Runners who increase their carbohydrate intake and reduce exercise before a competition are doing what?

The correct choice reflects a strategy commonly used by athletes known as carbohydrate loading. This practice involves increasing carbohydrate intake in the days leading up to an endurance event while simultaneously tapering (reducing) exercise. The primary goal of carbohydrate loading is to maximize glycogen stores in the muscles. Glycogen serves as a vital source of energy during prolonged physical activities, allowing athletes to perform at their best for longer durations.

By consuming carbohydrates before the competition, runners allow their muscles to store more glycogen, which can be crucial for when they need high energy output, particularly in events that last longer than 90 minutes. This method has been particularly popular among distance runners and endurance athletes because it helps delay fatigue and improves performance.

Other options are not as fitting for this scenario. Hydrating focuses on fluid intake and ensuring proper hydration, which, while essential for performance, does not specifically relate to the manipulation of carbohydrate levels. Resting involves ceasing physical activity altogether, not necessarily aligning with the dietary adjustments being made. Carbo-energizing is less commonly used and less specific than carbohydrate loading; it does not encompass the recognized strategy of altering carbohydrate intake and reduces exercise properly.