Lumbosacral or lumbar segmental instability (LSI) is a name to describe a specific problem in the spine. It’s one of several subgroups of patients who have low back pain.
The actual problem is one of too much motion between two vertebrae. Mechanical overload is blamed for the loss of stiffness that occurs. Using the spine over and over with too much force can cause LSI.
Researchers have found one way to treat LSI is with spinal stabilization exercises. These exercises train the muscles to contract in ways that increase spinal stability.
When muscles on both sides of the vertebrae contract at the same time it’s called cocontraction. Exercises to promote patterns of cocontraction seem to help stabilize the spine and reduce pain for patients with LSI.