Does drinking a sports drink mid-race help you run faster? Isotonic drinks like Gatorade contain sugars and electrolytes designed to replace what the body loses through sweat. But do they actually improve performance during a run? You recruit 30 long-distance runners and time them on a 5 km cross-country course. Then you split them into two matched groups with similar average times. Two weeks later both groups run the same course again. At the midway watering station one group receives Gatorade. The other group receives plain water. You compare each group's average finishing time from the first and second race. The difference shows whether the isotonic drink gave runners a measurable edge.