Bone speed of sound, bone turnover and IGF-I in adolescent synchronized swimmers.

This pilot study compared bone speed of sound (SOS), bone turnover and insulin-like growth factor 1 (IGF-1) between 20 Caucasian, postmenarcheal, adolescent synchronized swimmers (SS) and 20 aged- and maturity-matched nonswimmers (NS). Daily dietary intake and physical activity levels were also assessed. Bone SOS was measured by quantitative ultrasound. Blood samples were analyzed for osteocalcin, cross-linked N-teleopeptide of type I collagen (NTx), IGF-I and 25-OH vitamin D. Although no differences in bone SOS or turnover markers were observed between groups, the lower IGF-1 and vitamin D intake found in synchronized swimmers, in combination with their higher strenuous activity levels, should be further explored.