JUMPING EFFECTS ON GROWING BONES

骨质疏松性骨折正在以惊人的速度增加 并导致每年超过130亿美元的医疗费用。 峰值骨量，即个体S最大骨量出现在 骨骼获取的完成是一个重要的决定因素 骨折风险。成人时期的骨量反映了后天获得的骨量 在增长过程中减去随后损失的部分。因此，最大化 峰值骨量可能提供一种有效的预防策略 骨量减少和骨质疏松症。据推测，增加骨量 降低3%-5%将降低20%-30%的骨折风险。我们的数据 在大学里，女体操运动员展示了臀部和脊椎的骨矿物质 密度值高达40%，高于正常年龄匹配的对照组和 高于精英跑步者，尽管有月经不规律。此外，我们还拥有 体操运动员骨骼对高冲击力的动态响应观察 在训练赛季中，随着骨骼的增加，增加了2-5%。我们计划 随机对照运动干预的效果评价 高冲击负荷作为发育期间增加骨量的一种手段 并将确定腰椎的骨量累积量和骨几何形状 青春期前女孩和男孩的脊柱和股骨近端。此外，我们 建议评估撤除刺激后的骨骼反应 超过6个月。将招募200名青春期前儿童 在两个不同的年份，并随机分配到跳跃或 伸展组。跳跃组将表演双腿跳跃和 伸展组作为对照组。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。我们的提案专门针对相关目标 到RFA中概述的体力活动和锻炼。 在儿童时期实施特定的骨骼加载计划将 潜在地允许骨骼增加其质量和矿化 在较早的年龄，因此提供了更大的基础 从青春期到骨骼的进一步生长的矿化 到了成熟期。我们的发现有望为以下方面提供依据 在生长过程中形成骨骼从而减少体重的策略设计 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.