MUSCLE PLASTICITY WITH RESISTANCE TRAINING AND DETRAINING IN OLDER ADULTS

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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.