175 patients who were unable to work due to back pain were treated. After eight inversion treatments, 155 patients were able to return to their jobs full time. Study concluded that the main basis for improvement was the stretching of paraspinal vertebral muscles and ligaments and possibly the widening of intervertebral discs. Study found significant improvements in a variety of diagnosis including spondylolisthesis, herniated discs, lumbar osteoarthritis with sciatica, and coccygodynia. Patient experienced traction in a modified hip flexed position.

Study found EMG activity (an indicator of muscle pain) declined 35% within the first 10 seconds of inversion. Study found that inversion increases the spinal length. Study concluded there is a correlation between a reduction in EMG activity and an increase in spinal length.

Study found all subjects experienced intervertebral
separation in the lower lumbar vertebrae. Study concluded that although mechanical traction has been used for centuries, only gravity assisted traction (inversion) offers an effective means of achieving pelvic traction at home.

Study found a general reduction of EMG (an indicator of muscle pain) after three minutes of inversion. Study found the flattening of the lumbar spine involved a stretching of spinal muscles and ligaments which lead to a 25% increase in forward spinal flexion. Study found significant intervertebral separation (posterior and anterior). Study concluded that an inversion chair may be sufficient to reduce the majority of intervertebral disc protrusions. Study concluded that the cardiovascular system (heart rate and blood pressure) remained stable through three minutes of seated partial inversion. Authors conclude this stability is due to the full comfort and support of the chair during partial inversion.

Study stated the hip flexed position facilitates lumbar traction by flattening the lumbar spine and decreasing the loading effect of the psoas muscle on the lumbar spine during traction. Study stated inversion therapy is preferred over mechanical traction because there is no need for a constricting harness and the safe and simple operation of an inversion chair allows the patient to administer traction. Study stated inversion helps to negate the effect of gravity on the spinal column. Study stated inversion offers promise as a form of prevention, maintenance, and therapy.