Carbohydrates serve as a primary energy source during high-intensity training, fueling the muscles and brain for optimal performance. They are stored in muscles and the liver as glycogen, which is rapidly converted to glucose during intense workouts. Adequate carbohydrate intake before and after training replenishes glycogen stores, enhancing recovery and sustaining energy levels. Proper management of carbohydrate consumption is essential for athletes aiming to maximize performance and maintain endurance.