Muscle Imbalance in Volleyball Players Initiates Scoliosis in Immature Spines: A Screening Analysis

STUDY DESIGN: Retrospective comparative study using radiographs and clinical findings. PURPOSE: To test the hypothesis that asymmetric loading of immature spines in young athletes initiates scoliosis. OVERVIEW OF LITERATURE: Scoliosis in athletes has been reported in the literature, but its causative factors have not been investigated. METHODS: We compared the incidence, type and magnitude of scoliotic curves in volleyball players with those in the non-player population. One hundred sixteen adolescent volleyball players were grouped for selective screening. Data regarding their playing duration, handedness, age, height, and menarchal status (in girls) were recorded, along with clinical examination and radiological investigation when necessary. We analyzed data from 46,428 non-player school children, and their data were compared to athletes to determine differences. RESULTS: Volleyball players had a statistically significant increase in the incidence of scoliotic spinal curves. Playing hand dominance was related to the curve direction. Cobb angle had no significant correlation with the duration of playing. CONCLUSIONS: There is a five-fold increase in the incidence of mild scoliosis in volleyball players. A high percentage (41%) of asymmetry was present on the Adams forward bending test, as compared to controls. The curves were either thoracic or thoracolumbar.