Myth: Cardio burns more calories than strength training.
Contrary to long-held belief, strength training is—as new studies have shown—superior to steady-state cardio in caloric burn. In one University of Southern Maine study, participants blasted as many calories doing 30 minutes of weight training as they did running at a six-minute-per-mile pace for the same amount of time.
The other huge benefit of weight training? It boosts your metabolism after your workout—and builds muscle that will further increase your fat-burning potential in the long run. "If you do steady-state cardio, when you leave the gym, that's it for your calorie burn," says David Jack, general manager of Competitive Athlete Training Zone in Acton, Massachusetts. "But when you do strength work, you'll continue to burn calories for up to 36 hours."
I have been seeing this become such a truth in my calorie burns every week. When I add more weight training or just a core workout in circuit training I see a lot more results then when I just do cardio. If you already have the muscle mass then just use light weight with 3 sets of 12 - 15 and usually do this for about 30 minutes focusing on core, upper, or lower body muscles.