| Summary: | 碩士 === 國立臺灣體育運動大學 === 運動健康科學系碩士班 === 99 === Weightlift is a high weight-bearing exercise and had through to be benefit for bone health. However, if the train program and rest time did not deploy properly, may increase the risk of fracture injury. Besides, numerous studies have shown weight loss quickly may have negative effect of bone metabolism in weight class athlete, which hormone homeostasis such as leptin level also altered while body composition changes. Recent evidence suggests that leptin may play a role in bone metabolism. The effects of leptin and weight-bearing type during exercise training changes on bone metabolism remained uncertain. Therefore, the purpose of this study is to evaluate bone metabolic changes and effect of leptin during training session on weightlifters, or by other bone regulatory hormones mediate the effect of physical activity on bone . Eleven male weightlifters aged 22-23 years old were recruited from top ranked College weightlifter team in Taiwan. During the training session, all subjects were asked to follow the training program previously designed by coach. Fasting blood sample were collected in early morning at the day 1, 15, 35 and 55 of the training session. Bone cytokine OPG and RANKL, and bone specific biochemical markers including Osteocalcin, B-ALP, beta-crosslaps, and bone regulatory hormones Leptin, PTH, Testosterone, and Cortisol were analyzed to evaluated bone metabolic status. Weekly training volume and anthropometric parameter were recorded by questionnaires. Training volume kept reducing since beginning of this study according to pre-design training program. Body weight and fat mass were not significantly changed. Free fat mass on day 35 and 55 significant increased. Leptin level were slightly increased on day 35. PTH level were increased significantly on day 55. Testosterone and Cortisol level were decreased on day 35 and returned to basal level since day 55. OPG level were slightly increased on day 55. sRANKL were not significantly changed. B-ALP level were slightly increased on day 15. Osteoclacin and beta-crosslaps level were decreased significantly on day 35 and returned to basal level since day 55. Correlations between Leptin and bone parameters, Leptin （Δ23） was positively associated with OPG （Δ34） and sRANKL （Δ34）. Leptin （Δ23） was negatively associated with Osteocalcin （Δ23） and Beta-crosslaps （Δ23）, and Leptin （Δ23） was positively associated with B-ALP （Δ34）. Results of present study indicated that bone mineralization and bone resorption were correlated to training volume while bone formation was not. Leptin concentrations increased was produced bone protective effect in early training session, to promote osteoblast precursors growth and differentiation indicated of bone formation increased in the late training session. And exercise intensity increased at the late training session, brought mechanical loading caused both osteoblast and osteoclast reactivation with Leptin delay effect of early training session combined effect of bone metabolism. Exercise product mechanical loading return regulation of bone metabolism.
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