Bone Mineral Densities in Ballerinas, Korean Traditional Dancers and Athletes

Park, Jin Young; Lee, Sung Churl

Abstract

Evidence in human studies of the association of long term habitual exercise with bone mineral content (BMC) and bone mineral density (BMD) mostly come from studies done on athletes. The highest BMC and BMD values in young adults have been found in strength and power-training athletes, while endurance activities such as long distance running and swimming seem to be less effective in obtaining peak bone mineral density. To compare the differences in BMD among ballet, Korean traditional dancing and athletics, we examined the BMD of 10 ballerinas, 10 Korean traditional dancers, 12 athletes and 12 volunteers as the control group. All participants were female. The average age were 20.6 years for the ballerinas, 21.2 for the Korean traditional dancers, 20.4 for the athletes and 21.3 for the control group. Average weights were 50.6 kg for the ballerina, 53.7 kg for the Korean traditional dancer, 59.2 kg for the athletes and 53.8 kg for the control group. Average heights were 162.0 cm for the ballerinas, 160.4 cm for the Korean traditional dancers, 162.3 cm for the athletes and 160.5 cm for the control group. There were no significant differences in the BMD values of the proximal femur and the lumbar spine between ballerinas and control group and between Korean traditional dancers and control group (p>0.05). There was, however, a significant increase of BMD in the proximal femur and lumbar spine of the athletes when compared with the control group (p<0.05) After adjusting for difference in body mass index (BMI) we recompared the BMD of ballerinas, Korean traditional dancer and athletes with BMD of control group and found significant higher lumbar spine BMD values in ballerinas, Korean traditional dancers and athletes. In athletes higher BMD levels were also obtained in the proximal femur including the neck, greater trochanter and Wards triangle regions (p<0.05). There was no significant increase of proximal femur BMD levels for Korean traditional dancers (p>0.05). Differences of BMD values between the ballerinas and control group was statistically significant only in femoral neck (p<0.05).