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The Female Athlete Triad: The Importance of Energy

  • 10/20/2011 8:42:00 AM
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The Female Athlete Triad: The Importance of Energy

 Kaleigh Camp, M.S.

The American College of Sports Medicine refers to the female athlete triad as the interrelationships among energy availability, menstrual function, and bone mineral density. The new Triad model has each component of the female athlete triad on a continuous spectrum. These spectrums range from a healthy state to clinical outcomes of disease, which including eating disorders, amenorrhea (absence of a menstrual period for 3 or more months), and osteoporosis. This interrelationship can be observed in the figure below which came from the American College of Sports Medicine: Position Stand of The Female Athlete Triad. 
The first component of the Triad is energy availability. Energy availability can be defined as energy intake minus exercise energy expenditure. Low energy availability can occur by not consuming enough calories or by burning more calories during training than one consumes. This decreased energy availability can occur with or without an eating disorder and usually impacts female athletes in sports that stress lean body phenotypes, like cross country runners and gymnasts. Low energy availability is significant in the Triad, because it can negatively impact both reproductive and skeletal health and thus both present and future health outcomes.

Menstrual function is the next component of the Triad. Typically, female athletes’ menstrual function ranges from eumenorrhea (normal menstrual function) to amenorrhea, although they can suffer from irregularities found in the general population.  Some female athletes may feel that losing their menstrual cycle is normal due to their intense training schedule; however, this abnormal development in menstruation (decreased estrogen status) can lead to drastic bone loss. Some female athletes are prescribed oral contraceptives to make their menstrual cycle more regular and to possibly improve their bone health; however, research has shown that these birth control pills are not the best solution because they may not improve bone outcomes and they do not address the most plausible underlying problem: ENERGY.




Decreased energy availability and the disruption of menstrual function can have significant impacts on bone health, which is the third component to the Triad, and can potentially lead to poor bone outcomes like osteopenia or even osteoporosis. Both of these disorders refer to decreased bone mass and bone brittleness. The only difference is a diagnosis of osteoporosis means a more severe amount of bone loss. Ihle and Loucks’ pivotal research demonstrated that when energy availability is decreased enough to suppress estradiol, a form of estrogen, levels it can lead to irregular bone turnover in just 5 days! If continued then irreversible reductions in bone mineral density could occur.


Increasing the knowledge of female athletes about the Triad is an important first step to preventing these serious health problems. A proper diet that consists of the adequate number of calories and the appropriate intake of calcium (1,200 mg/day for young women) is the best line of defense to avoid reductions in energy availability that can directly affect bone and reproductive outcomes.  The main goal is to encourage female athletes to reach top performance and to understand that physical activity is encouraged for a healthy lifestyle without forgetting the importance of good nutrition.

References and for further readings related to this topic:
  1. American College of Sports Medicine Position Stand: “The Female Athlete Triad” Medicine & Science in Sports & Exercise: October 2007 – Volume 39 –Issue 10 –pgs 1867-1882.
  2. Ihle, Rayan and Loucks Anne. “Dose-Response Relationships Between Energy Availability and Bone Turnover in Young Exercising Women.” Journal of Bone and Mineral Research: November 2004 – Volume 19:8.
  3. Zach, Karie N; Smith Machin, Ariane L; and Hoch, Anne Z. “Advances in Management of the Female Athlete Triad and Eating Disorders. Clinics in Sports Medicine: July 2011—Volume 30—Issue 3—pages551-573.
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