Bone assessment of female long-distance runners.

The objective of the present study was to investigate the effects of long-distance training on the bones in different growth stages by evaluating the bones of female high school athletes and female adult athletes who engage in long-distance training. Thirteen female high school athletes (aged 15-17 years) and 7 female adult athletes (aged 21-25 years) were enrolled in the present study. Bone mineral density (BMD) and bone mineral content (BMC) were measured using dual X-ray absorptiometry (DXA). Cortical bone status was also evaluated by measuring the tibial speed of sound (t-SOS). The bone metabolic status was evaluated by osteocalcin (OC) and tartrate-resistant acid phosphatase (TRAP). OC ( P < 0.01) and lumbar BMD ( P < 0.05) were significantly higher in high school athletes who were in the modeling period than in the adult athletes. Leg BMD ( P < 0.01) and t-SOS ( P < 0.05) were significantly higher in adult athletes who were in the remodeling period than in high school athletes. When lumbar BMD and leg BMD were compared according to menstrual conditions, the high school athletes with regular menstruation showed a significantly higher level of bone density than those having irregular or absent menstruation. These results indicate that the effect of long-distance training on bone metabolism is influenced strongly by sex hormones during late puberty. We concluded that the effect of long-distance training on bone metabolism in the female high school athletes (i.e., during puberty) was different from that in the adult athletes.