Publication:

舉重運動員補充HMB對骨質代謝之影響

於長時間的訓練過程中，運動員經常藉由補充各式各樣的營養補充品以提升訓練效果，並修補恢復運動時所受到的各種傷害，進而防範可能發生的重大運動傷害，如疲勞性骨折等須長時間復原的傷害。β-羥基-β-甲基丁酸(beta-hydroxy-beta-methylbutyrate, HMB)目前已被廣泛用來提升肌力、增加骨骼肌含量與提升疲勞恢復等，近年來的研究則指出，HMB可能具有影響骨質代謝之作用，因此本研究欲探討舉重運動員在長期訓練中補充HMB後，對骨質代謝產生的影響；探討補充HMB後，對於血液中骨質代謝指標與單核前驅細胞內細胞蛋白的影響。自國立臺灣體育運動大學舉重代表隊招募16名健康的男性受試者，分為補充HMB組與補充安慰劑組。於為期一個月的訓練週期內，每天補充3 g HMB，並紀錄飲食狀況與填寫運動回顧問卷，訓練強度根據由教練所指示之訓練計畫，每週進行採血。分析血液中骨調控細胞激素OPG (osteoprotegerin)與sRANKL(soluble receptor activator of nuclear factor κB ligand)，骨骼代謝指標B-ALP(bone-specific alkaline phosphatase)、osteocalcin與beta-crosslaps，血液荷爾蒙PTH(parathyroid hormone)與cortisol，血液單核球中的細胞蛋白IκB-α (nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha)與單核細胞膜上的receptor activator of nuclear factor κB (RANK)。結果顯示，骨合成指標B-ALP顯著且持續上升至訓練期結束，且於第三週組間達顯著差異；osteocalcin則兩組皆呈現明顯上升之趨勢，然組間並無明顯差異；骨分解指標beta-crosslaps，HMB組四週皆無明顯變化，placebo組則呈現持續上升之趨勢，並於後兩週達顯著；PTH兩組於後兩週皆明顯的上升，然組間並無顯著差異；cortisol於HMB組第一週達顯著上升後，隨後恢復至訓練前水平；sRANKL兩組呈現出不同的變化趨勢；OPG與訓練量呈現出相似的變化趨勢，RANK於placebo組第一週達顯著性的上升，隨後恢復至訓練前水平；IκB-α兩組自第一週起即顯著的下降，placebo組維持第一週水平至訓練結束，而HMB組則持續下降至訓練期結束，並於第四週兩組達顯著性差異。本研究主要發現，舉重選手於為期四週的訓練週期中，每日補充3克HMB，除了因訓練所提升骨質礦化作用外，還能額外提升造骨細胞的活性，提高骨質的合成作用；另一方面能有效減少，由運動刺激所造成的骨質分解作用。

Recently, beta-hydroxy-beta-methylbutyrate (HMB) is one of the dietary supplements promoted to enhance gains in strength and lean body mass associated with resistance training. Besides, some animal studies indicate that HMB may have the relationship with bone metabolic. Thus this research aims to discuss the effects of HMB supplement on bone biomarker in weightlifters during the training session. Sixteen healthy male weightlifters were recruited from university weightlifting team, and divided into two groups. During the training session, all subjects were asked to follow the training program previously designed by coach. They were took 3(g) HMB daily, and fasting blood sample was taken once a week. Bone cytokine OPG and RANKL, and bone specific biochemical markers including osteocalcin, beta-corsslaps, , bone-specific alkaline phosphatase (B-ALP), and hormones parathyroid hormone (PTH) and cortisol, and the expression of the osteoclastogenesis-related protein RANK and IκB-α levels were analyzed to evaluate the bone metabolic status. The results show that bone formation markers osteocalcin continuously increased, accompanied with increased bone resorption marker beta-corsslaps and reached a significant level in the last two weeks, and PTH had the similar tendency. In addition, IκB-α decreased siginificantly in the first week and maintained its level until the end of the training. However in group HMB, B-ALP was significantly higher in the third week and IκB-α significantly lower in the fourth week. Besides, sRANKL and beta-crosslaps appeared have a different tendency in the training session. This research found out that those weightlifters who took 3g HMB daily during the four-week training period could additionally increase the bone formation rate. In addition, it could effectively inhibit the bone resorption rate caused by training.