Exercise Maintains Bone Mass, but Do People Maintain Exercise?
Exercise Maintains Bone Mass, but Do People Maintain Exercise?
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运动可以维持骨量，但人们会坚持运动吗？
DOI：
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发表时间：
2001
影响因子：
6.2
通讯作者：
M. Bouxsein
中科院分区：
文献类型：
--
作者：
D. Nelson;M. Bouxsein
人们早就认识到，增加骨骼的机械负荷会导致骨质增加，而减轻骨骼的负荷会导致骨质流失。朱利叶斯·沃尔夫 (Julius Wolff) 的著作中隐含了载荷与骨骼之间的这种关系，他提出骨骼结构（包括矿物质的分布和数量）反映了骨骼所承受的惯常载荷模式。由此可见，增加负重体力活动会增加骨量，并为预防和治疗骨质疏松症提供了一种看似简单的预防策略。这种看似简单的策略在实践中被证明很难实现，因为大多数成人运动干预导致的骨量增加相对较小。然而，即使已知理想的促进骨骼的锻炼方案，人们仍然面临着激励个人为了健康（无论是骨骼健康还是其他健康）进行锻炼的巨大挑战。在本期杂志中，Kontulainen 等人的文章。为维持通过强化运动训练获得的骨骼提供了一些希望，即使随后训练水平降低。这项观察性研究中的受试者最初自行选择参加严格的球拍运动（网球或壁球），平均每周参加四到五次。作者之前报道称，那些在月经初潮前开始训练的女性比在月经初潮后开始训练的女性有更大的骨骼益处（根据玩耍手臂和非玩耍手臂之间骨矿物质含量 (BMC) 的差异进行评估）。 (7)在5年的随访期间，受试者自愿将游戏时间减少到每周一到两次。目前的研究结果表明，尽管训练计划减少了，“年轻的初学者”和“年长的初学者”仍然保持了这种骨骼益处。训练量减少后，年轻先发者的非优势肱骨与优势肱骨的 BMC 差异为 22%，老年先发者为 10%，对照组为 3.5%。尽管这对于我们社会中热爱运动的成员来说是个好消息，但关键问题是受控干预是否会带来类似的好处，并最终降低骨质疏松症和相关骨折的风险。为了更彻底地了解机械负荷、生长和骨骼之间的关系，有必要区分对骨大小和骨密度的影响。 Kontulainen 及其同事用肱骨 BMC 的左右差异来表示骨骼益处。这限制了对其研究结果的可能解释，因为 BMC 测量既反映了骨大小，也反映了骨密度。在骨骼成熟之前，运动对骨骼的影响可能主要通过骨骼大小和形状的改变来调节。 (8) 与仅仅因为骨密度增加而带来的骨骼益处相比，骨骼几何形状的改变所带来的明显的骨骼益处可能更能抵抗随后机械负荷的减少。运动形式的骨骼负荷与骨骼状态之间的精确关系尚未确定。体力活动对骨骼影响的研究因所使用的运动方案、评估的骨骼部位、招募的研究人群和所使用的骨密度测量技术而异。因此，尽管人们普遍认为负重运动对骨骼有积极影响，但很难概括运动干预措施对预防骨质疏松症的公共健康益处。越来越多的证据表明，冲击载荷可能为骨骼提供最大的成骨刺激。 (9-11) 然而，尽管冲击载荷对骨量和密度具有潜在的积极影响，但一些
IT HAS long been recognized that increased mechanical loading of the skeleton results in bone gain, whereas unloading the skeleton leads to bone loss. This relationship between loading and bone is implicit in the writings of Julius Wolff, who proposed that bone structure, including the distribution and amount of mineral, reflect the customary loading patterns that the bone is subjected to. It follows that an increase in weight-bearing physical activity would increase bone mass and present a seemingly simple preventative strategy for prevention and treatment of osteoporosis. This seemingly simple strategy has proven difficult to achieve in practice, because most exercise interventions in adults have led to increases in bone mass that are relatively small. However, even if the ideal bone-promoting ex ercise regimen was known, one would still be faced with the tremendous challenge of motivating individuals to exercise for their health, whether skeletal or otherwise. In this issue of the Journal, the article by Kontulainen et al. offers some hope for the maintenance of bone gained through intensive exercise training, even when the level of training is subsequently reduced. The subjects in this observational study initially self-selected to participate in rigorous racquet sports (tennis or squash) for an average of four to five times per week. The authors previously reported that those women who started training before menarche had a greater skeletal benefit, assessed as the difference in bone mineral content (BMC) between the playing and nonplaying arm, than those who started after menarche. (7) During the 5-year follow-up period, the subjects voluntarily reduced their playing time to just once or twice each week. Results from the current study suggest that both “young starters” and “old starters” maintained this skeletal benefit despite a reduced training schedule. After the reduction in training, the difference in BMC of the nondominant versus dominant humeral shaft was 22% in the young starters, 10% in the old starters, and 3.5% in control subjects. Although this is good news for the athletically inclined members of our society, the critical issue is whether controlled interventions will result in similar benefits and, ultimately, translate to a reduction in the risk of osteoporosis and related fractures. To understand the relationships more thoroughly among mechanical loading, growth, and bone it is essential to distinguish between effects on bone size and bone density. Kontulainen and colleagues represent skeletal benefit in terms of side-to-side differences in humeral BMC. This limits the possible interpretations of their findings, because BMC measurements reflect both bone size as well as bone density. Before skeletal maturity, the effects of exercise on the skeleton may be mediated primarily by alterations in bone size and shape. (8) Apparent skeletal benefits resulting from alterations in skeletal geometry may be more resistant to subsequent reductions in mechanical loading than skeletal benefits solely because of increased bone density. The precise relationships between skeletal loading, in the form of exercise and skeletal status have yet to be defined. Studies of the effects of physical activity on bone vary with respect to the exercise regimen used, skeletal site assessed, study population enrolled, and bone densitometry technique used. As such, it is difficult to generalize about the public health benefits of exercise interventions for the prevention of osteoporosis, although there is general agreement that weight-bearing exercise confers a positive effect on the skeleton. Growing evidence indicates that impact loading may provide the greatest osteogenic stimulus for the keleton. (9–11) However, despite the potentially positive ef fects of impact loading on bone mass and density, some
影响因子：
158.5
作者：
CUMMINGS, SR;NEVITT, MC;VOGT, TM
通讯作者：
VOGT, TM
影响因子：
39.2
作者：
DALSKY, GP;STOCKE, KS;BIRGE, SJ
通讯作者：
BIRGE, SJ
影响因子：
4.1
作者：
Hamrick, MW;McPherron, AC;Hudson, J
通讯作者：
Hudson, J