To see the results of strength training, you must overload the muscles, putting enough effort to make the adaptation happen. Some trainers recommend doing three to five sets for maximum muscle gain, while others say that one set per exercise is as good as two or more. The correct answer depends on you, your goals and your current level of physical fitness. If you really want to increase strength, endurance and muscle growth, several approaches have an advantage. But training with one approach can suit many.