Inversion therapy involves hanging upside down or at an inverted angle with the intention of therapeutic benefits. It, however, is rarely regarded as a serious treatment for back pain.
Hanging by the feet, as with gravity boots or inversion tables, causes each joint in the body to be loaded in an equal and opposite manner to standing in an identical position of joint alignment.
Proponents claim that inversion therapy is particularly beneficial for the spine in that it relieves pressure on the discs and nerve roots; this in turn allows discs to recover lost moisture and to return to their original shape, decreasing the pressure they can exert on nerves. Skeptics note that pressure is also relieved when lying down in bed. Proponents counter that while pressure is removed, pressure of tight muscles is not, and that traction is needed to allow the possible space between spinal discs to be realized.
Holding the bones of the spine and legs together, the ligaments crossing the joints under traction are subjected to pulling forces, assisted by passive muscle tension, the skin, and the fascia. Proponents claim gradual introduction and increases (of intensity and duration) of traction could cause stimulation for the strength of ligaments to increase.Posture Proponents advocate that traction can be a tool to restore proper alignment to the spine, which may assist in maintaining proper posture when later righted.Flexibility Inversion devices are promoted as a tool to be used in gaining flexibility. Static-active stretching methods impossible to perform standing can be performed upside down for the spinal flexors, side flexors and extensors, and situps are a closed-chain exercise for the hip flexors (a static-active stretch for the hip extensors) compared to the upright exercise, leg raises, which are open-chain movements. Due to increased spacing in the joint which can occur in response to traction, the muscles crossing that joint are pre-stretched, and as such, experience a greater lengthening compared to the equivalent joint angle while under no traction (lying down) or while being compressed (standing). Blood flow Claims are made that inversion stimulates circulation differences due to gravity acting on the circulatory system in an opposite manner, opposing what it would normally assist, and assisting what it would normally oppose, while upright. This pooling of blood and greater circulation is thought by some to increase oxygen flow to those tissues, primarily in the brain or roots of the hair, which are superior to the heart.