muscle stiffness causes
Muscle stiffness is caused when the muscles in a certain area of the body contract and become tense. Stiff muscles can happen from a variety of situations. These situations can range from having periods of inactivity to exercising, physical labor or playing sports.he joints in a person's body may experience stiffness from an injury or a strain. Stiffness in the joints can also begin as a person ages. Tendinitis, muscle spasms and arthritis cause pain and stiffness in the joints as well.