The second day, let’s start really getting into it. Start by lying flat on your back with an exercise ball under your heels. Bridge your hips up, and hold that position through the entire exercise. Flex your feet and dig your heels into the ball. Place your arms straight out to your side for support. Slowly roll the ball toward your body as you curl your heels. Keep your hips in the bridge position; don’t thrust them toward the ceiling as you do the move. Then slowly return to the start position to complete one rep. Do three sets of 20.