In the simplest of terms, core stability refers to the strengthening of muscles that support the spine and is a concept that underpins both the Pilates technique and current physiotherapy treatment of low back pain. A cylinder of muscles between the ribcage and pelvis helps to prevent the easily damaged joints, discs and nerves around the spine being overstretched as we move about. The muscles involved include
1. The deep abdominal muscle transversus abdominus, which forms the walls of the cylinder.
2. The pelvic floor, a hammock of muscles underneath the bladder and bowel, which form the floor of the cylinder.
3. The diaphragm, a dome shaped muscle under the ribcage which helps us to breathe and forms the roof of the cylinder.
4. Other muscles which attach to several levels of the spine, such as multifidus.
This muscles contract in a way that keeps a certain level of pressure within this cylinder , and this has a stiffening effect on the joints of the spine (much like a back support, but far superior because it is a dynamic brace which allows us to move rather than a static brace which holds us rigid). This stiffening effect minimises friction and excessive movement between the joints which minimises pain an the potential for wear and tear. in people with low back pain It is typical to see excessive movement in certain areas of the spine and excessive stiffness in other areas, and left unchecked this can lead to osteoarthritis. Furthermore, when core postural muscles are weak, other muscles which are designed for power more than endurance, work in their place becoming overactive and tight. An example of this would be somebody who has persistently tight hamstrings despite regular stretching. By retraining core muscles the muscle imbalance between weak postural muscles and overactive tight power muscles is restored, thus improving flexibility.