If you’ve had low back pain, you know how incapacitating it can be. One wrong step, and some mysterious stranger stabs a knife between your vertebrae. If you haven’t, and you’re practicing yoga, please read this article from My Yoga Online:
The one thing I would add is an insight from Leslie Kaminoff (again): the lower back does not twist. Really. There’s only 5ยบ of rotation possible in the lumbar spine. It just follows the direction of the sacrum. We can get a feeling of twist there, by engaging the abdominal muscles and feeling them wrap around the spine, but most of our twisting happens in the thoracic and cervical spine. So T11-T12 is a common place for injury, since it’s the first really rotating spinal joint. Make sure you’re spreading your twist throughout the spine.

