The philosopher René Descartes gave us the famous notion "I think, therefore I am." He also gave us the far more practical but limiting concept of Cartesian coordinates, which lays a theoretical grid on the universe and describes everything in it as interlocking at right angles. Sometimes this rectangular mode of thinking creeps into the yogasphere, leading to declarations of absolutes about the "best" way to practice. One example of such groupthink is the belief that when you do twists, you must always square your pelvis and preserve that alignment as you turn your trunk. Like Cartesian analysis, this way of looking at twists is useful but often limiting.
The truth is that twists are not one-size-fits-all poses. Like so many other things in yoga, no single prescription will suit every body. To find the optimal pelvic alignment for your body, first experiment with different approaches to see how they feel, and second, learn the mechanics behind twists and figure out what type of alignment is best for you.
Try this: Sit sideways on a sturdy armless chair, with the right side of your body closest to the chair back. Lift your chest, turn to hold the back of the chair with both hands and, exhaling softly, use your arms to twist as far to the right as you comfortably can. Don't deliberately move your pelvis, but if it moves by itself, don't stop it. Remain in the pose, noticing how far you've rotated your trunk and shoulders, and how the posture makes your back and sacrum feel.
Now look at your knees. Most likely your left knee is ahead of your right, indicating that your pelvis naturally turned along with your twist.
Untwist and do the same posture again, but this time, take meticulous care to keep your knees even with each other and your pelvis exactly sideways on the chair seat. How does this version feel?
You might find that it's easier to twist if you let your pelvis turn. Or you might discover that your twist feels deeper and more satisfying if you keep your pelvis square. There's no one right technique for everyone, but a good general rule is that if you don't twist easily, or if you have pain in your sacroiliac region (where the base of your spine meets your pelvis), you are probably better off turning your hips as you twist. If you twist easily and want to go deeper, a squared pelvis might be your ticket.
Hip to be Square?
Twists keep your spinal joints, disks, ligaments, and muscles supple. They also massage your abdominal organs and free your breath by loosening the muscles of your abdomen and rib cage. The core action that makes all this possible is spinal rotation. To visualize how the spine turns, make two fists and then stack them. Imagine that each fist represents a vertebra. Hold the bottom fist still and flex the wrist of the top one. The top fist rotates on the bottom one, in much the same way that one vertebra rotates on another when you twist your spine. When you twist, each vertebra, from the bottom of your spine to the top, turns a little in relation to the one below it, and the sum of all these small movements represents your total spinal rotation.
People often say that keeping the pelvis stable in a twist gives you more rotation in your spine. This is not always true. To understand why, do the same exercise as before with your fists, but this time, when you flex your top wrist, extend your bottom wrist at the same time. Both fists turn in the same direction, so there's little or no rotation of the top one relative to the bottom one.
Similarly, the base of your spine rests on your pelvis, so if you turn your pelvis and spine in the same direction when you twist, your whole spine will turn as a unit, and your vertebrae won't rotate as much on one another—at least at first. But your pelvis can turn only so far, and when it stops, the base of your spine stops too. If you continue turning the rest of your spine, you can eventually achieve just as much vertebral rotation as if you had held your pelvis completely stationary from the beginning.
If both versions of the pose have the potential to rotate your spine equally, how can you determine the one that's right for you? For starters, consider how easy or challenging it is for you to twist.
If your spine does not twist easily and you choose to keep your pelvis stable in Marichyasana III (Marichi's Twist III), shown in the photo above, you'll have a tough time getting your shoulder far enough across your body to get your arm in the optimal position. (Your trunk muscles alone cannot rotate your spine to its maximum potential. To twist fully, you need to bring your shoulders around far enough that you can press your arms against a solid object and find some leverage. For example, in Marichyasana III, you press your arm against the outside of your bent leg to help you turn.) But if you choose to turn your pelvis with the twist, your whole trunk will follow and your shoulder will come farther across, giving you a fighting chance of placing the arm on the outer leg.
The bottom line is that the way you move (or stabilize) your pelvis will affect the position of your shoulders at the end point of your twist—which will, in turn, affect your ability to lever yourself around. This is the main reason that yoga students who are less flexible often benefit from turning their pelvis along with their twists. On the other hand, if you twist easily in Marichyasana III, turning your pelvis may bring your shoulder so far past your bent leg that you put your arm at a mechanical disadvantage, reducing its leverage. This is the main reason flexible students often get more spinal rotation when they keep their pelvis square.
On the Sidelines
Another element to consider when you do your twists is the health and stability of your sacroiliac (SI) joints. The sacrum, which is the large triangular bone at the base of your spine, is wedged between the two ilium bones, which are the left and right "wings" of your upper pelvis. The contact surfaces between the sacrum and the ilium bones are known as the SI joints (there's one on each side).
Yogis frequently suffer from a painful sacroiliac injury when one side of the upper sacrum shifts too far forward, pulling it away from the ilium and out of the joint on that side, which can occur in twists and forward bends. Twists can worsen this injury because they naturally rotate one side of your sacrum forward: When you twist to the right, you risk dislodging your sacrum from your ilium on the left, and vice versa. (You often won't know that an SI joint has separated until after you practice and you feel a dull ache on the back of one side of your pelvis.)
If you rigidly keep your pelvis pointing straight ahead and twist forcefully, you exaggerate this risk. One way to avoid this problem is to consciously relax the muscles that surround your spine, waist, and rib cage while you twist, so your vertebrae turn more freely relative to one another and don't transmit as much force to your sacrum. Another way is to let your pelvis turn while you twist.
Turning your pelvis along with your twists is usually safer for your SI joints than holding it square, for three reasons. First, when you begin a twist by rotating your pelvis, your torso turns farther. Because of this, your pose feels complete sooner, and you are less likely to push yourself beyond your capacity. Second, in poses like Marichyasana III, turning your pelvis makes it easier to reach your arm across your bent leg, so you are less likely to slump your spine toward that leg in an effort to improve your arm position. Slumping is detrimental because it pulls the top of your sacrum forward.
Third, turning your pelvis along with a twist can help protect your SI joint because it allows your ilium to move forward in unison with your sacrum so that the two bones stay together, rather than separating. To maximize this SI-protecting effect, you should also "dog tilt" one side of your pelvis as you twist; that is, when you twist to the right, tilt the top of the left ilium (pelvic rim) forward from the sitting bone. This will help the upper ilium follow the sacrum forward.
Try this exercise to help determine which twist works best for you. Sit either on the floor or on a stack of folded blankets, and straighten both legs in Dandasana (Staff Pose). Bend your right knee, placing your right heel near your right sitting bone. Reposition your pelvis so that it forms a precise right angle with your straight leg. Press your right hand down on the floor behind you and hold the front of your right knee with your left palm as you tilt the top rim of your pelvis forward.
Exhaling, pull with your left arm to turn your trunk to the right, keeping the right knee stable and taking care not to turn your pelvis at all. Instead, relax your front and side belly muscles to soften the waist, and allow them to stretch freely as you turn first from your lower back and lower rib cage, then from your upper ribs and shoulders.
As you do this, be careful not to pull the left side of your sacrum forward. With each inhalation, lift your spine tall; with each exhalation, turn farther into the pose, always keeping your pelvis square. Cross your left arm to the outside of your right knee only if you turn so far that you need more leverage to turn effectively.
Now, without coming out of the pose, see what happens if you turn your pelvis bit by bit along with your twist. On your next exhalation, slide your right sitting bone backward a half inch along the floor without lifting it up, and twist deeper into the pose. As you turn your pelvis, press your left sitting bone down and put more weight on its front edge to tilt your left pelvic rim as far forward as you can. Stop your pelvis there, and on your next exhalation, turn your spine farther.
Repeat this sequence several times. Observe carefully at each stage to feel what degree of pelvic rotation, if any, puts the arms in the best position and helps you twist most deeply, while also keeping your spine tall and avoiding strain on your back and sacrum.
Once you've found your optimal degree of pelvic rotation in Marichyasana III, you can use a similar technique to find it in other twists. As you do, keep in mind that for the pelvis in twists, the right angle is not always a right angle.
Roger Cole, PhD, is a certified Iyengar Yoga teacher and sleep research scientist in Del Mar, California. For more information, visit http://www.rogercoleyoga.com.