By Jessica Smith for Shape.com
Amp up your abs routine by adding a little extra weight! You'll force your muscles to work even harder to help stabilize your trunk while performing moves that closely mimic everyday activities (climbing a ladder, holding onto objects while sitting up in bed, or reaching for the top shelf in your closet). Plus, the extra effort required to move that additional weight means you'll burn more calories and flatten your stomach faster. So grab a set of dumbbells and give this workout a go!
How It Works: Do 1 set of the prescribed number of reps for each exercise, moving from one to the next with little to no rest in between. Do the full circuit 1 to 3 times, depending on how much time you have. It's great after a cardio session, during a strength workout, or on its own for a killer core workout.
You'll Need: A set of dumbbells heavy enough to challenge you by the final rep of each set (5 to 10 pounds, depending on level); you may want a mat or towel for the floor work.