Assessing 3D Trunk Strength as a Function of Position and Velocity

描述（由申请人提供）：此申请将允许申请人攻读研究生研究学位，并通过调查运动（机械负荷）在生长过程中对终身骨骼健康的作用，为国家健康科学研究议程做出贡献。运动是骨质疏松症的一种普遍提倡的干预措施，因为骨骼是机械敏感的，可以适应负荷。然而，骨骼对运动有反应的时间（青春期前）和容易发生骨质疏松性骨折的时间（成年期）之间存在差异。这就提出了一个问题，即在生长过程中运动引起的骨骼变化是否会持续到成年，而成年后运动引起的骨骼变化对降低骨折风险最有利。发起人的初步数据表明，负荷引起的皮质骨结构变化是长期维持的，并有助于终身增强骨强度。目前的应用将在三个转化性动物研究中进一步探讨这一点，通过调查：(1)在皮质和小梁部位短期和长期保存负载益处；(2)人工绝经（通过卵巢切除术诱导）对负荷效应保存的影响；(3)负荷引起的变化维持或丧失的潜在机制。在每项研究中，分别采用尺骨或胫骨轴向载荷模型在幼龄大鼠右前肢或后肢诱导骨适应。左四肢将作为无负载的内部控制装置。随后，将对动物进行12,18或92周的训练（限制在笼子里活动），并对一些动物进行卵巢切除术以诱导人工绝经。骨对负荷和去训练的反应将结合体内和体外分析进行评估。为了补充这些动物研究，第四项临床研究将进行，其中将探索投掷运动员作为生长过程中运动对骨骼终身有益的潜在人类模型。这之后

DESCRIPTION (provided by applicant): This application will allow the applicant to pursue a graduate research degree and contribute to the Nation's health sciences research agenda by investigating the role of exercise (mechanical loading) during growth on lifelong skeletal health. Exercise is a commonly advocated intervention for osteoporosis as the skeleton is mechanosensitive and can adapt to loading. However, a disparity exists between when the skeleton is responsive to exercise (pre-puberty) and when it is prone to osteoporotic fracture (adulthood). This has raised the question of whether exercise-induced bone changes during growth persist into adulthood where they would be most advantageous in reducing fracture risk. The sponsors' preliminary data indicate that loading-induced structural changes in cortical bone are maintained long-term and contribute to lifelong enhancement of bone strength. The current application will explore this further in three translational animal studies by investigating: (1) the short- and long-term preservation of loading benefits at both cortical and trabecular sites; (2) the influence of an artificial menopause (induced via ovariectomy) on the preservation of loading effects, and; (3) potential mechanisms for the maintenance or loss of loading-induced changes. In each study, bone adaptation will be induced in the right forelimb or hindlimb of young rats using the ulna or tibial axial loading models, respectively. Left limbs will serve as nonloaded, internal controls. Animals will subsequently be detrained (restricted to cage activities) for 12, 18 or 92 wks, with ovariectomy being performed in some animals to induce an artificial menopause. Bone response to loading and detraining will be assessed using a combination of in vivo and ex vivo analyses. To complement these animal studies, a fourth clinical study will be performed in which throwing athletes will be explored as a potential human model for the lifelong skeletal benefits of exercise during growth. This later study will provide preliminary data for future clinical studies on this topic. PUBLIC HEALTH RELEVANCE: A commonly prescribed treatment for the increased risk for osteoporotic fracture associated with aging is exercise. However, the skeleton is most responsive to exercise around the time of puberty, and not when it is prone to osteoporotic fracture in later adulthood. This has raised the question of whether exercise-induced bone changes during growth persist into adulthood where they would be most advantageous in reducing bone fracture risk. This application will investigate the role of exercise during growth on long-term skeletal health.