Inclusion Criteria:

1. Being 18 years or older;
2. Having current acute or sub-acute low back pain defined as pain that has not lasted more than 16 weeks;
3. Minimum score of 30mm on a 100mm visual analog pain scale.

Exclusion Criteria:

Exclusion criteria consisted of the following:

1. Have any of six possible un underlying causes of low back symptoms in their history (spinal osteomyletisosteomyelitis, spinal fracture, herniated disc, ankylosing spondylitis, cauda equina syndrome, or cancer, excluding nonmalignant skin cancer);
2. Have undergone surgery involving the low back; (
3. Have received workers’compensation benefits within the preceding year or were potentially involved in litigation relating to back problems;
4. Pregnancy, because of possible need for exposure to diagnostic x-rays;
5. Have participated as a subject in research previously at the trial clinic site;
6. Have received spinal manipulation within the preceding 3 months or on more than three occasions during the preceding year.

7. Subjects with sciatica were excluded if they had any one of the following:

   • Ankle dorsiflexion / plantar flexion weakness;
   • Great toe extensor weakness;
   • Absence of knee or ankle reflexes;
   • Loss of light touch sensation in the medial, dorsal, and lateral aspects of the foot;
   • Ipsilateral straight-leg-raising test (positive result: leg pain at <60°);
   • Crossed straight-leg-raising test (positive result: reproduction of contralateral pain).

   These six neurologic tests allow detection of most clinically significant nerve root compromises resulting from L4-L5 or L5-S1 disc herniations, which together make up more than 90% of all clinically significant radiculopathies attributable to lumbar disc herniations (21-25). Because approximately 12% of ambulatory patients with back pain h

8. Have symptoms of sciatica or leg pain without neurologic compromise related to lumbar disc herniation,[5] investigators attempted to include such subjects in the trial.

The criteria described above were intended to minimize the likelihood of including subjects with a lumbar disc herniation.