Question

it has been noted that in some ballet dancers that the bone density is greatly reduced compared to that which is seen in average population. suggest reasons for this with an explanation of how bones are affected by diet, hormones and excercise.

Answer 1

Ballet Dancer have reported to have delayed menarche and amenorrhoea which are responsible for low bone density. Also the continuous mechanical stress on the body leads to lower bone density in the spinal region of the ballet dancers. Non Weight bearing sites have less or no variation in bne density as compared to the non-ballet dancers. Ballet training has positive effect on bone density on weight bearing sites such as hip. Femoral neck of the hip has equal or greater bone density in the ballet dancers.

The onset of puberty and menarche are very essential for the proper bone density development in the adolescents. Early onset of puberty and regular menses is associated with greater lumbar spine and total bone mineral density as compared with girls having irregular menses. Ballet dancers have reported irregular menses and even delayed menarche. This results in lowering of the bone density in ballet dancers. Pre-puberty stage is prelonged in dancers undergoing intensive training.

The long term impact of amenorrhea combined with intensive training leads to stress induced fractures in professional dancers. Amenorrhea is also found to be prolonged in the dancers. It reduces the bone density in the regions of lumbar spine and the arms.

To remain in a proper shape and to stay fit, professional dancers resort to extreme diet and usually fall prey to eating disorders like bulimia or anorexia nervosa. These disorders effect the over all health of the dancer. Calcium intake decreases and the body undergoes complusive starvation. All of this leads to osteoporosis along with many other diseases like diabetes, erosion of enamel etc.

Thus we can see that intensive ballet excercises leads to lowering of the bone density and stress induced fractures. To avoid the excessive training should be avoided, proper diet including sufficient amount of calcium should be provided. Vit D levels should be monitored regularly. Proper rest should be taken by the dancers to avoid fractures and over strain. Muscle relaxation and massage must be performed during intensive exercising.