This study will seek to determine if 1) the manual unloading test is reliable, and 2)if the immediate response to traction can be determined by using a simple unloading test in standing. The study wil be completed in two parts: 1) a small pilot sample (n=10) to asses both intra and inter tester reliability, and 2) a consecutive sample of 30 patients with low back pain which does not travel below the knee. All subjects will rate their pain on a 100 mm line both at rest and in their most painful direction of movement. A therapist will then unload the patients spine to determine if they feel any relief. All subjects will then undergo a 15 minute bout of intermittent lumbar traction, 30 sec on, 10 sec off at up to 50% body weight. Following traction, all subjects will again rate their pain on a 100 mm line. Subjects will be grouped by response to the initial manual unloading test and assessed for within and between group differences. The study hypothesis is that the manual unloading test is reliable, and that responders to mechanical traction can be accurately identified using a manual unloading test.