Muscle is a highly plastic tissue that shows tremendous adaptive potential in response to changes in its pattern of use. This often occurs in the setting of aging and chronic disease, where muscle use decreases. The reduction in muscle use is accompanied by muscle atrophy, weakness and increased fatiguability. Elderly individuals are particularly susceptible to the disabling effects of muscle disuse because of their limited functional reserve. The adaptations in skeletal muscle to disuse in the elderly, however, are largely unknown because of the practical difficulty in performing classical muscle disuse studies (eg, bedrest, casting, etc) in aged humans. The one study that has attempted to address this question has shown that disuse downregulates contractile function and this may be partially explained by a reduction in myosin protein content (D'Antona et al. 2003). Building on this information, and in collaboration with our colleagues in the Department of Orthopedics and Rehabilitation, we recently received funding to conduct a series of studies in elderly individuals with end-stage knee osteoarthritis, a clinical model of chronic muscle disuse. These studies will focus on characterizing adaptations in skeletal muscle size, structure, function and metabolism to chronic disuse at the whole muscle, single fiber and molecular levels. In addition, we will seek to determine the effect of resistance exercise training to modify these various parameters and improve muscle function. These studies will start actively enrolling volunteers in fall '10.
Last modified November 25 2013 09:14 AM