Loads in the lumbar spine during traction therapy.

The purpose of the present study was to determine the loads acting on the lumbar spine when traction therapy was given in the Fowler's position. The study had two parts: a theoretical analysis which showed that traction produced a flexion moment on the spine as well as axial distraction; and an experimental study which measured the flexion moment induced by the adoption of the Fowler's position. The Fowler's position is clinically essential in that it flexes the spine and takes up the slack of the posterior tissues before the traction force is applied. Hence the axial tension and flexion moment generated by the traction force are more effective in stretching the posterior tissues. The angle of pull on the traction harness influences the friction between the body and the couch. However, this consideration is not necessary if a split traction table is used. The mechanical effects of traction are compared with those produced by postero-anterior mobilisation. The relative magnitude and direction of loads produced, and their variation with segmental level should be considered by therapists when choosing a technique for treating low back pain.