Therapeutic exercise has been shown to benefit patients with chronic back pain. However, the effect is modest, and it is not known if certain types of exercise are more effective than others. Yoga may have advantages over other exercise interventions because it emphasizes relaxation and increases mental focus. Sherman and colleagues compared how yoga, therapeutic exercise, and a self-help book affected chronic low back pain.

The randomized controlled trial included adults who were diagnosed with low back pain in the Washington State and Idaho Group Health Cooperative. They were recruited via health plan magazine advertisements and direct mailings. Patients were excluded if they reported minimal pain (0 to 2 points on a severity scale, with 10 being the highest level of pain) or if a specific underlying condition was the confirmed or likely cause of pain. Patients also were excluded if they were receiving physical therapy for back pain, had serious medical or psychiatric conditions, or had work schedules that were incompatible with the class schedule. The 101 participants were predominantly women (66 percent), white (80 percent), had some college education (97 percent), and were employed (87 percent). Sixty-seven percent of participants reported pain lasting more than one year.

Participants were randomly assigned to an intention-to-treat intervention (i.e., 12 75-minute weekly yoga classes, 12 weekly 75-minute exercise classes, or an evidence-based self-help book containing strategies for managing back pain). One instructor led each of the exercise and yoga classes. Yoga classes consisted of breathing exercises, a sequence of postures designed to relieve low back symptoms, and guided relaxation. Exercise classes consisted of gradually increasing aerobic repetitions and strengthening exercises followed by stretching. Participants who received self-help books had no instructions and did not attend classes. Information about functional status, which was based on a 24-point Roland Disability Scale, and on symptom severity, which was based on an 11-point “bothersomeness” scale, was gathered by telephone interviews at six, 12, and 26 weeks. Participants in the yoga and exercise groups had similar class attendance with participants attending nine of the 12 classes, on average. Eighty-seven percent of participants in the self-help group reported reading at least one third of the book. Ninety-five participants completed the 26-week interview.

Although functionality and symptom severity improved in all groups, the yoga group had the best results. At 26 weeks (14 weeks after the completion of classes), the yoga group's mean disability score was 3.6 points lower than that of the self-help group and 1.5 points lower than that of the exercise group (2.5 points was considered clinically significant). Similarly, the yoga group's mean symptom score was 2.2 points lower than that of the self-help group and 1.4 points lower than that of the exercise group (1.5 points was considered clinically significant). In addition, reported pain medication use in the week preceding the week 26 interview was significantly lower in the yoga group (21 percent) than in the exercise group (50 percent) or self-help group (59 percent).

The authors conclude that yoga was more effective than a self-help book for treating chronic low back pain, producing clinical benefits at least equivalent to, and possibly better than, traditional therapeutic exercise. They caution that participants' baseline demographics and the study's relatively short follow-up period may limit these findings.