Aging of Skeletal Muscle Fibers

Abstract

Aging has become an important topic for scientific research because life expectancy and the number of men and women in older age groups have increased dramatically in the last century. This is true in most countries of the world including the Republic of Korea and the United States. From a rehabilitation perspective, the most important associated issue is a progressive decline in functional capacity and independence. Sarcopenia is partly responsible for this decline. Many changes underlying the loss of muscle mass and force-generating capacity of skeletal muscle can be understood at the cellular and molecular levels. Muscle size and architecture are both altered with advanced adult age. Further, changes in myofibers include impairments in several physiological domains including muscle fiber activation, excitation-contraction coupling, actin-myosin cross-bridge interaction, energy production, and repair and regeneration. A thorough understanding of these alterations can lead to the design of improved preventative and rehabilitative interventions, such as personalized exercise training programs.

Frailty and sarcopenia as the basis for the phenotypic manifestation of chronic diseases in older adults

“…Of importance to point out that no consensus have been reached in literature regarding whether there is a shift toward lower (Frontera et al, 2000), higher (Verdijk et al, 2007) or unaltered (Lexell et al, 1988) percentages of type I versus type II in human aging. Likewise with aging there is a reduction, although to a lesser degree, in fiber size that is type specific, being type II fibers largely affected (Miljkovic et al, 2015).…”

Calf circumference: clinical validation for evaluation of muscle mass in the elderly

“…Human aging is accompanied by changes in body composition that include progressive decrease in muscle mass (1) , termed sarcopenia in 1989 by Rosenberg (2) . Currently, sarcopenia is conceptualized as a syndrome, characterized by the gradual and generalized loss not only of muscle mass, but also of muscle strength and function (3) .…”

The Role Of Community Physical Therapy In The Functional Independence And Quality Of Life Of Elderly Women

“…This condition affects between 4% and 27% of the elderly population, varying according to country and gender [17,18]. Sarcopenia is responsible for the loss of muscular strength and immobility, which may aggravate the health condition of the elderly by affecting their functional independence.…”