Time under contraction equals growth is the mantra for gaining lean muscle mass (something you want in order to jack up your metabolic rate), and it's also the formula for
maximum calorie expenditure during the workout itself.
No matter how hard you try to burn additional
calories through crazy training, or express your type - A, workaholic tendencies to get more done across the board, you're ultimately constrained by your own personal daily
maximum caloric
expenditure.