High-impact loading training induces bone hyperresorption activity in young elite female gymnasts

The aim of this study was to investigate the effect of intensive exercise o n bone turnover (as reflected by bone resorption) in young elite female gym nasts. Forty-five healthy girls including 24 gymnasts (11.9 +/- 2 yr) and 2 1controls (12.3 +/- 1.4 yr) were studied. Body weight, height, bone age and body composition were measured. Bone mineral density (BMD) was assessed at the whole body, lumbar vertebrae, hip and radius by means of DXA, Volumetr ic density (BMAD) was calculated, Bone velocity (SOS) and attenuation (BUA) were measured by QUS at the calcaneus, Urinary androstenedione (Delta (4)) , dehydroepiandrosterone sulfate (DHEA-S), and CrossLaps (CTx) were measure d. BMD and BMAD were significantly greater in the gymnasts at all sites exc ept whole body. SOS was found significantly higher. Delta (4) values were s ignificantly lower in the gymnasts. The distribution of the subjects accord ing to Tanner stages was not different between groups. CTx levels were sign ificantly higher in the gymnasts (989.08 +/- 154.63 mug/ mmol Cr.) vs contr ols (580.25 +/- 123.99 mug/mmol Cr., p=0.02), CTx values decreased from Tan ner stage 1 to stage 4 in each group, the gymnasts' levels always being hig her than those of the controls. In conclusion, gymnastics seems to stimulat e bone resorption activity in highly-trained young females. The coexistence of bone hyperresorption and higher BMD in gymnasts suggests increased bone turnover resulting in increased bone density in these subjects.