I'm talking about requirements for the average person building muscle. It sounds like you're talking about workout intensity for a specific goal or sport. High intensity sports and higher rep weight lifting favor the fast glycolytic energy system. Low rep powerlifting and strength training favor the ATP-PC energy system, and endurance sports favor the oxidative system.

If you're playing a high intensity team sport or lifting in the higher rep ranges then supplying carbs for the glycolytic system is good for overall performance.