Aging is a multidimensional physiological process that affects all people. Biological systems age at various rates with declines in structure and function of up to 3% per year due to a number of different mechanism (90). Many systems have well defined pathologies related to aging; cardiovascular disease, diabetes, osteoporosis, and dementia. The age-related pathology of skeletal muscle is sarcopenia. Sarcopenia is primarily characterized by muscle atrophy and weakness and is highly associated with functional impairment and immobility of the elderly (45). With age, both absolute force production and that normalized to the size of the muscle, or specific force, have noted decrements compared to younger individuals. It is likely that numerous mechanisms with various contributions of each account for the pathology of sarcopenia; such as physical (in)activity, hormonal changes, nutrition, oxidative stress, inflammation, and mitochondrial dysfunction. The main focus in this dissertation is on hormonal changes in females and secondary changes in physical (in)activity.