Discussion
With age comes reduction in the skeletal muscle mass together with reduction in its contraction force. There is also a decline in elasticity and hydration, and loss of innervation; also, there are changes in the contractility of muscle fibers. A reduction in muscle mass and strength, called sarcopenia, usually manifests itself after the age of 60. Researchers search for the cause of the degeneration of the peripheral nervous system that progresses with age, resulting in the loss of motor units. Above the age of 60–70 years, the strength of limb muscles decreases by 20–40%; there is also a reduction in muscular endurance. Chronic diseases can also intensify these processes