The Firm: 500 Calorie Workout

With seemingly every workout video on the market touting vague or impossible results, this one relies on concrete math for its promises: it burns 500 calories, guaranteed. Created with precise intervals and intense movements, the 60-minute routine is guaranteed to eliminate its target number if executed properly, and fitness expert Kelsie Daniels makes sure each element of the workout is thoroughly demonstrated and explained, so no viewer is left too confused to hit the mark.

• health and fitness