FACTORS REGULATING HUMAN SKELETAL MUSCLE ATROPHY (FKA A QUANTITATIVE TEST

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。摘要：卧床是研究长时间太空飞行中发生的在轨肌肉骨骼变化的极好模拟。我们的新方法包括量化选择的自由生活志愿者受试者的下肢典型的日常负荷，这些受试者不是习惯性的锻炼者，并根据日常负荷刺激理论规划个人运动处方。然后，受试者将被随机分为对照组或运动组，并在克利夫兰临床基金会（CCF）的普通临床研究中心（GCRC）进行6度俯卧12周。在此期间，锻炼组将在CCF独特的零重力运动模拟器（ZLS）中进行个性化的日常锻炼计划，该模拟器旨在取代他们在自由生活中经历的日常机械负荷刺激。将使用与国际空间站类似的跑步机和阻力运动设备进行锻炼。DXA、MRI和QCT扫描将在卧床开始和结束时进行，以评估骨矿物质密度的变化、肌肉体积的变化和骨的区域变化（皮质与小梁）。DXA扫描也将在卧床第8周进行。将收集卧床前和卧床后的强度测量数据，并评估尿液和血清骨吸收和形成标志物。饮食摄入量要足以维持恒定的体重并均衡摄入宏量营养素和微量营养素，将由注册营养师计划和监督，GCRC医生将每天24小时提供服务，以满足任何医疗需求。在卧床休息后的8周内，受试者将接受康复治疗。该实验将为间歇性负荷替代是否能充分保护肌肉骨骼系统免受低运动性骨质减少和肌肉萎缩的问题提供一个明确的答案，并可能开启个体化运动对策规划的新时代。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. GCRC Resource Utilization: Inpatient Stays Nursing Support Ancillary Support ABSTRACT: Bedrest is an excellent analog for the study of on-orbit musculoskeletal changes that occur during long-duration spaceflight. Our novel approach involves quantifying typical daily loads to the lower extremities in selected free-living volunteer subjects who are not habitual exercisers and planning individual exercise prescriptions based on daily load stimulus theory. Subjects will then be randomized to control or exercise groups and confined to 6-degree head-down bedrest in the General Clinical Research Center (GCRC) at the Cleveland Clinic Foundation (CCF) for 12 weeks. During this time, the exercise group will undergo individualized daily exercise programs in the unique Zero Gravity Locomotion Simulator (ZLS) at CCF designed to replace their daily mechanical load stimulus experienced during free living. A treadmill and a resistance-exercise device similar to those available on the International Space Station will be used for exercise. DXA, MRI, and QCT scans will be conducted at the start and end of bedrest to assess variations in bone mineral density, changes in muscle volume, and regional changes (cortical vs. trabecular) in bone. DXA scans will also be conducted at week 8 of bedrest. Strength measurements will be collected pre- and post-bedrest, and urinary and serum markers of bone resorption and formation will also be assessed. Dietary intake sufficient to maintain constant body weight with a balanced intake of macro- and micronutrients will be planned and supervised by a registered dietician, and a GCRC physician will be available 24 hr/day to attend to any medical needs. A rehabilitation program will be offered to subjects in the 8 weeks following bedrest. The proposed experiment should provide a categorical answer to the question of whether intermittent load replacement can adequately protect the musculoskeletal system against hypokinetic osteopenia and muscle atrophy and may open a new era in individualized exercise countermeasure planning.