I injured my lower back more than 40 years ago doing forward bending and twisting stretches. I certainly didn’t need to add mobility to my spine, but the stretches felt good and relieved some of the negative effects of the positioning I was doing in my dance training. I herniated a lumbar disk and overstretched both spinal and sacroiliac ligaments. For years I would get sciatica from sitting on sofas, car seats, airplane seats – any soft seat that would encourage reversal of a normal lumbar curve. Alexander Technique training made it possible for me to stand and sit in a healthy, upright manner, such that I no longer had sciatic nerve impingement. But I know very well how to bring the pain back. Reversing my lumbar curve in sleep and semi-supine work are two quick ways to make my back hurt.

First, it’s important to consider how the sacrum is suspended within the pelvis. In the following illustration, one can see this clearly. When a healthy lumbar curve is present and the spinal extensors are normally active, the sacrum inclines well forward and is suspended from the pelvis by the sacroiliac ligaments.

Human skeleton: pelvis and sacrum. Isolated on white. Medically accurate 3D illustration

However, when the spinal musculature is less active, in lying down, or in sitting while inclined back, the lumbar curve can easily be flattened or even reversed, allowing the distortion of vertebral disks and putting pressure on nerves, as in my case.

What I did not realize with all of the stretching of my lower back is how important good tension is in spinal muscles both to support the movement of the limbs and to protect the spinal cord from damage. There is simply no good reason to make the spine overly flexible in flexion or in rotation.

Today I’m pain-free while standing, running, skiing, swimming, or chopping wood. I’m even up to the task of sitting during a trans-Atlantic flight, but I must consciously work on myself to prevent collapse in bad seats and even in semi-supine and in bed.

When standing well, spinal extensors are stimulated by gravity to lengthen the spine so that it can support the movement of the limbs without distortion. Imagine if the large muscles of the arms and legs were to contract without active spinal muscles – the body would simply deform, and no action, not walking or lifting, could be accomplished.

Semi-supine, or constructive rest, is used in the Alexander Technique as a means of working on posture relieved of some of the strong habits associated with standing.

Anthropologist Raymond Dart coined the term “semi-supine”. Thus, while the trunk is lying down in this condition, the legs are standing. If the weight of the legs is directed to the feet in semi-supine, I believe that the reflexes that tend to lengthen the body when fully standing are lightly stimulated (interosseous reflex of the positive supportive response), so the spinal extensors will be lightly active. Also, when the feet are on the ground in semi-supine, muscles must be active to keep the knees from falling inwards or outwards. This enables one to work on the dynamic use of leg muscles that one should have in standing – the muscles that work in standing can be dynamic and constantly altering length (myotatic reflexes).

This assumes conscious direction, for, if one simply lies down and folds the legs, the large muscles of the legs will move the unsupported spine and pelvis, such that the lumbar curve will reverse and the lower back will flatten. The same is true with sleep.  If one lies flat on the back with legs straight, the lumbar curve will persist in sleep. However, if one rolls on one’s side and draws the legs up, the lumbar curve will flatten. For someone like me, with damaged lumbar disks, the result can be pressure on nerves and a worsening of disk deformity.

So consciousness is important, certainly in conscious rest, and even in sleep preparation, to prevent spinal distortion. If you fall asleep in semi-supine, it is likely that your lower back will flatten. However, if you consciously direct your spine to lengthen against the grounding of your feet, without holding any position, the sacrum should keep its healthy tilt within an un-tucked pelvis.

I do much of my sleeping flat on my back. If I roll onto my side, I avoid deep flexion of my legs so as to keep my trunk long and to maintain an easy lumbar curve.

If I’m cold, this one works for me: