In Sweden, the National Social Insurance Offices (a government agency running the mandatory national social insurance scheme applicable to all Swedish residents) handle sick leave with a duration of two weeks or more. They as well as general practitioners (GP) and other physicians referred patients. The recruiting physician examined all patients, performed a physical examination, and made the final assessment whether they fulfilled the inclusion criteria. Of the 316 patients who were referred to the study, 111 did not meet the inclusion criteria and 45 declined participation. The 160 patients that gave informed consent were entered in the study. After baseline evaluation they were randomized by the study monitor, using sealed pre-prepared envelopes with group assignment derived from a random number table. The envelopes were inaccessible to anyone but the monitor. A design with four treatment groups was used: two experimental and two reference groups with treatment items added successively. The two-group comparison (reference vs experimental treatment) was the primary planned analysis, and pain, disability rating and sickness absence were the main outcome measures. A weighted randomization procedure was used, with 45% of the patients to reference and 55% to the experimental therapies. The Research Ethics Committee at Uppsala University approved the study.