A good supplement to all those crunches you may be doing is some back work. You want to keep it balanced and one of my favorite lower-back exercise is the Superman. All you need to do this exercise is your body weight, no equipment necessary. Here's how:

• Lie face down on your stomach with arms and legs extended. Keep your neck in a neutral position.
• Keeping your arms and legs straight (but not locked) and torso stationary, simultaneously lift your arms and legs up toward the ceiling to form an elongated "u" shape with your body — back arches and arms and legs several inches off the floor.
• Hold for two to five seconds and lower back down to complete one.
• Do three sets of 12.

Fit's Tip: Exhale as you lift your arms and legs and inhale as you lower them back down. When you have completed all three sets, or even in between each set, take a Child's Pose [1] to stretch your back.