The muscle fibers shrink. Muscle tissue is replaced more slowly, and lost muscle tissue may be replaced with a tough fibrous tissue. This is most noticeable in the hands, which may become thin and bony. Muscle tissue changes, combined with normal aging changes in the nervous system , cause muscles to have reduced tone and contractility. Muscles may become rigid with age, or may lose tone even if exercised regularly.
Height decreases, primarily caused by shortening of the trunk.
Inflammation, pain, stiffness, and deformity result from breakdown of the joint structures. Almost all older people are affected by joint changes, ranging from minor stiffness to severe arthritis . The neck becomes tilted, and the shoulders narrow. The pelvis, on the other hand, becomes wider. Movement slows and may become limited.