JUMPING EFFECTS ON GROWING BONES

骨质疏松性骨折正在以惊人的速度增加， 每年造成超过130亿美元的医疗费用。 峰值骨量，即个体在 骨骼获得的完成，是一个重要的决定因素， 骨折风险。 成年期的骨量反映了 减去随后损失的部分。 因此，最大化 峰值骨量可以提供一种有效的策略， 骨质减少和骨质疏松症。 据推测，增加骨量 将骨折风险降低20- 30%。 我们的数据 在大学女子体操运动员展示臀部和脊柱骨矿物质中 密度值比正常年龄匹配的对照高出40%， 尽管月经不规律，但仍高于精英跑步者。 您因前述 观察了体操运动员骨骼对高冲击力的动态反应 在训练季节，骨骼增加了2- 5%。 我们计划 随机对照运动干预，以评估 高冲击负荷作为在发育期间增加骨量的手段 并将确定腰椎的骨量增加和骨几何形状 脊柱和股骨近端的损伤。 我们还 建议评估刺激撤销后的骨反应 超过6个月。 200名青春期前的儿童将被招募 在两个不同的年份，并随机分配到一个跳跃或 拉伸组。 跳跃组将进行双腿跳跃， 拉伸组将作为对照。 结果变量包括 脊柱和髋部的骨密度（BMD），估计的骨体积 脊柱的密度和股骨颈的横截面几何形状 和骨干。 我们的建议具体涉及以下目标： RFA中概述的身体活动和锻炼。 在儿童时期实施特定的骨负荷计划将 潜在地允许骨增加其质量和矿化 在更早的年龄，因此提供了一个更大的基础， 在整个青春期内矿化， 成熟已经达到。 我们的研究结果有望为 在生长过程中构建骨骼的策略的设计， 骨质疏松性骨折

Osteoporotic fractures are increasing at an alarming rate in this country and result in over 13 billion dollars in health costs annually. Peak bone mass, that is, an individual s maximum bone mass at the completion of skeletal acquisition, is an important determinant Of fracture risk. Bone mass during adult life reflects the amount acquired during growth minus that which is subsequently lost. Thus, maximizing peak bone mass may provide an effective strategy toward preventing osteopenia and osteoporosis. It is postulated that increasing bone mass by 3-5 percent would reduce fracture risk by 20-30 percent. Our data in collegiate female gymnasts demonstrate hip and a spine bone mineral density values of up to 40 percent above normal age-matched controls and above elite runners, despite menstrual irregularities. Further, we have observed the dynamic response of bone to high impact forces in gymnasts over the training season as bone increases 2-5 percent. We plan a randomized, controlled exercise intervention to evaluate the effect of high impact loading as a means to increase bone mass during development and will determine bone mass accrual and bone geometry at the lumbar spine and proximal femur in pre-pubescent girls and boys. Further, we propose to evaluate the bone response from withdrawal of the stimulus over 6 months. Two hundred pre-pubescent children will be recruited during two separate years and randomly assigned to a jumping or a stretching group. The jumping group will perform double leg jumps and th stretching group will act as a control. Outcome variables include bone density (BMD) at the spine and hip, estimated bone volumetric density at the spine, and cross-sectional geometry of the femoral neck and diaphysis. Our proposal specifically addresses objectives related to physical activity and exercise that are outlined in the RFA. Implementing a specific bone loading program during childhood will potentially allow the bone to increase both its mass and mineralization at an earlier age and therefore provide a lager foundation of mineralization for further growth throughout adolescence until skeletal maturity is reached. Our findings are expected to provide a basis for the design of strategies to build bone during growth and thereby reduce osteoporotic fractures.