You won't feel thirsty until you are already a little dehydrated and have lost important fluids and electrolytes. The goal is to keep performance up by maintaining hydration. Let the kids see you guzzle water or some type of sports drink. Carry a water bottle with you at all times. It was originally thought that unless you were doing strenuous exercise for 60 minutes or more, water was the best thing for you.
Sports drinks are popular for different reasons.
One is that they are more palatable than water to some athletes, therefore the athlete ends up drinking more fluids and maintaining hydration easier. Another reason is if you have 4-5 hour workouts, it is very important that your athletes are refueling during practice. This can easily be done with a quick snack or a sports drink. Hydration prior to workout is still a big consideration. It is possible that if your athlete is dehydrated when they come to the gym, a sports drink might not give them what they need as much as water would.