Whittington J, Schoen E, Labounty L L, Hamdy R, Ramsey M W, Stone M E, Sands W A, Haff G G, Stone M H
Sports Performance Enhancement Consortium, East Tennessee State University, Johnson City, TN, USA.
J Sports Med Phys Fitness. 2009 Dec;49(4):464-73.
Bone changes in size and density in response to different levels of stress. Alterations to bone mineral density (BMD) appear to occur in a site specific manner. Even though BMD has been examined in many populations there is a paucity of data looking at strength-power athletes, such as throwers. Therefore, the purpose of this study was to examine the BMD of a group of USA Division I collegiate throwers (e.g. shot put, discus, etc.).
Seven throwers (4 males; 3 females) who were 19.0 + or - 0.9 years had their BMD compared to an age matched control group (n = 14; 8 women and 6 men) and normative data. BMD was measured with dual X-ray absorptometry. Potential right/left side and sex difference in BMD were also examined. Maximal isometric strength was assessed using a mid-thigh pull while standing on a forceplate which generated force-time curves. Peak force (PF) and normalized peak force (PFa) were then correlated with BMDs.
Generally, throwers had denser bones with male throwers tending to have a greater total BMD (P < or = 0.05). The dominant arm BMD was slightly greater when compared to non-dominant arm (P < or = 0.05). Furthermore, total body BMD was related to PF (r = 0.68, r(2) = 0.46) and PFa (r = 0.56, r(2) = 0.31).
Throwers have greater BMDs than non-athletes and most other athletes. However, throwers only showed a small indication of sidedness. It is likely that the BMDs observed in this study stem from the training intervention (e.g. whole body heavy lifting) undertaken by this population.
研究骨骼大小和密度对不同应力水平的反应。骨矿物质密度（BMD）的改变似乎具有部位特异性。尽管已经在许多人群中对BMD进行了检测，但针对力量型运动员（如投掷运动员）的数据却很少。因此，本研究的目的是检测一组美国大学体育协会一级联盟的投掷运动员（如铅球、铁饼等项目）的BMD。
选取7名年龄在19.0±0.9岁的投掷运动员（4名男性，3名女性），将他们的BMD与年龄匹配的对照组（n = 14；8名女性和6名男性）以及标准数据进行比较。采用双能X线吸收法测量BMD。还检测了BMD在左右侧以及性别上的潜在差异。使用站立在测力平台上进行的大腿中部拉伸测试来评估最大等长力量，该测试可生成力-时间曲线。然后将峰值力（PF）和标准化峰值力（PFa）与BMD进行相关性分析。
总体而言，投掷运动员的骨骼密度更高，男性投掷运动员的总BMD往往更大（P≤0.05）。优势手臂的BMD比非优势手臂略大（P≤0.05）。此外，全身BMD与PF（r = 0.68，r² = 0.46）和PFa（r = 0.56，r² = 0.31）相关。
投掷运动员的BMD高于非运动员和大多数其他运动员。然而，投掷运动员仅表现出轻微的左右侧差异迹象。本研究中观察到的BMD很可能源于该人群所进行的训练干预（如全身重物举重）。
