Final answer:
Exercise helps in maintaining the flexibility and elasticity of connective tissue, contrary to the age-related decline in muscle mass and tissue flexibility due to sarcopenia.
Step-by-step explanation:
Regular exercise does not cause loss of flexibility in connective tissue. While aging can lead to a decrease in muscle mass and flexibility due to the replacement of muscle fibers with connective and adipose tissue - a process known as sarcopenia - regular physical activity can help maintain tissue flexibility. Dense connective tissue, especially dense regular elastic tissue, contains elastin fibers alongside collagen fibers, which provide the ability to stretch and return to their original shape. Exercises can help maintain the elasticity of these tissues and thus, prevent the loss of flexibility that is often associated with age-related changes in the body's connective tissues.