4 Core Exercises for the Abs and Waist
The U crunch is a core exercise that strengthens the abdominals and stretches the lower back.
Start by lying on your back with your feet up, your knees bent, and your arms up toward the ceiling. Flex your abdominal muscles to curl your spine forward so that your chest and ribs pull down toward your navel and your pelvis rolls back toward your ribs.
Aim for half the movement to come from your upper body and half from the pelvis roll. Hold the contracted position for one second and then unroll back to the starting position.
Be careful not to overarch your lower back in the starting position.