The obliques are an often neglected group of abdominal muscles located at the sides of your waist. There are two separate pairs of muscles, the internal and external obliques, which work together to rotate the torso. These muscles contribute to side-bending as well. Here are 10 stability ball exercises that focus specifically on the oblique muscles:
1. Roll Up with Twist
Lie on your back with your knees bent and your feet flat on the floor, hip-width apart. Place the Ball on your thighs, gently resting your right hand on the Ball. Place your left hand behind your head. Raise your head and chest up toward the left, keeping that elbow on the floor and your right arm straight. Hold this position for a few seconds, then lower your head back down to the floor. Repeat on the other side.
2. Criss-Cross
Lie on your back with your feet resting on top of the Ball. Your legs should be straight and in a parallel position. Place your hands behind your head and raise your head and upper back off the floor into a stomach crunch. Bend your left knee in toward your chest, keeping your right foot on the Ball, leg straight. From there, bend your right knee toward your chest and straighten your left leg, aiming just above the Ball. As you do this, reach your left elbow toward the opposite knee. Then, as you straighten your right leg, bend your left knee to your chest, reaching your right elbow toward the opposite knee. The Ball rolls back and forth under your right foot. Keep your elbows wide with one elbow remaining on the floor as the other lifts up. Repeat on the other side.
3. Torso Twist
Lie on your back with your knees bent in toward your chest. Hold the Ball in your hands, arms straight up toward the ceiling. From there, simultaneously lower the Ball to your right and your knees to your left. Do not let your knees touch the floor. Then, using your abdominals, bring your knees and the Ball back to the center. Repeat on the other side.
4. Hinge with Twist
Sit on the Ball with your feet flat on the floor, hip-width apart, and your hands behind your head. From there, twist to your left, hinge backward from the hip joint to a slight diagonal, return to vertical, and twist back to the center. Repeat on the other side.
5. Straddle with Side Stretch
Sit straddling the Ball with your knees on the sides and your toes on the floor behind you. With both arms raised overhead, tilt your torso to the right so that you feel a stretch along the left side of your body. The Ball will shift slightly to the left. Repeat on the other side.
6. Stomach Crunch with Twist
Begin sitting on the Ball with your feet flat on the floor, hip-width apart. With your hands behind your head, walk your feet forward until your lower back is resting on the Ball. Raise the upper half of your torso, curling up on a diagonal toward your left knee. As you lower your torso, return to the center. The range of motion is very short, keeping your spine in a C-curve. Repeat on the other side.
7. Skier
Lie with your stomach on the Ball and both hands on the floor. Walk your hands forward until your mid-thighs or knees are resting on the Ball. You should be in a long, straight line from head to toe. From there, tuck your knees toward your left shoulder, rolling the Ball forward on a diagonal. Keep your shoulders still and let your torso twist at the waist. From there, straighten your legs, rolling the Ball back to the starting position. Repeat on the other side.
8. Mermaid
Lie with your left side resting on the Ball and your legs straight and together, so that only your feet are on the floor. Place your left hand on the Ball to help keep it still and reach your right arm overhead. Raise your torso up to a vertical position as you reach your right arm out to the side. From there, lower your torso back onto the Ball, raising your arm overhead. Repeat on the other side.
9. Oblique Crunch
Lie with your left side resting on the Ball and your right leg crossed in front of your left. Keep your left leg straight and your right leg bent with your foot flat on the floor. From there, twist so that both arms are reaching out toward your legs and pulse your torso up in very small movements. Repeat on the other side.
10. Side Sit Up
Sit with your left hip resting on the Ball and your feet supported against the base of a wall. Only the side of your hip should be on the Ball, not your ribcage. Keep your knees and inner thighs together, with your left leg straight and your right leg bent (the top foot will be behind the bottom one). With your hands behind your head, lean out so that you are in a straight, diagonal line from head to feet. From there, bend at your waist to raise your torso up to a vertical position, then lower back to the diagonal. Keep your hips still, so that the hinge happens at the waist. Repeat on the other side.
If you suffer from an injury or other health condition, or have any questions regarding the suitability of stability ball training, please consult your doctor before attempting these exercises.