The basic movements of this exercise develop the strength of the abdominal muscles, while the use of the ball helps increase stability.

1 Slowly roll down onto the ball, letting your spine follow its curve, and place your head and neck in a comfortable position on its back. Place your hands at the sides of your head and position your feet hip-distance apart.

2 Draw your abdominal muscles, then exhale and curl your entire spine up, starting from the neck. Flex at your torso until the distance between the top of your pelvis and the bottom of your ribs stops shortening.