MUSCLE PLASTICITY WITH RESISTANCE TRAINING AND DETRAINING IN OLDER ADULTS

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。本研究的总体目标是研究年龄对进行性阻力训练、维持性阻力训练和去训练后骨骼肌可塑性的影响。该提案的最初目的是验证以下假设：随着进行性阻力训练，肌肉胰岛素样生长因子- i （IGF-I）的表达/可用性以及配体受体结合下游的肌源性/有丝分裂作用将在年轻（20-30岁）和老年（60-75岁）成年人中增加，并将与肌肉蛋白合成净率的相对增加相关。到第16周，肌纤维大小、大腿瘦质量和力量表现也有类似的相对增加。该提案的第二个目的是验证这样一个假设，即在去训练过程中，阻力训练适应的可逆性在老年男性和女性中比在年轻受试者中发生得更快。该提案的第三个目的是验证这样一个假设，即老年人维持训练适应性所需的最小每周阻力运动量大于年轻人。住院患者肌肉蛋白周转研究（稳定同位素输注）和门诊抽血、激素/底物测定、人体测量、饮食摄入分析、肌肉活检和运动困难都需要GCRC。

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. The overall goal of this proposal is to investigate the impact of age on skeletal muscle plasticity in response to progressive resistance training, maintenance resistance training, and detraining. The initial aim of this proposal is to test the hypothesis that, consequent to progressive resistance training, expression/ availability of muscle insulin-like growth factor-I (IGF-I) and the myogenic/ mitogenic actions downstream from ligand-receptor binding will increase in both younger (20-30 years of age) and older (60-75 years of age) adults and will be associated with similar relative increases in the net rate of muscle protein synthesis by week 8, and similar relative increases in myofiber size, thigh lean mass, and strength performance by week 16. The second aim of this proposal is to test the hypothesis that reversibility of resistance training adaptations during detraining occurs more rapidly in older men and women than in young subjects. The third aim of this proposal is to test the hypothesis that the minimum weekly volume of resistance exercise required to maintain training adaptions is greater in older adults than in younger adults. The GCRC is needed for inpatient muscle protein turnover studies (stable isotope infusions) and outpatient blood draws, hormone/substrate assays, anthropometrics, dietary intake anlysis, muscle biopsies, and exercise difficulty.