Clamshell exercises can help you work on balancing the muscular effort between your pelvic floor and your inner and outer thighs. Creating balance among these muscles, including the piriformis, helps to avoid overuse issues like sciatica, according to Lynne Robinson, author of “The Official Body Control Pilates Manual.” Try this Pilates clamshell sequence after checking with your doctor to ensure that these exercises are appropriate for you.
Lie on your back with your knees bent and your feet flat on your mat. Place a plump pillow between your knees and lengthen your spine. Exhale as you engage your inner thighs and squeeze the pillow. Inhale as you release the pressure without dropping the pillow. Do not allow your tailbone to lift up as you squeeze; keep your spine long so that your tailbone stays down, recommends Robinson. Perform 10 squeezes, noticing how it feels to keep your pelvis steady while engaging your inner thighs. Put the pillow aside where you can reach it.
Lie on your side with your spine aligned with the edge of your mat. Stack your legs one on top of the other, and tuck your knees forward about 45 degrees. Exhale as you lift the top knee up, keeping your feet stacked. Your legs should look like an open clamshell. Inhale as you close your legs. Repeat this movement 10 to 15 times, keeping your pelvis steady throughout the movement. Intensify this exercise by squeezing your buttocks three times in the open clamshell position. Perform all of the side clam exercises before switching to your second hip and leg.
Stay in the same position that you used for open clam and place the pillow between your knees. Keep your feet stacked as you slowly exhale and gently squeeze the pillow. Keep your spine long so that your back does not tuck or arch. Inhale as you release the pillow. Repeat this movement 10 to 15 times. To intensify this exercise, perform three tiny pulses when you are in the squeezed position.
After performing clam squeeze, put the pillow aside. Keep your knees pressed gently together and rotate your top thigh inward to lift your shin and foot upward. Your clamshell is now opening to the rear. Exhale as you lift up; inhale as you close the clamshell. Repeat this movement 10 to 15 times without allowing your spine to tuck or arch. To intensify this exercise, add tiny pulses – about ½ inch -- in the open clam position.