If you look at an anatomical picture of the human skeleton, it's easy to assume that being fully symmetrical is the norm. But it's extremely rare for us to stand equally weighted on both feet, unless instructed to do so in an exercise class.
Habitually standing toward one hip, sitting cross-legged in the same way or favoring one side of your body when you exercise can create asymmetry in the body when done day after day, year after year—in particular, it can cause pelvic asymmetry.
Often, people are completely unaware they have pelvic asymmetry—it may cause no pain or problems with movement. In fact, in one study of healthy 18 to 39-year-olds with no pelvic or lower back pain, more than two-thirds of them had pelvic asymmetry.1 But over time, it can have repercussions for the lower back, hips, knees and shoulders (see box, below).
Types of pelvic asymmetry
Pelvic asymmetry can actually occur very quickly in the body, given the right circumstances. In one study, when over 300 people with symmetrical alignment of the pelvis repeatedly performed one-sided exercises, a quarter of them developed pelvic asymmetry.2
These results led the researchers to conclude that there are two types of pelvic asymmetry: 'fresh' asymmetry, which is typical for activities of daily living, and 'cemented' asymmetry, which is resistant to correction and often accompanied by symptoms.
'Fresh' asymmetry can come and go as you shift your habits and respond to feelings of tightness and the need to instinctively balance out.
This can occur from activities of daily living or movement habits in which you lean into ligaments in a cross-symmetrical way—for example, from sitting cross-legged the same way, standing toward one hip, carrying a heavy bag on one shoulder, favoring one leg when cycling or doing other forms of exercise, or driving.
Gaining awareness of these habits—such as how you wear your bag or sit at your desk—and avoiding or changing them can have far-reaching effects.
If pelvic asymmetry is a result of exercise, it's worth having your posture and equipment evaluated to prevent long-term problems. For example, are your bicycle handles in line with the seat?
As Thomas Hanna, director of the Novato Institute for Somatic Research and Training in Novato, California, put it: "If you can sense it and feel it, you can change it".
When asymmetry ceases to be 'fresh,' there is a tightening of the fascia (connective tissue) into new shapes and ways of being that are more resistant to correction.
This is often accompanied by symptoms, most associated with the LPHC area—the lumbo-pelvic-hip complex, where 'lumbo' refers to the lumbar spine or lower back. This is attributed to issues in the piriformis and iliopsoas muscles in the buttock and hip.
Correcting pelvic asymmetry
The good news is that pelvic asymmetry can be very responsive to movement that helps correct the imbalance. In a study of people with either C-type or S-type scoliosis (differing shapes of the spine) along with a difference in leg length, all were able to regain symmetry via manual, fascial and osteopathic manipulation procedures, and 78 percent reported an improvement in functional ability and pain.3
But even simple exercises you can do at home can help to unravel asymmetry in the body. Try the seated and standing movements on the following pages to bring your body back into alignment.
How does pelvic asymmetry happen?
In the lower back, most spine extension (lengthening) takes place between the lowest lumbar vertebra (L5) and the top sacral bone (S1), and this is also where the brunt of any shifts are felt (see upper illustration). A shift of the pelvis in any direction can pinch nerves and encourage disc herniation in this area.
Further down, the sacrum fits into the pelvis at the sacroiliac (SI) joint, the site of much lower back pain. If the pelvis is tilted, it can be too lax on one side and too tight on the other.
In cases of cemented pelvic asymmetry (see main text), this may relate back to early life, as the sacrum's five separate vertebrae (S1-S5) begin fusing into one bone at around 16 to 18 years of age and are usually completely fused by age 30.
The SI joint has almost no direct muscle support except from the piriformis, which can be a lower back troublemaker, as it is the only muscle that attaches directly to the sacrum.
It is small and goes deep into the buttock, starting at the lower spine and connecting to the upper surface of each thighbone. If it is tight on one side, that leg may rotate out more; SI issues are seen in the hip with least flexibility, where it will become compressed.
The psoas muscle is a major stabilizer for the lower back and joins the spine to the legs. If it becomes tight and disengaged through chronic stress, trauma and poor postural habits, secondary stabilizers such as the transverse abdominus (TA) and multifidus muscles take over. They can become tired and weakened through continual and inappropriate usage.
The TA is a deep
muscle layer of the front and side abdominal wall—a key component of the 'core.' It is much like an inner corset, and with pelvic asymmetry, it becomes bunched up on one side and elongated on the other.
The multifidus is the only muscle that increases in strength when it elongates, which you can feel when you lift up through the spine, an action necessary for helping to correct pelvic asymmetry. It also coactivates with the SI joint in a loop for lower back stability.
The TA and multifidus work in tandem for this support, and lower back pain is common when it is interrupted.1
Exercises to unravel pelvic asymmetry
Beginning on the ground, try the following asymmetrical exercises to become aware of any asymmetry in your body. You may need more strength on one side and ease in the other. Alternating these with symmetrical positions, you can help imbalances come into alignment around the midline.
1) Clamshell. This exercise strengthens the buttock muscle to support pelvic symmetry. Lying on your side with knees bent up together, lift the top knee, keeping the feet connected. Do 10 to 20 repetitions on each side, holding the knee up for about 5 seconds. Don't twist the spine to get more movement, go with the range of motion offered by your hips, which you may notice improves as you do this regularly.
2) Free crawling. Crawling creates motion across the 'diagonals' of the torso, where pelvic asymmetry is seen. This is where you 'move out from the center,' so you can feel how you move from your middle outward. When you crawl on all fours, you can feel where any tightness in the tissues is affecting movement. You are free to move in any direction here, so you can adapt to restriction without further injury.
3) Sunbird. Reaching out from the center, moving side-to-side through the opposite arm and leg creates a healthy sideways motion in the pelvis from the naturally extending act of reaching. From all fours, exhale down toward child pose, then inhale up through the belly to lift the opposite arm and leg out from the center, drawing in the lower ribs. Exhale down into the symmetry of child pose, then repeat on the other side, alternating on each inhalation before settling down for a minute or so.
4) Pigeon pose. This piriformis stretch can help ease buttock tightness. From all fours, bring one knee to the back of the same wrist and, without any force, move that foot over to where it comfortably comes beneath your groin—this is your natural range of motion, so do not strain here. Hold and breathe deeply, with either your torso held up or releasing down. Feel the difference on each side.
5) Sitting from open hips. Sit in a wide-legged seated position and feel which natural angle allows the pelvis to feel balanced. You can place blankets under your knees if it helps. Lift through the front spine to create space in the pelvis.
Coming to standing, the movement of the pelvis on top of the thigh bones is freed up, which encourages your body to find its natural symmetry, especially where habits have created a new 'normal.' You can move in the following ways to work within your comfortable range of motion and coax out changes in tissues, rather than force an imposed will of 'fixing' something wrong.
1) Rotate the hips, one direction, then the other, and switch to notice the difference and feel areas that may move more easily and those that feel more restricted on each side. Then move the hips in a figure-eight motion, one direction and then the opposite, which may feel less natural and so will help form new neural wiring and reconfigure dominance on one side of the body and brain.
2) Lift one knee at a time as you inhale and lift the hands at the same time, as if lifting the knee with invisible strings from your fingers, just as high as feels steady and comfortable. Do this side to side in a stepping motion. Keep a steady focus to notice imbalance, but simply let it unravel, rather than trying to 'fix' it. You can step forward and then backward.
3) On an inhalation, lift both arms above your head as you also lift your heels, stabilizing with the base of your big toes pressing into the ground. Exhale back down again.
4) On an inhalation, lift one arm over the head and bend sideways to lengthen the whole of one side. Exhale down back to center, and before lifting to the other side, 'bridge' by lifting the arms and heels as in the last exercise. Move side to side, lifting in the middle between each side flank stretch.
5) Forward bend against a wall to press back equally from both hands (positioned the same distance from the floor) and draw back the tops of the thighs equally to lengthen both sides of the body.