First, resting metabolic rate is increased when one gains muscle mass. While the energy expenditure per pound of lean body mass does not change, the addition of more muscle mass means a larger energy expenditure or higher metabolism at rest. Second, the more muscle mass one has the greater the post exercise oxygen consumption. When strength trained individuals were compared to nontrained individuals, there was no difference in post exercise oxygen consumption per pound of muscle. However, since the strength training individuals have more muscle mass, they burn more calories during the post exercise period.
Strength training increases energy expenditure during a training session.
The high intensity or anaerobic nature of strength training indicates a high utilization of carbohydrates during a training session. The increased energy demands are obtained by burning more calories, and a good portion of the calories are coming from fat stores. So it is comforting to know while one is exerting themselves through a high intensity workout, that the hard work will result in a faster metabolism that continues to burn calories even after the workout. Dictionary of the Sport and Exercise Sciences. Human Kinetics Publishers.