Yoga movements may help relieve back pain more than other types of exercise, a new study suggests.

"Although exercise is one of the few proven treatments for chronic low back pain, its effects are often small and we haven't known whether one form is better than another," said Karen Sherman of the Group Health Cooperative Center in Seattle. "So we designed a study to evaluate the effectiveness and safety of a gentle program of yoga for people with this condition."

Sherman and her colleagues randomly assigned 101 adults with low back pain to either

• 12 weekly, 75-minute classes to learn yoga and practise at home.
• 12 weekly, 75-minute sessions of aerobic, strengthening, and stretching exercise, plus home practice.
• A self-care book on back pain.

Sherman and her colleagues found people with low back pain who practised yoga for three months had an easier time using their back for daily activities compared to those who were in the exercise or education groups.

All participants could use drugs for back pain when needed. After six months, those in the yoga group also used fewer pain relievers, the researchers report in the Dec. 20 issue of the Annals of Internal Medicine.

Current treatments for low back pain include pain relievers, painkillers, muscle relaxants and exercise.

The students learned 17 movements, including viniyoga, an easy-to-learn, therapeutic style that focuses on breathing and can be adapted for various body types.

It's estimated one million people practise yoga for relief of back pain in the U.S., according to national surveys cited in the journal.

Sherman recommends choosing an instructor who is experienced in leading people with low back pain. Successful treatment also requires patients to practise at home.