There are various methods of traction therapy, but one of the most common for lower back pain or sciatica, is for the patient to lie on a traction bed and to have have graded weights fixed onto the legs and a harness to the upper body to keep the patient in position. As the weights are applied the spine is pulled and stretched, The idea is that this makes the displaced spinal disc start to reposition itself. Also it is thought that muscles which are in tension will benefit by the stretching and that tension will be relieved.