity.