2.15 Scoliosis And Rhythmic Gymnastics P. Tanchev, A.Djerov, A.Parushev, D.Dikov University Hospital of Orthopaedics "Gorna Bania", 56, N.Petkov St., 1614 Sofia, Bulgaria. Phone: 00359 2 55 01 42; Fax: 00359 2 55 30 63 In a survey of 100 girls, aged 11-15, having been trained actively in rhythmic gymnastics at least for a period of 5 years, we found a fivefold higher incidence of adolescent idiopathic scoliosis (AIS). These data were compared to the results from a screening of 4800 students of the same age, carried out in Sofia by the same examining team in 1996. A detailed familial and past diseases anamnesis was registered in all the probands. General physical and meticulous back examinations were carried out, and X-rays were taken in all the AIS suspected cases. Special attention was paid to the presence of generalised joint hyperlaxity, which had been usually the main criterion for the primary selection of 5-year-old-girls to start training in rhythmic gymnastics. Eating regimen, weight-height relations, growth and maturing development (delayed menarche or secondary amenorrhea) were assessed too. Intensity, duration and specific moments of the training process were carefully analysed, and a significant asymmetric loading and an extreme physical overloading of the body were found. This study supports the multifactorial origin of AIS, and strongly suggests the important role of the following aetiologic triad in disturbing the growth of vertebrae and intervertebral discs: generalised joint hyperlaxity as a hereditary characteristic; delayed maturing caused by physical, dietary and psychic stresses; and persistent asymmetrical overloading of the growing spine. These findings in girls, practising rhythmic gymnastics, generate a hypothesis which needs to be juxtaposed on the characteristics of non-gymnast patients with AIS.