With advancing age, muscles weaken and lose mass. This makes it harder for older people to gain the benefits of exercise, and eventually it leads to frailty. This process of degeneration was given the name sarcopenia some twenty years ago, and efforts have been underway for some years to have the FDA recognize it as a disease rather than "a normal part of aging." Until the FDA does so, there is no way to raise significant funds for research and development, or make the results of what research has taken place commercially available. It's a sad and sick society we live in, wherein the people at the cutting edge of research - those who know best what needs to be done - must bow and scrape for years so that unelected, unaccountable, ignorant bureaucrats will deign to permit work to proceed.
In any case, here is an open access review paper that serves as a useful introduction to the present state of research into sarcopenia.
The term sarcopenia first coined by Irwin Rosenberg in 1989 is now widely accepted to describe the steady and involuntary loss of skeletal muscle mass during aging. Although the word sarcopenia is used in the field of gerontology to describe this phenomenon of aging, the complex multifactorial changes in muscle fiber quantity and quality, protein synthesis rates, alpha-motor neurons of spinal cord, anabolic and sex hormone production are poorly understood. These changes combine and result in a smaller, slower contracting muscle with impaired capacity to generate sufficient strength and power for activities of daily living.
In 2004, Janssen et al estimated that the annual healthcare cost attributable to sarcopenia was approximately $18 billion in the United States. In the current environment of global aging, the future health burden of sarcopenia is self-evident, and interventions are needed to slow or reverse the loss of muscle mass and function in our aging populations.
The published data on sarcopenia are vast, and this review is not intended to be exhaustive. The aim of this review is to provide an update on the current knowledge of the definition, etiology, consequences, and current clinical trials that may help address this pressing public health problem for our aging populations.
As a researcher noted a while ago:
[When] I was heading aging at Glaxo Smith Kline, the issues that I faced were that I was very interested in developing medications for frailty and weakness in muscle for when people get old because when people get weak they usually stop eating and then they fall and break a hip and end up in the hospital and die potentially, but the regulatory apparatus isn’t there yet. Sarcopenia isn’t recognized as an official disease by the FDA, so the pathway to get drugs approved for frailty and to get more people mobile and into society is just not there.
There's something very wrong with the picture of medical research in this day and age, and that has everything to do with the unchecked growth of government.