Bone mineral density in professional ballet dancers.

We studied the effect of physical training on the bone mineral content and soft tissue composition in 42 professional ballet dancers (17 men and 25 women). Twenty-eight of them were still actively performing and 14 had retired from professional dancing. Forty-two healthy age- and sex-matched volunteers served as controls. The bone mineral density (BMD) (g/cm2) in total body, spine, hip, arms, legs, and the proximal tibia metaphysis was measured with a Lunar DPX apparatus and the BMD of the distal forearm was measured with single-photon absorptiometry (SPA). Twelve of the now retired dancers had earlier been measured with SPA in the tibia condyle during their active career in 1975. There was no significant difference in BMD values between dancers and controls with the exception of a lower BMD in the head of the male dancers and a lower BMD in the arms of female dancers. After correcting for difference in body mass index (BMI), using analysis of covariance we found significant higher BMD in the lower extremities of female dancers and in the hip of male dancers. No correlation was found between the SPA measurements from 1975 and the corresponding measurements 15 years later. The dancers were on average 9 kg lighter but of the same height as the controls. The dancers had lower body mass index and fat content but their lean body mass was the same as the controls.