Skeletal muscle is made up of a thousand of fibers that run the length of the muscles. Muscle fiber is made of many contractile units called myofibrils which run the length of each muscle fiber.
When skeletal muscle bond, the two types of fibers slide past each other to materially shorten the muscle. It allows for both the big movements of the body parts and the tight control of small muscles, such as those around the eyes or in the fingers.
