Reduced ultrasound velocity in tibial bone of young ballet dancers.

Young ballet dancers are at risk both for osteopenia, due to low body weight, inadequate nutrition and gonadal dysfunction, as well as for lower limbs stress fractures. However, a direct relationship between stress fractures and bone mass in dancers could not be demonstrated, raising the possibility that qualitative aspects of bone, such as elasticity, may be adversely affected in the dancers. To test this hypothesis, speed of sound, a physical parameter that reflects both quantitative and qualitative properties of bone, was determined at the tibial bone of 27 dance students and 27 non-dance students. The results were compared to bone mineral density at the tibia and the lumbar spine, measured by dual-energy x-ray absorptiometry. All three bone measurements were lower in the dance group, but the difference was statistically significant only for the tibial speed of sound. The role of tibial speed of sound measurement in assessing bone status in athletes warrants further exploration.