Question

How does the muscular system change with age?

Answer 1

Due to the changes in the muscle tissue and normal ageing changes in the nervous system, muscles are less toned and less able to contract. They become rigid with age and may lose tone, even with regular exercise.

Complete answer:
As we age our muscles undergo progressive changes, primarily involving loss of muscle mass and strength. The condition is known as Sarcopenia which includes loss of muscle strength and power, as well as reduced function. It occurs as age increases and is a major component in the development of frailty. Sarcopenia is not a disease but rather refers to the involuntary decline in lean body mass that occurs with age, primarily due to the loss of skeletal muscle.
With increasing age, people lose muscle mass. Around 50% of the total body weight in young adults contributes to lean muscle mass, but this decreases to 25% by 75 to 80 years.
There is a reduction in the cross-sectional area of the lower limb muscle in early adulthood and accelerates beyond 50 years of age. This reduction in muscle cross-sectional area is associated with decreases in contractile structures accompanied by an increase in fat and connective tissue.
The reduction of the total number of muscle fibres is significant with age. It begins at about 25 years and accelerates thereafter. There is a decrease in type II fast-twitch glycolytic fibres due to the decline in the cross-sectional area of muscles.

Note: Sarcopenia has important consequences:
-The reduction of lean body mass reduces function, and loss of approximately 40% of lean body mass is critical.
-It has led to a reduction of muscle size as well as a reduction in satellite cells, mitochondrial numbers, and elasticity.
-It is mostly seen in increasing numbers with advancing age.
-It varies in degree of physical activity, gender, and race.
-It has a considerable effect on function in all activities of daily living, contributing to reduced gait speed, falls, and fractures.