160 Anatomy & Physiology Essentials Copyright Goodheart-Willcox Co., Inc. cause negative health consequences ranging from irreversible bone loss to death, friends, parents, coaches, and physicians need to be alert to the signs of this condition. Female athletes participating in endurance or appearance-related sports are most likely to be affected by the female athlete triad. Disordered eating can take the form of anorexia nervosa or bulimia nervosa. Symptoms of anorexia nervosa in girls and women include a body weight that is 15% or more below the minimal normal weight range, extreme fear of gaining weight, an unrealistic body image, and amenorrhea. Bulimia nervosa involves a minimum of two eating binges per week for at least three months an associated feeling of lack of control use of self-induced vomiting, laxatives, diuretics, strict dieting, or exercise to prevent weight gain and an obsession with body image. The most common symptom of osteoporosis, how- ever, is back pain derived from crush-type fractures of the weakened trabecular bone of the vertebrae. These fractures can be caused by activities as simple as picking up a bag of groceries or a bag of trash. Vertebral crush fractures frequently cause reduction of body height and tend to accentuate the kyphotic curve in the thoracic region of the spine. The Female Athlete Triad Unfortunately, osteoporosis is not confined to the elderly population. It can also occur in female athletes at the high school and collegiate levels who strive to maintain an excessively low body weight. Striving for an extremely low weight can cause a dangerous condition known as the female athlete triad. This condition involves a combination of disordered eating, amenorrhea—having no period or menses—and osteoporosis. Because the triad can Bone Density in Female Athletes Regular weight-bearing exercise can increase bone mineral density (BMD). Alternatively, maintaining a body weight that is 15% or more below the normal range can lead to reduced BMD, which can result in osteoporosis at an early age. Females across numerous sports maintain a relatively low body weight and also engage in regular training that involves weight-bearing impacts, including running and jumping. What effect does this have on bone density among female athletes? One group of researchers posed this very question in a study involving 239 female athletes participating in 16 college sports. The researchers measured the athletes’ heights and weights to calculate body mass index (BMI). The participants also had dual-energy X-ray absorptiometry (DXA) scans and were screened for female athlete triad risk. The results showed that the teams with the lowest BMDs were synchronized swimming, swimming/diving, crew/rowing, and cross-country. The highest values were in gymnastics, volleyball, basketball, and softball. Across sports, those athletes with triad risk factors had lower BMDs. When accounting for triad risk and BMI, the high-impact sports were associated with higher BMD scores and the nonimpact sports with lower BMDs. What do these findings mean? Lower BMDs were expected in athletes participating in non-weight-bearing sports, including the swimming and rowing events. Higher BMDs were expected in sports involving jump landings, including gymnastics, volleyball, and basketball. The softball athletes had higher BMDs because of higher BMIs compared to other groups. The cross-country athletes had lower BMDs because of lower BMIs. This same result for female cross-country athletes was confirmed in a different study that measured percent body fat and BMD. Skeletal health, then, is related to weight-bearing exercise, but also to maintaining a healthy body weight. Research Notes lzf/Shutterstock.com It is important for female cross-country athletes to maintain a healthy body weight to avoid low bone density.