Inversion is the practice of thinking through problems in reverse. It's asking how an endeavor could fail, and then being careful to avoid those pitfalls. This idea comes originally from algebra, where an equation is oftentimes easier to solve if you invert it.
In theory, inversion therapy takes gravitational pressure off the nerve roots and disks in your spine and increases the space between vertebrae. Inversion therapy is one example of the many ways in which stretching the spine (spinal traction) has been used in an attempt to relieve back pain.
