Calcium & Female Athletes

Adequate calcium intake is especially important for female athletes exercising seven or more hours a week. Exercise at this level — especially for girls in puberty — can cause hormonal declines, which can lead to compromised bone formation and premature osteoporosis. The recommended dose is 1,200 to 1,500 mg a day. (One cup of skim milk provides about 300 mg of calcium.)
-British Journal of Sports Medicine, September 1996