What is lower abdominal strengthening?

Lower abdominal strengthening

1. Lie on your back with your knees bent and your feet flat on the floor.
2. Tighten your belly muscles by pulling your belly button in toward your spine. Keep breathing normally and don't hold your breath.
3. Lift one foot off the floor and bring your knee toward your chest, so that your knee is straight above your hip and your leg is bent like the letter "L."
4. Lift the other knee up to the same position.
5. Lower one leg at a time to the starting position.
6. Keep alternating legs until you have lifted each leg 8 to 12 times.