Clinical trial of intensive muscle training for chronic low back pain.

105 patients who had chronic low back pain without clinical signs of lumbar nerve root compression or radiological evidence of spondylolysis or osteomalacia were randomised to three treatments: 30 sessions of intensive dynamic back extensor exercises over three months; a similar programme at one-fifth the exercise intensity; or one month of thermotherapy, massage, and mild exercises. The results consistently favoured intensive exercise, which had no adverse effects. Since these exercises can be conducted in groups, the intensive programme is no more costly than conventional strategies that require individual attention.