MedicalResearch.com Interview with: Brian Clark, Ph.D. Executive Director, Ohio Musculoskeletal and Neurological Institute Osteopathic Heritage Foundation Harold E. Clybourne, D.O. Endowed Research Chair Professor of Physiology OHIO University MedicalResearch.com: What is the background for this study? Response: Muscle weakness strongly contributes to mobility limitations and physical disability. Over 40% of the 46 million older adults in the U.S. have one or more physical limitations when performing daily tasks essential for maintaining independence. Preserving physical function is a major public health priority as it will drastically reduce health care costs and improve quality of life. Over the past several decades, the scientific and medical communities have recognized that muscle weakness is a major factor in determining the incidence of physical limitations and general poor health in older adults. It has long been presumed by many that age-related weakness is principally caused by loss of muscle mass (i.e., sarcopenia). However, over the past 10-20 years the presumption has been questioned. For instance, a 2009 study reported that the decline in leg extensor muscle strength in older adults —observed longitudinally over 5 years—occurs more rapidly than the concomitant loss of quadriceps mass, and that in a subset of older adults that actually gained muscle mass there was still a substantial loss of strength. Findings of this nature clearly illustrate that that the loss of strength is only modestly associated with loss of mass in older adults. The mechanisms of muscle strength, however, are multifactorial and determined by a combination of both neurological and muscular factors (of which muscle mass is one of the factors). (more…)