Wikipedia States that:
Traction and stretching
When the body's weight is suspended from the lower body – rather than borne on the hands as in handstands or headstands or hanging from a bar with arms at sides, which are also forms of inversion – the pull of gravity may decompress the joints of the body below the anchor. 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. Inversion therapy of this sort is often commercially advertised as a relief for back pain, but it is not widely regarded as a serious treatment.
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 gravity-related pressure is removed, the 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 the intensity and duration of traction can cause stimulation for the strength of ligaments to increase.
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. As misalignment of the hips and spine can itself be a source of inflammation and pain, this is another argument for traction as a back therapy.
Inversion devices are promoted as a tool to be used in gaining flexibility. Static-active stretching methods impossible to perform while 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).
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 compared to standing 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 normally above the heart.
People who have heart disease, high blood pressure, eye diseases (such as glaucoma), or are pregnant are at higher risk for the dangers related to inversion therapy and should consult their doctors about it first. Such people would have to progress very slowly, starting at very light levels of inversion. The first time anyone tries inversion therapy with gravity, they should be sure to have someone standing by, in case assistance is required to get out of the apparatus, or if health problems are experienced.
]In popular culture
In the CBS sitcom Gary Unmarried, Jay Mohr, who plays the title character, treats back pain in season 1, episode 2, "Gary Gets Boundaries"
TV star Rosie O'Donnell has said that she uses inversion therapy to treat her depression.
Inversion therapy is used by Richard Dean Anderson's title character in the 1980's television series MacGyver.
Writer Dan Brown has told fans he uses inversion therapy to help overcome writer's block.
The character Agent Cooper is shown engaging in inversion therapy on at least one occasion in David Lynch's cult television series Twin Peaks.
In the 1989 movie Batman, Michael Keaton (Batman) is seen hanging upside down wearing inversion boots.
In the 1990 movie Back to the Future Part II George McFly (Jeffrey Weissman) is hanging upside down.
In the 1991 movie Cape Fear, Max Cady (Robert De Niro) is seen hanging upside down wearing inversion boots
In the 1999 movie Deuce Bigalow: Male Gigolo, both Oded Fehr (Antoine Laconte) and Rob Schneider (Deuce Bigalow) are seen hanging upside down wearing inversion boots.