The crunch is a classic because it works. Lie on your back, knees bent and feet flat on the floor. Put your hands behind your head, elbows facing out. With your low back on the floor, use your ab muscles to lift your upper body as far as you can. Hold the pose, and then slowly return to the floor. Do three sets of 10-12 reps. Rest for 30 seconds in between all ab exercises.
The reverse crunch targets the lower abs, which are tough to tone. Keep your arms at your sides, palms down. Use the abs to lift the legs, bringing the knees directly over the hips. Contract the abs further and raise your hips and lower back off the mat, knees toward your face. Hold briefly before lowering back to the mat. Don’t let your feet touch the floor. Do three sets of 10-12 reps.
Grab a dumbbell, medicine ball, or cable weight system. Choose enough weight to work the muscle to fatigue within 12 reps. Kneel on one knee with the other foot forward. Use both hands to lift the weight up over your shoulder, on the foot-forward side. Don’t turn your torso. Slowly lower the weight to opposite hip. Head hips, and torso should face forward at all times. Do eight to 12 reps before switching sides.
Choose a medicine ball or dumbbell. In a sitting position, lean back slightly and engage the abs, with your knees bent and heels touching the floor. Hold the weight close to your body and slowly twist your torso to one side. Pause briefly before rotating to the opposite side. Contract the abs deeply as you twist. Work up to three sets of 12 reps.