Stress injury to bone in the female athlete.

Stress injury to bone exists on a continuum, involving mechanical as well as hormonal and nutritional factors. Risk factors for stress injury include genetics, female gender, white ethnicity, low body weight, lack of weightbearing exercise, intrinsic and extrinsic mechanical factors, amenorrhea, oligoamenorrhea, inadequate calcium and caloric intake, and disordered eating. Prevention of stress injury to bone involves maximizing peak bone mass in the pediatric, adolescent, and young adult age groups. Maintaining adequate calcium nutrition and caloric intake, exercise and hormonal balance are important preventive measures in the adult years for optimizing skeletal integrity and preventing fractures. There are no prospective longitudinal studies to date that demonstrate a treatment that will increase bone density in female athletes with hypothalamic hypoestrogenic amenorrhea or disordered eating that have low bone density. Advances in genetic research show promise for future preventive and treatment strategies. More research is needed in this area to determine other factors that may be contributing to bone loss in these individuals, as well as to assess other treatment options leading to improvements in bone density and integrity.

Nutrition Supplements: Science vs Hype.

Aggressive marketing has led millions of recreational and elite athletes to use nutrition supplements in hopes of improving performance. Unfortunately, these aids can be costly and potentially harmful, and the advertised ergogenic gains are often based on little or no scientific evidence. No benefits have been convincingly demonstrated for amino acids, L-carnitine, L-tryptophan, or chromium picolinate. Creatine, beta-hydroxy-beta-methylbutyrate, and dehydroepiandrosterone (DHEA) may confer ergogenic or anabolic effects. Chromium picolinate and DHEA have adverse side effects, and the safety of the other products remains in question.