K. E. Yarasheski

Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, Washington University Medical School, St. Louis, Missouri. Correspondence:Kevin E. Yarasheski, PhD, Washington University Medical School, 660 South Euclid Avenue; BOX 8127, Division of Metabolism, Endocrinology and Diabetes, St. Louis, MO 63110. Ph# 314-362-8173. FAX# 314-362-8188. e-mail: key@imgate.wustl.edu

Advancing age appears to alter the chemical and physical properties of skeletal muscle proteins. Alterations include: reduced contractile, mitochondrial, and enzyme protein synthesis rates, altered expression and post-translational modifications to muscle proteins, reduced maximum voluntary muscle strength, reduced muscle strength per unit muscle mass and muscle power. These age-associated impairments in muscle protein quantity and quality contribute to physical disability and frailty, a loss of independent function, the risk of falling and fractures, and contribute to escalating health care costs. Progressive resistance exercise training is a potent, non-pharmacologic, effective therapy that opposes the impairments in muscle protein quantity and quality in middle age and physically frail adults. In the absence of contraindications to exercise, muscle proteins adapt to an exercise training stimulus despite the depredation of age. The proposed pathogenesis for some of these impairments is briefly reviewed. Evidence that supports the use of progressive resistance exercise training to restore muscle quality and quantity in elderly adults is reviewed.