The study, led by sports medicine researcher Anne Ho ch, D.O., at The Medical College of Wisconsin in Milwaukee, has been presented at the American College of Sports Medicine meeting in Seattle.

"These two components of the female athlete tetras put them at higher risk for the other two; the cardiovascular and bone density deficits of much older, postmenopausal women," according to Dr. Ho ch, associate professor of orthopedic surgery and director of the Froedtert and the Medical College Women’s Sports Medicine Center.

The researchers studied 22 professional ballerinas, all members of the Milwaukee Ballet Company, to determine the prevalence of disordered eating, amenorrhea (lack of menstruation), abnormal vascular function and low bone density.

The dancers completed questionnaires on their menstrual patterns and eating habits, and underwent a blood test for hormonal levels. Thirty-six percent of the group had disordered eating habits and 77 percent were in a calorie deficit. Twenty-seven percent were currently amenorrheic, 23 percent had low bone mass density and nine percent were taking birth control.rterial ultrasound measurements revealed that 64 percent had abnormal artery dilation in response to blood flow.

"It was unknown if professional dancers without menstrual periods have evidence of vascular dysfunction, yet some characteristics of the tetrad were common in this group," says Dr. Hoch.

"Eighty-six percent had one or more components, and fourteen percent had all four," the expert added.
References :
http://www.beealive.com/

Coordination
Balance
Strength
confidence
tone

Risks

You can brake a bone
feet problems
You have to be a certain size
Mean and strict ballet teachers
References :
The girl that I know weights from about 60-70 (she’s eleven)

Health Risks:
Gross Feet :]
Possibly breaking a bone like your ankle or toe

If you eat right and take care you won’t get skinny enough to miss your monthly gift! You really have to make sure you take care of your body when you do ballet because you will lose weight, but I don’t think you’ll get super skinny! I’ve never heard about ballerinas getting that skinny but it’s possible. Hope this helps!
References :
p.s. almost every ballet dancer at my academy weighs from 80-130 pounds or more! They’re not to skinny or to fat.

good:
gain muscles
coordination
balance

bad:
ugly feet, but thats the risk of dancing
References :