Mechanical Properties of Aging Skeletal Muscle

Abstract

Aging skeletal muscle exhibits changes in the tissue architecture, muscle fiber type, and other molecular substructures. These changes often result in sarcopenia, characterized by losses in muscle mass, force generation, contractile velocity, and power. Total force generation is the primary indicator of skeletal muscle strength, and is the summation of the active force produced by muscle fibers and a passive force from the tissue stretching. The elastic and viscoelastic mechanical properties of skeletal muscle can be measured experimentally in vitro, in situ, as well as in vivo for both active and passive muscle. These properties can provide insight into the causes of decreased force generation, but few studies have explored how they change with age. Although some aging-induced increases in passive elastic stiffnessTendonStiffnesshave been documented, their effects on overall muscle function are still unknown. A more complete description of aging effects requires further research into changes in the viscoelastic propertiesLigamentViscoelastic propertiesIntervertebral Disk TissuesViscoelastic propertiesof skeletal muscle and their underlying structural mechanisms.