OBJECTIVES: Bone turnover marker changes in response to physical activity are well documented. There is, however, little information on the extent and severity of skeletal de-conditioning in athletes in response to rest periods. This study analyses changes in markers of bone resorption and bone formation during the close season within the squad of an English Football Association Championship club.
DESIGN: Evaluation was performed on the first team football squad just before the end of the 2007/2008 football season and again 8 weeks later before pre-season testing and training.
METHOD: Bone resorption was measured by serum concentration of C-terminal telopeptide (CTx) and bone formation by serum concentration of the N-terminal propeptide of type I procollagen (PINP). Twenty football players aged from 18 to 36 years (mean 23.6 years) were included in the study.
RESULTS: The mean change in CTx during the close season was +0.14 ng/ml (95% CI: 0.21 to 0.06, p=0.001). The mean change in PINP was -10.8 ng/ml (95% CI: -3.9 to -17.7, p=0.004).
CONCLUSIONS: In professional football players, a close season rest of 8 weeks results in an increase in bone resorption and a decrease in bone formation markers. This imbalance between formation and resorption may have negative effects on bone mass and structure. Future research should focus on understanding the many factors that could contribute to the changes found in the study during the close season.