Although previous reports focus on the movement analysis and teaching technique, the risk of bone overuse osteopathy including stress fracture using serum blood sample remains unclear. The aim of this study was to investigate the changes in bone metabolism and quality markers during season in university skiers. Male university skiers (n=8, slalom and giant slalom) were tested at both the competitive season and the end of the relative rest period. Quantitative ultrasound of the right calcaneus, serum levels of bone alkaline phosphatase, N-telopeptide cross-link of type I collagen, tartrate-resistant acid phosphatase 5b, homocysteine, and pentosidine were measured. While no significant differences were observed between two points for quantitative ultrasound assessment, bone alkaline phosphatase, tartrate-resistant acid phosphatase 5b, homocysteine, and pentosidine, the levels of N-telopeptide cross-link of type I collagen at the competitive season was significantly higher in those at the end of rest period (p<0.05). Since N-telopeptide cross-link of type I collagen reflect the response of bone resorption, the present results reveal that bone resorption is expressly promoted at competitive season. We conclude that N-telopeptide cross-link of type I collagen is a useful marker for monitoring condition in male skiers. In addition, it may be important to prevent the overuse bone overuse osteopathy including stress fracture.
