[Stress fractures. Spondylolysis and spondylolisthesis of the lumbar vertebrae among young athletes with back pain].

Frequency of spondylolysis is higher among athletes who perform movements involving repeated flexion and extension of the spine than in the normal population. This article describes 50 patients (30 women, 20 men) with spondylolysis/spondylolisthesis grade 1 who were examined at the Norwegian Institute of Sports Medicine. Handball, followed by soccer, were the dominating sports in our study. Most of the patients were 15-19 years old; 20 patients had had low back pain for more than 12 months from onset till the first examination. In 45 patients the defect was found in the fifth lumbar vertebra, in three in L3 and in two in L4. This study indicates that stress fracture is the most dominating cause of spondylolysis in athletes.