Because of time constraints and convenience, cardiovascular and strength training programs are often combined, even though it's not been clear how one exercise affects the performance on the other. An article in the May 2005 issue of Journal of Strength and Conditioning Research looks at the effects of aerobic and resistance training and the combination of the two on excess postexercise oxygen consumption, a measure of energy expenditure.

The journal article described a study in which 10 men underwent four trials: One for resistance, another for running, a third for resistance and then running, and one for running and then resistance. Researchers found that resistance training produced greater postexercise oxygen consumption than aerobic exercise.

In the combined sessions, postexercise oxygen consumption was greater when the men ran before doing resistance training. The study concluded that if people want to burn more calories, they should do resistance training. In a combined session, they should start with aerobic exercise followed by resistance training.