The benefit: This exercise works your entire abdominal muscle complex while keeping your lower back in its naturally arched position. So it minimizes stress on your spine while increasing the endurance of the muscles, which helps prevent lower-back pain.
Lie on your back on the floor with your right leg straight and flat on the floor. Your left knee should be bent and your left foot flat. Place your hands palms down on the floor underneath the natural arch in your lower back [A]. Slowly raise your head and shoulders off the floor without bending your lower back or spine, and hold this position for 7 to 8 seconds, breathing deeply the entire time [B]. That’s 1 rep. Do 4 to 5 reps, then switch legs and repeat. To make it even harder, raise your elbows off the floor as you curl up.