A dumbbell may be included in most bodyweight-only abdominal exercises. Other free weights, such as medicine balls and exercise plates, may be easier to use for some exercises, but the dumbbell will work to add extra resistance for almost any abdominal exercise. When designing an ab workout, do exercises that will, when combined, hit all parts of the abs from the deep transverse abdominis muscle to the oblique muscles on the side of the waist, instead of just focusing on the rectus abdominis or "six-pack" muscle. Start with five reps of each exercise and use heavier weights or add reps as you get stronger.
Standing Twist With Dumbbell
The standing twist with dumbbell exercise is unique because it is one of the few exercises that is done standing up. The exercise works the oblique muscles primarily, but also the transverse abdominis as a stabilizer. The exercise is done by holding a dumbbell in front of your stomach with your elbows bent. Use a neutral ("hammer") grip on the dumbbell, which means that the dumbbell is aligned vertically, rather than horizontally. You will twist slowly to the right and then twist slowly to the left. You will return to center to complete one rep. The dumbbell should stay directly in the center of the stomach at all times.
Dumbbell Push Crunch
The dumbbell push crunch is performed lying faceup on a decline bench, though it can also be done lying on the floor. The head should be at the bottom of the decline bench with the feet hooked under the foot pad. A single dumbbell is held straight in the air above the chest. You will squeeze your abs and raise your head and shoulders off the bench. You should reach toward the ceiling with the dumbbell. One rep is completed by lowering yourself slowly back to the bench. The lower back should stay flat against the bench at all times. The rectus abdominis is the main muscle used in this exercise.
V-Sit Crunch With Dumbbell
The V-sit crunch with dumbbell is an advanced exercise that will utilize all of the muscles of the abs for movement and stabilization. The exercise may be attempted without the dumbbell first to find your balance point before adding the challenge of including the extra weight. The V-sit crunch is done by first sitting on the floor and leaning back a little. A dumbbell may be held in front of the stomach horizontally between your hands with the arms bent at right angles. You will bend your knees and lift them off the floor toward your chest. You will now be balancing only on your buttocks. From this starting position, you will lie back and extend your legs straight. The arms will be extended straight, too, so the dumbbell is over the thighs. You will bring your legs and upper body back up to the starting position and twist your shoulders to the right. You will twist your shoulders back to center, extend your legs, lean back and straighten your arms again. The next time you crunch up, you will twist to the left. The dumbbell should be brought back toward your stomach with the elbows bent every time you crunch up. You will alternate sides and count each crunch as one rep.