Body Mass, Training, Menses, and Bone in Adolescent Runners: A 3-yr Follow-up.
Barrack MT, VAN Loan MD, Rauh MJ, Nichols JF. Med Sci Sports Exerc. 2011 Jun;43(6):959-66.
Among 40 adolescent female endurance runners, 15 females were defined as low bone mass at baseline (~16 years old) and 87% of those females still had low bone mass after 3 years. This highlights the need for sports medicine clinicians to recognize a problem that can lead to long-term consequences (e.g., osteoporosis) and try to emphasize behaviors that promote bone mineral during early adolescent years.